networks of workstations and high-performance microcomputers have been rarely used for running high-performance applications like multimedia, simulations, scientific and engineering applications, because, although the...
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networks of workstations and high-performance microcomputers have been rarely used for running high-performance applications like multimedia, simulations, scientific and engineering applications, because, although they have significant aggregate computing power, they lack the support for efficient message-passing and shared-memory communication. In this paper we present Telegraphos, a distributed system that provides efficient shared-memory support on top of a workstation cluster. We focus on the network interface of Telegraphos that provides a variety of shared-memory operations like remote reads, remote writes, remote atomic operations, all launched from user level without any intervention of the operating system. Telegraphos I, the first Telegraphos prototype has been implemented. Emphasis was put on rapid prototyping, so the technology used was conservative: FPGA's, SRAM's, and TTL buffers. Telegraphos II, is the single-chip version of the Telegraphos architecture;its switch was implemented and its network interface is being debugged.
Global telecommunication systems are built with extensive redundancy and complex management systems to ensure robustness. Fault identification and managemeit of this complexity is an opB research issue with which data...
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This paper investigates the exponential stability of stochastic neural networks with unbounded discrete delays and infinitely distributed delays. By using Lyapunov functions, the semi-martingale convergence theorem an...
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ISBN:
(纸本)9783642211041
This paper investigates the exponential stability of stochastic neural networks with unbounded discrete delays and infinitely distributed delays. By using Lyapunov functions, the semi-martingale convergence theorem and some inequality techniques, the exponential stability in mean square and almost sure exponential stability are obtained. To overcome the difficulties from unbounded delays, some new techniques are introduced. Some earlier results are improved and generalized. An example is given to illustrate the results.
Time predictability is a central requirement for real-time systems. The correct behavior of such a system can only be achieved if the results of programs are ready in time to affect the environment. Execution times of...
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ISBN:
(纸本)9798350339024
Time predictability is a central requirement for real-time systems. The correct behavior of such a system can only be achieved if the results of programs are ready in time to affect the environment. Execution times of modern systems can vary for many reasons, meaning complex analyses must be performed to ensure that the execution time is bounded and that a task always finishes before its deadline. Care must also be taken to ensure that nefarious actors do not exploit the varying execution time to compromise the system's integrity. Avoiding variable execution times can greatly simplify systems, is inherently more secure, and eliminates the need for complex analyses. In this paper, we first argue for the value of having programs with constant execution times. We then show how the memory system around a processing core can affect execution times even on systems without intermediate storage like caches or scratch-pads. We present automatic compiler techniques for generating constant execution time programs and evaluate their implementation on the Patmos architecture. We show that combining our two compensation techniques is generally superior to either on their own. We compare the performance of our implementation to the estimates produced by the Platin worst-case execution time analyzer. While our implementation significantly impacts performance, it is generally manageable and has the potential for comparable execution times.
Effective data object replication protocols in today's competitive enterprise environment is an important issue. Fast and effective access to distributed object store is very important. Replication is considered a...
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ISBN:
(纸本)9789604740994
Effective data object replication protocols in today's competitive enterprise environment is an important issue. Fast and effective access to distributed object store is very important. Replication is considered a widely accepted phenomenon in distributed object systems, where object is replicated at more than one site to improve availability, reliability and the performance of data access. Many distributed object systems based on fully replication is suffering from the problem of one manager who is responsible for the store consistency and transaction serialization. These systems are suffering from bottleneck problem where there is no load balance between the nodes in the system. In this paper, a new approach for solving bottleneck problem and reducing the overhead of one manager node by extending to several managers nodes based on the Last Recently Used Updator (LRUU) algorithm is presented. This new protocol gives better load balancing between all nodes which improves the performance of transaction execution while assuring global system consistency. Here, the work presented in [6] is developed. To detect the required information, the entire data are collected together in a long vector and then tested as a one input pattern. Proposed fast time delay neural networks (FTDNNs) use cross correlation in the frequency domain between the tested data and the input weights of neural networks. It is proved mathematically and practically that the number of computation steps required for the presented time delay neural networks is less than that needed by conventional time delay neural networks (CTDNNs). Simulation results using MATLAB confirm the theoretical computations.
The proceedings contain 44 papers. The topics discussed include: a topological characterization of weakness;efficient dependency tracking for relevant events in shared-memory systems;building scalable and robust peer-...
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The proceedings contain 44 papers. The topics discussed include: a topological characterization of weakness;efficient dependency tracking for relevant events in shared-memory systems;building scalable and robust peer-to-peer overlay networks for broadcasting using network coding;skip webs: efficient distributed data structures for multi-dimensional data sets;brief announcement: an incentive-compatible capacity assignment algorithm for bulk data distribution using P2P;brief announcement: broadcast in radio networks in the presence of Byzantine adversaries;feedback control for router congestion resolution;toward a theory of transactional contention managers;and adaptive routing with stale information.
objective of paper is to provide qualitative insight into global effects of distributed mechanisms, such as carrier sense multiple access (CSMA) and rate control, on performance and stability of multi-hop wireless net...
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In a Radio Frequency (RF) Energy Harvesting Network (RF-EHN) the nodes have the capability of converting received electromagnetic RF signals in energy. Traditionally, the RF signals are provided by high power transmit...
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ISBN:
(纸本)9781509020614
In a Radio Frequency (RF) Energy Harvesting Network (RF-EHN) the nodes have the capability of converting received electromagnetic RF signals in energy. Traditionally, the RF signals are provided by high power transmitters operating in the neighborhood of the harvesters. Admitting that the transmitters are spatially distributed according to a spatial Poisson process, we start by characterizing the distribution of the RF power received by an energy harvester node. Considering path loss and fading effects, we provide a theoretical approximation for the distribution of the received RF power. Using the distribution of the received RF power, we derive the probability of a node having enough energy to transmit a packet after a given amount of battery charging time. The numerical results obtained with the proposed analysis are close to the ones obtained through simulation, which confirms the accuracy of the proposed analysis.
Rapid updating of any application is necessary to permit iterative design and development. This task is significantly complicated when an application is distributed. Rather than using the traditional methods of softwa...
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ISBN:
(纸本)0818608420
Rapid updating of any application is necessary to permit iterative design and development. This task is significantly complicated when an application is distributed. Rather than using the traditional methods of software dissemination and installation, the GRANDiose distributed Application System permits authorized programmers around a wide area network to install and operate systems at remote sites. This is done using the facilities of GRAND, a test bed for distributed applications. The system is in experimental use on various wide area networks and LANs.
Despite the fact that a number of research efforts in the area of Industrial Wireless Sensor networks (IWSNs) exist, there is a lack of really practical IWSN implementations, deployments, and in-field applications. Th...
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Despite the fact that a number of research efforts in the area of Industrial Wireless Sensor networks (IWSNs) exist, there is a lack of really practical IWSN implementations, deployments, and in-field applications. This paper presents the design and implementation of an IWSN for welder machine systems, called WirelessCAN which is based on WirelessHART to replace wired CAN fieldbus. Although the implementation and challenges are application-specific, we believe that the problems we encountered will be faced by many IWSN designers. In this paper, selected challenges exposed in our implementation and the potential solutions are introduced, which have not been addressed previously. Specifically, communication resource constraint, real-time rescheduling, integrated knowledge for IWSN applications, centralized control architecture, reliable and immediate message delivery for human and equipment safety, and differential QoS requirements are discussed in detail and in depth. The goal of this paper is to make the design and implementation of IWSNs more efficient and applicable.
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