Guaranteed cost inequalities for robust stability and performance analysis

In this paper, we formulate robust stability and performance bounds in terms of guaranteed cost inequalities. We derive new guaranteed cost bounds for plants with real structured uncertainty, and we reformulate them as linear matrix inequalities (LMIs). In particular, we obtain a shifted linear bound and a shifted inverse bound, and give LMI forms for a shifted bounded real bound, a shifted Popov bound, a shifted linear bound and a shifted inverse bound. Several examples are used to compare the shifted bounds with their unshifted counterparts and to make comparisons among these new bounds and vertex LMI bounds. Copyright © 2002 John Wiley & Sons, Ltd.     

Effects of DC testing on AC breakdown strength of XLPE insulatedcables subjected to laboratory accelerated aging

The results of a study performed on crosslinked polyethylene (XLPE) insulated cables tested in the laboratory under accelerated conditions are described. URD-type cables rated at 15 kV were aged at 60 Hz, 6 kV/mm, (150 V/mil) and load cycled daily to 90°C conductor, with water inside the pipe and outside of the samples, for periods of up to 3 years. DC testing was performed before and during the aging. An anticipated significant reduction in the AC breakdown strength is observed in control cables (not DC tested), from 44 kV/mm (1100 V/mil) for unaged cables, to 10 kV/mm (250 V/mil), for aged cables. However, there was no further reduction in the AC breakdown strength of cables subjected to DC testing as compared to those that are not tested with DC. It is concluded that AC breakdown strength is not an effective diagnostic tool for determining the effect of DC testing of URD cables aged under the conditions described     

Multiplication by integer constants

Methods are given for finding a sequence of ‘add’, ‘subtract’ and ‘shift’ instructions to multiply the contents of a register by an integer constant. Each method generalizes the previous one and requires only a few intermediate or scratch registers. A variation of the last method is used in the PL.8 compiler and uses an unnoticeable amount of the overall compile time. Some statistics roughly indicating the effectiveness of the methods are presented.     

Selective interference in rhesus monkey (Macaca mulatta) intragroup agonistic episodes by age–sex class.

A group of rhesus monkeys, consisting of 8 matrilines of up to 4 generations each and 9 unrelated adult males, was studied for 2 yrs. Group size varied between 75 and 91 individuals. Data collection consisted of ad lib recording of agonistic interactions. Results indicate that adult male interference in agonistic episodes was strongly biased against adolescent and adult male participants, whereas adult female interference was biased in favor of kin and in support of younger animals against older animals. Although natal males also were biased in favor of their kin, their selective targeting of sexually mature males was independent of kinship. Adolescent males targeted adult males, but only in defense of kin. It is suggested that this selective interference against adolescent and adult males by adult males has the potential to profoundly modify male agonistic participation in intragroup encounters after puberty. Because female support is influenced primarily by kinship, females less consistently interfere against male agonistic participants. Adult males may therefore play an important role in the socialization of male agonistic expression. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of encoding task on age-related differences in the functional neuroanatomy of face memory.

Age-related differences in brain activity mediating face recognition were examined using positron emission tomography. Participants encoded faces using a pleasant-unpleasant judgement, a right-left orientation task, and intentional learning. Scans also were obtained during recognition. Both young and old groups showed significant effects of encoding task on recognition accuracy, but older adults showed reduced accuracy overall. Increased brain activity in older adults was similar to that seen in young adults during conditions associated with deeper processing, but was reduced during the shallow encoding and recognition conditions. Differential correlations of brain activity and behavior were found that suggest older adults use unique neural systems to facilitate face memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chattering linear systems: A model of rapidly oscillating coefficients

We introduce linear control systems, termed chattering systems, which model instantaneous oscillations in the control parameters. Such systems serve as a limit case of systems with rapidly oscillating control parameters, which can be analyzed as perturbations from the chattering model. Several optimization and regulation problems for chattering systems are examined, along with the robustness property: the possibility of employing the solutions of the chattering case in the rapidly oscillating approximations. The theory is demonstrated on an example of an armature-controlled dc motor.     

Comparative psychology: The next 100 volumes.

Comparative psychologists study the "mind" of animals by studying what animals do and what animals are capable of doing. Different investigators address questions of proximal cause, motivation, physiological mechanism, evolutionary and ontogenetic considerations, as well as functional consequences. Some use animal subjects to explore universal theories of behavior; others focus on the diversity of behavior itself. A number of theoretical positions guide the different approaches. Some theories have been proven woefully inadequate, even fatally flawed, but no discipline thrives solely on the validity of a single theory. Let us preserve the data and discard discredited hypotheses, but let us continue to advance our discipline and refrain from wallowing in remorse over erroneous earlier ideas. Ideas are exciting but data endure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stress processes and the misuse of drugs in older adults.

There is increasing concern about the misuse of drugs among the elderly. We assessed misuse, including drug usage, drug interactions across pharmacologic classes, and multiple drugs in the same pharmacologic class, in a community sample of sixty-five 74-year-olds, and evaluated its relation to stress and coping processes and psychological and somatic health. Assessments were made repeatedly over a 6-month period. Results indicated that misuse was multidimensional and widespread. Misusers did not differ from nonmisusers on antecedent psychosocial variables, nor did they report more hassles or cope differently than nonmisusers. However, misusers and nonmisusers differed on their subjective experience of stressful encounters; misusers experienced their hassles as more intense, and they experienced more threat emotions and more dissatisfaction with their coping than did nonmisusers. Misuse was also associated with long-term psychological satisfaction, psychological symptoms, and somatic health. (PsycINFO Database Record (c) 2010 APA, all rights reserved)