This study presents new risk analysis tools and demonstrates the feasibility and applicability of these tools in the design verification of railway interlocking control systems and deadlock prevention in automated man...
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This study presents new risk analysis tools and demonstrates the feasibility and applicability of these tools in the design verification of railway interlocking control systems and deadlock prevention in automated manufacturing systems. Our verification methodology consists of the following stages. First, we analyze the rules executed by the controller and extract a state machine model of the controller. Second, we compose safety, reliability, and operability system specifications using a propositional temporal logic. Finally, we use the model checker to check the state machine model of the system against its requirements. The verification approach allows an exhaustive search of all possible behaviors and scenarios. We verified two real railway interlocking control applications with 125 and 452 constraints respectively. Checking two opposing signal protection specifications involving 3 signals ranged between 74 and 1223 seconds depending on the size and the complexity of the interlocking. Traditional verification methods typically require several person weeks.
Modal transformation technique is a common tool for transmission line transient computations. A simplified modal decomposition of overhead transmission lines, suitable for time‐domain switching (up to 105 Hz) transie...
In designing a compensator for a robust force controlled grinding system several constraints must be considered. It is critical that the grinding force is decoupled from the feed velocity of the system. Therefore, two...
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In designing a compensator for a robust force controlled grinding system several constraints must be considered. It is critical that the grinding force is decoupled from the feed velocity of the system. Therefore, two separate control loops are designed, a feed velocity loop and a force loop. Besides decoupling the force and velocity, a variety of other system performance specifications must be achieved. To aid in the design of the control loops, several parametric plots are used to visualize the effects of various control parameters on the closed-loop system dynamics as well as the coupling of the two loops.< >
Historically, there has been tension between performance and privacy of information systems because of the crucial role of collection of usage data. In this paper, we examine how a number of different architectures ap...
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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 ...
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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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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.
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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