402 research outputs found
Automated generation of geometrically-precise and semantically-informed virtual geographic environnements populated with spatially-reasoning agents
La Géo-Simulation Multi-Agent (GSMA) est un paradigme de modélisation et de simulation de phénomènes dynamiques dans une variété de domaines d'applications tels que le domaine du transport, le domaine des télécommunications, le domaine environnemental, etc. La GSMA est utilisée pour étudier et analyser des phénomènes qui mettent en jeu un grand nombre d'acteurs simulés (implémentés par des agents) qui évoluent et interagissent avec une représentation explicite de l'espace qu'on appelle Environnement Géographique Virtuel (EGV). Afin de pouvoir interagir avec son environnement géographique qui peut être dynamique, complexe et étendu (à grande échelle), un agent doit d'abord disposer d'une représentation détaillée de ce dernier. Les EGV classiques se limitent généralement à une représentation géométrique du monde réel laissant de côté les informations topologiques et sémantiques qui le caractérisent. Ceci a pour conséquence d'une part de produire des simulations multi-agents non plausibles, et, d'autre part, de réduire les capacités de raisonnement spatial des agents situés. La planification de chemin est un exemple typique de raisonnement spatial dont un agent pourrait avoir besoin dans une GSMA. Les approches classiques de planification de chemin se limitent à calculer un chemin qui lie deux positions situées dans l'espace et qui soit sans obstacle. Ces approches ne prennent pas en compte les caractéristiques de l'environnement (topologiques et sémantiques), ni celles des agents (types et capacités). Les agents situés ne possèdent donc pas de moyens leur permettant d'acquérir les connaissances nécessaires sur l'environnement virtuel pour pouvoir prendre une décision spatiale informée. Pour répondre à ces limites, nous proposons une nouvelle approche pour générer automatiquement des Environnements Géographiques Virtuels Informés (EGVI) en utilisant les données fournies par les Systèmes d'Information Géographique (SIG) enrichies par des informations sémantiques pour produire des GSMA précises et plus réalistes. De plus, nous présentons un algorithme de planification hiérarchique de chemin qui tire avantage de la description enrichie et optimisée de l'EGVI pour fournir aux agents un chemin qui tient compte à la fois des caractéristiques de leur environnement virtuel et de leurs types et capacités. Finalement, nous proposons une approche pour la gestion des connaissances sur l'environnement virtuel qui vise à supporter la prise de décision informée et le raisonnement spatial des agents situés
Archaeological 3D GIS
Archaeological 3D GIS provides archaeologists with a guide to explore and understand the
unprecedented opportunities for collecting, visualising, and analysing archaeological
datasets in three dimensions.
With platforms allowing archaeologists to link, query, and analyse in a virtual, georeferenced
space information collected by different specialists, the book highlights how
it is possible to re-think aspects of theory and practice which relate to GIS. It explores
which questions can be addressed in such a new environment and how they are going
to impact the way we interpret the past. By using material from several international
case studies such as Pompeii, Çatalhöyük, as well as prehistoric and protohistoric sites
in Southern Scandinavia, this book discusses the use of the third dimension in support
of archaeological practice.
This book will be essential for researchers and scholars who focus on archaeology and
spatial analysis, and is designed and structured to serve as a textbook for GIS and digital
archaeology courses
Archaeological 3D GIS
Archaeological 3D GIS provides archaeologists with a guide to explore and understand the
unprecedented opportunities for collecting, visualising, and analysing archaeological
datasets in three dimensions.
With platforms allowing archaeologists to link, query, and analyse in a virtual, georeferenced
space information collected by different specialists, the book highlights how
it is possible to re-think aspects of theory and practice which relate to GIS. It explores
which questions can be addressed in such a new environment and how they are going
to impact the way we interpret the past. By using material from several international
case studies such as Pompeii, Çatalhöyük, as well as prehistoric and protohistoric sites
in Southern Scandinavia, this book discusses the use of the third dimension in support
of archaeological practice.
This book will be essential for researchers and scholars who focus on archaeology and
spatial analysis, and is designed and structured to serve as a textbook for GIS and digital
archaeology courses
Archaeological 3D GIS
"Archaeological 3D GIS provides archaeologists with a guide to explore and understand the unprecedented opportunities for collecting, visualising, and analysing archaeological datasets in three dimensions.
With platforms allowing archaeologists to link, query, and analyse in a virtual, georeferenced space information collected by different specialists, the book highlights how it is possible to re-think aspects of theory and practice which relate to GIS. It explores which questions can be addressed in such a new environment and how they are going to impact the way we interpret the past. By using material from several international case studies such as Pompeii, Çatalhöyük, as well as prehistoric and protohistoric sites in Southern Scandinavia, this book discusses the use of the third dimension in support of archaeological practice.
This book will be essential for researchers and scholars who focus on archaeology and spatial analysis, and is designed and structured to serve as a textbook for GIS and digital archaeology courses.
Economic aspects of additive manufacturing: benefits, costs and energy consumption
Additive Manufacturing (AM) refers to the use of a group of technologies capable of combining material layer-by-layer to manufacture geometrically complex products in a single digitally controlled process step, entirely without moulds, dies or other tooling. AM is a parallel manufacturing approach, allowing the contemporaneous production of multiple, potentially unrelated, components or products. This thesis contributes to the understanding of the economic aspects of additive technology usage through an analysis of the effect of AM s parallel nature on economic and environmental performance measurement. Further, this work assesses AM s ability to efficiently create complex components or products.
To do so, this thesis applies a methodology for the quantitative analysis of the shape complexity of AM output. Moreover, this thesis develops and applies a methodology for the combined estimation of build time, process energy flows and financial costs. A key challenge met by this estimation technique is that results are derived on the basis of technically efficient AM operation.
Results indicate that, at least for the technology variant Electron Beam Melting, shape complexity may be realised at zero marginal energy consumption and cost. Further, the combined estimator of build time, energy consumption and cost suggests that AM process efficiency is independent of production volume. Rather, this thesis argues that the key to efficient AM operation lies in the user s ability to exhaust the available build space
Internationales Kolloquium über Anwendungen der Informatik und Mathematik in Architektur und Bauwesen : 20. bis 22.7. 2015, Bauhaus-Universität Weimar
The 20th International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering will be held at the Bauhaus University Weimar from 20th till 22nd July 2015. Architects, computer scientists, mathematicians, and engineers from all over the world will meet in Weimar for an interdisciplinary exchange of experiences, to report on their results in research, development and practice and to discuss. The conference covers a broad range of research areas: numerical analysis, function theoretic methods, partial differential equations, continuum mechanics, engineering applications, coupled problems, computer sciences, and related topics. Several plenary lectures in aforementioned areas will take place during the conference.
We invite architects, engineers, designers, computer scientists, mathematicians, planners, project managers, and software developers from business, science and research to participate in the conference
Computer recognition of occluded curved line drawings
A computer program has been designed to interpret scenes from PEANUTS
cartoons, viewing each scene as a two-dimensional representation of
an event in the three-dimensional world. Characters are identified
by name, their orientation and body position is described, and their
relationship to other objects in the scene is indicated. This
research is seen as an investigation of the problems in recognising
flexible non-geometric objects which are subject to self-occlusion as
well as occlusion by other objects. A hierarchy of models containing both shape and relational
information has been developed to deal with the flexible cartoon
bodies. Although the region is the basic unit used in the analysis,
the hierarchy makes use of intermediate models to group individual
regions into larger more meaningful functional units. These
structures may be shared at a higher level in the hierarchy.
Knowledge of model similarities may be applied to select alternative
models and conserve some results of an incorrect model application.
The various groupings account for differences among the characters or
modifications in appearance due to changes in attitude. Context
information plays a key role in the selection of models to deal with
ambiguous shapes. By emphasising relationships between regions, the
need for a precise description of shape is reduced. Occlusion interferes with the model-based analysis by obscuring the
essential features required by the models. Both the perceived shape
of the regions and the inter-relationships between them are altered.
An heuristic based on the analysis of line junctions is used to
confirm occlusion as the cause of the failure of a model-to-region
match. This heuristic, an extension of the T-joint techniques of
polyhedral domains, deals with "curved" junctions and can be applied
to cases of multi-layered occlusion. The heuristic was found to be
most effective in dealing with occlusion between separate objects;
standard instances of self-occlusion were more effectively handled at
the model level. This thesis describes the development of the program, structuring the
discussion around three main problem areas: models, occlusion, and
the control aspects of the system. Relevant portions of the
programs analyses are used to illustrate each problem area
3D Object Recognition Based On Constrained 2D Views
The aim of the present work was to build a novel 3D object recognition system capable of classifying
man-made and natural objects based on single 2D views. The approach to this problem
has been one motivated by recent theories on biological vision and multiresolution analysis. The
project's objectives were the implementation of a system that is able to deal with simple 3D
scenes and constitutes an engineering solution to the problem of 3D object recognition, allowing
the proposed recognition system to operate in a practically acceptable time frame.
The developed system takes further the work on automatic classification of marine phytoplank-
(ons, carried out at the Centre for Intelligent Systems, University of Plymouth. The thesis discusses
the main theoretical issues that prompted the fundamental system design options. The
principles and the implementation of the coarse data channels used in the system are described.
A new multiresolution representation of 2D views is presented, which provides the classifier
module of the system with coarse-coded descriptions of the scale-space distribution of potentially
interesting features. A multiresolution analysis-based mechanism is proposed, which directs
the system's attention towards potentially salient features. Unsupervised similarity-based
feature grouping is introduced, which is used in coarse data channels to yield feature signatures
that are not spatially coherent and provide the classifier module with salient descriptions of object
views. A simple texture descriptor is described, which is based on properties of a special wavelet
transform.
The system has been tested on computer-generated and natural image data sets, in conditions
where the inter-object similarity was monitored and quantitatively assessed by human subjects,
or the analysed objects were very similar and their discrimination constituted a difficult task even
for human experts. The validity of the above described approaches has been proven. The studies
conducted with various statistical and artificial neural network-based classifiers have shown that
the system is able to perform well in all of the above mentioned situations. These investigations
also made possible to take further and generalise a number of important conclusions drawn during
previous work carried out in the field of 2D shape (plankton) recognition, regarding the behaviour
of multiple coarse data channels-based pattern recognition systems and various classifier
architectures.
The system possesses the ability of dealing with difficult field-collected images of objects and
the techniques employed by its component modules make possible its extension to the domain
of complex multiple-object 3D scene recognition. The system is expected to find immediate applicability
in the field of marine biota classification
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