关于搞好士官学员思想教育的几点思考

本文着重从士官学员的思想特点及其发展变化规律入手,研究如何针对这些特点和规律搞好思想教育工作。     

社交网站监管法律问题研究

本文着重分析了社交网站常见的法律问题,并通过比较研究各国的做法,试图总结出我国加强社交网站管理的监管措施。     

基于多处理器数据库系统的查询调度算法

提出一种多重查询调度算法——连续读取特性（CRP）调度算法,该算法应用连续读取特性,使查询的数据可以重组出某些连续关系,从而使之具有连续读取特性,解决了现有算法中有部分系统资源闲置的问题,提高查询速度。仿真实验结果表明,CRP调度算法的系统利用率和系统性能均优于其他算法。     

软件可靠性度量方法

分析软件故障暴露率与软件测试次数之间的关系,提出在保证可靠性测试结果客观准确的前提下,有效减少验证测试次数的方法。结合软件可靠性和体系结构相关理论,提出基于组件的软件失效率定量计算方法。研究并利用软件可靠性度量方法,提高了软件可靠性测试效率和可靠性评估准确性。     

HK网络演化模型的研究和改进

研究一种高集聚度的无标度网络模型,以Holme和Kim（HK）模型为基础,通过引进新增节点所应该具备的连接动态性,改进HK模型的局部特性。分析和仿真表明,改进模型HK’不仅继承了HK模型的高聚类效应和无标度特性,且它的幂律指数可在2～3之间变化,网络成员间的竞争机制也与现实社会网络较接近。     

无线传感器网络整合时钟同步方案

针对多数无线传感器网络时钟同步方案存在的仅纠正时钟偏移问题,提出一种新的解决方案,整合时钟偏移同步和时钟速率同步,通过3个连续的消息传输实现单跳同步,采用分层的生成树实现多跳同步。仿真实验结果表明,与现有的同步方案比较,该方案的同步错误更小,能够获得更长的再同步周期。     

Optimal replacement policy for a two-dissimilar-component cold standby system with different repair actions

In this paper, a cold standby repairable system consisting of two dissimilar components and one repairman is studied. When failures occur, the repair of both component 1 and component 2 are not ‘as good as new’. The consecutive operating times of component 1 after repair constitute a decreasing geometric process, while the repair times of component 1 are independent and identically distributed. For component 2, its failure is rectified by minimal repair, and the repair time is negligible. Component 1 has priority in use when both components are good. The replacement policy N is based on the failure number of component 1. Under policy N, we derive the explicit expression of the long-run average cost rate C(N) as well as the average number of repairs of component 2 before the system replaced. The optimal replacement policy N*, which minimises the long-run average cost rate C(N), is obtained theoretically. If the failure rate r(t) of component 2 is increasing, the existence and uniqueness of the optimal policy N* is also proved. Finally, a numerical example is given to validate the developed theoretical model. Some sensitivity analyses are provided to show the influence of some parameters, such as the costs for replacement and repair, and the parameters of the lifetime and repair time distributions of both components, to the optimal replacement policy N* and corresponding average cost rate C(N*).     

On detecting active worms with varying scan rate

Active worms have posed a major security threat to the Internet and many research efforts have focused on them. However, defending against them remains challenging due to their continuous evolution. In this paper, we study a new class of defense-oriented evolved worms, the Varying Scan Rate worm (the VSR worm in short). In order to circumvent detection by existing worm detection schemes, the VSR worm deliberately varies its scan rate according to these schemes’ weaknesses. To counteract the VSR worm, we design a new worm-detection scheme, the attack-target Distribution Entropy-based Dynamic detection scheme (DED detection for short). DED detection utilizes the attack-target distribution and robust statistical feature in conjunction with dynamic decision adaptation to distinguish worm-scan traffic from non-worm-scan traffic. We present a comparatively complete space of detection schemes and conduct extensive performance evaluations on the DED detection scheme compared with other schemes, using real-world Internet traces as background scan traffic. Our data clearly demonstrate the effectiveness of the DED detection scheme in detecting both the VSR worm and the traditional worm.     

On the estimation of adequate test set size using fault failure rates

Test set size in terms of the number of test cases is an important consideration when testing software systems. Using too few test cases might result in poor fault detection and using too many might be very expensive and suffer from redundancy. We define the failure rate of a program as the fraction of test cases in an available test pool that result in execution failure on that program. This paper investigates the relationship between failure rates and the number of test cases required to detect the faults. Our experiments based on 11 sets of C programs suggest that an accurate estimation of failure rates of potential fault(s) in a program can provide a reliable estimate of adequate test set size with respect to fault detection and should therefore be one of the factors kept in mind during test set construction. Furthermore, the model proposed herein is fairly robust to incorrect estimations in failure rates and can still provide good predictive quality. Experiments are also performed to observe the relationship between multiple faults present in the same program using the concept of a failure rate. When predicting the effectiveness against a program with multiple faults, results indicate that not knowing the number of faults in the program is not a significant concern, as the predictive quality is typically not affected adversely.