The ultimate goal in the manufacturing of a part is to achieve an economic production plan with precision and accuracy in the first attempt at machining. A physics-based comprehensive modeling of the machining processes is a fundamental requirement in identifying optimal cutting conditions which result in high productivity rates without violating accuracy throughout the part production process. This thesis presents generalized virtual simulation and optimization strategies to predict and optimize performance of milling processes up to 3-axis. Computationally efficient mathematical models are introduced to predict milling process state variables such as chip load, force, torque, and cutting edge engagement at discrete cutter locations. Process states are expressed explicitly as a function of helical cutting edge - part engagement, cutting coefficient and feedrate. Cutters with arbitrary geometries are modeled parametrically, and the intersection of helical cutting edges with workpiece features are evaluated either analytically or numerically depending on geometric complexity. The dynamics of generalized milling operations are modeled and the stability of the process is predicted using both time and frequency domain based models. These algorithms enable rapid simulation of milling operations in a virtual environment as the part features vary. In an effort to reduce machining time, a constraint-based optimization scheme is proposed to maximize the material removal rate by optimally selecting the depth of cut, width of cut, spindle speed and feedrate. A variety of user defined constraints such as maximum tool deflection, torque/power demand, and chatter stability are taken into consideration. Two alternative optimization strategies are presented: pre-process optimization provides allowable depth and width of cut during part programming at the computer aided manufacturing stage using chatter constraint, whereas the post-process optimization tunes only feedrate and spindle speed of an existing part program to maximize productivity without violating physical constraints of the process. Optimized feedrates are filtered by considering machine tool axes limitations and the algorithms are tested in machining various industrial parts. The thesis contributed to the development of a novel 3-axis Virtual Milling System that has been deployed to the manufacturing industry.

Increasingly, knowledge-based tasks such as new product development and market research are being conducted by geographically dispersed teams. Early evidence from knowledge-based view of the firm and geographically dispersed work literatures suggests that at least four kinds of knowledge gaps---transactive memory system, mutual knowledge, categorization and situated knowledge---exist because of the (dispersed) structure of the knowledge management context . Dispersed members therefore cannot take for granted that they have a common context, making dispersed collaboration problematic. / The dissertation - a qualitative, theory-generating exercise - seeks to address the question, 'how do dispersed teams collaborate to create useful knowledge?' Specifically, the research question examines the integral elements of the knowledge creation process, the negotiation of knowledge gaps for co-creating a common context, and the association between the negotiation of these gaps with the efficiency of the knowledge creation process, effectiveness of new knowledge created, and cohesion in the team. This research has been conducted in two phases - an exploratory ethnographic study followed by a replication study. / Analysis of the data instead directed my attention to the critical role of moderating variables such as degree of familiarity among dispersed team members, degree of redundancy of knowledge structures among them and the nature of task on the perceived presence or absence of gaps. These findings clarify the literature by differentiating between the structure and the properties of the knowledge management context and therefore develop a more comprehensive model of these moderating variables that have the potential to affect the dispersed knowledge creation process. Specifically, the findings demonstrate that degree of redundancy is positively associated with the efficiency of the knowledge creation process. These studies also suggest that dispersed collaboration may be less different from collocated collaboration than previously thought. Finally, these studies contribute to the dispersed work literature by suggesting that all kinds of dispersed work are not alike and face-to-face meetings may not be necessary for all types of dispersed work. / These findings are used to develop a theory of dispersed knowledge work and have implications for determining whether and in what contexts geographic distance matters for conducting knowledge work. One implication is that perceptions of distance may be at least as important as the objective aspects of distance. Another implication is that whether geographic distance matters will actually depend upon the competitive strategy of the firm.

Virtual reality has existed for many years, dating back to the 1940s but becoming popular on a larger scale in the late 1980s and early 1990s. It has been largely regarded as something of a plaything or hobby and, in general, as something that is on a lower echelon when compared to physical reality. In recent years, however, as our society becomes more interconnected via the Internet and as highly interactive web services, such as Facebook, Second Life, and Twitter, play a larger role in individualsʼ lives, a reexamination of the status of virtual reality becomes necessary. ! This study employs the work of a major twentieth century critic, Kenneth Burke, and from his conception of dramatism to demonstrate that 1) virtual reality, for many, is a significant reality that can often lead to the formation of meaningful relationships between individuals and 2) the significance of this reality is born out of users dramatizing their online experiences. Through heuristics and dramatistic analysis, I examine how the users of Facebook dramatize their actions and collectively contribute to the formation of a controlling narrative that can be seen across all of virtual reality. Further, the findings of this thesis provide a heuristic foundation for future research into virtual reality. / The problem -- Literature review -- Method -- The controlling drama of Facebook as a virtual reality -- Conclusions, limitations and heuristic propositions. / Department of Telecommunications

Interest in the area of virtual work continues to increase with articles being written from different disciplinary perspectives - e.g. information systems (IS), management, psychology and transportation. In this paper, we map research on virtual work to (a) understand the intellectual base from which this field has emerged, (b) explore how this field has evolved over time, and (c) identify clusters of research themes that have emerged over time and the relationships between them. Specifically, we use co-citation analysis of research published in all social science disciplines to map the field at three points in time - 1995, 2000 and 2006. Our results show that the field has grown from nine research clusters in 1995 to sixteen in 2006. A comparison across these maps suggests that research in the cluster of "virtual teams" has gained significance even as research within some earlier clusters such as "urban planning and transportation" has lost ground. Our longitudinal analysis identifies relevant concepts, theories and methodologies that have emerged in the field of virtual work. This analysis can help interested researchers identify how they may want to contribute to the field of virtual work - by adding to popular clusters, enriching emerging smaller clusters or by acting as bridges across clusters. (author's abstract)

The ultimate goal in the manufacturing of a part is to achieve an economic production plan with precision and accuracy in the first attempt at machining. A physics-based comprehensive modeling of the machining processes is a fundamental requirement in identifying optimal cutting conditions which result in high productivity rates without violating accuracy throughout the part production process. This thesis presents generalized virtual simulation and optimization strategies to predict and optimize performance of milling processes up to 3-axis. Computationally efficient mathematical models are introduced to predict milling process state variables such as chip load, force, torque, and cutting edge engagement at discrete cutter locations. Process states are expressed explicitly as a function of helical cutting edge - part engagement, cutting coefficient and feedrate. Cutters with arbitrary geometries are modeled parametrically, and the intersection of helical cutting edges with workpiece features are evaluated either analytically or numerically depending on geometric complexity. The dynamics of generalized milling operations are modeled and the stability of the process is predicted using both time and frequency domain based models. These algorithms enable rapid simulation of milling operations in a virtual environment as the part features vary. In an effort to reduce machining time, a constraint-based optimization scheme is proposed to maximize the material removal rate by optimally selecting the depth of cut, width of cut, spindle speed and feedrate. A variety of user defined constraints such as maximum tool deflection, torque/power demand, and chatter stability are taken into consideration. Two alternative optimization strategies are presented: pre-process optimization provides allowable depth and width of cut during part programming at the computer aided manufacturing stage using chatter constraint, whereas the post-process optimization tunes only feedrate and spindle speed of an existing part program to maximize productivity without violating physical constraints of the process. Optimized feedrates are filtered by considering machine tool axes limitations and the algorithms are tested in machining various industrial parts. The thesis contributed to the development of a novel 3-axis Virtual Milling System that has been deployed to the manufacturing industry.

Thesis (Ph. D.)--Miami University, Dept. of Psychology, 2006. / Title from second page of PDF document. Includes bibliographical references (p. 64-72).

Made available in DSpace on 2014-06-11T19:26:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-17Bitstream added on 2014-06-13T19:34:38Z : No. of bitstreams: 1 voltan_ds_me_botfca.pdf: 1188116 bytes, checksum: 733960c94727811d00be0fc1909716fa (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / O objetivo deste trabalho foi o desenvolvimento de um sistema computacional para o sensoriamento, aquisição de dados e visualização de parâmetros físicos, fundamentais para a área de irrigação. O trabalho incluiu aspectos de hardware e software, e foi desenvolvido utilizando a plataforma de instrumentação virtual chamada LabVIEW, composta por uma placa de hardware padrão para aquisição de dados e de um ambiente para desenvolvimento de softwares. Durante o desenvolvimento, sensores foram conectados ao hardware do LabVIEW para a medição de três parâmetros físicos importantes para a irrigação, que são temperatura ambiente, umidade relativa do ar e índice pluviométrico. Paralelamente, foram desenvolvidos os softwares, em ambiente LabVIEW, responsáveis pela aquisição de dados dos sensores e pela interface homem-máquina de comunicação com o usuário, permitindo a visualização e interpretação dos dados agrometeorológicos em tempo-real e de forma simples, a fim de que possam ser eficientemente analisados por um usuário sem treinamentos prévios. O trabalho também incluiu o desenvolvimento de mecanismos de hardware para a análise das características físicas dos sensores de temperatura, umidade e de precipitação, permitindo a verificação de parâmetros como precisão, exatidão, ruído elétrico, etc. Isto representou um tópico adicional ao trabalho, o qual apresenta um produto para a análise de confiabilidade e desempenho dos sensores para aplicações agrícolas. Além disso, nesse trabalho foi desenvolvido um software genérico que permite a aquisição de dados de qualquer dispositivo de sensoriamento que tenha saída de dados no padrão de comunicação serial RS-232, os quais são atualmente muito utilizados em diversos dispositivos de sensoriamento. Na análise dos resultados, o trabalho permitiu o desenvolvimento de um sistema eficiente de análise... / The aim of this study was to develop a computer system for sensing, data acquisition and visualization of physical parameters that are fundamental to the irrigation area. The work included aspects of hardware and software, thus it was developed using the virtual instrumentation platform called LabVIEW that consisting of a standard hardware interface for data acquisition and a software development environment. During development, the sensors were connected to the LabVIEW hardware for measurement of three main physical parameters for irrigation, which are temperature, relative humidity and rainfall. In parallel, four pieces of software were developed in the LabVIEW environment, which were responsible for data acquisition from sensors and for the human-machine interface, allowing the visualization and interpretation of agrometeorological data in real-time and with a friendly environment that can be efficiently analyzed by a user without prior training. The work also included the development of hardware mechanisms for the analysis of physical characteristics of temperature sensors, humidity and precipitation, allowing verification of parameters such as precision, accuracy, noise, etc. This represented an additional topic to the work, introducing a product for the reliability and performance analyses of the sensors in agricultural applications. In addition, to this work was developed generic software that allows data acquisition of any sensing device which outputs data in the standard RS 232 serial communication, which are widely used in various sensing devices. The result includes a system that allows efficient sensor parameters analysis, performs the data acquisition and also allows a friendly visual interaction with user. Thus, we conclude that the initial objectives were achieved, which it is important to note that... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:24:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-30Bitstream added on 2014-06-13T20:12:04Z : No. of bitstreams: 1 gasperini_r_me_bauru.pdf: 2885899 bytes, checksum: ba50db0f1568ced891c92f809e88edf8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A ergonomia está cada vez mais presente no desenvolvimento do produto e consequentemente no processo produtivo. As empresas estão sentindo que o investimento em ergonomia é de suma importância na preservação da saúde de seus colaboradores como também no aumento de eficiência da produtividade. Para isso algumas empresas investem em alta tecnologia como Centros de Realidades Virtuais para simular e prever atividades futuras e desenvolver novos produtos. Esta ferramenta utilizada pelas indústrias busca antecipar a melhor solução para os postos de trabalho tornando as atividades menos desgastantes e penosas como também tornando os produtos mais eficientes. Deste modo a pesquisa teve como objetivo avaliar a aplicação da realidade virtual imersiva na análise e avaliação ergonômica por meio do design participativo e assim conhecer suas potencialidades. Este estudo buscou verificar até que ponto a realidade virtual pode auxiliar os especialistas em ergonomia sem que os mesmos tenham que produzir modelos físicos. A metodologia empregada nesta pesquisa envolveu a utilização de um Centro de Realidade Virtual - CRV com o método de grupo de foco simulando atividades e captando a percepção dos sujeitos envolvidos. O experimento evidenciou grande relevância nas aplicações da realidade virtual em algumas situações como na análise de biomecânica, movimento simultâneo e percepção do usuário, porém em algumas atividades verificou-se a necessidade da construção de modelos físicos para maior interação e envolvimento do sujeito. Os testes efetuados também mostraram que a realidade virtual tornou possível a avaliação ergonômica de uma atividade que seria impossível de ser efetuada em ambiente real sem que houvesse uma grande alocação financeira. Este fato se deve pelo motivo da dimensão do produto estudado (grande proporção) e a complexidade do processo... / The ergonomics is even more present time in the development of the productive process. The companies feel that the investment in ergonomics is of utmost importance in the preservation of its collaborators health as well as in the increase of efficiency of the productivity. For this reason companies invest in high technology as Centers of Virtual Realities to simulate and to foresee future activities as well as to develop new products. This tool used by the industries searches to anticipate the best solution for the work place turning tough activities less tiring as well as making the products more efficient. In this way the research had as objective to evaluate the application of the immersed virtual reality in the analysis and ergonomic evaluation through the participatory design to know its potentialities. This study aimed verifies to what point the virtual reality can assist the specialists in ergonomics without producing physical models. The methodology used in this research involved the use of a Center of Virtual Reality - CVR with the method of group of focus simulationg some activities and catching the perception of the involved person. The experiment evidenced great relevance in the applications of the virtual reality in some situations as in the analysis of biomechanics and perception of the user, however in some activities it was verified the necessity of the construction of physical models for bigger interaction and involvement of the participants. The tests had also shown that the virtual reality became the ergonomic evaluation of an activity possible which would be impossible to be done in real environment without the necessity on financial allocation. This fact is due to the reason of the dimension of the studied product (great ratio) and the complexity of the process. The tool (Virtual Reality) also provided to try the involvement of the team through participatory design ... (Complete abstract click electronic access below)

Orientador: João Eduardo Machado Perea Martins / Banca: Rosemary Marques de A. Bertani / Banca: Marco Antonio Gandolfo / Resumo: O objetivo deste trabalho foi o desenvolvimento de um sistema computacional para o sensoriamento, aquisição de dados e visualização de parâmetros físicos, fundamentais para a área de irrigação. O trabalho incluiu aspectos de hardware e software, e foi desenvolvido utilizando a plataforma de instrumentação virtual chamada LabVIEW, composta por uma placa de hardware padrão para aquisição de dados e de um ambiente para desenvolvimento de softwares. Durante o desenvolvimento, sensores foram conectados ao hardware do LabVIEW para a medição de três parâmetros físicos importantes para a irrigação, que são temperatura ambiente, umidade relativa do ar e índice pluviométrico. Paralelamente, foram desenvolvidos os softwares, em ambiente LabVIEW, responsáveis pela aquisição de dados dos sensores e pela interface homem-máquina de comunicação com o usuário, permitindo a visualização e interpretação dos dados agrometeorológicos em tempo-real e de forma simples, a fim de que possam ser eficientemente analisados por um usuário sem treinamentos prévios. O trabalho também incluiu o desenvolvimento de mecanismos de hardware para a análise das características físicas dos sensores de temperatura, umidade e de precipitação, permitindo a verificação de parâmetros como precisão, exatidão, ruído elétrico, etc. Isto representou um tópico adicional ao trabalho, o qual apresenta um produto para a análise de confiabilidade e desempenho dos sensores para aplicações agrícolas. Além disso, nesse trabalho foi desenvolvido um software genérico que permite a aquisição de dados de qualquer dispositivo de sensoriamento que tenha saída de dados no padrão de comunicação serial RS-232, os quais são atualmente muito utilizados em diversos dispositivos de sensoriamento. Na análise dos resultados, o trabalho permitiu o desenvolvimento de um sistema eficiente de análise... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to develop a computer system for sensing, data acquisition and visualization of physical parameters that are fundamental to the irrigation area. The work included aspects of hardware and software, thus it was developed using the virtual instrumentation platform called LabVIEW that consisting of a standard hardware interface for data acquisition and a software development environment. During development, the sensors were connected to the LabVIEW hardware for measurement of three main physical parameters for irrigation, which are temperature, relative humidity and rainfall. In parallel, four pieces of software were developed in the LabVIEW environment, which were responsible for data acquisition from sensors and for the human-machine interface, allowing the visualization and interpretation of agrometeorological data in real-time and with a friendly environment that can be efficiently analyzed by a user without prior training. The work also included the development of hardware mechanisms for the analysis of physical characteristics of temperature sensors, humidity and precipitation, allowing verification of parameters such as precision, accuracy, noise, etc. This represented an additional topic to the work, introducing a product for the reliability and performance analyses of the sensors in agricultural applications. In addition, to this work was developed generic software that allows data acquisition of any sensing device which outputs data in the standard RS 232 serial communication, which are widely used in various sensing devices. The result includes a system that allows efficient sensor parameters analysis, performs the data acquisition and also allows a friendly visual interaction with user. Thus, we conclude that the initial objectives were achieved, which it is important to note that... (Complete abstract click electronic access below) / Mestre

Submitted by Paula Quirino (paula.quirino@ufpe.br) on 2015-03-05T17:21:13Z No. of bitstreams: 1 DISSERTAÇÃO Cleyton Leandro Galvão.pdf: 1118579 bytes, checksum: 2172d660509d7b1ca1ca09099647fe91 (MD5) / Made available in DSpace on 2015-03-05T17:21:13Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO Cleyton Leandro Galvão.pdf: 1118579 bytes, checksum: 2172d660509d7b1ca1ca09099647fe91 (MD5) Previous issue date: 2014 / O problema de Identidade Virtual é fruto da Revolução Informacional devido ao progresso das tecnologias da informação e comunicação. A Era da Informação promoveu o surgimento de uma esfera que abrange a biosfera e a ultrapassa: a Infosfera. O principal elemento promotor da Infosfera é a Internet. Ela dividi-se em três dimensões distintas, sendo a mais importante delas a dimensão do Ciberespaço. Neste espaço ocorre a fusão de diversas tecnologias digitais, destacando-se a Realidade Virtual. O mundo digital fundamenta-se em dados e informação. Este dois conceitos são o elo entre o mundo real e o virtual. O modo como o virtual e o real se funde é pela nossa capacidade de estender nossas mentes através de aparelhos não biológicos. Somos, portanto, ciborgues de nascença. A Identidade Virtual surge quando o contato com o mundo virtual através das tecnologias da informação cria perfis e avatares. A Identidade Virtual potencializa o ser humano, mergulhando-o na natureza própria da virtualidade.