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1
Islam, Md Ashraful. „IMPLEMENTATION OF VIRTUAL SYNCHRONOUS GENERATOR METHODOLOGIES FOR RENEWABLE INTEGRATION“. Master's thesis, Temple University Libraries, 2017. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/482193.
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Electrical EngineeringM.S.E.E.
In conventional centralized power systems, power is generated mostly by large synchronous generators (SGs), where the frequency of the grid depends on the rotational frequency of the prime mover. If there are any sudden changes in the load, the rotor inertia property restrains the changes in frequency and keeps the system stable. During transient periods, rotor kinetic energy of the rotor is injected into the grid to balance power supply between generation and load. With the recent high penetration of renewable energy sources (RES), the power grid is undergoing structural changes with an increased inverter-based distributed generation. Since inverter based power sources do not have inertia as conventional synchronous machines (SM), high penetration of inverters may cause instability and sharp voltage fluctuations in the grid. If inverter based power sources could be configured as regular SM by introducing virtual inertia and damping property, many of the problems, such as frequency regulation, islanded operation, and parallel operation of inverter-based DGs will be resolved. This thesis investigates mathematical modeling and control of VSG’s to emulate the inertia and damping property of SMs. Simulation results are presented on the modeling and closed-loop performance of VSGs for an island microgrid.
Temple University--Theses
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Paquette, Andrew Donald. „Power quality and inverter-generator interactions in microgrids“. Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51803.
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This research addresses some of the difficulties faced when operating voltage controlled inverters with synchronous generators in microgrids. First, an overview of microgrid value propositions is provided, and the problems faced when attempting to use microgrids to provide improved power quality are discussed. Design considerations for different types of microgrids are provided to enable microgrids to deliver the desired functionality without adding unnecessary cost. The main body of this research investigates the poor transient load sharing encountered between voltage controlled inverters and synchronous generators in islanded operation. Poor transient load sharing results in high peak inverter rating requirements and high cost. The tradeoff between power quality and power sharing is highlighted, and methods to improve transient load sharing are proposed. The use of current limiting to protect inverters during faults and overloads is also investigated. Stability problems are identified when using simple inverter current limiting methods when operating in parallel with synchronous generators. Virtual impedance current limiting is proposed to improve transient stability during current limiting. The methods proposed in this thesis for mitigating inverter overloads and faults will allow for more reliable and cost effective application of inverter based distributed energy resources with synchronous generators in microgrids.
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Runzi, Zhang. „Virtual-Channel Based Wormhole NoC on FPGA for ForSyDe/NoC System Generator Tool Suite“. Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-230624.
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Nowadays, the number of processors integrated on system-on-chip (SoC) increases rapidly and makes multiprocessor system-on-chip design (MPSoC) a regular feature of the embedded system. [25] To support the communication between several homogeneous or heterogeneous processors a communication infrastructure, Networkon-Chip (NoC) technology was raised more than ten years ago. Decades of research provides the NoC area with an increasingly sophisticated knowledge system. A wide variety of NoC systems are developed and evaluated. To simplify the design flow of NoC systems, a NoC System Generator Tool (NGS) [23] [25] [26] is developed by researchers of Royal Institute of Technology. It aims to generate NoC systems with different topology, size, processing elements, and network protocols on FPGAs. NoC routers are central parts in modelling NoC communications. In the current version, Nostrum router is used as only supported communication backbone. This project starts from an analysis to NoC theory and steps into important aspects related to NoC router design to implement a register transfer level (RTL) synthesizable wormhole (WH) router in VHDL for NGS tool. WH router is a comparatively old however widely used NoC router structure. A Virtual-Channel (VC) based flow control is adopted in this design to improve the performance. After implementing the WH router, functional tests on a single router, 2×2 and 3×3 WH Router based network are performed on Modelsim 10.0. VHDL test benches with “textio” operations are prepared to generate a clear report to reveal packets’ transfer details in the network. The router and 2×2 network is synthesized on Quartus II for the Cyclone IV E FPGA family to compare the area overhead with Nostrum NoC.
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Kyle, Stephen Christopher. „Applications of information sharing for code generation in process virtual machines“. Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25446.
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As the backbone of many computing environments today, it is important that process virtual machines be both performant and robust in mobile, personal desktop, and enterprise applications. This thesis focusses on code generation within these virtual machines, particularly addressing situations where redundant work is being performed. The goal is to exploit information sharing in order to improve the performance and robustness of virtual machines that are accelerated by native code generation. First, the thesis investigates the potential to share generated code between multiple threads in a dynamic binary translator used to perform instruction set simulation. This is done through a code generation design that allows native code to be executed by any simulated core and adding a mechanism to share native code regions between threads. This is shown to improve the average performance of multi-threaded benchmarks by 1.4x when simulating 128 cores on a quad-core host machine. Secondly, the ahead-of-time code generation system used for executing Android applications is improved through the use of profiling. The thesis investigates the potential for profiles produced by individual users of applications to be shared and merged together to produce a generic profile that still provides a lot of benefit for a new user who is then able to skip the expensive profiling phase. These profiles can not only be used for selective compilation to reduce code-size and installation time, but can also be used for focussed optimisation on vital code regions of an application in order to improve overall performance. With selective compilation applied to a set of popular Android applications, code-size can be reduced by 49.9% on average, while installation time can be reduced by 31.8%, with only an average 8.5% increase in the amount of sequential runtime required to execute the collected profiles. The thesis also shows that, among the tested users, the use of a crowd-sourced and merged profile does not significantly affect their estimated performance loss from selective compilation (0.90x-0.92x) in comparison to when they they perform selective compilation with their own unique profile (0.93x). Furthermore, by proposing a new, more powerful code generator for Android’s virtual machine, these same profiles can be used to perform focussed optimisation, which preliminary results show to increase runtime performance across a set of common Android benchmarks by 1.46x-10.83x. Finally, in such a situation where a new code generator is being added to a virtual machine, it is also important to test the code generator for correctness and robustness. The methods of execution of a virtual machine, such as interpreters and code generators, must share a set of semantics about how programs must be executed, and this can be exploited in order to improve testing. This is done through the application of domain-aware binary fuzzing and differential testing within Android’s virtual machine. The thesis highlights a series of actual code generation and verification bugs that were found in Android’s virtual machine using this testing methodology, as well as comparing the proposed approach to other state-of-the-art fuzzing techniques.
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Novosád, Boris. „Simulační modelování elektromagnetického vibračního generátoru“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228738.
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The aim of this work is to create complex virtual model of electromagnetic vibration generator. This model will include mechanical and electromagnetic subsystem and also the model of output circuit. Created model will be implemented in Matlab/Simulink enviroment and model parameters will be identified so that the compare of simulation and real results will be acceptable.
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Marques, Felipe de Souza. „Technology mapping for virtual libraries based on cells with minimal transistor stacks“. reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2008. http://hdl.handle.net/10183/16130.
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Atualmente, as tecnologias disponíveis para a fabricação de dispositivos eletrônicos permitem um alto grau de integração de semicondutores. Entretanto, esta integração torna o projeto, a verificação e o teste de circuitos integrados mais difíceis. Normalmente, o projeto de circuitos integrados é consideravelmente afetado com a diminuição do tamanho dos dispositivos eletrônicos em tecnologias sub-micrônicas. Conseqüentemente, os projetistas adotam metodologias rígidas para produzir circuitos de alta qualidade em tempo razoável. Ferramentas de auxílio ao projeto de circuitos eletrônicos são utilizadas para automatizar algumas das etapas do projeto, ajudando o projetista a encontrar boas soluções rapidamente. Uma das tarefas mais difíceis no projeto de circuitos integrados é fazer com que o circuito respeite as restrições de atraso. Isto depende de várias etapas do processo de síntese. Em metodologias baseadas em bibliotecas de células, isto está diretamente relacionado ao algoritmo para mapeamento tecnológico e as células disponíveis na biblioteca. O atraso de cada célula depende do tamanho dos transistores e da topologia da rede de transistores. Isso determina as características de atraso, potência e área de uma célula. O mapeamento tecnológico define as principais características estruturais do circuito, principalmente em área, potência e atraso. A qualidade do circuito mapeado depende das células disponíveis na biblioteca de células. Este trabalho propõe um novo método para mapeamento com bibliotecas virtuais para redução de atraso em circuitos combinacionais. Ambos os algoritmos baseiam-se em uma topologia de células capaz de implementar funções Booleanas com cadeias mínimas de transistores em série. Os algoritmos reduzem o número de transistores em série do caminho mais longo do circuito, considerando que cada célula é implementada por uma rede de transistores que obedecem um número máximo de transistores em série. O número de transistores em série é calculado de forma Booleana, garantindo que este seja o número mínimo necessário para implementar a função lógica da célula. Os algoritmos estão integrados a um gerador de células que utiliza tal topologia e realiza o dimensionamento dos transistores. Ganhos significativos podem ser obtidos combinando estas duas técnicas em uma ferramenta para mapeamento tecnológico.Currently, microelectronic technologies enable high degrees of semiconductor integration. However, this integration makes the design, verification, and test challenges more difficult. The circuit design is often the first area under assault by the effects of aggressive scaling in deep-submicron technologies. Therefore, designers have adopted strict methodologies to deal with the challenge of developing high quality designs on a reasonable time. Electronic Design Automation tools play an important role, automating some of the design phases and helping the designer to find a good solution faster. One of the hardest challenges of an integrated circuit design is to meet the timing requirements. It depends on several steps of the synthesis flow. In standard cell based flows, it is directly related to the technology mapping algorithm and the cells available in the library. The performance of a cell is directly related to the transistor sizing and the cell topology. It determines the timing, power and area characteristics of a cell. Technology mapping has a major impact on the structure of the circuit, and on its delay and area characteristics. The quality of the mapped circuit depends on the richness of the cell library. This thesis proposes two different approaches for library-free technology mapping aiming delay reduction in combinational circuits. Both algorithms rely on a cell topology able to implement Boolean functions using minimal transistors stacks. They reduce the overall number of serial transistors through the longest path, considering that each transistor network of a cell has to obey to a maximum admitted chain. The mapping algorithms are integrated to a cell generator that creates cells with minimal transistor stacks. This cell generator is also in charge of performing the transistor sizing. Significant gains can be obtained in delay due to both aspects combined into the proposed mapping tool.
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Bilík, Petr. „Virtuální měřicí přístroje pro podporu výuky“. Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442484.
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This diploma thesis deals with the creation of the Virtual Measuring Instruments web application. This tool mainly enables us to simulate the real measuring instruments widely used in the laboratories of FEEC BUT. It is intended to serve students for initial acquaintance with specific devices. The theoretical part is focused on the research into the web applications programming and suitable programming languages to implement the proposed application are selected. Furthermore, the specific virtualized devices are described. The result of the experimental part consists in creating a universal application interface to extend the proposed application with other devices. Finally, the specific tests of the developed platform are presented.
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Seshadri, Satyanarayanan. „Solid particle transport behavior and the effect of aerosol mass loading on performance of a slit virtual impactor“. Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/538.
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Transport of solid particles in a slit virtual impactor has been analyzed using visualization techniques. Particle trajectories were observed using laser-induced fluorescence of monodisperse particles seeded in the virtual impactor flow. It was observed from these trajectories that for smaller inertia particles essentially followed the flow streamlines, whereas higher inertia particles tend to deflect from their initial streamlines. These transport characteristics were used to determine particle collection efficiency curves, and the percentage of defect particle transmission, particles transmitted to the major flow that are well beyond the experimentally determined 50% cutoff. Defect percentages were found to be in good agreement with those based on a local stokes number approach, an analytical model using a converging flow velocity profile. It was hypothesized that these defects occur by virtue of larger particles passing through the near wall flow region and consequently transported to the major flow. The trajectories of such defect occurrences clearly show that these particles originated in the near wall region. Performance at higher mass loadings was evaluated using a background dust matrix generated by a turntable aerosol generator. At high mass loadings, clogging of the slit led to the deterioration of the impactor's performance. The time taken to clog the silt was estimated by modeling the slit edge as a single filter fiber of rectangular cross section with the primary mechanism of filtration being interception and was found to be in good agreement with the experimental data. Elimination of defect transmission and clogging would be possible by the provision of a sheath airflow, which ensures that the near wall regions are free of particles.
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Moulichon, Audrey. „Conception d'un système adaptatif dynamique de "générateur synchrone virtuel" pour la stabilisation des micro-réseaux électriques à fort taux de pénétration d'énergie renouvelable“. Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT064.
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Les sources classiques d'énergie distribuée (DER) fournissant de l'énergie aux microgrids (généralement des groupes électrogènes diesel) sont progressivement remplacées par les onduleurs basés sur des sources d'énergie renouvelables (RES). Cependant, l'intermittence des sources d'énergie renouvelables pose des problèmes de stabilité majeurs, en particulier dans le contexte des microgrids, notamment parce que ces sources diminuent l'inertie disponible du réseau. Par conséquent, les stratégies de contrôle traditionnelles pour les onduleurs, qui interfacent les différents DER connectés au microgrid, doivent être adaptées.Le générateur virtuel synchrone (VSG) est l’une des solutions les plus populaires pouvant participer à l’augmentation de l’inertie des microgrids et pouvant être intégré dans les études de stabilité traditionnelles car il présente des similitudes avec une machine synchrone. Le VSG étant encore un concept récent, principalement pris en compte pour l'intégration de la DER dans un microgrid, diverses problématiques demeurent non résolues (certaines d'entre elles sont abordées dans ce manuscrit). De plus, les différentes solutions trouvées dans la littérature ne prennent pas en compte les aspects industriels et pratiques de son développement (également pris en compte dans cette thèse industrielle).Cette thèse est dédiée aux onduleurs basés sur le VSG et à leur intégration dans des microgrids à forte pénétration d'énergie renouvelable variable. Cette thèse a été réalisée grâce à la coopération de deux laboratoires, G2Elab et Gipsa-Lab, en collaboration avec Schneider Electric et son équipe de R & D, Power ConversionThe classical distributed energy resources (DER) supplying energy to microgrids (usually diesel generator-sets) are progressively supplanted by supplier based on renewable energy sources (RES). However, the intermittency of RES leads to major stability issues, especially in the context of microgrids, notably because these sources usually decrease the available inertia of the grid. Hence, the traditional control strategies for inverters, interfacing the various DERs connected to the microgrid, needs adapting.The virtual synchronous generator (VSG) is one of the most popular solution that can participate in increasing the microgrids inertia and that could be integrated into traditional stability studies because it presents similarities with a synchronous machine. As the VSG is still a recent concept, mostly considered for the DER integration in microgrid, various problematics remain unresolved (some of which are addressed in this manuscript). In addition, the different solutions that can be found in the literature do not consider the industrial and practical aspect of its development (also considered in this industrial thesis).This thesis is dedicated to the VSG-based inverters and their integration in microgrids with a high level of variable renewable energy penetration. This PhD have been carried out thanks to the cooperation between two laboratories, G2Elab and Gipsa-Lab, in collaboration with Schneider Electric and its R&D team, Power Conversion
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Verhulst, Adrien. „Étude de Faisabilité d'Études Consommateurs d'Achat de Fruits et Légumes « Moches » dans un Supermarché Virtuel“. Thesis, Ecole centrale de Nantes, 2018. http://www.theses.fr/2018ECDN0016/document.
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La grande distribution affiche une politique anti-gaspillage et a ainsi proposé dès 2014des Fruits et Légumes (F&Ls) « moches » [109] à la vente. Mais ces ventes sont temporaires et locales,et ont des effets peu étudiés sur le comportement des consommateurs. Nous proposons ici d'étudier si un magasin virtuel immersif (dans lequel nous contrôlons les F&Ls) peut être utilisé pour étudier le comportement des consommateurs confronté à des F&Ls « moches ». Afin d'avoir assez de F&Ls pour remplir le magasin virtuel, nous avons généré des F&Ls d'apparences variables de manière semi-procédurale comme suit :(1) nous générons le maillage avec des Cylindres Généralisés (CGs) [6] ; puis (2) gêneront les couleurs avec un système de particule.Nous avons réalisé 2 études comparatives (resp.N=142 et N=196). L'une portant sur le comportement consommateur lorsque les F&Ls sont plus ou moins anormaux (8F&Ls séparés en 4 groupes : sans déformation,légèrement déformés, déformés et fortement déformés). Ces différences n'avaient pas d'incidences sur le comportement. L'autre portait sur le comportement consommateur lorsque l'environnement est plus ou moins immersif (8 F&Ls sans déformation et 8 F&Ls déformés, séparés en 3groupes : magasin laboratoire, magasin virtuel non immersif et magasin virtuel immersif). Il existe des différences entre ces environnements sur le comportement. Enfin, nous avons étudié si la représentation virtuelle du consommateur avait un effet lors de l'achat des produits (incluant, mais ne se limitant pas aux F&Ls) nous avons donc réalisé une étude (N=29) avec 2 groupes : avatar obèse et avatar non-obèse. Il existe des différences localisées entre ces représentations sur le comportement consommateurThe retail sector has an anti-waste policyand has therefore offered “ugly” FaVs (Fruits and Vegetables) for sale as early as 2014 [109]. But these sales remain temporary and local and have little studied effects on consumer behavior. We propose here to study if an immersive virtual store (in which we control the FaVs) can be used to study consumer behavior confronted to “ugly” FaVs To have enough “ugly” FaVs to fill the virtual store, we developed a method capable of generatings emiprocedural FaVs. To do so we: (1) generate the mesh with Generalized Cylinders (GCs) [6]; then (2) generate the colors with a particle system.We conducted 2 comparative studies (N=142 andN=196 respectively). The first study focused on consumer behavior when the FaVs are abnormal (8 FaVs separated into 4groups: no deformation, slightly deformed, deformed and strongly deformed). These differences had no impact on consumer behavior. The other study focused on consumer behavior when the environment is more or less immersive (8 FaVs without deformation and 8 FaVs with deformation, separated into 3 groups: laboratory store, non immersive virtual store and immersive virtual store).There are differences between these environments on consumer behavior. Finally, we studied if the virtual representation of the consumer had an impact during the purchase of products (including, but not limited to, FaVs). To do so we carried out a third consumer study (N=29) (2groups: obese avatar and non-obese avatar). There are very localized differences between these representations on consumer behavior
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Gylleus, Karl. „Perception of procedurally generated virtual buildings“. Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-229967.
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Due to the high amount of time it takes to manually design virtual buildings and cities it is often desired to automate the process. Procedural modeling is a way to achieve this by algorithmically generating buildings. By using inverse generation procedural descriptions of buildings can be extracted from a given model. When using a procedural generator to create a city some variance is needed during generation which might lead to unrealistic buildings if not handled correctly. This thesis investigates which features of buildings are most sensitive to change in regards to their realism. An inverse procedural modeler is implemented in C# using Unity, which can generate split grammar rules from input pictures of building facades and their defined layout. Generated rules can then be used to generate buildings. Photographs of facades on residential buildings are edited in Adobe Photoshop and fed to the implemented generator to recreate real buildings. These buildings and manually altered versions of them are used to carry out an experiment involving independent participants in order to find which features on facades detracts most from their realism when changed. The findings are that certain features impact a buildings realism more than others when changed. Color and window styles on a facade are especially sensitive. This knowledge can in the future be used to improve building generators such that they are careful in editing the window style and colors of created buildings.Med anledning av den långa tid det tar att manuellt skapa virtuella byggnader och städer är det ofta önskvärt att automatisera processen. Procedurell modellering är ett sätt att uppnå detta genom att algoritmiskt generera byggnader. Genom att använda inversprocedurell generering kan procedurella beskrivningar av byggnader extraheras från givna modeller. När en procedurell generator används för att skapa en stad krävs det varians i generationen vilket kan leda till orealistiska byggnader om det inte sköts korrekt. Denna avhandling undersöker vilka karaktäristiker på byggnader som är mest känsliga för att bli ändrade vad gäller deras realism. En inversprocedurell generator är skriven i C# och implementerad i Unity, som kan generera split grammar regler från givna bilder av fasader och dess definierade struktur. Fotografier av fasader från bostadshus redigeras i Adobe Photosop och matas till den implementerade generatorn för att återskapa riktiga byggnader. Dessa byggnader och manuellt ändrade versioner av dem används i ett experiment med oberoende deltagare för att undersöka vilka karaktäristiker som fråntar mest realism från byggnaderna när de ändras. De funna resultaten är att vissa element av byggnadsfasader påverkar byggnaders realism mer än andra. Färg och stil på fönster är i synnerhet känsliga för ändring. Denna kunskap kan i framtiden änvändas för att förbättra byggnadsgeneratorer sådant att de är försiktiga med att ändra just fönsterstil och färg på skapade byggnader.
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Long, Harry. „Procedurally generated realistic virtual rural worlds“. Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/20874.
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Manually creating virtual rural worlds is often a difficult and lengthy task for artists, as plant species selection, plant distributions and water networks must be deduced such that they realistically reflect the environment being modelled. As virtual worlds grow in size and complexity, climates vary on the terrain itself and a single ecosystem is no longer sufficient to realistically model all vegetation. Consequentially, the task is only becoming more difficult for these artists. Procedural methods are extensively used in computer graphics to partially or fully automate some tasks and take some of the burden off the user. Input parameters for these procedural algorithms are often unintuitive, however, and their impact on the final results, unclear. This thesis proposes, implements, and evaluates an approach to procedurally generate vegetation and water networks for realistic virtual rural worlds. Rather than placing these to reflect the environment being modelled, the work-flow is mirrored and the user models the environment directly by specifying the resources available. These intuitive input parameters are subsequently used to configure procedural algorithms and determine suitable vegetation, plant distributions and water networks. By design, the placeable plant species are configurable so any type of environment can be modelled at various levels of detail. The system has been tested by creating three ecosystems with little effort on the part of the user.
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Madden, Neil. „Collaborative narrative generation in persistent virtual environments“. Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/10802/.
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This thesis describes a multi-agent approach to generating narrative based on the activities of participants in large-scale persistent virtual environments, such as massivelymultiplayer online role-playing games (MMORPGs). These environments provide diverse interactive experiences for large numbers of simultaneous participants. Involving such participants in an overarching narrative experience has presented challenges due to the difficulty of incorporating the individual actions of so many participants into a single coherent storyline. Various approaches have been adopted in an attempt to solve this problem, such as guiding players to follow pre-designed storylines, or giving them goals to achieve that advance the storyline, or by having developers (‘dungeon masters’) adapt the narrative to the real-time actions of players. However these solutions can be inflexible, and/or fail to take player interaction into account, or do so only at the collective level, for groups of players. This thesis describes a different approach, in which embodied witness-narrator agents observe participants’ actions in a persistent virtual environment and generate narrative from reports of those actions. The generated narrative may be published to external audiences, e.g., via community websites, Internet chatrooms, or SMS text messages, or fed back into the environment in real-time to embellish and enhance the ongoing experience with new narrative elements derived from participants’ own achievements. The design and implementation of this framework is described in detail, and compared to related work. Results of evaluating the framework, both technically, and through a live study, are presented and discussed.
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GAO, YING. „VIRTUAL TERRAIN GENERATION AND GPU BASED RENDERING“. University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1148322986.
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Nakhal, Bilal. „Generation of communicative intentions for virtual agents in an intelligent virtual environment : application to virtual learning environment“. Thesis, Brest, 2017. http://www.theses.fr/2017BRES0156/document.
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La réalité virtuelle joue un rôle majeur dans le développement de nouvelles technologies de l’éducation, et permet de développer des environnements virtuels pour l’apprentissage, dans lesquels, des agents virtuels intelligents jouent le rôle de tuteur. Ces agents sont censés aider les utilisateurs humains à apprendre et appliquer des procédures ayant des objectifs d’apprentissage prédéfini dans différents domaines. Nous travaillons sur la construction d’un système temps-réel capable d’entamer une interaction naturelle avec un utilisateur dans un Environnement d’Apprentissage Virtuel (EAV). Afin d’implémenter ce modèle, nous proposons d’utiliser MASCARET (Multi-Agent System for Collaborative, Adaptive & Realistic Environments for Training) comme modèle d’Environnement Virtuel Intelligent (EVI) afin de représenter la base de connaissances des agents, et de modéliser la sémantique de l’environnement virtuel et des activités des utilisateurs. Afin de formaliser l’intention des agents, nous implémentons un module cognitif dans MASCARET inspiré par l’architecture BDI (Belief-Desire-Intention) qui nous permet de générer des intentions de haut-niveau pour les agents. Dans notre modèle, ces agents sont représentés par des Agents Conversationnels Animés (ACA), qui sont basés sur la plateforme SAIBA (Situation, Agent, Intention, Behavior, Animation). Les agents conversationnels de l’environnement ont des intentions communicatives qui sont transmises à l’utilisateur via des canaux de communication naturels, notamment les actes communicatifs et les comportements verbaux et non-verbaux. Afin d’évaluer notre modèle, nous l’implémentons dans un scénario pédagogique concret pour l’apprentissage des procédures d’analyse de sang dans un laboratoire biomédical. Nous utilisons cette application afin de réaliser une expérimentation et une étude pour valider les propositions de notre modèle. L’hypothèse de notre étude est de supposer que la présence d’un ACA dans un Environnement Virtuel (EV) améliore la performance du processus d’apprentissage (ou qu’au moins, ça ne le dégrade pas) dans le contexte de l’apprentissage d’une procédure spécifique. La performance de l’utilisateur est représentée par le temps requis pour l’exécution de la procédure, le nombre d’erreurs commises et le nombre de demande d’assistance. Nous analysons les résultats de cette évaluation, ce qui confirme partiellement l’hypothèse de l’expérience et affirme que la présence de l’ACA dans l’EV ne dégrade pas la performance de l’apprenant dans le contexte de l’apprentissage d’une procédureVirtual Reality plays a major role in developing new educational methodologies, and allows to develop virtual environments for learning where intelligent virtual agents play the role of tutors. These agents are expected to help human users to learn and apply domain-specific procedures with predefined learning outcomes. We work on building a real-time system able to sustain natural interaction with the user in a Virtual Learning Environment (VLE). To implement this model, we propose to use the Multi-Agent System for Collaborative, Adaptive & Realistic Environments for Training (MASCARET) as an Intelligent Virtual Environment (IVE) model that provides the knowledge base to the agents and model the semantic of the virtual environment and user’s activities. To formalize the intention of the agents, we implement a cognitive module within MASCARET inspired by BDI (Belief-Desire-Intention) architecture that permits us to generate high-level intentions for the agents. Furthermore, we integrate Embodied Conversational Agents (ECA), which are based on the SAIBA (Situation, Agent, Intention, Behavior, Animation) framework. The embodied agents of the environment have communicative intentions that are transmitted to the user through natural communication channels, namely the verbal and non-verbal communicative acts and behaviors of the ECAs. To evaluate our model, we implement it in a concrete pedagogical scenario for learning blood analysis procedures in a biomedical laboratory. We use this application to settle an experiment to validate the propositions of our model. The hypothesis of this experiment is to assume that the presence of anECA in a Virtual Environment (VE) enhances the learning performance (or at least does not degrade it) in the context of a learning procedure. The performance is represented by the time of execution, the number of committed errors and the number of requests for assistance. We analyze the results of this evaluation, which partially confirms the hypothesis of the experiment and assure that having an ECA in the VLE does not degrade the performance of the learner in the context of a learning procedure
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Stokes, Michael James. „Multimodal Behaviour Generation Frameworks in Virtual Heritage Applications : A Virtual Museum at Sverresborg“. Thesis, Norwegian University of Science and Technology, Department of Computer and Information Science, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9014.
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This masters thesis proposes that multimodal behaviour generation frameworks are an appropriate way to increase the believability of animated characters in virtual heritage applications. To investigate this proposal, an existing virtual museum guide application developed by the author is extended by integrating the Behavioural Markup Language (BML), and the open-source BML realiser SmartBody. The architectural and implementation decisions involved in this process are catalogued and discussed. The integration of BML and SmartBody results in a dramatic improvement in the quality of character animation in the application, as well as greater flexibility and extensibility, including the ability to create scripted sequences of behaviour for multiple characters in the virtual museum. The successful integration confirms that multimodal behaviour generation frameworks have a place in virtual heritage applications.
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Achenbach, Jascha [Verfasser]. „Generation of Virtual Humans for Virtual Reality, Medicine, and Domestic Assistance / Jascha Achenbach“. Bielefeld : Universitätsbibliothek Bielefeld, 2019. http://d-nb.info/1189813068/34.
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Newman, Guy. „Characterisation of virtual power plants“. Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/characterisation-of-virtual-power-plants(5e647750-5a44-40f0-8a33-763361d3a50b).html.
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The growing number of micro generation devices in the electrical network is leading many to consider that these devices can no longer be considered as fit and forget, but should instead be considered as having a demonstrable network impact which should be predicted and utilised. One of the techniques for considering the impacts of these devices is the Virtual Power Plant (VPP). The VPP is the aggregation of all the Distributed Generation (DG) connected into the network up to and including the connection voltage of the VPP, such that the cumulative power up the voltage levels can be seen in the single VPP unit, rather than across a broad spread of devices. One of the crucial tasks in characterising the VPP, developed in this work, is the ability to correctly predict and then aggregate the behaviour of several technology types which are weather driven, as a large proportion of DG is weather driven. Of this weather driven DG, some can only typically be dispatched with modification and the rest cannot be dispatched at all. The aggregation of the VPP as part of the electrical network is also developed, as the constraints of the network and the reliability of the network cannot be overlooked when considering the aggregation of the VPP. From a distribution network operator's (DNO) perspective, these characterisation models can be used to highlight problems in the network introduced by the addition of DG, but are also generally utilitarian in their role of predicting the power output (or negative load) found throughout the network due to DG. For a commercial agent interested in selling energy, these models allow for accurate predictions of energy to be determined for the trading period. A VPP agent would also be adversely affected by line failure in the network, leading to the development of an N-1 analysis based upon reliability rates of the network, which is used as the basis for a discussion on the impacts of single line failure and the mitigation available through feedback from the DNO.
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Trescak, Tomás. „Intelligent Generation and Control of Interactive Virtual Worlds“. Doctoral thesis, Universitat Autònoma de Barcelona, 2012. http://hdl.handle.net/10803/117675.
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Esta tesis aboga por el uso de los mundos virtuales como una tecnología de futuro en el dominio de
los mundos virtuales serios, en particular en aplicaciones e-‐* (e-‐learning, e-‐commerce, e-‐
government) y en simulaciones sociales. En estas aplicaciones, el entorno virtual 3D está poblado
por un gran número de habitantes que pueden ser humanos o avatares controlados por agentes
virtuales inteligentes que se involucran en interacciones complejas con su entorno y con los demás
participantes.
Un problema importante que impide la adopción generalizada de la tecnología de mundos virtuales
en estos dominios es que, en general, los mundos virtuales son difíciles de construir y se tiene que
emplear un gran esfuerzo en el diseño del entorno virtual 3D y en la programación de los agentes
virtuales; pero es aún más difícil asegurar la validez de las interacciones de forma que se prevengan
comportamientos no permitidos.
Para abordar este problema, hemos desarrollado una solución integral que automatiza el diseño de
estos mundos virtuales y de su población. Nuestro enfoque se basa en la utilización de las
instituciones virtuales, que son mundos virtuales que regulan las interacciones de sus participantes.
El enfoque principal de esta tesis está en explicar cómo los métodos existentes de especificación
formal de las instituciones virtuales se pueden extender para traducir automáticamente la
especificación institucional en un entorno interactivo 3D utilizando el enfoque de las gramáticas de
formas (Shape Grammars) y para poblar, de forma también automática, este tipo de entornos con
agentes virtuales.
Las gramáticas de formas son una técnica visual potente para la generación de diseños 2D y 3D,
pero el trabajo realizado hasta el momento en esta área no se adecua a las características de
nuestro problema. Por lo tanto, en esta tesis hemos extendido los trabajos realizados en este
campo y hemos desarrollado el framework “Shape Grammar Interpreter”, que se ocupa de las
limitaciones de las soluciones existentes. Hemos utilizado este framework para el desarrollo del
concepto de Virtual World Grammar, que es un subconjunto de las gramáticas de formas dirigido a
la generación automática de mundos virtuales normativos. Como resultado de esta tesis, la Virtual
World Grammar ha sido formalizada e implementada en un entorno de desarrollo que no sólo
permite la generación automática de mundos virtuales normativos, sino también su
implementación independiente de la plataforma (utilizando VIXEE, la infraestructura que se ha
desarrollado como una parte importante de esta tesis).
Otra contribución de esta tesis es el desarrollo de un mecanismo de generación automática de un
gran número de agentes de software. Estos agentes son capaces de realizar interacciones
inteligentes con objetos 3D dentro del entorno. Además, estos agentes son capaces de colaborar
con avatares controlados por humanos, facilitar la resolución de sus problemas y asegurar que
todas sus acciones se adhieren de forma estricta a las normas sociales de la institución.
Para ello, hemos desarrollado un modelo general de agente virtual que permite situar a un agente
en un mundo virtual normativo, generar sus propios objetivos en función de sus necesidades
fisiológicas y psicológicas, así como generar dinámicamente los planes para satisfacer estos
objetivos mediante la especificación institucional subyacente.
Para ilustrar la utilidad de los métodos y técnicas desarrolladas en esta tesis, hemos aplicado éstas
al campo de la simulación histórica, recreando la vida de la ciudad de Uruk. Hemos mostrado cómo
nuestro enfoque permite crear un gran número de agentes diversos tanto en aspectos visuales
como de comportamiento, así como la generación dinámica de los alimentos, herramientas y otros
elementos que se utilizan para satisfacer sus objetivos, mientras actúan de forma correcta,
históricamente hablando.This thesis advocates the use of non-‐gaming virtual worlds as a significant future technology for the domain of ``serious games’’ and in particular e-‐* applications (e-‐ learning, e-‐commerce, e-‐government) and social simulations. In such systems, a 3D virtual environment is populated by a large number of inhabitants that can be either human-‐ controlled avatars or intelligent virtual agents who engage in complex interactions with their virtual environment and other participants. One significant problem that impedes wide adoption of the virtual worlds technology for these problem domains is that virtual worlds in general are difficult to build, and significant effort has to be put into designing the 3D virtual environment and programming virtual agents; but it is even harder to ensure the validity of participant so that unauthorized behavior can be prevented. To address this problem, we have developed a comprehensive technological solution that automates the design of such virtual worlds and its population with virtual agents. Our approach is based on the utilization of virtual institutions, which are virtual worlds with normative regulation of participant interactions. The key focus of the thesis is on explaining how existing methods of formal specification of virtual institutions can be extended to automatically translate the institutional specification into an interactive 3D environment using the shape grammars approach and automatically populating such environments with virtual agents. Shape grammars represent a powerful visual technique for creating procedural 2D and 3D designs, but existing work was not immediately suitable for our problem. Thus, we have extended existing work and developed the Shape Grammar Interpreter framework, which addresses the limitations of existing solutions. This framework was further utilized for developing the concept of Virtual World Grammar, which is a sub-‐set of shape grammars targeting automatic generation of normative virtual worlds. As the result of this dissertation, Virtual Worlds Grammars constitute a strong formalization and a development environment not only enabling automatic generation of normative virtual worlds, but also their platform independent deployment (using the VIXEE infrastructure that has been developed as an important part of this dissertation). Another significant contribution of this thesis is developing a mechanism of automatic population of the generated environments with large numbers of software agents, which are capable of intelligent interactions with 3D objects placed in the environment. Moreover, these agents are able to collaborate with human-‐controlled avatars, facilitate their problem-‐solving and ensure that all their actions strictly adhere to social norms of the given institution. For this purpose, we have developed a general-‐purpose virtual agent model that enables an agent to be situated within any normative virtual world, generate its own goals based on its current physiological and psychological needs, as well as to dynamically generate plans for satisfying these goals using the underlying institutional specification. To illustrate the usefulness of the developed technology, we have applied it to the domain of historical simulation, where we show how virtual world grammars and automatically generated virtual agents can be used for re-‐enacting everyday life of ancient people in one of humanity's first cities, the city of Uruk. We showed how our approach allows to create a large number of visually and behaviorally diverse agents, as well as dynamically generating food, tools and other items that they can utilize to satisfy their goals, while acting in a historically correct way.
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Raghunathan, Rajiv. „Virtual qualification methodology for next-generation area-array packages“. Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/18849.
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Serbinski, Theodore Joseph. „Design of electronic experiments using computer generated virtual instruments“. Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/28109.
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Approved for public release; distribution unlimitedThe recent availability of low-cost computer controlled data acquisition systems have made it conceptually possible to replace much of the data recording and data analysis work associated with the classical electronics laboratory experiments required in a typical Electrical Engineering program. This thesis reports the results of a study focused on putting those concepts into practice. It is the first application of student laboratory Virtual Instruments at the school. Specifically, this thesis reports on the practicality of using a standard personal computer equipped with National Instruments LabVIEW for Windows and a data acquisition board to replace the typical manual instrumentation and data extraction required for seven Naval Postgraduate School ECE 2200 laboratory experiments. Appendices include the front panel display with associated block diagram code and the revised course laboratory experiments
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Nain, Delphine 1979. „An interactive virtual endoscopy tool with automotive path generation“. Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87240.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (leaves 106-109).
by Delphine Nain.
M.Eng.
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Fowler, Lee Everett. „A Virtual pilot algorithm for synthetic HUMS data generation“. Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54473.
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Regime recognition is an important tool used in creation of usage spectra and fatigue loads analysis. While a variety of regime recognition algorithms have been developed and deployed to date, verification and validation (V&V) of such algorithms is still a labor intensive process that is largely subjective. The current V&V process for regime recognition codes involves a comparison of scripted flight test data to regime recognition algorithm outputs. This is problematic because scripted flight test data is expensive to obtain, may not accurately match the maneuver script, and is often used to train the regime recognition algorithms and thus is not appropriate for V&V purposes. In this paper, a simulation-based virtual pilot algorithm is proposed as an alternative to physical testing for generating V&V flight test data. A “virtual pilot” is an algorithm that replicates a human’s piloting and guidance role in simulation by translating high level maneuver instructions into parameterized control laws. Each maneuver regime is associated with a feedback control law, and a control architecture is defined which provides for seamless transitions between maneuvers and allows for execution of an arbitrary maneuver script in simulation. The proposed algorithm does not require training data, iterative learning, or optimization, but rather utilizes a tuned model and feedback control laws defined for each maneuver. As a result, synthetic HUMS data may be generated and used in a highly automated regime recognition V&V process. In this thesis, the virtual pilot algorithm is formulated and the component feedback control laws and maneuver transition schemes are defined. Example synthetic HUMS data is generated using a simulation model of the SH-60B, and virtual pilot fidelity is demonstrated through both conformance to the ADS-33 standards for selected Mission Task Elements and comparison to actual HUMS data.
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Zeng, Xin. „Generation of a 3D virtual environment based on story descriptions“. Thesis, University of Wolverhampton, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435666.
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Tran, Chinh Nguyen. „An automatic test generation system for testing virtual memory operations /“. Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Duboc, Jean-Remy. „Dynamic feedback generation in virtual patients using semantic web technologies“. Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/355540/.
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Virtual patients are interactive tools commonly used by medical schools for teaching and learning, and as training tools for the development of clinical reasoning. The feedback delivered to students is a crucial feature in virtual patients. Personalised feedback, in particular, helps students to reflect on their mistakes and to organise their knowledge in order to use it appropriately in a clinical context. However, authoring personalised feedback in virtual patient systems can become a di�cult task, due to the large number of choices available to students and the complex implications of each choice. Additionally, the current technologies used for the design and exchange of virtual patients have limitations in terms of interoperability and data reusability. Semantic web technologies are designed to model complex knowledge in a flexible manner, allowing easy data sharing from multiple sources and automatic data processing. This thesis demonstrates the benefitts of Semantic Web technologies for the design of virtual patients, in particular for the automatic generation of personalised feedback. Seven important types of personalised feedback were identified from the literature, and a preliminary survey showed that students in year 3 to 5 consider two of these types of feedback to be particularly useful: feedback indicating actions that each student should have chosen but neglected, and feedback indicating the diagnoses that each student should have tested and rule out or confi�rmed, given the initial presentation of the patient. SemVP, a Semantic Web-based virtual patient system, was created and evaluated by medical students, using a quantitative survey and qualitative interviews. This study showed that SemVP can generate useful personalised feedback, without the need for a virtual case author to write feedback manually, using a semantic model representing both the virtual patient and each student's actions, and leveraging existing data sources available online.
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Friberg, Oscar. „Investigating urban perception using procedural street generation and virtual reality“. Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-189450.
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As virtual reality and interaction possibilities in game technology evolve and become more user-friendly, accessible and cheaper, this technology suddenly gets useful in occupational areas that traditionally have not used them, one being urban planning. By using a game engine and a virtual neighborhood that utilizes procedural generation the user has the option of having a cost-effective, replicable environment with great control from the user. According to the Broken Windows Theory small differences in appearance can have a big impact on how an urban neighborhood will be perceived. Therefore it would be interesting to investigate how the perception of street scenes is affected by the different aesthetic properties of dirt, graffiti, broken windows, building height and greenery (trees and bushes). By implementing a virtual neighborhood that utilizes procedural generation the basic structure of the neighborhood can stay the same, while separately adjusting the specific properties that are being evaluated. Through surveys and interviews the results show that every one of the chosen properties are very significant except for building height. Generally the more trees that were present, the more safe the neighborhood felt, and the order of significance of dirt, graffiti and broken windows differed between the two evaluation methods.Då virtual reality och interaktionsmöjligheterna inom spelteknologi utvecklas och blir mer användarvänliga, mer tillgängliga och billigare, blir denna teknik plötsligt användbar inom yrkesområden som traditionellt sett inte har använt dem, där ett exempel är stadsplanering. Genom att använda en spelmotor och en virtuell stadsdel som utnyttjar procedural generation får användaren en kostnadseffektiv, replikerbar miljö med stor kontroll från användaren. Enligt Broken Windows Theory så kan små skillnader i utseende ha en stor inverkan på hur en stadsdel kommer att uppfattas. Därför vore det intressant att undersöka hur synen på virtuella gatscener påverkas av olika estetiska egenskaper som smuts, graffiti, trasiga fönster, bygghöjd, och grönska (träd och buskar). Genom att implementera en virtuell stadsdel som utnyttjar procedural generation kan grundstrukturen vara densamma, medan man separat justerar de specifika egenskaperna som ska utvärderas. Genom enkäter och intervjuer visar resultaten att var och en av de valda egenskaperna är mycket betydande, med undantaget för byggnadshöjd. Generellt så kändes stadsdelen mer säker desto mer träd som fanns, och ordningen av signifikansen för smuts, graffiti, och trasiga fönster skiljde sig mellan enkäterna och intervjuerna.
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Buron, Cyprien. „Interactive generation and rendering of massive models : a parallel procedural approach“. Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0014/document.
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Afin de créer des productions toujours plus réalistes, les industries du jeu vidéo et du cinéma cherchent à générer des environnements de plus en plus larges et complexes. Cependant, la modélisation manuelle des objets 3D dans de tels décors se révèle très coûteuse. A l’inverse, les méthodes de génération procédurale permettent de créer facilement une grande variété d’objets, tels que les plantes et les bâtiments. La modélisation par règles de grammaire offre un outil de haut niveau pour décrire ces objets, mais utiliser correctement ces règles s’avère très souvent compliqué. De plus, aucune solution de modélisation basée grammaire ne supporte l’édition et la visualisation d’environnements massifs en temps interactif. Dans un tel scénario, les artistes doivent modifier les objets en dehors de la scène avant de voir le résultat intégré.Dans ces travaux de recherche, nous nous intéressons à la génération procédurale et au rendu d’environnements à grande échelle. Nous voulons aussi faciliter la tâche des artistes avec des outils intuitifs de contrôle de grammaires. Tout d’abord nous proposons un système permettant la génération procédurale en parallèle sur le GPU en temps interactif. Pour cela, nous adoptons une approche d’expansion indépendante par segment, permettant une amplification des données en parallèle. Nous étendons ce système pour générer des modèles basés sur une structure interne, tels que les toits. Nous présentons aussi une solution utilisant des contextes externes pour contrôler facilement les grammaires par le biais de surface ou de texture. Pour finir nous intégrons un système de niveaux de détails et des techniques d’optimisation permettant la génération, l’édition et la visualisation interactives d’environnements à grande échelle. Grâce à notre système il est possible de générer et d’afficher interactivement des scènes comprenant des milliers de bâtiments et d’arbres, représentant environ 2 téraoctets de donnéesWith the increasing computing and storage capabilities of recent hardware, movie and video games industries desire huger realistic environments. However, modeling such sceneries by hand turns out to be highly time consuming and costly. On the other hand, procedural modeling provides methods to easily generate high diversity of elements such as vegetation and architecture. While grammar rules bring a high-level powerful modeling tool, using these rules is often a tedious task, necessitating frustrating trial and error process. Moreover, as no solution proposes real-time generation and rendering for massive environments, artists have to work on separate parts before integrating the whole and see the results.In this research, we aim to provide interactive generation and rendering of very large sceneries, while offering artist-friendly methods for controlling grammars behavior. We first introduce a GPU-based pipeline providing parallel procedural generation at render time. To this end we propose a segment-based expansion method working on independent elements, thus allowing for parallel amplification. We then extend this pipeline to permit the construction of models relying on internal contexts, such as roofs. We also present external contexts to control grammars with surface and texture data. Finally, we integrate a LOD system with optimization techniques within our pipeline providing interactive generation, edition and visualization of massive environments. We demonstrate the efficiency of our pipeline with a scene comprising hundred thousand trees and buildings each, representing 2 terabytes of data
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Ringqvist, David. „Perceptual evaluation of plausibility of virtual furniture layouts“. Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-229905.
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As realistic virtual environments become more important, it is interesting to examine procedural generation. In this work, plausibility of virtual furniture layouts was evaluated in a perceptual study comparing layouts by a professional human interior designer with layout variants rearranged by a C# algorithm. It attached related furniture sides at specified distances in groups. Rasterized furniture footprints were tested, and layouts without overlaps between furniture or their clearance areas were accepted. The algorithm was inspired by Germer and Schwarz (Computer Graphics Forum, 28(8), pp. 2068–2078. 2009), and the evaluation methodology by Yu et al. (ACM Transactions on Graphics, 30(4), pp. 1–11. 2011). The algorithm was run by a Unity tool which placed furniture models in a virtual 3D room. Human-made layouts were also visualized and all layouts presented for 2 and 10 seconds with participants tasked to assess if they were human-made or not. The algorithm fulfilling side-based spatial relation constraints and clearance area constraints did not prove to produce as plausible virtual layouts as those by a human designer, but these constraints significantly improved the perceptual plausibility versus semi-arbitrary furniture placement with only wall-placement constraints for relevant furniture. Perceived orderliness of both human-made and generated layouts was significantly positively correlated with plausibility. The evaluation also provided knowledge of what characteristics are perceived as tells of procedural generation rather than human interior design.Då realistiska virtuella miljöer blir viktigare är det intressant att undersöka processuell generering. I detta arbete utvärderades trovärdigheten av virtuella möbellayouter i en perceptuell studie som jämförde layouter gjorda av en inredningsdesigner med layoutvariationer omarrangerade av en C#-algoritm. Den satte ihop relaterade möbelsidor på specificerade avstånd i grupper. Rasteriserade möbelavtryck testades och layouter utan överlapp mellan möbler eller deras friytor accepterades. Algoritmen var inspirerad av Germer och Schwarz (Computer Graphics Forum, 28(8), s. 2068–2078. 2009) och utvärderingen av Yu et al. (ACM Transactions on Graphics, 30(4), s. 1–11. 2011). Ett Unity-verktyg placerade möbler i ett virtuellt 3D-rum. Designer-layouter visualiserades också och alla layouter visades i 2 & 10 sekunder för deltagare som bedömde om de var arrangerade av människa eller ej. Algoritmen som uppfyllde spatiala sidorelationsvillkor och villkor för fria ytor visade sig inte producera lika trovärdiga virtuella layouter som de gjorda av en människa, men dessa villkor förbättrade trovärdigheten signifikant jämfört med semi-godtycklig möbelplacering med enbart väggplaceringsvillkor för relevanta möbler. Uppfattad nivå av ordning var för både de mänskliga och genererade layouterna signifikant positivt korrelerad med deras trovärdighet. Utvärderingen gav också kunskap om vad som uppfattas som tecken för datorgenerering snarare än mänsklig inredning.
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Moosa, Asaad. „Neural virtual immune system : a next generation web application security framework“. Thesis, University of Reading, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.559257.
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The problem of zero-day attacks in web applications stands as one of the primary challenges against the development of the Internet technology. Solutions so far are not adequate at preventing attacks. The philosophical reasons behind this continuous failure are due to the reliance on out-dated methodologies that offer only signatures-based and anomaly detection solutions. In the last decade, a promising direction in security research utilises biologically inspired computing in which Artificial Immune Systems (AISs) were progressively investigated. Several AIS algorithms and frameworks were introduced in order to simulate the extraordinary capability of the human immune system in eliminating common and emerging pathogenic attacks. However, AISs have not yet provided an ultimate solution to the zero-day attacks problem in web applications. This thesis explores the state-of-the-art in the subject area and shows the limitations and weaknesses of the traditional security solutions as well as the current state of AIS application in security. A novel methodology to tackle the zero-day attacks in web applications is proposed in this thesis and referred to as the Damage Theory. The Damage Theory is derived from a deep understanding of the philosophy of web security as well as the philosophy that inspires the models of the human immune system. Specifically, two biologically inspired computing paradigms: artificial neural networks and artificial immune systems are adopted. The proposed solution is called the Neural Virtual Immune System (NVIS), and it consists of two layers. The first layer mimics the human innate immune system where artificial neural networks handle previously seen attacks. The second layer mimics the human adaptive immune system where data virtualisation and swarm intelligence handle non-previously seen attacks (zero-day). The implementation of NVIS introduces two novel algorithms; namely the Damage Theory Algorithm (DTA) and the Virtual Swarm Tissue Algorithm (VSTA). Both DTA and VSTA algorithms were experimentally tested on case studies where they proved to be effective at preventing SQL injection attacks. iii.
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Clark, Joseph Simon [Verfasser]. „Virtual Design of next-generation zinc-air batteries / Joseph Simon Clark“. Ulm : Universität Ulm, 2019. http://d-nb.info/1200469976/34.
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Chochlidakis, Georgios. „Mobility-aware virtual network embedding techniques for next-generation mobile networks“. Thesis, King's College London (University of London), 2018. https://kclpure.kcl.ac.uk/portal/en/theses/mobilityaware-virtual-network-embedding-techniques-for-nextgeneration-mobile-networks(174e714f-2a4a-447a-bcd5-d526170377fd).html.
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Network virtualisation has become one of the most prominent solutions for sus-tainability towards the dramatic increase of data demand in next-generation mobile networks. In addition, apart from increasing the overall infrastructure utilisation, it also greatly improves the manageability, the scalability and the robustness of the network. In order to allow multiple virtual networks to coexist in the same substrate network, the need for efficient network sharing techniques is imperative. The main purpose of this work is to provide a holistic optimization framework for vir-tual network embedding solutions, where the actual user mobility effect is explicitly considered. First, the main focus is given on the study of the mobility effect and the impact of the mobility management techniques on the end-to-end communication of the mobile user. A hybrid-distributed mobility management scheme is proposed and compared against the latest mobility management schemes. Then, an optimisation framework for efficient mobility-aware virtual network embedding is proposed and evaluated by comparison with other works from the literature. Moving deeper in the area of virtual network embedding, the focus is given on minimizing the end-to-end delay and providing service differentiation, allowing in this way delay sensitive services to use the formed virtual networks with the minimum possible delay, as op-posed to other more elastic services that use the same substrate network. The last part of this work is the study and the analysis of the stochastic nature of the virtual network embedding parameters and the proposal of an optimisation framework for adjustable-robustness virtual network embedding. Driven by the benefits from virtualising the network and its functions, research as well as industry are expected to exploit in a greater degree than today the merits of this concept. The co-existence of multiple tenants not only will greatly change the network industry from a business perspective, but also will emphasise the need for more efficient and flexible network sharing techniques. This work belongs to the initial efforts to embrace and adopt the virtualisation concept in the next-generation wireless networks.
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Williams, Jared Van. „Rocky: virtual sculpting as the basis for computer generated character development“. Thesis, University of Iowa, 2012. https://ir.uiowa.edu/etd/3011.
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Human beings have two perfectly aligned eyeballs working together sending three-dimensional images to the brain and providing accurate depth perception. I lack true stereoscopic vision. When I was five years old I had my second eye surgery and I remember lying blind and terrified for two days in the children's ward of Reid Memorial Hospital in Richmond, Indiana. I later learned that my eyes didn't align properly and for the rest of my life my right eye would "wander". Because of my condition, I was given a list of jobs that I could never perform, jobs where human lives are entrusted to skilled professionals wielding scalpels or landing jets. I could never be one of those people. Or so I was told. I've always had excellent vision, nearly 20/20 my whole life and I've never struggled academically. It's just that my eyes don't point in the same direction like everybody else. Those who know me best can see it, but I've learned ways to make it not so obvious. It's all I've ever known. But, in an ironic twist of fate, it's become clear that my lazy eye has taught me to "see" better than the average artist. Having spent the last five years of my life studying 3D Design and exploring the most advanced creative technology on the planet, I've created a series of computer-generated environments, objects and characters. This is my latest attempt to prove to the world that I can see just fine. I could've been a doctor or a pilot after all. In this paper I present to the world a digital friend manifested from my slightly skewed interpretation of the world. Rocky is part of my imagination brought to life in perfect three-dimensional clarity for the world to see. He's a symbolic representation of my childhood love for cartoons and science fiction. He is strong yet gentle, modest, intelligent and noble. And, he is fiercely protective of that scared and blind five-year old boy.
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Kolhatkar, Shanat. „Real-Time Virtual Viewpoint Generation on the GPU for Scene Navigation“. Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28807.
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In this thesis we present a method for achieving real-time view interpolation in a virtual navigation application that uses a collection of pre-captured panoramic views as a representation of the environment. In this context, viewpoint interpolation is essential to achieve smooth and realistic viewpoint transition while the user is moving from one panorama to another. In this proposed approach, view interpolation is achieved by first computing the optical flow field between a pair of adjacent panoramas. This flow field can then be used by the view morphing algorithm to generate, on-the-fly, virtual viewpoints in-between existing views. Realistic interpolation is obtained by taking into account both scene geometry and color information. To achieve real-time viewpoint interpolation, a GPU implementation of the viewpoint interpolation algorithm has been developed. We ran our algorithm on multiple interior and exterior scenes and we were able to produce smooth and realistic viewpoint transitions by generating virtual views at a rate of more than 300 Panoramas per second.
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Zhu, Lijia. „Example-based natural three-dimensional expression generation for virtual human faces“. Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27435.
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This thesis proposes a methodology which produces natural facial expressions for 3D human face models by making use of a databank. Firstly, guided by the specified feature point motions, an approach is introduced for generating facial expressions by blending the examples in an expression databank. The optimized blending weights are obtained implicitly by Genetic Algorithms (GA). Secondly, a consistent parameterization technique is shown to model the desired structured human face by processing the raw laser-scanned face data. Based on this technique, we construct a facial motion databank consisting of consistent facial meshes. Thirdly, rather than producing novel facial expressions for a different subject from scratch, an efficient method is presented to retarget facial motions from one person to another. Finally, these techniques are combined together to reconstruct the 3D facial motions (surface motions) based on the motion capture data (feature point motions).
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Ertoptamis, Ozge. „Enhancing Creativity In The Concept Generation Phase: Implementation Of Black Box As A Tool For Analogical Reasoning“. Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608219/index.pdf.
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In recent years, the field of design has met new grounds with the growing awareness among design researchers of the potential relationships between cognitive studies of creativity and computational modeling. The turn of the studies has given rise to the emergence of a new paradigm of modeling and understanding mental processes in creative design. This study tries to gain further insight into the creative occurrence by blending virtual experiences with designer actions in a model of creative thinking in concept generation phase based on the Geneplore Model by Finke et al. (1995) and supported by analogy construction incorporating the implementation of a computer based tool (Black Box) running on PC platform as a potential immanent part of the concept generation phase.
Black Box is devised in such a way that the core of the constructive process of the analogy relies on the designer’
s expressional, perceptual and conceptual actions which are presented in the traditional methods of sketching and writing, whereas the change and expansion of the design space is realized through the virtual worlds the tool offers via the computer screen. The research method is based on the development of Black Box tool and its subsequent implementation in a study with eight experienced design consultants, utilizing a procedure composed of preliminary interview, observational protocol analysis, questionnaire and retrospective interview. Through encoding actions of individual designers by means of their maps in the computational tool, the study yields significant results in revealing differing thinking maps of different designers which have been used to propose a general creative thinking map of concept generation in Black Box presented in a way to be adapted for further studies. Moreover, the study provided insight on the methods used to assist creativity in concept generation by different designers, on the selection of inspirational material and on the integration of analogies as knowledge transformers to evoke design concepts.
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Ketterer, Hoppe Javiera Ninel. „Metodología Básica para la Definición de la Ubicación Óptima de un Generador Virtual“. Tesis, Universidad de Chile, 2009. http://www.repositorio.uchile.cl/handle/2250/103365.
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La energía eléctrica es un recurso necesario en la vida de todos, verificándose que la demanda energética de un país se encuentra, por lo general, correlacionada con su PIB. Lo anterior conlleva a la instalación o reposición de nuevas centrales de energía eléctrica y a la necesidad de aumentar la eficiencia del sistema.
En este contexto se introducen las tecnologías de generación distribuida (GD), basadas en energía renovable. Estas tecnologías corresponden a centrales de mediana y pequeña escala, que se encuentran conectadas directamente a los sistemas de distribución. Pueden ser propiedad de los consumidores o de las empresas distribuidoras y entregan sus excedentes de generación al sistema. Debido a su favorable ubicación, la GD puede ayudar a mejorar la calidad de servicio necesaria para los consumos. Esto es posible si existe una correcta ubicación, conexión y coordinación de la GD. En este contexto se introduce el concepto de Generador Virtual (GV), ente encargado de la coordinación de la operación de distintas unidades de GD, de manera de optimizar su desempeño conjunto.
El objetivo principal del presente trabajo de título es disponer de una metodología para determinar la ubicación óptima de un GV. Para ello, se efectúa un estudio detallado de las tecnologías implementadas en GD, en particular aquellas que utilizan recursos renovables. Se establecen las condiciones necesarias para determinar el mejor emplazamiento, basado en las características del recurso energético primario con datos estadísticos y las características de las redes de distribución (ubicación y capacidad). Con el fin de estipular los parámetros que determinan el punto de conexión a la red, se estudia la influencia de la GD en el sistema, como son: la influencia que ejercen los GD en los niveles de tensión en los distintos nodos donde se encuentran insertos, la reducción de pérdidas óhmicas relacionadas con la combinación de GD y servicios que pueden proporcionar un GV (regulación de tensión, continuidad de suministro, etc. los que entregan una mayor rentabilidad a este tipo de energías).
Si bien la metodología es validada en forma conjunta, se presenta su aplicación a casos específicos de energía solar, eólica, biomasa y minihidráulica en la localidad de Ovalle y Salamanca. Los resultados obtenidos corroboran el potencial de aplicación práctica de la propuesta. Por último, como trabajo a futuro se recomienda establecer los niveles máximos de penetración de las distintas tecnologías en una red de distribución y desarrollar modelos que representen los efectos de combinar diversas tecnologías de GD en una misma red.
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Lundkvist, Johanna. „Feasibility study of a VirtualPower Plant for Ludvika“. Thesis, Uppsala universitet, Fasta tillståndets fysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-201895.
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This thesis is a feasibility study of avirtual power plant (VPP) in centralSweden and part of a project withInnoEnergy Instinct and STRI. The VPPconsists of a wind park, small hydroplant as well as solar photovoltaic andenergy storage. The 50 kVsubtransmission network was modeled inorder to evaluate the network servicesthat could be provided by coordinatingexisting distributed energy resources inthe network. Simulations where performedusing measured hourly variations inproduction and consumption of allnetwork nodes. The studied networkservices included both reactive andactive power control.The aim of this thesis is to evaluatethe potential contribution from the VPPfor capacity firming in order to allow abalance responsible party to meet placedbids on the day-ahead spot market,minimize peak load in order to reducesubscribed power, decrease networklosses, the contribution from reactivepower control using the power convertersis studied. Comparisons of the economicgains from spot and balance markets ofthe VPP distributed energy resources aremade for each operation case.Sponsor: InnoEnergyInnoEnergy Instinct
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Sjölie, Daniel. „Human brains and virtual realities : Computer-generated presence in theory and practice“. Doctoral thesis, Umeå universitet, Institutionen för datavetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-68664.
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A combined view of the human brain and computer-generated virtual realities is motivated by recent developments in cognitive neuroscience and human-computer interaction (HCI). The emergence of new theories of human brain function, together with an increasing use of realistic human-computer interaction, give reason to believe that a better understanding of the relationship between human brains and virtual realities is both possible and valuable. The concept of “presence”, described as the subjective feeling of being in a place that feels real, can serve as a cornerstone concept in the development of such an understanding, as computer-generated presence is tightly related to how human brains work in virtual realities. In this thesis, presence is related both to theoretical discussions rooted in theories of human brain function, and to measurements of brain activity during realistic interaction. The practical implications of such results are further developed by considering potential applications. This includes the development and evaluation of a prototype application, motivated by presented principles. The theoretical conception of presence in this thesis relies on general principles of brain function, and describes presence as a general cognitive function, not specifically related to virtual realities. Virtual reality (VR) is an excellent technology for investigating and taking advantage of all aspects of presence, but a more general interpretation allows the same principles to be applied to a wide range of applications. Functional magnetic resonance imaging (fMRI) was used to study the working human brain in VR. Such data can inform and constrain further discussion about presence. Using two different experimental designs we have investigated both the effect of basic aspects of VR interaction, as well as the neural correlates of disrupted presence in a naturalistic environment. Reality-based brain-computer interaction (RBBCI) is suggested as a concept for summarizing the motivations for, and the context of, applications building on an understanding of human brains in virtual realities. The RBBCI prototype application we developed did not achieve the set goals, but much remains to be investigated and lessons from our evaluation point to possible ways forward. A developed use of methods and techniques from computer gaming is of particular interest.Ett kombinerat perspektiv på den mänskliga hjärnan och datorgenererade virtuella verkligheter motiveras av den senaste utvecklingen inom kognitiv neurovetenskap och människa-datorinteraktion (MDI). Framväxten av nya teorier om den mänskliga hjärnan, tillsammans med en ökande användning av realistisk människa-datorinteraktion, gör det troligt att en bättre förståelse för relationen mellan mänskliga hjärnor och virtuella verkligheter är både möjlig och värdefull. Begreppet "närvaro", som i detta sammanhang beskrivs som den subjektiva känslan av att vara på en plats som känns verklig, kan fungera som en hörnsten i utvecklingen av en sådan förståelse, då datorgenererad närvaro är tätt kopplat till hur mänskliga hjärnor fungerar i virtuella verkligheter. I denna avhandling kopplas närvaro både till teoretiska diskussioner grundade i teorier om den mänskliga hjärnan, och till mätningar av hjärnans aktivitet under realistisk interaktion. De praktiska konsekvenserna av sådana resultat utvecklas vidare med en närmare titt på potentiella tillämpningar. Detta inkluderar utveckling och utvärdering av en prototypapplikation, motiverad av de presenterade principerna. Den teoretiska diskussionen av närvaro i denna avhandling bygger på allmänna principer för hjärnans funktion, och beskriver känslan av närvaro som en generell kognitiv funktion, inte specifikt relaterad till virtuella verkligheter. Virtuell verklighet (virtual reality, VR) är en utmärkt teknik för att undersöka och dra nytta av alla aspekter av närvaro, men en mer allmän tolkning gör att samma principer kan tillämpas på ett brett spektrum av applikationer. Funktionell hjärnavbildning (fMRI) användes för att studera den arbetande mänskliga hjärnan i VR. Sådant data kan informera och begränsa en vidare diskussion av närvaro. Med hjälp av två olika försöksdesigner har vi har undersökt både effekten av grundläggande aspekter av VR-interaktion, och neurala korrelat av störd närvaro i en naturalistisk miljö. Verklighets-baserad hjärna-dator interaktion (reality-based brain-computer interaction, RBBCI) föreslås som ett begrepp för att sammanfatta motiv och kontext för applikationer som bygger på en förståelse av den mänskliga hjärnan i virtuella verkligheter. Den prototypapplikation vi utvecklade uppnådde inte de uppsatta målen, men mycket återstår att utforska och lärdomar från vår utvärdering pekar på möjliga vägar framåt. En vidare användning av metoder och tekniker från dataspel är speciellt intressant.
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Milius, Jeannette. „Generation and Implementation of Virtual Landscapes for an Augmented Reality HMI-Laboratory“. Master's thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-133307.
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Three dimensional visualisation achieves tremendous savings in time and costs during the design process. Due to these circumstances this methods are gaining in importance. For example improvement in performance and the product security or enabling the operative optimization of a production sequence. By the virtual testing it is possible to validate a product in the whole developing process and product lifecycle. The flight simulator ATILa at Airbus Defence and Space in Friedrichshafen uses these advantages for own products. ATILa is used to test intelligent assistance systems for helicopter pilots. Here the graphic implementation of the virtual earth plays a key role when practicing realistical scenarios. This approach is implemented with the Common Database (CDB) which is enabled by the definition of specifications and standards. Different commercial software packages by Presagis are used to implement the aforementioned database. The software Terra Vista is used for the database generation, including the compilation. For the CDB implementation the software Vega Prime is used to prepare the data with the help of the RTP. The software Vega Prime is not able to display 3D models with LODs, due to a software error. Therefore a third software named Creator is used to modify them. The 3D models are available in the OpenFlight Format. This OpenFlight format consists of different kind of nodes with a complex hierarchical structure. Other software solutions, such as Autodesk or Blender, are not able to provide access to the specific structure. The edited models can be integrated in the virtual environment and have to defined by unambiguous indices. Various settings are used to implement the objects automatically. The compilation of the area of interest takes place by the definition of a geotile with a specific size depending on the latitude. The CDB ouput will be transferred by Vega Prime and with the help of the RTP into the simulator. In addition, there is the possibility to render various CDB databases in the simulator to enable a visualisation of the complete earth. Finally, any errors occurring will be described and methods of resolution explained. The complexity of the generation process of a CDB database could be represented with this thesis. However, the whole workflow of the visualisation of the earth is still in its initial stages, since among other things there are errors in the software. To sum up; the potential of the CDB can be evaluated as above averageDie 3D Visualisierung vereinfacht den Planungsprozess und geht somit mit einer Zeit- und Kosten- einsparung einher. Aufgrund dieser Sachverhalte gewinnt sie immer weiter an Bedeutung, um zum Beispiel eine verbesserte und sichere Benutzung eines Produktes oder einen optimierten Betrieb einer Produktionskette zu ermöglichen. Durch vorherige virtuelle Erprobung und Vali- dierung eines Produktes können Kosten für den gesamten Entwicklungsprozess und den Pro- duktlebenszyklus gering gehalten werden. Im Flugsimulator für Helikopter namens ATILa in Friedrichshafen (Airbus Defence and Space) versucht man die genannten Vorteile für die eigenen Produkte zu nutzen. Im ATILa werden Assistenzsysteme geprüft, welche die Helikopterpiloten während ihres Fluges unterstützen sollen. Hierbei spielt die grafische Umsetzung der virtuellen Erde in dem Simulator eine entscheidende Rolle, um die Szenarien realitätsnah durchführen zu können. Dies kann mit Hilfe einer sogenannten Common Database (CDB), die durch Spezi- fikationen und Standards definiert ist, umgesetzt werden. Mittels verschiedener kommerzieller Softwarepakete der Firma Presagis lässt sich die oben genannte Datenbank erstellen. Die Gener- ierung und Kompilierung wird mit dem Softwareprogramm Terra Vista vorgenommen. Die Imple- mentierung der CDB in den Flugsimulator erfolgt mit der Software Vega Prime, welche die Daten über einen RTP zur Verfügung stellt. Da dieses Programm durch einen Softwarefehler nicht in der Lage ist, 3D Modelle mit verschiedenen Detaillierungsgraden darzustellen, muss eine dritte Soft- ware namens Creator genutzt werden. Die 3D Modelle liegen im OpenFlight Format vor. Dieses OpenFlight Format weist eine komplexe hierarchische Struktur aus verschiedenen Knoten auf. Andere Softwarelösungen, wie Autodesk oder Blender, sind nicht in der Lage einen Einblick in die spezielle Struktur zu geben. Die bearbeiteten Modelle können dann in der virtuellen Umgebung eingebunden und müssen durch eindeutige Indizes definiert werden. Verschiedene Einstellun- gen werden genutzt, um Objekte automatisch einzubinden. Die Kompilierung des Interessenge- bietes erfolgt über die Definition einer Geokachel mit einer bestimmten Größe, die abhängig vom Breitengrad ist. Die ausgegebene CDB wird mit Vega Prime und mit Hilfe des RTPs in den Simu- lator übertragen. Des Weiteren gibt es die Möglichkeit verschiedene CDB Datenbanken im Sim- ulator simultan zu rendern, was eine vollständige Visualisierung der kompletten Erde ermöglicht. Abschließend werden aufgetretene Fehler näher beschrieben und Lösungsansätze erläutert. Mit der vorliegenden Arbeit konnte die Komplexität der Entstehung einer CDB Datenbank dargestellt werden. Dennoch befindet sich der gesamte Arbeitsablauf der Visualisierung der Erde noch am Anfang, da u.a. Softwarefehler zu bemängeln sind. Zusammenfassend kann das Potenzial einer CDB als überdurchschnittlich bewertet werden
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Roos, Daniel, und Gustav Aaro. „A Toolset for Qualitative Dataset Generation of Virtual Reality Environment User Interaction“. Thesis, Linköpings universitet, Institutionen för datavetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-148667.
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Virtual reality (VR) is a medium of human interaction which is becoming more popular by the day in today's technological advancements. The applications are being developed at the same rate as the technology itself and we have only seen the start of the possible benefits it could bring society. As the technology advances it will gain a lot of trust, and the potential use cases of virtual environments will be allowed to become more complex. Already today, they often involve network streaming components which often has very strict optimization requirements in order to be able to run in real-time with minimal delay under normal network conditions. In order to reach the required optimizations it is important to understand how users interact with such virtual environments. To support and facilitate the understanding of this kind of interaction we have developed a method for creating qualitative datasets containing extensive information about the 3D scene as well as the sensor data from the head-mounted display (HMD). We then apply this method to create a sample dataset from a virtual 3D environment and try to analyze the data collected through some simple methods for demonstrational purposes.
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Schoop, Eric, Claudia Lieske und Helena Bukvova. „Virtual Collaborative Learning: Auf der Suche nach den Digital Natives“. Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-26206.
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Dieser Beitrag untersucht die These über die Existenz von Digital Natives. Die Vertreter dieser These postulieren, dass Studenten und Schüler durch den frühen Kontakt mit Informations- und Kommunikationstechnologien hinsichtlich ihres Lern-, Arbeits- und Kommunikationsverhaltens wesentlich verändert wurden. Um diese Aussage zu bewerten, werden Erfahrungen mit Virtual Collaborative Learning Veranstaltungen herangezogen. Die aktuellste durchgeführte Veranstaltung wird als Fallstudie vorgestellt und analysiert.
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Schramm, Jonathan. „Analysis of Third Person Cameras in Current Generation Action Games“. Thesis, Högskolan på Gotland, Institutionen för speldesign, teknik och lärande, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hgo:diva-1903.
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The purpose of this project was to research the virtual camera systems used in current generation third person action games and to see what could be improved upon. To do this, different camera shots were categorized into camera archetypes, which also include post process and lens effects used. Information about the games was acquired by either looking through the game’s settings or by observing gameplay. Finally the results were compared to each other as well as the film industry and several improvements regarding usage of different features and camera shots were suggested.
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Satoh, Satoshi, Kenji Fujimoto und Sang-Ho Hyon. „A framework for optimal gait generation via learning optimal control using virtual constraint“. IEEE, 2008. http://hdl.handle.net/2237/12079.
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Walker, Alexander D. „The role of head movements in simulator sickness generated by a virtual environment“. Connect to this title online, 2008. http://etd.lib.clemson.edu/documents/1211387072/.
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Yan, Xingyu. „Assembly simulation and evaluation based on generation of virtual workpiece with form defect“. Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0008/document.
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La géométrie d'une pièce fabriquée réelle diffère de la pièce virtuelle de CAO (Conception Assistée par Ordinateur. Cette différence est due à la somme des écarts inhérents à la fabrication. L'objectif de ce travail est d’introduire des pièces virtuelles ayant des défauts de forme (Skin Model Shape) dans les applications d'ingénierie afin de répondre aux exigences croissantes de l'industrie en matière de gestion de la qualité de la géométrie des produits. Les travaux traitent de divers aspects, particulièrement de la génération de défauts de forme, de la simulation d'assemblage et de la métrologie virtuelle.Les méthodes permettant de générer des défauts de forme sur des surfaces simples sont analysés et classées. En raison des défauts de forme, la combinaison de surfaces simples pour générer une pièce entière induit une incohérence géométrique au niveau des arêtes. Une méthode globale basée sur les éléments finis et une méthode locale basée sur le lissage local de maillage sont utilisées pour résoudre ce problème.Pour prédire l'écart des caractéristiques fonctionnelles, la simulation d'assemblage est effectuée en utilisant des surfaces avec défauts de forme. Une approche est développée sur la base de la condition de complémentarité linéaire et du torseur de petits déplacements pour prendre en compte les conditions aux limites de l'assemblage, telles que les déplacements et les charges.Des méthodes pour évaluer les écarts sur les modèles de surfaces avec défauts de forme sont également étudiées. Les spécifications sur le produit sont exprimées avec GeoSpelling et évaluées à l'aide du torseur de petits déplacements. Les méthodes développées sont intégrées dans un laboratoire virtuel pour l'apprentissage en ligne.Les études susmentionnées complètent et étendent les méthodes de gestion des tolérances basées sur GeoSpelling et le « skin » modèleThe geometry of a real manufactured part differs from the virtual workpieces designed in Computer Aided Design (CAD) systems. This difference is due to the accumulation of unavoidable manufacturing deviations. The objective of this work is to implement virtual workpieces with form defects (Skin Model Shape) in engineering applications to meet the industry’s increasing demands in product geometry quality management. Various aspects are covered here, in particular form defect generation, assembly simulation and virtual metrology.Methods to generate form defects on simple surfaces are reviewed and classified. Due to form defects, the combination of simple surfaces to generate a whole part led to inconsistency on the edges. A global FEA-based method and a local mesh smoothing based method are used to overcome this issue.To predict the deviation of functional characteristics, assembly simulation is conducted using skin model shapes. An approach is developed based on the Linear Complementarity Condition and the Small Displacement Torsor to take into account assembly boundary conditions, such as displacements and loads.Methods to evaluate deviation values on skin model shapes are also studied. Product specifications are expressed with GeoSpelling, and evaluated using the Small Displacement Torsor method. The developed methods are integrated into an online Virtual Laboratory for e-learning.The above-mentioned studies complement and extend the tolerance management methods based on GeoSpelling and skin models
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Ahmad, Bilal. „A component-based virtual engineering approach to PLC code generation for automation systems“. Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/16060.
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In recent years, the automotive industry has been significantly affected by a number of challenges driven by globalisation, economic fluctuations, environmental awareness and rapid technological developments. As a consequence, product lifecycles are shortening and customer demands are becoming more diverse. To survive in such a business environment, manufacturers are striving to find a costeffective solution for fast and efficient development and reconfiguration of manufacturing systems to satisfy the needs of changing markets without losses in production. Production systems within automotive industry are vastly automated and heavily rely on PLC-based control systems. It has been established that one of the major obstacles in realising reconfigurable manufacturing systems is the fragmented engineering approach to implement control systems. Control engineering starts at a very late stage in the overall system engineering process and remains highly isolated from the mechanical design and build of the system. During this stage, control code is typically written manually in vendor-specific tools in a combination of IEC 61131-3 languages. Writing control code is a complex, time consuming and error-prone process.
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Wang, Fang. „Study of an adaptive and multifunctional computational behaviour generation model for virtual creatures“. Thesis, University of Edinburgh, 2002. http://hdl.handle.net/1842/13189.
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High fidelity virtual environments can be inhabited by virtual creatures. A virtual creature should be able to learn itself how to improve its old behaviors and produce new related behaviors so as to be more adaptive and autonomous and hence reduce human design work. This thesis presents a study of an adaptive and multifunctional Computational Behavior Generation (CBG) model for virtual creatures with the ultimate goal of enhancing a creature's adaptation and multifunctionality in behavior control by learning. Specifically, we require that the CBG model can learn to perform variable behavior tasks in various environments and situations. The design of the CBG model is inspired by the natural behavior control system in the brain. It can perform the whole procedure of decision, programming and execution of motor actions, and its hierarchical architecture provides the material basis for its adaptive and multifunctional learning implementation. The concrete achievement of adaptation and multifunctionality by learning is obtained with the help of a Multiagent based Evolutionary Artificial Neural Network with Lifetime Learning (MENL), which can learn to make correct action decisions for varied behavior tasks in varied situations. MENL takes advantage of the whole population information of evolution by maintaining a batch of multiagents in every evolutionary generation. These agents co-decide the decisions to be executed, and they are subject to evolutionary learning through all of their lifetime. The fitness function of MENL is designed without many specific constraints, and can be easily extended for a variety of behaviors. As a consequence, the CBG with MENL can obtain high adaptation and generalization in behavior. The CBG model combined with the MENL learning algorithm enables a virtual creature to learn several general navigation functions independently and jointly in unknown environments. These functions include exploration, goal reaching, and wandering. The virtual creature is first asked to learn general exploration only in a series of increasing complex environments. This creature has adapted to various environments and navigated in them successfully. The whole successful exploration experiment is achieved due to the competition and emergent cooperation among multiagents and their continuous lifetime learning.
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Sandercock, Jennifer Ellen, und jenn@jennsand com. „Using adaptation and goal context to automatically generate individual personalities for virtual characters“. RMIT University. Computer Science and Information Technology, 2010. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20100205.162047.
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Personality is a key component of characters that inhabit immersive virtual environments, such as games and virtual agent applications. In order to be distinguishable from other characters in the environment, each character should have its own personality in the form of different observable behaviour, not solely in its physical appearance or animation. Previous work in this field has mostly relied on time-consuming, handcrafted characters and static, trait-based approaches to personality. Our goal is a method to develop complex, individual personalities without handcrafting every behaviour. Unlike most implemented versions of personality theories, cognitive-social theories of personality address how personality is developed and adapts throughout childhood and over our lifetimes. Cognitive-social theories also emphasise the importance of situations in determining how we behave. From this basis, we believe that personality should be individual, adaptive, and based on context. Characters in current state-of-the-art games and virtual environments do not demonstrate all of these features without extensive handcrafting. We propose a model where personality influences both decision-making and evaluation of reward. Characters use their past experiences in the form of simple somatic markers, or gut-instinct, to make decisions; and determine rewards based on their own personal goals, rather than via external feedback. We evaluated the model by implementation of a simple game and tested it using quantitative criteria, including a purpose-designed individuality measure. Results indicate that, although characters are given the same initial personality template, it is possible to develop different personalities (in the form of behaviour) based on their unique experiences in the environment and relationships with other characters. This work shows a way forward for more automated development of personalities that are individual, context-aware and adapt to users and the environment.
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Chamakiotis, Petros. „Exploring creativity in temporary virtual teams : the case of engineering design“. Thesis, University of Bath, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619239.
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The prevalence of Virtual Team (VT) configurations in organizations has come to challenge the relevance of traditional management practices based on traditional, physically collocated teams. Creativity—a topical and multidisciplinary issue—has been under-researched within the context of virtuality. Predicated on the premise that creativity may be expressed differently in the context of VTs, I draw the conceptual foundations for this research from the fields of virtuality (i.e. VTs) and creativity, and use engineering design as the empirical context, with the aim of pursuing a better understanding of creativity in relationship with virtuality in the context of Virtual Design Teams (VDTs). Design constitutes a pertinent empirical context because (a) designers have to deliver outputs requiring creativity; and (b) their work is increasingly accomplished in VDT environments. I report on the findings from three case studies involving temporary VDTs. Studies 1 and 2 comprised student engineers. Study 3 was a comparative case study focusing on a team of professional engineers, who completed one design task while physically collocated (face-to-face, F2F) and another one while geographically dispersed (virtually), with the aim of isolating factors that are unique to virtuality. With an interpretive stance guiding this research, the same analytical approach for each case study, and with the team serving as the unit of analysis, I analysed the collected data (interview data, observations, video recordings, photographic material, documents, communication extracts, design and other outputs) qualitatively with the use of visual and thematic analysis. The thesis makes the following theoretical contributions: (a) it advances understanding of creativity within the VDT lifecycle; (b) it elicits factors influencing creativity in the temporary VDT context; and (c) it explains how the unique characteristics of virtuality influence creativity within this context. The thesis’ limitations as well as implications for research and practice are also discussed.