Feedback system design: The single-variate case — Part I

A recently developed algebraic approach to the feedback system design problem is reviewed via the derivation of the theory in the single-variate case. This allows the simple algebraic nature of the theory to be brought to the fore while simultaneously minimizing the complexities of the presentation. Rather than simply giving a single solution to the prescribed design problem we endeavor to give a complete parameterization of the set of compensators which meet specifications. Although this might at first seem to complicate our theory it, in fact, opens the way for a sequential approach to the design problem in which one parameterizes the subset of those compensators which meet the second specification...etc. Specific problems investigated include feedback system stabilization, the tracking and disturbance rejection problem, robust design, transfer function design, pole placement, simultaneous stabilization, and stable stabilization.This research was supported by the Joint Services Electronics Program at Texas Tech University under ONR Contract 76-C-1136.     

The Architecture of an Electronic Book

The architecture of a very large scale integration (VLSI) based system capable of storing, processing, and displaying information normally contained in book form is presented in this paper. The operational characteristics of the system, including complex string search capabilities, are discussed. Portability aspects of the system are considered. The implications of VLSI-based electronic books in industry and in the scientific, legal, and medical professions are outlined. Educational possibilities for such systems are investigated. Technology requirements are defined.     

Lexical semantic and associative priming in Alzheimer's disease.

Semantic memory impairment was investigated in patients with probable Alzheimer's disease (AD) using a threshold oral word reading task to assess priming of different lexical relationships. Healthy elderly controls showed significant priming for associatively related nouns (tempest-teapot) and also for nouns semantically related either because both designate basic-level exemplars of a common superordinate category (cousin-nephew) or because the target names the superordinate category of the prime (daughter-relative). AD patients, in contrast, showed preserved priming of lexical associates but impaired priming of certain semantic relationships. They showed no priming between words designating coordinate exemplars within a category, despite preserved priming of the superordinate category label. Findings are consistent with the view that at least part of the semantic deficit in AD is due to disruption of semantic knowledge that affects relationships among basic-level concepts, more than the relationships between these concepts and their corresponding superordinate category of membership. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An experimental study in electrical impedance tomography usingbackprojection reconstruction

This paper reports on experiments designed to evaluate the performance of the equipotentials backprojection method under conditions modeling those of proposed applications of electrical impedance tomography. Small spherical targets were placed inside a saline-filled tank with dimensions similar to a human torso. Data were acquired with a computer-based instrument that applies current to pairs of electrodes located on two horizontal planes and records potential differences between electrodes of a third plane. The relative contrast produced by nonconducting spheres in a uniform saline background was measured on the reconstructed images and used to determine system sensitivity to target volume and to the radial and vertical positions of single spheres. Results show that for radial positions within a critical radius sensitivity is always maximum when the spheres center is on the recording plane and decreases gradually when the target is moved outside this plane. Localization of simple targets in 3-D, with data acquired from multiple recording planes, appears feasible. The results provide guidelines for the interpretation of images with complex 3-D conductivity distributions.     

Longitudinal analysis of the relationship between changes in smoking and changes in drinking in a community sample: The Winnipeg Health and Drinking Survey.

Smoking cigarettes and drinking alcohol are positively correlated in cross-sectional studies of the general population. However, it is unclear whether changes in quantity of drinking over time are related to changes in amount of smoking over time. This investigation examined, with structural equation modeling, the relationship of changes in drinking to changes in smoking over 2 years among 344 adults who reported cigarette smoking and alcohol use at baseline in 1989-1990 or at follow-up in 1991-1992 or both. Surprisingly, no significant relationships were found between changes in smoking and changes in drinking. This lack of effect suggests that changes in the quantity or intensity of drinking and of smoking are not related in any important way in nonclinical populations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Testing aqueous caustic electrolyzers at high temperatures

Increasing the electrochemical cell operating temperature allows a general improvement of the operating energetics of hydrogen production via alkaline solution water electrolysis. Considerations of operation of these advanced cells above 100°C leads to a reexamination of all of the basic materials stabilities. One previous controversy has been with respect to the upper temperature value for a stable asbestos electrochemical cell separator. In addition to testing alternative materials for the cell separator, one must examine which of the structural polymers can be used as a cell frame, reexamine the stability of the selected anode electrocatalyst and finally, determine if the plumbing and piping selected will introduce corrosion products which could affect the cathode electrocatalyst. This paper describes the work performed at Teledyne Energy Systems on the studies of alkaline electrolyzers and materials for operation at temperatures up to 150°C. This program, under contract to the Brookhaven National Laboratory, has proceeded through the design and construction of an applied research sized test system. The materials testing and preliminary test results obtained with the system are described.     

A Machine for Adiabatic Toroidal Compression

The Adiabatic Toroidal Compressor (ATC) is being built to investigate the feasibility of a proposed technique for increasing the density and ion temperature of conventional tokamaks. By applying a suitable magnetic field normal to the plane of a usual tokamak discharge, the major radius is caused to shrink to about 0.4 of its original value, thereby resulting in an increase both in temperature and density. The experiment is important because, if successful, the technique could be applied to achieve plasma temperatures and densities significantly greater than otherwise obtainable in a given size facility. Selection of the machine size, field strength and time scale for the operating cycle was based both on the desire to achieve values of temperature and density well exceeding those already reported by others and on the conviction that experimental results should be forthcoming by mid-1972 to be useful in the design of larger experimental facilities. The first goal is expected to be met in the choice of a field strength of 50 kG at 37 cm major radius, the location of the 241 kA discharge after compression. The second goal required the use of presently available (or readily constructed) power supplies and an amount of engineering manpower consistent with existing laboratory programs. Buildup of the initial discharge within about 5 ms, a thermalizing time of up to 20 ms, and a compression time of about 2 ms are attainable within the above framework and are consistent with the energy replacement time of the plasma.     

Influence of functional impairment and social support on depressive symptoms in persons with diabetes.

Tested the hypothesis that, among patients with higher levels of illness-related impairment, adequate social support would act as a buffer against depression. 158 Ss (aged 17–78 yrs) with insulin-dependent diabetes mellitus completed the Beck Depression Inventory, a health status measure, and 2 measures of social support. Depressive symptoms correlated positively with functional impairment and negatively with adequacy of social support. In addition, social support moderated depression in the face of greater impairment such that, among Ss who reported the most illness-related functional disabilities, adequate support provided a relative protection from depression. Individuals with inadequate support seem to be most at risk for depression when disability related to illness increases. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of gender role incongruities on men's experience as clients in psychotherapy.

Discusses male gender roles, conflicts, and dynamics in psychotherapy. Case illustrations of 3 men in psychotherapy are given. The cases stress that men must always be viewed in the context of the restraints and expectations of the male gender role. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chemistry of the mandibular gland secretion of the Indian beePithitis smaragdula

The mandibular glands of the stem-nesting Indian beePithitis smaragdula contain a mixture of salicylaldehyde, citronellyl acetate, geranyl acetate, pentadecane, heptadecane, ethyl tetradecanoate, and ethyl hexadecanoate. Salicylaldehyde is reported for the first time from a hymenopterous source. The secretion, emitted when the bee is disturbed, is rubbed with the legs over the bee's body and the disturbing object. The reactivity of some of the components in combination with the bee's behavior make the glandular exudate an effective defensive secretion.