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In recent years, the wireless sensor network (WSN) has become more and more popular, and the problem of WSN localization has attracted great attention. In non-line of sight (NLOS) propagation conditions, the localization is less accurate than in line of sight (LOS) propagation conditions because of the buildings between the mobile station and the base station obstruct the spread of waves. In order...
The importance of regression testing in assuring the integrity of a program after changes is well recognized. One major obstacle in practicing regression testing is in maintaining tests that become obsolete due to evolved program behavior or specification. For mobile apps, the problem of maintaining obsolete GUI test scripts for regression testing is even more pressing. Mobile apps rely heavily on...
Mobile Assisted Language Learning (MALL) delivers the content of learning to the audience with the mobile computing devices such as laptops, smart phones and handheld devices. The advantage of MALL approach is that learners are not restricted to time, place and the presence of the teachers. This paper will discuss ways in which mobile computing devices can be used for aviation English learning with...
In this paper, we can find the defects of the security mechanism through the analysis of the security mechanism of iOS system. And in accordance with known vulnerabilities, we achieve to exploit the loopholes, and then complete the breaking out of sandbox, Obtaining arbitrary code executio, root privilege, patching kernel. Finally we achieve to jailbreak the iOS system.
Using the large amount of data collected by mobile operators to evaluate network performance and capacity is a promising approach developed in the recent last years. One of the challenge is to study network accessibility, based on statistical models and analytics. In particular, one aim is to identify when mobile network becomes congested, reducing accessibility performance for users. In this paper,...
Recently, mobility-enabled wireless sensor networks have been exploited to improve energy efficiency at the cost of increased latency. In this paper, we propose a Grid-based solution for Real-time Data Gathering application with mobile sinks (GRDG). Like many hierarchical structures, the flexible virtual grid partition scheme based on power control is designed to enhance network scalability, reduce...
This paper solves the problem of localization of mobile node in mixed line-of-sight/non-line-of-sight (LOS/NLOS) environments. To improve the localization accuracy, a parallel Kalman filtering algorithm is proposed to locate the robot mobile node. This algorithm consists of two steps: We firstly calculate the LOS/NLOS mode probabilities, then the proposed algorithm combines the estimation results...
Securing communication in mobile wireless networks is challenging because the traditional cryptographic-based methods are not always applicable in dynamic mobile wireless environments. Using physical layer information of radio channel to generate keys secretly among wireless devices has been proposed as an alternative in wireless mobile networks. And the Received Signal Strength (RSS) based secret...
Recently the disconnected Delay-Tolerant Network (DTN) draws more and more attention.It is different from the traditional Ad-hoc and MANET. In DTN the disconnected nature and lack of end to end connectivity between nodes mean that the nodes communicate by the way of store-carry-forward. Therefore, it was rencently been recognized that mobility can be turn into a useful ally, by making nodes carry...
In this paper, we adopt the DMT framework to study a cooperative downlink OFDMA system with multiple relays. We derive the closed-form expression of the DMT curve for the cooperative OFDMA system employing linear constellation precoding at the base station, and linear detection at the mobile users, and develop the optimal symbol loading, relay selection and subcarrier allocation strategy. Simulation...
Under the assumption of single bounce channel model, the position and velocity of a mobile station (MS) can be determined by time of arrival (TOA), angle of arrival (AOA) and doppler-shifted frequency (DSF) measurements at three base stations (BSs) when line of sight (LOS) paths between the three BSs and the MS are all blocked. The equations relating the measured TOAs, AOAs and DSFs to the location...
The available bandwidth information is important to the admission control, channel scheduling and other schemes; moreover, it is an important parameter to evaluate the quality of service in Mobile Ad Hoc network. With analysis of the difference between bandwidth estimation scheme in wired network and wireless network, the available bandwidth in Mobile Ad Hoc network is defined. The factors which infect...
The LTE-Advanced (LTE-A) system is currently under development to allow for significantly higher spectral efficiency and data throughput than LTE systems. In a wireless system based on orthogonal frequency division multiplexing (OFDM) with frequency reuse factor one such as LTE, the achievable cell spectral efficiency is often limited by the inter-cell interference or coverage shortage of base stations...
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