697 research outputs found

    BPMNt : a proposal for flexible process tailoring representation in BPMN /

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    Business Process Model and Notation (BPMN) is a de-facto standard for business process modeling, which focuses on the representation of the process behavior. However, it can also succeed in representing the behavior of software processes, since they are a type of business process. Although BPMN has been extensively used for modeling processes in different domains, its standard specification does not have any mechanism to support users in activities related to process adaptation (tailoring). Moreover, researches extending BPMN are based on complex consolidated models, which hamper the analysis and maintenance of individual variant process models and are not appropriate for application domains in which process variations are difficult to predict, such as in software development processes. Thus, our objective was to provide a BPMN-compliant extension and associated mechanisms for specifying flexible process tailoring on models produced with this language while ensuring the correctness of adapted process models and explicitly capturing change traces. We have focused our research on the domains of Software Process Engineering (SPE) and Business Process Management (BPM). At last, we evaluated the applicability of the proposal for representing realistic tailoring scenarios in both domains.BPMN (Business Process Model and Notation) é um padrão para modelagem de processos de negócio, que tem seu foco na representação do comportamento de processos. No entanto, ele pode também ser usado para representar o comportamento de processos de software, já que eles são um tipo de processo de negócio. Embora BPMN tem sido extensivamente usado para modelar processos em diferentes domínios, sua especificação padrão não possui nenhum mecanismo para apoiar usuários em atividades relacionadas à adaptação de processos. Pesquisas que estendem o padrão são baseadas em modelos complexos, que dificultam a análise e manutenção de modelos variantes, e não são apropriadas para domínios de aplicação onde variações de processo são difíceis de predizer, como em processos de desenvolvimento de software. Assim, nosso objetivo foi fornecer uma extensão para BPMN, chamada BPMNt, e mecanismos de suporte para especificar, de modo flexível, adaptações em processos modelados com esta linguagem. BPMNt deve também garantir a corretude de modelos adaptados e explicitamente capturar rastros de mudanças realizadas. Essa pesquisa teve como foco os domínios de Engenharia de Processos de Software e Gerenciamento de Processos de Negócio. Por fim, nós avaliamos a aplicabilidade da proposta para representar cenários de adaptação reais em ambos os domínios

    Making the most of data:An information selection and assessment framework to improve water systems operations

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    Advances in Environmental monitoring systems are making a wide range of data available at increasingly higher temporal and spatial resolution. This creates an opportunity to enhance real-time understanding of water systems conditions and to improve prediction of their future evolution, ultimately increasing our ability to make better decisions. Yet, many water systems are still operated using very simple information systems, typically based on simple statistical analysis and the operator’s experience. In this work, we propose a framework to automatically select the most valuable information to inform water systems operations supported by quantitative metrics to operationally and economically assess the value of this information. The Hoa Binh reservoir in Vietnam is used to demonstrate the proposed framework in a multiobjective context, accounting for hydropower production and flood control. First, we quantify the expected value of perfect information, meaning the potential space for improvement under the assumption of exact knowledge of the future system conditions. Second, we automatically select the most valuable information that could be actually used to improve the Hoa Binh operations. Finally, we assess the economic value of sample information on the basis of the resulting policy performance. Results show that our framework successfully select information to enhance the performance of the operating policies with respect to both the competing objectives, attaining a 40% improvement close to the target trade-off selected as potentially good compromise between hydropower production and flood control

    Reliability-based Topology Optimization of Trusses with Stochastic Stiffness

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    A new method is proposed for reliability-based topology optimization of truss structures with random geometric imperfections and material variability. Such imperfections and variability, which may result from manufacturing processes, are assumed to be small in relation to the truss dimensions and mean material properties and normally distributed. Extensive numerical evidence suggests that the trusses, when optimized in terms of a displacement-based demand metric, are characterized by randomness in the stiffness that follow the Gumbel distribution. Based on this observation, it was possible to derive analytical expressions for the structural reliability, enabling the formulation of a computationally efficient single-loop reliability-based topology optimization algorithm. Response statistics are estimated using a second-order perturbation expansion of the stiffness matrix and design sensitivities are derived so that they can be directly used by gradient-based optimizers. Several examples illustrate the accuracy of the perturbation expressions and the applicability of the method for developing optimal designs that meet target reliabilities

    An Integrated CVaR and Real Options Approach to Investments in the Energy Sector

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    The objective of this paper is to combine a real options framework with portfolio optimization techniques and to apply this new framework to investments in the electricity sector. In particular, a real options model is used to assess the adoption decision of particular technologies under uncertainty. These technologies are coal-fired power plants, biomass-fired power plants and onshore wind mills, and they are representative of technologies based on fossil fuels, biomass and renewables, respectively. The return distributions resulting from this analysis are then used as an input to a portfolio optimization, where the measure of risk is the Conditional Value-at-Risk (CVaR)

    Implementation and evaluation of enhanced areal interpolation using MapInfo and MapBasic

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    Many researchers today have a need to analyse data in a spatial context. An inherent problem is the mismatch of boundaries between the geographic regions for which data is collected and those regions for which the data is required. Often the solution is to interpolate data from one set of regions to another. This project examines and implements a method of areal interpolation that enables the user to use extra information in areal interpolation to increase the intelligence \u27 of the process. This method of Enhanced Areal Interpolation uses a conditional Poisson distribution and the EM algorithm to provide estimated values of a variable. Enhanced Areal Interpolation assumes that data is available for a set of source regions, and is required for a set of target regions. Extra information available about the target regions provides an improved fit of the estimates compared to Areal Weighting Interpolation which uses area proportionality to distribute the data. The theory and concepts are illustrated with an example and implemented using the software packages Maplnfo version 3 for Windows and MapBasic version 3 for Windows
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