4,831 research outputs found

    A review of information flow diagrammatic models for product-service systems

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    A product-service system (PSS) is a combination of products and services to create value for both customers and manufacturers. Modelling a PSS based on function orientation offers a useful way to distinguish system inputs and outputs with regards to how data are consumed and information is used, i.e. information flow. This article presents a review of diagrammatic information flow tools, which are designed to describe a system through its functions. The origin, concept and applications of these tools are investigated, followed by an analysis of information flow modelling with regards to key PSS properties. A case study of selection laser melting technology implemented as PSS will then be used to show the application of information flow modelling for PSS design. A discussion based on the usefulness of the tools in modelling the key elements of PSS and possible future research directions are also presented

    Engineering failure analysis and design optimisation with HiP-HOPS

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    The scale and complexity of computer-based safety critical systems, like those used in the transport and manufacturing industries, pose significant challenges for failure analysis. Over the last decade, research has focused on automating this task. In one approach, predictive models of system failure are constructed from the topology of the system and local component failure models using a process of composition. An alternative approach employs model-checking of state automata to study the effects of failure and verify system safety properties. In this paper, we discuss these two approaches to failure analysis. We then focus on Hierarchically Performed Hazard Origin & Propagation Studies (HiP-HOPS) - one of the more advanced compositional approaches - and discuss its capabilities for automatic synthesis of fault trees, combinatorial Failure Modes and Effects Analyses, and reliability versus cost optimisation of systems via application of automatic model transformations. We summarise these contributions and demonstrate the application of HiP-HOPS on a simplified fuel oil system for a ship engine. In light of this example, we discuss strengths and limitations of the method in relation to other state-of-the-art techniques. In particular, because HiP-HOPS is deductive in nature, relating system failures back to their causes, it is less prone to combinatorial explosion and can more readily be iterated. For this reason, it enables exhaustive assessment of combinations of failures and design optimisation using computationally expensive meta-heuristics. (C) 2010 Elsevier Ltd. All rights reserved

    Towards efficient development of complete CAD frameworks

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    Acta Cybernetica : Volume 15. Number 4.

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    Interactive modelling and simulation of heterogeneous systems

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    An overview of decision table literature 1982-1995.

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    This report gives an overview of the literature on decision tables over the past 15 years. As much as possible, for each reference, an author supplied abstract, a number of keywords and a classification are provided. In some cases own comments are added. The purpose of these comments is to show where, how and why decision tables are used. The literature is classified according to application area, theoretical versus practical character, year of publication, country or origin (not necessarily country of publication) and the language of the document. After a description of the scope of the interview, classification results and the classification by topic are presented. The main body of the paper is the ordered list of publications with abstract, classification and comments.

    Specification of requirements models

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    The main aim of this chapter is to present and discuss a set of modeling and specification techniques, in what concerns their ontology and support in the requirements representation of computer-based systems. A systematic classification of meta-models, also called models of computation, is presented. This topic is highly relevant since it supports the definition of sound specification methodologies in relation to the semantic definition of the modeling views to adopt for a given system. The usage and applicability of Unified Modeling Language (UML) diagrams is also related to their corresponding meta-models. A set of desirable characteristics for the specification methodologies is presented and justified to allow system designers and requirements engineers to more consciously define or choose a particular specification methodology. A heuristic-based approach to support the transformation of user into system requirements is suggested, with some graphical examples in UML notation.(undefined

    Applied novel software development methodology for process engineering application

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    Chemical processes are nonlinear continuous/discrete dynamic systems that are subject to considerable uncertainties and variations during their design and operation. These systems are designed to operate at an economically optimal steady-state. However, minor changes in process parameters’ values might cause deviations and elicit dynamic responses from processes. Controllability—defined as the ability of holding a process within a specified operating regime and the controllability assessment of each given process system—should be taken into account during the system design phase. This emphasises the necessity of effective software tools that could assist process engineers in their controllability evaluation. Although there are few multipurpose tools available for this task, developing software tools for controllability analysis is a tedious and sophisticated undertaking. It involves elaboration from multiple disciplines, and the requirements of controllability assessments are so vast that it is almost impossible to create general software that covers all controllability measures and cases. This thesis aims to systematically tackle the challenge of developing practical and high-quality software tools for controllability problems while reducing the required time and effort, regardless of the size and scale of the controllability problem. Domain-specific language (DSL) methodology is proposed for this purpose. DSLs are programming languages designed to address the programming problems of a specific domain. Therefore, well-designed DSLs are simple, easy to use and capable of solving any problem defined in their domains. Based on DSL methodology, this study proposes a four-element framework to partition the software system into decoupled elements, and discusses the design and implementation steps of each element as well as communication between elements. The superiority of the developed methodology based on DSL is compared with traditional programming techniques for controllability assessment of various case studies. Essentially, the major advantage of the proposed methodology is the performance of the software product. Performance measures used in this study are total time to develop (TD) the software tool and its modifiability. Total time and effort to implement and use the result products presents up to five times improvement. Moreover, the result product’s modifiability is assessed by applying modifications, which also demonstrates up to five times improvement. All measures are tested on continuous stirred-tank reaction (CSTR) and forced-circulation evaporator (FCE) case studies. In conclusion, this study significantly contributes to two fields. The first is DSL, since this thesis studies different types of DSLs and evaluates their applications in the controllability analysis. The second is the controllability evaluation, since this study examines a new methodology for software development in controllability assessment
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