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IEEE Annual Joint Conference: INFOCOM, IEEE computer and Communications Societies

作者： Chao-Ju Hou Bin Wang Ching-Chih Han Computer Engineering Division Department of Elect. and Comput. Eng. University of Wisconsin Madison WI USA Real-Time Computing Laboratory Department of Elect. Eng. and Comput. Science University of Michigan Ann Arbor MI USA

ISBN: (纸本)0818672935

Based on the POPSMAC protocol proposed in Chung-Sheng Li et al. (1993), we propose an improved medium access protocol for wavelength division multiple access (WDMA) photonic networks. Using the same set of photonic devices as in POPSMAC, the proposed protocol alleviates the drawbacks of the POPSMAC protocol, e.g., invalid data transmissions following receiver collisions and possible acknowledgement packet collisions with header/data packets, while retaining many advantages of POPSMAC. As a result, the network performance in terms of the throughput and the packet delay is improved. Analytical models based on the timing diagram analysis, the continuous-time Markov chain, and the randomization technique are developed to assess the performance of the proposed protocol. The performance is evaluated in terms of channel utilization, mean packet delay, and packet delay distribution with variations in the number of nodes, the offered traffic, the size of data packets, and the network propagation delay. Numerical results show that the proposed protocol achieves better channel utilization and incurs lower packet delays than POPSMAC.

关键词： Access protocols Propagation delay Data communication Optical receivers Throughput Analytical models Timing Performance analysis Telecommunication traffic Traffic control

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computing time-DELAY AND ITS EFFECTS ON REAL-time CONTROL-SYSTEMS

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IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY 1995年第2期3卷 218-224页

作者： SHIN, KG CUI, XZ Real-Time Computing Laboratory Division of Comuuter Science and Engineering. Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI USA

The reliability of a real-time digital control computer depends not only on the reliability of the hardware and software used, but also on the time delay in computing the control output, because of the negative effects of computing time delay on control system performance. For a given fixed sampling interval, the effects of computing time delay are classified into the delay and loss problems, The delay problem, occurs when the computing time delay is nonzero but smaller than the sampling interval, while the loss problem occurs when the computing time delay is greater than, or equal to, the sampling interval, i,e., loss of the control output, These two problems are analyzed as a means of evaluating real-time control systems, First, a generic analysis of the effects of computing time delay is presented along with necessary conditions for system stability, Then, we present both qualitative and quantitative analyses of the computing time delay effects on a robot control system, deriving upper bounds of the computing time delay with respect to system stability and system performance.

关键词： Delay effects Real time systems Control systems Sampling methods System performance Stability analysis Digital control Hardware Software performance Performance analysis

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PROBING AND FAULT INJECTION OF DEPENDABLE DISTRIBUTED PROTOCOLS

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computer JOURNAL 1995年第4期38卷 286-300页

作者： DAWSON, S JAHANIAN, F Real-Time Computing Laboratory Electrical Engineering and Computer Science Department University of Michigan Ann Arbor MI 48109-2122 United States

Ensuring that a distributed system with strict dependability constraints meets its prescribed specification is a growing challenge that confronts software developers and system engineers. This paper presents a technique for probing and fault injection of fault-tolerant distributed protocols. The proposed technique, called script-driven probing and fault injection, can be used for studying the behaviour of distributed systems and for detecting design and implementation errors of fault-tolerant protocols. The focus of this work is on fault injection techniques that can be used to demonstrate three aspects of a target protocol: detection of design or implementation errors;identification of violations of protocol specifications;and insight into design decisions made by the implementers. The emphasis of our approach is on experimental techniques intended to identify specific ''problems'' in a protocol or its implementation rather than the evaluation of system dependability through statistical metrics such as fault coverage. To demonstrate the capabilities of this technique, the paper describes a probing and fault injection toot, called the PFI tool (probe/fault injection tool), and a summary of several extensive experiments that studied the behaviour of two protocols: the Transmission Control Protocol (TCP) and a group membership protocol (GMP).

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OPEN FAULTS IN BICMOS GATES

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IEEE TRANSACTIONS ON computer-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS 1995年第5期14卷 567-575页

作者： MA, SC MCCLUSKEY, EJ Center for Reliable Computing Computer Systems Laboratory Department of Electrical Engineering and Computer Science University of Stanford Stanford CA USA

Opens in BICMOS structures are analyzed here. It is shown that some opens cannot be detected by stuck-fault or other functional tests, since some transistors in BiCMOS gates do not affect the logical function of the gate. A switch-level model for CMOS circuits is extended to include bipolar devices. With this switch-level model, opens that cannot be detected by stuck-faults or other functional tests are easily identified. It is also shown that, in BICMOS circuits, an open defect in one transistor can accelerate the wearout of another nondefective transistor.

关键词： BiCMOS integrated circuits Circuit faults Circuit testing Semiconductor device modeling Logic testing Delay MOSFETs Switching circuits Acceleration CMOS technology

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Deterministic fault injection of distributed systems

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International Workshop on Theory and Practice in Distributed Systems

作者： Dawson, S Jahanian, F Real-Time Computing Laboratory Electrical Engineering and Computer Science Department University of Michigan Ann Arbor 48109-2122 MI United States

ISBN: (纸本)3540600426

Ensuring that a system meets its prescribed specification is a growing challenge that confronts software developers and system engineers. Meeting this challenge is particularly important for distributed systems with strict dependability and timeliness constraints. This paper presents a technique, called script-driven probing and fault injection, for the evaluation and validation of dependable protocols. The proposed approach can be used to demonstrate three aspects of a target protocol: i) detection of design or implementation errors, ii) identification of violations of protocol specifications, and iii) insight into design decisions made by the implementers. To demonstrate the capabilities of this technique, the paper briefly describes a probing and fault injection tool called the PFI tool, and several experiments on two protocols: the Transmission Control Protocol (TCP) [4, 24] and the Group Membership Protocol (GMP) [19]. The tool can be used to delay, drop, reorder, duplicate, and modify messages. It can also introduce new messages into the system to probe participants. In the case of TCP, we used the PFI tool to duplicate the experiments reported in [7] on several TCP implementations without access to the vendors' TCP source code in a very short time. We also ran several new experiments that are difficult to perform using past approaches based on packet monitoring and filtering. In the case of GMP, we used the tool to test the fault-tolerance capabilities of an implementation under various failure models including daemon/link crash, send/receive omissions, and timing failures. Furthermore, by selective reordering of messages and spontaneous transmission of new messages, we were able to guide a distributed computation into hard to reach global states without instrumenting the protocol implementation.

关键词： Transmission control protocol

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PP-MESS-SIM: A simulator for evaluating multicomputer interconnection networks 28

PP-MESS-SIM: A simulator for evaluating multicomputer interc...

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28th Annual Simulation Symposium, ANSS 1995

作者： Rexford, Jennifer Dolter, James Feng, Wu-chang Shin, Kang G. Real-Time Computing Laboratory Department of Electrical Engineering and Computer Science University of Michigan Ann ArborMI48109-2122 United States

ISBN: (纸本)0818670916

This paper presents pp-mess-sim, an object-oriented discrete-event simulation environment for evaluating multicomputer networks. The simulator provides a toolboz of various network topologies, communication workloads, routing-switching algorithms, and router models. These router models can vary from high-level architectures to low-level specification of actual devices. By decoupling individual parts of the code, pp-mess-sim enables independent code development and creates a flexible and extensible environment for evaluating different aspects of network design. Sample simulation experiments capitalize on this flezibility to compare routing-switching schemes under various application workloads. © 1995 IEEE

关键词： Discrete event simulation

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QoS-Sensitive protocol processing in shared-memory multiprocessor multimedia servers 3

QoS-Sensitive protocol processing in shared-memory multiproc...

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3rd IEEE Workshop on the Architecture and Implementation of High Performance Communication Subsystems, HPCS 1995

作者： Mehra, A. Shin, Kang G. Real-Time Computing Laboratory Department of Electrical Engineering and Computer Science University of Michigan Ann ArborMI48109-2122 United States

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Non-preemptive scheduling of messages on controller area network for real-time control applications

Non-preemptive scheduling of messages on controller area net...

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1995 Real-time Technology and Applications Symposium, RTAS 1995

作者： Zuberi, Khawar M. Shin, Kang G. Real-Time Computing Laboratory Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI 48109-2122 United States

Scheduling messages on the controller area network (CAN) corresponds to assigning identifiers (IDs) to messages according to their priorities. If fixed priority scheduling such as deadline monotonic (DM) is used to calculate these priorities, then in general, it will result in low schedulability. Dynamic scheduling schemes such as earliest deadline (ED) can give greater schedulability, but they are not practical for CAN because if the ID is to reflect message deadlines then a long ID must be used. This increases the length of each message to the point that ED is no better than DM. Our solution to this problem is the mixed traffic scheduler (MTS), which is a cross between ED and DM, and provides high schedulability without needing long IDs. Through simulations, we compare the performance of MTS with that of DM and ED* (an imaginary scheduler which works like ED, except it needs only short IDs). We use a realistic workload in our simulations based on messages typically found in computer integrated manufacturing. Our simulations show that MTS performs much better than DM and at the same level as ED, except under high loads and tight deadlines, when ED* is superior. © 1995 IEEE.

关键词： Real time control

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Fabrication of InP/InGaAs quantum wires by free Cl2

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Journal of Vacuum science & Technology B: Microelectronics Processing and Phenomena 1995年第6期13卷 2752-2752页

作者： Panepucci, R. Youtsey, C. Turnbull, D.A. Gu, S.Q. Caneau, C. Bishop, S.G. Adesida, I. Center for Compound Semiconductor Microelectronics Coordinated Science Laboratory and Department of Electrical and Computer Engineering University of Illinois Urbana Illinois 61801 Bell Communications Research Red Bank New Jersey 07701

Free Cl2 etching of InP/In0.53Ga0.47As at high temperatures was investigated for the fabrication of nanostructures. The effects of Cl2 flow rate, mask material, and substrate temperature on the sample etch rate, surface morphology, and etch profile are described. The etch profile is found to be temperature dependent for stripes along the crystal directions studied, namely, 〈110〉, 〈11̄0〉, and 〈010〉. The profile was affected by the choice of mask material among Ti and SiO2. The etch characteristics are found to be suitable for controlled etch of quantum wires. The etch technique is compatible with in situ etch and regrowth when SiO2 is used as the etch mask, since InP does not grow on SiO2 surfaces and allows selective regrowth immediately after etching. Quantum well wires (QWWs) with widths as low as 30 nm were fabricated using electron beam lithography and free‐Cl2 etching. Low temperature photoluminescence (PL) was used to characterize the QWWs. The normalized PL efficiency of narrow free‐Cl2 etched QWWs was found to be higher than that of ion‐assisted dry‐etched wires and comparable to that of wet‐etched wires.

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Mapping concurrently-communicating modules onto mesh multicomputers equipped with virtual channels

Mapping concurrently-communicating modules onto mesh multico...

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International Conference on Distributed computing Systems

作者： Bing-Rung Tsai K.G. Shin Real-Time Computing Laboratory Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI USA

It is difficult to define and evaluate a meaningful performance metric when many packets are generated and exchanged concurrently in mesh-connected multicomputers equipped with wormhole switching and virtual channels. Thus, an approximate metric/cost function must be chosen so that when, task modules are mapped by optimizing this function, the actual performance of the mapping is also optimized. Several low-complexity cost functions are evaluated using the simulated annealing optimization process. The mappings found by optimizing these cost functions are then fed into a flit-level simulator to evaluate their actual performance. One particular cost function is found to be very effective.

关键词： Cost function Measurement Packet switching Simulated annealing

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