An Approach to the Analysis of Performance of Quasi-Optimum Digital Phase-Locked Loops

An approach to the analysis of performance of quasioptimum digital phase-locked loops (DPLL's) is presented. An expression for the characteristic function of the prior error in the state estimate is derived, and from this expression an infinite dimensional equation for the prior error variance is obtained. The prior errorvariance equation is a function of the communication system model and the DPLL gain and is independent of the method used to derive the DPLL gain. Two approximations are discussed for reducing the prior error-variance equation to finite dimension. The effectiveness of one approximation in analyzing DPLL performance is studied.     

The component acids of kamala oil (Mallotus Philippinensis,Muell. Arg.)

Summary Kamala oil has been found to contain about 60% of kamlolenic acid as the only major component with minor proportions of common linoleic, oleic, and saturated acids and probably some conjugated diethenoid acid. The saturated components consist mostly of myristic and palmitic acids. Consecutive extraction of kamala seeds with petroleum ether and ethyl ether yields two fractions of the oil, containing about 40% and 80% of kamlolenic acid, respectively. During storage a portion of the unsaturated glycerides seems to undergo polymerization within the seed itself and appears as an insoluble gelatinous mass during saponification of the oil.     

Microcomputers in Industrial Control Applications

In their thirteen years of existence, microprocessor chips have evolved through four generations. Contemporary 16-bit and 32-bit microprocessors offer sophisticated architectures and powerful instruction sets. However, in many industrial applications, data rates are very high and the control structure has a decentralized configuration. In either case, multiple processors must be used. The major constraint in multiprocessor systems is usually the speed of the interconnection mechanism used for communication between the computing elements. This paper covers several of these issues. First, it compares and contrasts the performance of advanced microprocessors. Second, it discusses a split transaction protocol that mitigates the problem of overloading of the interconnection bus. Third, it describes an interactive tool to model multimicroprocessor systems. Overall this paper enumerates the steps involved in the design of efficient multimicroprocessor-based systems.     

Paralytic poliomyelitis (1989-1994): report from a sentinel center

OBJECTIVE: To study the trends of paralytic poliomyelitis in pre Pulse Polio Immunization period. SETTING: Hospital based sentinel surveillance. METHODS: Analysis of 6704 line-listed poliomyelitis cases from January 1989 to December 1994 attending the Department of Physical Medicine and Rehabilitation. RESULTS: 85% of all cases reported in Delhi were from this center. A decline in alternate year peaks was observed from 1621 cases in 1990 to 1062 cases in 1994. There was an increase in proportion of cases with poliomyelitis in fully vaccinated children from 14% to 22.9%. Polio type I virus was the commonest isolated virus in all the years except 1993, when type II was isolated in 38.7% of cases. CONCLUSION: Despite improvement in immunization coverage, the study reveals that a large number of children (67.2%) who suffer from poliomyelitis are unvaccinated. This stresses need to intensify and sustain high level of immunization coverage with effective vaccine.     

Primary isolation of Mycobacterium avium complex-serotype 6 on blood agar

Mycobacterium avium complex-serotype 6 was isolated in pure culture on blood agar plates from inocula taken from the heart blood, lungs, liver, kidneys, and spleen of a naturally infected captive female opossum (Didelphis marsupialis virginiana). Repeat cultures from stored tissues and transfer of colonies from original blood agar plates revealed that the mycobacterium grew on tryptose, brilliant green, eosin-methylene blue. Sabouraud glucose, and mycobiotic agar plates and in Fletcher leptospira medium. The cultural, biochemical, and serological characteristics of the test isolate were compared with other mycobacteria. This is the first report to describe the primary isolation of a serotype from the M. avium complex from an animal species on blood agar or in Fletcher broth. In addition, this is the second documented report describing the isolation and identification of a mycobacterial species from the American opossum.     

A state variable approach to digital image processing

Digital filtering of images is considered. A recursive filter design for two-dimensional separable filters is discussed which is based on state variable methods. Advantages of this design are guaranteed stability, and shorter word length than filters designed by bilinear mapping techniques, greater computational efficiency and easier design as compared with nonrecursive filters. Results are shown for filtering high frequency additive noise from a low spatial frequency image and for filtering a low frequency multiplicative noise from a high spatial frequency image.     

Systolic arrays for Viterbi processing in communication systemswith a time-dispersive channel

The theory and design of systolic arrays for Viterbi processing in communication systems with a time-dispersive time-varying channel is discussed. The architecture, algorithms, and processor elements, for a two-dimensional systolic array are described. The array supports the branch metric computations required for an adaptive Viterbi processor. The array is designed so that computations propagate along the rows of the array, while data symbols propagate along the columns. All interprocessor data flow and connections within the array are nearest-neighbor. The array illustrates how the Viterbi-processor algorithms can be structured to achieve a high degree of computational concurrency. Variations in the array design are described and evaluated in terms of computational resource requirements and utilization and computational throughput. A high-bandwidth memory interface is proposed, and system design considerations are discussed     

Determination of minimum cutting tool paths in the presence of barriers

A software package is described that finds a minimum path tour for traveling salesman problems with barriers or obstructions blocking straight line travel. The package contains modules to (1) determine whether or not nodes (destinations) can be connected by straight lines, (2) find the shortest path between pairs of nodes if barriers are present, and (3) compute the minimum tour to visit all nodes and avoid barriers. The user may choose a tour that minimizes distance or minimizes time of travel. The latter assumes constant accelerations and declerations, and steady state tool velocity. Illustrations and sample calculations are presented. The set of algorithms in the software package is a heuristic although some aspects such as the shortest path calculations are optimal.