Computerized Financial Mangement System

Chapter I Introduction Nowadays one of the major lending businesses that exist today is money lending. It has entered different institutions like banks, government, lending companies and even cooperatives which they offers the kind of business in order for them to gain more profit in an easy way and also to help client by giving loans for special purposes. As the world moves in a globally competitive electronic place, there’s a lot of competition in a technological way but many infrastructure and establishments were still not upgrading their own computers to the latest modern features.They just assure their clients satisfaction by giving a quality service and a friendly environment to every client which is not good enough. Majority of the lending companies nowadays are still using a manual transaction which were indeed a time consuming problem. More on these facts there is also a hard time in computing monthly dues, and balances that made the data not that accurate. This happe ns because of manual calculations in the computer. The proponent is very much concerned in conducting proper studies and implementation of better processes.The proposed system is for Sifcor Lending incorporation by using an automated transaction solution for lending and financial management to improve the current existing method of manual operations. With the advancement of the technology most of the tasks are done in an instant to be competitive nowadays we must experience what really the technology can do. 1. 2 Background of the Study The Sifcor Lending Inc. is a company who let out money for temporary use on condition of repayment with interest. Like other existing loan transaction process Sifcor is also manually operated.They give loans to those who will comply to their requirements, one of these is that an applicant should have shown monthly pay slip and income for the past months or a proof of managing any business. Due to manual operations of the company they are having a har d time in recording and calculating the loans of their clients in a fastest way, but this can be lessen by the use of computer system which could facilitate any operations at faster and easy way. The company only uses their computers for documentation and client’s record keeping purposes and not for their system.Were in fact they are just using Microsoft Word and Microsoft Excel that are usually used Microsoft Office work today and not merely doing the exact specific task they wanted to happen, in this case using of their computer does not help to make their process faster and accurate. Manual calculations were indeed a burden and consume a lot of time on the part of the employees. By developing a Finance Management system the company will have more time in giving emphasis to their other works and responsibility in the company. 1. 3 RationaleNew technologies have become integral to lives of children and young people in the home, industry, business, leisure and communication w ithin a global society. The internet and other digital and information technologies are powerful tools, which open up new opportunities for everyone. As technology grow, so do the demands for better services. The primary reason why the proponent pursue this study is to provide financial management system that will provide the proponent the best chance to apply the knowledge they learn in their years of studying at AMA Computer College.It also gives them opportunity to enhance and practice their ability and creativity. The proposed system will organize the process in which the school conducts its business. The main reason why the proponent came up to an idea of implementing Finance Management System for Sifcor Lending Inc. The proponent proposed a system which can develop a finance management system that will integrate it with the present technology to make transaction easier, faster and user friendly to the employees that will answer the needs of the locale. 1. 4 Information Technol ogy innovationSystem integration is the process of bringing together the different component subsystem into one system and ensuring that subsystem s function together as a system. In information technology, system integration is the process of linking together different computing systems and software application physically or functionally, to act as a coordinated while. In today’s generation technology plays a vital role in our society. The computer technology changes the way we communicate. SIfcor Lending Inc. adapts a system that helps them in managing its company The proponent will be using different kinds of software to develop the proposed system.The technologies used to develop the system are programming language such as Microsoft Visual Basic 6. 0 and My SQL for the database. The proponent will also use Adobe Photoshop CS5 in creating the graphics for the system. This software’s will help the proponent to easily finish the proposed system with the help of their function. 1. 5 Statement of the Problem This section stated the problem being encountered in the existing system. 1. 5. 1 General Problem The general problem as seen by the proponent is to generate a Financial Management System for Sifcor Lending Inc. that will provide an easier, faster and a useful way of lending. . 5. 2 Specific problem The purpose of the study is to generate a Financial Management System for Sifcor Lending Inc. that will provide an easier, faster and a useful way of lending. Specifically, this should be able to solve the following: 1. 5. 2. 1 How to develop a system that will computerized the payment process of SIFCOR Lending Inc. 1. 5. 2. 2 How to develop a system that will enhance security of client records/information? 1. 5. 2. 3 Computation of loans is time consuming and inaccurate due to the use of manual system in computing the loans of the clients using the calculator, paper, and pen. 1. 5. 2. Hard copies of client information are vulnerable to theft, alte rations and misplace. 1. 6 Objectives of the Study 1. 6. 1 General Objective The general objective of the study is to develop a Financial Management System for SIFCOR Lending Inc. 1. 6. 2 Specific Objectives 1. 6. 2. 1 To develop a system that will computerized the payment process of SIFCOR Lending Inc. 1. 6. 2. 2 To develop a system that will enhance security of client records/information? 1. 6. 2. 3 The system will develop a quick and accurate computation of loans by making a system that will automatically compute the loans of the client. . 6. 2. 4 Securing client loans and information. * To develop a system that is secured and free from unauthorized person. 1. 7 Scope and Delimitation 1. 7. 1 Scope The focus of this study is mainly directed towards the design and development of Finance Management for Sifcor Lending Inc. which includes the following procedures1)automatic data calculations 2) loan management; 3)balance inquiry; 4)monthly dues notices; 5) list of clients with approv ed loans; 6) and a loan ledger for the customers payments and balances. 1. 7. Delimitation Transaction such as passing of requirements, loan application, signing of contract, issuance and printing of receipts are no longer included in the system. These are done manually and they need physical appearances of the borrowers. 1. 8 Significance of the study The significance of the study is to give the lending company owner and employees a knowledge and awareness about the new and smart way of using computerized system in their financial management which until at present they are still using manual method.This study will simplify the employee’s workload by automatic calculations of their client’s loans and will minimize their time spent. Doing this automation they could able to finish their other important task timely. 1. 8. 1 Educational The proposed study will serve as a basis of learning for all Information Technology students, this will give an understanding to the Finan cial Management for Lending Companies and will inspire students to develop and make research with the same concept. This will also serve as a reference or related study for future researchers. 1. 8. 2 SocialThe proposed system is socially significant in a way that it is user friendly and is convenient to use. The completion of this research gave the proponent the opportunity to develop his own confidence as he was able to express himself and his ability as an Information Technology student with numerous people who submitted themselves for an interview. 1. 8. 3 Economical The use of the proposed system will help Sifcor Lending Inc. to reduce paper based system like using many ledger cards and to lessen administrative works because the system will automatically compute the clients loan and balances on the expected date of payment. . 8. 4 Technological The proposed system is technologically significant to the proponent and also to the user it’s because with the use of new improv ised system in the computer. The proposed system will help the user to update their knowledge about computer and system use for the benefit of their financial management in Lending to be fast and easy. 1. 9 Definition of terms These terms are defined and included in this chapter for the readers to understand the whole documentation easily. Lending. Disposing of money or property with the expectation that the same thing (or an equivalent) will be returned. Financial.A branch of economics concerned with resource location as well as resource management, acquisition and investment. Simply, finance deals with matters related to money and the markets. To raise money through the issuance and sale of debt and/or equity. Client. Customer  of a  professional  service provider, or the  principal  of an  agent  or  contractor. Chapter II REVIEW OF RELATED LITERATURES AND STUDIES This section contains materials, summary and excerpts of researches and related literatures about the proof of the current study about the proposed solution the proponent deems relevant to the conceptualization of the whole researches. . 1. 1 Foreign Literature According to the thesis of Kristine Mae Mallari, Carissa Garcia the development of development of technology through the years has enabled us to do more with less effort. (Ralph M. Stair; 1999) As the technology continues to advance, computer is becoming more part of our lives. Computers are everywhere at work, at school, and at home. Many daily activities now may involve the use of computer maybe because computers are used in almost every field and profession like education and office works to perform large number of computer application.According to the thesis of Kristine Mae Mallari, Carissa Garcia the database system makes faster for every institution. For the mere fact that instead of doing things manually, with the use of computer technology everything is done faster (Dan Gurewich; 1999) Database management system (DBM S) consist of a collection of interrelated and set of function to access data. DBMS provides an environment that is both convenient and efficient to use in retrieving and storing information. It is also consist of programs for storing, retrieving and manipulating large amount of data.With this article the proponent decided to use a database in storing thee large amount of information taken from the clients profile. It can also enhance manual way of record keeping by having a database. An article found to be linked at http://www. nos. org/htm/sad1. htm, stated that System is created to solves problems. One can think of the systems approach as an organized way of dealing with a problem. In this dynamic world, the subject system analysis and design mainly deals with the software development activities. System life cycle is an organizational process of developing and maintaining systems.It helps in establishing a system project plan, because it gives overall list of processes and sub-pr ocesses required developing a system. 2. 1. 2 Local Literature With the development of the computers, almost half of the business establishments, commercial companies, schools and computer center in the Philippines are completely automated – airlines, hotels, supermarkets and department stores are computers to provide instantaneous and accurate data. And it seems that companies are now taking notice of society’s changing lifestyle. Computers are being compared with the human brains.Like the Brain the advised if, the computer can take data and process it, it can store the data either in raw form or in processing result and can deliver the raw processed data to the outside world demand. Computer works in a very fast way that you can ever imagine. It involves almost everything especially in work like business or school or we can just say a very large population of people. Our country here in the Philippines we can say that we can compete because new technology from other countries has flowed to us. Imagine running a school with large population of students and how will you handle it.Also it affects the kind of environment we have. Here in our country not all business people can provide the needs of their companies. But still with the help of other technology we create a strategy on how will we go on with this kind of problem. People create a system that supports either big or small company. It will be reasonable because these systems meets the requirements of the company and best solutions are suited both environment and networked environment. 2. 2 1 Foreign Studies According to the thesis of Gascon,Arcely M. , Pamintuan, Joseph Carlo C. In an Advance Data System Corporation entitled information and Billing System supports medical Billing Systems, 2011 stated that â€Å"Medical Billing System allows the practice to manage all patient billing and accounting seamlessly and efficiently. It is fully integrated with the EMR, appointment system and charg e capture. Taking advantage of the information flow, it allows quick and easy billing while ensuring a high degree of accuracy and traceability. The system interfaces with leading electronic clearinghouses for electronic claim submission and tracking.With a comprehensive set of reports, it presents all practice management information in an effective manner for analysis and tracking. According to the thesis of Franco,George Ferman M. , Mariano Jr, Romeo C. , Yambao,Mary Grace M. , Automation of the system prove that it generates aped and accuracy, lessen the errors done by manual means and eliminate wasted time that will result for a better service that will cater the company and the employee as well. According to the thesis of Grona, Rusell, manlapaz, Joana Marie M. Business use data processing for such tasks as payroll preparation, accounting, record keeping, inventory control sales analysis, and the processing of bank and credit card account statements. Engineers and scientist use data processing for a wide variety of application, including the processing of seismic data for oil and mineral exploration, the of new product designs, the processing of satellite imagery, and the analysis of data from scientific experiments. Data processing is divided into two kinds of processing: database processing and transaction processing.A database is a collection of common records that can be searched, accessed, and modified, such as bank account records, school transcripts, and income tax data. 2. 2. 2 Local Studies According to the thesis of Elsie Punsalan, Criz Angel Garcia, stated that â€Å"to maximize the usefulness of information, business must manage it correctly, just as it managed other resources manages need to understand that costs are associated with the production, distribution security, storage and retrieval of all information. Although information is all amount us; it is not be taken for granted.In the unpublished thesis entitled manila central cooperative accounting System with Decision Support System by Bautista Catherine and Dela Cruz Juliet A. , Septerber 1996 stated that: â€Å"Computerized Accounting System ffor MMC. Intended to replace the existing manual system in order to make a accounting office work more efficient and beneficial to the members of the employees as well as to the cooperative†. In the unpublished thesis entitled Billing System for Castro Maternity and General Hospital by Maglonzo and Cruzon, 2005 stated that: The system is a major leap forward in computing. It makes computation easier and more fun to use with many user interface and performance enhancement. It will get more work in less time. Professional in every field is discovering knowledge to meet thus change†. Chapter3 3. 1 Theoretical Framework of the Study The Theoretical framework of the study is used to show how the existing and proposed system works. It also illustrates how the proposed system evolved from the existing system. 3. 2 Con ceptual Framework of the Study Figure 3. 2 illustrate how the system flows.Conceptual framework is a group of concept that are broadly defined and systematically organized to provide a focus, a rationale, and a tool for the integration and interpretation of information. 3. 3 Research Setting The proponent conduct a research in SIFCOR LENDING INVESTOR INC. who are also the intended beneficiaries of the proposed system. SIFCOR Lending Investor Inc. is located at Sindalan, City of San Fernando. 3. 4 Research Population The Research Population composed of the company’s employee who gives information that helped the proponent in developing their system.Respondents answered question which expressed their perspectives about the current and proposed system that helped the proponent to further analyze the flow of the system. The Research Population of the proponent composed of the employees and as well the consumers, who are the intended beneficiary of the proposed system. 3. 5 Resear ch design the proponent aim is to satisfy the needs of the users of the study by providing the users with the reliable information which could be a great help. It also discusses the methods uses by the proponent to come up with he procedures on how to identify existing problems in the current system and the procedures on how to develop the proposed system. 3. 5. 1 Descriptive Method This method of research is a fact-finding technique with sufficient meaning. It can help the proponent understand how the current system is supposed to work and determine the comparison and analysis of the existing and the proposed system. It is a way of gathering information to complete the study. This shows the activities that will observe for the development of the existing system.Descriptive Research, also known as statistical research, describe data and characteristics about the population or phhenominon being studied. Descriptive research answer the question who, what, where, when, and how. Althoug h the data description is factual, accurate and systematic, the research canno9t describe what caused a situation. Thus, Description research cannot be used to create a casual relationship, where one variable affect another. In other words, descriptive research can be said to have a low requirements for internal validity. The description is used for frequencies, averages and other statistical calculations.Often the best approach, prior to writing descriptive research, is to conduct a survey investigation. Qualitative research often has the aim of description and researchers may follow-up with examinations of why the observations exist and what the implications of the finding are 3. 6 Methods of Research Used This type of research, as the definition implies, will helps the proponent to collect all the necessary information needed for the implementation of the project. To provide an accurate, fast, efficient and a more convenient way for applying loans is the objective of this project . . 6. 1 Creative Method This research method implies the stylistic approach and aesthetic concept of human experiences that the proponent must acquire in order to develop the proposed system. The proponents used this method in such a way that they made sure that the system would look enticing to its users yet serve the same expected funntionality. 3. 6. 2 Library Method 3. 6. 3 Internet Research Method 3. 7 Data Gathering Techniques and Instrument 3. 7. 1 Observation. The observation of current operating procedures is another fact-finding technique.Seeing the system in action gives the proponents an additional perspective and a better understanding of the system procedures. A personal observation also allow them to verify the statements made in the interviews and determine whether procedures really operate as they are describe. Through observation, they discover that neither the system documentation nor the interview statements are accurate. It provide important advantages as the d evelopment process continues. 3. 7. 2 Interview. The proponent personally interviewed some of the respondents.Personal interview is usually the most expensive fact-finding technique because it is a costly time consuming process. An interview is more familiar and personal than a questionnaire. Respondents who are unwilling to put critical or controversial comments in writing might talk more freely in person. 3. 7. 3 Questionnaires. The proponent used this method because it gives the respondents an opportunity to provide inputs and suggestion. This methods helps distinguish the viewpoint of the respondents who are mainly concern in collecting valuable information about the existing system.Questionnaire construction is critical to the success of a survey. 3. 7. 4 Evaluation These are forms with criteria that evaluate the performance of the existing study. These forms are given to the users that will evaluate the existing system with respect to their efficiency, reliability and effectiv eness. With the help of evaluation form, the proponent were able to analyze the feasibility of the proposed system based from the ratings given by respondents. 3. 8 Analytical tools 3. 8. 1 Ishikawa Diagram 3. 8. 2 Data Flow Diagram Is a graphical representation of the â€Å"flow† of data through an information system.DFD’s were introduced and popularized for structured analysis and design. DFD’s show the flow of data from external entities into the system, showed how the data move from one process to another, as well as its logical storage. The proponents considered the following: In creating the DFD, where does the data that passes through the system come from and where does it go, what delays occur between the inputs and outputs. Using DFD, the proponents can easily analyze the flow of the system that will enable to describe what part of the processing needs to be prioritized. 3. 8. 3 Visual Table of ContentIt is a pictorial means of preventing data. It helps the proponents to display the information needed. It illustrates present systems and describes a proposed system to the user, programmer or operations. 3. 8. 4 Input – Process – Output IPO Model  is a  functional model  and  conceptual schema  of a general  system. An IPO chart identifies a program’s inputs, its outputs, and the processing steps required to transform the inputs into the outputs. Along with a definition, many times you will be asked to draw a diagram to show the stages. It is essential that you learn the diagram below, along with the direction of information flows.You need to be able to reproduce it exactly. 3. 8. 5 Flow Chart 3. 8. 5. 1 Program Flow Chart A program flowchart is a diagrammatic representation that will illustrates the sequence of operations to be performed to get the solution of a problem. The flowchart is a means of visually presenting the flow of data through an information processing systems, the operations perform ed within the system and the sequence in which they are performed. In this lesson, we shall concern ourselves with the program flow chart, which describes what operations are required to solve a given problem.The program flow chart can be likened to the blueprint of a building. As we know a designer draws a blueprint before starting construction on a building. Similarly, a programmer prefers to draw a flow chart prior to writing a computer program. 3. 9 Method Used in Developing the System 3. 9. 1 System Planning. To create a project basic thing to do is to create a plan. The system analyst determines and identifies the planning phase. Identify meaning, to identify the project goals and needs of the system. 3. 9. 2 System analysis. This phase refines project goals into defined functions and operation of the intended application.It analyzes end-user information needs. This is used by the proponent in integrating the lending system to understand and document in detail the business nee ds and the processing of requirements of the proposed system. 3. 9. 3 System Design. A sample structure of the entire study is created in the phase and all necessary data are gathered. It describes the describe features and operations in detail, including screen layouts, business rules, process diagrams and other documentation. The output of this stage will describe the new system as a collection of modules or subsystems.This is used by the proponent to design the proposed system based on the requirements defined and decisions made during the analysis. 3. 9. 4 System Implementation. Modular and subsystem programming code will be accomplished in this phase. Unit testing and module testing are done in the phase by the proponent. This phase is intermingled with the next in that individual modules will need testing before integration to the main project. It is used by the proponent to build, test, and install a reliable system with trained ready to benefit as expected from use of the sy stem. 3. 9. 5 System operation and support. . 10 Justification of Method Used. 3. 11 Method for Product Evaluation. 3. 11. 1 Technical Feasibility. Determines the verification and proving of system accessibility and availability in the local market of the system requirement peripherals such as software and hardware. 3. 11. 2 Operational feasibility. This method determines if the proposed system gives the satisfactory result and output for its target users and market, whether there will be problems in applying and implementing the system in its operational environment in determining the operational feasibility. 3. 11. 2. 1 Efficiency.The ability to complete the result without wasted energy and effort. 3. 11. 2. 2 Reliability Refers to the dependability of the system in performing its intended functions and giving satisfactory results. 3. 11. 2. 3 Effectiveness The degree to achieve the usability of the system and its ability to solve problems encountered of the locale’s curren t system. The Likert’s was applied to the qualitative data collected because its appropriate in evaluating the feedback obtained from respondents. A Likert’s scale measures the extent to which a person agrees or disagrees with the question. Scale| Range of Mean| Verbal Interpretation(VI)| 5| 4. 1-5. 00| excellent| 4| 3. 41-4. 20| Very Satisfactory| 3| 2. 61-3. 40| Satisfactory| 2| 1. 81-2. 60| Fair| 1| 1. 00-1. 80| Poor| Table 3. 1 Likert’s Scale 1. Mean. This was used to determine the average rating of each criteria that was set in the proposed system that the respondent evaluated. The formula for getting the mean is as follows: M= f(X1+X2+X3+†¦Xn) N Where: F=refers to the frequency (f) or the number of times that a given number (x) was chosen by the respondents. (X1 + x2 + x3 + †¦Ã¢â‚¬ ¦. Xn) or any of the numerical ratings (5,4,3,2,1) representing the evaluator’s rating n= represents the sample size of the total number of respondents. . Weigh ted Mean. The weighted mean was used to describe the perception of the respondents concerning the proposed software. To determine the weighted mean, the proponent used the following formula: E f (X1+X2+X3+†¦Xn) N Where: Ef(X1+X2+X3+†¦Xn) = summation of means of all criterion. N= Total number of respondents 3. 12 Statistical treatment of Data This study is essential in order to make used of data in right form by computing them mathematically. The proponent used z-test, this is use by the proponent to make comparative studies between two samples. (See to Appendix M) 1. Formula for Frequency Mean (FM): (X1 + X2 +X3 + †¦ Xn)FM = f _________________________________________ n Where: f = product of the frequency and a particular numeric rating for a given criteria. n = sample size represented by the total number of respondents (X1 + X2 +X3 + †¦ Xn) = any numeric rating 1, 2, 3, 4 and 5 representing the evaluators rating option for each given criteria. 2. Formula for Wei ghted Mean (WM): ? f(X1 + X2 +X3 + †¦ Xn) WM = _______________________________________________ N Where: ? f (X1 + X2 +X3 + †¦ Xn) = the summation of all frequency mean N = total number of criteria 3. T-Test Computation __ __ t =X1 – X2 n1-1(S1)2+ (n2-1)(S2)2n1+ n2-2 1n1+1n2 3. 13 System Development Cost The following formulas are used in computing the total cost in developing the proposed system. Salvage value = (Total Hardware Cost/Life Expentancy)*(Development Period) Months per year Annual Depreciation Cost = (Total Hardware Cost-Salvage Value) Life Expentancy Monthly Depreciation Cost = (Annual Depreciation Cost) Months per year Hardware Development Cost = (Monthly Depreciation Cost * Development Period) Software Development Cost = (Monthly Depreciation Cost * Development Period) Labor Cost = (Developer’s Fee per Month * Development Period)KWh used by Computer = (number of watts * number of hours per month) 1000w KWh used by Electric Fan = (number of watt s * number of hours per month) 1000w KWh used by Light = (number of watts * number of hours per month) 1000w Total Monthly Power Consumption = KWh used by Computer + KWh used by Electric Fan + KWh used by Light Total Basic Charge = Generation Change + Transmission Change + System Loss Change + Distribution Change + Supply Change Total Development Cost = Hardware Cost + Software Cost + Labor Cost + Miscellaneous Cost + Total Overhead Cost

Effects of Technology on Social Groups Essay

The emergence of technology has brought about different social effects. Some have lost while others have gained from the technology. A great part of technology involves working with machines and this has resulted into less human labor and most of the people have been rendered jobless by the machines. This is a negative effect on the social group that was working together since some have to be laid off to give way for the machines. Some people have become wealthier while others have become poor and this has created a gap between the two groups. This has changed the expectations of many people in the social environment (Langdon, 1986). For those who have studied how to work with the machines they are enjoying and getting closer to their social groups. People can easy work from home and this has made working easier. Social groups can work together on the internet and they can even share a network. Most of the technology lies in the computer and through the computer; people can easily talk with all their friends in the social websites. People also find spouses and lost friends on the internet and this is a merit of technology since people keep in touch even when they are far from each other (English-Lueck 1998). In social groups like families, technology has led to breakups of close family ties sine the family members can communicate by sending an email and chatting. They feel that they are close to their relatives even when they are in distant places hence they do not bother to travel home. This has made most of the parents to lose control over their children. This is a way in which technology has created freedom for the young generation (Ruth. 1989). References 1. Ruth Schwartz Cohen, (1989), More work for mother; The Ironies of Household Technology from the open hearth to the Microwave, London, Free Association Books 2. Langdon Winner, (1986), The Whale and the Reactor; A Search for Limits in an Age of High Technology, Chicago, University of Chicago press 3. J. A. English-Lueck, (1998), Technology and Social Change; The effects of family and community retrieved October 31, 2008 from website; http://www. sjsu. edu/depts/anthropology/svcp/SVCPcosa. html

Learnings from Goal

SBM, NMIMS, MUMBAI Goal by Eliyahu M. Goldratt: Learnings Assignment Submitted by: Triparna Chakravorty (E013) Shalini Chhabra (E014) Shirshendu Datta (E015) Darshi Dixit (E016) Abhishek Gambhir (E017) Shivam Garg (E018) 2013 Submitted to: Prof. Pradeep Owalekar, NMIMS, Mumbai MANAGING BUSINESS OPERATIONS Goal by Eliyahu M. Goldratt: Learnings Table of Contents â€Å"Bowl and Stick† Game Description †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 3 Analogy with a production set up †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ Defining Dependency and Variability †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚ ¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. 5 Statistical fluctuations †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. 5 Statistical fluctuation in the Bowl & Stick game †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 5 Relation between dependent events and Statistical fluctuations †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. Effect of statistical fluctuations on Inventory levels †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚ ¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 6 Implications of statistical fluctuations for organizations†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 6 Challenges that statistical fluctuations present in front of organizations †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. 6 How to make more reliable predictions about projects? †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. 6 How to improve the development process itself? †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. Perils of high statis tical fluctuations†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 7 Poor Turnover †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. 7 High Costs †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. 7 Carrying Costs†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. Loss or Damage †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. 7 Shifts in Demand †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 8 Strategic Planning Time †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚ ¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. 8 Lost Sales†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ Higher Expenses †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. 8 Obsolete Merchandise†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. 8 Concept of Balanced Plant †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. 9 Impact of Dependency and Variability on Balanced Plants †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. Unbalanced Processes †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. 9 Fastest to slowest †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚ ¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 10 Result: †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. 10 Slowest to fastest †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 0 Result: †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢ € ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. 10 Randomly distributed capacity†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. 10 Result: †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. 10 Developing a balanced and synchronized plant†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. 0 To design a process with the minimum idle time and maximum through put †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. 11 Conclusion†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 11 2|Page Goal by Eliyahu M. Goldratt: Learnings â€Å"Bowl and Stick† Game Description The bowl and stick game highlights the importance of statistical fluctuations in a process with dependent events and its impact on throughput of the process. Mr. Alex Rogo, the protagonist of the book â€Å"Goal† invents a game wherein there are five bowls on a table and some match sticks.Each bowl is given to a kid who has to manage it. Now every child has to move a number of matchsticks through each of the bowls in succession. The number of sticks each child can move will be determined by the number that tu rns up on a dice that the child has to throw before moving the sticks. For example if a child gets a three upon throwing the dice, he can move at most three sticks ahead. Hence each bowl will move sticks which will fluctuate between one and six based on the number that turns up on the die. Depending on the average number of sticks passed through by each bowl, the average output of the entire process varies.During the course of the game, ? Matches represent the inventory or work in process. ? Bowls represent the different workstations ? Dice is used to determine the Statistical fluctuations Alex reserved a standard quota of 3. 5 which he arrived at by calculating the average of those six numbers on the dice. In order to measure statistical fluctuations, Alex recorded the number appearing on the dice each time the boys threw dice and recorded deviation from the 3. 5 quota. Every player of the game started from zero. If the roll of the die is 4, 5 or 6, then respective gains of 0. 5, 1 . 5 or 2. 5 are recorded.If the outcome from the throw of die comes out to be 1, 2, 3 respective gains of -2. 5, -1. 5 or -0. 5 are recorded. The deviations were taken to be cumulative wherein if somebody recorded a gain of say 2. 5, his starting point on the next turn will be 2. 5 and not zero. According to a mathematical principle, the fluctuations of the variable down the line will fluctuate around the maximum deviation established in the preceding operation. Analogy with a production set up The Bowl and stick game models a simple production process where material is processed sequentially through several workstations.In a typical manufacturing setup, several independent production lines with several workstations exist. An operator usually runs one workstation. A similar setup with six workstations is illustrated in the figure below. Except for the first workstation, each workstation maintains work-in-process inventory. The first workstation takes material from raw material store s, processes the material, and passes it to the work-in-process inventory storage area for station two. Workshop station two eventually 3|Page Goal by Eliyahu M. Goldratt: Learnings processes and moves the material to station three, etc.When a unit of material has been processed by the last workstation, it becomes the system output. Raw materials Station 1 Station 2 Station 3 Station 3 Finished Goods In the game, the roll of a dice is used to simulate actual production capacity of each individual workstation. The potential cycle capacity of the process varies from one to six units, with an average of 3. 5 units. Each child is allowed to process (move) the number of match sticks determined by the roll of the dice, subject to the availability of work-in -process inventory at that station at the beginning of the cycle.No child is permitted to use sticks that were not available at the station at the beginning of the day – those units become part of the next cycle? s work queue. T hus, it often happened that an individual workstation (Bowl in this case) was not able to produce to its capability due to a lack of available materials. The bowls here represent work stations of a manufacturing unit or an organisation and the matches represent production output as well as work in process inventory. Rolling of a die helps to simulate the statistical fluctuations (variation) in performance at each work station or operation.The bowls are set up as a production line representing dependent events where each operation has the same capacity, i. e. , six products per day with a range of variation from one to six. Rolling of the die and determining how many matches to move from one bowl to the next represents one cycle of production run. Each operation is dependent on the upstream operation for input. For e. g. if a scout rolls a five, he can only move four from his bowl if there are only four available to him from the previous bowl (upstream operation) in the process.The p revious operation hence becomes the bottleneck operation. If another player downstream rolls less than a four, then he becomes the bottleneck. Rolling the die several times in sequence represents several cycles of production runs and each time the bottleneck nearly always appears at a different operation or scout. Demonstration through „Bowl and Stick? game is to show that where each operation in a sequence of dependent events has the same amount of capacity (a balanced plant), the variation and dependent events will cause the bottleneck to move from operation to operation, i. . , floating bottlenecks occur. Hence it is difficult for Manager to determine where the bottleneck will show up next and manage the system. 4|Page Goal by Eliyahu M. Goldratt: Learnings Defining Dependency and Variability Dependency is said to exist when certain operations or activities cannot begin until certain other operations or activities have been completed, whereas variability is manifested in th e form of random events and statistical fluctuations. Random events are those events that occur at irregular intervals and have a disruptive effect on the process.Statistical fluctuation refers to the idea that all processes are characterized by some degree of inherent variability. Dependency is manifested in the dice game by the requirement that units of sticks cannot be moved by a workstation until first being passed by all previous workstations. Variability is manifested by the different numbers that may occur when the dice are rolled. Statistical fluctuations Statistical fluctuations occur when one is unable to precisely predict events and quantities and which can only be specified within a certain range.The book gives very good illustrations to explain this principle – Alex and Jonah were sitting in a restaurant and Jonah says that they are able to precisely predict the capacity of the restaurant by counting the available seats. While on the other hand, they are unable t o predict how long the waiter will need to fulfil their order. This uncertainty is referred to as statistical fluctuations. Even if one gets fairly accurate estimates for each stage in the development project, it is still possible, and quite probable, that a project will come in later than expected due to the effects of statistical variation.Statistical fluctuation in the Bowl & Stick game In stick and bowl game Every time the dice is rolled, a random number is generated that is predictable only within a certain range, specifically numbers one to six on each die. This is an example of statistical fluctuations. Relation between dependent events and Statistical fluctuations Dependent events are processes that must first take place before other ones can begin, For example a product has to be assembled before it can be transported.The relation between the statistical fluctuations and the dependent events is expressed as â€Å"Maximum deviation of a preceding operation becomes the start ing point of a subsequent operation. † 5|Page Goal by Eliyahu M. Goldratt: Learnings Effect of statistical fluctuations on Inventory levels The Author predicted that on an average in each round the throughput (No. of matches coming out of the final bowl) should be 3. 5, which is the average of all the possibilities that is, 1 to 6. But after he carried out the experiment 10 times he found that the throughput was significantly lower (21) instead of 35 as predicted.As the process goes on it can be seen that the forecasted throughput is never reached. This happened as the six sided die was causing the variance (statistical fluctuations) by changing the production capacity of each of the stages. Thus, due to the relation between dependent events and Statistical fluctuation each time some step in the process was working as a bottleneck for the capacity of the whole process meaning many sticks were stuck in the intermediate bowls. Hence, statistical fluctuations increase the invento ry (stock) of the system. Implications of statistical fluctuations for organizationsThis in organization setup means: ? The system wastes money by stocking excess inventory that is not immediately converted to throughput, yet raises operational expense in the form of carrying cost. ? Some areas have lower capacity than others and in turn work as a bottleneck for the whole system. In General, Running areas of the factory that have higher capacities will not increase the overall throughput of the system. The measure that the increase is inventory, as the factory produces parts that cannot be assembled into finished goods that will ultimately result into sales until the area of lowest capacity produces enough parts.Inventory is an investment of money and thus subtracts from the bottom-line. Keeping large amounts of inventory is not desirable, because warehouse space is costly. Challenges that statistical fluctuations present in front of organizations How to make more reliable predictio ns about projects? This is one of the major challenges an organization faces. Statistical fluctuations hinder the management to accurately predict the output they can produce as they are unable to gauge the maximum potential of each station.Due to the fluctuations they end up getting lower throughput than predicted which ultimately leads in the late delivery of the orders. 6|Page Goal by Eliyahu M. Goldratt: Learnings How to improve the development process itself? Due to statistical fluctuations, an unregulated development process will be slower than the slowest of the process steps. Therefore, it is impossible to accurately estimate the time required by adding together the time estimates for individual process steps and thus it is difficult to improve the development process. Perils of high statistical fluctuationsOne of the outcomes of high statistical fluctuations is excess inventory. The major disadvantages of the same are: Poor Turnover Companies typically want to produce or ma intain only enough inventories to meet immediate demands and to avoid stock outs. When companies have excessive amounts of inventory, they are generally not selling enough to prevent inventory build-up. This is not a good situation as businesses need to turn over inventory efficiently to maintain reasonably high profit margins and to avoid the costs and other disadvantages that come with high levels of inventory. High CostsCarrying excess inventory has significant costs. One of the highest costs for many companies is financing the purchase and holding of inventory. Also, the more inventories you hold, the more you have to spend on labour to manage it, space to hold it, and in some cases, insurance to protect against its loss or damage. Physically counting and monitoring the levels of inventory you hold also takes time and has costs. Carrying Costs Low inventory turnover can result in higher carrying costs. Inventory needs to be stored, handled and insured, all of which represent cos ts to the business.Stored inventory is also susceptible to shrinkage, which is loss due to occurrences like damage and theft. As with obsolete merchandise, carrying a large volume of slow-moving products also results in lost opportunities due to not being having the storage space for more rapidly turning items. Loss or Damage Related to the high costs of high inventory, some inventory can also go bad after a certain amount of time and go to waste. When retailers buy excess inventory of perishable food items, for instance, they may have to throw out inventory that spoils or becomes rotten.When you carry high inventory, you also have greater exposure to lost or damaged product. Thieves have more products to choose from and you have greater potential for product to turn up missing or broken when you count inventory. 7|Page Goal by Eliyahu M. Goldratt: Learnings Shifts in Demand Another disadvantage of keeping a large amount inventory on hand is that certain goods might not sell due to shifts in market demand. For example, a clothing store that stocks too many tank tops during the summer may find tself unable to get rid of the tank tops before fall. During the fall, consumers might demand different types of clothing, like T -shirts or sweatshirts, leaving the company with a large quantity of goods on hand that simply take up space. Strategic Planning Time Company leaders typically have to spend more time in strategic planning meetings when the company has high inventory levels. Management must figure out how to communicate with suppliers, how to improve ordering processes or how to increase market demand to reduce the high levels of inventory.This problem takes away from the ability of these managers to focus on other proactive or more important strategic decisions to move the company forward. Dealing with inventory problems is a more reactive strategy to resolve the issue at hand. On the other end of spectrum is the problem that arises due to inventory levels get ting too low are: Lost Sales If inventory turns over too quickly, it could negatively affect sales. Merchants may elect to limit the variety of products they carry to prevent a backlog of inventory and keep goods moving through the operation.While merchants might quickly sell the stock they have on hand, they may have difficulty keeping shelves full or may not offer a broad enough selection to meet customer needs. Customers who cannot find what they're looking for or are not impressed with the product mix will look elsewhere and may not return to the establishment. Higher Expenses Merchants who purchase in small quantities to keep inventory turnover high typically incur greater costs. They may not be eligible for volume discounts or special deals available to those who buy in bulk.Transportation costs may also be higher, as manufacturers and distributors often charge higher shipping prices for small orders. In some cases, merchants may have to resort to expensive express delivery me thods to prevent out-of-stock situations. Merchants may need to place orders more frequently, resulting in greater processing expenses. Obsolete Merchandise In operations where inventory turnover is low, merchants run the risk of being stuck with merchandise that becomes unsalable due to obsolescence. This can be a major problem in industries where consumer tastes constantly change or technology rapidly evolves.Carrying obsolete merchandise means the merchant may not have adequate storage space to carry items currently in demand, resulting in lost sales. The merchant may have to resort to selling the merchandise at greatly reduced prices, which reduces its profits. 8|Page Goal by Eliyahu M. Goldratt: Learnings When allocating time for each activity project managers and planners often introduce buffer times. These buffer times might be small numbers for each activity that might be added to guard against statistical fluctuations that normally occur in each activity.While these numbers are small they add up over the entire project activities to a significant time frame. When the workers realize that they have the necessary time built in as buffers they are more likely to push out the start of the job and concentrate their efforts on other task at hand. Concept of Balanced Plant One of the learnings from the bowl and stick game is that dependency and variability will combine to degrade overall plant performance. Several balanced plant models has been proposed to test the hypothesis that increasing (decreasing) levels of dependency and variability will increasingly degrade (improve) plant performance.A balanced plant requires that every workstation have identical capacity. In the context of the game every workstation will have an average capacity of 3. 5 units of matchsticks. Impact of Dependency and Variability on Balanced Plants After understanding the basic dice game setup, the key learning is that in the long run the average number of units of output a plant sh ould be able to produce in every cycle is the mean of the range of outputs that each station can produce which is 3. 5 units in the game.But the plant may not actually achieve the theoretically expected results because of the variations that occur in the output of each workstation which may disturb the balance of the plant. Unbalanced Processes In virtually all processes, the capacities of the various workstations are unbalanced. Goldratt initially developed the production dice game to illustrate the combined effects of dependency and variability on flow processes. Moreover, he combines insights derived from the basic production dice game to provide the foundation for understanding the dynamics in unbalanced plants.Statistical fluctuations disturb the balance of plant which in turn leads to increase in work in process inventory. 9|Page Goal by Eliyahu M. Goldratt: Learnings In The Goal, Goldratt describes three general unbalanced models which are described as follows: Fastest to slo west This occurs when the workstations are arranged according to the fastest producing to the slowest producing. In this model, the first worker transfers the highest output, the second worker lesser, and so on.The average cycle capacities for all the workstations are in order. Result: High output and high inventory Slowest to fastest In this model, the workstations are distributed in order of increasing capacity. That is, the first worker receives transfers the smallest output, the second worker transfers a higher output and so on. Result: low inventory Randomly distributed capacity In this model, different workstations producing at different capacities are randomly distributed in the process line. Result: High output and high

The terms 'ethnic minority' hides the diversity between and within Essay

The terms 'ethnic minority' hides the diversity between and within minority ethnic groups. Discuss - Essay Example dress issues of discrimination on racial or ethnic lives have not been able to efficiently iron out details about ethno-religious matters, gender and ethnicity, ethno-politico issues and other such gray areas. Members of these minority groups have had to endure their situation or fight like the black feminists did. This paper aims to discuss an array issues that touch on this issue of differences between and within ethnic minority groups. Looking at self-employement sector in Britain for example the self-employment rate is 14.6 percent for non-whites compared to 12.3 percent for whites. However beneath this statistics are the glaring differences between the groups. The self-employment rate for black Carribeans is 5.8 percent while that for Chinese is 26.6 percent (Kenneth and Drinkwater, 1). Factors that could create these differences would include social support from one’s community to facilitate a self-sustaining economic environment, effects of religion or access to informal sources of capital and manpower from the family ties or members of the ethnic community (Kenneth and Drinkwater, 1). Cultural endowments too determine such kinds of trends since it does determine one’s attitude towards entrepreneurship. It also has a bearing on consumer behaviour and how much of a good is ordered (Rafiq, 46). Some of these consumer behaviours become so pronounced as to qualify some goods being referred to as ethnic goods. When a good number of members of a certain ethnic group live together in one neighbourhood, a protected market scenario arises. The shop owners are able to maintain a monopoly of sorts within the neighbourhood and the members give support by being loyal to these businesses. The shop owners are keener to provide goods and services that meet the memb ers’ preferences. Religious goods are particularly a favourite. So are goods from the ethnic group’s country of origin. Religion is another strong influence. Rafiq, (50-55) argues that in

Social Technology Essay Example | Topics and Well Written Essays - 750 words

Social Technology - Essay Example She later conceives this idea, perhaps that person view himself absent and hence never minding to talk his personal business in public. The attachment human kinds have with their electronic gadgets had â€Å"turned them cyborgs† (35-36), she writes. It has the ability to make us feel alone, secure and reminiscing about happy moments. It gives solace in the kindest ways human beings have never invented. â€Å"With it†, Sherry observes, referring to collections of his connectivity, â€Å"it is not just that I keep remembering people or I have more ideas†, I feel sociable, invisible. It’s like I’m naked without it. (35-36). People would always prefer to be connected to their â€Å"world† as it provides solace. There is no room for feeling unhappy about anything and have nostalgic feeling. We are always called to multitask with the invention of the new technology. Most people hardly get sleep or wake up in their right foot before being engaged with their gadgets. Sherry observes an interesting point, â€Å"I have discovered that informing myself about daily profession demands is not a healthy way to start or end my day, but state has been unhappily continuing† (36- 37). The connected world have provided so much solace to us such we are already entangled to it and despite persistent efforts to sway away from such behaviors, it is evidently hard to stop. It seems we have irreversibly changed to be robots. At adolescent stage, it is all about finding identity. Most of us at that stage hardly know what to settles on and the mind is always in constant struggle deliberating on matters of life. That the past, with the current trends in communication technology, young people find space that they cherish on being â€Å"online†. They find that desirable space that seems to bring one’s identity as Sherry notes, â€Å"connectivity has the potential to offer new dimension on identity, and particularly in adolescence, it brings the sense of free space

Professional Issues Assignment one Case Study Example | Topics and Well Written Essays - 1000 words

Professional Issues Assignment one - Case Study Example There is an ongoing divorce case and the some data is being required by the lawyers and prosecutors. The psychologist should seek the consent of the client as to what and to whom the information will be given and the purpose that these data will serve. Fidelity is a part of the ethical guidelines stated by BACP. Increasingly, attention has focused on providers of psychological services who need to balance the ethical principles of their profession with legal and regulatory mandates, as well as with the institutional policies of the organizations where they work. The General Guidelines for Providers of Psychological Services and the Specialty Guidelines for the Delivery of Services were promulgated to aide those involved in the professional practice of psychology within several contexts. Additional guidance on specific issues is provided in other documents, such as the Guidelines for Child Custody Evaluations in Divorce Proceedings, drafted by the Committee on Professional Practice and Standards and several others mentioned throughout his chapter. The experiment with Little Albert by Watson and Rayner achieved a great deal of information and additional knowledge that are still considered to helpful up these days in the field of psychology. Watson is a strong proponent of the idea that fear among kids is innate and it can be considered a response to an unconditioned event. The principle of info... The principle of informed consent states that children should be made aware of all the conditions and procedures that they will encounter throughout the research. There should be an approval from the child if he/she wants to participate in the research or not. The child should be provided with the freedom to decide if he/she wants to join or not and the researchers should respect the decision of the child. Non-maleficence states that the procedures should not, in any way, place the child in danger or great harm while doing the research. The psychologist should seek other safer means of doing a procedure if it entails evoking stress from the subject. The psychologist may also ask for more knowledge or assistance from other specialists if they believe that there is a potential danger in one of the steps included in the research. Task Sheet 4: Limits of competence and fitness to practice Competence can be measured by evaluation and can be maintained by keeping a sound professional relationship with clients and sustaining an objective mind to keep away from distractions and pressure. Evaluation is not new in human experience. When Adam and Eve were tempted to partake the apple, a choice was made. President of McKinley spent sleepless nights pondering on whether it was a wise move to buy the Philippines from Spain. The decision he made became a history. Trying on a new dress or buying a new pair of shoes, choosing a course, selecting a university or college - all these involve some appraisal, some evaluation. Evaluation is used to mean appraisal or measurement. As applied to education, it is the process by which we find the extent to which the objectives of the school policies and school program are being attained. Good defines evaluation as the process of determining

Business problem analysis Assignment Example | Topics and Well Written Essays - 250 words

Business problem analysis - Assignment Example An effective business plan should take factor in its calculations the costs, revenue, and flow of cash on a regular basis. This is used to calculate the business’s profitability or discover incidents of loss. Such a plan can be used to project future expenditure plans and guide managers’ decisions about such decisions. The task of understanding such accounting techniques should not be left solely to accountants as managers’ knowledge is critical. Information on the business plans can be presented on a number of models in excel such as charts, graphs, tables, and other presentational formatting. These are further divided into sub-models such as frequency distributions, cumulative frequency distributions, scatter grams and time series distributions. Such presentations provide the selling points for one’s ideas, therefore, they have to be accurate and self-explanatory and simple to understand. The mode of presentation depends on the audience and channel of presentation to be used. Business planning is a strategy that all managers need to learn. Basic accounting techniques are a requirement for all managers and they cannot afford to leave all the accounting to the accountants. Business planning is crucial for a business’s survival and sustenance as it elaborates the business’s future, making vivid aspects that have great impact on the business such as unforeseeable

W7A 590 Whole Foods Essay Example | Topics and Well Written Essays - 500 words

W7A 590 Whole Foods - Essay Example The whole foods store employs the demographic approach to store operations and hiring of new associates to ensure the maximum performance of the store. The demographic method involves the selection of new associates that help operate in most of the whole food store markets. Whole foods also hire new associates that are then divided into team members that help ensure the companies ‘effective management system’ (Shriberg, 2005). To encourage these teams to work harder and to reward them in case of good work the company management gives bonuses to the teams (Hinkin, 2010). These unique management systems employed by the company results to a lot of positive impacts the main one being the fact that the systems contribute to the management of human capital. The effect of these systems in relation to managing human capital is seen through the lower voluntary turnover annually. Through its the company is among the best companies to work for in the world, the positive effects resulting from the two systems employed by the company rise from the way the management system relates to the associates and the employees. In this system, the company holds on to the believe that each employee working in the company has a right to feel the stake in the companys success. Through this, the company has the eight values employed by the employees that attract more customers and provide complete satisfaction to the customers. This tactic result to the organizations competitiveness and success The whole food even with the advantageous approaches faces some challenges mainly resulting from the unending competition in the food industry. Many competition companies adapt the techniques used by the whole food markets, which in turn results in more challenges. However even with the challenges the company manages to fight the competition through its practices (practices that enable the company maintains

ACOLYPSE LITERATURE Essay Example | Topics and Well Written Essays - 750 words

ACOLYPSE LITERATURE - Essay Example The Apocalypse of Abraham is one where the author is not known at present. As a result of this, there have also been several problems in ascertaining its history over a period of time. There have been problems and as a result of this, there was considerable interest in retrieving dates at the very start of its history. The problems that were a part of the ascertaining of the history of this book caused the whole study of it to be disposed of after a certain period of time according to theorists like Robert G. Hall who feel that there has been a â€Å"Christian Interpolation† which introduces certain problems in the interpretation of the figure of Christ (1988, 107). Andrei A. Orlov on the other hand, finds certain strands of Merkabah mysticism in the Apocalypse of Abraham and this can be considered to be one of the reasons as to why these works are considered to be a great part of the traditions of Judaism. Merkabah mysticism is â€Å"the Jewish tradition in which the divine form ideology arguably receives its most advanced articulation† (2008, 53). The apocalypse as far as this book is concerned is the destruction of the temple and this is what is narrated in this book. As a result, one may say that the date of the writing of this book is after 70 A.D. After this point, it is considered to have been translated into Slavonic. There are many versions of history as to what language the original version of the Apocalypse of Abraham was written in. There is however, a certain kind of agreement regarding the fact that the original was written in Hebrew. This is another fact that makes commentators place the work in the tradition of Judaic beliefs. There are theories that there was a stage in between where a translation into Greek was carried out. Translation into English happened, however, during the year 1898. The acquaintance that English audiences have with this work is therefore, limited. This might be

Values of Public and Private Universities Essay Example for Free

Values of Public and Private Universities Essay In the economy we live in today education is of most importance because at some point in time when enhancing our education we will have to decide between public and private universities. In some cases, if they do not one may be unable to acquire a job or be promoted based of their lack of schooling. When a student attends a community college, knowing the next step in their educational career is relevant to secure a future position in a higher and more conventional university. I believe some students are unaware of the significant differences that divide public and private universities. However by understanding the variance between both public and private universities, this will help assist students. Making a more accurately stable conclusion as to which higher education will best benefit them in both the long and short term. If our economy is in majority powered by a standing of schooling, it is of great importance that we select the correct form of university to help achieve a more beneficiary education. It is significant to compare private and public university’s based on their tuition cost, areas of study, graduation accuracy, and campus magnitude to better apprehend the value of each. First, to comprehend the financial standings of schooling it is important to compare the tuition cost of both public and private universities. Additional areas to consider are the school’s annual tuition costs, scholarships, as well as room and bored. According to Christopher Cornwell, a former Exploration Manager, at Eaglewood Energy Inc. and David B. Mustard, an Associate Professor of Economics in the Terry College of Business at the University of Georgia, illustrates that at Georgia’s average four year private university there is a total of 136,581 awards by which 101.91 millions of dollars were presented in total the year of 2002. However, Georgia’s private average annual tuition is near 8,606 dollars. Cost plays a large role in deciding which one out of the two, private and public higher level universities to select to attend; affordability is of main concern. Conversely, Cornwell and Mustard also explained that in the same year of  2002, Georgia’s four year public university has a total of 389,452 awards offered, out of 840.09 millions of dollars stand granted. One online cite, The College Board.com, highly recommended to all college applicants, states that Georgia’s public universities annual tuition nears 4,207 dollars. The contrast of cost fluctuates depending on attending ether public or private universities. Next, when debating between public and private universities it is essential to deliberate the schools areas of study. This includes majors offered, programs, and teaching. Under private universities, rendering Ronald G. Ehrenberg, the Irving M. Ives Professor of Industrial and Labor Relations and Economics at Cornell University, exemplifies that Cornell University consists of four out of ten colleges on its Ithaca campus, â€Å"the Collage of Agriculture and Life Science, Human Ecology, Veterinary Medicine, and the School of Industrial and Labor Relations†. The public university of Alabama at Birmingham School of Public Health specializes in public health programs. Attending a university that specializes in a specific area of study will benefit applicants by high appraisal when applying for jobs in the same area of work (The American Journal of Public Health). One needs to consider graduate accuracy between public and private universities in order to better understand the worth of each one. A graduate rate is a universities average percentage of the total number of students that graduate with a degree within the average time ratio. Contributions to the increase and decrease of any public of private university are based on graduate rates, graduate time period, and job placement. Swarthmore, a small private Philadelphia-based school, will graduate 91% of students within four years, conferring to, Jane Bennett Clark. The public University of North Carolina at Chapel Hill has a 31% admission rate. At 77%, Carolinas four-year graduation rate is 45 percentage points higher than the average rate for four-year public schools according to an article by Susannah Snider. Before selecting ether public or private universities it is important to reflect on each ones graduate rate. Lastly, it is significant to reflect on the campus size magnitude of both  public and private universities. This includes the student to teacher ratio, and the campus total population. According to a report by, Enrolments, Funding and Student Staff Ratios, Policy Note, the average private university withholds an estimate of 1,799,000 student’s total. The public University of Northern Carolina’s fall headcount enrollment in the year 2001reached a high of 3,293, though in the year 2004, 3,574 total enrollment It is projected that by the year 2012 the total fall enrollment will reach 3,717 students (Snider). It is important to take into consideration the total population of every college to decide which large or small learning environment will benefit ones learning progression. In conclusion, one will have the advantage when understanding the importance between public and private universities. Deciding between each one is a resolution that the grander majority of the nation will come to terms with. The importance of understanding the differences between public and private universities is a major area to consider when deciding which university ones believes will fit them best. Base the decision making off of each universities tuition cost, areas of study, magnitude, and graduate rates will help one in their own comparison for which they value most. It is vital to compare public and private universities in order to better recognize each ones distinct value to better determine which learning environment will have the greatest positive impact toward ones education. Citation Page Assessing Public Higher Education in Georgia at the Start of the Twenty-first Century. Whats Happening to Public Higher Education? By Ronald G. Ehrenberg. N.p.: Praeger, 2006. N. pag. Print. CLARK, JANE BENNETT. BEST VALUES IN PRIVATE COLLEGES. (Cover Story). Kiplingers Personal Finance 66.12 (2012): 43-46. Business Source Complete. Web. 23 Oct. 2013. Cornwell, Christopher, and David B. Mustard. Assessing Public Higher Education in Georgia at the Start of the Twenty-first Century. Whats Happening to Public Higher Education? By Ronald G. Ehrenberg. N.p.: Praeger, 2006. N. pag. Print Ehrenberg, Ronald G. Whats Happening to Public Higher Education? Ronald G. Ehrenberg ed. N.p.: Praeger, 2006. Print. Higher Education. Enrolments, Funding and Student Staff Ratios by Sector. Policy Note. Number 2 (2011): 2. Northewest Vista College library one search. Web. Dec. 2011. . SNIDER, SUSANNAH. BEST VALUES IN PUBLIC COLLEGES. (Cover Story). Kiplingers Personal Finance 67.2 (2013): 50. MasterFILE Premier. Web. 30 Oct. 2013. Tuition and Fees by Sector and State over Time. Collegebored.com. N.p., n.d. Web. 15 May 2013. . US Schools Of Public Health And Graduate Public Health Programs Accredited By The Council On Education For Public Health. American Journal Of Public Health 87.3 (1997): 492-494. Business Source Complete. Web. 30 Oct. 2013.

High Performance Wireless Telecommunications Modulation

High Performance Wireless Telecommunications Modulation Introduction The primary goal of the project is to analyze of OFDM system and to assess the suitability of OFDM as a modulation technique for wireless communications. In the part of project is covered two leading successfully implementation of OFDM based technologies are Digital Video Broadcasting (DVB-T and DVB-H) and Long Term Evolution (LTE advanced for 4G). Wireless communications is an emerging field, which has seen enormous growth in the last several years. The huge uptake rate of mobile phone technology, Wireless Local Area Networks (WLAN) and the exponential growth of the Internet have resulted in an increased demand for new methods of obtaining high capacity wireless networks. For cellular mobile applications, we will see in the near future a complete convergence of mobile phone technology, computing, Internet access, and potentially many multimedia applications such as video and high quality audio. In fact, some may argue that this convergence has already largely occurred, with the advent of being able to send and receive data using a notebook computer and a mobile phone. The goal of third and fourth generation mobile networks is to provide users with a high data rate, and to provide a wider range of services, such as voice communications, videophones, and high speed Internet access. The higher data rate of future mobile networks will be achieved by increasing the amount of spectrum allocated to the service and by improvements in the spectral efficiency. OFDM is a potential candidate for the physical layer of fourth generation mobile systems. Basic Principles of OFDM OFDM overview The Orthogonal Frequency Division Multiplexing (OFDM) is a modulation technique where multiple low data rate carriers are combined by a transmitter to form a composite high data rate transmission. The first commercial use of OFDM in the communication field was in the 1980s, and it was later widely used in the broadcast audio and video field in the 1990s in such areas as, ADSL, VHDSL, ETSI standard digital audio broadcast (DAB), digital video broadcast (DVB), and high-definition digital TV (HDTV). Digital signal processing makes OFDM possible. To implement the multiple carrier scheme using a bank of parallel modulators would not be very efficient in analog hardware. However, in the digital domain, multi-carrier modulation can be done efficiently with currently available DSP hardware and software. Not only can it be done, but it can also be made very flexible and programmable. This allows OFDM to make maximum use of available bandwidth and to be able to adapt to changing system requirements. Figure 1 is illustrated, Instead of separate modulators; the outgoing waveform is created by executing a high-speed inverse DFT on a set of time-samples of the transmitted data (post modulation). The output of the DFT can be directly modulated onto the outgoing carrier, without requiring any other components. Each carrier in an OFDM system is a sinusoid with a frequency that is an integer multiple of a base or fundamental sinusoid frequency. Therefore, each carrier is like a Fourier series component of the composite signal. In fact, it will be shown later that an OFDM signal is created in the frequency domain, and then transformed into the time domain via the Discrete Fourier Transform (DFT). Two periodic signals are orthogonal when the integral of their product, over one period, is equal to zero. This is true of certain sinusoids as illustrated in Equation 1. Definition of Orthogonal The carriers of an OFDM system are sinusoids that meet this requirement because each one is a multiple of a fundamental frequency. Each one has an integer number of cycles in the fundamental period. [2, 145-153; 6] The importantance of being orthogonal The main concept in OFDM is orthogonality of the sub-carriers.Since the carriers are all sine/cosine wave, we know that area under one period of a sine or a cosine wave is zero. Lets take a sine wave of frequency m and multiply it by a sinusoid (sine or a cosine) of a frequency n, where both m and n are integers. The integral or the area under this product is given by These two components are each a sinusoid, so the integral is equal to zero over one period. When we multiply a sinusoid of frequency n by a sinusoid of frequency m/n the area under the product is zero. In general for all integers n and m , sin(mx), cos(mx), cos(nx) , sin(nx) are all orthogonal to each other. These frequencies are called harmonics. Making the subcarriers mathematically orthogonal was a breakthrough for OFDM because it enables OFDM receivers to separate the subcarriers via an FFT and eliminate the guard bands. As figure 3 shows, OFDM subcarriers can overlap to make full use of the spectrum, but at the peak of each subcarrier spectrum, the power in all the other subcarriers is zero. OFDM therefore offers higher data capacity in a given spectrum while allowing a simpler system design. Creating orthogonal subcarriers in the transmitter is easy using an inverse FFT. To ensure that this orthogonality is maintained at the receiver (so that the subcarriers are not misaligned), the system must keep the transmitter and receiver clocks closely synchronizedwithin 2 parts per million in 802.11a systems. The 802.11a standard therefore dedicates four of its 52 subcarriers as pilots that enable phase-lock loops in the receiver to track the phase and frequency of the incoming signal. The 802.11a standard therefore dedicates four of its 52 subcarriers as pilots that enable phase-lock loops in the receiver to track the phase and frequency of the incoming signal. This method also eliminates low-frequency phase noise.Separating the subcarriers via an FFT require about an order of magnitude fewer multiply-accumulate operations than individually filtering each carrier. In general, an FFT implementation is much simpler than the RAKE receivers used for CDMA and the decision-feedback equalizers for TDMA.This idea are key to understanding OFDM. The orthogonality allows simultaneously transmission on a lot of sub- carriers in a tight frequency space without interference form each other. In essence this is similar to CDMA, where codes are used to make data sequences independent (also orthogonal) which allows many independent users to transmitin same space successfully.[2, 153-154; 6 ; 7] OFDM Operation Preliminary Concepts When the DFT (Discrete Fourier Transform) of a time signal is taken, the frequency domain results are a function of the time sampling period and the number of samples as shown in Figure 4. The fundamental frequency of the DFT is equal to 1/NT (1/total sample time). Each frequency represented in the DFT is an integer multiple of the fundamental frequency. Parameter Mapping from Time to Frequency for the DFT The maximum frequency that can be represented by a time signal sampled at rate 1/T is fmax = 1/2T as given by the Nyquist sampling theorem. This frequency is located in the center of the DFT points. All frequencies beyond that point are images of the representative frequencies. The maximum frequency bin of the DFT is equal to the sampling frequency (1/T) minus one fundamental (1/NT).The IDFT (Inverse Discrete Fourier Transform) performs the opposite operation to the DFT. It takes a signal defined by frequency components and converts them to a time signal. The parameter mapping is the same as for the DFT. The time duration of the IDFT time signal is equal to the number of DFT bins (N) times the sampling period (T).It is perfectly valid to generate a signal in the frequency domain, and convert it to a time domain equivalent for practical use (The frequency domain is a mathematical tool used for analysis. Anything usable by the real world must be converted into a real, time domain signal). This is how modulation is applied in OFDM. In practice the Fast Fourier Transform (FFT) and IFFT are used in place of the DFT and IDFT, so all further references will be to FFT and IFFT.[1 ,118 ; 4] Definition of Carriers The maximum number of carriers used by OFDM is limited by the size of the IFFT. This is determined as follows in Equation 2. OFDM Carrier Count In order to generate a real-valued time signal, OFDM (frequency) carriers must be defined in complex conjugate pairs, which are symmetric about the Nyquist frequency (fmax). This puts the number of potential carriers equal to the IFFT size/2. The Nyquist frequency is the symmetry point, so it cannot be part of a complex conjugate pair. The DC component also has no complex conjugate. These two points cannot be used as carriers so they are subtracted from the total available. If the carriers are not defined in conjugate pairs, then the IFFT will result in a time domain signal that has imaginary components. This must be a viable option as there are OFDM systems defined with carrier counts that exceed the limit for real-valued time signals given in Equation 2.In general, a system with IFFT size 256 and carrier count 216. This design must result in a complex time waveform. Further processing would require some sort of quadrature technique (use of parallel sine and cosine processing paths). In this report, only real-value time signals will be treated, but in order to obtain maximum bandwidth efficiency from OFDM, the complex time signal may be preferred (possibly an analogous situation to QPSK vs. BPSK). Equation 2, for the complex time waveform, has all IFFT bins available as carriers except the DC bin. Both IFFT size and assignment (selection) of carriers can be dynamic. The transmitter and receiver just have to use the same parameters. This is one of the advantages of OFDM. Its bandwidth usage (and bit rate) can be varied according to varying user requirements. A simple control message from a base station can change a mobile units IFFT size and carrier selection.[2,199-206; 4] Modulation Binary data from a memory device or from a digital processing stream is used as the modulating (baseband) signal. The following steps may be carried out in order to apply modulation to the carriers in OFDM: combine the binary data into symbols according to the number of bits/symbol selected convert the serial symbol stream into parallel segments according to the number of carriers, and form carrier symbol sequences apply differential coding to each carrier symbol sequence convert each symbol into a complex phase representation assign each carrier sequence to the appropriate IFFT bin, including the complex conjugates take the IFFT of the result OFDM modulation is applied in the frequency domain. Figure 5 and Figure 6 give an example of modulated OFDM carriers for one symbol period, prior to IFFT. OFDM Carrier Magnitude prior to IFFT For this example, there are 4 carriers, the IFFT bin size is 64, and there is only 1 bit per symbol. The magnitude of each carrier is 1, but it could be scaled to any value. The phase for each carrier is either 0 or 180 degrees, according to the symbol being sent. The phase determines the value of the symbol (binary in this case, either a 1 or a 0). In the example, the first 3 bits (the first 3 carriers) are 0, and the 4th bit (4th carrier) is a 1. OFDM Carrier Phase prior to IFFT Note that the modulated OFDM signal is nothing more than a group of delta (impulse) functions, each with a phase determined by the modulating symbol. In addition, note that the frequency separation between each delta is proportional to 1/N where N is the number of IFFT bins. The frequency domain representation of the OFDM is described in Equation 3. OFDM Frequency Domain Representation (one symbol period) After the modulation is applied, an IFFT is performed to generate one symbol period in the time domain. The IFFT result is shown in 7. It is clear that the OFDM signal has varying amplitude. It is very important that the amplitude variations be kept intact as they define the content of the signal. If the amplitude is clipped or modified, then an FFT of the signal would no longer result in the original frequency characteristics, and the modulation may be lost. This is one of the drawbacks of OFDM, the fact that it requires linear amplification. In addition, very large amplitude peaks may occur depending on how the sinusoids line up, so the peak-to-average power ratio is high. This means that the linear amplifier has to have a large dynamic range to avoid distorting the peaks. The result is a linear amplifier with a constant, high bias current resulting in very poor power efficiency. OFDM Signal, 1 Symbol Period Figure 8 is provided to illustrate the time components of the OFDM signal. The IFFT transforms each complex conjugate pair of delta functions (each carrier) into a real-valued, pure sinusoid. Figure 8 shows the separate sinusoids that make up the composite OFDM waveform given in Figure 7. The one sinusoid with 180 phase shift is clearly visible as is the frequency difference between each of the 4 sinusoids. Transmission The key to the uniqueness and desirability of OFDM is the relationship between the carrier frequencies and the symbol rate. Each carrier frequency is separated by a multiple of 1/NT (Hz). The symbol rate (R) for each carrier is 1/NT (symbols/sec). The effect of the symbol rate on each OFDM carrier is to add a sin(x)/x shape to each carriers spectrum. The nulls of the sin(x)/x (for each carrier) are at integer multiples of 1/NT. The peak (for each carrier) is at the carrier frequency k/NT. Therefore, each carrier frequency is located at the nulls for all the other carriers. This means that none of the carriers will interfere with each other during transmission, although their spectrums overlap. The ability to space carriers so closely together is very bandwidth efficient. OFDM Time Waveform Figure 9 shows the OFDM time waveform for the same signal. There are 100 symbol periods in the signal. Each symbol period is 64 samples long (100 x 64 = 6400 total samples). Each symbol period contains 4 carriers each of which carries 1 symbol. Each symbol carries 1 bit. Note that Figure 9 again illustrates the large dynamic range of the OFDM waveform envelope. OFDM Spectrum Figure 10 shows the spectrum for of an OFDM signal with the following characteristics: 1 bit / symbol 100 symbols / carrier (i.e. a sequence of 100 symbol periods) 4 carriers 64 IFFT bins spectrum averaged for every 20 symbols (100/20 = 5 averages) Red diamonds mark all of the available carrier frequencies. Note that the nulls of the spectrums line up with the unused frequencies. The four active carriers each have peaks at carrier frequencies. It is clear that the active carriers have nulls in their spectrums at each of the unused frequencies (otherwise, the nulls would not exist). Although it cannot be seen in the figure, the active frequencies also have spectral nulls at the adjacent active frequencies. It is not currently practical to generate the OFDM signal directly at RF rates, so it must be up converted for transmission. To remain in the discrete domain, the OFDM could be upsampled and added to a discrete carrier frequency. This carrier could be an intermediate frequency whose sample rate is handled by current technology. It could then be converted to analog and increased to the final transmit frequency using analog frequency conversion methods. Alternatively, the OFDM modulation could be immediately converted to analog and directly increased to the desired RF transmits frequency. Either way, the selected technique would have to involve some form of linear AM (possibly implemented with a mixer). [1, 122-125; 6] Reception and Demodulation The received OFDM signal is down converted (in frequency) and taken from analog to digital. Demodulation is done in the frequency domain (just as modulation was). The following steps may be taken to demodulate the OFDM: partition the input stream into vectors representing each symbol period take the FFT of each symbol period vector extract the carrier FFT bins and calculate the phase of each calculate the phase difference, from one symbol period to the next, for each carrier decode each phase into binary data sort the data into the appropriate order OFDM Carrier Magnitude following FFT Figure 11 and Figure 12 show the magnitude and spectrum of the FFT for one received OFDM symbol period. For this example, there are 4 carriers, the IFFT bin size is 64, there is 1 bit per symbol, and the signal was sent through a channel with AWGN having an SNR of 8 dB. The figures show that, under these conditions, the modulated symbols are very easy to recover. OFDM Carrier Phase following FFT In Figure 12 that the unused frequency bins contain widely varying phase values. These bins are not decoded, so it does not matter, but the result is of interest. Even if the noise is removed from the channel, these phase variations still occur. It must be a result of the IFFT/FFT operations generating very small complex values (very close to 0) for the unused carriers. The phases are a result of these values. [1, 125 -128; 3] OFDM transceiver OFDM signals are typically generated digitally due to the difficulty in creating large banks of phase lock oscillators and receivers in the analog domain. Figure 13 shows the block diagram of a typical OFDM transceiver. The transmitter section converts digital data to be transmitted, into a mapping of subcarrier amplitude and phase. It then transforms this spectral representation of the data into the time domain using an Inverse Discrete Fourier Transform (IDFT). The Inverse Fast Fourier Transform (IFFT) performs the same operations as an IDFT, except that it is much more computationally efficiency, and so is used in all practical systems. In order to transmit the OFDM signal the calculated time domain signal is then mixed up to the required frequency. Block diagram showing a basic OFDM transceiver [3] The receiver performs the reverse operation of the transmitter, mixing the RF signal to base band for processing, then using a Fast Fourier Transform (FFT) to analyze the signal in the frequency domain. The amplitude and phase of the subcarriers is then picked out and converted back to digital data. The IFFT and the FFT are complementary function and the most appropriate term depends on whether the signal is being received or generated. In cases where the Signal is independent of this distinction then the term FFT and IFFT is used interchangeably. [1, 125 -128, 3] Analysis of OFDM characteristics Guard Period OFDM demodulation must be synchronized with the start and end of the transmitted symbol period. If it is not, then ISI will occur (since information will be decoded and combined for 2 adjacent symbol periods). ICI will also occur because orthogonality will be lost (integrals of the carrier products will no longer be zero over the integration period), To help solve this problem, a guard interval is added to each OFDM symbol period. The first thought of how to do this might be to simply make the symbol period longer, so that the demodulator does not have to be so precise in picking the period beginning and end, and decoding is always done inside a single period. This would fix the ISI problem, but not the ICI problem. If a complete period is not integrated (via FFT), orthogonality will be lost. The effect of ISI on an OFDM signal can be further improved by the addition of a guard period to the start of each symbol. This guard period is a cyclic copy that extends the length of the symbol waveform. Each subcarrier, in the data section of the symbol, (i.e. the OFDM symbol with no guard period added, which is equal to the length of the IFFT size used to generate the signal) has an integer number of cycles. Because of this, placing copies of the symbol end-to-end results in a continuous signal, with no discontinuities at the joins. Thus by copying the end of a symbol and appending this to the start results in a longer symbol time. Addition of a guard period to an OFDM signal [3] In Figure 14, The total length of the symbol is Ts=TG + TFFT, where Ts is the total length of the symbol in samples, TG is the length of the guard period in samples, and TFFT is the size of the IFFT used to generate the OFDM signal. In addition to protecting the OFDM from ISI, the guard period also provides protection against time-offset errors in the receiver. For an OFDM system that has the same sample rate for both the transmitter and receiver, it must use the same FFT size at both the receiver and transmitted signal in order to maintain subcarrier orthogonality. Each received symbol has TG + TFFT samples due to the added guard period. The receiver only needs TFFT samples of the received symbol to decode the signal. The remaining TG samples are redundant and are not needed. For an ideal channel with no delay spread the receiver can pick any time offset, up to the length of the guard period, and still get the correct number of samples, without crossing a symbol boundary. Function of the guard period for protecting against ISI [3] Figure 15 shows this effect. Adding a guard period allows time for the transient part of the signal to decay, so that the FFT is taken from a steady state portion of the symbol. This eliminates the effect of ISI provided that the guard period is longer than the delay spread of the radio channel. The remaining effects caused by the multipath, such as amplitude scaling and phase rotation are corrected for by channel equalization. In order to avoid ISI and ICI, the guard period must be formed by a cyclic extension of the symbol period. This is done by taking symbol period samples from the end of the period and appending them to the front of the period. The concept of being able to do this, and what it means, comes from the nature of the IFFT/FFT process. When the IFFT is taken for a symbol period (during OFDM modulation), the resulting time sample sequence is technically periodic. This is because the IFFT/FFT is an extension of the Fourier Transform which is an extension of the Fourier Series for periodic waveforms. All of these transforms operate on signals with either real or manufactured periodicity. For the IFFT/FFT, the period is the number of samples used. Guard Period via Cyclic Extension With the cyclic extension, the symbol period is longer, but it represents the exact same frequency spectrum. As long as the correct number of samples are taken for the decode, they may be taken anywhere within the extended symbol. Since a complete period is integrated, orthogonality is maintained. Therefore, both ISI and ICI are eliminated. Note that some bandwidth efficiency is lost with the addition of the guard period (symbol period is increased and symbol rate is decreased) [2,154-160, 3] Windowing The OFDM signal is made up of a series of IFFTs that are concatenated to each other. At each symbol period boundary, there is a signal discontinuity due to the differences between the end of one period and the start of the next. These discontinuities can cause high frequency spectral noise to be generated (because they look like very fast transitions of the time waveform). To avoid this, a window function (Hamming, Hanning, Blackman, ) may be applied to each symbol period. The window function would attenuate the time waveform at the start and the end of each period, so that the discontinuities are smaller, and the high frequency noise is reduced. However, this attenuation distorts the signal and some of the desired frequency content is lost.[1, 121;2 154] Multipath Characteristics OFDM avoids frequency selective fading and ISI by providing relatively long symbol periods for a given data rate. This is illustrated in Figure 17. For a given transmission channel and a given source data rate, OFDM can provide better multipath characteristics than a single carrier. OFDM vs. Single Carrier, Multipath Characteristic Comparison However, since the OFDM carriers are spread over a frequency range, there still may be some frequency selective attenuation on a time-varying basis. A deep fade on a particular frequency may cause the loss of data on that frequency for a given time, but the use of Forward Error Coding can fix it. If a single carrier experienced a deep fade, too many consecutive symbols may be lost and correction coding may be ineffective. [8] Bandwidth A comparison of RF transmits bandwidth between OFDM and a single carrier is shown in Figure 18 (using the same example parameters as in Figure 17). OFDM Bandwidth Efficiency In Figure 18, the calculations show that OFDM is more bandwidth efficient than a single carrier. Note that another efficient aspect of OFDM is that a single transmitters bandwidth can be increased incrementally by addition of more adjacent carriers. In addition, no bandwidth buffers are needed between transmit bandwidths of separate transmitters as long as orthogonality can be maintained between all the carriers.[2, 161-163; 8; 9] Physical Implementation Since OFDM is carried out in the digital domain, there are many ways it can be implemented. Some options are provided in the following list. Each of these options should be viable given current technology: ASIC (Application Specific Integrated Circuit) ASICs are the fastest, smallest, and lowest power way to implement OFDM Cannot change the ASIC after it is built without designing a new chip General-purpose Microprocessor or MicroController PowerPC 7400 or other processor capable of fast vector operations Highly programmable Needs memory and other peripheral chips Uses the most power and space, and would be the slowest Field-Programmable Gate Array (FPGA) An FPGA combines the speed, power, and density attributes of an ASIC with the programmability of a general purpose processor. An FPGA could be reprogrammed for new functions by a base station to meet future (currently unknown requirements).This should be the best choice.[9] OFDM uses in DVB (Digital Video Broadcasting) DVB (Digital Video Broadcast) is a set of standards for the digital transmission of video and audio streams, and also data transmission. The DVB standards are maintained by the DVB Project, which is an industry-led consortium of over 260 broadcasters, manufacturers, network operators, software developers, regulatory bodies and others in over 35 countries. DVB has been implemented over satellite (DVB-S, DVB-S2), cable (DVB-C), terrestrial broadcasting (DVB-T), and handheld terminals (DVB-H). the DVB standard following the logical progression of signal processing steps, as well as source and channel coding, COFDM modulation, MPEG compression and multiplexing methods, conditional access and set-top box Technology. In this project is presented an investigation of two OFDM based DVB standards, DVB-T and DVB-H. DVB-T (Digital Video Broadcasting Terrestrial) The first Terrestrial Digital Video Broadcasting pilot transmissions were started in the late 90s, and the first commercial system was established in Great Britain. In the next few years the digital broadcasting system has been set up in many countries, and the boom of the digital terrestrial transmission is estimated in the next few years, while the analogue transmission will be cancelled within about 15 years. The greatest advantage of the digital system is the effective use of the frequency spectrum and its lower radiated power in comparison with the analogue transmission, while the covered area remains the same. Another key feature is the possibility of designing a so-called Single Frequency Network (SFN), which means that the neighboring broadcast stations use the same frequency and the adjacent signals dont get interfered. The digital system transmits a data stream, which means that not only television signals but data communication (e.g. Internet service) may be used according to the demands. The data stream consists of an MPEG-2 bit stream, which means a compression is used, enabling the transfer of even 4 or 5 television via the standard 8 MHz wide TV channel. For the viewer, the main advantages are the perfect, noise-free picture, CD quality sound, and easier handling, as well as services like Super Teletext, Electronic Programme Guide, interactivity and mobility.[11, 251-253] Modulation technique in DVB-T The DVB-T Orthogonal Frequency Division Multiplexing (OFDM) modulation system uses multi-carrier transmission. There are 2 modes, the so-called 2k and 8k modes, using 1705 and 6817 carriers respectively, with each carrier modulated separately and transmitted in the 8 MHz TV channel. The common modulation for the carriers is typically QPSK, 16-QAM or 64-QAM. Each signal can be divided into two, so-called „In Phase (I) and „Quadrature Phase components, being a 90Â ° phase shift between them. The constellation diagram and the bit allocation is shown in bellow 16-QAM constellation diagram and bit allocation [6] This modulation can be demonstrated in the constellation diagram, where the 2 axes represent the 2 components (I and Q). In case of using 16-QAM modulation, the number of states is 16, so 1 symbol represents 4 bits. [11, 255; 6; 14] Bir errors If we simulate all the carriers in the constellation diagram we get not just 1 discrete point, but many points, forming a „cloud and representing each state. In case of additive noise the „cloud gets bigger and the receiver may decide incorrectly, resulting in bit errors. Figure 2 shows the measured constellation diagram without and with additive noise. Measured 16-QAM constellation diagram a) without additive noise b) with additive noise [6] To ensure perfect picture quality, the DVB-T system uses a 2 level error correction (Reed-Solomon and Viterbi). This corrects the bad bits at an even 10-4 Bit Error Rate (BER) and enables error-free data transmission. [13, 32-36] The multi-carrier structure The structure of carriers can be illustrated also in the function of time (Figure 20). The horizontal axis is the frequency and the vertical axis is the time. The 8 MHz channel consists of many carriers, placed 4462 Hz or 1116 Hz far from each other according to the modulation mode (2k or 8k). Structure of OFDM carriers [13] There are some reserved, so-called Transmission Parameter Signalling (TPS) carriers that do not transfer payload, just provide transmission mode information for the receiver, so the total number of useful carriers is 1512 and 6048 respectively in the two transmission modes, and the resultant bit rate is between 4,97 and 31,66 Mbit/s, depending on the modulation (QPSK, 16-QAM or 64-QAM), the transmission mode (2k or 8k), the Code Rate (CR) used for error correction and the selected Guard Interval (GI). This guard interval means that there is a small time gap between each symbol, so the transmission is not continuous. This guarding time enables perfect reception by eliminating the errors caused by multipath propagation.[4, 79-90; 13] Frequency spectrum In 2k mode, 1705 carriers are modulated in the 8 MHz TV channel, so each carrier is 4462 Hz far from its neighbor, while in 8k mode this distance is 1116 Hz. In digital broadcasting, there are no vision and sound carriers, so the power for each carrier is the same. This mean High Performance Wireless Telecommunications Modulation High Performance Wireless Telecommunications Modulation Introduction The primary goal of the project is to analyze of OFDM system and to assess the suitability of OFDM as a modulation technique for wireless communications. In the part of project is covered two leading successfully implementation of OFDM based technologies are Digital Video Broadcasting (DVB-T and DVB-H) and Long Term Evolution (LTE advanced for 4G). Wireless communications is an emerging field, which has seen enormous growth in the last several years. The huge uptake rate of mobile phone technology, Wireless Local Area Networks (WLAN) and the exponential growth of the Internet have resulted in an increased demand for new methods of obtaining high capacity wireless networks. For cellular mobile applications, we will see in the near future a complete convergence of mobile phone technology, computing, Internet access, and potentially many multimedia applications such as video and high quality audio. In fact, some may argue that this convergence has already largely occurred, with the advent of being able to send and receive data using a notebook computer and a mobile phone. The goal of third and fourth generation mobile networks is to provide users with a high data rate, and to provide a wider range of services, such as voice communications, videophones, and high speed Internet access. The higher data rate of future mobile networks will be achieved by increasing the amount of spectrum allocated to the service and by improvements in the spectral efficiency. OFDM is a potential candidate for the physical layer of fourth generation mobile systems. Basic Principles of OFDM OFDM overview The Orthogonal Frequency Division Multiplexing (OFDM) is a modulation technique where multiple low data rate carriers are combined by a transmitter to form a composite high data rate transmission. The first commercial use of OFDM in the communication field was in the 1980s, and it was later widely used in the broadcast audio and video field in the 1990s in such areas as, ADSL, VHDSL, ETSI standard digital audio broadcast (DAB), digital video broadcast (DVB), and high-definition digital TV (HDTV). Digital signal processing makes OFDM possible. To implement the multiple carrier scheme using a bank of parallel modulators would not be very efficient in analog hardware. However, in the digital domain, multi-carrier modulation can be done efficiently with currently available DSP hardware and software. Not only can it be done, but it can also be made very flexible and programmable. This allows OFDM to make maximum use of available bandwidth and to be able to adapt to changing system requirements. Figure 1 is illustrated, Instead of separate modulators; the outgoing waveform is created by executing a high-speed inverse DFT on a set of time-samples of the transmitted data (post modulation). The output of the DFT can be directly modulated onto the outgoing carrier, without requiring any other components. Each carrier in an OFDM system is a sinusoid with a frequency that is an integer multiple of a base or fundamental sinusoid frequency. Therefore, each carrier is like a Fourier series component of the composite signal. In fact, it will be shown later that an OFDM signal is created in the frequency domain, and then transformed into the time domain via the Discrete Fourier Transform (DFT). Two periodic signals are orthogonal when the integral of their product, over one period, is equal to zero. This is true of certain sinusoids as illustrated in Equation 1. Definition of Orthogonal The carriers of an OFDM system are sinusoids that meet this requirement because each one is a multiple of a fundamental frequency. Each one has an integer number of cycles in the fundamental period. [2, 145-153; 6] The importantance of being orthogonal The main concept in OFDM is orthogonality of the sub-carriers.Since the carriers are all sine/cosine wave, we know that area under one period of a sine or a cosine wave is zero. Lets take a sine wave of frequency m and multiply it by a sinusoid (sine or a cosine) of a frequency n, where both m and n are integers. The integral or the area under this product is given by These two components are each a sinusoid, so the integral is equal to zero over one period. When we multiply a sinusoid of frequency n by a sinusoid of frequency m/n the area under the product is zero. In general for all integers n and m , sin(mx), cos(mx), cos(nx) , sin(nx) are all orthogonal to each other. These frequencies are called harmonics. Making the subcarriers mathematically orthogonal was a breakthrough for OFDM because it enables OFDM receivers to separate the subcarriers via an FFT and eliminate the guard bands. As figure 3 shows, OFDM subcarriers can overlap to make full use of the spectrum, but at the peak of each subcarrier spectrum, the power in all the other subcarriers is zero. OFDM therefore offers higher data capacity in a given spectrum while allowing a simpler system design. Creating orthogonal subcarriers in the transmitter is easy using an inverse FFT. To ensure that this orthogonality is maintained at the receiver (so that the subcarriers are not misaligned), the system must keep the transmitter and receiver clocks closely synchronizedwithin 2 parts per million in 802.11a systems. The 802.11a standard therefore dedicates four of its 52 subcarriers as pilots that enable phase-lock loops in the receiver to track the phase and frequency of the incoming signal. The 802.11a standard therefore dedicates four of its 52 subcarriers as pilots that enable phase-lock loops in the receiver to track the phase and frequency of the incoming signal. This method also eliminates low-frequency phase noise.Separating the subcarriers via an FFT require about an order of magnitude fewer multiply-accumulate operations than individually filtering each carrier. In general, an FFT implementation is much simpler than the RAKE receivers used for CDMA and the decision-feedback equalizers for TDMA.This idea are key to understanding OFDM. The orthogonality allows simultaneously transmission on a lot of sub- carriers in a tight frequency space without interference form each other. In essence this is similar to CDMA, where codes are used to make data sequences independent (also orthogonal) which allows many independent users to transmitin same space successfully.[2, 153-154; 6 ; 7] OFDM Operation Preliminary Concepts When the DFT (Discrete Fourier Transform) of a time signal is taken, the frequency domain results are a function of the time sampling period and the number of samples as shown in Figure 4. The fundamental frequency of the DFT is equal to 1/NT (1/total sample time). Each frequency represented in the DFT is an integer multiple of the fundamental frequency. Parameter Mapping from Time to Frequency for the DFT The maximum frequency that can be represented by a time signal sampled at rate 1/T is fmax = 1/2T as given by the Nyquist sampling theorem. This frequency is located in the center of the DFT points. All frequencies beyond that point are images of the representative frequencies. The maximum frequency bin of the DFT is equal to the sampling frequency (1/T) minus one fundamental (1/NT).The IDFT (Inverse Discrete Fourier Transform) performs the opposite operation to the DFT. It takes a signal defined by frequency components and converts them to a time signal. The parameter mapping is the same as for the DFT. The time duration of the IDFT time signal is equal to the number of DFT bins (N) times the sampling period (T).It is perfectly valid to generate a signal in the frequency domain, and convert it to a time domain equivalent for practical use (The frequency domain is a mathematical tool used for analysis. Anything usable by the real world must be converted into a real, time domain signal). This is how modulation is applied in OFDM. In practice the Fast Fourier Transform (FFT) and IFFT are used in place of the DFT and IDFT, so all further references will be to FFT and IFFT.[1 ,118 ; 4] Definition of Carriers The maximum number of carriers used by OFDM is limited by the size of the IFFT. This is determined as follows in Equation 2. OFDM Carrier Count In order to generate a real-valued time signal, OFDM (frequency) carriers must be defined in complex conjugate pairs, which are symmetric about the Nyquist frequency (fmax). This puts the number of potential carriers equal to the IFFT size/2. The Nyquist frequency is the symmetry point, so it cannot be part of a complex conjugate pair. The DC component also has no complex conjugate. These two points cannot be used as carriers so they are subtracted from the total available. If the carriers are not defined in conjugate pairs, then the IFFT will result in a time domain signal that has imaginary components. This must be a viable option as there are OFDM systems defined with carrier counts that exceed the limit for real-valued time signals given in Equation 2.In general, a system with IFFT size 256 and carrier count 216. This design must result in a complex time waveform. Further processing would require some sort of quadrature technique (use of parallel sine and cosine processing paths). In this report, only real-value time signals will be treated, but in order to obtain maximum bandwidth efficiency from OFDM, the complex time signal may be preferred (possibly an analogous situation to QPSK vs. BPSK). Equation 2, for the complex time waveform, has all IFFT bins available as carriers except the DC bin. Both IFFT size and assignment (selection) of carriers can be dynamic. The transmitter and receiver just have to use the same parameters. This is one of the advantages of OFDM. Its bandwidth usage (and bit rate) can be varied according to varying user requirements. A simple control message from a base station can change a mobile units IFFT size and carrier selection.[2,199-206; 4] Modulation Binary data from a memory device or from a digital processing stream is used as the modulating (baseband) signal. The following steps may be carried out in order to apply modulation to the carriers in OFDM: combine the binary data into symbols according to the number of bits/symbol selected convert the serial symbol stream into parallel segments according to the number of carriers, and form carrier symbol sequences apply differential coding to each carrier symbol sequence convert each symbol into a complex phase representation assign each carrier sequence to the appropriate IFFT bin, including the complex conjugates take the IFFT of the result OFDM modulation is applied in the frequency domain. Figure 5 and Figure 6 give an example of modulated OFDM carriers for one symbol period, prior to IFFT. OFDM Carrier Magnitude prior to IFFT For this example, there are 4 carriers, the IFFT bin size is 64, and there is only 1 bit per symbol. The magnitude of each carrier is 1, but it could be scaled to any value. The phase for each carrier is either 0 or 180 degrees, according to the symbol being sent. The phase determines the value of the symbol (binary in this case, either a 1 or a 0). In the example, the first 3 bits (the first 3 carriers) are 0, and the 4th bit (4th carrier) is a 1. OFDM Carrier Phase prior to IFFT Note that the modulated OFDM signal is nothing more than a group of delta (impulse) functions, each with a phase determined by the modulating symbol. In addition, note that the frequency separation between each delta is proportional to 1/N where N is the number of IFFT bins. The frequency domain representation of the OFDM is described in Equation 3. OFDM Frequency Domain Representation (one symbol period) After the modulation is applied, an IFFT is performed to generate one symbol period in the time domain. The IFFT result is shown in 7. It is clear that the OFDM signal has varying amplitude. It is very important that the amplitude variations be kept intact as they define the content of the signal. If the amplitude is clipped or modified, then an FFT of the signal would no longer result in the original frequency characteristics, and the modulation may be lost. This is one of the drawbacks of OFDM, the fact that it requires linear amplification. In addition, very large amplitude peaks may occur depending on how the sinusoids line up, so the peak-to-average power ratio is high. This means that the linear amplifier has to have a large dynamic range to avoid distorting the peaks. The result is a linear amplifier with a constant, high bias current resulting in very poor power efficiency. OFDM Signal, 1 Symbol Period Figure 8 is provided to illustrate the time components of the OFDM signal. The IFFT transforms each complex conjugate pair of delta functions (each carrier) into a real-valued, pure sinusoid. Figure 8 shows the separate sinusoids that make up the composite OFDM waveform given in Figure 7. The one sinusoid with 180 phase shift is clearly visible as is the frequency difference between each of the 4 sinusoids. Transmission The key to the uniqueness and desirability of OFDM is the relationship between the carrier frequencies and the symbol rate. Each carrier frequency is separated by a multiple of 1/NT (Hz). The symbol rate (R) for each carrier is 1/NT (symbols/sec). The effect of the symbol rate on each OFDM carrier is to add a sin(x)/x shape to each carriers spectrum. The nulls of the sin(x)/x (for each carrier) are at integer multiples of 1/NT. The peak (for each carrier) is at the carrier frequency k/NT. Therefore, each carrier frequency is located at the nulls for all the other carriers. This means that none of the carriers will interfere with each other during transmission, although their spectrums overlap. The ability to space carriers so closely together is very bandwidth efficient. OFDM Time Waveform Figure 9 shows the OFDM time waveform for the same signal. There are 100 symbol periods in the signal. Each symbol period is 64 samples long (100 x 64 = 6400 total samples). Each symbol period contains 4 carriers each of which carries 1 symbol. Each symbol carries 1 bit. Note that Figure 9 again illustrates the large dynamic range of the OFDM waveform envelope. OFDM Spectrum Figure 10 shows the spectrum for of an OFDM signal with the following characteristics: 1 bit / symbol 100 symbols / carrier (i.e. a sequence of 100 symbol periods) 4 carriers 64 IFFT bins spectrum averaged for every 20 symbols (100/20 = 5 averages) Red diamonds mark all of the available carrier frequencies. Note that the nulls of the spectrums line up with the unused frequencies. The four active carriers each have peaks at carrier frequencies. It is clear that the active carriers have nulls in their spectrums at each of the unused frequencies (otherwise, the nulls would not exist). Although it cannot be seen in the figure, the active frequencies also have spectral nulls at the adjacent active frequencies. It is not currently practical to generate the OFDM signal directly at RF rates, so it must be up converted for transmission. To remain in the discrete domain, the OFDM could be upsampled and added to a discrete carrier frequency. This carrier could be an intermediate frequency whose sample rate is handled by current technology. It could then be converted to analog and increased to the final transmit frequency using analog frequency conversion methods. Alternatively, the OFDM modulation could be immediately converted to analog and directly increased to the desired RF transmits frequency. Either way, the selected technique would have to involve some form of linear AM (possibly implemented with a mixer). [1, 122-125; 6] Reception and Demodulation The received OFDM signal is down converted (in frequency) and taken from analog to digital. Demodulation is done in the frequency domain (just as modulation was). The following steps may be taken to demodulate the OFDM: partition the input stream into vectors representing each symbol period take the FFT of each symbol period vector extract the carrier FFT bins and calculate the phase of each calculate the phase difference, from one symbol period to the next, for each carrier decode each phase into binary data sort the data into the appropriate order OFDM Carrier Magnitude following FFT Figure 11 and Figure 12 show the magnitude and spectrum of the FFT for one received OFDM symbol period. For this example, there are 4 carriers, the IFFT bin size is 64, there is 1 bit per symbol, and the signal was sent through a channel with AWGN having an SNR of 8 dB. The figures show that, under these conditions, the modulated symbols are very easy to recover. OFDM Carrier Phase following FFT In Figure 12 that the unused frequency bins contain widely varying phase values. These bins are not decoded, so it does not matter, but the result is of interest. Even if the noise is removed from the channel, these phase variations still occur. It must be a result of the IFFT/FFT operations generating very small complex values (very close to 0) for the unused carriers. The phases are a result of these values. [1, 125 -128; 3] OFDM transceiver OFDM signals are typically generated digitally due to the difficulty in creating large banks of phase lock oscillators and receivers in the analog domain. Figure 13 shows the block diagram of a typical OFDM transceiver. The transmitter section converts digital data to be transmitted, into a mapping of subcarrier amplitude and phase. It then transforms this spectral representation of the data into the time domain using an Inverse Discrete Fourier Transform (IDFT). The Inverse Fast Fourier Transform (IFFT) performs the same operations as an IDFT, except that it is much more computationally efficiency, and so is used in all practical systems. In order to transmit the OFDM signal the calculated time domain signal is then mixed up to the required frequency. Block diagram showing a basic OFDM transceiver [3] The receiver performs the reverse operation of the transmitter, mixing the RF signal to base band for processing, then using a Fast Fourier Transform (FFT) to analyze the signal in the frequency domain. The amplitude and phase of the subcarriers is then picked out and converted back to digital data. The IFFT and the FFT are complementary function and the most appropriate term depends on whether the signal is being received or generated. In cases where the Signal is independent of this distinction then the term FFT and IFFT is used interchangeably. [1, 125 -128, 3] Analysis of OFDM characteristics Guard Period OFDM demodulation must be synchronized with the start and end of the transmitted symbol period. If it is not, then ISI will occur (since information will be decoded and combined for 2 adjacent symbol periods). ICI will also occur because orthogonality will be lost (integrals of the carrier products will no longer be zero over the integration period), To help solve this problem, a guard interval is added to each OFDM symbol period. The first thought of how to do this might be to simply make the symbol period longer, so that the demodulator does not have to be so precise in picking the period beginning and end, and decoding is always done inside a single period. This would fix the ISI problem, but not the ICI problem. If a complete period is not integrated (via FFT), orthogonality will be lost. The effect of ISI on an OFDM signal can be further improved by the addition of a guard period to the start of each symbol. This guard period is a cyclic copy that extends the length of the symbol waveform. Each subcarrier, in the data section of the symbol, (i.e. the OFDM symbol with no guard period added, which is equal to the length of the IFFT size used to generate the signal) has an integer number of cycles. Because of this, placing copies of the symbol end-to-end results in a continuous signal, with no discontinuities at the joins. Thus by copying the end of a symbol and appending this to the start results in a longer symbol time. Addition of a guard period to an OFDM signal [3] In Figure 14, The total length of the symbol is Ts=TG + TFFT, where Ts is the total length of the symbol in samples, TG is the length of the guard period in samples, and TFFT is the size of the IFFT used to generate the OFDM signal. In addition to protecting the OFDM from ISI, the guard period also provides protection against time-offset errors in the receiver. For an OFDM system that has the same sample rate for both the transmitter and receiver, it must use the same FFT size at both the receiver and transmitted signal in order to maintain subcarrier orthogonality. Each received symbol has TG + TFFT samples due to the added guard period. The receiver only needs TFFT samples of the received symbol to decode the signal. The remaining TG samples are redundant and are not needed. For an ideal channel with no delay spread the receiver can pick any time offset, up to the length of the guard period, and still get the correct number of samples, without crossing a symbol boundary. Function of the guard period for protecting against ISI [3] Figure 15 shows this effect. Adding a guard period allows time for the transient part of the signal to decay, so that the FFT is taken from a steady state portion of the symbol. This eliminates the effect of ISI provided that the guard period is longer than the delay spread of the radio channel. The remaining effects caused by the multipath, such as amplitude scaling and phase rotation are corrected for by channel equalization. In order to avoid ISI and ICI, the guard period must be formed by a cyclic extension of the symbol period. This is done by taking symbol period samples from the end of the period and appending them to the front of the period. The concept of being able to do this, and what it means, comes from the nature of the IFFT/FFT process. When the IFFT is taken for a symbol period (during OFDM modulation), the resulting time sample sequence is technically periodic. This is because the IFFT/FFT is an extension of the Fourier Transform which is an extension of the Fourier Series for periodic waveforms. All of these transforms operate on signals with either real or manufactured periodicity. For the IFFT/FFT, the period is the number of samples used. Guard Period via Cyclic Extension With the cyclic extension, the symbol period is longer, but it represents the exact same frequency spectrum. As long as the correct number of samples are taken for the decode, they may be taken anywhere within the extended symbol. Since a complete period is integrated, orthogonality is maintained. Therefore, both ISI and ICI are eliminated. Note that some bandwidth efficiency is lost with the addition of the guard period (symbol period is increased and symbol rate is decreased) [2,154-160, 3] Windowing The OFDM signal is made up of a series of IFFTs that are concatenated to each other. At each symbol period boundary, there is a signal discontinuity due to the differences between the end of one period and the start of the next. These discontinuities can cause high frequency spectral noise to be generated (because they look like very fast transitions of the time waveform). To avoid this, a window function (Hamming, Hanning, Blackman, ) may be applied to each symbol period. The window function would attenuate the time waveform at the start and the end of each period, so that the discontinuities are smaller, and the high frequency noise is reduced. However, this attenuation distorts the signal and some of the desired frequency content is lost.[1, 121;2 154] Multipath Characteristics OFDM avoids frequency selective fading and ISI by providing relatively long symbol periods for a given data rate. This is illustrated in Figure 17. For a given transmission channel and a given source data rate, OFDM can provide better multipath characteristics than a single carrier. OFDM vs. Single Carrier, Multipath Characteristic Comparison However, since the OFDM carriers are spread over a frequency range, there still may be some frequency selective attenuation on a time-varying basis. A deep fade on a particular frequency may cause the loss of data on that frequency for a given time, but the use of Forward Error Coding can fix it. If a single carrier experienced a deep fade, too many consecutive symbols may be lost and correction coding may be ineffective. [8] Bandwidth A comparison of RF transmits bandwidth between OFDM and a single carrier is shown in Figure 18 (using the same example parameters as in Figure 17). OFDM Bandwidth Efficiency In Figure 18, the calculations show that OFDM is more bandwidth efficient than a single carrier. Note that another efficient aspect of OFDM is that a single transmitters bandwidth can be increased incrementally by addition of more adjacent carriers. In addition, no bandwidth buffers are needed between transmit bandwidths of separate transmitters as long as orthogonality can be maintained between all the carriers.[2, 161-163; 8; 9] Physical Implementation Since OFDM is carried out in the digital domain, there are many ways it can be implemented. Some options are provided in the following list. Each of these options should be viable given current technology: ASIC (Application Specific Integrated Circuit) ASICs are the fastest, smallest, and lowest power way to implement OFDM Cannot change the ASIC after it is built without designing a new chip General-purpose Microprocessor or MicroController PowerPC 7400 or other processor capable of fast vector operations Highly programmable Needs memory and other peripheral chips Uses the most power and space, and would be the slowest Field-Programmable Gate Array (FPGA) An FPGA combines the speed, power, and density attributes of an ASIC with the programmability of a general purpose processor. An FPGA could be reprogrammed for new functions by a base station to meet future (currently unknown requirements).This should be the best choice.[9] OFDM uses in DVB (Digital Video Broadcasting) DVB (Digital Video Broadcast) is a set of standards for the digital transmission of video and audio streams, and also data transmission. The DVB standards are maintained by the DVB Project, which is an industry-led consortium of over 260 broadcasters, manufacturers, network operators, software developers, regulatory bodies and others in over 35 countries. DVB has been implemented over satellite (DVB-S, DVB-S2), cable (DVB-C), terrestrial broadcasting (DVB-T), and handheld terminals (DVB-H). the DVB standard following the logical progression of signal processing steps, as well as source and channel coding, COFDM modulation, MPEG compression and multiplexing methods, conditional access and set-top box Technology. In this project is presented an investigation of two OFDM based DVB standards, DVB-T and DVB-H. DVB-T (Digital Video Broadcasting Terrestrial) The first Terrestrial Digital Video Broadcasting pilot transmissions were started in the late 90s, and the first commercial system was established in Great Britain. In the next few years the digital broadcasting system has been set up in many countries, and the boom of the digital terrestrial transmission is estimated in the next few years, while the analogue transmission will be cancelled within about 15 years. The greatest advantage of the digital system is the effective use of the frequency spectrum and its lower radiated power in comparison with the analogue transmission, while the covered area remains the same. Another key feature is the possibility of designing a so-called Single Frequency Network (SFN), which means that the neighboring broadcast stations use the same frequency and the adjacent signals dont get interfered. The digital system transmits a data stream, which means that not only television signals but data communication (e.g. Internet service) may be used according to the demands. The data stream consists of an MPEG-2 bit stream, which means a compression is used, enabling the transfer of even 4 or 5 television via the standard 8 MHz wide TV channel. For the viewer, the main advantages are the perfect, noise-free picture, CD quality sound, and easier handling, as well as services like Super Teletext, Electronic Programme Guide, interactivity and mobility.[11, 251-253] Modulation technique in DVB-T The DVB-T Orthogonal Frequency Division Multiplexing (OFDM) modulation system uses multi-carrier transmission. There are 2 modes, the so-called 2k and 8k modes, using 1705 and 6817 carriers respectively, with each carrier modulated separately and transmitted in the 8 MHz TV channel. The common modulation for the carriers is typically QPSK, 16-QAM or 64-QAM. Each signal can be divided into two, so-called „In Phase (I) and „Quadrature Phase components, being a 90Â ° phase shift between them. The constellation diagram and the bit allocation is shown in bellow 16-QAM constellation diagram and bit allocation [6] This modulation can be demonstrated in the constellation diagram, where the 2 axes represent the 2 components (I and Q). In case of using 16-QAM modulation, the number of states is 16, so 1 symbol represents 4 bits. [11, 255; 6; 14] Bir errors If we simulate all the carriers in the constellation diagram we get not just 1 discrete point, but many points, forming a „cloud and representing each state. In case of additive noise the „cloud gets bigger and the receiver may decide incorrectly, resulting in bit errors. Figure 2 shows the measured constellation diagram without and with additive noise. Measured 16-QAM constellation diagram a) without additive noise b) with additive noise [6] To ensure perfect picture quality, the DVB-T system uses a 2 level error correction (Reed-Solomon and Viterbi). This corrects the bad bits at an even 10-4 Bit Error Rate (BER) and enables error-free data transmission. [13, 32-36] The multi-carrier structure The structure of carriers can be illustrated also in the function of time (Figure 20). The horizontal axis is the frequency and the vertical axis is the time. The 8 MHz channel consists of many carriers, placed 4462 Hz or 1116 Hz far from each other according to the modulation mode (2k or 8k). Structure of OFDM carriers [13] There are some reserved, so-called Transmission Parameter Signalling (TPS) carriers that do not transfer payload, just provide transmission mode information for the receiver, so the total number of useful carriers is 1512 and 6048 respectively in the two transmission modes, and the resultant bit rate is between 4,97 and 31,66 Mbit/s, depending on the modulation (QPSK, 16-QAM or 64-QAM), the transmission mode (2k or 8k), the Code Rate (CR) used for error correction and the selected Guard Interval (GI). This guard interval means that there is a small time gap between each symbol, so the transmission is not continuous. This guarding time enables perfect reception by eliminating the errors caused by multipath propagation.[4, 79-90; 13] Frequency spectrum In 2k mode, 1705 carriers are modulated in the 8 MHz TV channel, so each carrier is 4462 Hz far from its neighbor, while in 8k mode this distance is 1116 Hz. In digital broadcasting, there are no vision and sound carriers, so the power for each carrier is the same. This mean