Li Renfa

An Intrusion Alarming System Based on Self-Similarity of Network Traffic

Intrusion detection system can make effective alarm for illegality of network users, which is absolutely necessarily and important to build security environment of communication base service. According to the principle that the number of network traffic can affect the degree of self-similar traffic, the paper investigates the variety of self-similarity resulted from unconventional network traffic. A network traffic model based on normal behaviors of user is proposed and the Hurst parameter of this model can be calculated. By comparing the Hurst parameter of normal traffic and the self-similar parameter, we can judge whether the network is normal or not and alarm in time.

The research of the data security for cloud disk based on the Hadoop framework

In order to solve the existing security problem of the distributed network cloud disk, such as transmission, storage security problems, etc, a network cloud disk safety storage scheme based on Hadoop is proposed. Based on the different confidential level of user data, it gives selective encryption scheme, which gives full consideration to the following security issues, such as the security of the user data transmission in the network, user data no verification , the user data privacy might be leaked, etc. Combined with the rapid encryption of symmetric encryption algorithm and identity authentication of RSA , overtime checking and the performance of Hadoop , the distributed network cloud data security storage disk can supply secured, effective, stable effect. Finally the security of the scheme is proved by BANLOGIC.

An Energy-Aware Distributed Clustering Algorithm in Wireless Sensor Networks

We proposed a distributed energy saving clustering algorithm BPEC. Cluster-heads are elected by two probabilities. The primary probability is based on the ratio between average residual energy of neighbor nodes and itself residual energy. The subsidiary probability is the nodes degree. By using BPEC algorithm, the entire network broadcasting complexity is O (n), the entire network computing complexity is O (1). The cluster set generated by BPEC is proved to be a Maximum Independent Set. The experimental results show that when nodes is enough, the cluster set size is close to the theoretical values.We proposed a distributed energy saving clustering algorithm BPEC. Cluster-heads are elected by two probabilities. The primary probability is based on the ratio between average residual energy of neighbor nodes and itself residual energy. The subsidiary probability is the nodes degree. By using BPEC algorithm, the entire network broadcasting complexity is O (n), the entire network computing complexity is O (1). The cluster set generated by BPEC is proved to be a Maximum Independent Set. The experimental results show that when nodes is enough, the cluster set size is close to the theoretical values.

Evaluating and Improving Wireless Local Area Networks performance

A Wireless Local Area Network (WLAN) is a type of Local Area Network (LAN) that uses high frequency radio waves rather than wires to communicate and transmit data [1]. It is a flexible data communication system implemented as an extension to or as an alternative for, a wired LAN. It provides large companies the option to connect the current wired networks to the wireless network without any problems and gives user the option to use any kind of applications regardless of its source or vendors [2]. As data sharing is sometimes slow or worst slowness due to the performance of the WLAN which is a key factor in spreading and usage of such technologies. Hence it is necessary to identify the quality of the wireless connection and how to improve the communication through the WLAN. Therefore, in this paper, Evaluating and Improving Wireless LANs Performance has been proposed to address mains parameters as Wireless LAN performance indicators and then to propose some methods to improve the performance of WLAN connection via OPNET Modeler 9.1., an advanced network simulator.

SASO: Security Adaptive Self-Organization for Wireless Sensor Networks

Secure communication is very important in computer networks and authentication is one of the most eminent preconditions. This paper proposes Session-key derivation, decentralize key management for wireless sensor networks covering the aspects of key deployment, key refreshment, and key establishment to achieve a high-level security for WSNs.

100GBaud optical transceiver: An optical time division multiplexing solution

An on-chip optical time division multiplexing (OTDM) transceiver for 100GBaud transmission system is proposed based on based on 4 bit 25Gbps bit-streams at the electrical interface. The crosstalk extinction ratio at the worst sub-channel is 1.9dB with 10dB depth modulator, and the insertion loss caused by the OTDM mechanism is about 10dB.

Porting TOPPERS/ASP to the Heterogeneous Multi-core Architecture

Real-time operating system (RTOS) as well as simplify the process of the design of embedded software, heterogeneous multi-core architecture becomes its an important research and application areas. TOPPERS/ASP is an open source implementation for micro ITRON 4. 0. Our study focus on the porting of TOPPERS/ASP to the omap3530 processor, which have an arm and dsp processor. The inter-processor communication (IPC) mechanism is also described.this kernels accuracy of the port kernel is proved.

The Analysis of Priority-Based Slotted CSMA/CA Algorithm in IEEE 802.15.4 Sensor Network

IEEE 802.15.4 standard provides a MAC and PHY layer specification for a low rate, low power, low complexity and short range Wireless Personal Area Network (WPAN). The basic access mechanism used by the standard is the CSMA/CA. In this paper, Markov chain model is used to reflect the characteristics of the IEEE 802.15.4 medium-access control protocol, and proposed an enhanced priority-based slotted CSMA/CA algorithm. The simulation results used OMNET environment show that proposed algorithm can achieve higher channel access rate.

Embedded real-time system modeling language analysis and comparison

Auto cruise control system (CCS) is a typical case of embedded real-time systems (RTES). Model-based design method describes both system software and hardware structure by the effective modeling language in RTES. That satisfies RTES real-time capability and reliability, and enhances productivity and saves cost expenses. This paper models CCS using the modeling languages UML (Unified Modeling Language) and AADL (Architecture Analysis and Design Language) respectively, and analyzes the characteristics of the two languages, then discusses RTES modeling development trend.

NHDCOM: Node heterogeneous degree-based consistency maintenance method for unstructured P2P systems

Replica strong consistency is the basis of developing newly-developed P2P applications. This paper analyses current replica consistency maintenance algorithms, proposes a novel replica consistency maintenance algorithm - node heterogeneous degree-based consistency maintenance algorithm (NHDCOM) according to the characteristic of unstructured P2P system. NHDCOM denotes the replica node capability by node heterogeneous degree, NHD. It manages replica nodes using Chord protocol and collects their NHD along with a Replica Information-gathering Tree built through the finger table-based ring partition method. Moreover, a replica update problem model is abstracted in NHDCOM. And then a Minimum Delay Content Update Tree algorithm based on dynamic programming method is proposed to improve the update speed. Simulation results demonstrate that this method is more efficient in maintaining strong replica consistency for unstructured P2P systems.