18,750 research outputs found
Alleviate exposed node issues in Wireless Mesh Network (WMN) using a novel approach of Concurrent Medium Access Control (C-MAC) protocol
The importance and high growth of the communication infrastructure is clearly stated under the Malaysia Economic Transformation Programme (ETP). The most popular technology that used to provide the internet service to public is the IEEE 802.11a/b/g/n based WiFi. However, the coverage provided by the WiFi technology is only limited up to certain range. In addition, the performance of the WiFi network also will become poorer and poorer as the number of users associate with that WiFi network increases. In order to address these issues, the best topology configuration known as mesh is proposed by wireless research community. This technology is also called as Wireless Mesh Networks (WMN) and it became an emerging technology which is plays an important role in the next generation wireless communication. However, the implementation of IEEE 802.11 Medium Access Control (MAC) protocol in WMN significantly degrades the network performance due to the presence of exposed node problem. The presence of exposed nodes in WMN caused waiting delay (prevent the surrounding neighboring nodes to involve in transmission activity for entire duration of ongoing transmission) and it is subsequently leads to poor throughput achievement. The significance of this research is to investigate the cause of exposed nodes that degrade the performance of WMN and proposed a novel protocol to solve it to provide better network performance and throughput
Android Permissions Remystified: A Field Study on Contextual Integrity
Due to the amount of data that smartphone applications can potentially
access, platforms enforce permission systems that allow users to regulate how
applications access protected resources. If users are asked to make security
decisions too frequently and in benign situations, they may become habituated
and approve all future requests without regard for the consequences. If they
are asked to make too few security decisions, they may become concerned that
the platform is revealing too much sensitive information. To explore this
tradeoff, we instrumented the Android platform to collect data regarding how
often and under what circumstances smartphone applications are accessing
protected resources regulated by permissions. We performed a 36-person field
study to explore the notion of "contextual integrity," that is, how often are
applications accessing protected resources when users are not expecting it?
Based on our collection of 27 million data points and exit interviews with
participants, we examine the situations in which users would like the ability
to deny applications access to protected resources. We found out that at least
80% of our participants would have preferred to prevent at least one permission
request, and overall, they thought that over a third of requests were invasive
and desired a mechanism to block them
Exposure to radio-frequency electromagnetic waves alters acetylcholinesterase gene expression, exploratory and motor coordinationlinked behaviour in male rats
Humans in modern society are exposed to an ever-increasing number of electromagnetic fields (EMFs) and some
studies have demonstrated that these waves can alter brain function but the mechanism still remains unclear.
Hence, this study sought to investigate the effect of 2.5 Ghz band radio-frequency electromagnetic waves (RFEMF)
exposure on cerebral cortex acetylcholinesterase (AChE) activity and their mRNA expression level as well
as locomotor function and anxiety-linked behaviour in male rats. Animals were divided into four groups namely;
group 1 was control (without exposure), group 2–4 were exposed to 2.5 Ghz radiofrequency waves from an
installed WI-FI device for a period of 4, 6 and 8 weeks respectively. The results revealed that WiFi exposure
caused a significant increase in anxiety level and affect locomotor function. Furthermore, there was a significant
decrease in AChE activity with a concomitant increase in AChE mRNA expression level in WiFi exposed rats
when compared with control. In conclusions, these data showed that long term exposure to WiFi may lead to
adverse effects such as neurodegenerative diseases as observed by a significant alteration on AChE gene expression
and some neurobehavioral parameters associated with brain damage
Experimental optimization of exposure index and quality of service in WLAN networks
This paper presents the first real-life optimization of the Exposure Index (EI). A genetic optimization algorithm is developed and applied to three real-life Wireless Local Area Network scenarios in an experimental testbed. The optimization accounts for downlink, uplink and uplink of other users, for realistic duty cycles, and ensures a sufficient Quality of Service to all users. EI reductions up to 97.5% compared to a reference configuration can be achieved in a downlink-only scenario, in combination with an improved Quality of Service. Due to the dominance of uplink exposure and the lack of WiFi power control, no optimizations are possible in scenarios that also consider uplink traffic. However, future deployments that do implement WiFi power control can be successfully optimized, with EI reductions up to 86% compared to a reference configuration and an EI that is 278 times lower than optimized configurations under the absence of power control
The Effects of WiFi Network (2.45 GHz) on Rats with Induced Stroke Associated with an Increased Risk of Heart Attack
Introduction: Stroke and heart attack are the most common causes of death among humans. Troponin I, Creatine Kinae-MB (CK-MB) and Lactate Dehydrogenase (LDH) are the diagnostic markers of heart attack which can also be used as high risk biomarkers. WiFi is a cheap common technology which exposes its users to a spectrum of electromagnetic waves. Can weak electromagnetic waves affect human health?Materials and Methods: In this study, stroke in rats has been induced, and then they were exposed to WiFi waves (2.45 GHz) and finally were examined for the risk of heart attack through analyzing three enzyme biomarkers related to heart attack (Troponin I, CK-MB and LDH). Results: This study’s results confirm WiFi’s biological effects and shows WiFi’s contribution in stroke. WiFi2.45GHz exposure affects three cardiac enzyme markers of heart attack (LDH, Troponin I and CK-MB), considering the current data on WiFi exposure effects on the brain, heart and related enzymes.Conclusion: Some of the WiFi wave’s cellular targets include cell membrane, cellular proteins and enzymes. Despite all the data and reports on biological effects of electromagnetic fields, the range and rate of these effects has not yet been determined
A novel multipath-transmission supported software defined wireless network architecture
The inflexible management and operation of today\u27s wireless access networks cannot meet the increasingly growing specific requirements, such as high mobility and throughput, service differentiation, and high-level programmability. In this paper, we put forward a novel multipath-transmission supported software-defined wireless network architecture (MP-SDWN), with the aim of achieving seamless handover, throughput enhancement, and flow-level wireless transmission control as well as programmable interfaces. In particular, this research addresses the following issues: 1) for high mobility and throughput, multi-connection virtual access point is proposed to enable multiple transmission paths simultaneously over a set of access points for users and 2) wireless flow transmission rules and programmable interfaces are implemented into mac80211 subsystem to enable service differentiation and flow-level wireless transmission control. Moreover, the efficiency and flexibility of MP-SDWN are demonstrated in the performance evaluations conducted on a 802.11 based-testbed, and the experimental results show that compared to regular WiFi, our proposed MP-SDWN architecture achieves seamless handover and multifold throughput improvement, and supports flow-level wireless transmission control for different applications
Anti-Fall: A Non-intrusive and Real-time Fall Detector Leveraging CSI from Commodity WiFi Devices
Fall is one of the major health threats and obstacles to independent living
for elders, timely and reliable fall detection is crucial for mitigating the
effects of falls. In this paper, leveraging the fine-grained Channel State
Information (CSI) and multi-antenna setting in commodity WiFi devices, we
design and implement a real-time, non-intrusive, and low-cost indoor fall
detector, called Anti-Fall. For the first time, the CSI phase difference over
two antennas is identified as the salient feature to reliably segment the fall
and fall-like activities, both phase and amplitude information of CSI is then
exploited to accurately separate the fall from other fall-like activities.
Experimental results in two indoor scenarios demonstrate that Anti-Fall
consistently outperforms the state-of-the-art approach WiFall, with 10% higher
detection rate and 10% less false alarm rate on average.Comment: 13 pages,8 figures,corrected version, ICOST conferenc
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