Daxin Liu

Using ontologies for semantic query optimization of XML database

As XML has gained prevalence in recent years, the management of XML compliant structured-document database has become a very interesting and compelling research area. Effective query optimization is crucial to obtaining good performance from an XML database given a declarative query specification because of the much enlarged optimization space. Query rewriting techniques based on semantic knowledge have been used in database management systems, namely for query optimization. The main goal of query optimization is to rewrite a user query into another one that uses less time and/or less resources during the execution. When using those query optimization strategies the transformed queries are equivalent to the submitted ones. This paper presents a new approach of query optimization using ontology semantics for query processing within XML database. In fact, our approach shows how ontologies can effectively be exploited to rewrite a user query into another one such that the new query provides equally meaningful results that satisfy the intention of the user. Based on practical examples and their usefulness we develop a set of rewriting rules. In addition, we prove that the results of the query rewriting are semantically correct by using a logical model.

A new automatic intrusion response taxonomy and its application

The response taxonomy is a key to realizing automatic an intrusion response system as it provides theoretical framework for responding coherently to attacks. This paper presents a new taxonomy called 5W2H on the basis of analyzing the taxonomies, and the application prototype running over IBM Aglet is given.

Clustering large scale of XML documents

Clustering is able to facilitate Information Retrieval. This paper addresses the issue of clustering a large number of XML documents. We propose ICX algorithm with a novel similarity metric based on quantitative path. In our approach, each document is firstly represented by path sequences extracted from XML trees. Then these sequences are mapped into quantitative path, by which the distance between documents can be computed with low complexity. Finally, the desired clusters are constructed by utilizing ICX method with literal local search. Experimental results, based on XML documents obtained from DBLP, show the effectiveness and good performance of the proposed techniques.

Dissymmetrical Wireless Sensor Network Internet Access Technology Based on Optimum Gateway

Along with the establishment of the absolute dominant position of Internet as the backbone network of worldwide wire network, the interconnection between wireless sensor network and Internet will have larger development space and can be more widely used. A kind of dissymmetrical Internet access technology-based on optimum gateway is proposed in this paper, by reactive style gateway discovery method to equip sensor nodes with global routing IP addresses to realize the data communication between nodes within network and main frames on the Internet.

Design and implementation of a workflow-based message-oriented middleware

The rapid growth of data exchange on the networks has brought on many critical problems that require an answer. Generally, Internet data exchange systems are based on traditional client/server architecture, which models are less scalable and bring on especially high maintenance cost in the data ex-change domain. For these reasons, we present a workflow-based message-oriented middleware (WMOM) system model for asynchronous communication platforms. The model combines workflow mechanism and message-oriented middleware. It not only makes applications to be isolated from communication network, but also improve the flexibility and scalability.

XML document clustering by independent component analysis

When XML documents are clustered, the high dimensionality problem will occur. Independent Component Analysis (ICA) can reduce dimensionality and in the meanwhile find the underlying latent variables of XML structures to improve the quality of the clustering. This paper proposes a novel strategy to cluster XML documents based on ICA. According to D_path extracted from XML trees, the document was at first represented as Vector Space Model (VSM).Then ICA is applied to reduce the dimensionality of document vectors. Furthermore, document vectors are clustered on this reduced Euclidean Space spanned by the independent components. The experiments show that ICA can enhance the accuracy of the clustering with stable performance.

An Efficient Power and Coverage Algorithm in WSNs

An efficient power and coverage algorithm called EPCA is proposed that puts redundant sensor nodes to sleep mode to save energy while maintain the sensing field covered. EPCA includes three algorithms: the node checking algorithm, the blind point avoidance algorithm and the sleeping nodes turning on algorithm. Detailed simulation results and compared to existed schemes prove the proposed EPCA algorithm not only guarantees the network is fully covered at least k level of coverage, but also prolongs network lifetime.

Research of Metadata Extracting Algorithm for Components from XML-Based in the Semantic Web

In this paper a novel algorithm to metadata extracting for components from XML-based based on rules in the semantic Web is proposed. This algorithm is based on the challenges facing institutions managing ever-increasing numbers of components over the long term. We consider the current environments and challenges for managing preservation components in the semantic Web. The Dublin core-based metadata is used to manage components in the semantic Web. Design of rule library is discussed after introducing syntax and semantics of the rules. The system named SCDB (software component database) is developed. The system is based on the algorithm aforementioned. The system can perform automatic Dublin core-based metadata extracting algorithm from components which is described by XML documents. The Dublin Core- based metadata extracting algorithm for components based on rules is described in this paper. The future works are discussed in the end.

A holistic approach to survivable distributed information system for critical applications

In this paper, a holistic approach to realize survivability of distributed information network systems for critical applications(DISCA) based on three basic states, processed, stored, and transmitted, of information (called a PST-based system model), is proposed and its evaluation method and some experiment results are given as an example of its application. A PST-based system model brings all three parts together and coordinates them through the services supported by them, in which whole system’s survivability is embodied by system services and their interdependency relations. With this model, a multi-layer survivability framework based on the information states is formed and the complexity of a DISCA system in implementation and evaluation can be conquered in the most prevalent approach—“divide and conquer” approach.

ORM-ODM: Ontology Definition Metamodel for Object Role Modeling

In order to share, exchange, and process ontologies and business rules modeling by Object-Role Modeling (ORM) on Internet and the open connectivity environments, it is necessary to develop a standard ORM meta-model by ontology meta-modeling method based on MOF 2.0. A MOF-compliant ontology definition meta-model for ORM 2.0 (ORM-ODM) was proposed and validated by MOF-supported tools.