17 research outputs found

    Algoritmos para a determinação da região coberta por um k-transmissor

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    Mestrado em Matemática e AplicaçõesOs problemas de visibilidade/cobertura têm diversas aplicações a situa ções reais. Os mais recentes são inspirados nas novas tecnologias, envolvendo dispositivos de rede sem os. Neste trabalho será abordado o problema de determinar a região coberta pelo sinal emitido por um destes dispositivos, colocado em estruturas geométricas conhecidas como polígonos, uma vez que estes podem representar, de forma apropriada, a geometria de edifícios e são de fácil manipulação computacional, podendo o sinal estudado atravessar um dado número de obstáculos (parades/arestas do polígono), razão pela qual os dispositivos são chamados de k-transmissores, de acordo com o número de obstáculos que o sinal emitido é capaz de atravessar. A resolução deste problema torna-se importante, não só pela sua aplicação directa, mas principalmente porque permitirá prosseguir estudos relacionados, como o problema da determinação do número mínimo de posições para a colocação destes dispositivos num dado polígono, de modo a que os sinais por eles emitidos consigam cobrir a totalidade do polígono. Nesta dissertação são referidos os algoritmos existentes para a resolu- ção do problema da determinação da região coberta pelo sinal emitido por um dispositivo de redes sem os, colocado num polígono simples, e são apresentados dois novos algoritmos para a resolução desse mesmo problema. Com o objectivo de testar e avaliar experimentalmente os algoritmos apresentados e de facilitar o prosseguimento de estudos relacionados, foi desenvolvida uma aplicação que inclui uma interface grá ca para facilitar a introdução de dados de entrada (vértices do polígono e dados relativos aos dispositivos) e a visualização dos resultados (região coberta pelo sinal) por parte do utilizador. Esta aplicação é descrita de forma detalhada nesta dissertação.Visibility/coverage problems have several applications to real-life situations. The most recent coverage problems are inspired by new technologies and envolve wireless devices. This work deals with the problem of nding the covered region by the signal of these devices, located on geometrical structures known as polygons, since polygons are appropriate representations of objects geometry and are easily handled by computers. Notice that the signal of those devices can cross a certain number k of walls (edges of the polygon) and that is the reason why the devices are called k-transmitters. The determination of solutions to this problem is important not only because of its direct application but also (and mainly) because it will make possible to proceed related studies, like the problem of nd a minimum number of device positions on a given polygon such that these devices collectively cover the whole polygon. In this dissertation, we refer the existing algorithms to solve the problem of nding the covered region by the signal transmitted by a wireless device, located on a simple polygon, and two new algorithms to also solve this problem are presented. To experimentally test and evaluate the analyzed algorithms and to become easier to proceed related studies, an application that includes a graphic interface has been developed to make it possible for the user to easily insert data (the vertices of the polygon and the information related to devices) and visualize the nal results (the covered region). There is a detailed description of that application in this thesis

    Haptic holography : an early computational plastic

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2001.Includes bibliographical references (p. 135-148).This dissertation introduces haptic holography, a combination of computational modeling and multimodal spatial display, as an early computationalplastic In this work, we combine various holographic displays with a force feedback device to image free-standing material surfaces with programmatically prescribed behavior. We present three implementations, Touch, Lathe, and Poke, each named for the primitive functional affordance it offers. In Touch, we present static holographic images of simple geometry, reconstructed in front of the hologram plane (in the viewer's space), and precisely co-located with a force model of the same geometry. These images can be visually inspected and haptically explored using a hand-held interface. In Lathe, we again display holo-haptic images of simple geometry, this time allowing those images to be reshaped by haptic interaction in a dynamic but constrained manner. Finally in Poke, we present a holo-haptic image that permits arbitrary reshaping of its reconstructed surface. As supporting technology, we offer a new technique for incrementally computing and locally updating interference-modeled holographic fringe patterns. This technique permits electronic holograms to be updated arbitrarily and interactively, marking a long-held goal in display holography. As a broader contribution, we offer a new behavior-based spatial framework, based on both perception and action, for informing the design of spatial interactive systems.Wendy J. Plesniak.Ph.D

    CIRA annual report FY 2014/2015

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    Reporting period July 1, 2014-March 31, 2015

    Integrated Optical Interferometers with Micromachined Diaphragms for Pressure Sensing

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    Optical pressure sensors have been fabricated which use an integrated optical channel waveguide that is part of an interferometer to measure the pressure-induced strain in a micromachined silicon diaphragm. A silicon substrate is etched from the back of the wafer leaving a rectangular diaphragm. On the opposite side of the wafer, ring resonator and Mach-Zehnder interferometers are formed with optical channel waveguides made from a low pressure chemical vapor deposited film of silicon oxynitride. The interferometer's phase is altered by pressure-induced stress in a channel segment positioned over the long edge of the diaphragm. The phase change in the ring resonator is monitored using a link-insensitive swept frequency laser diode, while in the Mach-Zehnder it is determined using a broad band super luminescent diode with subsequent wavelength separation. The ring resonator was found to be highly temperature sensitive, while the Mach-Zehnder, which had a smaller optical path length difference, was proportionally less so. The quasi-TM mode was more sensitive to pressure, in accord with calculations. Waveguide and sensor theory, sensitivity calculations, a fabrication sequence, and experimental results are presented

    Cognitive aspects of work with digital maps

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    Digital maps of geographic areas are increasingly common in many types of workplace, in education and in the public domain. Their interactivity and visual features, and the complexity of geographic(al) information systems (GIS) which create, edit and manipulate them, create special cognitive demands on the end-user which are not present in traditional cartographic maps or in most human-computer interaction (HCI). This thesis reviews cross-disciplinary literature regarding cognitive aspects of viewing and interacting with digital maps. Data from an observational study of GIS use, including real-time recordings of normal workplace activities, was analysed using various approaches to examine the interactive and visual aspects of people's work. The implications for cartographic, psychological and HeI aspects of GIS are discussed, in the context of the actual tasks people perform with them (rather than the computationally advanced analyses assumed by most literature). The second phase of the research examined the spatial knowledge attained and used during this interaction. The relevance of specific concepts in cognitive psychology, and of factors that create individual differences in cognition, are discussed in depth, alongside work in environmental and educational psychology, cartography and geography. A controlled experiment examined the degree to which task characteristics induce a different spatial model or reference frame when viewing a digital map. It was shown that even novice users can switch between considering the map as an abstract geometric display or as a geographical representation, without affecting performance. However, tasks forcing subjects to focus entirely on the geometry rather than the geography did affect performance in a surprise post-test photograph identification task. Map users' mental model or reference frame is apparently affected by these task constraints; this has implications for GIS design and practice as well as for understanding spatial cognition The study also considered the role of expertise and other individual difference factors, although conclusions were limited by sample size. Further research issues are highlighted, particularly regarding the knowledge structures and spatial language used in interpreting digital maps

    HyperBody: An Experimental VR Game Exploring the Cosmotechnics of Game Fandom through a Posthumanist Lens

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    Interdependencies among ACGN (Anime, Comics, Games, and Novels) communities in China, Hong Kong, and Taiwan are growing. However, game studies and fan studies remain distinct disciplines. This cross-disciplinary thesis bridges this gap by investigating "game-fandom" practices in VR production, defined as the fusion of game and fan studies within the ACGN context. Drawing from Yuk Hui's "cosmotechnics" and Karen Barad's posthumanist perspective, this research reconsiders the relationship between cosmology, morality, and technology (Hui 2017). It employs "intra-action" to emphasise the indivisible, dynamic relations among specified objects (Barad 2007). Cultural practices in C-pop idol groups, Chinese BL (Boys' Love) novels, science fiction, and modding communities are analysed, illuminating the ACGN fandom's cultural, technological, and affective dimensions. This work features the creation, description, and evaluation of an experimental VR game, "HyperBody", which integrates the written thesis by reflecting game-fandom's cosmotechnics and intra-actions. The thesis offers two significant contributions: "queer tuning", a theory illuminating new cultural, technological, and affective turns within fandom and computational art, and a "diffractive" approach, forming a methodological framework for posthuman performative contexts. This diffractive framework enables practical contributions such as creating and describing experimental VR productions using the sound engine. It also highlights a thorough evaluation approach reconciling quantitative and qualitative methods in VR production analysis, investigating affective experiences, and exploring how users engage creatively with queer VR gamespaces. These contributions foster interdisciplinary collaboration among VR, game design, architecture, and fandom studies, underscoring the inextricable link among ethics, ontology, and epistemology, culminating in a proposed ethico-onto-epistem-ological framework

    Organization based multiagent architecture for distributed environments

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    [EN]Distributed environments represent a complex field in which applied solutions should be flexible and include significant adaptation capabilities. These environments are related to problems where multiple users and devices may interact, and where simple and local solutions could possibly generate good results, but may not be effective with regards to use and interaction. There are many techniques that can be employed to face this kind of problems, from CORBA to multi-agent systems, passing by web-services and SOA, among others. All those methodologies have their advantages and disadvantages that are properly analyzed in this documents, to finally explain the new architecture presented as a solution for distributed environment problems. The new architecture for solving complex solutions in distributed environments presented here is called OBaMADE: Organization Based Multiagent Architecture for Distributed Environments. It is a multiagent architecture based on the organizations of agents paradigm, where the agents in the architecture are structured into organizations to improve their organizational capabilities. The reasoning power of the architecture is based on the Case-Based Reasoning methology, being implemented in a internal organization that uses agents to create services to solve the external request made by the users. The OBaMADE architecture has been successfully applied to two different case studies where its prediction capabilities have been properly checked. Those case studies have showed optimistic results and, being complex systems, have demonstrated the abstraction and generalizations capabilities of the architecture. Nevertheless OBaMADE is intended to be able to solve much other kind of problems in distributed environments scenarios. It should be applied to other varieties of situations and to other knowledge fields to fully develop its potencial.[ES]Los entornos distribuidos representan un campo de conocimiento complejo en el que las soluciones a aplicar deben ser flexibles y deben contar con gran capacidad de adaptación. Este tipo de entornos está normalmente relacionado con problemas donde varios usuarios y dispositivos entran en juego. Para solucionar dichos problemas, pueden utilizarse sistemas locales que, aunque ofrezcan buenos resultados en términos de calidad de los mismos, no son tan efectivos en cuanto a la interacción y posibilidades de uso. Existen múltiples técnicas que pueden ser empleadas para resolver este tipo de problemas, desde CORBA a sistemas multiagente, pasando por servicios web y SOA, entre otros. Todas estas mitologías tienen sus ventajas e inconvenientes, que se analizan en este documento, para explicar, finalmente, la nueva arquitectura presentada como una solución para los problemas generados en entornos distribuidos. La nueva arquitectura aquí se llama OBaMADE, que es el acrónimo del inglés Organization Based Multiagent Architecture for Distributed Environments (Arquitectura Multiagente Basada en Organizaciones para Entornos Distribuidos). Se trata de una arquitectura multiagente basasa en el paradigma de las organizaciones de agente, donde los agentes que forman parte de la arquitectura se estructuran en organizaciones para mejorar sus capacidades organizativas. La capacidad de razonamiento de la arquitectura está basada en la metodología de razonamiento basado en casos, que se ha implementado en una de las organizaciones internas de la arquitectura por medio de agentes que crean servicios que responden a las solicitudes externas de los usuarios. La arquitectura OBaMADE se ha aplicado de forma exitosa a dos casos de estudio diferentes, en los que se han demostrado sus capacidades predictivas. Aplicando OBaMADE a estos casos de estudio se han obtenido resultados esperanzadores y, al ser sistemas complejos, se han demostrado las capacidades tanto de abstracción como de generalización de la arquitectura presentada. Sin embargo, esta arquitectura está diseñada para poder ser aplicada a más tipo de problemas de entornos distribuidos. Debe ser aplicada a más variadas situaciones y a otros campos de conocimiento para desarrollar completamente el potencial de esta arquitectura

    Nineteenth International Cosmic Ray Conference. Conference Papers: Invited Rapporteur, Highlight, Miscellaneous, Volume 9

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    Invited talks, rapporteur talks, and highlight talks are included. Topics of the invited and highlight talks include astrophysical jets, gamma-ray line astronomy, cosmic rays and gamma rays in astrophysics, the early universe, elementary particle physics, solar flares and acceleration of energetic particles, cosmogenic nuclei, extragalactic astronomy, composition of solar flare particles, very high energy gamma ray sources, gamma-ray bursts, shock acceleration in the solar wind, cosmic rays in deep underground detectors, spectrum of cosmic rays at 10 to the 19th power eV, and nucleus-nucleus interactions
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