Showing papers by "University of Illinois at Urbana–Champaign published in 1989"
TL;DR: It is demonstrated that finite linear combinations of compositions of a fixed, univariate function and a set of affine functionals can uniformly approximate any continuous function ofn real variables with support in the unit hypercube.
Abstract: In this paper we demonstrate that finite linear combinations of compositions of a fixed, univariate function and a set of affine functionals can uniformly approximate any continuous function ofn real variables with support in the unit hypercube; only mild conditions are imposed on the univariate function. Our results settle an open question about representability in the class of single hidden layer neural networks. In particular, we show that arbitrary decision regions can be arbitrarily well approximated by continuous feedforward neural networks with only a single internal, hidden layer and any continuous sigmoidal nonlinearity. The paper discusses approximation properties of other possible types of nonlinearities that might be implemented by artificial neural networks.
12,286 citations
01 Apr 1989
TL;DR: The author proceeds with introductory modeling examples, behavioral and structural properties, three methods of analysis, subclasses of Petri nets and their analysis, and one section is devoted to marked graphs, the concurrent system model most amenable to analysis.
Abstract: Starts with a brief review of the history and the application areas considered in the literature. The author then proceeds with introductory modeling examples, behavioral and structural properties, three methods of analysis, subclasses of Petri nets and their analysis. In particular, one section is devoted to marked graphs, the concurrent system model most amenable to analysis. Introductory discussions on stochastic nets with their application to performance modeling, and on high-level nets with their application to logic programming, are provided. Also included are recent results on reachability criteria. Suggestions are provided for further reading on many subject areas of Petri nets. >
10,755 citations
TL;DR: In this article, a discussion about steps involved in developing a theory, such as seeing which factors logically should be considered as part of the explanation of the social or individual phenomena of interest, is presented.
Abstract: The article focuses on the development of a theory. A discussion is presented about steps involved in developing a theory, such as seeing which factors logically should be considered as part of the explanation of the social or individual phenomena of interest. The authors assert that authors developing theories are considering these factors, they should err in favor of including too many factors, recognizing that over time their ideas will be refined. The article presents information about the importance of sensitivity to the competing virtues of parsimony and comprehensiveness.
3,224 citations
TL;DR: The results support the conclusion that a critical period for language acquisition extends its effects to second language acquisition.
2,490 citations
TL;DR: In this paper, a control law for teleoperators is presented which overcomes the instability caused by time delay by using passivity and scattering theory, a criterion is developed which shows why existing bilateral control systems are unstable for certain environments, and why the proposed bilateral control law is stable for any environment and any time delay.
Abstract: A control law for teleoperators is presented which overcomes the instability caused by time delay. By using passivity and scattering theory, a criterion is developed which shows why existing bilateral control systems are unstable for certain environments, and why the proposed bilateral control law is stable for any environment and any time delay. The control law has been implemented on a single-axis force-reflecting hand controller, and preliminary results are shown. To keep the presentation clear, a single-degree-of-freedom (DOF) linear time-invariant (LTI) teleoperator system is discussed. Nevertheless, results can be extended, without loss of generality, to an n-DOF nonlinear teleoperation system. >
2,131 citations
TL;DR: The LISREL VI computer program was employed to conduct a confirmatory factor analysis to assess the tenability of a five factor hierarchical model representing four first-order factors or dimensions and a second-order general factor representing intrinsic motivation as mentioned in this paper.
Abstract: The present study was designed to assess selected psychometric properties of the Intrinsic Motivation Inventory (IMI) (Ryan, 1982), a multidimensional measure of subjects' experience with regard to experimental tasks. Subjects (N = 116) competed in a basketball free-throw shooting game, following which they completed the IMI. The LISREL VI computer program was employed to conduct a confirmatory factor analysis to assess the tenability of a five factor hierarchical model representing four first-order factors or dimensions and a second-order general factor representing intrinsic motivation. Indices of model acceptability tentatively suggest that the sport data adequately fit the hypothesized five factor hierarchical model. Alternative models were tested but did not result in significant improvements in the goodness-of-fit indices, suggesting the proposed model to be the most accurate of the models tested. Coefficient alphas for the four dimensions and the overall scale indicated adequate reliabilit...
2,050 citations
TL;DR: The Working Alliance Inventory (WAI) as discussed by the authors was completed after the 1st psychotherapy session by 84 university counseling center clients and 15 therapists rating their work with 123 clients, and was used to assess therapists' work with their clients.
Abstract: The Working Alliance Inventory (WAI) was completed after the 1st psychotherapy session by 84 university counseling center clients and 15 therapists rating their work with 123 clients
1,457 citations
TL;DR: SME has been built to explore Gentner's structure-mapping theory of analogy, and provides a "tool kit" for constructing matching algorithms consistent with this theory, making it a useful component in machine learning systems as well.
1,336 citations
TL;DR: In this article, the authors explore how the mental models of organizational strategists determine perceptions of competing organizations and responses to competitive conditions and conclude that the structure of that industry both determines and is determined by managerial perceptions of the environment.
Abstract: This article explores how the mental models of organizational strategists determine perceptions of competing organizations and responses to competitive conditions. We first outline a cognitive perspective for discussing competitive strategy, and then use this framework to analyse the particular case of the Scottish knitwear industry. We show how the structure of that industry both determines and is determined by managerial perceptions of the environment. We conclude by drawing out a few general implications of our framework for research and theory on competitive strategy.
1,329 citations
TL;DR: The intent is to lend some perspective to the growing list of adaptive control results for manipulators by providing a unified framework for comparison of those adaptive control algorithms which have been shown to be globally convergent.
1,212 citations
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01 Jan 1989TL;DR: In this article, a table comparing additional income blacks and whites can expect for each additional year of education is presented, which is as interesting in its own right as any dinosaur bone or photo of Saturn.
Abstract: A core interest of social science is the study of stratification--inequalities in income, power, and prestige. Few persons would care about such inequalities if the poor, powerless, and despised were as happy and fulfilled as the wealthy, powerful, and admired. Social research often springs from humanistic empathy and concern as much as from scholarly and scientific curiosity. An economist might observe that black Americans are disproportionately poor, and investigate racial differences in education, employment, and occupation that account for disproportionate poverty. A table comparing additional income blacks and whites can expect for each additional year of education is thus as interesting in its own right as any dinosaur bone or photo of Saturn. However, something more than curiosity underscores our interest in the table. Racial differences in status and income are a problem in the human sense. Inequality in misery makes social and economic inequality personally meaningful. There are two ways social scientists avoid advocacy in addressing issues of social stratification. The first way is to resist projecting personal beliefs, values, and responses as much as possible, while recognizing that the attempt is never fully successful. The second way is by giving the values of the subjects an expression in the research design. Typically, this takes the form of opinion or attitude surveys. Researchers ask respondents to rate the seriousness of crimes, the appropriateness of a punishment for a crime, the prestige of occupations, the fair pay for a job, or the largest amount of money a family can earn and not be poor, and so on. The aggregate judgments, and variations in judgments, represent the values of the subjects and not those of the researcher. They are objective facts with causes and consequences of interest in their own right. This work is an effort to move methodology closer to human concerns without sacrificing the scientific grounds of research as such. The authors succeed admirably in this complex and yet worthwhile task. This is a work that could be helpful to those in all branches of the social sciences that take up issues relating to inequality and the uneven distribution of the social goods of a nation.
01 Jan 1989
TL;DR: In this paper, the fundamental nature of the internal stresses that are found in both evaporated and sputtered coatings is reviewed from the point of view of decorative coating applications, which indicate that apparatus geometry is particularly important in determining the state of stress that forms in deposits.
TL;DR: A theoretical model of person memory that incorporates both types of information about a person that accounts for a large number of factors that are known to affect the recall of social information, the making of interpersonal judgments, and the relation between what is recalled and the judgments that are made.
Abstract: Two general types of information about a person are considered in this article: One pertains to specific behaviors a person has manifested, and the other refers to more abstract personality dispositions or behavioral tendencies. A theoretical model of person memory that incorporates both types of information is developed. The model accounts for a large number of factors that are known to affect the recall of social information, the making of interpersonal judgments, and the relation between what is recalled and the judgments that are made. A major strength of the model is its applicability to a wide range of person memory and judgment phenomena that are observed in several different experimental paradigms.
TL;DR: The issues of choice of stochastic-process model and computation of efficient designs are addressed, and applications are made to some chemical kinetics problems.
Abstract: A computer experiment generates observations by running a computer model at inputs x and recording the output (response) Y. Prediction of the response Y to an untried input is treated by modeling the systematic departure of Y from a linear model as a realization of a stochastic process. For given data (selected inputs and the computed responses), best linear prediction is used. The design problem is to select the inputs to predict efficiently. The issues of choice of stochastic-process model and computation of efficient designs are addressed, and applications are made to some chemical kinetics problems.
TL;DR: The claim that critical thinking is subject specific appears, to be of practical importance and theoretical interest as discussed by the authors. But its meaning is unclear, and discussions of its are often confusing and at cross purposes.
Abstract: The claim that critical thinking is subject specific appears, to be of practical importance and theoretical interest. Its meaning is unclear, however, and discussions of its are often confusing and at cross purposes. In an attempt to clarify the topic, Ennis offers a number of distinctions, including a distinction among three versions of subject specificity: domain, epistemological, and conceptual subject specificity. He holds that the first two versions contain valuable insights, but that all three suffer from excessive vagueness of their basic concept (domain, field, and subject, respectively). If the proposed clarification and critique are appropriate, then a number of avenues of research—at both practical and theoretical levels—need to be pursued, some of which are outlined in this essay
TL;DR: The actual and potential benefits of a marriage between cognitive psychology and psychophysiology are reviewed and the lateralized readiness potential, a measure of electrical brain activity that is related to preparation for movement, is reviewed.
Abstract: This paper reviews the actual and potential benefits of a marriage between cognitive psychology and psychophysiology. Psychophysiological measures, particularly those of the event-related brain potential, can be used as markers for psychological events and physiological events. Thus, they can serve as "windows" on the mind and as "windows" on the brain. These ideas are illustrated in the context of a series of studies utilizing the lateralized readiness potential, a measure of electrical brain activity that is related to preparation for movement. This measure has been used to illuminate presetting processes that prepare the motor system for action, to demonstrate the presence of the transmission of partial information in the cognitive system, and to identify processes responsible for the inhibition of responses. The lateralized readiness potential appears to reflect activity in motor areas of cortex. Thus, this measure, along with other psychophysiological measures, can be used to understand how the functions of the mind are implemented in the brain.
TL;DR: Small-subunit rRNA sequences were determined for almost 50 species of mycoplasmas and their walled relatives, providing the basis for a phylogenetic systematic analysis of these organisms.
Abstract: Small-subunit rRNA sequences were determined for almost 50 species of mycoplasmas and their walled relatives, providing the basis for a phylogenetic systematic analysis of these organisms. Five groups of mycoplasmas per se were recognized (provisional names are given): the hominis group (which included species such as Mycoplasma hominis, Mycoplasma lipophilum, Mycoplasma pulmonis, and Mycoplasma neurolyticum), the pneumoniae group (which included species such as Mycoplasma pneumoniae and Mycoplasma muris), the spiroplasma group (which included species such as Mycoplasma mycoides, Spiroplasma citri, and Spiroplasma apis), the anaeroplasma group (which encompassed the anaeroplasmas and acholeplasmas), and a group known to contain only the isolated species Asteroleplasma anaerobium. In addition to these five mycoplasma groups, a sixth group of variously named gram-positive, walled organisms (which included lactobacilli, clostridia, and other organisms) was also included in the overall phylogenetic unit. In each of these six primary groups, subgroups were readily recognized and defined. Although the phylogenetic units identified by rRNA comparisons are difficult to recognize on the basis of mutually exclusive phenotypic characters alone, phenotypic justification can be given a posteriori for a number of them.
TL;DR: The initial version of the scale was administered to 407 men and 207 women at intake into a domestic violence program, and the agreement of men's and women’s reports was low, though the scores on the domination-isolation subscale were significantly correlated.
Abstract: This study describes the initial development of a scale of measurement of psychological maltreatment of women by their male partners. The initial version of the scale was administered to 407 men and 207 women at intake into a domestic violence program. All 58 items of the scale were endorsed by a large enough number of subjects to warrant inclusion in the final instrument. Factor analysis revealed a similar factor structure for the men and women, with dominance-isolation and emotional-verbal abuse factors emerging from the analysis. Intracouple reliability for each item of the scale was examined for the subset of men and women who were cohabiting couples (n = 28). Unsurprisingly, the agreement of men's and women's reports was low, though the scores on the domination-isolation subscale were significantly correlated.
TL;DR: The electron system is found to be in the normal- (paramagnetic) fluid state below the transition density, but the fully polarized state is very close in energy.
Abstract: Variational and fixed-node Green's-function Monte Carlo calculations have been performed to find the ground-state properties of the two-dimensional electron gas in the density range 1\ensuremath{\le}${r}_{s}$\ensuremath{\le}100. Our calculations predict a Wigner crystallization at the density ${r}_{s}$\ensuremath{\simeq}37\ifmmode\pm\else\textpm\fi{}5. The electron system is found to be in the normal- (paramagnetic) fluid state below the transition density, but the fully polarized state is very close in energy. We have tabulated the values of pair distribution function g(r), the static structure factor S(k), and the momentum distribution n(k) at several densities of interest both in the normal and the polarized phases. An estimate of the spin susceptibility \ensuremath{\chi} is also given.
TL;DR: The authors found that Hispanics exhibit a stronger tendency for extreme checking (about half the time, on the average) than non-Hispanic, but only when the 5-point scales were used.
Abstract: Do cultural and ethnic groups differ in their extreme response style? To answer this question, Hispanic and non-Hispanic subjects were asked to respond to a questionnaire on 5-point or 10-point scales. As predicted, Hispanics were found to exhibit a stronger tendency for extreme checking (about half the time, on the average) than non-Hispanic, but only when the 5-point scales were used. Use of 10-point scales reduced the extreme responses of the Hispanics to the level of non-Hispanics. Extreme responses of non-Hispanics were not affected by the scales. Implications of the findings for social research are discussed.
TL;DR: The results support the existence of long-range antiferromagnetic order in the ground state at half-Filling and its absence at quarter-filling and find evidence for an attractive effective /ital d/-wave pairing interaction near half- filling but have not found evidence for a phase transition to a superconducting state.
Abstract: We report on a numerical study of the two-dimensional Hubbard model and describe two new algorithms for the simulation of many-electron systems. These algorithms allow one to carry out simulations within the grand canonical ensemble at significantly lower temperatures than had previously been obtained and to calculate ground-state properties with fixed numbers of electrons. We present results for the two-dimensional Hubbard model with half- and quarter-filled bands. Our results support the existence of long-range antiferromagnetic order in the ground state at half-filling and its absence at quarter-filling. Results for the magnetic susceptibility and the momentum occupation along with an upper bound to the spin-wave spectrum are given. We find evidence for an attractive effective d-wave pairing interaction near half-filling but have not found evidence for a phase transition to a superconducting state.
National Institutes of Health1, University of North Carolina at Chapel Hill2, New York University3, University of Michigan4, University of Texas Southwestern Medical Center5, Vanderbilt University6, University of Illinois at Urbana–Champaign7, Scripps Research Institute8, Hoffmann-La Roche9, Queen Mary University of London10, Osaka University11
TL;DR: A modest revision of the initially proposed nomenclature of the P450 superfamily is described specifically for the human and mouse chromosomal loci, with the root symbol "CYP" for human ("Cyp" for mouse), denoting "cytochrome P450."
Abstract: In this update we provide a list of the 71 P450 genes and the four P450 pseudogenes that have been characterized as of September 30, 1988. The chromosomal locations of many of these genes are also summarized. A modest revision of the initially proposed nomenclature of the P450 superfamily (Nebert et al., DNA 6, 1–11, 1987) is described specifically for the human and mouse chromosomal loci. The motivation for this revision is to conform to the rules of nomenclature for human and mouse genes. Recommendations for the naming of chromosomal loci include the root symbol "CYP" for human ("Cyp" for mouse), denoting "cytochrome P450." We recommend that this root also be used for other organisms. For a chromosomal locus, the root symbol is followed by an Arabic numeral designating the P450 family, a letter indicating the sub-family, and an Arabic numeral representing the individual gene within the family or subfamily. Numbers of the individual genes usually will be assigned in the order the genes are ident...
26 Jun 1989
TL;DR: Averaging theory as discussed by the authors offers constructive tools for the analysis of oscillatory ordinary differential equations with time-discontinuous right-hand sides, if requirements of solution differentiability are relaxed.
Abstract: Averaging theory offers constructive tools for the analysis of oscillatory ordinary differential equations with time-discontinuous right-hand sides, if requirements of solution differentiability are relaxed. This theory forms a rigorous framework for evaluating, refining, and extending heuristic averaged models used in power electronics, and provides direct techniques for recovering oscillatory effects such as ripple from the averaged model. An overview of this theory is presented, and DC-DC converters are analyzed as examples. >
TL;DR: In this article, a class of coupled map lattices is investigated as a model for the spatiotemporal chaos, and pattern selection through the chaotic motion of domain is observed, where localized defects which separate the two anti-phase domains are found.
TL;DR: Experimental and clinical studies demonstrate that both laboratory and natural stressors alter the activities of lymphocytes and macrophages in a complex way that depends on the type of immune response, the physical and psychological characteristics of the stressor and the timing of stress relative to the induction and expression of the immune event.
TL;DR: The authors compared the effectiveness of dialectical inquiry, devil's advocacy, and consensus approaches to strategic planning in a longitudinal laboratory study of fast-advancing middle managers involved in strategic planning.
Abstract: This longitudinal laboratory study of fast-advancing middle managers involved in strategic planning compared the effectiveness of dialectical inquiry, devil's advocacy, and consensus approaches to ...
TL;DR: The presented approach to error estimation applies to a wide variety of problems that involve least-squares optimization or pseudoinverse and shows, among other things, that the errors are very sensitive to the translation direction and the range of field view.
Abstract: Deals with estimating motion parameters and the structure of the scene from point (or feature) correspondences between two perspective views. An algorithm is presented that gives a closed-form solution for motion parameters and the structure of the scene. The algorithm utilizes redundancy in the data to obtain more reliable estimates in the presence of noise. An approach is introduced to estimating the errors in the motion parameters computed by the algorithm. Specifically, standard deviation of the error is estimated in terms of the variance of the errors in the image coordinates of the corresponding points. The estimated errors indicate the reliability of the solution as well as any degeneracy or near degeneracy that causes the failure of the motion estimation algorithm. The presented approach to error estimation applies to a wide variety of problems that involve least-squares optimization or pseudoinverse. Finally the relationships between errors and the parameters of motion and imaging system are analyzed. The results of the analysis show, among other things, that the errors are very sensitive to the translation direction and the range of field view. Simulations are conducted to demonstrate the performance of the algorithms and error estimation as well as the relationships between the errors and the parameters of motion and imaging systems. The algorithms are tested on images of real-world scenes with point of correspondences computed automatically. >
TL;DR: In this paper, Oriani's equilibrium theory is used to relate the hydrogen in traps (micro-structural defects) to concentration in normal interstitial lattice sites (NILS), and the resulting non-linear transient hydrogen diffusion equations are integrated using a modified backward Euler method.
Abstract: T he hydrogen transport problem is studied in conjunction with large deformation elastic—plastic behavior of a material. Oriani's equilibrium theory is used to relate the hydrogen in traps (micro-structural defects) to concentration in normal interstitial lattice sites (NILS). The resulting non-linear transient hydrogen diffusion equations are integrated using a modified backward Euler method. Coupled diffusion and plastic straining is analysed with this numerical procedure in the area around a blunting crack tip. A uniform NILS concentration as dictated by Sievert's law at the pressure and temperature of interest is used as initial condition throughout the body. The crack is initially blunted by plane strain mode I (tensile) loading. The finite element results show that hydrogen residing at NILS is generally very small in comparison with the population that develops in trapping sites near the crack surface. That is, lattice diffusion delivers the hydrogen but it is predominantly the trapping that determines its distribution at temperatures of interest. The predominance of trapped hydrogen over lattice concentration prevails even in the case when hydrogen migrates under steady state conditions. Hence, the hydrostatic stress effect is less important than traps created by plastic straining as far as the creation of high total hydrogen concentration is concerned. The trapping site locations and the temperature determine the amounts and locations of high hydrogen concentrations. Consequently, ahead of a blunting crack tip, the total hydrogen concentration and plastic strain diminish with distance from the crack tip whereas the hydrostatic stress rises. This would seem to have significant consequences for fractures induced by the presence of hydrogen.