Showing papers by "Northwestern University published in 1981"

Evaluating Structural Equation Models with Unobservable Variables and Measurement Error

Abstract: The statistical tests used in the analysis of structural equation models with unobservable variables and measurement error are examined. A drawback of the commonly applied chi square test, in addit...

Structural Equation Models with Unobservable Variables and Measurement Error: Algebra and Statistics:

Abstract: Several issues relating to goodness of fit in structural equations are examined. The convergence and differentiation criteria, as applied by Bagozzi, are shown not to stand up under mathematical or...

Full-potential self-consistent linearized-augmented-plane-wave method for calculating the electronic structure of molecules and surfaces: O 2 molecule

Abstract: The linearized-augmented-plane-wave (LAPW) method for thin films is generalized by removing the remaining shape approximation to the potential inside the atomic spheres. A new technique for solving Poisson's equation for a general charge density and potential is described and implemented in the film LAPW method. In the resulting full-potential LAPW method (FLAPW), all contributions to the potential are completely taken into account in the Hamiltonian matrix elements. The accuracy of the method---already well known for clean metal surfaces---is demonstrated for the case of a nearly free (noninteracting) ${\mathrm{O}}_{2}$ molecule which is a severe test case of the method because of its large anisotropic charge distribution. Detailed comparisons show that the accuracy of the FLAPW results for ${\mathrm{O}}_{2}$ exceeds that of existing state-of-the-art local-density linear-combination-of-atomic-orbitals (LCAO)-type calculations, and that taking the full potential LAPW results as a reference, the LCAO basis can be improved by adding off-site functions. Thus the full-potential LAPW is a unified method which is ideally suited to test not only molecular adsorption on surfaces, but also the components of the same system separately, i.e., the extreme limits of the molecule and the clean surface.

A uniform strain hexahedron and quadrilateral with orthogonal hourglass control

Abstract: The treatment of zero energy modes which arise due to one-point integration of first-order isoparametric finite elements is addressed A method for precisely isolating these modes for arbitrary geometry is developed Two hourglass control schemes, viscous and elastic, are presented and examined In addition, a convenient one-point integration scheme which analytically integrates the element volume and uniform strain modes is presented

A Micromechanical Description of Granular Material Behavior

Abstract: Considered is a sample of cohesionless granular material, in which the individual granules are regarded rigid, and which is subjected to overall macroscopic average stresses. On the basis of the principle of virtual work, and by an examination of the manner by which adjacent granules transmit forces through their contacts, a general representation is established for the macroscopic stresses in terms of the volume average of the (tensorial) product of the contact forces and the vectors which connect the centroids of adjacent contacting granules. Then the corresponding kinematics is examined and the overall macroscopic deformation rate and spin tensors are developed in terms of the volume average of relevant microscopic kinematical variables. As an illustration of the application of the general expressions developed, two explicit macroscopic results are deduced: (1) a dilatancy equation which both qualitatively and quantitatively seems to be in accord with experimental observation, and (2) a noncoaxiality equation which seems to support the vertex plasticity model. Since the development is based on a microstructural consideration, all material coefficients entering the results have well-defined physical interpretations.

The Multiple Socialization Of Organization Members

Abstract: An integrated model is presented of three relatively distinct views of organizational socialization: the development of work skills and abilities; the acquisition of a set of appropriate role behaviors; and the adjustment to the work group's norms and values. A theoretical rationale is developed to explain the contingencies on which progress through the different socialization processes depend. Three attitudinal variables (general satisfaction, internal work motivation, job development) and three behavioral variables (carrying out role assignments dependably, remaining with the organization, innovation/spontaneous cooperation) are suggested as criteria for measuring progress in socialization.

Social desirability response bias in self-report choice situations.

Abstract: The susceptibility to social desirability response bias of four alternative methods of measuring the importance of job and organizational characteristics is examined. Data were collected from 86 gr...

Judgment of Covariation by Social Perceivers

Abstract: Knowledge about relationships between events is a critical aspect of human knowledge. Knowing whether events are related, and how strongly they are related, enables individuals to explain the past, control the present, and predict the future. Consequently people's ability to judge covariations between events is of central importance to a number of psychological theories. In 1967 Peterson and Beach reviewed people's ability to use correlational concepts, as part of a paper on "Man as an intuitive statistician." At the time of their review, studies on this topic were few in number and not very definitive in the information they provided. Since that time a sizable body of research on intuitive covariation concepts has developed. A substantial amount of research indi

Intepreting Consumer Mythology: A Structural Approach to Consumer Behavior:

Abstract: Consumer behavior depth interviews are grouped with other kinds of story telling—fairy tales, novels, psychological test responses, and myths—as imaginative statements that can be qualitatively int...

A Hierarchical Objective Set Covering Model for Emergency Medical Service Vehicle Deployment

Abstract: The use of hierarchical and multiobjective programming in public decision making is reviewed. The conventional set covering CSC problem is formulated for locating emergency medical service EMS vehicles. Its computational and practical limitations are discussed. The desire to account for inter-district responses leads to the formulation of a hierarchical objective set covering HOSC problem in which we find the minimum number of vehicles needed to cover all zones while simultaneously maximizing the extent of multiple coverage of zones. Several important properties of the HOSC problem are derived, including the fact that for certain values of the relative weights associated with the two objectives, no dominated zones are included in the solution. The CSC and HOSC formulations are applied to a 33-zone problem for Austin, Texas, and computational experiences are indicated.

The influence of outcomes and procedures on satisfaction with formal leaders.

Abstract: Northwestern University In this article, data collected in four studies—two experiments and two surveys— were used to test the hypothesis that the procedures used by leaders to allocate outcomes have an impact on leadership evaluations that is independent of outcome level or outcome fairness. Two studies tested this hypothesis within the context of student evaluations of teachers, and two tested it within the context of citizen evaluations of political leaders. The procedural justice hypothesis was strongly supported by all four studies. In each study, strong procedural influences on evaluation were found, influences that were independent of outcome level or outcome fairness. In addition, in both surveys of naturally occurring evaluations, variations in procedural fairness had a much greater impact on leadership endorsement than did variations in outcome level, outcome satisfaction, or outcome fairness. These findings suggest that in experimental settings subjects can be sensitive to both outcomes and procedures. In natural settings, however, individuals focus on procedures rather than outcomes in forming their evaluations of leaders. Research on outcome satisfaction has been dominated by a concern with the direct and indirect effects of outcomes on outcome satisfaction. Researchers who have followed a social exchange perspective (Homans, 1974; Thibaut & Kelley, 1959) have assumed that an individual's satisfaction with outcomes in a group is directly related to the absolute or relative level of outcomes received, whereas the literature on distributive justice has suggested that outcome satisfaction is an indirect result of outcome level through judgments of outcome fairness (Adams, 1965; Walster, Berscheid, & Walster, 1973; Walster, Walster, & Berscheid, 1978). This same focus on outcomes has also been found in research on satisfaction with group leaders. Research on leadership endorsement has been dominated by work on the influence of group outcomes on the evaluation of group leaders (Hollander & Julian, 1970; Julian, Hollander, & Regula, 1969), work recently supplemented by a concern

Strategy-Proof Allocation Mechanisms at Differentiable Points

Abstract: Consider allocation mechanisms that are single valued and where each agent's strategy space is a set of a priori admissible utility functions Such an allocation mechanism is strategy-proof if, for each agent, faithfully reporting his true utility function is a dominant strategy The purpose of this paper is to characterize for the restricted domains associated with economic environments strategy-proof allocation mechanisms at points at which they are differentiable with respect to agents' preferences Our concern with classical economic environments dictates a framework in which (a) the set of attainable alternatives is a subset of a i-dimensional Euclidean space, (b) the domain of admissible preference n -tuples is restricted (utility functions may be required to satisfy such properties as continuity, monotonicity, and quasiconcavity), and (c) the standard representations of economies are admissible; in particular, the analysis applies to economies with and without production, with and without public goods, and with and without externalities Indeed, our goal has been to provide a result on strategy-proofness that is as basic for allocation mechanisms within economic environments as the Gibbard-Satterthwaite Theorem (Gibbard 1973 and Satterthwaite 1975) is for voting procedures with unrestric

Data broadcasting in SIMD computers

Abstract: Considers the data broadcasting problem for single instruction stream, multiple data stream (SIMD) computers. Two versions of this problem, i.e., random access read (RAR) and random access write (RAW) are considered. Efficient data broadcasting algorithms are developed for both cases. For the case of a RAR, the complexity of the algorithm is O(q2n) on a q-dimensional nq PE mesh-connected computer and 0(log2N) on an N PE cube-connected or perfect shuffle computer. For the case of a RAW, the complexity of the algorithm is 0(q2n+dqn) on a q-dimensional MCC and 0(log2N+d log N) on an N PE cube-connected or perfect shuffle computer; d is the maximum number of data items written into any one PE.

Soil PH, Bone Preservation, and Sampling Bias at Mortuary Sites

Abstract: Prediction of human skeletal preservation at mortuary sites is important in archaeological research and in cultural resources management. In this study, correlations between osseous deterioration and soil acidity, as measured by pH, were found to be significant. Age-associated preservation biases were also evident. The use of multiple regression is suggested as a technique for estimating recovery of human osteological remains in archaeological context.

Analysis of Chordal Ring Network

Abstract: A family of regular graphs of degree 3, called Chordal Rings, is presented as a possible candidate for the implementation of a local network of message-connected (micro) computers. For a properly constructed graph in this family having n nodes the diameter, or maximum length message path, is shown to be of 0(n 1/2). The symmetry of the graphs makes it possible to determine message routing by using a simple distributed algorithm. The given algorithm is also potentially useful for the determination of alternate paths in the event of node or link failure.

Neural Control of Muscle Length and Tension

Abstract: The sections in this article are: 1 Control Theory Concepts 11 Systems and Models 12 Control Systems 13 Feedback, Feedforward, and Adaptive Systems 14 Principle of Negative Feedback 15 Regulated Variables and Properties 16 Control Configurations 17 Summary 2 Hypotheses of Motor Servo Function 21 Salient Features of the Available Sensors 22 Follow-up Servo Hypothesis 23 Spindle Receptors as Model-Reference Error Detectors 24 Conditional Feedback and Servo Assistance 25 β-System and the Possibility for Zero Sensitivity 26 Stiffness Regulation 27 Summary Model 28 Adaptive Models 29 Summary 3 Muscle Mechanical Stiffness 31 Stiffness Definitions 32 Length Dependence 33 Recruitment of Motor Units 34 Rate Modulation of Motor Units 35 Instantaneous Stiffness and Short-Range Elasticity 36 Instantaneous Stiffness Beyond the Short-Range Region 37 Ramp Responses: Transient Properties and Nonlinearity 38 Natural Combinations of Recruitment and Rate Modulation 39 Summary 4 Central Pathways 41 Primary Ending Projections 42 Tendon Organ Projections 43 Projections From Secondary Endings and Group II Free Nerve Endings 44 Projections From Groups III and IV Free Nerve Endings 45 Clasp-Knife Reflex 46 Long-Loop Reflexes 47 Summary 5 Simplified Animal Models 51 Decerebrate Preparation 52 Spinal Preparation 53 Summary 6 Tonic Stretch Reflex in Functionally Isolated Muscles 61 Basic Features of the Stretch Reflex 62 Static Force-Length Relations 63 Normalized Stiffness 64 Mechanically and Neurally Mediated Components 65 Actions of Control Signals on the Motor Servo 66 Dependence of Incremental Stiffness on Initial Force 67 Loop Gain of Force Feedback 68 Summary 7 Static Regulatory Characteristics in Intact Subjects 71 Skeletal Mechanics and Coordinate Systems 72 Steady-State Responses to Changes in Load Force 73 Torque-Angle Relations 74 Equivalent Stiffness and the Concept of Composite Motor Servos 75 Effect of Instructional Set 76 Gain Variation vs Gain Control 77 Summary 8 Dynamic Responses to Mechanical Disturbances 81 Dynamic Features of Force Development 82 Dependence of Transient Responses on Initial Force 83 Amplitude Dependence and Linearity 84 Asymmetry of Motor Servo Response 85 Compensation for Yielding 86 Predictive Compensation: Feedforward vs Nonlinear Feedback Viewpoints 87 Vibration and the Stretch Reflex 88 Velocity Dependence and Damping 89 Summary 9 Implementation of Movement Commands 91 α-γ-Relations 92 Positional Stiffness Deduced From Spindle Relations 93 β-Innervation of Muscle Spindles 94 Analytical Approaches to Actions of α-, β-, and γ-Motoneurons 95 Equilibrium Point Control 96 Stiffness Regulation vs Stiffness Control 97 Perturbations During Movement 98 Compliance, Load Compensation, and Biological Design 99 Summary

Output Fluctuations and Gradual Price Adjustment

Abstract: This paper reviews the leading ideas that have emerged within two paradigms of price adjustment. Neither, it appears, provides a satisfactory theoretical scheme when taken in isolation. This paper concludes that an attempt to merge the more convincing elements of each is needed, and some suggestions for such a merger are put forward.

Value Theory Without Efficiency

Abstract: A semivalue is a symmetric positive linear operator on a space of games, which leaves the additive games fixed. Such an operator satisfies all of the axioms defining the Shapley value, with the possible exception of the efficiency axiom. The class of semivalues is completely characterized for the space of finite-player games, and for the space pNA of nonatomic games.

Cross-language phonetic interference: arabic to english*

Abstract: This study compares phonetic implementation of the stop voicing contrast produced in Arabic by Saudi Arabians and by both Americans and Saudis in English. The English stops produced by Saudis manifested temporal acoustic correlates of stop voicing (VOT, stop closure duration, and vowel duration) similar to those found in Arabic stops. Despite such phonetic interference from Arabic to English, however, American listeners generally had little difficulty identifying the English stops produced by the Saudis, with the exception of /p/. This phoneme, which is absent in Arabic, was frequently produced with glottal pulsing during the stop closure interval. The timing of /p/, however, suggests that the Saudis did grasp the phonological nature of /p/ (i.e., that the contrast between /p—b/ is analogous to that between /t—d/ and /k—g/) but were unable to control all the articulatory dimensions by which this sound is produced.

Using Information Processing Theory to Design Marketing Strategies

Abstract: The research demonstrates the usefulness of information processing in designing marketing strategy. Two strategies based on information processing theory are shown to be effective in combating the ...

Efficiency of the Market for Racetrack Betting

Abstract: Many racetrack bettors have systems. Since the track is a market similar in many ways to the stock market one would expect that the basic strategies would be either fundamental or technical in nature. Fundamental strategies utilize past data available from racing forms, special sources, etc. to "handicap" races. The investor then wagers on one or more horses whose probability of winning exceeds that determined by the odds by an amount sufficient to overcome the track take. Technical systems require less information and only utilize current betting data. They attempt to find inefficiencies in the "market" and bet on such "overlays" when they have positive expected value. Previous studies and our data confirm that for win bets these inefficiencies, which exist for underbet favorites and overbet longshots, are not sufficiently great to result in positive profits. This paper describes a technical system for place and show betting for which it appears to be possible to make substantial positive profits and thus to demonstrate market inefficiency in a weak form sense. Estimated theoretical probabilities of all possible finishes are compared with the actual amounts bet to determine profitable betting situations. Since the amount bet influences the odds and theory suggests that to maximize long run growth a logarithmic utility function is appropriate the resulting model is a nonlinear program. Side calculations generally reduce the number of possible bets in any one race to three or less hence the actual optimization is quite simple. The system was tested on data from Santa Anita and Exhibition Park using exact and approximate solutions that make the system operational at the track given the limited time available for placing bets and found to produce substantial positive profits. A model is developed to demonstrate that the profits are not due to chance but rather to proper identification of market inefficiencies.

Induced mood and the illusion of control.

Abstract: Alloy and Abramson reported that depressed students give relatively accurate judgments of the degree of contingency between their responses and outcomes while nondepressed students show an "illusion of control" and overestimate their impact on objectively uncontrollable outcomes that are frequent and/or desired. The present experiment examined the directionality of the relationship between realism in judging personal control and depression. Depressed and elated mood states were induced transiently in naturally nondepressed and depressed students, respectively, and the impact of these transient mood states on susceptibility to the illusion of control was assessed. Naturally nondepressed women made temporarily depressed gave accurate judgments of control while naturally depressed women made temporarily elated showed an illusion of control and overestimated their impact on an objectively uncontrollable outcome. In addition, mood induction groups showed predicted changes in self-reported affect and a behavioral measure of depression. These findings cannot be attributed to demand characteristics because nondepressed and depressed women instructed to simulate depression and elation, respectively, behaved differently than their respective mood induction groups. An intriguing implication of these findings may be that therapeutic interventions for depression that successfully remediate depressive symptoms may also increase depressed individuals' susceptibility to the illusion of control.