Inspecting the emperor's clothes: Evidence that random selection of leaders can enhance group performance.

This article tests the hypothesis that group performance might be superior when leaders are randomly rather than systematically selected. In Experiment 1 groups with randomly selected leaders performed a survival task better than groups whose leaders were systematically selected. This effect was replicated in Experiment 2: Groups with a random leader also performed better than groups with no appointed leader and followers adhered more strongly to the group decision. In Experiment 3, naive participants' experimental expectations confirmed the counterintuitive nature of these findings. Results suggest that systematically selected leaders can undermine group goals and group maintenance. The possibility that this occurs because leaders assert their personal superiority at the expense of shared social identity is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bayesian outlier rejection and state estimation

An outlier is a data point that contains no information about the system to be estimated. A procedure is developed, using a Bayesian cost criterion, to detect and eliminate outliers from a data base and at the same time provide estimates of the state of a dynamical system. The approach is applied to a Gauss-Markov discrete-time system and to a parameter estimation problem. For the latter case, exact solutions of estimator bias and convariance are obtained and conditions for filter divergence are discussed. The approach in this paper differs from others in that a maximum a posteriori estimate is obtained over long block lengths of data so that clustering schemes can be employed.     

Internet identifiability and beyond: A model of the effects of identifiability on communicative behavior.

K. Douglas and C. McGarty (2001) demonstrated that being identifiable to an in-group audience in a computer-mediated communication (CMC) setting leads people to describe anonymous out-group targets in more abstract or stereotypical ways. On the basis of these findings and the social identity model of deindividuation effects (SIDE; S. Reicher, R. Spears, & T. Postmes, 1995), the authors aimed to test a model of the effects of identifiability on communicative behavior in and beyond CMC. Participants in 3 studies, 1 CMC and 2 pen and paper, were asked to write responses to controversial messages. In all 3 studies, communicators who were identifiable to an in-group audience used more stereotypical language to describe anonymous out-group targets. Studies 2 and 3 suggested that rather than being strategic, this may result from more subtle or implicit communicative processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dynamics of differentiation: Similarity as the precursor and product of stereotype formation.

The degree of data-based and expected coherence within groups was predicted to enhance intergroup differentiation in the illusory correlation paradigm. Results of Study 1 indicated that data-based coherence was a prerequisite for illusory correlation, and this effect was further enhanced by expected coherence. Reinterpretations of the behaviors also augmented illusory correlation, especially when instructions provided greater scope for this, but only under conditions of data-based coherence. The finding that group coherence enhances illusory correlation contradicts recent findings of A. R. McConnell, S. J. Sherman, and D. L. Hamilton ( 1997). This anomaly was resolved by showing that the relation between group coherence and illusory correlation is curvilinear (Study 2). Illusory correlation increased with coherence but diminished when group coherence was sufficiently high to undermine meaningful evaluative differentiation between groups. Results showed that intragroup similarity is both a precursor and a product of differentiation and illusory correlation. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Reliable Satellite Communications for a Specular Multipath Channel

In many mobile satellite communication systems specular multipath exists and acts as a distortion to the transmitted message stream. In most cases there is a singular specular return which can be characterized by a delay and reflection coefficient. If this return is viewed as intersymbol interference on the channel, then it is possible to consider the resulting channel as modeled by a finite state machine and process the received data stream optimally using the Viterbi algorithm. This paper develops such a scheme and derives a performance bound. A suboptimum scheme is also developed which is less sensitive to inaccurate knowledge of the multipath parameters. Performance bounds for the suboptimum scheme are also developed.     

Cable-Based Metro Area Networks

This paper examines the system design considerations of metropolitan area networks utilizing cable television networks for the delivery of a variety of services to residential customers. Specifically, this paper focuses on the technology, marketplace, and regulatory aspects of this new and expanding market.