A flat strip antenna is embedded in a magnetoionic medium with its longitudinal axis perpendicular to the static magnetic field. The antenna characteristics differ for antennas oriented with their surfaces parallel an...
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A flat strip antenna is embedded in a magnetoionic medium with its longitudinal axis perpendicular to the static magnetic field. The antenna characteristics differ for antennas oriented with their surfaces parallel and perpendicular to the static magnetic field. In the former case there are no resistance peaks for frequencies near the plasma frequency and the reactance of a short antenna is capacitive for low frequencies. For frequencies near the gyrofrequency the antennas are electrically longer for the parallel orientation of their surfaces. The accuracy of the solutions is illustrated by computing the tangential electric surface fields that are excited by the approximate current distributions used in the impedance computations.
The variability and uncertainty inherent to wind generation, which is rapidly increasing, could significantly impact operations efficiency in the future, particularly frequency regulation reserves. This paper addresse...
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The variability and uncertainty inherent to wind generation, which is rapidly increasing, could significantly impact operations efficiency in the future, particularly frequency regulation reserves. This paper addresses these issues from both analytical and curative standpoints through operational impact studies which combine a transmission grid representation with a distributed agent-based control architecture that mimics industry organization charts and follows NERC reliability management rules. As simulating a control area over many years of recorded historical operating conditions is a massive computation problem, the new scheme uses distributed computing with 228 computing nodes to maintain a reasonable simulation time. The simulator-derived automatic generation control and load following generated with a data set characterizing 3000 MW of wind generation integrated in the Quebec interconnection were compared with statistical analysis-based results. The results of the simulation of a full year of minute-by-minute operations suggest that wind integration will increase the number of generating unit start-ups and shut-downs by approximately 5%. The simulator was also able to estimate import/export opportunity losses, as well as several impacts related to voltages and reactive power attributable to increased wind penetration.
The output distribution for the separable two-dimensional median filter and the square window two-dimensional median filter are derived for several cases, including first-order and multivariate output distributions wi...
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The output distribution for the separable two-dimensional median filter and the square window two-dimensional median filter are derived for several cases, including first-order and multivariate output distributions with white noise, signals plus white noise, and general multivariate input images. These are then used to compute some specific statistics in several illustrative examples.
Synchrotron X-ray microdiffraction (mu XRD) services are conducted for industrial minerals to identify their crystal impurities in terms of crystallinity and potential impurities. mu XRD services generate huge loads o...
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Synchrotron X-ray microdiffraction (mu XRD) services are conducted for industrial minerals to identify their crystal impurities in terms of crystallinity and potential impurities. mu XRD services generate huge loads of images that have to be screened before further processing and storage. However, there are insufficient effective labeled samples to train a screening model since service consumers are unwilling to share their original experimental images. In this article, we propose a physics law-informed federated learning (FL) based mu XRD image screening method to improve the screening while protecting data privacy. In our method, we handle the unbalanced data distribution challenge incurred by service consumers with different categories and amounts of samples with novel client sampling algorithms. We also propose hybrid training schemes to handle asynchronous data communications between FL clients and servers. The experiments show that our method can ensure effective screening for industrial users conducting industrial material testing while keeping commercially confidential information.
In the deregulated environment, information is the key to secure operation, profitability, customer retention, market advantage, and growth for the power industry. The rapid development of the Internet and distributed...
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In the deregulated environment, information is the key to secure operation, profitability, customer retention, market advantage, and growth for the power industry. The rapid development of the Internet and distributed computing have opened the door for feasible and cost-effective solutions. This article describes and demonstrates a unique Internet-based application in a substation automation system that is implemented based on the existing system control and data acquisition (SCADA) system and very large-scale integration (VLSI) information technologies (IT). The user can view the real-time data superimposed on one-line diagrams generated automatically using VLSI placement and routing techniques. In addition, the user can also control the operation of the substation at the server site. The choice of Java technologies, such as Java Native Interface (JNI), Java Remote Method Invocation (RMI), and Enterprise Java Bean (EJB), offers unique and powerful features, such as zero client installation, on-demand access, platform independence, and transaction management for the design of the online SCADA display system.
On-line monitoring can complement formal techniques to increase application dependability. This tutorial outlines the concepts and identifies the activities that comprise event-based monitoring, describing several rep...
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On-line monitoring can complement formal techniques to increase application dependability. This tutorial outlines the concepts and identifies the activities that comprise event-based monitoring, describing several representative monitoring systems.
This paper describes a security model developed from empirical data collected from a realistic intrusion experiment in which a number of undergraduate students were invited to attack a distributed computer system. Rel...
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This paper describes a security model developed from empirical data collected from a realistic intrusion experiment in which a number of undergraduate students were invited to attack a distributed computer system. Relevant data, with respect to their intrusion activities, were recorded continuously. We have worked out a hypothesis on typical attacker behavior based on experiences from this and other similar experiments. The hypothesis suggests that the attacking process can be split into three phases: the learning phase, the standard attack phase and the innovative attack phase. The probability for successful attacks during the learning phase is expected to be small and, if a breach occurs, it is rather a result of pure luck than deliberate action. During the standard attack phase, this probability is considerably higher, whereas it decreases again in the innovative attack phase. The collected data indicates that the breaches during the standard attack phase are statistically equivalent. Furthermore, the times between breaches seem to be exponentially distributed, which means that traditional methods for reliability modelling of component failures may be applicable.
This paper deals with the problem of store-and-forward deadlock prevention in store-and-forward networks. The presented solution uses time stamping of all messages in the network, and a nonpreemptable message exchange...
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This paper deals with the problem of store-and-forward deadlock prevention in store-and-forward networks. The presented solution uses time stamping of all messages in the network, and a nonpreemptable message exchange mechanism. By combining these ideas, a new distributed flow control procedure is derived which guarantees that all messages are delivered to their own destinations, thus avoiding both deadlock and livelock without any message loss. It is shown that some properties of this procedure depend on the policy of the allocation of exchange buffers to nodes. On the one hand, an optimal allocation strategy is presented which results in a maximally optimal deadlock prevention procedure. The procedure is network sizeand topology-independent and allows unrestricted packet routing. On the other hand, the allocation of one exchange buffer per node is discussed, which, even if not optimal, makes the derived deadlock prevention procedure completely independent of network reconfigurations. The last feature is extremely important from the practical point of view and, therefore, such a solution is strongly recommended. When compared to store-and-forward deadlock prevention procedures described so far, which lack some or all of these desirable properties, the procedure presented here behaves favorably. However, it imposes other drawbacks, i.e., the possibility of extra hops as a result of exchange operations. It is argued that this drawback appears rarely in practice, and some strategies which aim at a reduction of it are proposed.
AbstractSINA is an object‐oriented language for distributed and concurrent programming. The primary focus of this paper is on the object‐oriented concurrent programming mechanisms of SINA and their implementation. T...
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AbstractSINA is an object‐oriented language for distributed and concurrent programming. The primary focus of this paper is on the object‐oriented concurrent programming mechanisms of SINA and their implementation. This paper presents the SINA constructs for concurrent programming and inter‐object communication, some illustrative examples and a message‐based implementation model for SINA that we have used in our current impleme
We present a unified model to compute various performance measures when Poissonian and non-Poissonian (renewal) multi-slot traffic streams are offered to a digital link in a (double) loss system. We represent the non-...
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We present a unified model to compute various performance measures when Poissonian and non-Poissonian (renewal) multi-slot traffic streams are offered to a digital link in a (double) loss system. We represent the non-Poissonian arrival process by a matrix-exponential distribution, requiring only that the inter-arrival distribution has a rational Laplace transform. Several distributions are considered as the non-Poissonian traffic. The resulting model uses matrix algebraic techniques only, thus not requiring any complex and/or tedious transform techniques. We also incorporate various control policies in our modeling framework using acceptance functions. Through our computational studies, we conclude that the second and the third moments of the non-Poissonian traffic have significant impact on various performance measures.
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