A survey of performance enhancement of transmission control protocol (TCP) in wireless ad hoc networks

This Article is provided by the Brunel Open Access Publishing Fund - Copyright @ 2011 Springer OpenTransmission control protocol (TCP), which provides reliable end-to-end data delivery, performs well in traditional wired network environments, while in wireless ad hoc networks, it does not perform well. Compared to wired networks, wireless ad hoc networks have some specific characteristics such as node mobility and a shared medium. Owing to these specific characteristics of wireless ad hoc networks, TCP faces particular problems with, for example, route failure, channel contention and high bit error rates. These factors are responsible for the performance degradation of TCP in wireless ad hoc networks. The research community has produced a wide range of proposals to improve the performance of TCP in wireless ad hoc networks. This article presents a survey of these proposals (approaches). A classification of TCP improvement proposals for wireless ad hoc networks is presented, which makes it easy to compare the proposals falling under the same category. Tables which summarize the approaches for quick overview are provided. Possible directions for further improvements in this area are suggested in the conclusions. The aim of the article is to enable the reader to quickly acquire an overview of the state of TCP in wireless ad hoc networks.This study is partly funded by Kohat University of Science & Technology (KUST), Pakistan, and the Higher Education Commission, Pakistan

An Adaptive Time-Spread Multiple-Access Policy for Wireless Sensor Networks

Sensor networks require a simple and efficient medium access control policy achieving high system throughput with no or limited control overhead in order to increase the network lifetime by minimizing the energy consumed during transmission attempts. Time-spread multiple-access (TSMA) policies that have been proposed for ad hoc network environments, can also be employed in sensor networks, since no control overhead is introduced. However, they do not take advantage of any cross-layer information in order to exploit the idiosyncrasies of the particular sensor network environment such as the presence of typically static nodes and a common destination for the forwarded data. An adaptive probabilistic TSMA-based policy, that is proposed and analyzed in this paper, exploits these idiosyncrasies and achieves higher system throughput than the existing TSMA-based policies without any need for extra control overhead. As it is analytically shown in this paper, the proposed policy always outperforms the existing TSMA-based policies, if certain parameter values are properly set; the analysis also provides for these proper values. It is also shown that the proposed policy is characterized by a certain convergence period and that high system throughput is achieved for long convergence periods. The claims and expectations of the provided analysis are supported by simulation results presented in this paper

Digging deeper: Research practices and recommendations for exploring intersectionality and social and cultural influences on personality, identity, and well-being

© 2016 Springer International Publishing Switzerland. This chapter integrates theoretical and empirical feminist work in order to assist personality researchers in exploring the psychosocial processes that shape personality, identity, and experience. First, I suggest that researchers theorize why patterns specific to particular social groups may occur. Second, I suggest that researchers must carefully consider who is included in the population they are studying and should attend to heterogeneity within these groups. Drawing on intersectionality as a theoretical framework, I suggest exploring individual, structural, and cultural factors that may account for variation both between individuals within a social group as well as between groups. This approach provides rich and detailed information that may be otherwise overlooked. I highlight three strategies that have the potential to assist psychologists in examining patterns of gender and identity among diverse groups and I illustrate these suggestions by drawing on examples from the literatures on aging, race/ethnicity, body image, and biopsychology. Together, these approaches can assist personality psychologists in fully articulating and investigating differences in their own right and emphasize the need to investigate how experiences of gender and other social categories shape and influence individual’s personality and well-being