Circularly Polarized Square Patch Antenna with Trimmed Corners Using Textile Material

ABSTRACT: In this paper a circularly polarized wearable antenna at 2.4 GHz has been proposed for navigation, military communication, body centric communication and medical emergency. Body centric communication is an important application in the field of wireless communication and since antenna can be implemented on textile material, hence it can be widely used for military communication also. The paper presents the design of the wearable antenna made by the use of jeans substrate textile material with thickness 1mm, dielectric constant 1.7 and loss tangent 0.02. To feed the antenna inset feeding with a quarter wave transformer has been used. The proposed antenna offers approx -20 dB reflection loss, approx 3.5 dB axial ratio and 29% antenna efficiency

Impact Factor: 3.145

ABSTRACT Adaptive filtering has become a spacious area of researcher since last few decades in the field of communication. Adaptive noise cancellation is an approach used for noise reduction in speech signal. The speech signal easily gets contaminated with background noise. Channel noise addition makes this speech signal even poorer. Speech signal and noise signal both change continuously with time, then to separate them only adaptive filtering is desirable. This paper deals with cancellation of noise on speech signal using two old (LMS and NLMS) and one new UNANR algorithm. The UNANR (Unbiased and Normalized Adaptive Noise Rejection) model does not contain any bias unit, and the coefficients are adaptively updated by using the steepest-descent algorithm. Two modulation techniques, AM and FM are applied separately in combination with two communication channels i.e. AWGN and Rician. Signal quality parameter PSNR and RMSE measured and compared with respect to SNR. The results show that the performance of the UNANR based algorithm is superior to that of the LMS algorithm in noise reduction

Voices from Children Themselves: Preliminary Results of a Qualitative Study of Aggressive Behaviours within the School Context

Abstract The disruptive, provocative and intentionally aggressive behaviours of children are one of the most challenging issues that teachers and schools face today This empirical study was undertaken in the Cretian context and was qualitative in nature. Dialogical counselling and dynamic assessment interviews were the methods employed. The study aimed to understand how a sample of 11 school aged children (6-12 years old), diagnosed with conduct disorders, experience their teachers', parents', and classmates' attitudes. In line with contemporary inclusive education research, and based on the social model of disability, the authors attempted to go beyond the aggressive symptoms and through the interviews give voice to these children in order to explore their social and emotional needs and difficulties. A series of interviews with parents and classroom teachers was also organised around each pupil in order to collect more information on the child's social-academic trajectory and behaviour, the family dynamics, and the school's coping strategies. Though extended and more rigorous research is needed, the findings of this study clearly suggest that there is a family history of traumatic experiences or highly dysfunctional relational patterns in all the children's cases. Additionally, this study speculates that traditional educational practices fail to properly understand and respond to these children's social and emotional needs and difficulties, and therefore seriously risk jeopardizing their interpersonal and school trajectory

Secure kNN Query Processing in Untrusted Cloud Environments: an Overview

ABSTRACT: Nowadays, data are stored to a third party in cloud environments and query processing is also done by the third party to reduce the expense to maintain the system. Although there are lots of advantages in using independent third parties in query processing, security problems become more crucial since we cannot completely trust the third parties which can be easily corrupted or malfunctioning. The security problems with untrusted third parties are multifaceted in several areas such as privacy, authentication, and recovery. For privacy, the third party should not be able to know what the user's query is since the query itself describes the user's interest. For authentication, the user should be able to verify that the information from the third party is not tampered since the correctness of the query results depends upon the correctness of the information from the third party. For recovery, when the result is found to be forged by an adversary, we should be able to find the adversary and get a correct result by removing the adversary. To address these challenges, we propose several schemes. First, with respect to secure kNN query processing and secure proximity detection, we give novel schemes based on Mutable Order Preserving Encryption (MOPE) and Secure Point Evaluation Method (SPEM). Second, for authenticated top-k aggregation, we suggest novel schemes using Three Phase Uniform Threshold Algorithm, Merkle Hash Tree, and Condensed-RSA. Third, for detecting malicious nodes, we propose novel algorithms based on Additively Homomorphic Encryption and Multipath Transmission. Our experimental evaluation and security analyses demonstrate that robust mechanisms can be deployed with a minimal amount of computational and communicational expense

Maximizing service reliability in distributed computing systems with random failures: Theory and implementation,”

Abstract-In distributed computing systems (DCSs) where server nodes can fail permanently with nonzero probability, the system performance can be assessed by means of the service reliability, defined as the probability of serving all the tasks queued in the DCS before all the nodes fail. This paper presents a rigorous probabilistic framework to analytically characterize the service reliability of a DCS in the presence of communication uncertainties and stochastic topological changes due to node deletions. The framework considers a system composed of heterogeneous nodes with stochastic service and failure times and a communication network imposing random tangible delays. The framework also permits arbitrarily specified, distributed load-balancing actions to be taken by the individual nodes in order to improve the service reliability. The presented analysis is based upon a novel use of the concept of stochastic regeneration, which is exploited to derive a system of difference-differential equations characterizing the service reliability. The theory is further utilized to optimize certain load-balancing policies for maximal service reliability; the optimization is carried out by means of an algorithm that scales linearly with the number of nodes in the system. The analytical model is validated using both Monte Carlo simulations and experimental data collected from a DCS testbed

Cultural distance, mindfulness and passive xenophobia: Using Integrated Threat Theory to explore home higher education students' perspectives on 'internationalisation at home'

This paper addresses the question of interaction between home and international students using qualitative data from 100 home students at two 'teaching intensive' universities in the southwest of England. Stephan and Stephan's Integrated Threat Theory is used to analyse the data, finding evidence for all four types of threat that they predict when outgroups interact. It is found that home students perceive threats to their academic success and group identity from the presence of international students on the campus and in the classroom. These are linked to anxieties around 'mindful' forms of interaction and a taboo around the discussion of difference, leading to a 'passive xenophobia' for the majority. The paper concludes that Integrated Threat Theory is a useful tool in critiquing the 'internationalisation at home' agenda, making suggestions for policies and practices that may alleviate perceived threats, thereby improving the quality and outcomes of intercultural interaction. © 2010 British Educational Research Association

A LONG-TERM, WATERSHED-SCALE, EVALUATION OF THE IMPACTS OF ANIMAL WASTE BMPs ON INDICATOR BACTERIA CONCENTRATIONS1

ABSTRACT: Driven by increasing concerns about bacterial pollution from agricultural sources, states such as Virginia have initiated cost sharing programs that encourage the use of animal waste best management practices (BMPs) to control this pollution. Although a few studies have shown that waste management BMPs are effective at the field scale, their effectiveness at the watershed scale and over the long term is unknown. The focus of this research was to evaluate the effectiveness of BMPs in reducing bacterial pollution at the watershed scale and over the long term. To accomplish this goal, a 1,163 ha watershed located in the Piedmont region of Virginia was monitored over a ten-year period. Fecal coliforms (FC) and fecal streptococci (FS) were measured as indicators of bacterial pollution. A pre-BMP versus post-BMP design was adopted. Major BMPs implemented were manure storage facilities, stream fencing, water troughs, and nutrient management. Seasonal Kendall trend analysis revealed a significant decreasing trend during the post-BMP period for FC concentrations at the watershed outlet, but not at the subwatershed level. Implementation of BMPs also resulted in a significant reduction in the geometric mean of FS concentrations. FC concentrations in streamflow at the watershed outlet exceeded the Virginia primary standard 86 and 74 percent of the time during pre-BMP and post-BMP periods, respectively. Corresponding exceedances for the secondary standard were 50 and 41 percent. Violations decreased only slightly during the post-BMP period. The findings of this study suggest that although BMP implementation can be expected to accomplish some improvement in water quality, BMP implementation alone may not ensure compliance with current water quality standards. (KEY TERMS: nonpoint source pollution; watershed management; water quality; bacterial pollution; fecal coliform; fecal streptococcus; BMP.) INTRODUCTION Contamination from bacterial sources has been identified as the third leading cause of pollution in the nation's rivers, after siltation and nutrients (USEPA, 1999). Pollution from bacteria accounts for nearly 79,820 impaired river miles or 12 percent of the total river miles surveyed in the United States (USEPA, 1999). In Virginia, fecal contamination of surface waters is the leading pollution problem, and agriculture has been cited as the largest contributor of this pollutant (USEPA, 1999). Land application of animal wastes and runoff from livestock facilities are the major agricultural practices contributing to bacterial pollution Although several studies and reviews have evaluated bacterial pollution from agricultural land