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Linear Programming was conceptually developed before World War II by the outstanding Russian mathematician A.N.Kolmogorov and gained its popularity ever since the development of Simplex method by George B. Dantzig in 1947. Linear programming deals with problems of maximizing or minimizing a linear function in the presence of linear equality and/or inequality constraints. In these problems, we find the optimal, or most efficient way of using limited resources to achieve the objective of the situation. Linear Programming enables users to model large and complex problems and solve in a short amount of time by the use of effective algorithm, hence it is a powerful and widely used tool in various fields such as science, industrial engineering, financial planning and management decision making. Nowadays, with the development of technology, most of the real world Linear Programming problems are solved by computer programs. Excel Solver is a popular one. We work through different examples to demonstrate the applications of linear Programming model and the use of Excel Solver for various decision making in operation and supply chain management.

Components of Linear Programming model

To solve the linear programming problems, we first need to formulate the mathematical description called a mathematical model to represent the situation. Linear programming model usually consists of the following components * Decision variables: These represent the choices that the decision maker can control. For example, the number of items to produce, amounts of money to invest in and so on. The decisions variables are represented using symbols such as X1, X2, X3, ….Xn. * Objective function: The objective of the problem is expressed as a mathematical expression in decision variables. The objective may be maximizing the profit, minimizing…...

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... Get More and Do More at Dummies.com ® Start with FREE Cheat Sheets Cheat Sheets include • Checklists • Charts • Common Instructions • And Other Good Stuff! To access the Cheat Sheet created specifically for this book, go to www.dummies.com/cheatsheet/excelvbaprogramming Get Smart at Dummies.com Dummies.com makes your life easier with 1,000s of answers on everything from removing wallpaper to using the latest version of Windows. Check out our • Videos • Illustrated Articles • Step-by-Step Instructions Plus, each month you can win valuable prizes by entering our Dummies.com sweepstakes. * Want a weekly dose of Dummies? Sign up for Newsletters on • Digital Photography • Microsoft Windows & Office • Personal Finance & Investing • Health & Wellness • Computing, iPods & Cell Phones • eBay • Internet • Food, Home & Garden Find out “HOW” at Dummies.com *Sweepstakes not currently available in all countries; visit Dummies.com for official rules. Excel VBA Programming ® FOR DUMmIES 2ND ‰ EDITION by John Walkenbach Excel® VBA Programming For Dummies®, 2nd Edition Published by Wiley Publishing, Inc. 111 River Street Hoboken, NJ 07030-5774 www.wiley.com Copyright © 2010 by Wiley Publishing, Inc., Indianapolis, Indiana Published by Wiley Publishing, Inc., Indianapolis, Indiana Published simultaneously in Canada No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic,......

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...LINEAR PROGRAMMING Definition. A mathematical technique for solving constrained maximization and minimization problems when there are many constraints and the objective function to be optimized, as well as the constraints faced, are linear (i.e., can be represented by straight lines) Assumptions. -LP is based on the assumption that the objective function that the organization seeks to optimize (maximize or minimize), as well as the constraints that it faces, are linear and can be represented GRAPHICALLY by straight lines. -Input and output prices are constant -Average and marginal costs are constant and equal (they are linear) -Profit per unit is constant; profit function is linear Applications of Linear Programming 1. Optimal process selection 2. Optimal product mix 3. Satisfying minimum product requirements 4. Long-run capacity planning 5. Other specific applications of linear programming Basic Linear Programming Concepts A. Production Process and Isoquants -where a production process or activity can be represented by a straight line ray from the origin in input space B. Optimal Mix of Production Process Procedure Used in Formulating and Solving Linear Programming Problems The steps followed in solving linear programming problem are: 1. Express the objective function of the problem as an equation and the constraints as inequalities. 2. Graph the inequality constraints and define the feasible region. 3. Graph......

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...METHODS/ APPROACH This scheduling problem can be solved most expeditiously using linear programming. Let F denote the number of full-time employ- ees. Some number, F1, of them will work one hour of overtime between 5 PM and 6 PM each day and some number, F2, of the full- time employees will work overtime between 6 PM and 7 PM. There will be seven sets of part-time employees who begin their work day at hour j=j␣1,2,...,7,withP1beingthenumberofworkers beginning at 9 AM, P2 at 10 AM, . . . , P7 at 3 PM. Note that because part-time employees must work a minimum of four hours, none can start after 3 PM because the entire operation ends at 7 PM. Similarly, some number of part-time employees, Qj, leave at the end of hour j, j 4, 5, . . . , 9. The workforce requirements for the first two hours, 9 AM and 10 AM, are: F P1 14 F P1 P2 25 At 11 AM half of the full-time employees go to lunch; the remaining half go at noon. For those hours: 0.5F P1 P2 P3 26 0.5F P1 P2 P3 P4 38 Starting at 1 PM, some of the part-time employees begin to leave. For the remainder of the straight-time day: F P1 P2 P3 P4 P5 −Q4 55 F P1 P2 P3 P4 P5 P6 −Q4 −Q5 60 F P1 P2 P3 P4 P5 P6 P7 −Q4 −Q5 −Q6 51 F P1 P2 P3 P4 P5 P6 P7 −Q4 −Q5 −Q6 −Q7 29 For the two......

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...problem faced and the objectives as laid down by the management group. You may refer to Hillier and Hillier for help in describing the problem. Method used Present the MS method used and why you thought it was the most appropriate amongst other methods. Your justification of the choice is an important part of your assessment Implementation A description of how the raw problem is converted into a spreadsheet model. Please provide details of the raw data and the steps followed for populating it in Excel Analysis Provide alternative solutions and scenarios and their respective outcomes. This should be accompanied by a rationale describing the behaviour of the system as a result of any changes you make to the input values. This is then concluded by an optimisation exercise if required Conclusions The section should provide the final results and justification why this is the best results. The section should include any lessons learned about the system as a result of using this model Marking scheme Grade Requirements Pass (C): A coherent response to the requirements of the assessment task: the report’s overall structure and writing quality is adequate; the reference list is complete (and organised alphabetically in Harvard format); the word limit is not exceeded; evidence of accurate restatement and organisation of relevant concepts, methodology and material appropriate to writing a short report for the lay person. Clarity of the problem statement and the......

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...The development of linear programming has been ranked among the most important scientific advances of the mid 20th century. Its impact since the 1950’s has been extraordinary. Today it is a standard tool used by some companies (around 56%) of even moderate size. Linear programming uses a mathematical model to describe the problem of concern. Linear programming involves the planning of activities to obtain an optimal result, i.e., a result that reaches the specified goal best (according to the mathematical model) among all feasible alternatives. Linear Programming as seen by various reports by many companies has saved them thousands to even millions of dollars. Since this is true why isn’t everyone using Linear Programming? Maybe the reason is because there has never been an in-depth experiment focusing on certain companies that do or do not use linear programming. My main argument is that linear programming is one of the most optimal ways of resource allocation and making the most money for any company today. I used (in conjunction with another field supporter – My Dad) the survey method to ask 28 companies that were in Delaware, New Jersey, and Pennsylvania whether they were linear programming users. In addition, I wanted to examine the effect of the use of linear programming across three different but key decision support areas of the participating companies to include (1) Planning (2) Forecasting and (3) Resource Allocation. The companies were selected randomly from the......

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...1. INTRODUCTION Linear programming, an operations research technique is widely used in finding solutions to complex managerial decision problems. The introduction of linear programming (LP) has produced remarkable benefits in a number of industries. The early experimental applications of LP techniques in the petroleum industry as a refinery management tool had such profound effects that LP is now standard in almost every aspect of that industry. The first application of LP in the textile industry was designed to produce optimal plant efficiency, that is, allocate plant resources to production problems so as to achieve the highest practical return. The purpose of this study is to demonstrate the application of LP model in the blending (mixing) of cotton to produce Acrylic yarn in case of Arbaminch Textile factory. Because the cotton blending process involves complex quality control, it is particularly responsive to LP techniques. In view of today’s technology, the process of cotton fiber selection should undergo an inevitable transition from the traditional pure art to a sound scientific technique. In order to achieve this transition, fiber selection should be integrated into a cotton fiber mixing program that attempts to optimize cotton fiber use with respect to cost and quality of end product. I attempted to examine the practical aspect of linear programming for optimization of cost of producing cotton blended yarn in Arbaminch textile factory without impinging the......

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...Merton Trucks Case Note Abstract We discuss Merton Trucks [Dhe90a] as a case to introduce linear programming in the MBA program. This case adapted from Sherman Motor Company case, was used to introduce Linear Programming formulations as well as duality. Refer to the teaching note [Dhe90b]. Our approach differs from the approach suggested by Dhebar [Dhe90b]. First, our audience consists pre-dominantly of engineers with not too much work experience. As a result, handling math and algebra is relatively easy. Explaining the algebraic formulation, graphical approach and using the Excel solver do not consume that much time. Second, because this case is used during the ﬁrst week of the MBA program, students are still unfamiliar with the case methodology and we spend signiﬁcant time in understanding case facts. The circular logic used in allocating ﬁxed costs based on the product mix that in turn is used in deciding the product mix takes some time to understand. Third, because of the participant background, they have difﬁculty in translating the model to the speciﬁc business situation and interpreting the trade-offs involved in various what-if analyses that are prompted by the case questions. We return to the case when we teach duality. After explaining duality, we analyze the case to show how some of the questions and what-if analyses can be simpliﬁed using duality. This note is based on our experiences with teaching three large batches of students in our MBA programs. 1 1......

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