Optical wireless localization

In this paper, we explore the possibility of using directionality of free-space-optical (a.k.a. optical wireless) communications for solving the 3-D localization problem in ad-hoc networking environments. Range-based localization methods either require a higher node density (i.e., at least three other localized neighbors must exist) than required for assuring connectedness or a high-accuracy power-intensive ranging device such as a sonar or laser range finder which exceeds the form factor and power capabilities of a typical ad-hoc node. Our approach exploits the readily available directionality information provided by a physical layer using optical wireless and uses a limited number of GPS-enabled nodes, requiring a very low node density (2-connectedness, independent of the dimension of space) and no ranging technique. We investigate the extent and accuracy of localization with respect to varying node designs (e.g., increased number of transceivers with better directionality) and density of GPS-enabled and ordinary nodes as well as messaging overhead per re-localization. Although denser deployments are desirable for higher accuracy, our method still works well with sparse networks with little message overhead and small number of anchor nodes (as little as 2). We also present a proof-of-concept prototype of our FSO-based localization techniques and show the validity of our approach even with three transceivers per node.     

Alcohol breeds empty goal commitments.

According to alcohol-myopia theory (C. M. Steele & R. A. Josephs, 1990), alcohol leads individuals to disproportionally focus on the most salient aspects of a situation and to ignore peripheral information. The authors hypothesized that alcohol leads individuals to strongly commit to their goals without considering information about the probability of goal attainment. In Study 1, participants named their most important interpersonal goal, indicated their expectations of successfully attaining it, and then consumed either alcohol or a placebo. In contrast to participants who consumed a placebo, intoxicated participants felt strongly committed to their goals despite low expectations of attaining them. In Study 2, goal-directed actions were measured over time. Once sober again, intoxicated participants with low expectations did not follow up on their strong commitments. Apparently, when prospects are bleak, alcohol produces empty goal commitments, as commitments are not based on individuals’ expectations of attaining their goals and do not foster goal striving over time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A cultural task analysis of implicit independence: Comparing North America, Western Europe, and East Asia.

Informed by a new theoretical framework that assigns a key role to cultural tasks (culturally prescribed means to achieve cultural mandates such as independence and interdependence) in mediating the mutual influences between culture and psychological processes, the authors predicted and found that North Americans are more likely than Western Europeans (British and Germans) to (a) exhibit focused (vs. holistic) attention, (b) experience emotions associated with independence (vs. interdependence), (c) associate happiness with personal achievement (vs. communal harmony), and (d) show an inflated symbolic self. In no cases were the 2 Western European groups significantly different from one another. All Western groups showed (e) an equally strong dispositional bias in attribution. Across all of the implicit indicators of independence, Japanese were substantially less independent (or more interdependent) than the three Western groups. An explicit self-belief measure of independence and interdependence showed an anomalous pattern. These data were interpreted to suggest that the contemporary American ethos has a significant root in both Western cultural heritage and a history of voluntary settlement. Further analysis offered unique support for the cultural task analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automatic realignment with electronic steering of free-space-optical transceivers in MANETs: A proof-of-concept prototype

Free-Space-Optical (FSO) communication has the potential to achieve very high wireless communication rates at tens of GHz. Although it has the advantage of high-speed optical modulation, FSO communication is prone to mobility and it requires establishment and maintenance of line-of-sight (LOS) between FSO transceivers since FSO transceivers are highly directional. We consider FSO structures with multiple transceivers placed on a spherical shape with angular diversity and tackle the problem of automatically detecting and maintaining LOS alignment among neighbor multi-transceiver FSO structures. We present a prototype implementation of such multi-transceiver electronically-steered communication structures. Our prototype uses a simple LOS detection and establishment protocol and assigns logical data streams to appropriate physical links. We show that by using multiple directional transceivers and an auto-alignment mechanism, it is possible to maintain optical wireless links in a mobile setting with minimal disruptions and overhead.