High-Temperature/Field Alternating-Current Behavior of ZnO-Based Varistors

The ac electrical response of the grain boundary in the ZnO–Bi₂O₃-based varistor system (in the frequency range 10⁻²≤f≤10⁷ Hz) has been analyzed using complex plane analysis techniques as a function of temperature (90°≤T≤150°C) and electric field (E_60%lmA/cm2≤E≤E_lmA/cm2). The high-temperature/field data were best represented in the impedance plane. The lumped parameter equivalent circuit representation, containing a voltage variable resistive element associated with the grain boundary, was in agreement with a model previously reported in the literature. The resulting equivalent circuit representation of the grain-boundary response consisting of a resistance and a capacitance are interpreted in terms of various phenomena occurring at the electrical thickness of the grain boundary.     

Interactive Graphical Minimax Location of Multiple Facilities with General Constraints

An optimal algorithm for solving constrained minimax location problems has been previously reported, with the major limitation that only a single new service facility is allowed. Algorithmic extensions have now been developed and implemented on an advanced color-graphics system for the location of any number of new facilities to collectively serve the set of existing facilities. The minimax criterion is again considered for the optimization, and nonconvex constraint sets are permitted.     

Improved Wavenumber Resolution for Small Arrays

The objective of the method described is to compute the Fourier transform of a function of space and time with a significant improvement in the resolution of spatial frequencies, particularly in the case of small arrays for which the size of the array is on the order of one wavelength (or less). This improvement is initially developed by considering the conversion of spatial frequency into temporal frequency through the oscillatory motion of a single receiver. A more practical scheme is next presented in which the oscillatory motion is created synthetically by the appropriate sequential sampling of individual elements in a receiving array. Both forms of this method (realand synthetic motion) besides providing some degree of ?super-resolution? are linear and indicative of amplitude as well as phase.     

Hierarchical control model for automated manufacturing systems

A mathematical model is presented to determine the hierarchical computer control requirements for a completely automated flexible manufacturing systems. This model can estimate the number and capacity of hierarchical computers needed to control a specified automated manufacturing system. The hierarchical control system is described by the major operating components common to all controlling computers and computer numerical controlled (CNC) machines: central processing unit, memory, input/output and communications. Each of these components is evaluated with respect to its operating speed and capacity. Costs are then determined as a function of the component's processing speed and capacity.A three-tier control system is examined. Starting with the CNC machines' speeds and capacities, each level of the computer hierarchical control system is modeled and related to the next tier by communication and data requirements. The physical machine layout required for a hierarchical control system is discussed. Part scheduling and process information requirements are also addressed. The model's utility is illustrated by an example using a typical manufacturing system.Optimization of this model is readily obtained using standard dynamic programming techniques. Being totally independent of any specific computer hardware technology, the model can be applied to present and future automated manufacturing systems.     

Behavioral ecology of time allocation in California ground squirrels (Spermophilus beecheyi): Microhabitat effects.

The behavior of 34 California ground squirrels was measured in the field, and all behavioral samples occurring within the same 5?×?5 m quadrat of the 100?×?100 m study area were pooled. The number and proximity of burrows, rocks, and trees around the center of each quadrat were measured, and these microhabitat attributes were used as predictor variables in multiple regression analyses in an attempt to account for interquadrat variance in time allocated to common behaviors. For the 3 most common behaviors (forage, vigilance, and locomotion), 56–75% of the variance among quadrats was accounted for by the microhabitat variables. Each behavior was accounted for by a unique combination or ordering of the predictor variables. Testable hypotheses are offered as to the adaptive significance of the observed behavior–habitat correlations. Results support the contention that the utility of a behavior varies spatially according to the probability of encountering biologically important factors and that these probabilities are partly predictable by small-scale characteristics of the habitat. (68 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Industrial psychology: In need of a learned lawyer?

Outlines the search for theoretical and conceptual structure and the pressures toward codification of standards and values in the professions of law and industrial psychology. Whereas the law profession resolved its "growth pains" by falling back on its corpus of precedents, rules of procedure, and hierarchic structure, industrial psychology, which to a great extent was born from the business community, has never been allotted the time to develop. As a result, industrial psychology has become a profession, but to this day, lags behind as a science. The need for industrial psychology to rethink its position vis-à-vis the business community and to become an autonomous scientific discipline is discussed. Suggestions are offered to aid industrial psychology in reexamining its assumptions, symbols, premises, and rationales to enable its scientifically based professionalism to eventually become confirmed among its sister disciplines. (4 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Methane-based equations of state for a corresponding states reference substance

Two equations of state have been developed, one valid over the reduced temperature range 0.2–26 and the other over 0.35–26. Both are intended for use as reference equations of state in the calculation of thermodynamic properties via the principle of corresponding states. The equations are essentially equations of state for methane in that they reproduce the experimentally measured properties of the fluid phase over the whole region for which they exist (reduced temperatures of 0.47 to 3.3) but the extension to higher temperatures was made by utilizing experimental measurements made on nitrogen and hydrogen. An empirical scheme was used for temperatures below 0.47.     

Expectancy factors in the treatment of fear: Methodological and theoretical issues.

Critically reviews the literature assessing the importance of Ss' expectation of therapeutic gain in facilitating fear reduction. Reviewed studies fall into 2 major categories: those that compare the relative efficacy of systematic desensitization and placebos and those that attempt to manipulate Ss' expectation of therapeutic gain within a particular technique (e.g., systematic desensitization). The methodological problems with this research include the failure of investigators to evaluate the experiential impact of expectancy-inducing instructions, the use of unconvincing placebo manipulations, and the predominant employment of mildly fearful, poorly motivated Ss. In spite of these problems, it is tentatively concluded that expectancy manipulations are important change mediators. Several mechanisms may explain how expectancy mediates change, including increased compliance with real treatment procedures; increased tendency to test reality after having undergone an "effective" therapy, with subsequent fear extinction and self-reinforcement for behavioral improvement; modification of demand characteristics after treatment; and modification of cognitive events controlling fear responding. (71 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Performance Bounds for Convolutional Codes with Digital Viterbi Decoders in Gaussian Noise

With digital implementations of the Viterbi decoding algorithm for convolutional codes, soft quantization is preferred over hard quantization because it generally yields superior performance. Since the decoder needs to know the signal energy and channel noise variance with soft quantization, inaccurate information can result in a mismatch between the channel and decoder. Bounds which are tight for high signal-to-noise ratios are obtained on the bit error probability using the generating function approach. Automatic gain control level inaccuracies, imperfect carrier phase, symbol timing synchronization error, and path metric digitization are discussed in the context of a mismatch between the channel and decoder.     

Long-term effects of control and predictability-enhancing interventions: Findings and ethical issues.

Examined the long-term effects of participating in a field experiment on the effects of control and predictability-enhancing interventions. 40 retirement home residents who had initially benefited from being exposed to a specific positive predictable or controllable event (visits by college students) were assessed at 3 different intervals after the study was terminated. Health and psychological status data collected 24, 30, and 42 mo after the study indicated no positive long-term effects attributable to the interventions. In fact, groups that had initially benefited from the interventions exhibited precipitous declines once the study was terminated, whereas groups that had not benefited remained stable over time. Theoretical and ethical implications are discussed. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)