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梁振邦 and Chun-bong Leung. "Conversion of features for CAD/CAM integration." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31237290.
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Leung, Chun-bong. "Conversion of features for CAD/CAM integration /." Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19634961.
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林世銘 and Sai-ming Lam. "Recognition of machining features: a hybrid approach." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31240458.
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Lam, Sai-ming. "Recognition of machining features : a hybrid approach /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2160745X.
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Straube, Dima [Verfasser]. "CAD-Features für die Entwicklung von Mikrosystemen / Dima Straube." München : Verlag Dr. Hut, 2011. http://d-nb.info/1013526147/34.
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Blattman, William R. "Generating CAD Parametric Features Based on Topology Optimization Results." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2367.pdf.
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King, Matthew Lee. "A CAD-centric Approach to CFD Analysis With Discrete Features." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd570.pdf.
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Holland, Peter. "A CAD module for the extraction of geometric features from STEP files." Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430626.
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Shumway, Devin James. "Hybrid State-Transactional Database for Product Lifecycle Management Features in Multi-Engineer Synchronous Heterogeneous Computer-Aided Design." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6341.
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There are many different programs that can perform Computer Aided Design (CAD). In order for these programs to share data, file translations need to occur. These translations have typically been done by IGES and STEP files. With the work done at the BYU CAD Lab to create a multi-engineer synchronous heterogeneous CAD environment, these translation processes have become synchronous by using a server and a database to manage the data. However, this system stores part data in a database. The data in the database cannot be used in traditional Product Lifecycle Management systems. In order to remedy this, a new database was developed that enables every edit made in a CAD part across multiple CAD systems to be stored as well as worked on simultaneously. This allows users to access every action performed in a part. Branching was introduced to the database which allows users to work on multiple configurations of a part simultaneously and reduces file save sizes for different configurations by 98.6% compared to those created by traditional CAD systems.
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Silva, Narciso Antonio da. "Aplicação de conceitos de tecnologia de grupo e modelamento baseado em features para integração de informações de projeto e manufatura." [s.n.], 1998. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265660.
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Orientador: Antonio BatocchioDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-07-23T16:05:59Z (GMT). No. of bitstreams: 1 Silva_NarcisoAntonioda_M.pdf: 13695611 bytes, checksum: e1b0368d3bd0b39da00972e718b64524 (MD5) Previous issue date: 1998
Resumo: A utilização de recursos assistidos por computadores como sistemas CAD/CAM e máquinas CNC tem se tomado bastante acentuada no ambiente industrial, propiciando uma série de vantagens aos seus usuários. Em contrapartida, essa utilização também pode incorrer em problemas, como o surgimento de pontos isolados com alto índice de eficiência local, mas que não agregam valor às operações das empresas, principalmente em função da dificuldade de integrar as informações que são geradas e compartilhadas pelas áreas de manufatura. Este trabalho apresenta um modelo conceitual, orientado às necessidades de um fabricante hipotético de máquinas e equipamentos sob encomenda, como uma das formas de melhorar a integração das informações geradas durante a fase de Projeto e que são compartilhadas com outras áreas vinculadas à Manufatura do produto, permitindo a formação de um Banco de Dados comum. Tal modelo utiliza os conceitos de Tecnologia de Grupo e Projeto baseado em Features, sendo que um aplicativo para modelamento CAD (2D) foi desenvolvido para demonstrar sua utilização. A simulação dos resultados obtidos permite verificar a possibilidade de obtenção de melhorias na integração das informações compartilhadas, redução de atividades que não agregam valor ao produto e menor dependência da experiência e intervenção humana para realização de algumas atividades
Abstract: The use of Computer Aided systems such as CAD/CAM and NC machines have been established in the industrial environment as standard because of their ability to increase productivity and quality. But such systems can also be a source of problems if there is not enough attention for the integration of the informations that are shared by the manufacturing areas, which will lead to the growth of"automation islands". This paper presents a conceptual model, oriented to the needs of a hypothetical machine manufacturer, as a method to improve the integration of Design and Manufacturing data and to allow for a common data base formation. This model uses concepts from Group Technology (GT) and Feature-based Modeling methodologies. A sofiware was developed to design 2D rotational parts in a CAD system environment. Afier simulating the use of the presented model the following benefits were achieved: integration of shared informations, reduction of activities that do not agregate value to the product and less dependency on human experience in some activities
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
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Staves, Daniel Robert. "Associative CAD References in the Neutral Parametric Canonical Form." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6222.
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Due to the multiplicity of computer-aided engineering applications present in industry today, interoperability between programs has become increasingly important. A survey conducted among top engineering companies found that 82% of respondents reported using 3 or more CAD formats during the design process. A 1999 study by the National Institute for Standards and Technology (NIST) estimated that inadequate interoperability between the OEM and its suppliers cost the US automotive industry over $1 billion per year, with the majority spent fixing data after translations. The Neutral Parametric Canonical Form (NPCF) prototype standard developed by the NSF Center for e-Design, BYU Site offers a solution to the translation problem by storing feature data in a CAD-neutral format to offer higher-fidelity parametric transfer between CAD systems. This research has focused on expanding the definitions of the NPCF to enforce data integrity and to support associativity between features to preserved design intent through the neutralization process. The NPCF data structure schema was defined to support associativity while maintaining data integrity. Neutral definitions of new features was added including multiple types of coordinate systems, planes and axes. Previously defined neutral features were expanded to support new functionality and the software architecture was redefined to support new CAD systems. Complex models have successfully been created and exchanged by multiple people in real-time to validated the approach of preserving associativity and support for a new CAD system, PTC Creo, was added.
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Freeman, Robert Steven. "Neutral Parametric Canonical Form for 2D and 3D Wireframe CAD Geometry." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5688.
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The challenge of interoperability is to retain model integrity when different software applications exchange and interpret model data. Transferring CAD data between heterogeneous CAD systems is a challenge because of differences in feature representation. A study by the National Institute for Standards and Technology (NIST) performed in 1999 made a conservative estimate that inadequate interoperability in the automotive industry costs them $1 billion per year. One critical part of eliminating the high costs due to poor interoperability is a neutral format between heterogeneous CAD systems. An effective neutral CAD format should include a current-state data store, be associative, include the union of CAD features across an arbitrary number of CAD systems, maintain design history, maintain referential integrity, and support multi-user collaboration. This research has focused on extending an existing synchronous collaborative CAD software tool to allow for a neutral, current-state data store. This has been accomplished by creating a Neutral Parametric Canonical Form (NPCF) which defines the neutral data structure for many basic CAD features to enable translation between heterogeneous CAD systems. The initial architecture developed begins to define a new standard for storing CAD features neutrally. The NPCF's for many features have been implemented in a multi-user interoperability program and work between NX and CATIA CAD systems. The 2D point, 2D line, 2D arc, 2D circle, 2D spline, 3D point, extrude, and revolve NPCF's will be specifically defined. Complex models have successfully been modeled and exchanged in real time and have validated the NPCF approach. Multiple users can be in the same part at the same time in different CAD systems and create and update models in real time.
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Silva, Júnior Alvino Cesário da. "Uma abordagem para criação e compartilhamento de dados de peças através da integração CAD-RDBMS." Florianópolis, SC, 2001. http://repositorio.ufsc.br/xmlui/handle/123456789/81723.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia MecânicaMade available in DSpace on 2012-10-19T07:11:42Z (GMT). No. of bitstreams: 0Bitstream added on 2014-09-25T22:29:03Z : No. of bitstreams: 1 179132.pdf: 6860134 bytes, checksum: d791e203cb89b920370d1ee84d9b2e43 (MD5)
As estratégia atuais de desenvolvimento de produtos compartilham um requisito fundamental: a necessidade de ferramentas computacionais capazes de integrar e coodenar requisitos de projeto durante as atividades de modelamento de produtos. Vários estudo nesta área, apontam para a integração de feramentas de sistemas CAD comerciais com outras tecnologias de informação. Isso permite combinar e compartilhar de maneira centralizada, dados gerados por sistemas computacionai empregados nas diferentes áreas de conhecimento da empresa. O presente trabalho segue esta linha de pesquisa. Ele propõe uma abordagem para modelamento de peças mecânicas na fase de detalhamento de projeto, utilizando uma biblioteca com definições de features personalizadas. Tais definições são entendidas como unidades informacionais reusáveis de projeto, constituidas de dados geométricos e não geométricos. Elas são representadas através da combinação de recursos de sistemas CAD comerciais de médio ou grande porte, com RDBMS. O obejetivo é demonstrar pontencialidades e limitações na utilização das ferramentas disponíveis nestes sistemas CAD, para o desenvolvimento de aplicações baseadas na tecnologia de features. É apresentada uma revisão do estado da arte em sistemas CAD e RDBMS comerciais, descrição da abordagem proposta, e sua implementação prática. A abordagem proposta integra informações de engenharia no projeto mecânico para criação de modelos mais completos de peças e também facilita o compartilhamento destes dados. Portanto, ela pode ser usada como base de implementação de um ambiente computacional para Engenharia Simultânea. A reusabilidade de dados possibilita o trabalho com dados de projeto já otimizados, segundo considerações de manufaturabilidade, montabilidade, etc., favorecendo assim a padronização, redução de tempo e custo no desenvolvimento de produtos.
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Maziero, Nilson Luiz. "Um sistema computacional inteligente de suporte ao projeto, manufatura e montagem de peças baseado em features :: uma abordagem com sistemas especialistas /." Florianópolis, SC, 1998. http://repositorio.ufsc.br/xmlui/handle/123456789/77719.
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Tese (Doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico.Made available in DSpace on 2012-10-17T06:52:53Z (GMT). No. of bitstreams: 0Bitstream added on 2016-01-09T00:28:08Z : No. of bitstreams: 1 142447.pdf: 18276024 bytes, checksum: f501e693472845b2529a876dcae980b9 (MD5)
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Patrocinio, Ana Claudia. "Classificador automático de achados mamográficos em imagens digitais de mamas densas utilizando técnicas híbridas." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/18/18133/tde-16022016-123302/.
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Esta tese apresenta uma metodologia para classificação automática de achados mamográficos em mamas densas através de uma abordagem híbrida de classificadores e extração de atributos, como parte de um esquema computadorizado de auxílio ao diagnóstico (CAD) para mamografia. Foram implementadas duas redes Backpropagation. Uma responde pela classificação de clusters de microcalcificações, através de atributos descritores geométricos, em duas classes - suspeito e não suspeito. A outra rede classifica nódulos utilizando descritores geométricos e uma entrada com informação extraída de atributos de intensidade, produzindo na saída dois tipos de informação: presença ou não do nódulo, e constatada a presença do nódulo, classificação da região de interesse (RI) entre as categorias BI-RADS. As respostas de um \"clusterizador\" de RIs através de atributos de intensidade serviram de entrada para essa rede fornecendo uma informação de grau de densidade da RI. Uma interface foi desenvolvida para a apresentação dos resultados a fim de fornecer informações mais detalhadas da classificação e do caso analisado. Os resultados do classificador foram analisados através de análise estatística de sensibilidade e especificidade, e também por curvas ROC. Os resultados obtidos ficaram próximos a 89% de acerto total (verdadeiros-positivos mais verdadeiros-negativos) para nódulos produzindo valor de Az superior a 0,92 e ultrapassaram 75% de acerto da classificação entre as classes BI-RADS. Na classificação dos clusters os acertos totais do classificador ficaram próximos de 90%, com Az superior a 0,94. Para ambos tipos de lesões, as taxas de respostas falsas-negativas ficaram abaixo de 0,1, o que significa baixo erro em relação à não detecção da doença quando o sinal está presente. O classificador apresentado nesse trabalho é a conclusão de uma etapa importante do esquema CAD que vem sendo desenvolvido pelo grupo, além de possibilitar a disponibilização de mais uma ferramenta automática de auxílio ao diagnóstico do câncer de mama aos serviços de mamografia.This thesis presents a methodology for automatic classification of mamographic findings in image of dense breast through hybrid approach of classifiers and features extraction techniques, as part of a computer-aided diagnostic (CAD) scheme for mammography. Two Backpropagation neural networks were implemented. One for microcalcifications clustered classification, through geometric descriptors, in two classes - suspect and non-suspect. The other neural network classifies nodules using geometric descriptors and additional information from intensity features extracted, producing in the output two kinds of information: presence or not of the nodule, and if nodule is present in the image, classification among BI-RADS categories. The result of clustering technique by using intensity features is presented as a new input to neural network, supplying density degree of image. An interface was developed for results presentation in order to supply more detailed information from the classifier outputs and of the analyzed case. The results of the classifier were analyzed through sensibility and specificity statistical analysis, and also for ROC curves. The results were close to 89% of total accuracy (positive-true plus negative-true) for nodules producing value of Az more than 0,92 and 75% of accuracy to classification among BI-RADS categories. In the cluster classification the total accuracy is about 90%, and Az greater than 0,94. In both kinds of lesions, negative-false result rates were below 0,1, which means low error related to the fail to detect the disease when the signal is present. The classifier presented in this work is the conclusion of an important stage of the CAD scheme that has been developed by the group, besides making possible the availability of one more automatic tool of aid to the breast cancer diagnosis to be used in mammography centers.
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Abdul, Ghafour Samer. "Interopérabilité sémantique des connaissances des modèles de produits à base de features." Phd thesis, Université Claude Bernard - Lyon I, 2009. http://tel.archives-ouvertes.fr/tel-00688098.
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Dans un environnement collaboratif de développement de produit, plusieurs acteurs, ayant différents points de vue et intervenant dans plusieurs phases du cycle de vie de produit, doivent communiquer et échanger des connaissances entre eux. Ces connaissances, existant sous différents formats hétérogènes, incluent potentiellement plusieurs concepts tels que l'historique de conception, la structure du produit, les features, les paramètres, les contraintes, et d'autres informations sur le produit. Les exigences industrielles de réduction du temps et du coût de production nécessitent l'amélioration de l'interopérabilité sémantique entre les différents processus de développement afin de surmonter ces problèmes d'hétérogénéité tant au niveau syntaxique, structurel, que sémantique. Dans le domaine de la CAO, la plupart des méthodes existantes pour l'échange de données d'un modèle de produit sont, effectivement, basées sur le transfert des données géométriques. Cependant, ces données ne sont pas suffisantes pour saisir la sémantique des données, telle que l'intention de conception, ainsi que l'édition des modèles après leur échange. De ce fait, nous nous sommes intéressés à l'échange des modèles " intelligents ", autrement dit, définis en termes d'historique de construction, de fonctions intelligentes de conception appelées features, y compris les paramètres et les contraintes. L'objectif de notre thèse est de concevoir des méthodes permettant d'améliorer l'interopérabilité sémantique des systèmes CAO moyennant les technologies du Web Sémantique comme les ontologies OWL DL et le langage des règles SWRL. Nous avons donc élaboré une approche d'échange basée sur une ontologie commune de features de conception, que nous avons appelée CDFO " Common Design Features Ontology ", servant d'intermédiaire entre les différents systèmes CAO. Cette approche s'appuie principalement sur deux grandes étapes. La première étape consiste en une homogénéisation des formats de représentation des modèles CAO vers un format pivot, en l'occurrence OWL DL. Cette homogénéisation sert à traiter les hétérogénéités syntaxiques entre les formats des modèles. La deuxième étape consiste à définir des règles permettant la mise en correspondance sémantique entre les ontologies d'application de CAO et notre ontologie commune. Cette méthode de mise en correspondance se base principalement, d'une part, sur la définition explicite des axiomes et des règles de correspondance permettant l'alignement des entités de différentes ontologies, et d'autre part sur la reconnaissance automatique des correspondances sémantiques supplémentaires à l'aide des capacités de raisonnement fournies par les moteurs d'inférence basés sur les logiques de description. Enfin, notre méthode de mise en correspondance est enrichie par le développement d'une méthode de calcul de similarité sémantique appropriée pour le langage OWL DL, qui repose principalement sur les composants des entités en question tels que leur description et leur contexte.
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黃景維 and King-wei Wong. "An intelligent object-oriented feature-based system for CAD/CAM integration." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1994. http://hub.hku.hk/bib/B30098774.
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Wong, King-wei. "An intelligent object-oriented feature-based system for CAD/CAM integration /." Hong Kong : University of Hong Kong, 1994. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20667528.
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Ceran, Murat. "Parametric human spine modelling." Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/7958.
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3-D computational modelling of the human spine provides a sophisticated and cost-effective medium for bioengineers, researchers, and ergonomics designers in order to study the biomechanical behaviour of the human spine under different loading conditions. Developing a generic parametric computational human spine model to be employed in biomechanical modelling introduces a considerable potential to reduce the complexity of implementing and amending the intricate spinal geometry. The main objective of this research is to develop a 3-D parametric human spine model generation framework based on a command file system, by which the parameters of each vertebra are read from the database system, and then modelled within commercial 3-D CAD software. A novel data acquisition and generation system was developed as a part of the framework for determining the unknown vertebral dimensions, depending on the correlations between the parameters estimated from existing anthropometrical studies in the literature. The data acquisition system embodies a predictive methodology that comprehends the relations between the features of the vertebrae by employing statistical and geometrical techniques. Relations amongst vertebral parameters such as golden ratio were investigated and successfully implemented into the algorithms. The validation of the framework was carried out by comparing the developed 3-D computational human spine models against various real life human spine data, where good agreements were achieved. The constructed versatile framework possesses the capability to be utilised as a basis for quickly and effectively developing biomechanical models of the human spine such as finite element models.
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Sheik, Meeran A. "Automated feature recognition from 2D CAD models." Thesis, Cranfield University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281227.
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Tam, Ka-wing. "Feature based reverse engineering for thermoforming mould design /." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B36537196.
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Tam, Ka-wing, and 譚家榮. "Feature based reverse engineering for thermoforming mould design." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B36537196.
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Niu, Zhibin. "Declarative CAD feature recognition : an efficient approach." Thesis, Cardiff University, 2015. http://orca.cf.ac.uk/86873/.
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Feature recognition aids CAD model simplification in engineering analysis and machining path in manufacturing. In the domain of CAD model simplification, classic feature recognition approaches face two challenges: 1) insufficient performances; 2) engineering features are diverse, and no system can hard-code all possible features in advance. A declarative approach allows engineers to specify new features without having to design algorithms to find them. However, naive translation of declarations leads to executable algorithms with high time complexity. Inspired by relational database management systems (RDBMS), I suppose that if there exists a way to turn a feature declaration into an SQL query that is further processed by a database engine interfaced to a CAD modeler, the optimizations can be utilized for “free”. Testbeds are built to verify the idea. Initially, I devised a straightforward translator to turn feature declarations into queries. Experiments on SQLite show it gives a quasiquadratic performance for common features. Then it is extended with a new translator and PostgreSQL. In the updated version, I have made a significant breakthrough – my approach is the first to achieve linear time performance with respect to model size for common features, and acceptable times for real industrial models. I learn from the testbeds that PostgreSQL uses hash joins reduce the search space enable a fast feature finding. Besides, I have further improved the performance by: (i) lazy evaluation, which can be used to reduce the workload on the CAD modeler, and (ii) predicate ordering, which reorders the query plan by taking into account the time needed to compute various geometric operations. Experimental results are presented to validate their benefits.
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Gandhi, Ashit R. "Feature-based geometric modeling using B-spline surfaces and a natural language approach." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54359.
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Traditionally, design geometries are represented using orthographic views which require a human being to interpret them and recognize geometric features to evaluate the design. Solid modeling systems have made the task somewhat easier, but they often require tedious and complex operations using simple geometric primitives. This has led to investigation of modeling systems which allow the creation of assemblies the way engineers conceive them - as features.
To be able to efficiently describe models in terms of features, a rich set of feature descriptors are necessary. An exhaustive study of English words describing form, shape, feature, shape altering transformations and surface conditions was done to establish a wide vocabulary for feature based description. Classification based on topology and form was done and prototype constraint relations were implemented to differentiate between some features. A feature is created from a topological group by computing points and interpolating them with uniform rational B-spline patches. Control points needed to compute the patches are computed from the interpolation points by an inverse relation. A designer-oriented modeling language, based on simple English syntax, was devised to specify procedures to be executed by the modeler in order to create features using minimal user input.Ph. D.
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Scott, Nathan W. "High-level, Product Type-specific Programmatic Operations for Streamlining Associative Computer-aided Design." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2601.pdf.
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Sivakumar, Krish. "CAD feature development and abstraction for process planning." Ohio : Ohio University, 1994. http://www.ohiolink.edu/etd/view.cgi?ohiou1180038784.
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Chaharbaghi, H. "Feature based design : integration of CAD and CAM." Thesis, University of Edinburgh, 1992. http://hdl.handle.net/1842/14321.
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The product model is the primary source of input for a process planning system. The basic requirement of a product modeller in the area of Generative Computer-Aided Process Planning (GCAPP) is to generate a complete, exact, unambiguous 3D product representation which is directly accessible to automated planning. Such a product representation must include geometry, material specification, surface finish data, features and their relationship to other features, and tolerances. The product representation has to be complete, since in an automated environment interactive input of missing information at a later stage has to be avoided. Automation of process planning requires the product data to be extracted from the product model without human interaction. With respect to the above requirements a principle called Feature Based Design has been investigated and developed. This method provides a part description at the design stage which is suitable for a GCAPP system. If a fully automated GCAPP is consolidated to the system a real integration of CAD and CAM will be achieved, which will support simultaneous engineering philosophy as well as providing a true foundation for CIM.
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Brousseau, Emmanuel. "Intelligent techniques for automatic feature recognition in CAD models." Thesis, Cardiff University, 2005. http://orca.cf.ac.uk/55422/.
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Tessier, Sean Michael. "Ontology-based approach to enable feature interoperability between CAD systems." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41118.
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Data interoperability between computer-aided design (CAD) systems remains a major obstacle in the information integration and exchange in a collaborative engineering environment. The standards for CAD data exchange have remained largely restricted to geometric representations, causing the design intent portrayed through construction history, features, parameters, and constraints to be discarded in the exchange process. In this thesis, an ontology-based framework is proposed to allow for the full exchange of semantic feature data. A hybrid ontology approach is proposed, where a shared base ontology is used to convey the concepts that are common amongst different CAD systems, while local ontologies are used to represent the feature libraries of individual CAD systems as combinations of these shared concepts. A three-branch CAD feature model is constructed to reduce ambiguity in the construction of local ontology feature data. Boundary representation (B-Rep) data corresponding to the output of the feature operation is incorporated into the feature data to enhance data exchange.
The Ontology Web Language (OWL) is used to construct a shared base ontology and a small feature library, which allows the use of existing ontology reasoning tools to infer new relationships and information between heterogeneous data. A combination of OWL and SWRL (Semantic Web Rule Language) rules are developed to allow a feature from an arbitrary source system expressed via the shared base ontology to be automatically classified and translated into the target system. These rules relate input parameters and reference types to expected B-Rep objects, allowing classification even when feature definitions vary or when little is known about the source system. In cases when the source system is well known, this approach also permits direct translation rules to be implemented. With such a flexible framework, a neutral feature exchange format could be developed.
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Zhu, Cheng-Feng. "CAD/CSPP/CAM integration using feature-based component data model." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362993.
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Stolt, Roland. "CAD-Model Parsing for Automated Design and Design Evaluation." Doctoral thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH. Forskningsområde Datorstödd konstruktion, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-10700.
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Product development has both innovative and analytic sides. Starting from the requirements, a design suggestion is generated. In order to assess how well the envisioned design fulfils the requirements, it is sometimes necessary to build a computer model of it for the analysis. The overall motivation of the work presented is to reduce the time spent on creating the model by reusing knowledge gained from developing similar products by suggesting, building and evaluating IT-systems. To verify the systems real design examples, obtained from companies that have participated in the research projects have been used. The work is based on two major application examples. The first, involving the automated geometrical idealisation of die-cast parts (Paper I-III), and the second involving manufacturability of powder metallurgy pressed and sintered parts (Paper IV-VI). The work starts from the point in the product development process where it exists a design suggestion represented as an arbitrary format CAD-model. In the powder metallurgy case the object is to secure that the geometry is suitable for the production process. In the die-casting case the object is to automatically create an idealised version of the model for shell elements meshing. These two tasks have previously been treated as two separate cases, addressed by completely different software. This thesis suggests a common method for addressing the two cases. The method is based on converting the CAD-models, using the geometrical restrictions of the production processes, into a format with a specialised feature structure, parameterisation and construction history using a feature recognition approach. The features are then automatically reconstructed in a target CAD-system. The resulting, specialised CAD-model can be used for automated design and design evaluation purposes, demonstrated in the thesis. The models are therefore called DAR (Design Automation Ready)-models. The DAR-models are useful in that they separate the conversion from the subsequent treatment of the models providing modularisation, flexibility and user insight in the model structure. In that a construction history and parameterisation have be constructed in the target CAD-system, the advanced geometry manipulation and means for knowledge management often provided in modern CAD-systems can be accessed in a transparent and user manageable way. This extends the usefulness of the CAD-systems from involving only interactive work to managing all components sharing the same production process.Teknologie Doktorsexamen
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Zetzsche, Torsten. "Rechnerunterstützung des Entwurfsprozesses durch funktional-technische Objektmodellierung." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2000. http://nbn-resolving.de/urn:nbn:de:swb:14-995273639437-63330.
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Thema der Arbeit ist die Konzeption, Entwicklung und Einführung in die Anwendung eines Entwurfssystems, das die Leistungsfähigkeit der derzeit während des Entwurfsprozesses angewandten Programme durch neue Funktionen erweitert. Die implementierte integrative Schnittstellenlösung fasst die bisher genutzten Applikationen zu einem Gesamtsystem zusammen. Der bidirektionale Datenaustausch zwischen allen integrierten Modulen verhindert zur Zeit noch notwendige Mehrfacheingaben identischer Daten. Die für die Modellierung eingesetzten CAD-Systeme bieten für die rechnerinterne Abbildung der Geometrie von Bauteilen eine hohe Funktionalität. Ungenügend ist aber die Erstellung der Funktionsstruktur mit rechentechnischen Hilfsmitteln gelöst. Dieses führt zum Entwurf neuer Produkte nahezu ohne den Einsatz der Informationstechnik und zur anschließenden Anfertigung der CAD-Modelle und Zeichnungen, wenn die Bauteile bereits in ihrer Grundstruktur bestimmt sind. Auch die Vorteile der parametrischen 3D-Modellierung, die für die Beschreibung der bauteilinternen Abhängigkeiten anwendbar ist, werden nur begrenzt genutzt. Gründe dafür liegen in der komplizierten Definition eineindeutig bestimmter Modelle und im ungenügend gelösten Datenaustausch mit externen Applikationen. Während die Ergebnisse einer Konstruktion als rechnerinterne Geometriemodelle detailliert vorliegen, werden die Daten der zugrunde liegenden Funktionsstruktur nicht oder nur zum geringen Teil erfasst. Wichtige Informationen über den Entstehungsprozess sind somit nach Abschluss einer Konstruktion nicht mehr verfügbar. Aufgrund dessen muss die gleichwertige Modellierung von Funktions- und Wirkstruktur sowie der Geometrie realisiert werden. Mit dem beschriebenen Entwurfssystem werden diese Strukturen erstellt und in einem komplexen Modell gespeichert. Im Rahmen folgender Konstruktionen kann dann nicht nur auf die Geometriedaten, sondern auch auf die Beziehungen, auf denen die Bauteilstruktur basiert, zugegriffen werden.
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Ding, Lian. "Feature technology and its applications in computer integrated manufacturing." Thesis, University of Bedfordshire, 2003. http://hdl.handle.net/10547/622150.
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Computer aided design and manufacturing (CAD/CAM) has been a focal research area for the manufacturing industry. Genuine CAD/CAM integration is necessary to make products of higher quality with lower cost and shorter lead times. Although CAD and CAM have been extensively used in industry, effective CAD/CAM integration has not been implemented. The major obstacles of CAD/CAM integration are the representation of design and process knowledge and the adaptive ability of computer aided process planning (CAPP). This research is aimed to develop a feature-based CAD/CAM integration methodology. Artificial intelligent techniques such as neural networks, heuristic algorithms, genetic algorithms and fuzzy logics are used to tackle problems. The activities considered include: 1) Component design based on a number of standard feature classes with validity check. A feature classification for machining application is defined adopting ISO 10303-STEP AP224 from a multi-viewpoint of design and manufacture. 2) Search of interacting features and identification of features relationships. A heuristic algorithm has been proposed in order to resolve interacting features. The algorithm analyses the interacting entity between each feature pair, making the process simpler and more efficient. 3) Recognition of new features formed by interacting features. A novel neural network-based technique for feature recognition has been designed, which solves the problems of ambiguity and overlaps. 4) Production of a feature based model for the component. 5) Generation of a suitable process plan covering selection of machining operations, grouping of machining operations and process sequencing. A hybrid feature-based CAPP has been developed using neural network, genetic algorithm and fuzzy evaluating techniques.
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Mamani, Gabriel Efrain Humpire. "Seleção supervisionada de características por ranking para processar consultas por similaridade em imagens médicas." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-20022013-095418/.
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Obter uma representação sucinta e representativa de imagens médicas é um desafio que tem sido perseguido por pesquisadores da área de processamento de imagens médicas com o propósito de apoiar o diagnóstico auxiliado por computador (Computer Aided Diagnosis - CAD). Os sistemas CAD utilizam algoritmos de extração de características para representar imagens, assim, diferentes extratores podem ser avaliados. No entanto, as imagens médicas contêm estruturas internas que são importantes para a identificação de tecidos, órgãos, malformações ou doenças. É usual que um grande número de características sejam extraídas das imagens, porém esse fato que poderia ser benéfico, pode na realidade prejudicar o processo de indexação e recuperação das imagens com problemas como a maldição da dimensionalidade. Assim, precisa-se selecionar as características mais relevantes para tornar o processo mais eficiente e eficaz. Esse trabalho desenvolveu o método de seleção supervisionada de características FSCoMS (Feature Selection based on Compactness Measure from Scatterplots) para obter o ranking das características, contemplando assim, o que é necessário para o tipo de imagens médicas sob análise. Dessa forma, produziu-se vetores de características mais enxutos e eficientes para responder consultas por similaridade. Adicionalmente, foi desenvolvido o extrator de características k-Gabor que extrai características por níveis de cinza, ressaltando estruturas internas das imagens médicas. Os experimentos realizados foram feitos com quatro bases de imagens médicas do mundo real, onde o k-Gabor sobressai pelo desempenho na recuperação por similaridade de imagens médicas, enquanto o FSCoMS reduz a redundância das características para obter um vetor de características menor do que os métodos de seleção de características convencionais e ainda com um maior desempenho em recuperação de imagensObtaining a representative and succinct description of medical images is a challenge that has been pursued by researchers in the area of medical image processing to support Computer-Aided Diagnosis (CAD). CAD systems use feature extraction algorithms to represent images. Thus, different extractors can be evaluated. However, medical images contain important internal structures that allow identifying tissues, organs, deformations and diseases. It is usual that a large number of features are extracted the images. Nevertheless, what appears to be beneficial actually impairs the process of indexing and retrieval of images, revealing problems such as the curse of dimensionality. Thus, it is necessary to select the most relevant features to make the process more efficient and effective. This dissertation developed a supervised feature selection method called FSCoMS (Feature Selection based on Compactness Measure from Scatterplots) in order to obtain a ranking of features, suitable for medical image analysis. Our method FSCoMS had generated shorter and efficient feature vectors to answer similarity queries. Additionally, the k-Gabor feature extractor was developed, which extracts features by gray levels, highlighting internal structures of medical images. The experiments performed were performed on four real world medical datasets. Results have shown that the k-Gabor boosts the retrieval performance, whereas the FSCoMS reduces the subsets redundancy to produce a more compact feature vector than the conventional feature selection methods and even with a higher performance in image retrieval
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Barton, Andrew Barton. "Integrating Manufacturing Issues into Structural Optimization." University of Sydney. Aerospace, Mechanical and Mechatronic, 2002. http://hdl.handle.net/2123/857.
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This dissertation aims to advance the field of structural optimization by creating and demonstrating new methodologies for the explicit inclusion of manufacturing issues. The case of composite aerospace structures was a main focus of this work as that field provides some of the greatest complexities in manufacturing yet also provides the greatest incentives to optimize structural performance. Firstly, the possibilities for modifying existing FEA based structural optimization methods to better capture manufacturing constraints are investigated. Examples of brick-based topology optimization, shell-based topology optimization, parametric sizing optimization and manufacturing process optimization are given. From these examples, a number of fundamental limitations to these methods were observed and are discussed. The key limitation that was uncovered related to a dichotomy between analytical methods (such as FEA) and CAD-type methods. Based on these observations, a new Knowledge-Based framework for structural optimization was suggested whereby manufacturing issues are integrally linked to the more conventional structural issues. A prototype system to implement this new framework was developed and is discussed. Finally, the validity of the framework was demonstrated by application to a generic composite rib design problem.
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Taiber, Joachim Gisbert. "Entwurf eines feature- und constraint-basierten CAD/CAM-Systems zur fertigungstechnischen Optimierung /." Zürich, 1996. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=11429.
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Arumugam, Jaikumar. "Analysis of feature interactions and generation of feature precedence network for automated process planning." Ohio : Ohio University, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1176142843.
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Lef, Annette. "CAD-Based Pose Estimation - Algorithm Investigation." Thesis, Linköpings universitet, Datorseende, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-157776.
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One fundamental task in robotics is random bin-picking, where it is important to be able to detect an object in a bin and estimate its pose to plan the motion of a robotic arm. For this purpose, this thesis work aimed to investigate and evaluate algorithms for 6D pose estimation when the object was given by a CAD model. The scene was given by a point cloud illustrating a partial 3D view of the bin with multiple instances of the object. Two algorithms were thus implemented and evaluated. The first algorithm was an approach based on Point Pair Features, and the second was Fast Global Registration. For evaluation, four different CAD models were used to create synthetic data with ground truth annotations. It was concluded that the Point Pair Feature approach provided a robust localization of objects and can be used for bin-picking. The algorithm appears to be able to handle different types of objects, however, with small limitations when the object has flat surfaces and weak texture or many similar details. The disadvantage with the algorithm was the execution time. Fast Global Registration, on the other hand, did not provide a robust localization of objects and is thus not a good solution for bin-picking.
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Gharib, Islam. "Integration of sketch-based ideation and 3D modeling with CAD systems." Thesis, Brunel University, 2013. http://bura.brunel.ac.uk/handle/2438/7436.
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This thesis is concerned with the study of how sketch-based systems can be improved to enhance idea generation process in conceptual design stage. It is also concerned with achieving a kind of integration between sketch-based systems and CAD systems to complete the digitization of the design process as sketching phase is still not integrated with other phases due to the different nature of it and the incomplete digitization of sketching phase itself. Previous studies identified three main related issues: sketching process, sketch-based modeling, and the integration between the digitized design phases. Here, the thesis is motivated from the desire to improve sketch-based modeling to support idea generation process but unlike previous studies that only focused on the technical or drawing part of sketching, this thesis attempts to concentrate more on the mental part of the sketching process which play a key role in developing ideas in design. Another motivation of this thesis is to produce a kind of integration between sketch-based systems and CAD systems to enable 3D models produced by sketching to be edited in detailed design stage. As such, there are two main contributions have been addressed in this thesis. The first contribution is the presenting of a new approach in designing sketch-based systems that enable more support for idea generation by separating thinking and developing ideas from the 3D modeling process. This kind of separation allows designers to think freely and concentrate more on their ideas rather than 3D modeling. the second contribution is achieving a kind of integration between gesture-based systems and CAD systems by using an IGES file in exchanging data between systems and a new method to organize data within the file in an order that make it more understood by feature recognition embedded in commercial CAD systems.
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Weber, Martins Thiago [Verfasser]. "Knowledge-based Feature Recognition for CAD Model Generation of Bifurcated Sheet Metal Parts / Thiago Weber Martins." Düren : Shaker, 2020. http://d-nb.info/1206855703/34.
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Gutiérrez, Rubert Santiago Carlos. "Análisis y procesado tecnológico del modelo sólido de una pieza para determinar sus elementos característicos de mecanizado." Doctoral thesis, Universitat Politècnica de València, 2008. http://hdl.handle.net/10251/1963.
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Una de las primeras etapas en la Planificación de Procesos asistida por ordenador, para procesos de mecanizado por arranque de material, consiste en identificar las zonas de material a eliminar en el bruto de partida para generar la pieza. El resultado es un conjunto de entidades llamadas: Elementos Característicos de Mecanizado, que tienen una clara relación con las operaciones de mecanizado.
Al procedimiento de obtención automática de estas entidades se le denomina: reconocimiento automático de Elementos Característicos de Mecanizado (AFR, Automatic Feature Recognition), en el que partiendo del modelo 3D del bruto y de la pieza se establecen las entidades de trabajo adecuadas (Elementos Característicos de Mecanizado). Estas entidades contienen la información necesaria para poder llevar a cabo una Planificación de Procesos automática. A su vez, la información se va completando y ampliando a medida que se avanza en las etapas de la Planificación.
En la Tesis se plantea el reconocimiento automático de Elementos Característicos de Mecanizado como una de las primeras etapas de la Planificación de Procesos, y que permite el enlace con el diseño asistido por ordenador. Este reconocimiento debe tener un planteamiento dinámico, ofreciendo distintas opciones. Su solución no debe ser una entrada estática, prefijada, para el resto de etapas de la Planificación. El proceso de reconocimiento está fuertemente influenciado por conceptos y decisiones de índole tecnológico (tipos de herramientas, movimientos característicos de los procesos, influencia del corte vinculado, ), que lo guían y que permiten obtener resultados válidos en la aplicación destino: el mecanizado.
Atendiendo a este planteamiento, la Tesis ofrece una solución general y completa al proceso de reconocimiento automático de Elementos Característicos de Mecanizado, teniendo en cuenta a los llamados procesos convencionales (torneado, fresado, limado, rectificado, etc.). La solución propuesta no se restringe a piezasGutiérrez Rubert, SC. (2007). Análisis y procesado tecnológico del modelo sólido de una pieza para determinar sus elementos característicos de mecanizado [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/1963
Palancia
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Tanizawa, Kiminobu. "HRCT features of interstitial lung disease in dermatomyositis with anti-CADM-140 antibody." Kyoto University, 2012. http://hdl.handle.net/2433/157463.
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Nassrallah, Wissam. "Store-Operated Response in CA1 Pyramidal Neurons Exhibits Features of Homeostatic Synaptic Plasticity." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33357.
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Homeostatic synaptic plasticity (HSP) regulates synaptic strength in response to changing neuronal firing patterns. This form of plasticity is defined by neurons’ ability to sense and over time integrate their level of firing activity, and to actively maintain it within a defined range. For instance, a compensatory increase in synaptic strength occurs when neuronal activity is chronically attenuated. However, the underpinning cellular mechanisms of this fundamental neural process remain poorly understood. We previously found that during activity deprivation, HSP leads to an increase in α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA) receptor function as well as a shift in subunit composition from Ca2+-impermeable GluA2-containing AMPA receptors to Ca2+-permeable GluA2-lacking AMPA receptors not only at synapses, but also at extrasynaptic sites. Neurons therefore appear to be actively enhancing Ca2+ entry, possibly as a compensatory mechanism in response to a prolonged Ca2+ deficit. To test whether the homeostatic response may, at least in part, be mediated by internal Ca2+ stores, we depleted endoplasmic reticulum (ER) Ca2+ stores by using the Sarco/endoplasmic reticulum Ca2+ ATPases (SERCA) pump blocker cyclopiazonic acid (CPA) for a prolonged period. Interestingly, we have found that prolonged Ca2+-store depletion leads not only to an increase in synaptic strength per se, but also a cell-wide increase in synaptic Ca2+-permeable GluA2-lacking AMPARs. This increase in Ca2+ influx following periods of inactivity is conceptually highly reminiscent of a store-operated response, whereby cells re-establish their calcium levels following Ca2+ store depletion using cell surface Ca2+ channels. Our results suggest that neurons use synaptic receptors as means to regulate store Ca2+ levels, thus significantly expanding our understanding of the repertoire used by neurons to modulate cellular excitability.
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Tennety, Chandu. "Machining Feature Recognition Using 2D Data of Extruded Operations in Solid Models." Ohio University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1181406949.
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McMillan, Matthew Christopher. "Editing the independent, digital feature film, mosaic." Queensland University of Technology, 2007. http://eprints.qut.edu.au/16558/.
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The production of the independent, digital feature film titled Mosaic was performed on a very low budget. The design and implementation of the post-production of the film required consideration of budgetary constraints, and solutions to these constraints that would still allow the creative freedom of the editor and the director. The technical design was based around digital filmmaking technology. The choice of this technology influenced how the editor was able to address aesthetic and technical challenges.
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Al-Osta, Husam E. I. "Detection of breast cancer microcalcifications in digitized mammograms : developing segmentation and classification techniques for the processing of MIAS database mammograms based on the wavelet decomposition transform and support vector machines." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4429.
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Mammography is used to aid early detection and diagnosis systems. It takes an x-ray image of the breast and can provide a second opinion for radiologists. The earlier detection is made, the better treatment works. Digital mammograms are dealt with by Computer Aided Diagnosis (CAD) systems that can detect and analyze abnormalities in a mammogram. The purpose of this study is to investigate how to categories cropped regions of interest (ROI) from digital mammogram images into two classes; normal and abnormal regions (which contain microcalcifications). The work proposed in this thesis is divided into three stages to provide a concept system for classification between normal and abnormal cases. The first stage is the Segmentation Process, which applies thresholding filters to separate the abnormal objects (foreground) from the breast tissue (background). Moreover, this study has been carried out on mammogram images and mainly on cropped ROI images from different sizes that represent individual microcalcification and ROI that represent a cluster of microcalcifications. The second stage in this thesis is feature extraction. This stage makes use of the segmented ROI images to extract characteristic features that would help in identifying regions of interest. The wavelet transform has been utilized for this process as it provides a variety of features that could be examined in future studies. The third and final stage is classification, where machine learning is applied to be able to distinguish between normal ROI images and ROI images that may contain microcalcifications. The result indicated was that by combining wavelet transform and SVM we can distinguish between regions with normal breast tissue and regions that include microcalcifications.
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Yao, Suqin. "Computer-Aided Manufacturing Planning (CAMP)of Mass Customization for Non-rotational Part Production." Link to electronic dissertation, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-1216103-153523/.
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Dissertation (Ph.D.) -- Worcester Polytechnic Institute.Keywords: Computer aided manufacturing planning; Object-oriented systems analysis (OSA); Feature; manufacturing resource capability; setup planning; multi-part fixture Includes bibliographical references (p.146-154).
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France, Grace. "Features of NMDA receptor-dependent LTP and LTD in the CA1 area of P14 and adult rat hippocampal slices." Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681550.
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N_methyl-O-aspartate receptors (NMOARs) play a pivotal role in synaptic plasticity in the CA1 region of the hippocampus and NMOAR abnormalities have been implicated in many neuropathological diseases and pathophysiologies. Whilst some forms of longterm potentiation (LTP) and long-term depression (LTD) have long been known to have an NMOAR dependence, the involvement of specific NMOAR subunits in LTP and LTD, especially under development, is still a controversial topic. The aim of this study was to clarify the role of the different NMOAR subunits in L TP and L TO, and to investigate the change in kinase activity involved in L TP induction during development. Furthermore, the effects of a newly synthesised phenanthrene derivative and NMOAR potentiator UBP709 were examined on synaptic plasticity at the CA3-CA 1 synapse. In two-week-old animals LTP induction (100 pulses, 100 Hz) was shown to be NMOAR dependent; however, no dominance of a single subunit was discovered. In contrast, LTD was also NMOAR dependent but required activation of GluN2B containing NMOARs in P14 rats. Kinase activity, which is involved in high frequency stimulation induced LTP, was demonstrated to change with age. A multi kinase pathway exists in P14 rats, but this is downregulated and LTP induction becomes CaMKl1 dependent in adult rats. A transient potentiation lasting approximately thirty minutes, known as short-term potentiation (STP), precedes L TP and is also NMOAR-dependent. Induction of STP is dependent on GluN2B- and GluN20-containing NMOARs as STP decays faster in the presence of Ro 25-6981, a GluN2B preferring antagonist, or UBP145, a GluN20 preferring antagonist. NVP, a GluN2A preferring antagonist, had no effect on STP. The novel NMOAR allosteric potentiator, UBP709, enhanced LTO induced by LFS (1 Hz, 900 pulses) and permitted induction of L TO using a 10Hz paradigm that did not induce L TO under control conditions in slices from P14 slices. In adult and aged rats L TO is not readily induced by LFS. However, application of UBP709 permitted induction of a robust L TO in slices from both adult and aged rats. This effect was shown to be NMOARdependent and, in adult rats, required activation of the GluN2B subunit. In summary, results have shown that CaMKl1 appears to dominate LTP in adulthood with the exception of PKA that is involved in STP, induction of which is dependent on GluN2B/20 subunits. Induction of L TP does not depend on a particular NMOAR-subunit whereas induction of L TO is strictly GluN2B dependent, irrespective of the developmental stage of the preparation. UBP709 appears to be a useful tool to investigate synaptic plasticity, which might 'prove beneficial for targeted development of GluN2B selective modulators.
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Turci, Alice. "Analisi di immagini del tessuto prostatico in Risonanza Magnetica multiparametrica." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
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INTRODUZIONE. In campo oncologico la Risonanza Magnetica multiparametrica (RMmp) sta diventando sempre più importante in quanto sequenze multiple, quali T2 e DWI, permettono di rilevare la presenza di tumore, ovvero di zone ipo-iper-intense rispetto al tessuto circostante. L’analisi delle immagini mediante tecniche di texture analysis può essere utilizzata per cercare dei potenziali biomarker che aiutino il radiologo nella diagnosi svolgendo un ruolo di second opinion per detection e diagnosis di una lesione ancor prima di aver eseguito la biopsia. MATERIALI E METODI. In questa Tesi sono state analizzate le sequenze T2 e DWI di RMmp-3T per identificare le neoplasie prostatiche mediante tecniche di texture analysis con estrazione di feature su patch locali centrate sui pixel d’interesse, la cui distribuzione spaziale è stata visualizzata ed analizzata mediante colormap su cui è stato applicato un algoritmo di segmentazione automatica. Sono state calcolate sette feature e per ciascuna nove descrittori statistici. RISULTATI. Dalla feature più significativa (entropia) nel caratterizzare l’eterogeneità del tessuto, sono state rilevate automaticamente le lesioni e confrontate con quelle segmentate manualmente dal medico, valutando mutualmente le performance ottenute (lesioni rilevate nel 96.55% dei casi con una media del 72.42% di lesioni con il radiologo come ground-truth e con una media del 53.33% di lesioni viceversa). Le feature locali risultano inoltre ben correlate con i biomarker clinici per la stratificazione delle lesioni (ρ=0.695 tra Skewness della Media e PSALT e ρ=0.790 tra la Kurtosi della Mediana e PSALT). CONCLUSIONI. I risultati ottenuti incoraggiano futuri approfondimenti nello studio della texture analysis che deve comprendere un’analisi multiparametrica di tutte le feature ed essere estesa a tutte le sequenze disponibili dalla RMmp. La metodologia sviluppata ha le caratteristiche per embrionali di un sistema di Computer Aided Detection/Diagnosis (CAD).
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Cai, Jing [Verfasser]. "Development of a Reference Feature-based Machining Process Planning Data Model for Web-enabled Exchange in Extended Enterprise / Jing Cai." Aachen : Shaker, 2007. http://d-nb.info/116650929X/34.
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