Liao Xiangke

Energy efficient multipath routing using network coding in wireless sensor networks

Multipath is a sought-after mechanism to achieve reliability along the error-prone channel in wireless sensor networks. However, this technique is not energy efficient since sensor networks are subject to strict resource constraints. In this paper, we propose an energy aware method to combine multipath routing with practical network coding technique. Through this method, we can guarantee the same reliability while reduce much energy consumption by decreasing the number of paths needed to delivery data. This method only needs little metadata overhead and some small-scale linear operations. Simulations under different circumstances verify the theoretical results. The paper also discusses other advantages of network coding in multi-receiver case to illustrate our future work.Multipath is a sought-after mechanism to achieve reliability along the error-prone channel in wireless sensor networks. However, this technique is not energy efficient since sensor networks are subject to strict resource constraints. In this paper, we propose an energy aware method to combine multipath routing with practical network coding technique. Through this method, we can guarantee the same reliability while reduce much energy consumption by decreasing the number of paths needed to delivery data. This method only needs little metadata overhead and some small-scale linear operations. Simulations under different circumstances verify the theoretical results. The paper also discusses other advantages of network coding in multi-receiver case to illustrate our future work.

Credit based Fairness Control in Wireless Sensor Network

Fairness is an essential problem in congestion control, which is to ensure all data sources have equal or weighted access to end-to-end network bandwidth. In this paper, we propose a practical fairness model CFRC to allocate congested bandwidth based on the credit of each sensor source instead of uniformly. Credit represents the effective amount of sensed information of packet generated in sensor source. In CFRC, a low-cost credit computation method ACCA is proposed for each source node to compute its credit locally based on the sensed area of it and its neighbors; Aggregation node computes the credit of aggregated packets using simple sum operation. Furthermore, an interferer aware fair rate allocation algorithm IFRA is proposed in CFRC to allocated bandwidth not only among all upstream neighbors, but also among congested nodes and its interferers. Simulation results verify the performance of CFRC.

Feedback control with prediction for thread allocation in pipeline architecture web server

With the sharply development of high-speed backbone network and phenomenal growth of Web applications, many kinds of Web server structures have been advanced and implemented to increase the serving ability of Web server. In this paper, we propose a pipeline architecture multi-thread web server open KETA which divides the requests processing into several independent phases. This architecture reduces parallelism granularity and achieves inner-request parallelism to enhance its processing capability. Furthermore, a combined feed-forward/feedback model is designed to manage thread allocation in this special architecture. The feed-forward predictor relates instantaneous measurements of queue length and processing rate of each pipeline phase to the thread allocation over a finite prediction horizon. The feedback controller deals with the uncertainty the predictor brings and improves open KETAs performance farther. Experimental results show the capability of open KETA and the effectiveness of the thread allocation model.

Research on control flags-based weighted authentication trustworthiness model

In this paper, weighted factors are given to authentication rules to express their importance, and the control flags are given to multiple authentication rules to express their stack relationship and reflect their effect on the authentication conclusions. Based on the research on weighted model in fuzzy logic, this paper puts forwards the control flags-based weighted authentication trustworthiness model. The model firstly calculates the trustworthiness of a single weighted authentication rule, then, according to the control flags corresponding to each authentication rule, calculates the users authentication trustworthiness under multiple authentication rules. By comparing users authentication trustworthiness with system access trustworthiness threshold, the system forms the final authentication conclusion. The model describes the uncertainties in authentication system comprehensively, and enhances the security under multiple authentication rules.

AT-PAM: an authentication trustworthiness-based PAM

In order to demonstrate the uncertainties in authentication system and the importance of different authentication mechanisms, this paper imports the uncertainty reasoning in expert system field, puts forwards the authentication trustworthiness factor model, then, this paper associates the authentication trustworthiness with PAM framework, puts forwards the authentication trustworthiness-based PAM (AT-PAM) framework. By authentication trustworthiness computing in AT-PAM framework, the framework gives the user his authentication trustworthiness. By comparing this value with the system logging trustworthiness threshold, the framework gives the final authentication decision. The framework keeps the advantages of PAM framework, solves the uncertainty problem in authentication system, and gives finegrained authentication control.

Automatic Type Inference for Proactive Misconfiguration Prevention.

Misconfigurations have become a major cause of software failures. Most research focuses on misconfiguration diagnosis and troubleshooting, which occur after the misconfigurations have happened. Actually, if we can prevent misconfiguration before software runs, many potential catastrophic failures of systems can be avoided, thus reducing customers’ downtime and support costs. In software configuration, we found that most configuration options have specific constraints, which have a strong connection with the configuration option type. If we can check the configuration settings against the inferred type before the software runs, many misconfigurations can be prevented. In this paper, we explore a name-based method called ConfTypeInferer to automatically infer the type of configuration options, which can help users to correctly configure and check settings, thus preventing misconfigurations proactively. We manually studied several popular open-source software projects to investigate the classification and naming conventions of configuration option. Based on these findings, we designed and implemented the ConfTypeInferer. We performed comprehensive experiments to evaluate the effectiveness of our method.

Emerging High-Performance Computing Systems and Technology

High-performance computing (HPC) technology is the strategic height of modern computing among countries in the current information era. This paper focuses on the challenges of emerging HPC technology in the future, and discusses the developing status and trends of HPC architecture, algorithms, and applications. From the viewpoint of foundation research, we propose significant research fields (or scientific issues), as well as related policies for HPC systems and technology in China.

Path selection of reliable data delivery in wireless sensor networks

Multipath is a sought-after mechanism to achieve reliability along the error-prone channel in wireless sensor networks. However, its benefits are not easily explored because the critical energy constraints and the multipath interference. In this paper, we first prove that finding several disjoint paths with minimum energy consumption is an NP-complete problem, then give the near-optimal solution on how to choose path based on the accurate energy model. Furthermore, we make use of the multi-frequency characteristic of CC2420 radio and propose IEMM-FA to minimize interference and energy consumption of multiple paths. Simulation results verify its performance.Multipath is a sought-after mechanism to achieve reliability along the error-prone channel in wireless sensor networks. However, its benefits are not easily explored because the critical energy constraints and the multipath interference. In this paper, we first prove that finding several disjoint paths with minimum energy consumption is an NP-complete problem, then give the near-optimal solution on how to choose path based on the accurate energy model. Furthermore, we make use of the multi-frequency characteristic of CC2420 radio and propose IEMM-FA to minimize interference and energy consumption of multiple paths. Simulation results verify its performance.

Access request trustworthiness in weighted access control framework

Weighted factor is given to access control policies to express the importance of policy and its effect on access control decision. According to this weighted access control framework, a trustworthiness model for access request is also given. In this model, we give the measure of trustworthiness factor to access request, by using some idea of uncertainty reasoning of expert system, present and prove the parallel propagation formula of request trustworthiness factor among multiple policies, and get the final trustworthiness factor to decide whether authorizing. In this model, authorization decision is given according to the calculation of request trustworthiness factor, which is more understandable, more suitable for real requirement and more powerful for security enhancement than traditional methods. Meanwhile the finer access control granularity is another advantage.