A study of mechanisms for improving robotic group performance

Many collaborative multi-robot application domains have limited areas of operation that cause spatial conflicts between robotic teammates. These spatial conflicts can cause the team's productivity to drop with the addition of robots. This phenomenon is impacted by the coordination methods used by the team-members, as different coordination methods yield radically different productivity results. However, selecting the best coordination method to be used by teammates is a formidable task. This paper presents techniques for creating adaptive coordination methods to address this challenge. We first present a combined coordination cost measure, CCC, to quantify the cost of group interactions. Our measure is useful for facilitating comparison between coordination methods, even when multiple cost factors are considered. We consistently find that as CCC values grow, group productivity falls. Using the CCC, we create adaptive coordination techniques that are able to dynamically adjust the efforts spent on coordination to match the number of perceived coordination conflicts in a group. We present two adaptation heuristics that are completely distributed and require no communication between robots. Using these heuristics, robots independently estimate their combined coordination cost (CCC), adjust their coordination methods to minimize it, and increase group productivity. We use simulated robots to perform thousands of experiment trials to demonstrate the efficacy of our approach. We show that using adaptive coordination methods create a statistically significant improvement in productivity over static methods, regardless of the group size.     

A self-processing network model for relational databases

In this paper, a model which combines relational databases with self-processing networks is proposed in order to improve the performance of very large databases. The proposed model uses an approach which is radically different from all other distributed database models, where each computer processes a portion of the database. In the self-processing network model, the network structure which consists of nodes and connections, captures the data and the relationships by assigning them unique, connected control, and data nodes. The network activity is the mechanism that performs the relational algebra operations. No data transmission is needed, and since data nodes are common to all the relations, integrity and elimination of data redundancy are achieved. An extension of the model, by interconnecting the data nodes via weighted links, provides us with properties that are embedded in neural networks, such as fuzziness and learning.     

Biographical data in employment selection: Can validities be made generalizable?

The hypothesis was examined that organizational specificity of biodata validity results from the methods typically used to select and key items. In this study, items were initially screened for job relevance, keying was based on large samples from multiple organizations, and items were retained only if they showed validity across organizations. Cross-validation was performed on approximately 11,000 first-line supervisors in 79 organizations. The resulting validities were meta-analyzed across organizations, age levels, sex, and levels of education, supervisory experience, and company tenure. In all cases, validities were generalizable. Validities were also stable across time and did not appear to stem from measurement of knowledge, skills, or abilities acquired through job experience. Finally, these results provide additional evidence against the hypothesis of situational specificity of validities, the first large-sample evidence in a noncognitive domain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Entwicklung eines Analysenverfahrens zur Bestimmung von metallischem und chemisch gebundenem Calcium in Stahl

Durch Kombination eines Plasmaspektrometers (ICP) mit einer neuen Apparatur zur elektrothermischen Verdampfung konnte der Gehalt an metallischem Calcium in niedrig legiertem, calciumbehandeltem Stahl bestimmt werden. Die kontrollierte Erwärmung von Stahlspänen auf 2 000°C führt zur vollständigen Verdampfung des elementaren Calciums, während das chemisch gebundene Calcium bei dieser Temperatur nicht verdampft. Das verdampfte Calcium wurde mit Argon in das Plasmaspektrometer transportiert, und das erzeugte Emissionsspektrum wurde zur quantitativen Auswertung genutzt.     

The nuclear freeze resolution: A question of empowerment.

The American Psychological Association has done little to empower the nuclear freeze resolution (NFR) adopted in 1982. The general debate on the issues of advocacy, competency, and ethics should be suspended so that the issues associated specifically with the NFR can be resolved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)