Chuanshan Gao

Add Semantic Role to Dependency Structure Language Model for Topic Detection and Tracking

In this paper, an idea of adding semantic role to the dependency structure language model is proposed. Firstly, the dependency structure language model for topic detection and tracking is presented. Then we introduce the method to determine the semantic role for the constituents of a sentence. Finally, we add the semantic role to the dependency structure language model Compare the verbs of the sentences in the stories with a list of verbs related with the verb of the topic. Then, annotate the verbs with semantic roles. This can enable us establish a relation between topics and semantic roles. So, only stories whose sentences containing the right semantic roles are selected. We propose using this semantic information as an extension of the dependency structure language model in order to reduce the number of stories retrieved by the system, and get a high precision in topic detection and tracking.

Reputation-based Trust in Wireless Sensor Networks

Wireless sensor networks (WSNs) are becoming more and more common. WSNs have many existing and envisioned applications due to their ease of deployment, particularly in remote areas. But the security of WSNs is still an issue. Some existing approaches mainly rely on cryptography to ensure data authentication and integrity. These approaches only address part of the problem of security in WSNs. However, these approaches are not sufficient for the unique characteristics and novel misbehaviors encountered in WSNs. Recently, the use of reputation systems has become an important mechanism in WSNs. In this paper we propose a reputation-based trust which borrows tools from probability, statistics and mathematics analysis. We have suggested a new term certainty used in trust system and we argued that the positive or negative outcomes for a certain event is not enough information to make a decision in WSNs. We build up a reputation space and trust space in WSNs, and define a transformation from reputation space to trust space. Finally, we discuss some important properties of them and point out some open problems in reputation system in WSNs.

Agent-Based Trust Management Model for Wireless Sensor Networks

In wireless sensor networks (WSNs), these sensor nodes cooperate with each other to form a network without using any infrastructure. WSNs has a wide application. But the security of WSNs is still an issue. Traditionally cryptographic mechanisms such as authentication and encryption only address part of the problem of security in WSNs. Recently, the use of reputation and trust systems has become an important mechanism in WSNs. In this paper, we develop a distributed agent-based trust management scheme. The agent node use watchdog mechanism to observe the behavior of the sensor nodes and computes the trust rating for them. We consider packet-dropping and hello flood attack in our simulation, the simulation results and analysis show that our scheme can fast detect the malicious nodes and scale well for wireless sensor networks.

Lightweight anomaly intrusion detection in wireless sensor networks

Wireless Sensor Networks (WSNs) have an excellent application to monitor environments such as military surveillance and forest fire. However, WSNs are of interest to adversaries in many scenarios. They are susceptible to some types of attacks because they are deployed in open and unprotected environments. The WSNs are constituted of scarce resource devices. These security mechanisms which used for wired networks cannot be transferred directly to wireless sensor networks. In this paper we propose lightweight anomaly intrusions detection. In the scheme, we investigate different key features for WSNs and define some rules to building an efficient, accurate and effective Intrusion Detection Systems (IDSs). We also propose a moving window function method to gather the current activity data. The scheme fits the demands and restrictions of WSNs. The scheme does not need any cooperation among monitor nodes. Simulation results show that we proposed IDSs is efficient and accurate in detecting different kinds of attacks.

Event-based Trust Framework Model in Wireless Sensor Networks

The security of wireless sensor networks is ever more important nowadays. Most of the proposed security protocols in wireless sensor networks are based on authentication and encryption. But all of them only address part of the problem of security in wireless sensor networks. Recently, the use of reputation and trust systems has become an important secure mechanism in wireless sensor networks. In this paper we propose a new protocol ETSN to construct a trust framework model in wireless sensor networks. The ETSN will be more suitable than ATSN and RFSN in wireless sensor networks. The simulation results and analysis show that our scheme not only can fast detect the malicious nodes and scale well for wireless sensor networks, but also can distinguish trust rating with different event.

A Trust Management Model for P2P File Sharing System

Peer-to-peer (P2P) network systems have an open and dynamic nature for sharing files and real-time data transmission. While P2P systems have already many existing and envisioned applications, the security issue of P2P systems is still worth deeply researching. Some traditional approaches mainly rely on cryptography to ensure data authentication and integrity. These approaches, however, only addressed part of the security issues in P2P systems. In this paper, we propose a trust management model for P2P file-sharing systems. We use the incomplete experience to get the trust rating in P2P systems, and use aggregation mechanism to indirectly combine and obtain other nodes trust rating. Simulation results and analysis show that our proposed trust management model can quickly detect the misbehavior peers and limit the impacts of them in a P2P file-sharing system.

Trust Propagation and Aggregation in Wireless Sensor Networks

In a multi-hop wireless sensor networks (WSNs), these sensor nodes cooperate each other to form a network without using any infrastructure, which has a wide application due to their easy of deployment. But the security of WSNs is still an issue. Traditionally cryptographic mechanisms such as authentication and encryption only address part of the problem of security in WSNs. Recently, the use of reputation systems has become an important mechanism in WSNs. The trust management is still a very important problem for reputation systems in WSNs. In this paper we develop a formal treatment of trust management for WSNs. The main contribution of our paper is that we define two kinds of operators, propagation and aggregation. It can combine and diffuse trust rating of nodes in WSNs. Simulation results and analysis show that our proposed operators can detect the misbehavior sensor fast and limited the effect of malicious report the trust rating.

On Improving the Precision of Localization with Gross Error Removal

Location information is always useful in wireless sensor networks (WSN). The precision of localization is crucial for some specific applications. Methods for node localization in WSN usually rely on the measurements of received strength or time-of-flight of an incoming signal. The quality of these measurements always has great influence on the precision of localization. In this paper, special emphasis is put on the error analysis for distance measurement between WSN nodes. Error is broken down into three parts, namely, systematic error, random error, and gross error. Gross error is highlighted and methods for removing gross error are discussed. Dixon test is recommended for gross error removal in data preprocessing phase before localization computation in WSN.

A new kind of session keys based on message scheme for sensor networks

In order to achieve security in wireless sensor networks (WSN), it is important to encrypt message, but these sensor node resource constraints, key management in WSN, recently, usually uses some key pre-distributed scheme or session key scheme to achieve security. In this paper, we propose a new rekeying management for group sensor nodes, which is based on message between group neighbor nodes. Our scheme exhibits a nice power efficient and excellent updating communications keys in terms of energy efficient, communication cost, security, and computational overhead.

Wireless Grid Computing over Mobile Ad-Hoc Networks with Mobile Agent

Mobile ad-hoc network (MANET) opens a novel area for grid computing to extend pervasive computation in wireless environment. In this paper, a mobile agent based approach is proposed for building computation grid over MANET that is characterized as self-organizing and without fixed infrastructure. It distributes computations and aggregate resources through mobile agent. As an autonomous entity, it visits nodes with sufficient battery power and resource capability, and negotiates their resource provision for running the computation job. It solves the problem of network topology change due to node mobility or power consumption, which may affect the stability of grid. Also it introduces flexibility in handling different cooperation models of nodes for resource sharing, thus is able to collect a lot of nodes in MANET to participate in grid computing.