A testbed-based approach to the evaluation of fault-tolerant distributed computing schemes is discussed. The approach is based on experimental incorporation of system structuring and design techniques into real-time d...
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A testbed-based approach to the evaluation of fault-tolerant distributed computing schemes is discussed. The approach is based on experimental incorporation of system structuring and design techniques into real-time distributed computing testbeds centered around tightly coupled microcomputer networks. The effectiveness of this approach has been confirmed through some experiments conducted in the author's laboratory. Primary advantages of the testbed-based approach include the relatively high accuracy of the data obtained on timing and logical complexity as well as the relatively high degree of assurance that can be obtained on the practical effectiveness of the scheme evaluated. This paper discusses various design issues encountered in the course of establishing the basic microcomputer network testbed facilities and augmenting them to support some experiments conducted. The shortcomings of the testbeds that have been recognized are also discussed together with the desired extensions of the testbeds. Some of the desired extensions are beyond the state of the art in microcomputer network implementation. [ABSTRACT FROM AUTHOR]
作者：
PAKZAD, SComputer Engineering Program
Department of Electrical Engineering The Pennsylvania State University University Park Pennsylvania 16802 USA
The issue of the fault tolerance of interconnection networks has received considerable attention since the last decade. The theoretical framework developed by J. P. Shen and J. P. Hays ( IEEE Trans. Comput. C-33 , 3 (...
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The issue of the fault tolerance of interconnection networks has received considerable attention since the last decade. The theoretical framework developed by J. P. Shen and J. P. Hays ( IEEE Trans. Comput. C-33 , 3 (Mar. 1984), 241–248) and extended by S. Pakzad and S. Lakshmivarahan ( Internat. J. Comput. Syst. Sci. Engrg. 3 , 2 (April 1988), 91–99) can be used as a guideline to analyze the fault tolerance behavior of the interconnection networks in a multicomputer environment. This paper analyzes the fault tolerance characteristics of a range of rearrangeable β-networks based on the concepts and the framework developed by S. Pakzad and S. Lakshmivarahan (cited earlier). These rearrangeable β-networks include the Benes network, the Waksman network, the Joel network, and the serial network. In addition, this paper presents a comparative analysis of the aforementioned networks according to their hardware cost, performance, and degree of fault tolerance.
A new single-key-lock (SKL) mechanism used for implementing the access matrix of the computer protection system is proposed. The key selection is very flexible. The lock values are generated recursively based on the N...
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A new single-key-lock (SKL) mechanism used for implementing the access matrix of the computer protection system is proposed. The key selection is very flexible. The lock values are generated recursively based on the Newton's interpolating polynomial. The insertion of a new user/file into the system can be successfully implemented without recomputing all locks/keys. [ABSTRACT FROM AUTHOR]
We report the observation of electrically induced changes in transmissivity in Fabry-Perot devices consisting of spin-cast azo-dye/polymer films deposited between gold mirrors. In poled samples the observed modulation...
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We report the observation of electrically induced changes in transmissivity in Fabry-Perot devices consisting of spin-cast azo-dye/polymer films deposited between gold mirrors. In poled samples the observed modulation shows a linear dependence on the applied modulating voltage. The ratio of the transmissivity modulation observed using incident transverse magnetic polarization to that observed using transverse electric polarization is used to demonstrate that the electrooptic effect dominates the modulation. This is, to our knowledge, the first reported use of a polymeric thin film linear electrooptic material in a Fabry-Perot structure and demonstrates the use of etalons to enhance electrooptic effects in very thin films.
The Monte Carlo method is rapidly becoming the model of choice for simulating light transport in tissue. This paper provides all the details necessary for implementation of a Monte Carlo program. Variance reduction sc...
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This paper proposes a new ID-based cryptographic scheme for implementing public-key cryptosystem and signature. Instead of generating and publishing a public key for each user, the ID-based scheme permits each user to...
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Several different approaches are discussed for implementing conversations in loosely coupled distributed computer systems (DCSs). Important implementation factors considered include the control of exits of processes o...
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Several different approaches are discussed for implementing conversations in loosely coupled distributed computer systems (DCSs). Important implementation factors considered include the control of exits of processes on completion of their conversation tasks and the approach to execution of the conversation acceptance test. Two different exit control strategies, one in a synchronous manner and the other in an asynchronous manner, and three different approaches to execution of the conversation acceptance test, centralized, decentralized, and semi-centralized, are examined and compared in terms of system performance and implementation cost. The effectiveness of these execution approaches also depends on the way conversations are structured initially by program designers. Therefore, the two major types of conversation structures, name-linked recovery block and abstract data type conversations are examined to analyze which execution approaches are the most efficient for each conversation structure. These results provide guidelines for implementing conversations in loosely coupled DCSs.< >
A novel ID-based cryptographic scheme for implementing a public-key cryptosystem and signature is proposed. Instead of generating and publishing a public key for each user, the ID-based scheme permits each user to cho...
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A novel ID-based cryptographic scheme for implementing a public-key cryptosystem and signature is proposed. Instead of generating and publishing a public key for each user, the ID-based scheme permits each user to choose his/her name or network address as his/her public key. This eliminates the needs of a large public field and the exchange of private or public keys. The major advantage of the ID-based cryptosystem based on this scheme over other published ID-based cryptosystems is that the number of users can be extended to t*L users without degrading the system's security even when users conspire, where L is the number of the system's secrets, and t is the number of factors in p-1, where p is a large prime number.< >
A password authentication mechanism based on the public-key distribution cryptosystem is proposed. The scheme uses an authentication table to replace the traditional password file. With this scheme, even if the authen...
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A password authentication mechanism based on the public-key distribution cryptosystem is proposed. The scheme uses an authentication table to replace the traditional password file. With this scheme, even if the authentication table is comprised, the system security is preserved. The user's password is effectively bound to the user's identification in a timely, efficient, and simple manner.< >
Over the last several years the power of personal computers (PC) in enhancing teaching effectiveness in both classroom and laboratory has become universally recognized. The objective of this paper is to describe how P...
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