12,486 research outputs found

    Preliminary design enhancement by incorporating set- based design principles and a navigator

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    The need for improvement of Product Development (PD) processes has been demonstrated by a high demand for the aerospace products to be developed quicker and cheaper. Set-Based Design (SBD) can improve the ability to respond faster to customers’ requirements by developing a set of design solutions for possible future product orders in parallel. In SBD participants practise SBCE (Set-Based Concurrent Engineering) by reasoning, developing and communicating about sets of solutions in parallel. As the design progresses, they gradually narrow their respective sets of solutions based on the knowledge gained. As they narrow, they commit to staying within the sets so that others can rely on their communication (Sobek et al, 1999). This research aims to develop logical guidelines for the selection of the PD tools and methods to enable the effective application of the SBD process model guided by a computerized tool, called ‘SBD Navigator’. An integration of the SBD good practices into the collaborator’s PD processes is believed to reduce the possibility of the negative design iteration and to reduce PD time thus providing financial benefits. Understanding the selection of PD methods and tools within manufacturing companies is a starting point of this research. It reveals main causes of poor incorporation of PD methods and tools in the preliminary design phase that might stop businesses from gaining a full range of benefits out of the SBD process model. As time goes on, PD becomes more difficult to manage due to the necessity of the collaboration among business participants in order to create complex and well integrated products. This research project has employed one of the deliverables from the CONGA (Concept Optimisation of Next Generation Aircraft) project which is the SBD process model customized by the collaborating company – Rolls-Royce plc. The RR-SBD process model is presented in chapter 3. [cont.

    Logic programming in the context of multiparadigm programming: the Oz experience

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    Oz is a multiparadigm language that supports logic programming as one of its major paradigms. A multiparadigm language is designed to support different programming paradigms (logic, functional, constraint, object-oriented, sequential, concurrent, etc.) with equal ease. This article has two goals: to give a tutorial of logic programming in Oz and to show how logic programming fits naturally into the wider context of multiparadigm programming. Our experience shows that there are two classes of problems, which we call algorithmic and search problems, for which logic programming can help formulate practical solutions. Algorithmic problems have known efficient algorithms. Search problems do not have known efficient algorithms but can be solved with search. The Oz support for logic programming targets these two problem classes specifically, using the concepts needed for each. This is in contrast to the Prolog approach, which targets both classes with one set of concepts, which results in less than optimal support for each class. To explain the essential difference between algorithmic and search programs, we define the Oz execution model. This model subsumes both concurrent logic programming (committed-choice-style) and search-based logic programming (Prolog-style). Instead of Horn clause syntax, Oz has a simple, fully compositional, higher-order syntax that accommodates the abilities of the language. We conclude with lessons learned from this work, a brief history of Oz, and many entry points into the Oz literature.Comment: 48 pages, to appear in the journal "Theory and Practice of Logic Programming

    What is a system? NASA's phased project description

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    NASA phase A and B projects are addressed. The Phase A study is the preliminary analysis of a space concept. These concepts could have come from a pre-Phase A study or from other sources within or external to NASA. The majority of concepts that are studied at MSFC are assigned by NASA Headquarters and funded accordingly. The overall program schedule depicts important milestones that establish the start and finish dates of each study phase, including design, development, launch, and operations. The Phase B of the project consists of the refinement of preliminary requirements, cost estimates, schedules and risk assessments prior to starting final design and development. The goal of a concept definition activity is to determine the best and most feasible concept(s) that will satisfy the mission and science requirements

    Concurrent optimization of process parameters and product design variables for near net shape manufacturing processes

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    This paper presents a new systematic approach to the optimization of both design and manufacturing variables across a multi-step production process. The approach assumes a generic manufacturing process in which an initial Near Net Shape (NNS) process is followed by a limited number of finishing operations. In this context the optimisation problem becomes a multi-variable problem in which the aim is to optimize by minimizing cost (or time) and improving technological performances (e.g. turning force). To enable such computation a methodology, named Conditional Design Optimization (CoDeO) is proposed which allows the modelling and simultaneous optimization of process parameters and product design (geometric variables), using single or multi-criteria optimization strategies. After investigation of CoDeO’s requirements, evolutionary algorithms, in particular Genetic Algorithms, are identified as the most suitable for overall NNS manufacturing chain optimization The CoDeO methodology is tested using an industrial case study that details a process chain composed of casting and machining processes. For the specific case study presented the optimized process resulted in cost savings of 22% (corresponding to equivalent machining time savings) and a 10% component weight reduction

    Enhancing the Competitiveness of the European Construction Industry in the Digital Economy

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    Funding bodies in general, and the European Commission in particular, have for over a decade funded project centred Research and Technology Development (RTD) efforts. While these have traditionally operated in isolation with little co-operation and cross-fertilization of results, a crucial requirement has emerged, following the latest advances in Information and Communication Technologies (ICT), to have a more concerted and co-ordinated action aiming at a better integration, standardisation, dissemination and exploitation of the results from these projects across the European regions and countries. This has been clearly identified as a key requirement within the European Information Society and Technology (IST) Programme. In that respect, based on the promising results and achievements realized by the leading Construction IT community in Europe, a cluster project involving six IST funded projects has been set-up in order to achieve a better integration of research results in the area. This project, ICCI (IST-2001-33022), is targeting a specific sector: the Construction industry, and is addressing a wide spectrum of issues ranging from ICT implementation and deployment to organizational, social, and legal aspects. The paper gives (1) a background description of the context in which ICCI operates, (2) its aims and objectives, (3) the research results achieved to date by its partners within their respective IST project, and (4) a road map identifying areas of collaboration and expected impacts in the European Construction digital economy

    Set-Based Prototyping in the Context of the Configurable Virtual Product: The Construction of the Learning Value Streams (LVS) Model

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    RÉSUMÉ La présente thèse de doctorat est le résultat de sept années de recherche intervention dans les domaines de la conception et du développement de produits suivant le paradigme lean en aérospatial. Cette recherche action est motivée par la nécessité de développer les connaissances ainsi que les outils appropriés pour le développement de produits suivant l’approche lean (LPD pour Lean Product Development) et en particulier celle de l’ « ingénierie concourante fondée sur les options de conception » (SBCE pour Set-Based Concurrent Engineering) en aérospatial. Une telle nécessité se justifie par les facteurs socioéconomiques du 21ème siècle qui imposent des approches de conception et développement toujours plus robustes, résilientes, réactives, flexibles, innovantes et adaptables face aux fluctuations du marché et à la demande des consommateurs qui évolue rapidement, ceci afin de permettre aux compagnies de demeurer compétitives. L’objectif principal de la recherche, au vue de tels impératifs, est d’identifier, pour ensuite développer et intégrer dans un modèle holistique, les aspects, les caractéristiques et les catalyseurs essentiels des approches LPD et SBCE appliquées à l’industrie aérospatiale de façon à supporter l’implémentation à grande échelle de telles approches, et ce, dans une optique sousjacente de gestion de cycle de vie du produit (PLM pour Product Lifecycle Management). La planification et l’exécution du projet de recherche sont réalisées en respectant une méthodologie éprouvée en conception (DRM pour Design Research Methodology) afin de focaliser les résultats sur l’avancement des connaissances et de la pratique du LPD et SBCE en tant qu’approches de conception. La recherche apporte en conséquence des contributions majeures à ces champs d’étude tout en prescrivant une méthodologie de transformation des processus et outils de développement de produits dans l’industrie par le biais de l’implémentation du modèle de « chaines de valeur apprenantes » (LVS pour Learning Value Streams). Plus en détails, les contributions aux avancées scientifiques et pratiques dans le domaine vont comme suit : (1) La proposition d’un nouveau cadre d’analyse de la littérature SBCE, ainsi qu’une méthodologie de revue systématique fondée sur des données probantes; (2) L’avancement des connaissances théoriques et pratiques du LPD et SBCE des aspects les plus généraux aux plus significatifs; (3) L’avancement des connaissances théoriques et pratiques sur la modélisation et les structures de produit requises dans une optique de gestion de cycle de vie du produit----------ABSTRACT The work reported in this thesis is the result of seven years of participatory action research in the field of Lean Product Development (LPD) in aerospace engineering. This research is motivated by the necessity to develop understanding and support for practical implementations of lean product development and especially Set-Based Concurrent Engineering (SBCE) in industry. Such necessity is justified by 21st century compelling socioeconomic factors that demand robust, resilient, responsive, flexible, innovative, adaptable and lean product development processes in order for companies to stay competitive in rapidly changing markets. The main purpose of the research is to identify and develop the essential SBCE and LPD aspects, characteristics, features and catalysts as they relate to aerospace large-scale industrial product development in order to form a holistic model that can support practical implementations of LPD in industry from a product lifecycle perspective. A design research methodology (DRM) is used for planning and executing the design research project while ensuring that focus is placed on achieving progress with regards to understanding and implementation of SBCE and LPD as Design practices. As a result, this thesis work provides substantial contribution to understanding of LPD and SBCE and furthermore, entails valuable proposal for the practice in industry through the CCS model and the construction of the Learning Value Streams (LVS) model. Major contributions to the advancement of scientific knowledge and practice in the fields are as follows: (1) The proposal of a new SBCE dual analysis framework combined with an evidence-based systematic review methodology; (2) The advancement of theoretical and practical understanding of LPD and SBCE from the larger to the most significant aspects; (3) The advancement of theoretical and practical understanding of product models and product structure progression requirements for lean product lifecycle management; (4) the proposal of a new methodology, including new as-tested structure to support cross-collaboration during prototyping and testing in lifecycle management contexts; (5) The proposal of a new existential domain alongside the functional, technological and physical domains in order to address the lack of product modelling constructs and methodology when it comes to service or as-tested configurations, hardware testing transactions and prototype information tracking on the basis o

    Towards narrowing the reality gap in electromechanical systems: error modeling in virtual commissioning

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    Digital factories and smart manufacturing systems have been increasingly researched and multiple concepts were developed to cope with prevailing ever-shortening life-cycles. The ubiquitous digital twin, despite many definitions, is often praised for accurate virtual models. One key idea to improve manufacturing through such virtual models is virtual commissioning\textit{virtual commissioning} (VC), aiming at early machine code validation. VC and its virtual models are still lacking behind their real counterparts. This gap between reality and its virtual model, commonly termed reality gap\textit{reality gap}, increases the complexity of creating cyber-physical systems. An especially stark contrast is visible between the idealized virtual model and a real machine encountering errors. While error simulations exist in other fields of research, a thorough investigation in VC is missing. Thus, this paper addresses the task of narrowing the reality gap in VC based on two steps. First, a comprehensive body of research of possible errors encountered in virtual commissioning is analyzed. Secondly, the feasibility of error implementation is discussed. This paper lays the foundation for narrowing the reality gap and enabling test automation and digital twin-based control

    From manufacturing to design : an essay on the work of Kim B. Clark. Harvard Business School Working Paper- 07-057

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    In this paper, we describe Clark's research and discuss his contributions to management scholarship and economics. We look at three distinct bodies of work. In the first, Clark (in conjunction with Robert Hayes and Steven Wheelwright) argued that the abandonment by U.S. managers of manufacturing as a strategic function exposed U.S. companies to Japanese competition in terms of the cost and quality of goods. In the second, conducted with Wheelwright, Bruce Chew, Takahiro Fujimoto, Kent Bowen and Marco Iansiti, Clark made the case that product development could be managed in new ways that would lead to significant competitive advantage for firms. Finally, in work conducted with Abernathy, Rebecca Henderson and Carliss Baldwin, Clark placed product and process designs at the center of his explanation of how innovation determines the structure and evolution of industries.
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