Dissertations/Theses - Department of Industrial and Production Engineering

Browse

Filters

20072

Settings

End date: 2009Subject: search.filters.subject.Fuzzy sets - Industrial problem

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Heuristic optimization algorithm based line balancing in a fuzzy environment
    (Department of Industrial and Production Engineering, BUET, 2007-04) Ferdous Sarwar; Hasin, Dr. M. Ahsan Akhtar
    A,sembly Line Balancing (ALB) is one of the important problems of production management. As small improvemcnts in the performance of the ,ystem can lead to significant monetary consequences, it is of utmost importance to develop practical solutIon proccdures that yield high-quality design decisions wlth milllmal computalional requirements. Due to the NP-hard nature of the ALB problem, heuri5tlcs are gencrally used to solve rcallifc problems. The constraints and paranleters of fuzlY natllre exist in lme balancing problem,. Fuay optimization can be implemented effectively in solving ASLBP. Fuay sets or funy numbers can appropriatcly reprc~ent imprecisc paramcters, and can be mampulatcd through dilTerent operations on fuzzy ~etsor fuzzy numbers. Since imprecise parameters are trcaled as imprecise valucs instead of precise ones, the proccss will be more powerful and its results more credible. An cnieient heuristic to solve the tilzzy single-model ALB problem has been presented in this research work. The propo5ed heunstie is a Genetic Algorithm (GAl with a special chromosome structure that is efficient to handle fuz'l.yjob lime through the evolution process. Elitism is also implemented in the moJel by usmg illness function value. In this contcxt, the proposed approach can be viewed as a unified framework which combines sevcral new concepts of GA in the algorithmic design.
  • Thumbnail Image
    Item
    Fuzzy multi objective machine reliability based hybrid flow shop scheduling
    (Department of Industrial and Production Engineering, BUET, 2007-01) Tahmina Ferdousi Lipi; Hasin, Dr. M. Ahsan Akhtar
    Many real-world schcduling problems are multi objGctlve and complex in nature, ThaI is, there e>."l scvcral critena lilal must be laken into consideralion when evaluatmg thc quality of thc proposed solullon or schedule. On the other hand consideration of machine rehabilit y is vcry important dllring job allocatioo in each stage to get a realistIC hyhrid flow shop ~chcdulc. This research aims to develop 1'1.'0fuzzy infercnee systems (F1S) fDr the hybrid flow ~hop pwblem, Fir~t FIS is used tD gel the priority of each jDh considering multiple objectives of proces5ing time, duc date and co;t over time. Second FIS is used tQ get machine rehabiIity and availability based priorily using lhe infomlalion of mean time to failure (MTTF) & mcan time to repair (MTTR) of each individual machine of each ~tage. Then the total load is balanced depcnding on !heir reliability and availabl1ity i.e., maximum utili,alion target are detenmlled. An algorithm is developed for grouping, sequencing & aIIDcating the JDbs to the machmes at every stage in such a way lhat tolal percentage Df over utilization is minimllJll. Accmding to this algorithm a cDmputing tDol;s developed and w,lh a case study the entire process i, explained,