1,997 research outputs found

    Towards a lean model for production management of refurbishment projects, VTT Technology: 94

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    This is the Stage 3 Report for the ApRemodel project, which aims at improving processes for multi-occupancy retrofit by generating a lean model for project delivery. In this respect, a process-driven approach has been adopted to investigate what can be done to improve the way that retrofits projects are delivered. An initial literature review, focused on the management of refurbishment works, revealed that the research on this matter is scarce. There are plenty of studies related to the broad refurbishment area, however only a small number refer to the way that those construction projects are delivered. According to the literature, construction organisations have predominantly used traditional methods for managing the production of refurbishment projects. The problem is that those tools and techniques are not often appropriate to cope with the complex characteristics inherent to construction projects, especially in the case of refurbishments. Moreover, they have often not been based on a clear theoretical foundation. As a result, numerous types of waste have been identified in refurbishment projects such as waiting time, disruptions in performing tasks on site, rework, among others. This has led to unsatisfactory project performance in terms of low productivity, project delays, and cost overrun. The first step towards better production management in refurbishment projects is recognising the complexity of the sector in order to adopt the correct approach to cope with this specific scenario. In this respect, lean construction is identified as an appropriate way to deal with the complexity and uncertainty inherent in refurbishment projects, given that this management philosophy fully integrates the conversion, flow, and value views. This document builds on the findings from the literature review as well as evidence from case studies. Managerial practices based on lean construction principles have presented successful results in the management of complex projects. Case studies available in the literature report the feasibility and usefulness of this theoretical foundation. Moreover, the evidence from these studies show considerable potential for improving the management of refurbishment works. A list of methods, tools, and techniques are identified. This report may be used by construction refurbishment organisations and housing associations as a starting point for improving the efficiency in managing production of refurbishment projects. To this end, partnerships between industry and academia are strongly recommended. 4 Although the usefulness of lean principles in complex projects is already proved, further work is needed to check what practices are best for the respective refurbishment context, as well as identifying enablers and barriers for practical adoption. Furthermore, additional studies would be also necessary to better understand the extent to which the implementation of lean philosophy might influence performance of refurbishment projects. This report should be seen as work in progress with much more to learn, as detailed research work around the sustainable retrofit process in a lean way is further developed

    Chiral freedom and electroweak symmetry breaking

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    Antisymmetric tensor fields with chiral couplings to quarks and leptons may induce spontaneous electroweak symmetry breaking in a model without a ``fundamental'' Higgs scalar. No microscopic local mass term for the chiral tensors or ``chirons'' is allowed by the symmetries and our model exhibits only dimensionless couplings. However, the chiral couplings are asymptotically free and therefore generate a mass scale where they grow large. We argue that at this scale mass terms for the chiral tensor fields are generated non-perturbatively - the chirons appear as new massive spin one particles. Furthermore a scalar top-antitop condensate forms, giving mass to the weak gauge bosons and fermions. In this scenario the longstanding gauge hierarchy problem finds a solution similar to the mass generation in QCD. We compute the general form of the effective action for the chiral tensors and sketch several possibilities of their detection at LHC or through precision tests of the electroweak standard model.Comment: 30 pages, 7 figure

    PIXEL 2010 - a Resume

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    The Pixel 2010 conference focused on semiconductor pixel detectors for particle tracking/vertexing as well as for imaging, in particular for synchrotron light sources and XFELs. The big LHC hybrid pixel detectors have impressively started showing their capabilities. X-ray imaging detectors, also using the hybrid pixel technology, have greatly advanced the experimental possibilities for diiffraction experiments. Monolithic or semi-monolithic devices like CMOS active pixels and DEPFET pixels have now reached a state such that complete vertex detectors for RHIC and superKEKB are being built with these technologies. Finally, new advances towards fully monolithic active pixel detectors, featuring full CMOS electronics merged with efficient signal charge collection, exploiting standard CMOS technologies, SOI and/or 3D integration, show the path for the future. This r\'esum\'e attempts to extract the main statements of the results and developments presented at this conference.Comment: 8 pages, 19 figures, conference summar

    A lean way of design and production for healthcare construction projects

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    As a consequence of the lack of solid conceptual foundation, the project management concepts and techniques usually applied within the construction sector are fragmented and have proved to be incapable of solving the complex problems of design management. As a result, healthcare providers have become frustrated with the outcomes such as cost and schedule overruns, accidents, less than expected quality and inadequate functionality. However, an investigation of successful healthcare projects reveals that new approaches have been developed to tackle such problems. This study uses recent data based on six construction projects. The idea is demonstrate how successful projects are dealing with the integration between design, production, and operations, through an appropriate approach to the management of production systems. The paper aims to assist the different parties of the AEC industry to better understand how practices applied into design phase could support the efficiency in the management of production systems

    Friedenssicherung durch Minderheitenschutz : Instrumente und Mechanismen der Vereinten Nationen

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    Ziel des vorliegenden Papers ist die Bewertung der Instrumente und Mechanismen der Vereinten Nationen zum Minderheitenschutz. Das friedliche Zusammenleben von Mehrheiten und Minderheiten innerhalb der Bevölkerung kann, so wird gezeigt, nur durch eine substanzielle Zusammenarbeit der internationalen Staatengemeinschaft erreicht werden. Auf Basis einer Analyse historischer Entwicklungen und mittels exemplarischer Untersuchungen dreier zentraler Minderheitenschutzinstrumente aus dem System der VN wird die Wirksamkeit der Menschenrechtsinstrumente bzw. Mechanismen auf theoretischer sowie legaler Ebene bewertet. Durch eine kritische Bewertung ihrer praktischen Umsetzung werden außerdem Alternativen zum existierenden internationalen Minderheitenschutzsystem aufgezeigt

    Marital fertility of Edinburgh professionals in the later nineteenth century

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    A lean way of design and production for healthcare construction projects

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    As a consequence of the lack of solid conceptual foundation, the project management concepts and techniques usually applied within the construction sector are fragmented and have proved to be incapable of solving the complex problems of design management. As a result, healthcare providers have become frustrated with the outcomes such as cost and schedule overruns, accidents, less than expected quality and inadequate functionality. However, an investigation of successful healthcare projects reveals that new approaches have been developed to tackle such problems. This study uses recent data based on six construction projects. The idea is demonstrate how successful projects are dealing with the integration between design, production, and operations, through an appropriate approach to the management of production systems. The paper aims to assist the different parties of the AEC industry to better understand how practices applied into design phase could support the efficiency in the management of production systems

    Suggestions to Improve Lean Construction Planning

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    The Last Planner System® has been one of the most popular lean construction tools that offers a solution to tackle the problems of production management on construction sites. Since its inception almost 20 years ago, construction companies across the world have implemented Last Planner with reported success. However, even as Last Planner was originally designed to address some shortcomings of the CPM method, a particular shortcoming – namely task continuity was not addressed directly. Also, excepting PPC and Reasons for Non Completion charts, there are no explicit visual tools offered by the Last Planner system. On the other hand, Line of Balance based approaches intrinsically support the consideration of task continuity, and offer a basic visual management approach in schedule representation. With some exceptions, Line of Balance is seen as a special technique applicable only in linear or repetitive work based schedules. The authors suggest that i) there is a need for a robust theory of planning and scheduling and ii) there is a need for a more suitable approach that addresses critical aspects of planning and scheduling function for example by integrating Line of Balance and Last Planner to provide a more robust support for construction scheduling
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