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Model-based groupware solution for distributed real-time collaborative 4D planning via teamwork
Construction planning plays a fundamental role in construction project management that requires team working among planners from a diverse range of disciplines and in geographically dispersed working situations. Model-based four-dimensional (4D) computer-aided design (CAD) groupware, though considered a possible approach to supporting collaborative planning, is still short of effective collaborative mechanisms for teamwork due to methodological, technological and social challenges. Targeting this problem, this paper proposes a model-based groupware solution to enable a group of multidisciplinary planners to perform real-time collaborative 4D planning across the Internet. In the light of the interactive definition method, and its computer-supported collaborative work (CSCW) design analysis, the paper discusses the realization of interactive collaborative mechanisms from software architecture, application mode, and data exchange protocol. These mechanisms have been integrated into a groupware solution, which was validated by a planning team in a truly geographically dispersed condition. Analysis of the validation results revealed that the proposed solution is feasible for real-time collaborative 4D planning to gain a robust construction plan through collaborative teamwork. The realization of this solution triggers further considerations about its enhancement for wider
groupware applications
VisIVO - Integrated Tools and Services for Large-Scale Astrophysical Visualization
VisIVO is an integrated suite of tools and services specifically designed for
the Virtual Observatory. This suite constitutes a software framework for
effective visual discovery in currently available (and next-generation) very
large-scale astrophysical datasets. VisIVO consists of VisiVO Desktop - a stand
alone application for interactive visualization on standard PCs, VisIVO Server
- a grid-enabled platform for high performance visualization and VisIVO Web - a
custom designed web portal supporting services based on the VisIVO Server
functionality. The main characteristic of VisIVO is support for
high-performance, multidimensional visualization of very large-scale
astrophysical datasets. Users can obtain meaningful visualizations rapidly
while preserving full and intuitive control of the relevant visualization
parameters. This paper focuses on newly developed integrated tools in VisIVO
Server allowing intuitive visual discovery with 3D views being created from
data tables. VisIVO Server can be installed easily on any web server with a
database repository. We discuss briefly aspects of our implementation of VisiVO
Server on a computational grid and also outline the functionality of the
services offered by VisIVO Web. Finally we conclude with a summary of our work
and pointers to future developments
GATE : a simulation toolkit for PET and SPECT
Monte Carlo simulation is an essential tool in emission tomography that can
assist in the design of new medical imaging devices, the optimization of
acquisition protocols, and the development or assessment of image
reconstruction algorithms and correction techniques. GATE, the Geant4
Application for Tomographic Emission, encapsulates the Geant4 libraries to
achieve a modular, versatile, scripted simulation toolkit adapted to the field
of nuclear medicine. In particular, GATE allows the description of
time-dependent phenomena such as source or detector movement, and source decay
kinetics. This feature makes it possible to simulate time curves under
realistic acquisition conditions and to test dynamic reconstruction algorithms.
A public release of GATE licensed under the GNU Lesser General Public License
can be downloaded at the address http://www-lphe.epfl.ch/GATE/
Conceptual Spaces in Object-Oriented Framework
The aim of this paper is to show that the middle level of
mental representations in a conceptual spaces framework is consistent
with the OOP paradigm. We argue that conceptual spaces framework
together with vague prototype theory of categorization appears to be
the most suitable solution for modeling the cognitive apparatus of
humans, and that the OOP paradigm can be easily and intuitively
reconciled with this framework. First, we show that the prototypebased
OOP approach is consistent with Gärdenfors’ model in terms
of structural coherence. Second, we argue that the product of cloning
process in a prototype-based model is in line with the structure of
categories in Gärdenfors’ proposal. Finally, in order to make the fuzzy
object-oriented model consistent with conceptual space, we
demonstrate how to define membership function in a more cognitive
manner, i.e. in terms of similarity to prototype
Autonomous Dynamics in Neural networks: The dHAN Concept and Associative Thought Processes
The neural activity of the human brain is dominated by self-sustained
activities. External sensory stimuli influence this autonomous activity but
they do not drive the brain directly. Most standard artificial neural network
models are however input driven and do not show spontaneous activities.
It constitutes a challenge to develop organizational principles for
controlled, self-sustained activity in artificial neural networks. Here we
propose and examine the dHAN concept for autonomous associative thought
processes in dense and homogeneous associative networks. An associative
thought-process is characterized, within this approach, by a time-series of
transient attractors. Each transient state corresponds to a stored information,
a memory. The subsequent transient states are characterized by large
associative overlaps, which are identical to acquired patterns. Memory states,
the acquired patterns, have such a dual functionality.
In this approach the self-sustained neural activity has a central functional
role. The network acquires a discrimination capability, as external stimuli
need to compete with the autonomous activity. Noise in the input is readily
filtered-out.
Hebbian learning of external patterns occurs coinstantaneous with the ongoing
associative thought process. The autonomous dynamics needs a long-term
working-point optimization which acquires within the dHAN concept a dual
functionality: It stabilizes the time development of the associative thought
process and limits runaway synaptic growth, which generically occurs otherwise
in neural networks with self-induced activities and Hebbian-type learning
rules
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