115 research outputs found

    Search-based system architecture development using a holistic modeling approach

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    This dissertation presents an innovative approach to system architecting where search algorithms are used to explore design trade space for good architecture alternatives. Such an approach is achieved by integrating certain model construction, alternative generation, simulation, and assessment processes into a coherent and automated framework. This framework is facilitated by a holistic modeling approach that combines the capabilities of Object Process Methodology (OPM), Colored Petri Net (CPN), and feature model. The resultant holistic model can not only capture the structural, behavioral, and dynamic aspects of a system, allowing simulation and strong analysis methods to be applied, it can also specify the architectural design space. Both object-oriented analysis and design (OOA/D) and domain engineering were exploited to capture design variables and their domains and define architecture generation operations. A fully realized framework (with genetic algorithms as the search algorithm) was developed. Both the proposed framework and its suggested implementation, including the proposed holistic modeling approach and architecture alternative generation operations, are generic. They are targeted at systems that can be specified using object-oriented or process-oriented paradigm. The broad applicability of the proposed approach is demonstrated on two examples. One is the configuration of reconfigurable manufacturing systems (RMSs) under multi-objective optimization and the other is the architecture design of a manned lunar landing system for the Apollo program. The test results show that the proposed approach can cover a huge number of architecture alternatives and support the assessment of several performance measures. A set of quality results was obtained after running the optimization algorithm following the proposed framework --Abstract, page iii

    A Software System Development Life Cycle Model for Improved Stakeholders’ Communication and Collaboration

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    Software vendors and entrepreneurs, who try to introduce an innovative software product to a specific organization or an entire market, enter a long and tedious process. During this process, the market and various organizations evaluate the product from different perspectives, such as software robustness, manufacturer reliability, and corporate need for the product. The vendors and entrepreneurs engaged in this process encounter decision crossroads for which no relevant guidance exists in the literature. The research closely monitored the processes associated with the introduction and assimilation of an innovative off-the-shelf (OTS) software product into five different organizations in different vertical market segments. Observations were carried out to assess organizational and marketing processes and to document and analyze what the software product undergoes before it is accepted for acquisition or full implementation within the organization. The research outcomes offer a unified, collaborative multi-tier System Development Life Cycle (SDLC) framework and methodology for packaged OTS software products that greatly improves communication and collaboration among the stakeholders. Each tier addresses a different force or stakeholder involved in the software market: vendor, customer, consultants and integrators. All stakeholders refer to the same time-line thus; tasks of various stakeholders are streamlined. Adherence to the unified time-line brings about an increased amount of stakeholder interaction, communication and collaboration. Newly found tasks that improve communication and collaboration among stakeholders include (1) offering of the OTS software product together with personnel as a bundle, (2) an improvisation-intensive iterative task of weaving potential customers’ requirements into the prototype, and (3) a third sale milestone, representing the successful diffusion of the product. The significance of this interdisciplinary research stems from its unique position at a crossroad between software engineering, marketing, and business administration, which has not yet been sufficiently explored or cultivated

    COIM: An Object-Process Based Method for Analyzing Architectures of Complex, Interconnected, Large-Scale Socio-Technical Systems

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    There is growing evidence for the relevance of human behavioral factors in successful development of new products, processes, and services. The evidence is even clearer when the forces affecting the development and evolution of long-lived, large, and open complex socio-technical systems are examined. Methods that study the architecture of these systems can help scholars and practitioners to better understand, manage, and develop socio-technical systems. We propose an approach and a method to address these needs that is grounded in the theory of systems architecture and builds on the strengths of Object Process Methodology (OPM) and the process for representing Complex Large-scale Interconnected Open Socio-technical (CLIOS) systems. We do so by integrating these methods into the CLIOS-OPM Integrated Method (COIM). COIM is conducive to studying a system's architecture and its evolution, as it is enhanced by a set of qualitative methods for answering questions about the reasons (why) and process (how) of change in human-made systems over time.Massachusetts Institute of Technology. Communications Futures ProgramNational Science Foundation (U.S.) (Grant #EIA-0306723

    Engenharia de sistemas baseada em modelos: um sistema para o tráfego & ambiente

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    Doutoramento em Gestão IndustrialThe contemporary world is crowded of large, interdisciplinary, complex systems made of other systems, personnel, hardware, software, information, processes, and facilities. The Systems Engineering (SE) field proposes an integrated holistic approach to tackle these socio-technical systems that is crucial to take proper account of their multifaceted nature and numerous interrelationships, providing the means to enable their successful realization. Model-Based Systems Engineering (MBSE) is an emerging paradigm in the SE field and can be described as the formalized application of modelling principles, methods, languages, and tools to the entire lifecycle of those systems, enhancing communications and knowledge capture, shared understanding, improved design precision and integrity, better development traceability, and reduced development risks. This thesis is devoted to the application of the novel MBSE paradigm to the Urban Traffic & Environment domain. The proposed system, the GUILTE (Guiding Urban Intelligent Traffic & Environment), deals with a present-day real challenging problem “at the agenda” of world leaders, national governors, local authorities, research agencies, academia, and general public. The main purposes of the system are to provide an integrated development framework for the municipalities, and to support the (short-time and real-time) operations of the urban traffic through Intelligent Transportation Systems, highlighting two fundamental aspects: the evaluation of the related environmental impacts (in particular, the air pollution and the noise), and the dissemination of information to the citizens, endorsing their involvement and participation. These objectives are related with the high-level complex challenge of developing sustainable urban transportation networks. The development process of the GUILTE system is supported by a new methodology, the LITHE (Agile Systems Modelling Engineering), which aims to lightening the complexity and burdensome of the existing methodologies by emphasizing agile principles such as continuous communication, feedback, stakeholders involvement, short iterations and rapid response. These principles are accomplished through a universal and intuitive SE process, the SIMILAR process model (which was redefined at the light of the modern international standards), a lean MBSE method, and a coherent System Model developed through the benchmark graphical modeling languages SysML and OPDs/OPL. The main contributions of the work are, in their essence, models and can be settled as: a revised process model for the SE field, an agile methodology for MBSE development environments, a graphical tool to support the proposed methodology, and a System Model for the GUILTE system. The comprehensive literature reviews provided for the main scientific field of this research (SE/MBSE) and for the application domain (Traffic & Environment) can also be seen as a relevant contribution.O mundo contemporâneo é caracterizado por sistemas de grande dimensão e de natureza marcadamente complexa, sócio-técnica e interdisciplinar. A Engenharia de Sistemas (ES) propõe uma abordagem holística e integrada para desenvolver tais sistemas, tendo em consideração a sua natureza multifacetada e as numerosas inter-relações que advêm de uma quantidade significativa de diferentes pontos de vista, competências, responsabilidades e interesses. A Engenharia de Sistemas Baseada em Modelos (ESBM) é um paradigma emergente na área da ES e pode ser descrito como a aplicação formal de princípios, métodos, linguagens e ferramentas de modelação ao ciclo de vida dos sistemas descritos. Espera-se que, na próxima década, a ESBM desempenhe um papel fundamental na prática da moderna Engenharia de Sistemas. Esta tese é dedicada à aplicação da ESBM a um desafio real que constitui uma preocupação do mundo actual, estando “na agenda” dos líderes mundiais, governantes nacionais, autoridades locais, agências de investigação, universidades e público em geral. O domínio de aplicação, o Tráfego & Ambiente, caracteriza-se por uma considerável complexidade e interdisciplinaridade, sendo representativo das áreas de interesse para a ES. Propõe-se um sistema (GUILTE) que visa dotar os municípios de um quadro de desenvolvimento integrado para adopção de Sistemas de Transporte Inteligentes e apoiar as suas operações de tráfego urbano, destacando dois aspectos fundamentais: a avaliação dos impactos ambientais associados (em especial, a poluição atmosférica e o ruído) e a divulgação de informação aos cidadãos, motivando o seu envolvimento e participação. Estes objectivos relacionam-se com o desafio mais abrangente de desenvolver redes de transporte urbano sustentáveis. O processo de desenvolvimento do sistema apoia-se numa nova metodologia (LITHE), mais ágil, que enfatiza os princípios de comunicação contínua, feedback, participação e envolvimento dos stakeholders, iterações curtas e resposta rápida. Estes princípios são concretizados através de um processo de ES universal e intuitivo (redefinido à luz dos padrões internacionais), de um método simples e de linguagens gráficas de modelação de referência (SysML e OPDs/OPL). As principais contribuições deste trabalho são, na sua essência, modelos: um modelo revisto para o processo da ES, uma metodologia ágil para ambientes de desenvolvimento baseados em modelos, uma ferramenta gráfica para suportar a metodologia proposta e o modelo de um sistema para as operações de tráfego & ambiente num contexto urbano. Contribui-se ainda com uma cuidada revisão bibliográfica para a principal área de investigação (ES/ESBM) e para o domínio de aplicação (Tráfego & Ambiente)

    Human Rights Treaty Commitment and Compliance: A Machine Learning-based Causal Inference Approach

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    Why do states ratify international human rights treaties? How much do human rights treaties influence state behaviors directly and indirectly? Why are some human rights treaty monitoring procedures more effective than others? What are the most predictively and causally important factors that can reduce and prevent state repression and human rights violations? This dissertation provide answers to these keys causal questions in political science research, using a novel approach that combines machine learning and the structural causal model framework. The four research questions are arranged in a chronological order that refects the causal process relating to international human rights treaties, going from (a) the causal determinants of treaty ratification to (b) the causal mechanisms of human rights treaties to (c) the causal effects of human rights treaty monitoring procedures to (d) other factors that causally influence human rights violations. Chapter 1 identifies the research traditions within which this dissertation is located, offers an overview of the methodological advances that enable this research, specifies the research questions, and previews the findings. Chapters 2, 3, 4, and 5 present in chronological order four empirical studies that answer these four research questions. Finally, Chapter 6 summarizes the substantive findings, suggests some other research questions that could be similarly investigated, and recaps the methodological approach and the contributions of the dissertation

    System level risk analysis of electromagnetic environmental effects and lightning effects in aircraft -- steady state and transient

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    2017 Summer.Includes bibliographical references.This dissertation is an investigation of the system level risk of electromagnetic and lightning effects in aircraft. It begins with an analysis to define a system, and a discussion of emergence as a characteristic of a system. Against this backdrop, risk is defined as an undesirable emergent property of a system. A procedure to translate the system level non-functional attributes to lower level functional requirements is developed. With this foundation, a model for risk analysis, resolution and management is developed by employing the standard risk model. The developed risk model is applied to evaluation of electromagnetic environmental effects and lightning effects in aircraft. Examples are shown to demonstrate the validity of the model. Object Process Methodology and systems thinking principles are used extensively throughout this work. The dissertation concludes with a summary and suggestions for additional work

    Enterprise modeling using the foundation concepts of the RM-ODP ISO/ITU standard

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    Enterprise architecture (EA) projects require analyzing and designing across the whole enterprise and its environment. Enterprise architects, therefore, frequently develop enterprise models that span from the markets in which the organization operates down to the implementation of the IT systems that support its operations. In this paper, we present SEAM for EA: a method for defining an enterprise model in which all the systems are systematically represented with the same modeling ontology. We base our modeling ontology on the foundation modeling concepts defined in Part 2 of ISO/ITU Standard "Reference Model of Open Distributed Processing” (RM-ODP). This work has two contributions to enterprise architecture: the SEAM for EA method itself and the use of Part 2 of the RM-ODP standard as a modeling ontolog

    Intelligence Oversight In Times of Transnational Impunity: Who Will Watch the Watchers?

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    This book adopts a critical lens to look at the workings of Western intelligence and intelligence oversight over time and space. Largely confined to the sub-field of intelligence studies, scholarly engagements with intelligence oversight have typically downplayed the violence carried out by secretive agencies. These studies have often served to justify weak oversight structures and promoted only marginal adaptations of policy frameworks in the wake of intelligence scandals. The essays gathered in this volume challenge the prevailing doxa in the academic field, adopting a critical lens to look at the workings of intelligence oversight in Europe and North America. Through chapters spanning across multiple disciplines–political sociology, history, and law–the book aims to recast intelligence oversight as acting in symbiosis with the legitimisation of the state’s secret violence and the enactment of impunity, showing how intelligence actors practically navigate the legal and political constraints created by oversight frameworks and practices, for instance by developing transnational networks of interdependence. The book also explores inventive legal steps and human rights mechanisms aimed at bridging some of the most serious gaps in existing frameworks, drawing inspiration from recent policy developments in the international struggle against torture. This book will be of much interest to students of intelligence studies, sociology, security studies, and international relations

    A systems approach to mitigation of project failure modes

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    Thesis (S.M.)--Massachusetts Institute of Technology, System Design and Management Program, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 177).This thesis sets out to develop a systems approach towards the mitigation of project failure modes. The methodology used is the application of the Scope and Solution Neutrality principle to develop a general model for Project Systems using the Object- Process-Method (OPM) for systems modeling. By correlating the elements and attributes that constitute basic project artifacts with process performance enablers, a Systems Approach to Performance Improvements is developed. Systemic factors that affect a project's performance, and its ability to address issues, are identified using the Project System model, and project failure modes as well with their underlying causes are examined. The Systems Approach to Process Improvements is then applied to addressing these issues. A key insight gained from the modeling is the importance of communication and information flow as a critical function for effective project management and execution. Consequently the impact of optimizing information flow on project execution is demonstrated through systems dynamics modeling.by Athar A. Syed.S.M
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