A theoretical model of microwave absorption in linear dielectric (non-ferroelectric) ionic crystals that takes into account the presence of point defects was synthesized and verified using NaCl single crystals. In the...
A theoretical model of microwave absorption in linear dielectric (non-ferroelectric) ionic crystals that takes into account the presence of point defects was synthesized and verified using NaCl single crystals. In the next stage of this research, we will introduce a controlled density of dislocations into the single crystal NaCl samples and study the effect on the microwave absorption mechanisms (ionic conduction, dielectric relaxation and multi-phonon processes) both theoretically and experimentally. Qualitative outlines of this modified theory are presented. The loss factor ε’ has been measured in the dislocation-free case by a cavity resonator insertion technique and the experimental results are in good agreement with the theoretical model. We describe the sample preparation technique that will be used to produce a controlled dislocation density in single crystal samples that will also be studied in our cavity resonator insertion system.
An analytic model for the performance evaluation of space-division Asynchronous Transfer Mode (ATM) switches is presented. This model assumes that the switch has a fixed capacity of m, where 12 is given. The result sh...
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We contribute to the debate about the relation between software design and standard engineering design. We do this by examining the approaches taken by both disciplines to the design of a small embedded system. The ex...
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We contribute to the debate about the relation between software design and standard engineering design. We do this by examining the approaches taken by both disciplines to the design of a small embedded system. The example chosen is that of an automotive cruise control system whose design is described in both computing and automotive literature. We do not attempt to argue that software development should be more like other engineering disciplines nor do we support the argument that software development is too complex or different in nature to be compared to traditional engineering.
Processing conditions such as temperature, soak time, and heating rate affect the final density of conventionally-sintered and microwave-sintered ceramics. Of additional importance is the question of whether microwave...
Processing conditions such as temperature, soak time, and heating rate affect the final density of conventionally-sintered and microwave-sintered ceramics. Of additional importance is the question of whether microwave-sintered ceramics display intrinsically superior macroscopic engineering properties compared with conventionally-sintered control specimens. An analysis using the Yates algorithm indicates that the processing condition which has the largest impact on the density of the specimen is the heating method (microwave vs. conventional). The microwave-sintered specimens resulted in higher densities and higher fracture strengths. However, it was determined that the higher fracture strengths were due to the higher sintered densities rather than a significantly different microstructure.
Body surface Laplacian maps were studied from a set of unipolar potential data in healthy human subjects. The present results indicate that body surface Laplacian maps can be obtained with high reproducibility in the ...
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Body surface Laplacian maps were studied from a set of unipolar potential data in healthy human subjects. The present results indicate that body surface Laplacian maps can be obtained with high reproducibility in the human subjects studied, and can reveal detailed information regarding the underlying ventricular conduction process.
The authors have developed a multi-purpose X-window based mapping software system. This software system can be used to analyze and display body surface maps of the Laplacian electrocardiogram, potential electrocardiog...
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The authors have developed a multi-purpose X-window based mapping software system. This software system can be used to analyze and display body surface maps of the Laplacian electrocardiogram, potential electrocardiogram, electroencephalogram, etc.
An analytic model for the performance evaluation of space-division asynchronous transfer mode (ATM) switches is presented. This model assumes that the switch has a fixed capacity of m, where 1/spl les/m/spl les/N (N i...
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An analytic model for the performance evaluation of space-division asynchronous transfer mode (ATM) switches is presented. This model assumes that the switch has a fixed capacity of m, where 1/spl les/m/spl les/N (N is the number of trunks). Other important parameters include arrival rate and buffer sizes. Numerical solutions for the maximum throughput, cell delay, and cell loss probability are given with simulation being utilized in order to validate the analytic model. For independent and identical Bernoulli arrivals, the study shows that the contention processes can be modeled as discrete M/D/m (FIFO or Random) queues, while input queues can be modeled by Geom/G/1 queues, and the output queues are G/sup [X]//D/1 queues. A closed-form approximation for cell delay when m>2 is given. The result shows that the performance of switches with a small capacity can approach that of output queueing. The model and result can be used for switch design analysis and higher layer performance models.
The advantages of single electron device with asymmetrical tunnel barriers (ATBs), proposed by the authors((1)), over conventional single electron device with symmetrical tunnel barriers (STBs) are discussed referring...
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ISBN:
(纸本)0780333942
The advantages of single electron device with asymmetrical tunnel barriers (ATBs), proposed by the authors((1)), over conventional single electron device with symmetrical tunnel barriers (STBs) are discussed referring the features of ATBs and the results of computer simulation of the performance of tunnel-junction-load SET logic and turnstile devices. Experimental observation of Coulomb staircase and asymmetrical tunnel characteristic in ATBs fabricated with GaAs/AlGaAs heterostructure is also reported.
This paper describes a market driven life cycle methodology for application of off-the-shelf products and provides anecdotal lessons for each of the life cycle phases. In order to form a framework for further discussi...
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This paper describes a market driven life cycle methodology for application of off-the-shelf products and provides anecdotal lessons for each of the life cycle phases. In order to form a framework for further discussion, a model of the off-the-shelf marketplace is introduced to define a range of products from low cost commodities to high-end niche or specialty items. Within this framework, strategies are recommended for defining product requirements both technical and programmatic, surveying the market to find products that meet those requirements and then acceptance testing those products to ensure they do in fact perform as advertised. Recommendations are provided in the area of product tailoring, if tailoring is deemed a cost effective alternative to unique design. The pitfalls of managing ''off-the-shelf'' vendors as subcontractors during the tailoring phase is also described. Product procurement is defined to include not only those steps required to procure product quantities for deploy ment but also steps to ensure that those products meet the same requirements as those accepted during the selection phase. Three product support strategies are next described. The strategies range from a traditional ''commercial'' approach with support provided within the vendor's infrastructure to a more traditional ''military'' approach in which vendors are subcontracted to provide longer term support. Selection of the appropriate strategy is based on a balance of cost, desired product life and desired level of stability within the system configuration.
The study proposes a combination of the function points model for software estimation with the ADISSA methodology for systems analysis and design. This combined approach, which is supported by a software tool, enables...
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The study proposes a combination of the function points model for software estimation with the ADISSA methodology for systems analysis and design. This combined approach, which is supported by a software tool, enables one to estimate various software metrics, such as size, effort, and duration, in the early stages of systems development, by basing them on the products of a thorough system analysis and design process.
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