Universiẗat, Diss., 2001--Kassel. / Lizenzpflichtig.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3896. Adviser: Marco Caccamo. Includes bibliographical references (leaves 127-137) Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 4034. Adviser: Sheldon H. Jacobson. Includes bibliographical references (leaves 123-128) Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 163-171). Available also in a digital version from Dissertation Abstracts.

Thesis (M.S.)--University of Texas at Dallas, 2008. / Includes vita. Includes bibliographical references (leaves 57-60)

abstract: In the entire supply chain, demand planning is one of the crucial aspects of the production planning process. If the demand is not estimated accurately, then it causes revenue loss. Past research has shown forecasting can be used to help the demand planning process for production. However, accurate forecasting from historical data is difficult in today's complex volatile market. Also it is not the only factor that influences the demand planning. Factors, namely, Consumer's shifting interest and buying power also influence the future demand. Hence, this research study focuses on Just-In-Time (JIT) philosophy using a pull control strategy implemented with a Kanban control system to control the inventory flow. Two different product structures, serial product structure and assembly product structure, are considered for this research. Three different methods: the Toyota Production System model, a histogram model and a cost minimization model, have been used to find the number of kanbans that was used in a computer simulated Just-In-Time Kanban System. The simulation model was built to execute the designed scenarios for both the serial and assembly product structure. A test was performed to check the significance effects of various factors on system performance. Results of all three methods were collected and compared to indicate which method provides the most effective way to determine number of kanbans at various conditions. It was inferred that histogram model and cost minimization models are more accurate in calculating the required kanbans for various manufacturing conditions. Method-1 fails to adjust the kanbans when the backordered cost increases or when product structure changes. Among the product structures, serial product structures proved to be effective when Method-2 or Method-3 is used to calculate the kanban numbers for the system. The experimental result data also indicated that the lower container capacity collects more backorders in the system, which increases the inventory cost, than the high container capacity for both serial and assembly product structures. / Dissertation/Thesis / M.S. Industrial Engineering 2012

The thesis examines some of the methodologies used for conflict study and analysis; it reviews Operational Research based approaches and methodologies from other areas of study that have been, and are still being used for the study and analysis of conflict situations in complex systems. The thesis argues against the prevalent use of single methodologies for such systems, and calls for the adoption of approaches that allows the use of multiple methodologies, which would place the emphasis on the "problem" rather than on any particular approach or methodology. The nature, causes and effects, ecology of conflict, and the concept of issue relevance and irrelevance are examined as well as the role of perceptions. The factors determining thedevelopment, level and scope of conflicts are reviewed with the aim of ascertaining their importance to conflict outcomes andwhen meaningful intervention could be made during conflict situations. Various outcomes of conflict, primarily management, dissolution, and resolution are discussed and their relative strengths and weaknesses as strategies for handling conflicts. Case studies are used to examine and support arguments about how different conflict outcomes arise and some proposals are made for the study of alternative futures. It is argued that undesired conflicts could be reduced or prevented in complex interaction systems through the deliberate design and incorporation, into such systems, of structures and mechanisms that will serve as integration systems. These integration systems involve all the parties in an interaction system and are intended to reconcile views, clarify positions, inform the parties about each other and assist in the formulation of joint responses to negative internal and external stimuli. An outline structure of an integration system is given and how it could be developed in a system. Many methodologies and approaches are based on the premise of a "prima facie" existence of a conflict; a tool is suggested in the thesis that will assist analysts, observers, or any interested party to monitor the relationship in an interaction system. This tool concerns what I have called the Y-points and Y-diagrams. The Y-concepts are based on the notion that there are periods in an interaction when a decision can be consciously taken to escalate or de-escalate a situation. The approach advocated in the thesis is based on two assumptions: the first is that the parties prefer a "normal" relationship to a conflictual one, the second is that the parties in a conflict would prefer the resolution of a conflict and its attendant stability to an unending management of the situation. Consequently, the main thrust of the arguments in the thesis is on conflict resolution and the design of stability into complex interaction systems.

The process of operational research is traditionally described by a list of sub-processes, starting with a description, definition or formulation of the problem. Explicit methodology for this formulation is sparse. Earlier research on the nature of conflict and its resolution produced a diagrammatic notation, which seemed capable of extension and use as a problem-formulation 'language'. This thesis examines a wide range of methodology, directly or peripherally related to problem-formulation. It then argues the case for carrying out research to develop the diagrammatic notation as a medium for communication between an operational researcher and his clients, in order to establish in detail what their 'problem' is and perhaps to monitor the process of resolving it. The notation, and rules for its use, are developed and described in detail, and then used to help decide how the problem formulation process itself is to be managed. The difficulty of 'proving' a methodology is examined and the principles and purpose of experiment in this context is discussed. A suitable group of people with a shared problem was approached, and agreed to an experimental consultancy. The methodology was thereby tested 'successfully', in the sense defined in the thesis. The consultancy is in abeyance, but a start has been made with the use of the methodology in a study in support of a hospital accident and emergency department; it is also to be used in a study of decision-making in higher military commands. Further applied research will also be needed to find out how best it can be used to enhance the early stages of systems practice (Checkland), the analysis of options (Radford; Howard) and hypergame analysis (Bennett). Present evidence suggests that the procedures and practice described in this thesis are consistent with and complementary to these and other methodologies.

This thesis describes a research inquiry into models which could be used in an interactive manner for formulating problems and exploring manager's needs for decision aids. It reviews a wide range of literature in Operational Research Methodology, Models and Games, and then argues the case that what managers want are models which could allow them to reflect on the way they manage process and not those which simulate that process. A two phase practical study was carried out in association with two departments of a large organisation in which a group of managers were interested in the basic aims of the study and willing to cooperate. The aim was to research their managerial environment, seeking ways to improve management control of the processes which they do not directly involve themselves in, except by managing those who do. In phase one, Bowen's Problem Formulation Methodology was used to structure and feed back the data obtained from managers. The Methodology proved to be a very effective tool to help both the Operational Researcher and the Problem Owners to communicate and identify potential problem areas and failures in communications and purposeful actions. In phase two, a computer - based system was developed for the General Manager of one department to help him in the recording of and access to essential features of his current problems and communications about them. The system could be extended as a planning schedule and process control held in common by a management group, a decision support system for the department as a whole.

<p> Software vulnerabilities that enable well-known exploit techniques for committing computer crimes are <i>preventable</i>, but they continue to be present in releases. When Blackhats (i.e., malicious researchers) discover these vulnerabilities they oftentimes release corresponding exploit software and malware. If vulnerabilities&mdash;or discoveries of them&mdash;are not prevented, mitigated, or addressed, customer confidence could be reduced. In addressing the issue, software-makers must choose which mitigation alternatives will provide maximal impact and use vulnerability discovery modeling (VDM) techniques to support their decision-making process. In the literature, applications of these techniques have used traditional approaches to analysis and, despite the dearth of data, have not included information from experts and do not include influential variables describing the software release (SR) (e.g., code size and complexity characteristics) and security assessment profile (SAP) (e.g., security team size or skill). Consequently, they have been limited to modeling discoveries over time for SR and SAP scenarios of unique products, whose results are not readily comparable without making assumptions that equate all SR and SAP combinations under study. This research takes an alternative approach, applying Bayesian methods to modeling the vulnerability-discovery phenomenon. Relevant data were obtained from expert judgment (i.e., information elicited from security experts in structured workshops) and from public databases. The open-source framework, MCMCBayes, was developed to perform Bayesian model averaging (BMA). It combines predictions of interval-grouped discoveries by performance-weighting results from six variants of the non-homogeneous Poisson process, two regression models, and two growth-curve models. Utilizing expert judgment also enables forecasting expected discoveries over time for arbitrary SR and SAP combinations, thus helping software-makers to better understand the effects of influential variables they control on the phenomenon. This requires defining variables that describe arbitrary SR and SAP combinations as well as constructing VDM extensions that parametrically scale results from a defined baseline SR and SAP to the arbitrary SR and SAP of interest. Scaling parameters were estimated using elicited multivariate data gathered with a novel paired comparison approach. MCMCBayes uses the multivariate data with the BMA model for the baseline to perform predictions for desired SR and SAP combinations and to demonstrate how multivariate VDM techniques could be used. The research is applicable to software-makers and persons interested in applications of expert-judgment elicitation or those using Bayesian analysis techniques with phenomena having non-decreasing counts over time.</p><p>