In this paper the behavior of fixed series compensated EHV transmission lines during faults is simulated. Emphasis is given on the impact of modern capacitor protection techniques (metal oxide varistor protection). Th...
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In this paper the behavior of fixed series compensated EHV transmission lines during faults is simulated. Emphasis is given on the impact of modern capacitor protection techniques (metal oxide varistor protection). The simulation study is performed using EMTP and results are given for a three-phase and a two-phase to ground fault.
This paper presents analysis and evaluation of the environmental impacts of electricity interchanges between interconnected systems. Power interchanges affect the utilization of the individual generation systems and c...
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This paper presents analysis and evaluation of the environmental impacts of electricity interchanges between interconnected systems. Power interchanges affect the utilization of the individual generation systems and consequently the emissions by each system; it is anticipated that power interchanges have a different environmental impact for each system. The analysis is performed using two computer models developed at NTUA: PROSIM for probabilistic production simulation and POWEREX for scheduling the economic interchanges between the power systems. A complete study considering the power systems of Greece, and variants of the Italian and Bulgarian systems is presented in detail.
This paper illustrates the use of symbolic model checking in the design of deadlock-free flexible manufacturing systems. Our verification methodology consists of the following stages. First, we extract a state machine...
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This paper illustrates the use of symbolic model checking in the design of deadlock-free flexible manufacturing systems. Our verification methodology consists of the following stages. First, we extract a state machine model of the system. Second, we write the system specifications using a propositional temporal logic. Finally we use the model checker to check the state machine of the system against its requirements. When a deadlock is identified, a counterexample is automatically generated with a scenario that leads to the deadlock. The counterexample is used to design the proper operational policy that will prevent the corresponding deadlock. This verification approach allows an exhaustive search of all possible behaviors and scenarios. We designed a flexible manufacturing system capable of producing 3 types of parts with 4 machines and 3 robots. It took 8 seconds to find possible deadlocks assuming machine processing capacity of one part at a time and about 36 seconds when we increased the machine processing capacity to two parts at a time. The size of the state space was in the order of 10/sup 18/ states.
This paper describes a method based on self-feedback for controlling both chaotic and nonchaotic forms of the Hénon map with and without additive Gaussian white noise. We describe a nonlinear self-tuning controll...
This paper describes a method based on self-feedback for controlling both chaotic and nonchaotic forms of the Hénon map with and without additive Gaussian white noise. We describe a nonlinear self-tuning controller that makes use of a feedback reference signal and a linear autoregressive formulation for the gain. This controller is effective at stabilizing the map to a variety of fixed point or period-two orbits. We contrast our approach with the method of Ott, Grebogi, and Yorke [Phys. Rev. Lett. 64, 1196 (1990)] which has been used to control some chaotic processes and recently, some nonchaotic, stochastic ones.
This paper is part of an ongoing activity of the IEEE Application of Probability Methods Subcommittee to advance the probabilistic methods used to analyze Bulk Power System (BPS) reliability. The objective of the Task...
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This paper is part of an ongoing activity of the IEEE Application of Probability Methods Subcommittee to advance the probabilistic methods used to analyze Bulk Power System (BPS) reliability. The objective of the Task Force is to develop a set of guidelines for measuring delivery point reliability. This involves reviewing published literature and other documentation of existing procedures, definitions, and indices. This report presents the results of the Task Force efforts to compile a useful set of terms and procedures for consistent reporting of BPS delivery point reliability.
I WetBiIl is a business model, set of protocols, and software implementation for commerce in information goods and other network-delivered services. It has very low transaction costs for micropayments (around I cent f...
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I WetBiIl is a business model, set of protocols, and software implementation for commerce in information goods and other network-delivered services. It has very low transaction costs for micropayments (around I cent for a 10 cent item), protects the privacy of the transaction, and is highly scalable. Of special interest is our new certified delivery mechanism which delivers information goods if and only if the consumer has paid for them. This article discusses the design of the NetBill protocol and our World Wide Web (WWW) prototype implementation. As the explosive growth of the Internet continues, more people rely on networks for timely information. However, since most information on the Internet today is free, intellectual property owners have little incentive to make valuable information accessible through the network. There are many potential providers who could sell information on the Internet and many potential consumers for that information. What is missing is an electronic commerce mechanism that links the merchants and the consumers. NetBill is a business model, set of protocols, and software implementation allowing consumers to payowners and retailers of information. While NetBill will enable a market economy in information, we still expect that there will be an active exchange of free information.
Load analysis is one of the most important operations that support demand-side management in large electric utilities. Ordinary load analysis techniques stress on statistical processing of hourly load data along prede...
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Load analysis is one of the most important operations that support demand-side management in large electric utilities. Ordinary load analysis techniques stress on statistical processing of hourly load data along predefined time axes, producing numerical results of a standard granularity, such as daily or weekly mean loads. In order to overcome these limitations, a new approach or load analysis was developed, based on applying a two-dimensional formulation of the hourly load data. The tables holding energy consumption values, where columns represent the days of the selected period and lines represent the 24 hours of the day, are then illustrated through the use of colour patterns. In such a way, chronological typical units of variable structure and granularity can be identified and provide the basis for an extensive cross-examination, resulting in optimized decision making and energy policy definition. In order to demonstrate the advantages of the approach, a dedicated DSS implementation and application in the Greek public power corporation was also performed.
Netbill is a business model, set of protocols, and software implementation for supporting commerce in information goods and other network delivered services. It has very low transaction costs for micropayments (around...
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This paper presents an approach and computer program for material selection which integrates the environmental life cycle impacts of materials into traditional engineering material selection process. This computer pro...
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This paper presents an approach and computer program for material selection which integrates the environmental life cycle impacts of materials into traditional engineering material selection process. This computer prototype can be used as a decision support tool for material selection with comprehensive consideration of material properties, manufacturing processes, costs, and environmental impacts of a material's life cycle. This integrated tool makes life cycle analysis more practical and easier for engineers and can help them select materials with considerations of environmental life cycle impacts in the design stages.
NetBill is a business model, set of protocols, and software implementation for supporting commerce in information goods and other network delivered services. It has very low transaction costs for micropayments (around...
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NetBill is a business model, set of protocols, and software implementation for supporting commerce in information goods and other network delivered services. It has very low transaction costs for micropayments (around 1 cent for a 10cent item), protects the privacy of the transaction, and is highly scalable. Of special interest is our new certified delivery mechanism which delivers information goods if and only if the customer has payed for them. This paper discusses the design of the NetBill protocol and our World Wide Web (WWW) prototype implementation.
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