This research is concerned with the development of effective solutions for the reduction of average cycle time at a wafer fabrication facility. The wafer fabrication environment is quite different from the usual flow shop or job shop environments, with a distinguishing feature being the reentrant flow of the lots through the system. Lots at different stages of their manufacturing cycle may revisit the machines. This gives rise to the need of effective policies to sequence lots through the system. The study is being conducted on a M/A-COM's wafer fabrication system. The facility on which the study is being conducted is based in Roanoke, VA. The facility consists of 92 machines and its products can be classified into six different types. The data required for each product such as routing, processing times, yield at each operation etc. have been acquired from the facility. Two methodologies have been developed to effect a reduction in the cycle time of the products at M/A-COM's facility. The first methodology is heuristic procedure based on the idea of reducing idle time on the bottleneck machine. The second methodology is based on mathematical programming. For the first methodology, the manufacturing system is simulated using AutoSchedAP, which is part of the AutoSimulations Inc. software package. The software enables the accurate modeling of the existing system using actual part routes, station definitions, operator definitions, shift calendars, input orders, machine breakdowns and processing and setup time distributions. The proposed approach, to reduce cycle time, is based on the principle of reduction of idle time at the bottleneck machine. The bottleneck machine controls the throughput of the system and any unnecessary idle time at the bottleneck leads to an increase in the average cycle time. The AutoSchedAP software enables the user to write custom scheduling rules using C++ and integrate it with the simulation model. The performance of the proposed procedure is compared with those of various other scheduling rules in the software. The second proposed methodology models the system as an integer program. The integer program reads the various machine and product data and establishes the optimal flow of the lots through the system. The integer program uses the start time of lots, at various operations, as variables and outputs the time at which each lot should be started at each operation. The integer program is solved using CPLEX, which is a linear and integer programming software. Presently, various methods are being analyzed to relax the integer program into an equivalent linear/nonlinear program, since solving an integer program consumes a lot of time, even for small problems. A third methodology has also been proposed. This methodology concerns the modeling of the system on the basis of a conjunctive-disjunctive graph. The main idea in this methodology is that the minimization of maximum lateness at each operation would result in the minimization of maximum cycle time of the overall system. Some preliminary results obtained are presented. Also, the work in progress is described. / Master of Science

Due to several reasons, such as the competitive environments which entrepreneurs face, new working values, and ideas of outsourcing, companies must have more flexible HRM strategies to maintain the competitive advantages. In order to seek for more flexibility in employment, employee dispatching has become one of the popular ways for companies to use in America, Japan or European countries and so has it in Taiwan. Employee dispatching can help companies to retain professional employees or special techniques, to deal with seasonal demands, to reduce costs and unnecessary managerial responsibilities, so that they can focus more on unclear business. Although employee dispatching brings more flexibility in employment and reduces costs for companies, it still has some complicated issues needed to deal with. The employment relationship is about "joint employer" or "co-employment". This raises complex legal issues especially when related labor laws are not well developed in Taiwan now. Moreover, the quality, loyalty or the performance of dispatched workers is also the problems which companies have to take care of. It is a trend that employee dispatching will be getting more and more popular in Taiwan. Therefore, it is strongly suggested and would be very necessary to do some more advanced studies on the arrangements, the backgrounds of its development, how it is used now, why it is used, what it is going to be in the future, and the compensation of dispatched workers.

Now days in Taiwan, companies are all facing the great stress of competition from global competitors; therefore, every company is looking for solutions of reducing the cost, every aspects of costs. Employment cost is one of the costs. By using dispatching services or by cooperating with dispatch industries, companies shall save more fixed costs of employment, retirement fee for example. For the basic reason mentioned, dispatch industries have become one of the most popular industries, providing dispatch services which fits corporation¡¦s needs of reducing employment costs. In Taiwan, not so much related article were found discuss about what cross-national factor does effect the services that dispatch industries provide differently, and how they appears. Case study will be adopted in the research. We try to sketch the outline of the local dispatching industry through the method and compare the similarities and dissimilarities between dispatching companies that was from different mother nation that provide the same services in Taiwan. From the research, we could conclude that: 1. Employees from different mother nation¡¦s dispatching companies appears no dissimilarities in the aspects of their average age and background; but they do have dissimilarities on their level of education. 2. Dispatching companies from nations other than Taiwan are all having a delicate training system, benefit plan and performance evaluation system than local dispatching companies.

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With the steady declining birth rate in Taiwan, and with the increasing proportion of college students in the population, the main sources of staff of convenience stores are reduced by a wide margin. In addition, constant increase in the number of convenience stores in Taiwan. All these factors cause high flowing rate of staff in the convenience stores and manpower shortage in the convenience stores. Even though every convenience store has been put into sizable resources and diligent workers are recruited, the results are not obvious in a short term. So has the traditional hiring type been already unable to accord with the human resource demand in convenience store? Does employee dispatching become operator's new manpower source and option of convenience stores? The employee dispatching has been prevailing in other countries for many years, and the advantages and drawbacks of employee dispatching have been widely studied, both domestically and internationally, via enterprises that use employee dispatching. But could these advantages and drawbacks also appear in every industry when the employee dispatching is used? Could convenience stores use employee dispatching to solve the problems in human resource? This study gets the present human recruit predicament, and understand every leaguer¡¦s cognition of topic to employee dispatching. We use in-depth interview, interviewing the shop managers with outstanding performance, to study that if dispatching industry are suitable for the industry of convenience stores, to provide the reference basis for the dispatching industry proprietors when they consider entering the industry of convenience stores, and also to offer useful relevant information to future studies. Originally discover: 1. It is ubiquitous that the manpower recruited problem of convenience stores, even if the national remarkable shop managers are long and no exception. 2. It belongs to more general impressions to the cognition that employee dispatching to the leaguers of convenience stores, but for dispatched worker's doubt to be higher than (the employee dispatching) its advantage (that) far. 3. Leaguers will have the cognitive much genera of advantage to expect to employee dispatching, but can not cut the true basis. 4. Leaguers have cognitive of employee dispatching shortcoming is it reverse side influence that dispatched worker might bring and to injury that retail operation. 5. Leaguers are that full of more doubt to employee dispatching, but they still have full expect to that it might solve to manpower problem in the retail operation. 6. Employee dispatching is present unsuitably in the convenience store industry.

Truckload shipments constitute a significant portion of the freight transportation industry. In recent years, truckload industry is facing a serious problem of high driver turn over rate. In this research, we present a mathematical model for multi-zone dispatching method to solve this issue. Multi-zone dispatching is a method in which a service area is divided into many zones. Truckload within a zone is carried by local drivers and the truckload between zones is carried by lane drivers. Apart from reducing the driver tour length to a desirable level, the model for multi-zone also contains some unique constraints to address some issues from the perspectives of the company and the customer. The binary integer program is solved by exact methods. As the problem size increases, exact methods fail quickly. Hence, a construction heuristic within tabu search framework is developed to solve the model. Analysis of various parameters concerned is provided to gain better insights of varied aspects of the problem. Computational results for analysis of parameters and comparison of exact and heuristic methods are provided.

Truckload shipments constitute a significant portion of the freight transportation industry. In recent years, truckload industry is facing a serious problem of high driver turn over rate. In this research, we present a mathematical model for multi-zone dispatching method to solve this issue. Multi-zone dispatching is a method in which a service area is divided into many zones. Truckload within a zone is carried by local drivers and the truckload between zones is carried by lane drivers. Apart from reducing the driver tour length to a desirable level, the model for multi-zone also contains some unique constraints to address some issues from the perspectives of the company and the customer. The binary integer program is solved by exact methods. As the problem size increases, exact methods fail quickly. Hence, a construction heuristic within tabu search framework is developed to solve the model. Analysis of various parameters concerned is provided to gain better insights of varied aspects of the problem. Computational results for analysis of parameters and comparison of exact and heuristic methods are provided.

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No description available.