Search results for "modeling"
showing 10 items of 4489 documents
Ontology Views for Ontology Change Management
2014
International audience; In the literature, ontology change management systems (OCMS) are direct implementation of the concept of “change management” stated by reference (Klein, 2004). Ontology change management combines ontol- ogy evolution and versioning features to manage ontol- ogy changes and their impacts. Since 2007, many works have combined ontology evolution and versioning into ontology change management systems (OCMS). The evolution subject has been massively studied in these works. They especially addressed the consistence issue for the application of changes on the ontology. These proposals constituted a consequent background for ontology change management but they did not take i…
Traitement 3D de nuages de points basé sur la connaissance
2013
The modeling of real-world scenes through capturing 3D digital data has proven to be both useful andapplicable in a variety of industrial and surveying applications. Entire scenes are generally capturedby laser scanners and represented by large unorganized point clouds possibly along with additionalphotogrammetric data. A typical challenge in processing such point clouds and data lies in detectingand classifying objects that are present in the scene. In addition to the presence of noise, occlusionsand missing data, such tasks are often hindered by the irregularity of the capturing conditions bothwithin the same dataset and from one data set to another. Given the complexity of the underlying…
A Decentralized Ontology Versioning Model Designed for Inter-operability and Multi-organizational Data Exchange
2021
Current information systems operated in a multi-organization context use centralized or hierarchical data models proven inefficient as the network’s scale rapidly increases. The introduction of blockchain and decentralized specific mechanisms stimulate the use of ontology-based data models. While the adoption of blockchain as a communication medium facilitates the communication and data exchange in a more reliably and securely fashion, this opens new challenges regarding the evolution and versioning of the ontology. This paper proposes a versioning mechanism tailored to the decentralized environment. It provides the conceptual building blocks allowing an ontology to evolve under the supervi…
VAMPIRE: Vessel assessment and measurement platform for images of the REtina
2011
We present VAMPIRE, a software application for efficient, semi-automatic quantification of retinal vessel properties with large collections of fundus camera images. VAMPIRE is also an international collaborative project of four image processing groups and five clinical centres. The system provides automatic detection of retinal landmarks (optic disc, vasculature), and quantifies key parameters used frequently in investigative studies: vessel width, vessel branching coefficients, and tortuosity. The ultimate vision is to make VAMPIRE available as a public tool, to support quantification and analysis of large collections of fundus camera images.
Wave Propagation in a 3-D Optical Waveguide
2003
In this paper we study the problem of wave propagation in a 3-D optical fiber. The goal is to obtain a solution for the time-harmonic field caused by a source in a cylindrically symmetric waveguide. The geometry of the problem, corresponding to an open waveguide, makes the problem challenging. To solve it, we construct a transform theory which is a nontrivial generalization of a method for solving a 2-D version of this problem given by Magnanini and Santosa.\cite{MS} The extension to 3-D is made complicated by the fact that the resulting eigenvalue problem defining the transform kernel is singular both at the origin and at infinity. The singularities require the investigation of the behavio…
Guideline for Optical Optimization of Planar Perovskite Solar Cells
2019
Organometallic halide perovskite solar cells have emerged as a versatile photovoltaic technology with soaring efficiencies. Planar configuration in particular, has been a structure of choice thanks to its lower temperature processing, compatibility with tandem solar cells and potential in commercialization. Despite all the breakthroughs in the field, the optical mechanisms leading to highly efficient perovskite solar cells lack profound insight. In this paper, a comprehensive guideline is introduced involving semi-analytical equations for thickness optimization of the front and rear transport layers, perovskite, and transparent conductive oxides to improve the antireflection and light trapp…
The application of AI techniques in the optimal design of multi-pass cold drawing processes
2001
Abstract In the paper the problem of optimal pass schedule design in multi-pass wire drawing process is investigated. An automatic design procedure based on an effective artificial intelligence (AI) technique, namely simulated annealing (SA), is proposed. The developed algorithm is aimed to achieve a satisfactory balance of the drawing stresses on the material along the reduction sequence, maintaining in the meantime the drawing stress at each pass below a safety value. In this way both the optimal number of passes and the optimal drawing sequence are determined. The effectiveness of the design procedure is tested through the comparison of the sequences suggested by the algorithm with a set…
Optimum design and operation of primary sludge fermentation schemes for volatile fatty acids production.
2003
This paper presents a model-knowledge based algorithm for optimising the primary sludge fermentation process design and operation. This is a recently used method to obtain the volatile fatty acids (VFA), needed to improve biological nutrient removal processes, directly from the raw wastewater. The proposed algorithm consists in a heuristic reasoning algorithm based on the expert knowledge of the process. Only effluent VFA and the sludge blanket height (SBH) have to be set as design criteria, and the optimisation algorithm obtains the minimum return sludge and waste sludge flow rates which fulfil those design criteria. A pilot plant fed with municipal raw wastewater was operated in order to …
A multicriterion design of steel frames with shakedown constraints
2006
The minimum volume design of elastic perfectly plastic steel frames subjected to fixed and cyclic loads is searched in such a way that the structure remains in elastic field in serviceability conditions, while it is subjected to alternating plasticity under very strong cyclic actions, incremental and instantaneous collapse being prevented. The problem is faced on the grounds of a statical and a kinematical approach. The Kuhn-Tucker conditions of the two problems prove that they are each one the dual of the other and provide useful pieces of information about the structural behaviour. Numerical applications confirm the theoretical expectations: optimal designs turn out to be quite light, wit…
Discrete variable design of frames subjected to seismic actions accounting for element slenderness
2015
An optimal design problem formulation of elastic plastic frames under different combinations of fixed and seismic loads is presented. The optimal structure must behave elastically for the fixed loads, shakedown for serviceability conditions and prevent instantaneous collapse for fixed and high seismic loads. P-Delta effects and element buckling are considered. An appropriate modal technique is utilized. The design variables can have components in a continuous field or, alternatively, in chosen discrete sets or, yet, both kind of variables can be present. The design problem is formulated on the ground of a statical approach. The applications are related to steel frames.