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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Improved optimality conditions for the Wagner-Whitin algorithm.

January 1988 (has links)
by Ha Yiu Cheung, Albert. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1988. / Bibliography: leaves 90-94.
12

On the single level capacitated lot sizing problem.

January 1998 (has links)
Yip Ka-yun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 107-113). / Abstract also in Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Overview --- p.1 / Chapter 1.2 --- Our Contributions --- p.2 / Chapter 1.3 --- Organization of the Thesis --- p.4 / Chapter Chapter 2 --- Literature Review --- p.5 / Chapter 2.1 --- Overview --- p.5 / Chapter 2.2 --- Research in Capacitated Lot Sizing Problem without significant setup times --- p.5 / Chapter 2.3 --- Research in Capacitated Lot Sizing Problem with setup time consideration --- p.12 / Chapter 2.4 --- Summary --- p.15 / Chapter Chapter 3 --- Capacitated Lot Sizing Problem with Setup Times --- p.16 / Chapter 3.1 --- Overview --- p.16 / Chapter 3.2 --- Problem Description and Formulation --- p.20 / Chapter 3.2.1 --- Our problem formulation / Chapter 3.2.2 --- Comparison between our problem formulation and traditional problem formulation / Chapter 3.3 --- Description of the Algorithm --- p.26 / Chapter 3.3.1 --- Wagner-Whitin algorithm / Chapter 3.3.2 --- Transportation problem / Chapter 3.3.3 --- Consistence test / Chapter 3.3.4 --- Subgradient optimization / Chapter 3.3.5 --- Computation of lower bound / Chapter 3.4 --- Design of Experiment --- p.43 / Chapter 3.4.1 --- Product demands / Chapter 3.4.2 --- Setup costs / Chapter 3.4.3 --- Setup times / Chapter 3.4.4 --- Capacity costs / Chapter 3.4.5 --- Inventory holding costs / Chapter 3.4.6 --- Quantity of capacity available for production / Chapter 3.4.7 --- Capacity absorption rate / Chapter 3.4.8 --- Generation of larger problems / Chapter 3.4.9 --- Initialization of Lagrangean multipliers / Chapter 3.4.10 --- Close test / Chapter 3.5 --- Open test --- p.58 / Chapter 3.6 --- Managerial Implications --- p.61 / Chapter 3.7 --- Summary --- p.61 / Chapter Chapter 4 --- Capacitated Lot Sizing Problem without Setup Times --- p.63 / Chapter 4.1 --- Overview --- p.63 / Chapter 4.2 --- Problem Description and Formulation --- p.64 / Chapter 4.3 --- Description of the Algorithm --- p.67 / Chapter 4.3.1 --- Decomposition scheme / Chapter 4.3.2 --- Wagner-Whitin algorithm / Chapter 4.3.3 --- Transportation problem / Chapter 4.3.4 --- Subgradient optimization / Chapter 4.3.5 --- Computation of lower bound / Chapter 4.4 --- Design of Experiment --- p.80 / Chapter 4.4.1 --- Product demands / Chapter 4.4.2 --- Setup costs / Chapter 4.4.3 --- Capacity costs / Chapter 4.4.4 --- Inventory holding costs / Chapter 4.4.5 --- Quantity of capacity available for production / Chapter 4.4.6 --- Capacity absorption rate / Chapter 4.4.7 --- Generation of larger problems / Chapter 4.4.8 --- Initialization of Lagrangean multipliers / Chapter 4.4.9 --- Selection of the extent of geometrical reduction and exponential smoothing / Chapter 4.4.10 --- Close test / Chapter 4.5 --- Open test --- p.92 / Chapter 4.6 --- Managerial Implications --- p.95 / Chapter 4.7 --- Comparison with other approaches --- p.96 / Chapter 4.7.1 --- Gilbert and Madan's approach / Chapter 4.7.2 --- Our algorithm for CLS problem with setup time consideration / Chapter 4.8 --- Summary --- p.102 / Chapter Chapter 5 --- Conclusion --- p.104 / Appendix A Vogel's approximation method --- p.106 / Bibliography --- p.107
13

Material flow system integration in EOQ, ELSP, and Kanban production environments /

Choi, Soodong, January 1998 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 198-208). Also available on the Internet.
14

Material flow system integration in EOQ, ELSP, and Kanban production environments

Choi, Soodong, January 1998 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 198-208). Also available on the Internet.
15

Multi-level lot size strategy performance and selection in a material requirements planning system /

Collier, David A. January 1978 (has links)
No description available.
16

Lot sizing in multi-level multi-echelon inventory system

Birla, Ajay January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
17

Optimering och balansering av cyklisk produktion : En studie på Sandvik Materials Technology PU Borrstål

Hedlund, Tommy, Kvarnlöf, Daniel January 2016 (has links)
Aim: The purpose of this study is to present and test an algorithm that gives acceptable solutions in the optimization of a dedicated production line consisting of several machines, with regards of inventory holding cost and available capacity. The aim is also to suggest possible improvements in the practical case that has been used to test the model, which have been made in cooperation with Sandvik Materials Technology and it’s product unit Rock Drill Steel, located in Sandviken, Sweden. Method: An algorithm has been elaborated from articles and science reports and has then been tested with data from the practical case. The result has then been evaluated through an analysis where the algorithm’s ability to acceptable solutions and show potential savings with regards to capital tied up in stock of finished products, safety stock and products in work in process. Results and conclusions: The study shows that the algorithm has the ability to create acceptable solutions when given a specific demand rate, cycle time and capacity. The study also shows potential savings when using a shorter production cycle, given that the unit works in a structured way in order to shorten the production cycle. Suggestions for future research: The algorithm tested in this study needs more evaluations regarding its limits and possible benefits through practical and theoretical case studies. Contributions: The algorithm the possibility to combine principles and models aimed at solving the ELSP (Economic Lot Schedule Problem) and the principles of Schedule Leveling, which is a common term in lean production to a model that optimize inventory holding costs. These theories have similar approaches to cyclic production, but have different aims. Key words: cyclic scheduling, ELSP, economic lot size problem, schedule leveling, heijunka, lean production / Titel: Optimering och balansering av cyklisk produktion - en studie på Sandvik Materials Technology PU Borrstål Nivå: C-uppsats i ämnet Industriell Ekonomi Författare: Tommy Hedlund, Daniel Kvarnlöf Handledare: Mohammad Abid Datum: 2016 - Mars Syfte: Studiens syfte är att presentera och testa en algoritm som ger godkända resultat vid optimering av en dedikerad produktionslina bestående av flera produktionsresurser, med avseende på lagerhållningskostnad i omsättningslager samt tillgänglig kapacitet, samt att presentera möjliga förbättringsförslag utifrån de resultat som ges i det praktiska fall som simuleringsmodellen utvärderas genom. Det praktiska fallet i denna studie är Sandvik Materials Technology och dess produktenhet Borrstål. Metod: Studien har genomförts genom att en algoritm har tagits fram utifrån artiklar och forskningsrapporter på området, som sedan har prövats mot studiens praktiska fall. Resultatet har sedan utvärderats genom en analys av algoritmens förmåga att ge godkända lösningar, samt möjlig besparingspotential i det aktuella fallet utifrån kapitalbindning i omsättningslager, säkerhetslager och produkter i arbete. Resultat & slutsats: Studien visar att algoritmen har en god förmåga att skapa godkända resultat utifrån en specifik efterfrågan, cykeltid och kapacitet. Studien visar även på stora potentiella besparingar i kapitalbindning till följd av kortare cykeltid i såväl omsättningslager, säkerhetslager och produkter i arbete, givet att produktenheten arbetar strukturerat med att söka minska cykeltiden. Förslag till fortsatt forskning: Algoritmen behöver ytterligare forskning kring dess begränsningar genom att utvärderas utifrån fler praktiska och teoretiska fall. Uppsatsens bidrag: Algoritmen visar på en möjlighet att kombinera ELSP (economic lot scheduling problem) och dess modeller med de principer som återfinns inom Schedule Leveling, som är ett vanligt begrepp inom lean production. Dessa teorier liknar varandra men har till viss del skilda syften, vilka kan kombineras till en modell som optimerar produktionen med avseende på lagerhållningskostnaderna.
18

Heuristic strategies for the single-item lot-sizing problem with convex variable production cost

Liu, Xin, 劉忻 January 2006 (has links)
published_or_final_version / abstract / Industrial and Manufacturing Systems Engineering / Master / Master of Philosophy
19

A genetic algorithm for the capacitated lot sizing problem with setup times.

January 2009 (has links)
Chen, Jiayi. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (p. 86-94). / Abstract also in Chinese. / Abstract --- p.i / Acknowledgement --- p.iv / Introduction --- p.1 / Chapter 1.1 --- Introduction to the Capacitated Lot Sizing (CLS )problem --- p.1 / Chapter 1.2 --- Our contributions --- p.2 / Chapter 1.3 --- Organization of the thesis --- p.4 / Literature Review --- p.5 / Chapter 2.1 --- Research in CLS problem --- p.5 / Chapter 2.1.1 --- Reviews in CLS problems --- p.8 / Chapter 2.1.2 --- Approaches and methods to solve the traditional CLS problems --- p.9 / Chapter 2.1.3 --- Research on Fixed-Charge-Transportation-typed models for CLS problems --- p.13 / Chapter 2.2 --- Research in Genetic Algorithm (GA) --- p.15 / Chapter 2.3 --- Conclusion --- p.17 / Problem Description and Formulation --- p.18 / Chapter 3.1 --- The formulation --- p.18 / Chapter 3.2 --- Comparison with the traditional formulation --- p.24 / Chapter 3.3 --- Conclusion --- p.28 / Description of the Heuristic --- p.29 / Chapter 4.1 --- Initialization --- p.32 / Chapter 4.1.1 --- Setup string generation --- p.32 / Chapter 4.1.2 --- Transportation problem --- p.35 / Chapter 4.1.3 --- Consistency test --- p.47 / Chapter 4.2 --- Selection --- p.50 / Chapter 4.3 --- Crossover --- p.50 / Chapter 4.4 --- Mutation --- p.52 / Chapter 4.5 --- Evaluation --- p.53 / Chapter 4.6 --- Termination --- p.54 / Chapter 4.7 --- Conclusion --- p.54 / Design of Experiments and Computational Results --- p.56 / Chapter 5.1 --- Design of experiments --- p.57 / Chapter 5.2 --- Discussion of lower bound procedures --- p.63 / Chapter 5.3 --- Computational results --- p.65 / Chapter 5.3.1 --- CLS problems with setup times --- p.65 / Chapter 5.3.2 --- CLS problems without setup times --- p.77 / Chapter 5.4 --- Conclusion --- p.82 / Conclusion --- p.83 / Bibliography --- p.86
20

Lot-sizing and inventory routing for a production-distribution supply chain

Nananukul, Narameth, 1970- 29 August 2008 (has links)
The integration of production and distribution decisions presents a challenging problem for manufacturers trying to optimize their supply chain. At the planning level, the immediate goal is to coordinate production, inventory, and delivery to meet customer demand so that the corresponding costs are minimized. Achieving this goal provides the foundations for streamlining the logistics network and for integrating other operational and financial components of the system. In this paper, a model is presented that includes a single production facility, a set of customers with time varying demand, a finite planning horizon, and a fleet of vehicles for making the deliveries. Demand can be satisfied from either inventory held at the customer sites or from daily product distribution. A procedure centering on a reactive tabu search is developed for solving the full problem. After a solution is found, path relinking is applied to improve the results. A novel feature of the methodology is the use of an allocation model in the form of a mixed integer program to find good feasible solutions that serve as starting points for the tabu search. Lower bounds on the optimum are obtained by solving a modified version of the allocation model. Computational testing on a set of 90 benchmark instances with up to 200 customers and 20 time periods demonstrates the effectiveness of the approach. In all cases, improvements ranging from 10 - 20% were realized when compared to those obtained from an existing greedy randomized adaptive search procedure (GRASP). This often came at a three- to five-fold increase in runtime, however. A hybrid scheme that combines the features of reactive tabu search algorithm and branch-and-price algorithm is also developed. The combined approach takes advantage of the efficiency of the tabu search heuristic and the precision of the branch-and-price algorithm. Branching strategy that is suitable for the problem is proposed. Several advance techniques such as column generation heuristic and rounding heuristic are also implemented to improve the efficiency of the algorithm. Computational testing on standard data sets shows that a hybrid algorithm can practically solve instances with up to 50 customers and 8 time periods which is not possible by standard branch-and-price algorithm alone. / text

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