3,545 research outputs found

    Soldier system assessment under uncertainty with evidential reasoning

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    Along with the increasing of new equipment based capabilities, the physiological burden on the dismounted soldier keeps on growing, which leads to the limitation in the quantity and types of missions that can be carried out. In this research, a methodology is developed to solve the burden problem from the system assessment point of view. Comparing with other relevant research, the new methodology not only provides quantitative performance estimate of the soldier with the capability of handling fragmentary and incomplete data with hybrid format in nature (qualitative and quantitative), but also restrains the assessment complexity to an acceptable level

    Managing Vulnerabilities of Tactical Wireless RF Network Systems: A Case Study

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    Organisations and individuals benefit when wireless networks are protected. After assessing the risks associated with wireless technologies, organisations can reduce the risks by applying countermeasures to address specific threats and vulnerabilities. These countermeasures include management, operational and technical controls. While these countermeasures will not prevent all penetrations and adverse events, they can be effective in reducing many of the common risks associated with wireless RF networks. Among engineers dealing with different scaled and interconnected engineering systems, such as tactical wireless RF communication systems, there is a growing need for a means of analysing complex adaptive systems. We propose a methodology based on the systematic resolution of complex issues to manage the vulnerabilities of tactical wireless RF systems. There are is a need to assemble and balance the results of any successful measure, showing how well each solution meets the system’s objectives. The uncertain arguments used and other test results are combined using a form of mathematical theory for their analysis. Systems engineering thinking supports design decisions and enables decision‐makers to manage and assess the support for each solution. In these circumstances, complexity management arises from the many interacting and conflicting requirements of an increasing range of possible parameters. There may not be a single ‘right’ solution, only a satisfactory set of resolutions which this system helps to facilitate. Smart and innovative performance matrixes are introduced using a mathematical Bayesian network to manage, model, calculate and analyse all the potential vulnerability paths in wireless RF networks

    Understanding and Evaluating Assurance Cases

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    Assurance cases are a method for providing assurance for a system by giving an argument to justify a claim about the system, based on evidence about its design, development, and tested behavior. In comparison with assurance based on guidelines or standards (which essentially specify only the evidence to be produced), the chief novelty in assurance cases is provision of an explicit argument. In principle, this can allow assurance cases to be more finely tuned to the specific circumstances of the system, and more agile than guidelines in adapting to new techniques and applications. The first part of this report (Sections 1-4) provides an introduction to assurance cases. Although this material should be accessible to all those with an interest in these topics, the examples focus on software for airborne systems, traditionally assured using the DO-178C guidelines and its predecessors. A brief survey of some existing assurance cases is provided in Section 5. The second part (Section 6) considers the criteria, methods, and tools that may be used to evaluate whether an assurance case provides sufficient confidence that a particular system or service is fit for its intended use. An assurance case cannot provide unequivocal "proof" for its claim, so much of the discussion focuses on the interpretation of such less-than-definitive arguments, and on methods to counteract confirmation bias and other fallibilities in human reasoning

    Reacting to Risk with Real Options: Valuation of Managerial Flexibility in IT Projects.

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    Since flexibility is a critical success factor in relation to the management and design of IT investments, and understanding flexibility is a difficult issue, it is important to explore how firms build flexibility into their IT investment decisions. This dissertation investigates how managerial flexibility, as a response to risks, impacts IT project valuation. The dissertation attempts to answer this question by conducting three separate studies using a real options perspective. Firstly, we explore whether managerial flexibility in IT investment decisions is recognized in practice by conducting exploratory case study research. Secondly, we investigate how managerial flexibility in IT projects can be valued. We develop a theoretical decision-making model which deals with both financial and non-financial IT project valuation criteria and apply the model in a case study. Thirdly, we take a qualitative perspective on the management of managerial flexibility in relation to IT project risk. We empirically test the effects of specific risks on the valuation of real options in IT project decisions in an experimental setting. The primary contribution of this dissertation is to provide evidence that managers differentially assess the relative value of different types of options when controlling IT project risks. The relative value that IT professionals place on various real options is both driven by both the intrinsic real options value and by risk factors associated with an IT project. Their assessment generally follows real options-based risk management reasoning.

    Recommendation Framework Based on Subjective Logic in Decision Support Systems

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    In this thesis our goals are to investigate the suitability of subjective logic within the decision support context that requires connectivity to complex data, user specification of frames of discernment, representation of complex reasoning expressions, an architecture that supports distributed usage of a decision support tool based on a client-server approach that separates user interactions on the browser side from computational engines for calculations on the server side, and analysis of the suitability and limitations of the proposed architecture

    An Enhanced Approach to the Spatial and Statistical Analysis of Factors Influencing Spring Distribution on a Transboundary Karst Aquifer

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    Karst aquifers are indispensable, yet vulnerable, resources; therefore, they require a comprehensive protection strategy. Since springs are the terminal points of the karst flow systems, knowledge of their distribution is a key element for the better understanding of groundwater flow, availability and vulnerability. The present study aims to introduce a data-driven analysis by the application of a spatial statistical technique (Weights of Evidence (WofE)) for the evaluation of factors influencing spring distribution in karst areas. A workflow was developed for investigating two questions: where will the springs locate, and where will the permanent springs evolve? This workflow has the potential for application to unconfined karst areas. This enhanced approach was applied to an unconfined transboundary aquifer, the G\uf6m\uf6r\u2013Torna Karst (HU and SK). The roles of five factors was statistically investigated: terrain elevation, distance to faults, distance of the carbonate\u2013non-carbonate rock contact, distance to sinkholes, and precipitation distribution. The validation procedures confirmed the effectiveness of the approach. The resulting predictive maps are useful for decision-makers to delineate areas holding potential karst springs and to address water availability problems and protection measures. In addition, the WofE technique improved the comprehension of the geological conditions favourable for the formation of the springs

    Assessing system architectures: the Canonical Decomposition Fuzzy Comparative methodology

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    The impacts of decisions made during the selection of the system architecture propagate throughout the entire system lifecycle. The challenge for system architects is to perform a realistic assessment of an inherently ambiguous system concept. Subject matter expert interpretations, intuition, and heuristics are performed quickly and guide system development in the right overall direction, but these methods are subjective and unrepeatable. Traditional analytical assessments dismiss complexity in a system by assuming severability between system components and are intolerant of ambiguity. To be defensible, a suitable methodology must be repeatable, analytically rigorous, and yet tolerant of ambiguity. The hypothesis for this research is that an architecture assessment methodology capable of achieving these objectives is possible by drawing on the strengths of existing approaches while addressing their collective weaknesses. The proposed methodology is the Canonical Decomposition Fuzzy Comparative approach. The theoretical foundations of this methodology are developed and tested through the assessment of three physical architectures for a peer-to-peer wireless network. An extensible modeling framework is established to decompose high-level system attributes into technical performance measures suitable for analysis via computational modeling. Canonical design primitives are used to assess antenna performance in the form of a comparative analysis between the baseline free space gain patterns and the installed gain patterns. Finally, a fuzzy inference system is used to interpret the comparative feature set and offer a numerical assessment. The results of this experiment support the hypothesis that the proposed methodology is well suited for exposing integration sensitivity and assessing coupled performance in physical architecture concepts --Abstract, page iii
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