Earticle

Software visualization techniques fall into two categories: visualization of software component relationships and visualization of software metrics. In this paper, we propose a new hybrid method based on both categories. The proposed method visualizes the coincidence between specification and implementation from two aspects: static checking and ordinal testing by test suites. In our method, each ratio of the coincidence is shown by pie charts which represent classes of the target software. The whole software is represented in a weighted digraph structure. We have prototyped a tool to implement our proposed method. We have evaluated the utility of the proposed method by applying the tool to two kinds of software: a warehouse management program and a telephone directory management program. We conclude that the proposed method yields informative results.

When under lower temperature state such as in the winter, power battery of the electric car has lower capacity which is easily decreased and even damaged. So it is necessary to preheat the battery before using. To understand the preheating process, simulation of temperature rising of power battery is carried out under several conditions of forced convection. The properties of temperature rising in preheating process of the battery under different air velocities and temperatures are discussed.

Under the development of the self organizing network (SON) for long term evolution (LTE) systems, the radio resource management (RRM) with suitable frequency reuse technique is a vital factor in providing the required performance for future applications especially in the case of convergence of networks and services. A way to improve the scheduling process of the physical radio resource blocks (PRBs) should be considered to increase the network throughput and to achieve better quality of service (QoS) and fairness to the users. In this paper, some important aspects related to RRM are discussed, and a new channel quality indicator (CQI) concept based on a simple feedback technique is presented. This method creates an alternative vision for the geometry factor to employ the selective frequency reuse technique inside the network cells.

With the development of virtualization technology, some security problems have appeared. Researchers have begun to suspect the security of virtualized environments and to consider how to evaluate the degree of their security. But there are no uniform virtualized environment security evaluation criteria at present. In this paper, we analyse the security problem in virtualized environments and present our criteria. We further research its support technology and authentication methods. First, we introduce the background of the problem. Next, we summarize the related work. After that we present our virtualized environment security evaluation criteria and introduce our work on support technology and authentication method. For support technology, we propose some safety guarantee technology for each security level. For authentication method, we give some ideas for the evaluation of each security level.

Mobile computing is becoming a widespread working tool, and as a large scale deployed technology, it should be strong enough to meet basic security expectations. Privacy in a mobile environment should be driven by the choice of appropriate identity management mechanisms, that will have a large impact on different aspects of daily life. Since people are unable to spend all their time administering their digital identities, the implementation of mobile identity management technologies has become a top priority for the involved companies, in order to protect their customers against fraudsters. Today, identity management and strong authentication are converging, since the provided solutions encompass user access, signing and verification of users and transactions through strong authentication. However, simply using strong authentication will not resolve all mobile digital identity requirements from a security viewpoint. Hence, our objective is to propose an extensible protocol based on an independent architectural model that provides a foundation for user-centric identity management.

One of the concerns users have to confront when using an IPTV system is information overload, which makes it difficult for them to find suitable content according to their personal preferences. A recommendation service is one of the most widely adopted technologies for alleviating this problem; these services intend to provide people with referrals of items that they will appreciate based upon their preferences. IPTV users must ensure that their sensitive preferences collected by any recommendation service are properly secured. In this work, we introduce a framework for a private recommender service based on Enhanced Middleware for Collaborative Privacy (EMCP). EMCP executes a two-stage concealment process that gives the user complete control over the privacy level of his profile. We utilise a trust mechanism to augment the recommendation’s accuracy and privacy. These trust heuristic spot users whom are trustworthy with respect to the user requesting the recommendation (target-user). Later, the neighbourhood formation is calculated using proximity metrics based on these trustworthy users. Finally, users submit their profiles in an obfuscated form without revealing any information about their data, and the computation of recommendations proceeds on the obfuscated data using a secure multi-party computation protocol. We expand the obfuscation scope from a single obfuscation level for all users to arbitrary obfuscation levels based on different trust levels between users. In other words, we correlate the obfuscation level with different levels of trust, so the more trusted a target user is, the less obfuscatedcopy of users’ profiles he can access. We also provide an IPTV network scenario and experimentation results. Our results and analysis show that our two-stage concealment process not only protects the users’ privacy, but can also maintain the accuracy of the recommendations.

This paper addresses the question of whether or not the specific packet/frame lost, and in particular, its position relative to the I-frames, influences the quality of transmitted compressed video. We focus on the QCIF size video frame, one of the most pervasive video formats used across the Internet and cellular systems. Using the average Peak Signal to Noise Ratio (PSNR) of the received coded video to measure the amount of distortion, we demonstrate that the interval between the lost frame and the last I-frame does have a significant effect on quality. Furthermore, after investigating the probability of different burst loss lengths in noisy environments where the duration of data loss is almost constant, we propose a method for improving the performance of video streaming over noisy channels based on packet scheduling, without an increase in the bit rate.