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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.
71

Design of Cellular Manufacturing Systems for Dynamic and Uncertain Production Requirements with Presence of Routing Flexibility

Mungwattana, Anan 15 September 2000 (has links)
Shorter product life-cycles, unpredictable demand, and customized products have forced manufacturing firms to operate more efficiently and effectively in order to adapt to changing requirements. Traditional manufacturing systems, such as job shops and flow lines, cannot handle such environments. Cellular manufacturing, which incorporates the flexibility of job shops and the high production rate of flow lines, has been seen as a promising alternative for such cases. Although cellular manufacturing provides great benefits, the design of cellular manufacturing systems is complex for real-life problems. Existing design methods employ simplifying assumptions which often deteriorate the validity of the models used for obtaining solutions. Two simplifying assumptions used in existing design methods are as follows. First, product mix and demand do not change over the planning horizon. Second, each operation can be performed by only one machine type, i.e., routing flexibility of parts is not considered. This research aimed to develop a model and a solution approach for designing cellular manufacturing systems that addresses these shortcomings by assuming dynamic and stochastic production requirements and employing routing flexibility. A mathematical model and an optimal solution procedure were developed for the design of cellular manufacturing under dynamic and stochastic production environment employing routing flexibility. Optimization techniques for solving such problems usually require a substantial amount of time and memory space, therefore, a simulated annealing based heuristic was developed to obtain good solutions within reasonable amounts of time. The heuristic was evaluated in two ways. First, different cellular manufacturing design problems were generated and solved using the heuristic. Then, solutions obtained from the heuristic were compared with lower bounds of solutions obtained from the optimal solution procedure. The lower bounds were used instead of optimal solutions because of the computational time required to obtain optimal solutions. The results show that the heuristic performs well under various circumstances, but routing flexibility has a major impact on the performance of the heuristic. The heuristic appears to perform well regardless of problem size. Second, known solutions of two CM design problems from literature were used to compare with those from the heuristic. The heuristic slightly outperforms one design approach, but substantially outperforms the other design approach. / Ph. D.
72

Application of the interface analysis template for delivering system requirements

Uddin, Amad, Campean, Felician, Khan, M. Khurshid 22 June 2016 (has links)
yes / This paper presents a structured approach for systems requirements analysis that integrates use case modelling with a coherent flows based approach for describing interface exchanges based on the Interface Analysis Template. The approach is discussed in the context of current frameworks for requirements elicitation from the engineering design and systems engineering domains, and it is illustrated with an automotive case study. This illustrates the strength of the framework to support structured multi-domain and multi-disciplinary analysis of requirements for complex systems.
73

Tools and Techniques for Effective Distributed Requirements Engineering: An Empirical Study

Lloyd, Wes J. 30 July 2001 (has links)
Software development teams are often geographically distributed from their customers and end users. This creates significant communication and coordination challenges that impact the effectiveness of requirements engineering. Travel costs, and the local availability of quality technical staff increase the demand for effective distributed software development teams. In this research an empirical study was conducted on the application of groupware to facilitate the requirements phase of the software engineering life cycle. The study considered the impact of the distributed work environment on requirements engineering process quality, as well as the effectiveness of requirements elicitation techniques when used in the distributed setting. Through the examination of the effectiveness of groupware tools, and requirements elicitation techniques, customer participation is found to be paramount for distributed requirements engineering. As requirements negotiation becomes more asynchronous in nature, it appears that customer participation in the elicitation process becomes very important for process effectiveness. Verbal communication barriers negatively effect customer participation. Such barriers cause customers to rely upon mediums such as email and text chat that are very good at reducing social distance, but are less rich in informational content. / Master of Science
74

Variations of Water and Dry Matter in the Leaves of Pima and Acala Cotton

Hawkins, R. S. 01 November 1927 (has links)
This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.
75

DEVELOPMENT OF A REQUIREMENTS REPOSITORY FOR THE ADVANCED DATA ACQUISITION AND PROCESSING SYSTEM (ADAPS)

Rush, David, Hafner, F. W. (Bill), Humphrey, Patsy 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Standards lead to the creation of requirements listings and test verification matrices allow developer and acquirer to assure themselves and each other that the requested system is actually what is being constructed. Further, in the intricacy of the software test description, traceability of test process to the requirement under test is mandated so the acceptance test process can be accomplished in an efficient manner. In the view of the logistician, the maintainability of the software and the repair of fond faults is primary, while these statistics can be gathered by the producer to ultimately enhance the Capability Maturity Module (CMM) rating of the vendor.
76

Time Based Requirements and Partitioning of Systems with Automatic Test Case Generation

Ewing, Tony January 2008 (has links)
Automatic test case generation is a process that starts with text based functional requirements which are converted to a formal system requirements model. Once the formal system requirements model is created the automatic test case generation software creates a set of test scenarios that will verify that the requirements are all met. The automatic test case generation software accomplishes the conversion in a four step process: create base scenarios, identify unverified requirements, enhance scenarios to cover all requirements and allow black box testing, and then combine the scenarios into a single scenario tree. The automatic test case generation system outputs a set of scenarios by walking the final scenario tree. This dissertation expands on automatic test case generation for embedded systems in two major ways. The first is to extend functional automatic test case generation to allow for time based requirements as first class objects. The second is to use the automatic test case generation system to enable system partitioning decisions. The addition of time based requirements to the automatic test case generation system allows more complex systems to be developed. By providing a partitioning recommendation based on the test cases generated from the system requirements, the scope and capabilities of a single designer can be expanded to more complex systems. The resulting upgrades to the theory of automatic test case generation could be applied to the existing tools or incorporated in modern UML/SysML based design tools.
77

Vegetative physiology of cotton as related to the Crop Water Stress Index

Alou, Abdourahamane, 1959- January 1989 (has links)
This study was undertaken to investigate Gossypium hirsutum L. reproductive physiology and metabolic activities as they relate to the Crop Water Stress Index. Five treatments were established based on the CWSI. These were the maximum stress levels allowed for each treatment. The indices investigated were .16, .35, .36, .40, and .62. Daily tagging of opened flowers in each treatment was conducted throughout the season. Diffusive resistance, transpiration, apparent photosynthesis, and yield were measured. There was no significant difference in treatment yield. Plants irrigated at stress level either below .30 or above .40, tended to yield relatively low compared to plants maintained between .30 and .40. Floral production, abscission and boll retention were negatively correlated to CWSI. Negative relationships were also found between apparent photosynthesis, transpiration, leaf area and CWSI. A two day lag response was observed between a decrease in CWSI values resulting from irrigation, and daily flowering increase.
78

The implications of new developments in technology on searching habits in a chemical company

Smith, Elaine Mary Davis January 1991 (has links)
No description available.
79

Bribery, shaming, threat and virtue : a comparison of historic and current influences on resource allocation and policy development in protected areas in Canada and Scotland

Hedges, Peggy L. January 2000 (has links)
This study seeks to understand how agencies with strict land use requirements and plan formulate and translate land use objectives into budgets and spending priorities. Characteristics such as legislation, policy and management body structure were examined alongside various influences to determine the extent to which these decision processes are impacted and provide insight into how such influences may be usefully levered and potentially transferred to other situations. In particular, the research was focussed on some of the "drivers" to the budgeting and land use prioritising processes. It is often argued that objectives are established in the annual business or corporate plan for the area and the budget follows this. However the intention of the research is to show that finances do indeed affect achieving the objectives but not in a direct cost manner. The research is primarily qualitative given the nature of what was being evaluated; the discrepancy between the offici al view of what should be, and what is taking place from the decision makers view was brought to light through a study of the intervening processes. This study strongly suggests that, although the organisational structures and administrative processes have substantially changed and evolved over the past twenty years resulting in today's Parks Canada and Scottish Natural Heritage, the tools used by these agencies to translate land use objectives into budgets and spending priorities have not. As a result, external influences that could be anticipated and planned for are excluded along with recognition of any potential benefits these influences could bring. Further, efforts to facilitate collaborative management have had only limited successes due on the most part to the constituent authorities using these antiquated tools and the lack of a meaningful evaluation process to measure the success of collaborative management efforts. That is budgeting and planning/resource allocation processes do not reward or encourage collaboration and may, in fact, inhibit such efforts at a management level.
80

Implementing material requirements planning in a distribution environment to manage and control the material more effectively.

Job, M. A. January 1994 (has links)
UNIVERSITY OF THE WITWATERSRAND, JOHANNESBURG SCHOOL OF MECHANICAL ENGINEERING PROJECT REPORT FOR DEGREE OF MASTERS 0F SCIENCE IN ENGINEERING (INDUSTRIAL). / Pretoria Distributor, one of Eskom's five main distributors, was experiencing several problems with the management and planning of their electrification projects. The problems occurred as a result of inadequate systems, processes and training. The rapid increase in the volume of material that had to be managed necessitated them to investigate the possibility of implementing Materials Requirements Planning. The investigation highlighted the fact that it would be very difficult to handle the volume of projects on the current systems, [i.e. base systems) and while the environment at the Distributor is not ideally suited to MRP, they should still enjoy many of the benefits of implementing MRP. In preparing for the implementation, several action plans had to be put in place to address the problems of poor planning. By the time the Distributor was "live" on MRP many of the earlier problems relating to planning and design standards, had been addressed. 'the pest implementation evaluation revealed that although the electrification projects was not an ideal environment in which to run MRP, they were enjoying several benefits from the implementation. / Andrew Chakane 2018

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