Physical Sciences and Mathematics Commons^™

Parity Retransmission Hybrid Arq Using Rate 1/2 Convolutional Codes On A Nonstationary Channel, L. R. Lugand, D. J. Costello, Jr., Robert H. Deng

Research Collection School Of Computing and Information Systems

A parity retransmission hybrid automatic repeat request (ARQ) scheme is proposed which uses rate 1/2 convolutional codes and Viterbi decoding. A protocol is described which is capable of achieving higher throughputs than previously proposed parity retransmission schemes. The performance analysis is based on a two-state Markov model of a nonstationary channel. This model constitutes a first approximation to a nonstationary channel. The two-state channel model is used to analyze the throughput and undetected error probability of the protocol presented when the receiver has both an infinite and a finite buffer size. It is shown that the throughput improves as the …

High Rate Concatenated Coding Systems Using Bandwidth Efficient Trellis Inner Codes, Robert H. Deng, D. J. Costello, Jr.

Research Collection School Of Computing and Information Systems

High-rate concatenated coding systems with bandwidth-efficient trellis inner codes and Reed-Solomon (RS) outer codes are investigated for application in high-speed satellite communication systems. Two concatenated coding schemes are proposed. In one the inner code is decoded with soft-decision Viterbi decoding, and the outer RS code performs error-correction-only decoding (decoding without side information). In the other the inner code is decoded with a modified Viterbi algorithm, which produces reliability information along with the decoded output. In this algorithm, path metrics are used to estimate the entire information sequence, whereas branch metrics are used to provide reliability information on the decoded sequence. …

Parameter Non-Stationarity In A Model To Estimate The Business Value Of Information Technology, Robert J. Kauffman

Research Collection School Of Computing and Information Systems

Developing robust and refined measures to quantify strategic impacts is a major challenge facing researchers who seek to improve methods for IT investment evaluation. This paper presents a means to test for parameter "non-stationarity" in a model which quantifies the strategic contribution of IT. An iterative "jackknife" procedure is used to diagnose if different local competitive and demographic conditions present in branch banking enhance or suppress leverage on deposit market share associated with membership in an ATM network. Preliminary results suggest this approach will be useful for managers who need to evaluate similar ITs which operate in different environments.

Dc-Free Coset Codes, Robert H. Deng, M. A. Herro

Research Collection School Of Computing and Information Systems

An upper bound on the bit-error probability (BEP) of a linear cyclic code over GF(2l) with hard-decision (HD) maximum-likelihood (ML) decoding on memoryless symmetric channels is derived. Performance results are presented for Reed-Solomon codes on GF(32), GF(64), and GF(128). Also, a union upper bound on the BEP of a linear cyclic code with either hard- or soft-decision ML decoding is developed, as well as the corresponding bounds for the extended code of a linear cyclic code. Using these bounds, which are tight at low bit error rate, the performance advantage of soft-decision (SD) ML and HD ML over bounded-distance (BD) …

Decoding Of Dbec-Tbed Reed-Solomon Codes, Robert H. Deng, Daniel J. Jr. Costello

Research Collection School Of Computing and Information Systems

A problem in designing semiconductor memories is to provide some measure of error control without requiring excessive coding overhead or decoding time. In LSI and VLSI technology, memories are often organized on a multiple bit (or byte) per chip basis. For example, some 256K bit DRAM's are organized in 32K ?? 8 bit-bytes. Byte-oriented codes such as Reed-Solomon (RS) codes can provide efficient low overhead error control for such memories. However, the standard iterative algorithm for decoding RS codes is too slow for these applications. In this correspondence we present a special decoding technique for double-byte-error-correcting (DBEC), triple-byte-error-detecting (TBED) RS …

Reliability And Throughput Analysis Of A Concatenated Coding System, Robert H. Deng, Daniel J. Costello

Research Collection School Of Computing and Information Systems

The performance of a concatenated coding scheme for error control in ARQ systems is analyzed for both random error and burst-error channels. In particular, the probability of undetected error and the system throughput are calculated. In this scheme, the inner code is used for both error correction and error detection, and the outer code is used for error detection only. Interleaving/deinterleaving of the outer code is assumed. A retransmission is requested if either the inner code or the outer code detects the Presence of errors. Various coding examples are considered. The results show that concatenated coding can provide extremely high …

Impact Of Automation On Process Control Decision-Making, Steven M. Miller, Susan R. Bereiter

Research Collection School Of Computing and Information Systems

This paper investigates changes in the process control of a vehicle assembly plant which had been modernized from a principally manual procedure to one that uses programmable automation extensively. Process control is defined as the information flow and decision-making required to perform basic process operations. We investigate the effects of implementing a computer-integrated production system on the amount and types of process control decision-making and on the distribution of process control decision-making between humans and machines. After automation, the emphasis on decisions regarding product quality specifications increased and the emphasis on decisions related to flexibility in handling a variety of …

Impacts Of Robotics And Flexible Manufacturing Technologies On Manufacturing Costs And Employment, Steven M. Miller

Research Collection School Of Computing and Information Systems

The issues analyzed in this paper are the extent to which unit costs and production labor requirements might be reduced in manufacturing industries if there is more widespread use of industrial robots and flexible systems. The analysis is reported in detail in Miller (1983). These issues are analyzed from two different perspectives. The technological focus of the first perspective is narrowly confined to the use of robotic manipulators. It is assumed that robotic manipulators will be “retrofitted” into existing production facilities without making major changes in the organization of production within the factory, other than modifying individual work stations so …

Robotic Realities: Near Term Prospects And Problems, Robert U. Ayres, Steven M. Miller

Research Collection School Of Computing and Information Systems

Industrial robots are automation, but with a difference. Other machine tools are extensions of human capabilities, while robots are seen mainly as substitutes for human workers. Robots will find most of their industrial applications during the next decade or two in the metal-working sectors, where they will begin to displace semiskilled machine operatives in medium to large batch production operations. They cannot substitute for skilled machinists or other workers doing nonroutine jobs, or specialized, dedicated hard automation used in mass production. The current generation of robots, lacking sensory data processing and interpretation capabilities, can potentially replace up to 1.3 million …

Robotics And The Conservation Of Human Resources, Robert U. Ayres, Steven M. Miller

Research Collection School Of Computing and Information Systems

Due to rapid expansion in the field of robotics, policy issues have arisen in regard to developing human skills to deal with the new technology and to deal with the obsolescent human skills which are the inevitable result of this growth pattern. Industrialists, educators, union leaders, and government officials must work cooperatively to insure that the coming changes are made with minimum disruption. Improved training methods and courses have to be developed for the skills needed to control, manage and supervise the new machines. Some of the ways in which this can be accomplished are through offering financial incentives for …

The Role Of Technological Change, Robert U. Ayres, Steven M. Miller

Research Collection School Of Computing and Information Systems

We develop an optimal growth model that includes several important new features. First, technological change is endogenously related to the growth of 'knowledge.' Investment may be directed either towards physical capital or knowledge (or both). Knowledge becomes an effective substitute for scarce resources by increasing the technical efficiency of resource utilization both for consumption and in capital. Nevertheless, a finite quantity resource must be embodied in capital and a finite flow is required for depreciation. Thus, there is an upper limit to technical efficiency and economic growth is thus ultimately limited by the availability of renewable resources. For a simple …

Correction To "Redundancy Optimization Of General Systems", H. Sivaramakrishnan, Arcot Desai Narasimhalu

Research Collection School Of Computing and Information Systems

Reader Aids-

Purpose: Report a correction

Special math needed: Probability

Results useful to: Reliability Theoreticians

Efficient Employment Of Cohorts Of Labor In The U.S. Economy: An Illustration Of A Method, A. E. Boardman, Steven M. Miller, A. P. Schinnar

Research Collection School Of Computing and Information Systems

This paper presents a model for the analysis of efficient labor force participation in the U.S. economy. Ridge regression estimates of the elasticities of cohorts of labor, classified by sex and occupation, are used in conjunction with wage data to illustrate the derivation of efficient allocation of labor cohorts in five economic sectors. These efficient constructs are compared with actual census data for 1960 and 1970. The results, while tentative, show a trend toward more efficient utilization of labor and greater participation by women in the work force.

A Rapid Algorithm For Reliability Optimization Of Parallel Redundant Systems, Arcot Desai Narasimhalu, H. Sivaramakrishnan

Research Collection School Of Computing and Information Systems

A rapid method is proposed for optimization of reliability of multiconstraint parallel redundant systems. The constraints need not be linear. This method provides good starting values, which are close to the boundary of the feasible region, for the number of redundant units in each subsystem. No proof has been presented to establish the optimality obtained by this method. Yet for examples tried out this method provides optimal or near optimal solutions.