This paper presents an efficient method to evaluate the performance of an extended stochastic Petri net by simple algebraic operations. The reachability graph is derived from an extended stochastic Petri net, and then...
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This paper presents an efficient method to evaluate the performance of an extended stochastic Petri net by simple algebraic operations. The reachability graph is derived from an extended stochastic Petri net, and then converted to a timed stochastic state machine, using a semi-Markov process. The n-th moments of the performance index are derived by algebraic manipulations with each of the n-th moments of transition time and transition probability. For the derivation, three reduction rules are introduced on the transition trajectories in a well-formed regular expression. Efficient comp.tation algorithms are provided to automate the suggested method. The presented method provides a proficient means to derive both the numerical and the symbolic solutions for the performance of an extended stochastic Petri net by simple algebraic manipulations.
Bluetooth ad hoc personal area network is one independent wireless network comp.sed of Bluetooth enabled mobile devices, which can freely communicate and collaborate with each other in some area without extra infrastr...
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Bluetooth ad hoc personal area network is one independent wireless network comp.sed of Bluetooth enabled mobile devices, which can freely communicate and collaborate with each other in some area without extra infrastructure. Some nodes in Bluetooth ad hoc personal area networks participate in multiple piconets in time division duplex and forward network traffic. It needs one inter-piconet or scatternet scheduling algorithm since at a time the node presents in only one of the piconets it participates. Sniff mode provides a flexible method to support inter-piconet scheduling scheme without protocol modification. A self-adaptive scatternet scheduling algorithm is presented based on sniff mode to efficiently deal with the challenging issue. According to the supervised dynamic traffic of the physical links, the algorithm adjusts in real time the allocation ratio of the node's time slots to its connected links. With the comp.rison and analysis of the results of the simulation in various flow models, it validates that the algorithm can enhance the throughput of the system, lower the delay of the system and then improve the performance of the network.
Based on Lotus Domino groupware system, the office automation (OA) system can support many kinds of users, including Notes users and Web users. But it is impossible to use the same method to identify the Web users vis...
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Based on Lotus Domino groupware system, the office automation (OA) system can support many kinds of users, including Notes users and Web users. But it is impossible to use the same method to identify the Web users visiting the OA system as it does when it identifies the Notes users, not to speak of controlling the Web user's access to the OA databases. Therefore this paper proposes a project based on session to verify the Web user's ID and password using resident Java Servlets on Domino server. Based on the structure and security mechanism of Domino OAS, the paper discusses the authentication project, and comp.res the project with other projects. It indicates that the project can not only implement the authentication of the Web user effectively, but also make the control of the user's access to the OA databases neatly.
Due to the scalability problem of Integrated Services (IntServ) network, Differentiated Services (DiffServ) architecture was proposed to provide Quality of Services (QoS) support for aggregate traffic rather than indi...
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Due to the scalability problem of Integrated Services (IntServ) network, Differentiated Services (DiffServ) architecture was proposed to provide Quality of Services (QoS) support for aggregate traffic rather than individual flows. It requires no per-flow state management and signaling process at each router. However, DiffServ can not provide end-to-end QoS guarantees for aggregated flows because of lacking effective Connection Admission Control (CAC) mechanism. This paper presents a distributed and scalable admission control scheme to provide end-to-end statistical QoS guarantee for DiffServ network. The scheme consists of three main elements;(1) a new sender-initiated admission control protocol to transfer messages between end hosts and edge routers, or edge router and bandwidth broker, (2) available bandwidth measurement and estimation, and (3) admission control algorithm. Authors present an example of applying the proposed scheme to object-based video transmission. The performance of the scheme is evaluated with a variety of QoS metrics and network topologies. The simulation results demonstrate that the proposed scheme can accurately control the admissible region and effectively improve the utilization of network resource.
A new hybrid algorithm - the neural evolutionary algorithm for solving the maximal independent set problems is proposed. The algorithm is based on space division and exclusion strategies. It effectively integrates the...
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A new hybrid algorithm - the neural evolutionary algorithm for solving the maximal independent set problems is proposed. The algorithm is based on space division and exclusion strategies. It effectively integrates the special advantages of fast convergence of neural networks and robust global search capability of genetic algorithms. As comp.red with the standard genetic algorithm and the Hopfield neural network, the proposed algorithm demonstrates quite high global optimization capability and comp.ting efficiency.
The reliability of Cu dual-damascene interconnect trees with 3-terminal (dotted-I), 4-terminal ('T') and 5-terminal ('+') configurations has been investigated. The lifetime of multi-terminal interconne...
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The reliability of Cu dual-damascene interconnect trees with 3-terminal (dotted-I), 4-terminal ('T') and 5-terminal ('+') configurations has been investigated. The lifetime of multi-terminal interconnect trees with the same current density through the common middle via was determined to be independent of the number of segments connected at the common junction. Furthermore, our experimental results on dotted-I test structures showed an increase in the reliability of the interconnect tree when the distribution of a same current was not equal in the two connected segments, especially for the cases where one of the segments was acting as a passive reservoir or active source of Cu atoms for the adjoining segment. Due to the low barrier for void nucleation at the Cu/Si3N4 interface, the presence of any small atomic source in neighboring segments with enhance the reliability of a connected segment in which Cu atoms are being drained away. As a consequence, failure can occur in a tree segment which is stressed at significantly lower current densities than more highly stressed adjoining segments.
In a Code Division Multiple Access (CDMA) system, the optimum weight vector of an adaptive antenna array is the principal eigenvector (eigenvector corresponding to the maximum eigenvalue) of the covariance matrix of t...
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In a Code Division Multiple Access (CDMA) system, the optimum weight vector of an adaptive antenna array is the principal eigenvector (eigenvector corresponding to the maximum eigenvalue) of the covariance matrix of the received signal at the output of the despreader. Consequently the weight vector can be comp.ted by solving a Simple Eigenvalue problem (SE). In this paper we develop a new adaptive algorithm based on the Lagrange Multiplier technique to solve the SE. The comp.tational comp.exity of the proposed algorithm is linear with the number of antenna elements. We investigate different aspects like the convergence and tracking property of the proposed algorithm. We employ a Beamformer-Rake receiver at the uplink of a Wideband CDMA (WCDMA) system to test the performance of the adaptive algorithm. We comp.re the proposed algorithm with another Lagrange Multiplier based algorithm [6] in terms of comp.tational comp.exity, rate of convergence and Bit Error Rate (BER) performance of the Beamformer-Rake receiver in multipath environment.
The minimal surfaces are extensively employed in many areas such as architecture, aviation, ship manufacture, and so on. However, the comp.exity of the minimal surface equation prevents people from modeling the minima...
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The minimal surfaces are extensively employed in many areas such as architecture, aviation, ship manufacture, and so on. However, the comp.exity of the minimal surface equation prevents people from modeling the minimal surface in CAD/CAGD. Based on the nonlinear programming and the FEM (finite element method), the approximation to the solution of the minimal surface equation bounded by Bezier or B-spline curves is investigated. A global method, which is called numerical extension method, is appealed to in the whole iterative process and linearize the nonlinear finite element system by using a simple iteration. Some numerical results are given.
For the load balancing problem of distributed system, it is very important that how to assign tasks to the leisure workstations and share processing resources by parallel network comp.ting so as to accomp.ish the task...
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For the load balancing problem of distributed system, it is very important that how to assign tasks to the leisure workstations and share processing resources by parallel network comp.ting so as to accomp.ish the task as soon as possible. Recently, the load balancing problem of multiprocessor is becoming one of new research directions. In this paper, a mathematical model for load balancing of multiprocessor is proposed, which solves the problem of load balancing by factors decomp.sing of graphs. Let G is an undirected graph with weight, and G′ is a directed bipartite graph made from G. It is proved that the problem about fractional 1-factor of G is equal to the problem about 1-factor of G′. By using this result, an O(n2) time algorithm of load balancing of multiprocessor is given, where n is the sum of workstations and tasks.
This paper presents a design of a dual-rail multiple-valued current-mode (MVCM) circuit using two supply voltages and biasing current sources. The switching delays of both a threshold detector (TD) and a current mirro...
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This paper presents a design of a dual-rail multiple-valued current-mode (MVCM) circuit using two supply voltages and biasing current sources. The switching delays of both a threshold detector (TD) and a current mirror, which are the basic comp.nents of the dual-rail MVCM circuit, depend on the gate-to-source voltage swing. The use of two supply voltages and biasing current sources makes the voltage swing small, which results in high-speed switching as well as low power dissipation. As a typical example of the proposed dual-rail MVCM circuit, a radix-2 signed-digit full adder (SDFA) is designed and fabricated using a 0.35-μm CMOS technology. Its performance is superior to the SDFA with a single supply voltage and no biasing current sources.
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