The AURORA Gigabit Testbed

AURORA is one of five U.S. networking testbeds charged with exploring applications of, and technologies necessary for, networks operating at gigabit per second or higher bandwidths. The emphasis of the AURORA testbed, distinct from the other four testbeds, BLANCA, CASA, NECTAR, and VISTANET, is research into the supporting technologies for gigabit networking. Like the other testbeds, AURORA itself is an experiment in collaboration, where government initiative (in the form of the Corporation for National Research Initiatives, which is funded by DARPA and the National Science Foundation) has spurred interaction among pre-existing centers of excellence in industry, academia, and government. AURORA has been charged with research into networking technologies that will underpin future high-speed networks. This paper provides an overview of the goals and methodologies employed in AURORA, and points to some preliminary results from our first year of research, ranging from analytic results to experimental prototype hardware. This paper enunciates our targets, which include new software architectures, network abstractions, and hardware technologies, as well as applications for our work

NORTH DAKOTA SHOPPER PERCEPTIONS OF GENETICALLY MODIFIED ORGANISMS AND FOOD: RESULTS OF A WINTER 2003 SURVEY

Replaced with revised version of paper 07/23/04.Biotechnology, Genetic Modification, Consumer Preferences, Food Consumption/Nutrition/Food Safety, Research and Development/Tech Change/Emerging Technologies,

On the distribution function of the information speed in computer network

We review a study of the Internet traffic properties. We analyze under what conditions the reported results could be reproduced. Relations of results of passive measurements and those of modelling are also discussed. An example of the first-order phase transitions in the Internet traffic is presented.Comment: cpcauth.cls included, 6 pages, 3 eps figures, Proceeding CCP 2001 Aachen, to appear in Comp. Phys. Com

The Integrated Media Approach to Networked Multimedia Systems

Applications which require real-time multimedia services[13] face a number of difficult problems in the transmission of multimedia information. Among the most difficult problems are the heterogeneity of end nodes and the heterogeneity of media Quality of Service (QoS) requirements. End nodes typically consist of a computer and number of sensory input and output devices, such as displays, microphones, and cameras. QoS requirements[18] include degrees of reliability, jitter, and delay. We propose an integrated approach to address these problems. Multimedia input data comprise a sensory environment which an application will make available; these data are packaged together into an Integrated Multimedia Message (IMM). From a received IMM, output data are selectively reproduced to create another sensory environment. We propose an IMM format and protocol behaviors for generation, presentation, and synchronization of these messages. While IMM\u27s are aesthetically pleasing, well-suited to proposed high- speed networks, and ease intramessage synchronization, they are potentially plagued by the need to deliver QoS which meets the worst-case requirements of all of their components[6]. We believe that this problem can be addressed, and are testing that belief experimentally with the U. Penn Experimental Multimedia Conferencing System, which will be embedded in the AURORA Gigabit Testbed

Reliability study on avionics: feasibility study to determine mean time between failure (MTBF)

In general, the world faces an increase in the pressure to perform faster, better and cheaper, requiring engineers to predict accurately the reliability of products. In the early stages of the design process, these accurate predictions will contribute not only to a more robust and reliable product, but also will drive down the costs associated with redesigning the equipment/component, for example, when a product is already in production and a design error is found or as the result to improve the reliability obtained from operation. The number of electronic components, equipment and systems in an airplane increases with the new developments in technology. That is why it is imperative that manufacturer predict the failure rate and the mean time between failure of each equipment/component with the greatest accuracy. For this accuracy to be fulfilled, there are three methodologies: empirical (based on standards), failure mechanisms, and accelerated/life tests. The most common methodology is the use of standards. The main handbook/standard used in the electronics industry for the prediction of the mean time between failure is the MIL-HDBK-217F. However, at the present moment of technology development, this handbook is obsolete, as the predicted values are far from the reality. To overcome this problem, several companies from aeronautic and aerospace sector developed a standard called FIDES, which incorporate the three methodologies so that there was a significant improvement in predicting the probability of systems failure. By the fact that this standard is updated periodically and revised, it makes it one of the most suitable and accurate methods of predicting the probability of failure and mean time between failure for recent technologies. Therefore, this dissertation is based on this standard, using the methodology described alongside with the information and data retrieved in collaboration with Aeromec, for calculating the mean time between failure of electronic components, four integrated circuits. The final aim of this study is to establish a methodology to predict the mean time between failure of a specific component, giving to Aeromec a relevant process, namely the methodology implemented, to do the calculations for the equipment to be fitted on to an aircraft, and if feasible, then make adjustments to the aircraft maintenance programs under their responsibility The comparison of the results obtained was carried out by comparing it with an estimated value for the mean time between failure of the four integrated circuits done by Flight Data Systems with the “ReliaSoft” reliability prediction software. With this study it was found that the prediction of the mean time between failure for the four integrated circuits, carried out using the FIDES standard, is more optimistic and therefore with a longer/higher mean time between failure then the prediction made by Flight Data Systems with the MIL-HDBK-217F standard. This may be due to two factors: the MIL-HDBK-217F standard has not been reviewed and updated for new technologies since 1995, contrary to the FIDES standard; and the usage profile in Flight Data Systems prediction does not exactly match as the one in FIDES. For future works, the next step is to conduct a full study to assess the mean time between failure for a specific equipment, for example a primary flight display that has several different components, meaning estimate the mean time between failure for every component incorporated, and then the overall mean time between failure. This work could be done by Aeromec to assess the mean time between failure for the equipment that will be installed in to aircraft in maintenance.No momento presente o mundo enfrenta um aumento na pressão para que os trabalhos se executem de modo mais rápido, melhor e mais barato, exigindo que os engenheiros prevejam com precisão a fiabilidade dos produtos. Nas fases iniciais do processo de design do produto, essas previsões precisas contribuirão não só para um produto mais robusto e fiável, mas também reduzirão os custos associados a redesenhar o produto, por exemplo, quando o produto está em fase de manufatura e é encontrado um erro de design, ou face a necessidade de melhorar a fiabilidade detetada em sede de utilização. O número de componentes eletrónicos, equipamentos e sistemas numa aeronave, aumenta com os novos avanços na tecnologia. Por isso é imperativo que os fabricantes destes mesmos equipamentos eletrónicos prevejam com exatidão a probabilidade de falha e o tempo médio entre falhas de cada equipamento/componente. Para que esta exatidão seja elevada, existem três metodologias: empírica (baseada em standards), mecanismos de falha, e testes acelerados. A metodologia mais comum é a utilização de standards. Um dos primeiros standard desenvolvidos e mais reconhecido, principalmente na área militar, é o MIL-HDBK-217F, contudo no momento presente de desenvolvimento da tecnologia, encontra-se obsoleto, pois os valores de previsão são aquém da realidade. Para ultrapassar este problema, um consórcio de empresas da área de aeronáutica e aeroespacial desenvolveu o standard FIDES, agrupando as três metodologias para que houvesse uma melhoria significativa na previsão da probabilidade de falha de sistemas. Pelo facto de o standard FIDES ser periodicamente atualizado e revisto, faz deste um dos standards mais adaptados e precisos na previsão da probabilidade de falha e tempo médio entre falhas para tecnologias recentes. Assim sendo, esta dissertação tem por base o standard FIDES, conjugando a metodologia descrita para o cálculo da probabilidade de falha de componentes eletrónicos com a informação e dados recolhidos em colaboração com a empresa de manutenção Aeromec, para a realização do estudo do tempo médio entre falhas em quatro circuitos integrados. O objetivo final deste estudo é estabelecer uma metodologia que permita determinar o tempo médio entre falhas de um componente específico, fornecendo à empresa de manutenção Aeromec um processo relevante, nomeadamente a metodologia implementada, para o cálculo do tempo médio entre falhas dos equipamentos a serem instalados, e, se viável, permitir fazer ajustes aos programas de manutenção das aeronaves sob sua responsabilidade. A comparação dos resultados obtidos foi realizada através da comparação com um valor estimado para o tempo médio entre falhas dos circuitos integrados estudados por parte da empresa Flight Data Systems com o software para previsão do tempo médio entre falhas, denominado “ReliaSoft”. Com este estudo verificou-se que a previsão do tempo médio entre falhas para os quatro circuitos integrados, realizada recorrendo ao standard FIDES, é mais otimista e portanto com um tempo médio entre falhas mais longo do que o standard MIL-HDBK217F, utilizado para a mesma previsão por parte da empresa Flight Data Systems. Podendo isto dever-se a dois fatores: o standard MIL-HDBK-217F não ser revisto e atualizado para as novas tecnologias desde 1995, contrariamente ao standard FIDES; O perfil de utilização da previsão por parte da empresa Flight Data Systems não corresponder exatamente ao perfil de utilização no estudo. Em trabalhos futuros, o próximo passo será conduzir um estudo do tempo médio entre falhas para um equipamento específico, por exemplo um display primário de voo, recorrendo a metodologia apresentada neste estudo, estimando o tempo médio de falhas de cada componente incorporado no equipamento, para posterior cálculo do tempo médio entre falhas total. Este trabalho poderá ser realizado por parte da Aeromec para avaliar o tempo médio entre falhas para equipamentos a serem instalados em aeronaves a realizar manutenção

The Register, 1996-02-14

https://digital.library.ncat.edu/atregister/2198/thumbnail.jp