217,024 research outputs found
MODELLING TO RESOLVE DESIGN LINKED DELAY IN CONSTRUCTION PROJECTS
Published Conference ProceedingsConsultants are the major role players in design of construction projects. It is well
acknowledged that the consultant and design linked issues are more or less integrated
and influence delay in a project. Therefore, the objectives of the investigation are to
identify the influential consultant and design related variables, which cause delay; to
evolve the causal feedback relations among the most influential consultant and design
linked variables and delay; and to develop a model to estimate the reduction of delay
under varied strategic interventions. For this purpose a survey was conducted among
120 stakeholders and professionals from various construction projects in India. By
using System Dynamics (SD) modelling principles, causal feedback relations among
the most influential parameters that influence delay were established and dynamic
hypotheses were evolved for developing policy interventions to reduce delay. A SD
model was developed by using data from medium sized building projects in India to
examine the behaviour of the project schedule and delay under different simulated
scenarios, and estimate the reduction of delay under different policy interventions
based on the dynamic hypotheses framed. Findings suggest that there exist definite
causal feedback relations among the consultant and design linked variables, such as late
reviewing and approving of design documents by consultant, delay in approving major
changes in the scope of work by consultant, delay in performing inspection and testing
by consultant, poor communication/coordination between consultant and other parties,
inflexibility (rigidity) of the consultant, delays in producing design documents,
complexity of project design, mistakes and discrepancies in design documents, and
unclear and inadequate details in drawings, which essentially cause delay. However,
the model results revealed that policy interventions based on (1) causal feedback
mechanisms involving appointment of highly competent consultant and design team,
delay in producing the design documents and delay in construction; and (2) provision
of effective communication mechanism, conflict resolution and delay in construction
can reduce delay significantly
Knowledge Construction Technology through Hypermedia-Based Intelligent Conversational Channel
There have been multifarious approaches in building expert knowledge in medical or engineering field
through expert system, case-based reasoning, model-based reasoning and also a large-scale knowledge-based
system. The intriguing factors with these approaches are mainly the choices of reasoning mechanism, ontology,
knowledge representation, elicitation and modeling. In our study, we argue that the knowledge construction
through hypermedia-based community channel is an effective approach in constructing expert’s knowledge. We
define that the knowledge can be represented as in the simplest form such as stories to the most complex ones
such as on-the-job type of experiences. The current approaches of encoding experiences require expert’s
knowledge to be acquired and represented in rules, cases or causal model. We differentiate the two types of
knowledge which are the content knowledge and socially-derivable knowledge. The latter is described as
knowledge that is earned through social interaction. Intelligent Conversational Channel is the system that
supports the building and sharing on this type of knowledge
In defense of mechanism
In Life Itself and in Essays on Life Itself, Robert Rosen (1991, 2000) argued that machines were, in principle, incapable of modeling the defining feature of living systems, which he claimed to be the existence of closed causal loops. Rosen's argument has been used to support critiques of computational models in ecological psychology. This article shows that Rosen's attack on mechanism is fundamentally misconceived. It is, in fact, of the essence of a mechanical system that it contains closed causal loops. Moreover, Rosen's epistemology is based on a strong form of indirect realism and his arguments, if correct, would call into question some of the fundamental principles of ecological psychology
The Ongoing Impact of Modular Localization on Particle Theory
Modular localization is the concise conceptual formulation of causal
localization in the setting of local quantum physics. Unlike QM it does not
refer to individual operators but rather to ensembles of observables which
share the same localization region, as a result it explains the probabilistic
aspects of QFT in terms of the impure KMS nature arising from the local
restriction of the pure vacuum. Whereas it played no important role in the
perturbation theory of low spin particles, it becomes indispensible for
interactions which involve higher spin fields, where is leads to the
replacement of the operator (BRST) gauge theory setting in Krein space by a new
formulation in terms of stringlocal fields in Hilbert space. The main purpose
of this paper is to present new results which lead to a rethinking of important
issues of the Standard Model concerning massive gauge theories and the Higgs
mechanism. We place these new findings into the broader context of ongoing
conceptual changes within QFT which already led to new nonperturbative
constructions of models of integrable QFTs. It is also pointed out that modular
localization does not support ideas coming from string theory, as extra
dimensions and Kaluza-Klein dimensional reductions outside quasiclassical
approximations. Apart from hologarphic projections on null-surfaces, holograhic
relations between QFT in different spacetime dimensions violate the causal
completeness property, this includes in particular the Maldacena conjecture.
Last not least, modular localization sheds light onto unsolved problems from
QFT's distant past since it reveals that the Einstein-Jordan conundrum is
really an early harbinger of the Unruh effect.Comment: a small text overlap with unpublished arXiv:1201.632
Project pathogens: The anatomy of omission errors in construction and resource engineering project
Construction and engineering projects are typically
complex in nature and are prone to cost and schedule overruns.
A significant factor that often contributes to these overruns is rework.
Omissions errors, in particular, have been found to account
for as much as 38% of the total rework costs experienced. To date,
there has been limited research that has sought to determine the
underlying factors that contribute to omission errors in construction
and engineering projects. Using data derived from59 in-depth
interviews undertaken with various project participants, a generic
systemic causal model of the key factors that contributed to omission
errors is presented. The developed causal model can improve
understanding of the archetypal nature and underlying dynamics
of omission errors. Error management strategies that can be
considered for implementation in projects are also discussed
Modelling the Developing Mind: From Structure to Change
This paper presents a theory of cognitive change. The theory assumes that the fundamental causes of cognitive change reside in the architecture of mind. Thus, the architecture of mind as specified by the theory is described first. It is assumed that the mind is a three-level universe involving (1) a processing system that constrains processing potentials, (2) a set of specialized capacity systems that guide understanding of different reality and knowledge domains, and (3) a hypecognitive system that monitors and controls the functioning of all other systems. The paper then specifies the types of change that may occur in cognitive development (changes within the levels of mind, changes in the relations between structures across levels, changes in the efficiency of a structure) and a series of general (e.g., metarepresentation) and more specific mechanisms (e.g., bridging, interweaving, and fusion) that bring the changes about. It is argued that different types of change require different mechanisms. Finally, a general model of the nature of cognitive development is offered. The relations between the theory proposed in the paper and other theories and research in cognitive development and cognitive neuroscience is discussed throughout the paper
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