2,023 research outputs found
Towards a lean model for production management of refurbishment projects, VTT Technology: 94
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.
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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
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
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
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
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
A lean way of design and production for healthcare construction projects
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
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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