Pareto-based negotiation in distributed multidisciplinary design

The process of distributed engineering design calls for a methodology making use of the most recent advances in optimization-based design including multidisciplinary and multiobjective optimization. In distributed design, the participating teams do not have access to the design problems of other teams but may exchange limited information about their own current designs, making negotiation among themselves a key mechanism to reach a desired compromise which, nevertheless, is also a Pareto design to the original problem. A mathematical model of this distributed but decomposable design process is posed and solved using Lagrangian relaxation, while Pareto optimality is equivalently converted to single-objective optimality by means of multicriteria decision making strategies. The proposed coordination algorithm allows negotiation among the teams (subproblems) by sharing only limited information that is restricted to values of optimization quantities. The proposed modeling and solution scheme is applied to a numerical example representing the design of vehicle subsystems and components.     

Psychological resources, positive illusions, and health.

Psychological beliefs such as optimism, personal control, and a sense of meaning are known to be protective of mental health. Are they protective of physical health as well? The authors present a program of research that has tested the implications of cognitive adaptation theory and research on positive illusions for the relation of positive beliefs to disease progression among men infected with HIV. The investigations have revealed that even unrealistically optimistic beliefs about the future may be health protective. The ability to find meaning in the experience is also associated with a less rapid course of illness. Taken together, the research suggests that psychological beliefs such as meaning, control, and optimism act as resources, which may not only preserve mental health in the context of traumatic or life-threatening events but be protective of physical health as well. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive neuroscience: A field with increasing interest to school psychologists.

Reviews the book, Cognitive neuroscience: The biology of the mind by M. Gazzaniga, R. B. Ivry, and G. R. Mangun (1998). This excellent book on cognitive neuroscience provides an exposition of the key areas concerned in cognitive neuroscience for the advanced student in adult neuropsychology and/or biological psychiatry. The authors' aim to balance theory with neuropsychology utilizing neuroscientific evidence to support a theoretical basis is a major contribution of this text. In this book there has been a concerted effort to provide a theoretical basis for cognitive neuroscience in addition to a list of empirical evidence. Such an effort provides a backdrop for future research as well as linking various cognitive functions into an understandable whole. This volume provides an excellent overview of brain anatomy and function. The book is highly readable and provides excellent illustrations of complex material. The main weakness of this volume for school psychologists is the emphasis on adult disorders with no real discussion of the most common childhood disorders. Although the text assumes some familiarity with neuroanatomy, it is useful for practitioners who desire more up-to-date information in this exciting field. This volume would be an excellent textbook for courses in biological bases of behavior for doctoral-level school psychologists, provided there is accompanying information on child neuropsychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decreasing GAD neonatally attenuates steroid-induced sexual differentiation of the rat brain.

During development, exposure to gonadal steroids results in brain sexual differentiation. Postnatally, hypothalamic gamma-aminobutyric acid (GABA) levels are almost double in males versus females. We hypothesized that increased GABA neonatally results in masculinization. Males, females, and androgenized females were infused intrahypothalamically with antisense oligonucleotides against glutamic acid decarboxylase (GAD) mRNA at birth to reduce GABA synthesis. GAD protein and GABA levels were reduced 24 hr later without obvious toxic effects, as determined by histological examination. As adults, neonatally antisense-treated, androgenized females showed reduced intromission-like behavior and lordosis quotients compared with vehicle and scrambled controls. Lordosis quotients were reduced about 50% in nonandrogenized females versus vehicle and scrambled controls. These data suggest that GABA is involved in mediating brain sex differentiation and may act in both males and females. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using Absolute Metric Maps to Close Cycles in a Topological Map

In simultaneous localisation and mapping (SLAM) the correspondence problem, specifically detecting cycles, is one of the most difficult challenges for an autonomous mobile robot. In this paper we show how significant cycles in a topological map can be identified with a companion absolute global metric map. A tight coupling of the basic unit of representation in the two maps is the key to the method. Each local space visited is represented, with its own frame of reference, as a node in the topological map. In the global absolute metric map these local space representations from the topological map are described within a single global frame of reference. The method exploits the overlap which occurs when duplicate representations are computed from different vantage points for the same local space. The representations need not be exactly aligned and can thus tolerate a limited amount of accumulated error. We show how false positive overlaps which are the result of a misaligned map, can be discounted.     

Development of a virtual reality laboratory stressor

Virtual Reality - This research report describes the development of a virtual reality (VR) laboratory stressor to study the effects of exposure to stressful events. The aim of the research was to...     

As easy as pie

3-D or perspective pie charts are popular graphical displays, especially now that they are so easy to produce on computers, but they are problematical because they distort the very features that communicate the information about the data. This paper presents evidence to support the hypothesis that such distortions can lead to mis-information being obtained from such graphs. In particular the orientation of the segments is crucial to the interpretation of the data. This evidence comes from an experiment on a large number of subjects from varied backgrounds and ages who were asked to identify the largest and smallest segments in a 3-D pie chart. For some graphs the numbers of respondents who identified the segments incorrectly far exceeded those who identified them correctly. A control group who carried out the same task for 2-D pie charts were all able to correctly identify the largest and smallest segments in each graph.     

Evaluating worker vibration exposures using self-reported and direct observation estimates of exposure duration

The objective of this study was to compare objective and subjective methods of collecting exposure time data for hand arm vibration (HAV) and whole-body vibration (WBV), and to evaluate the impact of inaccurate exposure times’ on the calculation of the average vibration exposure over an 8 h working day A(8).The study was carried out in the engineering services and maintenance departments of a construction and property management company. Worker exposure time data was collected using three methods, questionnaire surveys, daily worker interviews and 8 h direct workplace observations. Vibration magnitudes (m/s²) were measured for a range of hand tools and vehicles, and daily vibration exposure estimates A(8) were calculated using exposure times observed, reported in interview and self reported in the questionnaire.Results from the study showed that self-reported exposure time estimates from the questionnaire survey were a factor of 9.0 (median value) times greater for HAV and a factor of 6.0 (median value) times greater for WBV when compared with direct observation estimates. Exposure times reported in interview were higher, than those observed, but more reliable than those self reported in the questionnaire; a factor of 2.1 (median value) times greater for HAV and a factor of 1.4 (median value) times greater for WBV. A(8) values calculated using questionnaire exposure times were up to 66% and 75% greater for sources of HAV and WBV respectively when compared to A(8) values calculated using observed exposure times.For the purposes of carrying out a reliable risk assessment, results from this study indicate that direct measurements of worker exposure time are not recommended over questionnaires especially where work is highly variable for example in construction and property management. Worker interviews or direct workplace observation methods were found to be reliable alternative methods for collecting exposure time.     

Further explorations of perceptual speed abilities in the context of assessment methods, cognitive abilities, and individual differences during skill acquisition.

Measures of perceptual speed ability have been shown to be an important part of assessment batteries for predicting performance on tasks and jobs that require a high level of speed and accuracy. However, traditional measures of perceptual speed ability sometimes have limited cost-effectiveness because of the requirements for administration and scoring of paper-and-pencil tests. There have also been concerns about the validity of previous computer approaches to administering perceptual speed tests (e.g., see Mead & Drasgow, 1993). The authors developed two sets of computerized perceptual speed tests, with touch-sensitive monitors, that were designed to parallel several paper-and-pencil tests. The reliability and validity of the tests were explored across three empirical studies (N = 167, 160, and 117, respectively). The final study included two criterion tasks with 4.67 and 10 hours of time-on-task practice, respectively. Results indicated that these new measures provide both high levels of reliability and substantial validity for performance on the two skill-learning tasks. Implications for research and application for computerized perceptual speed tests are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)