The author proposes a mechanism called the priority token bank for admission control, scheduling, and policing in integrated-services networks, where arrival processes and performance objectives can vary greatly from ...
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The author proposes a mechanism called the priority token bank for admission control, scheduling, and policing in integrated-services networks, where arrival processes and performance objectives can vary greatly from one packet stream to another. There are two principal components to the priority token bank: accepting or rejecting requests to admit entire packet streams, where acceptance means guaranteeing that the packet stream's performance objectives will be met, and scheduling the transmission of packets such that performance objectives are met, even under heavy loads. To the extent possible, the performance of traffic is also optimized beyond the requirements. The performance achieved with the priority token bank is compared to that of other typical algorithms. It is shown that, when operating under the constraint that the performance objectives of applications such as packet voice, HDTV (high-definition television) and bulk data transfer must be met in an ATM (asynchronous transfer mode) network, the mean delay experienced by other traffic is much better with the priority token bank. Equivalently, to achieve the same performance with other algorithms, it would be necessary to greatly reduce the network load.< >
This paper presents the development of a PC-based software package for the analysis of hourly electric loads, called GLAS (Graphic Load Analysis System). First, a description and comments on the usage of the various m...
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We consider the significant work in both the human-computer interaction and artificial intelligence fields in the area of intelligent interfaces, placing into a structure the disparate strands of research work. We tre...
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This paper suggests a method of control system parameter selection based on a set of parametric plots of closed-loop system performance. Here, the performance measures of rise time, settling time, percent overshoot, r...
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This paper suggests a method of control system parameter selection based on a set of parametric plots of closed-loop system performance. Here, the performance measures of rise time, settling time, percent overshoot, root sensitivity, gain margin, and phase margin are investigated as functions of the forward loop gain. The explicit functional dependence of these performance indices is summarized in plots that highlight the control system design space as well as the tradeoffs between feasible system parameters. An example problem demonstrates how the information serves as an aid in satisfying design specifications and uncovering design tradeoffs.
Artificial neural networks are employed for demodulation of spread-spectrum signals in a multiple-access environment. This paper is motivated in large part by the fact that, in a multiuser system, the conventional (ma...
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Artificial neural networks are employed for demodulation of spread-spectrum signals in a multiple-access environment. This paper is motivated in large part by the fact that, in a multiuser system, the conventional (matched filter) receiver suffers sever performance degradation as the relative powers of the interfering signals become large (the "near-far" problem). Furthermore, in many cases the optimum receiver, which alleviates the near-far problem, is too complex to be of practical use. Two simple structures employing multilayer perceptrons are proposed for demodulation of spread-spectrum signals in both synchronous and asynchronous Gaussian channels. The optimum receiver is used to benchmark the performance of the proposed receiver;in particular, it is proven to be instrumental in identifying the decision regions for the neural networks. The neural networks are trained for the demodulation of signals via back-propagation type algorithms. In particular, a modified back-propagation algorithm is introduced for single-user and multiuser detection with near-optimum performance that could have applications in other classification and pattern recognition problems. A comparative performance analysis of the three receivers, optimum, conventional and the one employing neural networks, is carried out via Monte Carlo simulations. An importance sampling technique is employed to reduce the number of simulations necessary to evaluate the performance of these receivers in a multiuser environment. In all examples considered, the proposed neural net receiver significantly outperforms the conventional receiver.
Family caregivers of dementia patients experience varying levels of burden (or stress) associated with care giving tasks. Although this burden may lead to negative health effects for caregivers, very few studies have ...
Sacks & Doyle provide an excellent overview of the fundamental limitations of the SPQR representations for reasoning about the qualitative properties of dynamic systems. We take this opportunity to outline some ne...
Sacks & Doyle provide an excellent overview of the fundamental limitations of the SPQR representations for reasoning about the qualitative properties of dynamic systems. We take this opportunity to outline some new directions for qualitative reasoning. In this paper, we provide a rigorous mathematical characterization for the term “qualitative property” in the context of static and dynamic systems. Based on these characterizations, we show that interval representations are well suited for reasoning about the qualitative properties of static systems such as qualitative comparative statics and qualitative stability. Moreover, we also show that symbolic computations help in the derivation of useful global properties of dynamic systems which can be used to guide numerical sampling of differential equations. The integration of symbolic and numeric methods provides a powerful approach for automating the qualitative analysis of differential equations.
The buildup of so-called "greenhouse gases" in the atmosphere - CO2 in particular-appears to be having an adverse impact on the global climate. This paper briefly reviews current expectations with regard to ...
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The buildup of so-called "greenhouse gases" in the atmosphere - CO2 in particular-appears to be having an adverse impact on the global climate. This paper briefly reviews current expectations with regard to physical and biological effects, their potential costs to society, and likely costs of abatement. For a "worst case" scenario it is impossible to assess, in economic terms, the full range of possible non-linear synergistic effects. In the "most favorable" (although not necessarily "likely") case (of slow-paced climate change), however, it seems likely that the impacts are within the "affordable" range, at least in the industrialized countries of the world. In the "third world" the notion of affordability is of doubtful relevance, making the problem of quantitative evaluation almost impossible. We tentatively assess the lower limit of quantifiable climate-induced damages at $30 to $35 per ton of "CO2 equivalent", worldwide, with the major damages being concentrated in regions most adversely affected by sea-level rise. The non-quantifiable environmental damages are also significant and should by no means be disregarded. The costs and benefits of (1) reducing CFC use and (2) reducing fossil fuel consumption, as a means of abatement, are considered in some detail. This strategy has remarkably high indirect benefits in terms of reduced air pollution damage and even direct cost savings to consumers. The indirect benefits of reduced air pollution and its associated health and environmental effects from fossil-fuel combustion in the industrialized countries range from $20 to $60 per ton of CO2 eliminated. In addition, there is good evidence that modest (e.g. 25%) reductions in CO2 emissions may be achievable by the U.S. (and, by implication, for other countries) by a combination of increased energy efficiency and restructuring that would permit simultaneous direct economic benefits (savings) to energy consumers of the order of
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