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Automating endoscopic camera motion for teleoperated minimally invasive surgery using inverse reinforcement learningAgrawal, Ankur S 13 December 2018 (has links)
During a laparoscopic surgery, an endoscopic camera is used to provide visual feedback of the surgery to the surgeon and is controlled by a skilled assisting surgeon or a nurse. However, in robot-assisted teleoperated systems such as the daVinci surgical system, the same control lies with the operating surgeons. This results in an added task of constantly changing view point of the endoscope which can be disruptive and also increase the cognitive load on the surgeons. The work presented in this thesis aims to provide an approach that results in an intelligent camera control for such systems using machine learning algorithms. A particular task of pick and place was selected to demonstrate this approach. To add a layer of intelligence to the endoscope, the task was classified into subtasks representing the intent of the user. Neural networks with long short term memory cells (LSTMs) were trained to classify the motion of the instruments in the subtasks and a policy was calculated for each subtask using inverse reinforcement learning (IRL). Since current surgical robots do not enable the movement of the camera and instruments simultaneously, an expert data set was unavailable that could be used to train the models. Hence, a user study was conducted in which the participants were asked to complete the task of picking and placing a ring on a peg in a 3-D immersive simulation environment created using CHAI libraries. A virtual reality headset, Oculus Rift, was used during the study to track the head movements of the users to obtain their view points while they performed the task. This was considered to be expert data and was used to train the algorithm to automate the endoscope motion. A 71.3% accuracy was obtained for the classification of the task into 4 subtasks and the inverse reinforcement learning resulted in an automated trajectory of the endoscope which was 94.7% similar to the human trajectories collected demonstrating that the approach provided in thesis can be used to automate endoscopic motion similar to a skilled assisting surgeon.
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Taktilitet i Virtual Reality, vän eller fiende? : En kvalitativ studie om sambandet mellan visuella stimuli och taktila stimuli i Virtual RealityLjungdahl, Petter January 2019 (has links)
I denna studie undersöks sambandet mellan visuella och taktila stimuli i Virtual Reality med avstamp i frågeställningarna: Hur stor roll spelar sambandet mellan visuella stimuli och taktila stimuli i en Virtual Reality-installation? Hur förändras deltagarens inlevelsekänsla när detta samband ändras? Hur förändras deltagarens rumsuppfattning när detta samband ändras? För att besvara frågeställningarna skapades två olika versioner av en interaktiv VR-installation utefter metoden forskning genom design. En av versionerna hade korrekt samband mellan visuella stimuli och taktila stimuli, det vill säga att deltagaren fysiskt kunde röra vid det denne såg med hjälp av fysiska objekt som var placerade i samma rum som installationen upplevdes i. Den andra versionen hade felaktigt samband mellan visuella stimuli och taktila stimuli, vilket innebar att de fysiska objekten hade flyttats en aning i Virtual Reality-installationen så att de ej speglade objekten i verkligheten. Det vill säga att informationen deltagaren avläste vid beröring ej stämde överens med informationen deltagaren avläste med synen. Därefter fick fyra deltagare testa dessa installationer och svara på frågor i en öppen intervjuform. Resultatet kopplades tydligt till Csíkszentmihályis flow-teori; när sambandet mellan dessa stimuli ej var korrekt så förändrades deltagarnas rumsuppfattning vilket bidrog till att de kände en lägre inlevelsekänsla. Möjligheten att kunna vidröra de fysiska objekten i sig ansågs dock som mer inlevelserikt än ifall möjligheten ej funnits där. Det ses även som styrkan med denna studie; att resultatet tydligt speglade de valda teorierna. Svagheten med studien var att resultatet enbart grundas på data från intervjuer med fyra deltagare, då flera ej hanns med inom tidsramen för studien.
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A rela????o da realidade virtual e os idosos: uma revis??o sistem??ticaBrito, Hana Barros Bezerra L??bo de 01 December 2017 (has links)
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Previous issue date: 2017-12-01 / The improvement of the quality of life, healthier habits on health and information the elderly population is constantly growing. The aging process is due to several changes in the body, and some of these changes can lead to physiological deficits in the body, and maintaining these healthy living habits are essential for longevity such as: food, lifestyle and physical activities. Virtual Reality is a method that is being evaluated by science, working with strands such as balance, mobility, cognition and functionality are being applied in the elderly population and are well received as methods of treatment or prevention. With the objective of reviewing the literature in the last 5 years, it brings to the reader, what was used of methodology, which statistical tests, such as receptivity of the elderly and levels of efficacy. Articles were searched in the Embase databases; Pubmed; Lalics and BDTD, at first 163 studies were selected, but only 9 studies remained for final analysis. The results indicate that Virtual Reality is an effective, and has a greater adherence to treatment than with some other methods, when evaluating statistical tests, the studies presented pointed out some shortcomings that should be taken into account. It is suggested that there is a deeper understanding of the subject in different lines of research; statistical planning should be better planned and methodologies replicated with a greater number of older people with clearer treatment protocols such as number of sessions, intervention time and times per week. / Devido a melhora da qualidade de vida, h??bitos mais saud??veis acesso a sa??de e informa????o a popula????o idosa est?? em constante crescimento. O processo de envelhecimento se dar por v??rias altera????es no corpo, e algumas dessas altera????es podem levar a d??ficits fisiol??gicos no organismo, e a manuten????o desses h??bitos de vida sald??vel s??o imprescind??veis para longevidade como: alimenta????o, estilo de vida e atividades f??sicas. A Realidade Virtual ?? um m??todo que est?? sendo avaliado pela ci??ncia, trabalhando com vertentes como equil??brio, mobilidade, cogni????o e funcionalidade est??o sendo aplicados na popula????o idoso e sendo bem recebidos como m??todos de tratamento ou preven????o. Com o objetivo de revisar a literatura nos ??ltimos 5 anos, traz ao leitor, o que foi utilizado de metodologia, quais os testes estat??sticos, como foi a receptividade dos idosos e os n??veis de efic??cia. Foram pesquisados artigos nas bases de dados Embase; Pubmed; Lalics e BDTD, A primeiro momento163 estudos foram selecionados, por??m s?? restavam para analise final 9 estudos. Os resultados apontam que a Realidade Virtual ?? um eficaz, e possui maior ades??o ao tratamento do que com alguns outros m??todos, ao avaliar os testes estat??sticos, os estudos apresentados apontaram algumas faltas que devem ser levadas em considera????o. Sugere-se que haja um maior aprofundamento sobre o assunto em diferentes linhas de pesquisa; os planejamentos estat??sticos devem ser melhor planejados e a metodologias sejam replicadas com maior n??mero de idosos, com protocolos de tratamentos mais claros, como n??mero de sess??es, tempo de interven????o e vezes por semana.
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Realidade virtual aplicada à ergonomia por meio do design participativo /Gasperini, Ricardo. January 2010 (has links)
Orientador: José Carlos Plácido da Silva / Banca: João Alberto Camarotto / Banca: Luis Carlos Paschoarelli / Resumo: A ergonomia está cada vez mais presente no desenvolvimento do produto e consequentemente no processo produtivo. As empresas estão sentindo que o investimento em ergonomia é de suma importância na preservação da saúde de seus colaboradores como também no aumento de eficiência da produtividade. Para isso algumas empresas investem em alta tecnologia como Centros de Realidades Virtuais para simular e prever atividades futuras e desenvolver novos produtos. Esta ferramenta utilizada pelas indústrias busca antecipar a melhor solução para os postos de trabalho tornando as atividades menos desgastantes e penosas como também tornando os produtos mais eficientes. Deste modo a pesquisa teve como objetivo avaliar a aplicação da realidade virtual imersiva na análise e avaliação ergonômica por meio do design participativo e assim conhecer suas potencialidades. Este estudo buscou verificar até que ponto a realidade virtual pode auxiliar os especialistas em ergonomia sem que os mesmos tenham que produzir modelos físicos. A metodologia empregada nesta pesquisa envolveu a utilização de um Centro de Realidade Virtual - CRV com o método de grupo de foco simulando atividades e captando a percepção dos sujeitos envolvidos. O experimento evidenciou grande relevância nas aplicações da realidade virtual em algumas situações como na análise de biomecânica, movimento simultâneo e percepção do usuário, porém em algumas atividades verificou-se a necessidade da construção de modelos físicos para maior interação e envolvimento do sujeito. Os testes efetuados também mostraram que a realidade virtual tornou possível a avaliação ergonômica de uma atividade que seria impossível de ser efetuada em ambiente real sem que houvesse uma grande alocação financeira. Este fato se deve pelo motivo da dimensão do produto estudado (grande proporção) e a complexidade do processo ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The ergonomics is even more present time in the development of the productive process. The companies feel that the investment in ergonomics is of utmost importance in the preservation of its collaborators health as well as in the increase of efficiency of the productivity. For this reason companies invest in high technology as Centers of Virtual Realities to simulate and to foresee future activities as well as to develop new products. This tool used by the industries searches to anticipate the best solution for the work place turning tough activities less tiring as well as making the products more efficient. In this way the research had as objective to evaluate the application of the immersed virtual reality in the analysis and ergonomic evaluation through the participatory design to know its potentialities. This study aimed verifies to what point the virtual reality can assist the specialists in ergonomics without producing physical models. The methodology used in this research involved the use of a Center of Virtual Reality - CVR with the method of group of focus simulationg some activities and catching the perception of the involved person. The experiment evidenced great relevance in the applications of the virtual reality in some situations as in the analysis of biomechanics and perception of the user, however in some activities it was verified the necessity of the construction of physical models for bigger interaction and involvement of the participants. The tests had also shown that the virtual reality became the ergonomic evaluation of an activity possible which would be impossible to be done in real environment without the necessity on financial allocation. This fact is due to the reason of the dimension of the studied product (great ratio) and the complexity of the process. The tool (Virtual Reality) also provided to try the involvement of the team through participatory design ... (Complete abstract click electronic access below) / Mestre
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A utilização da arquitetura CORBA na construção de ambientes virtuais distribuídos. / The use of CORBA architecture in the construction of distributed virtual environments.Sementille, Antonio Carlos 17 September 1999 (has links)
As aplicações de Realidade Virtual imergem o usuário em um ambiente virtual simulado, denominado Ambiente Virtual. A simulação de Ambientes Virtuais é um processo intensivo, o qual pode ser drasticamente limitado se for restrito a apenas um computador. É possível, através da distribuição, aumentar-se o tamanho e a abrangência destes sistemas, permitindo que múltiplos usuários interajam entre si e com o ambiente. Estes ambientes virtuais são conhecidos como Ambientes Virtuais Distribuídos. A construção de Ambientes Virtuais Distribuídos é uma tarefa complexa, principalmente quando são levados em consideração, aspectos como a estruturação da comunicação ao nível de processo, a escalabilidade, a interoperabilidade e o reuso de seus componentes. Tais aspectos são, também, enfatizados, através da Tecnologia de Objetos Distribuídos, cujo maior representante atual é a Arquitetura CORBA (Common Object Kequest Broker Architecture). Assim, neste contexto, este trabalho apresenta um estudo e uma metodologia para a construção de Ambientes Virtuais Distribuídos que utilizem a Arquitetura CORBA como infra-estrutura de alto nível para a comunicação e sincronização entre seus objetos. Buscou-se, também, apresentar os elementos teóricos e práticos desta abordagem, através da implantação de três protótipos, os quais formaram uma base comparativa para o estudo da viabilidade das idéias usadas. / Virtual Reality applications immerge the user in a simulated virtual environment entitled Virtual Environment that is an intensive process which can be drastically limited if restricted to a single computer. It is possible to enlarge the size and reach of these systems through distribution to allow multiple users to Interact among themselves and with the environment. These virtual environments are known as Distributed Virtual Environments. Their construction is a complex task, mainly when aspects such as communication structuring at the process level, scalability, interoperability and reuse of their components are taken into consideration. Such aspects are also emphasized through Distributed Objects Technology, being CORBA (Common Object Request Broker Architecture) currently the biggest representative. Thus, in this context, this thesis presents a study and methodology for the construction of Distributed Virtual Environments which utilize CORBA architecture as a high-level structure for the communication and synchronization among their objects. Last but not least, the aim of this thesis was also to present theoretical and practical elements of this approach, by implementing three prototypes, which formed a comparative basis to study the viability of the ideas hereby used.
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Approche topologique de la métrologie du mouvement pour des applications en réalité virtuelle / Topological approach of movement metrology for virtual reality applicationsBensekka, Chakib 15 October 2018 (has links)
Dans le domaine médical, une meilleure connaissance de la fonctionmotrice est susceptible de permettre d’établir des thérapies adaptéesà chaque lésion motrice et des outils d’études et de dépistage dansle cas de maladies neurodégénératives. Dans le domaine de la réalitévirtuelle, la reconnaissance du mouvement est un point angulaire dansl’interaction de l’avatar ou de la personne en immersion avec sonenvironnement. Plusieurs travaux ont été menés dans le but de proposerdes approches de classification du mouvement humain. L’idée principalede ces méthodes est d’extraire des invariants des données enregistréesafin de les regrouper en clusters. Cependant, l'étude du mouvementhumain avec des systèmes de capture de mouvement génère une quantitéde données volumineuse, avec des relations non linéaires entre elles.Les méthodes présentées dans la littérature scientifique utilisent cesdonnées soit directement comme entrée à des algorithmes declassification, soit en appliquant une méthode de réductiondimensionnelle, comme l’analyse en composantes principales avant laclassification. Ces méthodes restent extrêmement sensibles au bruitblanc pendant l'enregistrement ainsi qu’aux différences morphologiquesentre les sujets. Dans notre travail, nous allons présenter uneméthodologie de classification et de reconnaissance du mouvementhumain, qui se base sur l’analyse topologique des donnéescinématiques. L’analyse topologique sera réalisée via la persistancehomologique, qui est une méthode d’analyse des données volumineusesqui permet de leur associer une signature topologique. On combineracette méthode d’analyse topologique avec des algorithmesd’apprentissage afin d’augmenter la précision de la reconnaissance desmouvements en réduisant l'impact des différences morphologiques entreles sujets ainsi que l’impact du bruit blanc issu pendant l'étaped’acquisition du mouvement. Par ailleurs, on combinera la méthoded’analyse topologique avec un algorithme de réseaux de neuronestemporels, afin de construire une approche qui permet de prédire lasuite d’un mouvement à partir d’une partie d’un intervalled’enregistrement.Les résultats ont montré la capacité de l’approche proposée à obtenirune précision avec un taux élevé lors de la classification, ainsi quesa robustesse face au bruit blanc et aux différences morphologiquesentre les personnes. Les résultats ont montré aussi le cout élevé entemps de calcul de notre approche. Nous avons proposé des méthodes(algorithme et parallélisme) de façon à réduire les temps de calculs. / In the medical field, a better knowledge of the motor function isimportant for us to determine therapies adapted to each motor lesion andtools of studies and screening for neurodegenerative diseases. In thedomain of virtual reality, motion recognition is an issue in theinteraction of the avatar or the user in immersion with theirenvironment.Several studies have been conducted with the aim of proposingapproaches to the classification of human movement. The main idea ofthese methods is to extract invariants from the recorded data in orderto order them into clusters. However, the study of human motion withmotion capture systems generates a big quantity of data with nonlinearrelations between them. The presented methods in the scientificliterature use these data either directly as input to classificationalgorithms or by applying a dimensional reduction method such asprincipal component analysis prior to classification. These methodsremain extremely sensitive to white noise during recording as well asmorphological differences between subjects.In our work, we will present a methodology of classification andrecognition of human movement which is based on the topologicalanalysis of kinematic data. Topological analysis will be performed viahomological persistence which is a large data analysis method thatallows them to be topologically signed. This method of topologicalanalysis will be combined with learning algorithms to increase theaccuracy of motion recognition by reducing the impact of morphologicaldifferences between subjects, as well as the impact of white noiseissued during the step of movement acquisition. Also, we will combinethe topological analysis method with a temporal neural networkalgorithm in order to build an approach that allows to predict thecontinuation of a movement from a part of a recording interval.The results showed the ability of the proposed approach to achievehigh accuracy at classification, as well as its robustness againstwhite noise and morphological differences between subjects. Theresults also showed the high cost in computing time of our approachwhich we tried to reduce by modifying its steps and by rewriting thecode so that it can be executed in parallel.
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Realistic haptic modeling & rendering of touch-enabled virtual environments. / CUHK electronic theses & dissertations collectionJanuary 2006 (has links)
In comparison with other methods assuming that multi-contacts between tool and object are point or line based contacts, our body-based haptic interaction model involves the intrinsic contacts with different tool/object materials acquired from the real world for the realistic haptic simulation. Our studies in interactive haptic deformations is to marry the merits of traditional deformable modeling techniques in computer graphics with force-enabled deformations guided by real-world physics laws, simulating the realistic tangible sensation of interactive haptic manipulation with user-specified constraints in touch-enabled virtual environments. The multi-resolution rendering framework developed in our system unifies the graphics/haptics rendering processes based on the construction of hierarchical imposter representations of surface and volumetric models, and the optimal haptic-scene performance at run time is employed to meet both the visual and haptic perceptual qualities. The proposed work is extensible to support users perceptually experience the virtual objects with different materials through the tangible interfaces in the augmented virtual worlds. In general, haptic perception and manipulation can be further constructed uniformly in the multi-resolution rendering framework. The future work includes investigating multiple force evaluation methods and haptic contact models and in addition integrating them into the unified haptic-scene framework, for the rich and dexterous experiences in large, touch-enable virtual environments. / The body-based haptic interaction model is proposed and developed for simulating the contacted forces between the haptic tools and interacting object, based on Hertz's theory establishing the intrinsic stress distribution related to real material properties. In comparison with the common force evaluation models, the proposed body-based haptic interaction model involves the intrinsic contacts with different tool/object materials acquired from the real world for the realistic haptics simulation. For adding the haptic sensations with touch-enabled soft objects, the thesis first studies multiple force-reflecting deformable objects in volume sculpting, then soft object deformation of Loop subdivision surfaces, and further the soft object freeform deformation through mass-spring Bezier volume lattice. The constrained haptic deformations based on the metaballs are experimented to effectively control the interactive force distribution within the influence range, making the deformable simulation of objects easy to control and manipulate. Lastly, the unified multi-resolution rendering framework of touch-enabled virtual environments is proposed and developed, with level-of-detail imposter representations of both graphics and haptics perceptions. The hierarchical graphics/haptics imposter descriptions of hybrid models (e.g. surfaces/volumes) within the virtual environment are constructed in advance, to maximize the optimal performance of the rendering processes during the interactive haptic-scene navigation and explorations. / This thesis dissertation is mainly devoted to investigate the realistic haptics techniques in touch-enabled virtual environments. It has three major parts: the body-based haptic interaction model to simulate the realistic, physical tool-object interactions based on Hertz's contact theory and applications; the realization of interactive haptic manipulation of deformable objects with volume/surface representations, and further development of constrained haptic deformations based on the metaballs; the integration of multi-resolution rendering framework with level-of-detail impostor representations of graphics and haptics objects, to support the optimal rendering performance during the interactive navigation of touch-enabled virtual environments. / Virtual Reality (VR) applications strive to simulate real or imaginary scenes with which users can interact and perceive the effects of their actions in real time. Adding haptic information such as vibration, tactile array, force feedback simulation enhances the sense of presence in virtual environments. Realistic haptic modeling & rendering is the core component in feeling and manipulating virtual objects within the virtual environments. Haptics interfaces present new challenges in data processing analysis, physical modeling, interactive visualization and tangible simulations, especially in the situation where it is crucial for the operators to touch, grasp and manipulate rigid/soft objects in the virtual worlds. / Chen Hui. / "April 2006." / Adviser: Hanqiu Sun. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6498. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 177-185). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
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Resource optimization and dynamic state management in a collaborative virtual environment.January 2001 (has links)
Yim-Pan Chui. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 126-132). / Abstracts in English and Chinese. / Abstract --- p.ii / Acknowledgments --- p.v / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Introduction to Collaborative Virtual Environments --- p.1 / Chapter 1.2 --- Barriers to Resource Management and Optimization --- p.3 / Chapter 1.3 --- Thesis Contributions --- p.5 / Chapter 1.4 --- Application of this Research Work --- p.6 / Chapter 1.5 --- Thesis Organization --- p.6 / Chapter 2 --- Resource Optimization - Intelligent Server Partitioning --- p.9 / Chapter 2.1 --- Introduction --- p.9 / Chapter 2.2 --- Server Partitioning --- p.13 / Chapter 2.2.1 --- Related Works --- p.15 / Chapter 2.2.2 --- Global Optimization Approaches --- p.17 / Chapter 2.3 --- Hybrid Genetic Algorithm Paradigm --- p.17 / Chapter 2.3.1 --- Drawbacks of traditional GA --- p.18 / Chapter 2.3.2 --- Problem Modeling --- p.19 / Chapter 2.3.3 --- Discussion --- p.24 / Chapter 2.4 --- Results --- p.25 / Chapter 2.5 --- Concluding Remarks --- p.28 / Chapter 3 --- Dynamic State Management - Dead Reckoning of Attitude --- p.32 / Chapter 3.1 --- Introduction to Dynamic State Management --- p.32 / Chapter 3.2 --- The Dead Reckoning Approach --- p.35 / Chapter 3.3 --- Attitude Dead Reckoning by Quaternion --- p.37 / Chapter 3.3.1 --- Modeling of the Paradigm --- p.38 / Chapter 3.3.2 --- Prediction Step --- p.39 / Chapter 3.3.3 --- Convergence Step --- p.40 / Chapter 3.3.4 --- Overall Algorithm --- p.46 / Chapter 3.4 --- Results --- p.47 / Chapter 3.5 --- Conclusion --- p.51 / Chapter 4 --- Polynomial Attitude Extrapolation --- p.52 / Chapter 4.1 --- Introduction --- p.52 / Chapter 4.2 --- Related Works on Kalman Filtering --- p.53 / Chapter 4.3 --- Historical Propagation of Quaternion --- p.54 / Chapter 4.3.1 --- Cumulative Extrapolation --- p.54 / Chapter 4.3.2 --- Method I. Vandemonde Approach --- p.55 / Chapter 4.3.3 --- Method II. Lagrangian Approach --- p.58 / Chapter 4.4 --- History-Based Attitude Management --- p.60 / Chapter 4.4.1 --- Multi-order Prediction --- p.60 / Chapter 4.4.2 --- Adaptive Attitude Convergence --- p.63 / Chapter 4.4.3 --- Overall Algorithm --- p.67 / Chapter 4.5 --- Results --- p.69 / Chapter 4.6 --- Conclusion --- p.77 / Chapter 5 --- Forward Difference Approach on State Estimation --- p.78 / Chapter 5.1 --- Introduction --- p.78 / Chapter 5.2 --- Positional Forward Differencing --- p.79 / Chapter 5.3 --- Forward Difference on Quaternion Space --- p.80 / Chapter 5.3.1 --- Attitude Forward Differencing --- p.83 / Chapter 5.3.2 --- Trajectory Blending --- p.84 / Chapter 5.4 --- State Estimation --- p.86 / Chapter 5.5 --- Computational Efficiency --- p.87 / Chapter 5.6 --- Results --- p.88 / Chapter 5.7 --- Conclusion --- p.96 / Chapter 6 --- Predictive Multibody Kinematics --- p.98 / Chapter 6.1 --- Introduction --- p.98 / Chapter 6.2 --- Dynamic Management of Multibody System --- p.100 / Chapter 6.2.1 --- Multibody Representation --- p.100 / Chapter 6.2.2 --- Paradigm Overview --- p.101 / Chapter 6.3 --- Motion Estimation by Joint Extrapolation --- p.102 / Chapter 6.3.1 --- Individual Joint Extrapolation --- p.102 / Chapter 6.3.2 --- Forward Propagation of Joint State --- p.104 / Chapter 6.3.3 --- Pose Correction --- p.107 / Chapter 6.4 --- Limitations on Predictive Articulated State Management --- p.108 / Chapter 6.5 --- Implementation and Results --- p.109 / Chapter 6.6 --- Conclusion --- p.112 / Chapter 7 --- Complete System Architecture --- p.113 / Chapter 7.1 --- Server Cluster Model --- p.113 / Chapter 7.1.1 --- Peer-Server Systems --- p.114 / Chapter 7.1.2 --- Server Hierarchies --- p.114 / Chapter 7.2 --- Multi-Level Resource Management --- p.115 / Chapter 7.3 --- Aggregation of State Updates --- p.116 / Chapter 7.4 --- Implementation Issues --- p.117 / Chapter 7.4.1 --- Medical Visualization --- p.117 / Chapter 7.4.2 --- Virtual Walkthrough Application --- p.118 / Chapter 7.5 --- Conclusion --- p.119 / Chapter 8 --- Conclusions and Future directions --- p.121 / Chapter 8.1 --- Conclusion --- p.121 / Chapter 8.2 --- Future Research Directions --- p.122 / Chapter A --- Quaternion Basis --- p.124 / Chapter A.1 --- Basic Quaternion Mathematics --- p.124 / Chapter A.2 --- The Exponential and Logarithmic Maps --- p.125 / Bibliography --- p.126
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Proposta de ferramenta para desenvolvimento de simuladores interativos para treinamento. / A proposal for tools to interactive training simulation development.Ferraz, Rodrigo Barroca Dias 19 July 2010 (has links)
Simulações man-in-the-loop, ou human-in-the-loop reproduzem virtualmente ambientes reais ou imaginários para o usuário, sendo aplicadas em diversas áreas como, entretenimento, treinamento, experimento e reabilitação. Na área de treinamento, os simuladores são cada vez mais empregados visando principalmente a redução de custos e riscos, além do controle total das condições do treinamento. Simuladores de treinamento têm sido utilizados em diversas áreas, como medicina (simuladores de procedimentos cirúrgicos), aviação, trânsito, náutica, industrial, militar, entre outras. Uma das dificuldades no desenvolvimento de simuladores para treinamento é projetar e implementar o modelo do ambiente virtual em software. Apesar de existirem diversas ferramentas (livres ou comerciais) que podem auxiliar no desenvolvimento dos simuladores, poucas se propõem à modelagem do sistema e sua execução, e estas são, em sua maioria, proprietárias. O principal objetivo deste trabalho é conceber uma ferramenta genérica para auxiliar na modelagem, estruturação e implementação de simuladores de ambientes virtuais voltados para treinamento, partindo da proposta de uma arquitetura de software baseada na decomposição estrutural do sistema a ser simulado. A utilização de uma ferramenta genérica tem a finalidade de reduzir o tempo e o custo de desenvolvimento de simuladores de treinamento, facilitando a integração simultânea de diversas equipes de trabalho e a reutilização de componentes de softwares para outras aplicações. Foi concebida uma arquitetura de software baseada nos trabalhos da literatura e desenvolvido um protótipo da ferramenta genérica. Para avaliar a ferramenta foi realizado um estudo de caso baseado no software de um simulador de aeronave de asas rotativas, modelo Bell Jet Ranger III e nos procedimentos operacionais reais. O estudo foi realizado por meio da adaptação parcial do software do simulador original utilizando a ferramenta proposta. Os resultados obtidos mostraram a viabilidade da utilização da arquitetura e da ferramenta genérica para o desenvolvimento de simuladores de treinamento. / Man-in-the-loop or human-in-the-loop simulations reproduce virtually real or imaginary environments to the user, being used for several purposes, such as, entertainment, training, experiment and rehabilitation. In training area, the simulators are more and more used aiming, specially for costs and risks reduction besides the total control of training conditions. Training simulators have been used in several areas such as medicine (surgical procedures simulators), evaluation, traffic, nautical, industrial, military, among others. One of the difficulties in the simulator development for training is to project and implement the virtual environment model in software. Even though there are several free and commercial tools that might help in simulator development, few of them focus on system modeling and execution, and those are, in it\'s majority, proprietary. The main purpose of this work is to design a generic tool to assist the modeling, structuring and implementation of virtual environment simulators for training, starting from the proposal of a software architecture based on the structural decomposition of the system to be simulated. The use of a generic tool aims to reduce time and cost of developing training simulators, facilitating simultaneous integration of various workgroups and reuse of software components for other applications. Initially, a software architecture for training simulators was designed based on academic researches and a prototype of a generic tool was developed. To evaluate this tool, a case study was conducted based on the Bell Jet Ranger III rotorcraft simulator software and real operational procedures. The study was performed by partially adapting the original simulator software using the proposed tool. The results showed the feasibility of using the purposed architecture and generic tool for training simulators development.
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Desenvolvimento de um ambiente para simulação da manufatura baseado em features e realidade virtual / Development of environment for simulation of manufacturing based on features and virtual realityHeráclito Lopes Jaguaribe Pontes 10 October 2012 (has links)
Atualmente, com a diversificação dos produtos demandados, os sistemas de manufatura têm se tornado cada vez mais complexos e de difícil operacionalização. Dificilmente o responsável pela manufatura tem toda a informação necessária para antever os detalhes necessários à sua execução. Por outro lado, as empresas não dispõem de tempo nem de recursos para testar alternativas de manufatura no sistema real. Com isso, a simulação baseada nas features, ou seja, na geometria da peça, se torna importante, pois retrata fielmente as características do produto a ser manufaturado, facilitando a gestão da manufatura. Esse trabalho foi estruturado a partir da revisão da literatura sobre os conceitos de sistemas de manufatura, tecnologia de features, simulação, realidade virtual e modelos de processos de software. O objetivo do trabalho foi desenvolver um ambiente a partir de uma nova abordagem para simulação da manufatura baseado nas features das peças com uma interface tridimensional baseada em realidade virtual. A partir dessas simulações, o usuário poderá tomar decisões baseadas em indicadores como: tempo total de manufatura, custo e tempo por recurso de fabricação e movimentação, tempo de espera em fila e taxa de utilização de cada recurso num sistema de manufatura específico sem alterar o cotidiano da empresa. O desenvolvimento do sistema foi executado dentro do paradigma da orientação a objetos e foi dividido em etapas: análise de requisitos, projeto, implementação, verificação e validação e documentação. Para mostrar que as funcionalidades do ambiente de simulação decorrentes da abordagem proposta no trabalho são aplicáveis em sistemas de manufatura reais foram propostas duas aplicações com suas soluções. / Nowadays with the diversification of products demanded, manufacturing systems have become increasingly complex and with difficult operation. Hardly the person responsible for the manufacturing area has all the information necessary to anticipate the details for their implementation. On the other hand, companies don\'t have the time or resources to test alternatives in the real manufacturing system. With this simulation based on the features, i.e., the part geometry becomes important because it represents faithfully the characteristics of the product being manufactured, making it easy the management of manufacturing. This work was structured from the literature review on the concepts of manufacturing systems, features technology simulation, virtual reality and software process models. The objective of this study was to develop an environment from a new approach for simulation of manufacturing based on features of the parts with a three-dimensional interface based on virtual reality. From these simulations, the user can make decisions based on indicators such as: total time manufacturing, costs and time for manufacturing and resource handling, time of queuing and rate of utilization resource in a manufacturing system without changing the daily life of the company. The development of the system was implemented within the paradigm of object orientation and was divided into steps: requiriments analysis, project, implementation, verification and validation and documentation. To show that the functions of the simulation environment due the approach proposed in this work are applicable to real manufacture systems have been proposed two applications with their solutions.
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