Dynamic computational geometry on meshes and hypercubes

Parallel algorithms are given for determining geometric properties of systems of moving point-objects. The objects are assumed to be moving in a Euclidean space such that each coordinate of a point's motion is a polynomial of bounded degree in the time variable. The properties investigated include nearest (farthest) neighbor, closest (farthest) pair, collision, convex hull, diameter, and containment. Several of these properties are investigated from both the dynamic and steady-state points of view. Efficient, and often optimal, implementations of these algorithms are given for the mesh and hypercube.Research partially supported by a grant from the Niagara University Research Council.Research partially supported by National Science Foundation grants DCR-8608640 and IRI-8800514.     

A model for training psychologists to provide services for children and adolescents.

Background and rationale for a comprehensive model of training for psychologists to provide services to children and adolescents are outlined. Eleven integrated aspects of training are described with respect to training topics, justification for the training, and ways to implement the training. The model described address the need for guidance in training specialists in psychologically based mental health services for children, adolescents, and their families. Practitioners can use this model to assess their own backgrounds, knowledge, and skills in working with these populations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measurement and interpretation of zeolite NaA builder performance

Ion exchange isotherms are commonly used to describe the distribution of ions between a solid and liquid phase under equilibrium conditions. In the detergent industry, the Ca-Na-zeolite A isotherm can be utilized to determine the builder performance of zeolite NaA under a specific set of experimental conditions. In this paper, we demonstrate how the Ca-Na-zeolite A isotherm is developed and utilized in measuring and interpreting the calcium exchange capacity score of zeolite NaA. Owing to the large number of testing parameters that affect the equilibrium distribution of calcium between the zeolite and solution phases, and hence the calcium exchange capacity score of the zeolite, a recommendation is made as to a standard set of test conditions that provide for both analytical precision and convenience. With this approach, builder performance differences between any two zeolites can then easily be measured and assessed. As an extension to the isotherm principles developed in this paper, the prediction of zeolite performance in real detergent systems is illustrated. Particular attention is given to the more efficient utilization of the ion exchange capacity of zeolite NaA by the recently developed concentrated detergent systems. A portion of this paper was presented at the 1992 Annual AOCS Meeting in Toronto, Canada.     

The Bit (and Three Other Abstractions) Define the Borderline Between Hardware and Software

Minds and Machines - Modern computing is generally taken to consist primarily of symbol manipulation. But symbols are abstract, and computers are physical. How can a physical device manipulate...     

Towards bridging the neuro-symbolic gap: deep deductive reasoners

Applied Intelligence - Symbolic knowledge representation and reasoning and deep learning are fundamentally different approaches to artificial intelligence with complementary capabilities. The...     

An Application of Two-Phase DC Chopper Motor Drive

During the past ten years the Army has invested a sizable effort into new systems configurations and development programs to improve ground vehicle mobility. United States Army Mobility Equipment Research and Development Center (USAMERDC), Fort Belvoir, Va., has been particularly interested in an improved vehicle mobility for off-highway vehicles, amphibians, and engineer equipment through electrical propulsion. Such drive systems incorporating individual wheel controls provide improved mobility over all types of terrain, simplified supply logistics, and permit a more functional vehicle design and construction. Past experience in industry and in the government has shown that the dc motor propulsion drive is inherently simple to install and to maintain. The dc motor is somewhat heavier than comparable ac motors due to motor speed limitations; however, the dc machine, particularly the series field motor, requires relatively simple power controls since the power is processed by the motor's own commutator. Commercial dc traction motors have an inherent high-torque starting characteristic which is mandatory for engineer-type vehicle propulsion applications. In the midspeed range however, presently available dc motor propulsion drives under consideration for the Anny have unsatisfactory acceleration performance when compared to conventional mechanical drive systems comprised of a spark or compression ignition engine and a multispeed transmission. In this context, the paper discusses this Center's experimental solid-state controller and the method employed to improve the acceleration or peak power propulsion profile of an electric vehicle drive using dc series field motors.     

Design Analysis of Multiphase DC Chopper Motor Drive

DC chopper propulsion speed control is attained by a solid-state switch whose variable on-off duty cycle transfers a proportional quantity of pulsed energy into a motor. The pulsed battery current is alternately stored and expended within the dc motor and its series connected dc choke during each period of conduction and succeeding freewheeling operating mode. Hence an energy transfer is maintained transforming a high voltage low dc supply into a lower voltage higher dc demanding load. The transformation ratio is considered a controlled variable by simply controlling the on-off conduction duty cycle of its solid-state switch. This simplistic approach, however, fails to recognize that the instantaneous battery current amplitude equals the motor current demand during the switch ``on' period resulting in potentially very large peak power demands [1].     

Inhibition in superior colliculus neurons in a brightness discrimination task?

Simultaneous recordings were collected from between two and four buildup neurons from the left and right superior colliculi in rhesus monkeys in a simple two-choice brightness discrimination task. The monkeys were required to move their eyes to one of two response targets to indicate their decision. Neurons were identified whose receptive fields were centered on the response targets. The functional role of inhibition was examined by conditionalizing firing rate on a high versus low rate in target neurons 90 ms to 30 ms before the saccade and examining the firing rate in both contralateral and ipsilateral neurons. Two models with racing diffusion processes were fit to the behavioral data, and the same analysis was performed on simulated paths in the diffusion processes that have been found to represent firing rate. The results produce converging evidence for the lack of a functional role for inhibition between neural populations corresponding to the two decisions.