Computer Science Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/2756

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Subject: search.filters.subject.Engineering, System Science

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Now showing 1 - 10 of 11
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    An XML Application-Based Interface to Developing Modular System Simulations
    (2008-01-25) Weisflog, Jens; Adomaitis, Ray; Systems Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    We introduce a framework for the development of modular lumped and distributed parameter system models, the latter described by boundary value problems. The simulation of such systems requires careful analysis and a rigorous approach to development to provide both accuracy and computational efficiency. We explain the current implementation, which solves such systems in a MATLAB environment using object-oriented programming principles as part of the Modular Distributed Parameter System Analysis and Simulation (MDPSAS) package. We propose a mechanism for creating user-defined simulation elements using a web-based collaborative interface. The creation of a novel semantic vocabulary built into an XML application language called ModSimML is presented as a tool for data structuring and exchange. The development of a schema for the XML application formalizes of our data model. The utility of this interface is described via an application to research in Biological Micro-Electro-Mechanical Systems (BioMEMS), whose simulations require assembly from modular components.
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    ARCOLOGY OPTIMIZATION AND SIMULATION FRAMEWORK
    (2007-11-06) Andruscavage, Rowin Warin; Austin, Mark; Systems Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Arcology design combines urban planning and architecture with the mechanics of ecology. The physical design of an arcology would encompass the creation of a "hyperstructure" that delivers utility and transportation infrastructure in a highly integrated compact package. This thesis defines and describes a prototype simulation framework that would execute and evaluate intelligent demand-responsive multimodal mass transit schemes. Given a set of connected nodes serviced by different fleets of vehicles, a global optimizer attempts to generate a coordinated fleet schedule that meets various demand patterns. Factorial design of experiments and parametric analysis on the resulting simulated performance data of several simplified 1D and 2D scenarios help identify significant system design variables, including the number and size of the vehicle fleet, station configuration, transit network topology, and initial distribution of travel demand between station nodes. This tool explores the effectiveness of transit-oriented design paradigms supporting arcologies and other urban forms.
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    Designing a Decision-Making System for Providing Mutual Aid During Disasters
    (2007-05-07) Shaikh, Sana Tabrez; Herrmann, Jeffrey W.; Systems Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Routine organizational decision-making is a complex process, but organizations have procedures in place to support decision-making for routine situations. However, when an organization faces a crisis, the standard processes in place may not be enough to react appropriately to the crisis. Sometimes, due to the scale of the crisis and the resources needed, organizations may need to collaborate with other organizations to ensure success. This thesis addresses the design of such a mutual aid system as a type of a decision-making system. Our approach is based on the Operational Procedure Model used in avionics for specifying the dynamic behavior of operationally embedded reactive software-based systems. Using this approach, we designed and tested a mutual aid system to be used by five hospitals in Montgomery County, Maryland. Based on this experience, we propose a revised methodology for designing crisis decision-making systems.
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    System Modeling and Traceability Applications of the Higraph Formalism
    (2006-05-04) Fogarty, Kevin; Austin, Mark; Systems Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    One of the most important tools for a systems engineer is their system model. From this model, engineering decisions can be made without costly integration, fabrication, or installations. Existing system modeling languages used to create the system model are detailed and comprehensive, but lack a true ability to unify the system model by showing all relationships among all components in the model. Higraphs, a type of mathematical graph, allow systems engineers to not only represent all required information in a system model, but to formally show all relationships in the model through hierarchies, edges, and orthogonalities. With a higraph system model, all relationships between system requirements, components, and behaviors are formalized allowing for a "smart" model that can be queried for custom sets of information that, when presented to the systems engineer, will aid in engineering decisions.
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    Development of Requirements to Incorporate Neurophysiological Measures in Human Computer Interface Design
    (2005-12-08) Raley, Colby Dean; Austin, Mark; Systems Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This project specifies requirements for testing platforms and facilities that will enable the use of neurophysiological data to help improve human computer-interfaces. The data used to generate these requirements was collected as part of an advanced human factors effort aimed at improving the usability of future releases of the Tactical Tomahawk Weapons Control System (TTWCS). Cognitive state was measured using electrocardiography (EKG), galvanic skin response (GSR), and electroencephalography (EEG), in addition to traditional measures using various subjective and psychological analyses. This project demonstrated the value of neurophysiological measures into the Human Computer Interaction (HCI) design process, including increased objectivity of measures and consistency between measures. Simultaneous neurophysiological and psychological measurements will enable researchers to better understand true usability of an interface and the requirements documented herein will enable such research.
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    A SYSTEMS MODELING DESIGN UTILIZING AN OBJECT-ORIENTED APPROACH CONCERNING INFORMATION RISK MANAGEMENT
    (2005-10-11) Suzuki, Noriaki; Liu, Xicheng (Nelson); Systems Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Adopting advanced information technologies within the present broad application fields requires precise security. However, security problems regarding information privacy have occurred frequently over the last 5 years despite the contribution of these technologies. To respond to the need for securing information privacy, the Information Privacy Law was enacted on April 1, 2005 in Japan. One of the responses to this law enforcement is demanding a higher level of information risk management and search for more effective tools to be used for identity protection and problem-solving. Two examples of these tools include RAPID and IRMP. However, there is no established system-development model for either of these tools. Further developments to improve the RAPID and IRMP remain as new challenges. In this thesis, a new approach on developing a system security model to be used for information risk management is proposed. To demonstrate this approach, the object-oriented language is used.
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    Order Assignment and Resource Reservation: An Optimization Model and Policy Analysis
    (2005-05-31) McNeil, Julie Tricia; Ball, Michael O.; Systems Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    To maintain a competitive edge, companies today must be able to efficiently allocate resources to optimally commit and fulfill requested orders. As such, order processing and resource allocation models have become increasingly sophisticated to handle the complexity of these decisions. In our research, we introduce a model that integrates production scheduling, material allocation, delivery scheduling, as well as functions involving commitment of forecast demand for configure-to-order (CTO) and assemble-to-order (ATO) business environments. The model is formulated as a Mixed Integer Program (MIP) and seeks to maximize revenue by trading off commitment of higher profit forecast orders with the production and delivery schedule of lower profit accepted orders. Our model is particularly useful for testing different policies relating to order commitment, delivery mode selection and resource allocation.
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    An Extensible Order Promising and Revenue Management Test-bed
    (2005-05-27) Faber, Frederick Jon; Ball, Michael O; Systems Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Over the last quarter century it has become increasingly vital for large-scale businesses to exploit revenue management strategies. This is a consequence of thinning profit margins that have diminished from the effects of several pervasive trends. Among these trends are the globalization of markets, the regulation of particular industries, and, especially in the airline industry, the introduction of heightened security standards. To keep pace with this volatile landscape, revenue management and order promising policies rapidly have become more complex. Correspondingly, testing such policies has become increasingly difficult. This thesis presents an extensible test-bed designed to facilitate testing complex revenue management and order promising policies. The testbed was modeled and built using an agent-oriented architecture in order to reflect real-life business environments accurately. We describe the design and construction of the test-bed in this thesis. We then present case studies to highlight its capabilities.
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    Modeling, Validation and Verification of Concurrent Behavior in Canal System Using LTSA and UPPAAL
    (2005-05-01) Poorfarhani, Maliheh; Austin, Mark; Systems Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    A complex system is composed of subsystems. Common sense dictates complex systems in the physical world are reactive and concurrent in nature. The procedure to model a concurrent system and the procedure to validate its performance are complex because of the presence of the interactions between and among the subsystems, calling for an integrated approach from the viewpoint of systems engineering. In this thesis, a canal system is the object of study. The main objectives are to achieve a deadlock free and safe architectural model of a canal system, as measured by transportation criteria. Specifically, the Panama Canal is used as a case study where a procedure has been developed to model this waterway. This thesis models the scenario-based specifications, system behavioral model, animated verification and validation of the Panama Canal with LTSA and with the help of UPPAAL brings time constraints into the canal behavioral model.
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    Design of an Intelligent Sensor Network for Building Security
    (2004-08-10) Varangaonkar, Rajeshree Vijay; Baras, Dr. John S; Austin, Mark; Systems Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The thesis deals with the design of an intelligent sensor network for protecting premises from chemical, biological and intruder attacks. This thesis gives a logical level design along with the architectures at various levels of hierarchy. The use of object technology is proliferating in the development of software, and in order to build robust and maintainable complex systems, mastering object-oriented (O-O) analysis and design is essential. The main goal of this thesis is to report on the experience of applying object-oriented modeling, analysis and design methodology to a real-world complex system represented by an intelligent sensor network for a building. UML has been used to model the software and automation infrastructure, which handles the interactions among processing elements in a modern building. A set of system design requirements are developed that cover the hardware design of the nodes, the design of the sensor network, and the capabilities for remote data access and management. A formal model is proposed for the architecture, and the behavior diagrams explain the dynamic nature of the system. The static and dynamic diagrams together validate and verify the system. Agent UML is discussed to model evacuation of a room. This thesis discusses some extensions to UML for agent-based modeling where the agents follow a purely reactive and proactive approach. In this work, agent-based architectures and behavior diagrams are proposed as a method to envision security in buildings. Extensions are provided to support a multi room scenario. Sensor fusion is used to provide a robust functionality and reducing the events of false alarms occurring in the system. Linear programming techniques are used to solve for the minimal point in the cost vs. performance trade off curve for the sensor network as well as for the access system proposed. The tradeoff explores the relation of variables and suggests an operating point satisfying all constraints and without violating any requirement. Solver, an Excel add-in has been used to run the linear optimization.