Abstract For the past few years, electronics manufacturing may have been the victim of its own success. Unlike in heavier industries, rationalization is a concept that was unknown in the sector until only a few years ago and even now, many companies are struggling with cost-cutting measures. Production systems in electronics manufacturing need to be highly flexible because of a varying and evolving environment. Therefore real-time process control and, possibly as a result, production optimization are extremely challenging areas. Traditional approaches often do not work due to a lack of robustness or reliability. For this reason, a new generation of decision support systems is needed in response to some specific problems. The thesis addresses topics such as design of intelligent interfaces for knowledge acquisition and elicitation, use of that knowledge for improved data analysis and diagnostics, real-time feedback control, self-tuning capabilities, and evaluation of optimization methods in discrete processes. Topics covered therefore include the whole scope of a decision support system, from its design through to the evaluation of its performance as well as interaction capabilities as a vehicle for sharing information. The aim of this research is to streamline the development of a new generation of decision support systems by providing tools and methods for a better integration of knowledge in an evolving environment. The main interest lies not only in improved data analysis, but also in better formalization and use of diagnosis. Case studies presented in this thesis demonstrate the practical feasibility of such an approach.

The goal of this dissertation is to study optimization models that integrate location, production, inventory and transportation decisions for industrial products and apply the knowledge gained to develop supply chains for agricultural products (biomass). We estimate unit cost for the whole biomass-to-biofuels’ supply chain which is the per gallon cost for biofuels up till it reaches the markets. The unit cost estimated is the summation of location, production, inventory holding, and transportation costs. In this dissertation, we focus on building mathematical models for designing and managing the biomass-to-biofuels’ supply chains. The computational complexity of the developed models makes it advisable to use heuristic solution procedures. We develop a Lagrangean decomposition heuristic. In our heuristic, we divide the problem into two sub-problems, sub-problem 1 is a transportation problem and sub-problem 2 is a combination of a capacitated facility location and production planning problem. Subproblem 2 is further divided by commodities. The algorithm is tested for a number of different scenarios. We also develop a decision support system (DSS) for the biomass-to-biofuels’ supply chain. In our DSS, the main problem is divided into four easy-to-solve supply chain problems. These problems were determined based on our knowledge of supply chain and discussions with the experts from the biomass and biofuels’ sector. The DSS is coded using visual basic applications (VBA) for Excel and has a simple user interface which assists the user in running different types of supply chain problems and provides results in form of reports which are easy to understand.

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No description available.

Design frequently involves a series of trade-offs to obtain the "optimal" solution to a design problem. Green roofs have many different characteristics based on a variety of variables. Designers typically weigh the impacts of these characteristics in an implicit process based on intuition or past experience. But since vegetated roofing is a relatively complex and comparatively new technology to many practitioners, a rational, explicit method to help organize and rank the trade-offs made during the design process is useful. This research comprises the creation of a framework diagramming the decision process involved in the selection of vegetated roofing systems. Through a series of expert interviews and case studies, the available knowledge is captured and organized to determine the critical parameters affecting design decisions. A set of six case study projects in North America is analyzed and six critically important evaluative categories are identified: storm water management, energy consumption, acoustics, structure, compliance with regulatory guidelines and governmental incentives, and cost. These six factors are key decision-making parameters in the selection of vegetated roofing systems and they form the basis of this study. They are addressed in the context of a decision support system for green roof designers. A summation of the total importance of the advantages represented by each alternative is used to determine the most feasible green roof system for a particular project. The decision-making framework developed in this dissertation will ultimately be adaptable to digital processing and a computer-based design assistance tool. / Ph. D.

Failure of pipes in water distribution systems is a common occurrence especially in large cities. The failure of a pipe results in: loss of water; property damage; interruption of service; decreased system performance; and the financial cost of restoring the failed pipe. The cost of replacement and rehabilitation in the United States is estimated at 23 plus billion dollars. It is virtually impossible to replace all vulnerable pipes at the same time. As a result, there is a need for methods that can help in progressive system rehabilitation and replacement subject to budgetary constraints. If delaying is considered a good strategy due to the time value of money then, the timing of preventive maintenance becomes a crucial element for system maintenance and operation. The central under pinning element in the decision process for scheduling preventive maintenance is the deteriorating nature of a pipe under a given surrounding. By planning to replace pipes before they fail, proper planning can be put in place for securing of finances and labor force needed to rehabilitate the pipes. With this approach, service interruptions are minimized as the loss of service time is limited to the time used in replacing the pipe. In this research, a mechanistic model for assessing the stage of deterioration of an underground pipe is developed. The developed model consists of three sub-models namely, the Pipe Load Model (PLM), the Pipe Deterioration Model (PDM), and the Pipe Break Model (PBM). The PLM simulates the loads and stresses exerted on a buried water main. These loads include the earth load, traffic load, internal pressure, expansive soil loads, thermal, and frost loads. The PDM simulates the deterioration of the pipe due to corrosion resulting from the physical characteristics of the pipe environment. The pipe deterioration effect is modeled in two stages. First, the thinning of the pipe wall is modeled using a corrosion model. Second, the localized pit growth is used to determine the residual strength of the pipe based on the fracture toughness and the initial design strength of the pipe. The PBM assesses the vulnerability of a pipe at any time in terms of a critical safety factor. The safety factor is defined as the ratio of residual strength to applied stress. For a conservative estimate the multiplier effect due to thermal and frost loads are considered. For a chosen analysis period, say 50 years, the pipes with safety factors less than the critical safety factor are selected and ordered by their rank. Aided by the prioritized list of failure prone pipes, utilities can organize a replacement schedule that minimizes cost over time. Additionally a physically based regression model for determining the optimal replacement time of pipe is also presented. A methodology for assessing the consequences of accelerated and delayed replacement is also provided. The methodologies developed in this dissertation will enable utilities to formulate future budgetary needs compatible with the intended level of service. An application of the model and results are included in the dissertation. / Ph. D.

TEAMDEC is a Group Decision Support System (GDSS). The development of a GDSS is supported by a broad spectrum of theories and techniques. Two major aspects of GDSS development were considered in TEAMDEC design: HCI and decision-making assistance. These two aspects interact to promote an interactive group decision support system with high quality. Decision guidance using a script-based knowledge representation improves the GDSS's efficiency, effectiveness, and flexibility. The traditional script, however, is relatively inflexible. The proposed application, TEAMDEC, provides a set of solutions to support customization in a script system to enhance the decision guidance utilization. The user interface design plays an important role in the overall system design. Two software development models (lifecycle model and V-model with backtracking) are adopted for TEAMDEC development. The user interface design of TEAMDEC is considered from three perspectives: functional, aesthetic, and structural. Quality is emphasized in the development of the interactive system. It can be measured from two perspectives: those of the user and the designer. The quality measures of TEAMDEC are categorized into external properties and internal properties, corresponding to the two perspectives. / Master of Science

Federal, state and private organizations have an urgent need for renewal of water and wastewater pipelines. A pertinent gap remains in understanding the relationship between deteriorated host-pipe conditions and renewal products cost and performance. This work provides a framework Decision-Support System that supports water and wastewater pipeline renewal-products. Various renewal products fit utility needs, and the optimization of this process streamlines the decision-making for renewal product selection. The Thesis has classified various factors for use in the renewal product decision-making process, and it provides the justification for use of the renewal decision-making factors in recommending a product. Pipeline problem definition, system causes, system requirements and renewal product characteristics are the key decision-making areas controlling the recommendation of a renewal product. The Decision-Support System framework is developed in a user-friendly Visual Basic forms, using Microsoft tools and evaluated for vendor information. The given framework allows the user to edit product information needs, factors affecting decision-making and the classification of each factor. This allows for ease in modification, utilization and collaborative understanding. The prototype framework An online hosting of the proposed framework will improve accessibility and validity of the renewal decision-making process. / Master of Science

Informed decision making is part of any successful organization. Decision support systems help organizations to make more educated decisions by assisting decision makers in consolidating and analyzing information. Successfully introducing decision support systems is very challenging and risky because many factors need to be taken into account. In this thesis, structured and semi-structured interviews are carried out with employees at a Nordic construction company to discuss critical success factors in connection to introduction of decision support systems. The identified critical success factors are grouped into the following categories: organizational, project, technical, information quality, system quality, service quality and net benefits.