University of Memphis

About: University of Memphis is a education organization based out in Memphis, Tennessee, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 7710 authors who have published 20082 publications receiving 611618 citations. The organization is also known as: U of M.

Voice capacity analysis of WLAN with unbalanced traffic

Abstract: An analytical model to study the performance of wireless local area networks (WLANs) supporting asymmetric nonpersistent traffic using the IEEE 802.11 distributed coordination function mode for medium access control (MAC) is developed. Given the parameters of the MAC protocol and voice codecs, the voice capacity of an infrastructure-based WLAN, in terms of the maximum number of voice connections that can be supported with satisfactory user-perceived quality, is obtained. In addition, voice capacity analysis reveals how the overheads from different layers, codec rate, and voice packetization interval affect voice traffic performance in WLANs, which provides an important guideline for network planning and management. The analytical results can be used for effective call admission control to guarantee the quality of voice connections. Extensive simulations have been performed to validate the analytical results

The heat equation with generalized Wentzell boundary condition

Abstract: Let Ω be a bounded subset of RN, \( a \in C^1(\overline\Omega) \) with \( a>0 \) in Ω and A be the operator defined by \( Au := abla\cdot (a abla u) \) with the generalized Wentzell boundary condition.¶¶\( Au + \beta\frac{\partial u}{\partial n} + \gamma u=0\qquad \hbox{on} \quad\partial \Omega. \)¶¶If \( \partial\Omega \) is in C2, β and γ are nonnegative functions in \( C^1(\partial\Omega), \) with β > O, and \( \Gamma:=\{x\in\partial\Omega: a(x)>0\} eq\emptyset \), then we prove the existence of a (C0) contraction semigroup generated by \( \overline{A} \), the closure of A, on a suitable Lp space, \( 1\le p $<$\infty \) and on \( C(\overline{\Omega}).\) Moreover, this semigroup is analytic if \( 1 $<$ p $<$\infty. \)

Mind wandering while reading easy and difficult texts

Abstract: Mind wandering is a phenomenon in which attention drifts away from the primary task to task-unrelated thoughts. Previous studies have used self-report methods to measure the frequency of mind wandering and its effects on task performance. Many of these studies have investigated mind wandering in simple perceptual and memory tasks, such as recognition memory, sustained attention, and choice reaction time tasks. Manipulations of task difficulty have revealed that mind wandering occurs more frequently in easy than in difficult conditions, but that it has a greater negative impact on performance in the difficult conditions. The goal of this study was to examine the relation between mind wandering and task difficulty in a high-level cognitive task, namely reading comprehension of standardized texts. We hypothesized that reading comprehension may yield a different relation between mind wandering and task difficulty than has been observed previously. Participants read easy or difficult versions of eight passages and then answered comprehension questions after reading each of the passages. Mind wandering was reported using the probe-caught method from several previous studies. In contrast to the previous results, but consistent with our hypothesis, mind wandering occurred more frequently when participants read difficult rather than easy texts. However, mind wandering had a more negative influence on comprehension for the difficult texts, which is consistent with the previous data. The results are interpreted from the perspectives of the executive-resources and control-failure theories of mind wandering, as well as with regard to situation models of text comprehension.

The influence of ethical climate and ethical conflict on role stress in the sales force

Abstract: Several leading models of ethical decision making include factors contributing to an organization’s ethical climate as significant determinants affecting ethical choice. The relationship of ethical climate to ethical conflict and role conflict is examined in a salesperson context. Results suggest that salespersons’ perceptions of a positive ethical climate are negatively associated with their perceived ethical conflict with sales managers. Implications and directions for future research are provided.

Methods to reduce the impact of intraclass correlation in group-randomized trials

Abstract: This study reports intraclass correlation (ICC) for dependent variables used in group-randomized trials (GRTs). The authors also document the effect of two methods suggested to reduce the impact of ICC in GRTs; these two methods are modeling time and regression adjustment for covariates. They coded and analyzed 1,188 ICC estimates from 17 published, in press, and unpublished articles representing 21 studies. Findings confirm that both methods can improve the efficiency of analyses shown to be valid across conditions common in GRTs. Investigators planning GRTs should obtain ICC estimates matched to their planned analysis so that they can size their studies properly.