Processes In Complex Systems Research Articles

On stability and performance of parallel processing systems

The general problem of parallel (concurrent) processing is investigated from a queuing theoretic point of view. As a basic simple model, consider infinitely many processors that can work simultaneously, and a stream of arriving jobs, each carrying a processing time requirement. Upon arrival, a job is allocated to a processor and starts being executed, unless it is blocked by another one already in the system. Indeed, any job can be randomly blocked by any preceding one, in the sense that it cannot start being processed before the one that blocks it leaves. After execution, the job leaves the system. The arrival times, the processing times and the blocking structures of the jobs form a stationary and ergodic sequence. The random precedence constraints capture the essential operational characteristic of parallel processing and allow a unified treatment of concurrent processing systems from such diverse areas as parallel computation, database concurrency control, queuing networks, flexible manufacturing systems. The above basic model includes the G/G/1 and G/G/∞ queuing systems as special extreme cases. Although there is an infinite number of processors, the precedence constraints induce a queuing phenomenon, which, depending on the loading conditions, can lead to stability or instability of the system. In this paper, the condition for stability of the system is first precisely specified. The asymptotic behavior, at large times, of the quantities associated with the performance of the system is then studied, and the degree of parallelism, expressed as the asymptotic average number of processors that work concurrently, is computed. Finally, various design and simulation aspects concerning parallel processing systems are considered, and the case of finite number of processors is discussed. The results proved for the basic model are then extended to cover more complex and realistic parallel processing systems, where each job has a random internal structure of subtasks to be executed according to some internal precedence constriants.

Parallelism and the transputer for real-time high-performance control of AC induction motors

The paper describes the use of a multitransputer system for the implementation of highperformance vector control strategies for AC induction motors. These strategies constitute a complex real-time signal processing system and, as such, highlight the advantages and disadvantages of using parallelism for real-time motor control. The assessment of the transputer performance is felt to be significant, as it is shown that a generalised motor drive control ler exhibits some implicit parallel characteristics within its structure. The extent to which parallelism, and the transputer in particular, should be used for either development or commercial drive systems is therefore discussed.

Energy Optimization Through Exergy-Economic Evaluation

This paper deals with total system optimization for energy use in complex process systems based on the premise that the sub-systems or local schemes have been optimally designed. The problem, however, has not been solved so far. Based on the three-links-model established for the energy structure of process systems, this paper advances an evolving optimization strategy, in which the results of quantitative exergy-economic evaluation of the sub-systems are taken as the criteria to guide trade-off among them and lead the total scheme gradually towards optimum. The general concepts, evaluation equations, applying procedure, and examples are presented. Notable economical and energy-saving benefits can be (have been) obtained when used on actual industrial plants.

Are topographic data sets fractal?

The scale invariant properties of fractal sets make them attractive models for topographic profiles because those profiles are the end product of a complex system of physical processes operating over many spatial scales. If topographic data sets are fractal, their power spectra will be well represented by lines in log-log space with slopess such that −3≤s<−1. The power spectra from a Digital Elevation Model (30 meter sample spacing) of the Sierra Nevada Batholith and from Seabeam center beam depths (425 meter sample spacing) along a flowline in the South Atlantic are curved. Straight sections in the spectra can be identified but the slopes of those sections are strongly dependent upon the particulars of the data analysis. Fractal geometry must be used with caution in the discussion of topographic data sets.

Is today's office receiving full value from its computers?

The office of today makes intensive and extensive use of electronic computers and data processing systems which provide powerful support for a host of realtime and transaction oriented applications essential to the offices' smooth operations. These systems do the work of uncountable “virtual clerks” who are managed by the real, human office and knowledge workers. A cursory examination shows that, in general, offices are doing their job rather well, the work is getting done. Nevertheless, the office of today is still using ADP largely as a tool — ADP is not the office. Not enough attention has been paid to the office's real structure, a complex system of procedural processes. Upon closer examination, many office “horror stories” and “computer goofs” turn out to be flawed or incorrectly executed procedures. Tutorial case examples cited include salary and grade review, realtime program testing, computer security, and bank check clearing operations. A fifth case, an accounts payable system, illustrates the benefits that proper system design and implementation can provide. Office procedures, therefore, are an urgent target for providing computer assistance. By going this route, significant improvements in the office's functionality and performance can be attained, operational costs can be reduced, an improved office environment can be created, and confidence in virtually error-free procedural operations can be restored.

A Study of the Mental Model of a Complex Dynamic System: The Effect of Display Aiding and Contextual System Training

The acquisition of mental models and the effect of instructions and a display aid on the performance on a complex dynamic processing system were examined in this experiment. Thirty subjects monitored a dynamic bar graph display of six system variables and were tested under three different conditions: 1) subjects were given contextual instructions and a picture display-aid which provided a perceptual context in which to interpret the changing variables (group P/B). 2) Subjects were only provided non-context instructions and tested by a bar graph display (group B). 3) A transfer group was trained under the same condition as same as group P/B and tested with the bar graph display (group P/B - B). The data showed that the combination of the context instructions and the meaningful display aid improved subjects' performance significantly. The accuracy of diagnosis of the group P/B was the highest among the three groups. It was also seen that training with the context instructions themselves could improve the accuracy of diagnosis although the difference between the transfer group and group B was not significant statistically.

Phagocytosis of sperm cytoplasmic droplets by a specialized region in the epididymis of the brushtailed possum, Trichosurus vulpecula.

During sperm maturation in the brushtailed possum, Trichosurus vulpecula, cytoplasmic droplets are shed from maturing spermatozoa in the distal regions of the head of the epididymis. Examination of luminal contents from various regions of the epididymis showed that the proportion of detached droplets in the luminal contents was reduced from about 45% in the proximal corpus epididymidis to less than 10% in the distal corpus and cauda epididymides. In contrast, the proportion of droplet-free spermatozoa increased from about 45% to more than 90% in the luminal contents. Disappearance of detached cytoplasmic droplets from the lumen was found to be associated with a region of specialized principal cells lining Regions 6 and 7 of the epididymis which selectively sequester and phagocytose free droplets from the luminal milieu. The luminal surfaces of these cells are characterized by a complex system of interdigitating processes which appear as waves of microfolds . These processes contrast with the stereocilia which cover the luminal surfaces of principal cells in adjacent, nonphagocytic regions of the duct. Cytoplasmic droplets are phagocytosed with their limiting membrane intact and gradually become condensed as they are transported deeper into the cell. Membrane lamellae are gradually compacted, transformed into concentrically arranged membrane stacks and then condensed into small electron-dense vesicles, which are probably degraded by the epithelial cells. The presence of a specific recognition factor on cytoplasmic droplets is suggested by the observation that phagocytic principal cells are able to selectively remove detached cytoplasmic droplets from the lumen in the presence of sperm-associated droplets and spermatozoa.

Heterogeneity of asparagine-linked oligosaccharides of five glycosylation sites on immunoglobulin M heavy chain from mineral oil plasmacytoma 104E.

Mouse myeloma immunoglobulin IgM heavy chains were cleaved with cyanogen bromide into nine peptide fragments, four of which contain asparagine-linked sites of glycosylation. Three of these glycopeptides contain a single site located at asparagines 171, 403, and 563 in the sequence of the intact heavy chain. Another glycopeptide contains two sites of glycosylation at asparagines 332 and 364. All sites contain multiple oligosaccharide structures with a trend towards increased processing from the COOH to the NH2 terminus. Structures present at asparagine 563, located only exclusively high mannose oligosaccharides. Asparagine 403, located penultimate to the COOH terminus, has a major component that is of a complex nature but is incompletely processed. Other sites contain predominantly complex structures consisting of biantennary or triantennary branches. The unusual structure found at asparagine 403 contains fucose even though only one branch has been processed to a terminal galactose. These studies suggest that each site has a unique set of heterogeneous oligosaccharides derived from a complex processing system which utilizes a combination of "position completeness" and polypeptide structure to determine final carbohydrate structure.

Personality as a complex informationprocessing system

One of the major challenges for psychology in the coming decades is to present integrative conceptualizations of various psychological processes (e.g., cognition, values, etc.). The purpose of this paper is to present a system-theoretic conception of the organized complexities of human personality. A complex hierarchical information processing system (CHIPS) is described as a nonrandom organization of subsystems and components among which there is: (a) goal direction; (b) regulation of uncertainty; (c) interdependence; (d) macrodeterminism; and (e) increasing hierarchicalization over the life span. While our focus is at the level of the organism, these characteristics attributed to a CHIPS are considered to be basic characteristics of living systems at all levels. Personality is conceptualized as an integrative composite of six interacting systems (sensory, motor, cognition, affect, style, and value), each of which has these characteristics. Various properties and principles relevant to this conception of integrative personality as a complex system are discussed and illustrated. It is pointed out that modern systems theory has given too little attention to the problem of developmental change, and a metamorphogenetic model of development is proposed and illustrated in the present paper.

Simulation of multicomputer radar systems for ballistic missile defense

Modern missile defense radars involve complex data processing systems with stringent requirements for real-time throughput. To satisfy the peak processing demands of these systems, functions such as searching and tracking can be assigned to separate inter connected computers. However, predicting whether a proposed distributed system will actually satisfy its objectives is difficult because of the complex inter actions. The MULTISIM computer program can simu late multicomputer systems used in radar data process ing and can thereby aid in predicting performance. The simulator models a variety of distributed computer organizations involving central processing units,communications busses, shared memory, and a radar return stream. Both hardware connections and soft ware relationships can be modeled. The analysis of an example distributed computer system shows how results such as the processing time for radar returns, utilization of physical components, and aggregate throughput aid in evaluating proposed designs.

Bootstrapping on the adaptive landscape

Different versions of a gene or of a multigenic system may be essentially equivalent so far as the specific function of the structures which they code for or control is concerned, but very different with respect to their amenability to evolution. The structural features which increase evolutionary amenability are a disadvantage to the organism in terms of energy. Nevertheless, they accumulate in the course of evolution as a consequence of hitchhiking along with the desirable traits whose evolution they make possible. This is the bootstrap principle of evolutionary adaptability. In terms of the adaptive landscape bootstrapping corresponds to populations evolving in such a way that they occupy regions of the landscape which are more amenable to evolutionary hill climbing. The bootstrapping idea has implications for structure-function relations in a number of complex biological information processing systems, including biochemical systems, the immune system, and the brain. Bootstrapping is also discussed in connection with the origin of information processing (the origin of life) and in connection with possible designs for macromolecular computing systems.

Bit-slice microprocessors—their use and application in minicomputers

Although the effort necessary to develop an effective bit-slice-microprocessor microprogrammed design initially seems significant, the benefits far outweigh the investment. After microprogramming techniques are developed, new applications become much easier to accomplish. Although a designer may have to learn new methods, once mastered, a very powerful design tool can be applied to solving complex data processing or control communication systems

Thermodynamic availability analysis in the synthesis and analysis of complex processing systems

A steady state flow system which undergoes physical and chemical transformations can be analyzed thermodynamically in terms of its availability change, for the ideal case. In an actual case reversibility is not accomplished and the system energetic performance can be judged in terms of the irreversible creation of entropy. This analysis results in an upper and lower bound, respectively. The lower bound is evolutionary in nature. Large interactive processing systems can be described in terms of a linear programming model. By setting as objectives either the maximization of change in thermodynamic availability or the minimization of irreversible creation of entropy, it is possible to select the set of technologies which defines the bounding optimum structure of the system considered.

A Markovian Model for Processing Systems with Imperfect Review

Abstract This paper presents a unified linear Markovian analysis of complex processing systems with imperfect review. The model is not only applicable to traditional quality control operations but also to systems processing reports or schedules whose quality can be measured discretely. The analysis goes beyond the more traditional approaches by modeling imperfect inspection, addressing the output quality-workload tradeoff and defining transient response to feedback systems. The model itself uses three basic stages, an operational one which allows changes in the discrete error-level of a product, a branching one which allows dispersion of the incoming product based on the number of defects observed and a merging one which allows for the converging of products from different sources. By introducing two special matrices, the resulting analysis is quite simple even for the transient response to complicated feedback systems. This ease of analysis is particularly useful in sensitivity evaluations and considerat...

Ultrastructure of a colonial radiolarian Collozoum inerme and a cytochemical determination of the role of its zooxanthellae

Collozoum inerme (Müller) is a colonial Radiolarian containing numerous cells bound in a common gelatinous matrix. The cells do not possess a skeleton as observed in many unicellular Radiolaria, but the cytoplasmic organization is similar. The cells are multinucleate and a complex system of cellular processes containing mitochondria, Golgi, and numerous vacuoles radiate out from the nuclear region. The endoplasm is connected to the ectoplasm across a double membrane boundary by thin cytoplasmic strands called fusules whose structure resemble those in unicellular Radiolaria. The ectoplasm contains a lacy network of vacuoles containing an osmiophilic substance. Rhizopodia emerge from the ectoplasmic sheath. Some are thin and densely granular. Larger diameter rhizopodia, containing less dense cytoplasm, sequester the zooxanthellae which present a typical dinoflagellate fine structure. Some of the zooxanthellae are apparently cultivated since they are sometimes observed dividing and persist in large numbers when colonies are cultivated under illumination for several weeks in the laboratory. However, colonies maintained in the dark have a decline in number of zooxanthellae and light microscopic examination shows they are being drawn into the ectoplasm of the radiolarian cells. Electron microscopic examination of zooxanthellae drawn into the ectoplasm sheath indicates they are digested. C. inerme is a remarkable example of a simple cellular aggregate that has exploited its colonial habit to culture algae and use them as food thus possibly enhancing the viability of the colony.

Computer Programs for Absorption Spectrophotometry

Brief descriptions are given of twenty-two modular computer programs for performing the basic numerical computations of absorption spectrophotometry. The programs, written in Fortran IV for card input and output, are available from the National Research Council of Canada. The input and output formats are standardized to permit easy interfacing to yield more complex data processing systems. Though these programs were developed for ir spectrophotometry, they are readily modified for use with digitized visual and uv spectrophotometers. The operations covered include ordinate and abscissal unit and scale interconversions, ordinate addition and subtraction, location of band maxima and minima, smoothing and differentiation, slit function convolution and deconvolution, band profile analysis and asymmetry quantification, Fourier transformation to time correlation curves, multiple overlapping band separation in terms of Cauchy (Lorentz), Gauss, Cauchy-Gauss product, and Cauchy-Gauss sum functions and cell path length determination from fringe spacing analysis.

Experience in Processing Core Analysis and Production Data with a Digital Computer

Abstract In 1959 Imperial Oil Limited began using an IBM-705 computer for reductionof core analysis data and for calculation of capacity distributions. In thefirst study, relatively small volumes of data were processed, and manualmethods were used to correct input data and to check computer output. It wasapparent that for larger studies it would be necessary to write additionalprograms, to sort, edit, and update input data, and to summarize output. Early in 1960 a start was made computer processing of production andinjection histories. Using experience gained in dealing with large volumes ofcore analysis information, an integrated system of programs was first developedto generate accurate master data files. Extreme care in original planning mustbe exercised to obtain an efficient operation. Evolutionary build up of a dataprocessing system is technically difficult and wasteful of both manpower andmachine time. Introduction Processing of core analysis and production data with a digital computerinvolves a multitude of simple calculations which would otherwise be performedusing desk machines. Computers are used to improve accuracy, and to facilitateprocessing large volumes of data. The accuracy of computer calculations is, of course, directly dependent onthe accuracy of the input data. Once reliable input data records have beencompiled on tape, it is possible to carry out further reservoir engineeringcomputations. Master data tapes should carry sufficient information to satisfyall foreseeable future requirements. Two fairly complex data processing systems have been developed by ImperialOil Limited to process production and core analysis data. The core analysissystem is used primarily to obtain averages of reservoir parameters and todefine stratification. The production system is used mainly to calculate dailyand cumulative production rates, and gas or water-oil ratios, for single wellsor groups of wells.

Automatic Failure Recovery in a Digital Data Processing System

This paper describes a program which will enable a complex digital data processing system to give first aid to itself. Ordinarily, when an error occurs during system operations, the computer must be stopped for corrective maintenance. The FIX program, however, automatically compensates for computer malfunctions so that recovery from errors may be effected with a negligible loss of operational time. Some equipment features used by the FIX program are briefly outlined prior to a detailed discussion of the structure and function of the program itself. In its initial application in the SAGE system, FIX provided automatic recovery from more than 90% of all failures occurring during the period studied.

Allen Newell and Herbert A. Simon. The logic theory machine. A complex information processing system. Institute of Radio Engineers, Transactions on information theory, vol. IT-2 no. 3 (1956), pp. 61–79.

Allen Newell and Herbert A. Simon. The logic theory machine. A complex information processing system. Institute of Radio Engineers, Transactions on information theory, vol. IT-2 no. 3 (1956), pp. 61–79. - Volume 22 Issue 3

The logic theory machine--A complex information processing system

In this paper we describe a complex information processing system, which we call the logic theory machine, that is capable of discovering proofs for theorems in symbolic logic. This system, in contrast to the systematic algorithms that are ordinarily employed in computation, relies heavily on heuristic methods similar to those that have been observed in . human problem solving activity. The specification is written in a formal language, of the nature of a pseudo-code, that is suitable for coding for digital computers. However, the present paper is concerned exclusively with specification of the system, and not with its realization in a computer. The logic theory machine is part of a program of research to understand complex information processing systems by specifying and synthesizing a substantial variety of such systems for empirical study.