Performance Analysis of WiMAX Networks AC

In WiMAX networks, contention based bandwidth requests are allowed in the uplink channel on the time division duplexing frame. The standard allows some types of traffic classes to use this period while preventing others like Unsolicited Grant Service. In this study, we provide a performance analysis of the three types of connections (ertPS, non-real time Polling Service and Best Effort) that are allowed to contend for bandwidth request opportunities. The choice of these traffic classes covers both real and non-real traffic types. Two quality of service parameters; contention probability and average connection delay are investigated in order to evaluate the network performances. Different levels of priority and blocking probability are assigned to each class of service. This performance analysis has been done using an analytical model for evaluating admission control for the previous mentioned classes in WiMAX network.     

The Limits to Authority: Developer Interventions and Neighbour Problems on a Master Planned Estate

Master planned estates are large suburban developments built by a private sector developer. As part of its pursuit of building ready-made communities, the Developer becomes active in the management of the estate for years after its completion, subsequently finding itself in the difficult position of running, rather than simply building, new communities. In this paper, this challenge facing the Developer is explored with reference to Foucault’s writing on the problematics of governing under liberalism and the question of what is within the competence of the state and what is not. This paper shows how corporate property developers pose themselves similar questions and face the effects of demarcating certain spheres of residential life as not within their domain. The example addressed here is the issue of managing problems between neighbours and the tensions arising from residents’ expectations that this is indeed a matter of development control.     

A longitudinal examination of familial risk factors for depression among inner-city African American adolescents.

This research examines longitudinally associations between family risk factors and child and parent depression in 302 urban, low-income, African American adolescents (ages 9-15) and their parents across 2 waves of data collection. Diagnostic data revealed that 7.3% of parents and 3.0% of children at Time 1 and 5.4% of parents and 2.8% of children at Time 2 were clinically depressed. Regression analyses revealed that changes in family functioning were concurrently associated with changes in depression for both children and parents. Specifically, increases in conflict and decreases in parental monitoring were associated with increases in child depressive symptomatology, and increases in conflict and decreases in positive parenting were associated with increases in parental depressive symptomatology. Findings are discussed within a framework of understanding family protective factors and the prevention of depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An anion exchange resin from soybean hulls

Agricultural by‐products are generally poor adsorbents of anions in solution. Therefore, modification of the by‐product could enhance its anion exchange capabilities. The objective of this study was to increase the anion exchange properties of the agricultural by‐product, soybean hulls, by chemical modification. Soybean hulls were quaternized with the quaternizing agent, N‐(3‐chloro‐2‐hydroxypropyl) trimethylammonium chloride, in the presence of a strongly alkaline environment. This modification increased the amount of positive charge on the hulls as evidenced by increased nitrogen content and increased uptake of anions compared with the unmodified hulls. A method to optimize the anion exchange properties of the hulls was developed. Ion exchange properties of the hulls toward anions of environmental significance, namely arsenate (As), chromate (Cr), dichromate (Cr₂), phosphate (P) and selenate (Se) were determined. The modified hulls were also compared with commercial cellulose‐based and synthetic anion exchange resins in their ability to remove these anions from solution. The experimental and commercial resins were also compared for their ability to remove a mixture of arsenate, chromate, dichromate and selenate from laboratory prepared solutions to levels below the maximum contaminant levels for these anions in drinking water as specified by the US Environmental Protection Agency (US EPA). Our results demonstrate that the soy hull resin is more efficient in anion removal than the commercial cellulose‐based resin but not as effective as the commercial synthetic resin. Published in 2003 for SCI by John Wiley & Sons, Ltd.     

Academic crime and punishment: Faculty members' perceptions of and responses to plagiarism.

Academic dishonesty and its consequences have become increasingly complex. Highly accessible electronic media, profound consequences for misconduct and reporting, and lack of standard practice intensify the issues. We surveyed 270 faculty members to determine whether they had been confronted with plagiarism and if they felt prepared to deal with it. Using case studies, we examined faculty characterizations of the severity of students' uncited use of another's work, and their suggested actions, reports, and sanctions, by source, use, and amount of material. In addition to multiple interactions, we found that faculty members' perceptions of severity strongly mediate the consequences they recommend. However, within-case, recommended consequences (e.g., course actions, reports and sanctions) vary widely. Implications for development of guidelines based on level of plagiarism are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Warriors as peacekeepers: Features of the Somalia experience and PTSD.

There has been scant empirical study of the psychological consequences of contemporary peacekeeping missions. This study examined relationships among 4 variables characterizing this type of operation (traditional combat events, negative aspects of peacekeeping, pressure to uphold restraint, and positive aspects of peacekeeping) and symptoms of posttraumatic stress disorder (PTSD). Participants were 3,310 male and female soldiers who served in the 1992–1994 Somalia mission. Structural equation modeling procedures were applied to data from subsamples of non-African Americans and African Americans. For both groups, traditional combat and negative aspects of peacekeeping were associated with PTSD, frustration with restraint, and positive aspects of peacekeeping; however, restraint was not related to PTSD. Discrepancies between the groups involved relationships among the restraint, positive aspects, and PTSD variables. Recommendations are offered to foster inquiry into this new research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role conflict and role ambiguity: A critical assessment of construct validity.

This article appraises the construct validity of role conflict and role ambiguity in organizational psychology research by tracing the process of validation from initial theory introduction to the present. Although the theoretical bases for the constructs were relatively well explicated, some conceptual shortcomings have carried over into empirical work. There are problems with the content validity of measures, a lack of convergent and discriminant evidence, and inattention to the full nomological network of hypothesized relationships. Recommendations for future role-conflict and role-ambiguity research are offered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Imposed differences in comparative ratings.

Hypothesized that if objects are perceived as similar on the rating dimension but as different on other important dimensions, imbalance will be created. It is predicted that this imbalance will be resolved by imposing differences between the ratings of the objects. If, however, the S is first allowed an adequate means of expressing the differences between the objects, there will be no need to impose differences between the objects on the nondiscriminating scale. 25 noun pairs were generated with both a discriminating and a nondiscriminating scale. Three forms were used with 302 college students. On the first form, the rating of the 2 nouns was taken independently on the nondiscriminating scale. On the second form, Ss rated the noun pairs simultaneously on the nondiscriminating scale, whereas on the third form, Ss rated them simultaneously on both the discriminating and the nondiscriminating scales. Results support the theory. The separation between the nouns was significantly greater when rated simultaneously than when rated independently, and the separation between noun pairs was reduced when Ss had both a discriminating and a nondiscriminating scale on which to rate. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Silicon solar cells for terrestrial applications

The ways in which silicon solar cells can be designed to give maximum efficiency are reviewed. It is suggested that, although the reduction of processing costs is an extremely important objective of the development programme aimed at widespread application in highly developed countries, the improvement of design might have sufficient cost benefit even if based on current processing technology for the application of solar cells in remote localities which are not easily served with electricity via transmission lines.