Yixin Jing

SPARQL graph pattern rewriting for OWL-DL inference queries

This paper focuses on the issue of OWL-DL ontology queries implemented in SPARQL. Currently, ontology repositories construct inference ontology models, and match SPARQL queries to the models, to derive inference results. Because an inference model uses much more storage space than the original model, and cannot be reused as inference requirements vary, this method is not suitable for large-scale deployment. To solve this problem, this paper proposes a novel method that passes rewritten SPARQL queries to the original ontology model, to retrieve inference results. We define OWL-DL inference rules and apply them to rewriting Graph Patterns in queries. The paper classifies the inference rules and discusses how these rules affect query rewriting. To illustrate the advantages of our proposal, we present a prototype system based on Jena, and address query optimization, to eliminate the disadvantages of augmented query sentences. We perform a set of query tests and compare the results with related works. The results show that the proposed method results in significantly improved query efficiency, without compromising completeness or soundness.

SPARQL Graph Pattern Rewriting for OWL-DL Inference Query

Graph pattern is the key body of a SPARQL query. Prevalent SPARQL query treatment delivers queries to OWL ontology model directly. To obtain inference results, the graph pattern are matched with inference ontology model which is generated by ontology inference engine. Since an inference model occupies much larger space than original model, and can not be reused as inference requirement varies, this method is not suitable to wide deployment in large scale. Alternatively, this paper proposes a novel method which sends rewritten graph patterns to original ontology model to acquire inference results. This method features in the reuse of original model between users, and avoidance of the heavy workload caused by generating and storing ontology inference model. The paper defines the ontology inference rules which affect the query resolving, and addresses a detailed process for rewriting graph pattern based on these rules. A prototype system is implemented to compare our proposal with current approaches. The experiment results show our methodpsilas advantages in aspects of completeness, soundness and effectiveness.

UbiMDR: Supporting Application-Independent Semantic Interoperability for Ubiquitous Applications

This paper proposes UbiMDR, a MDR (Metadata Registry)-based framework for supporting semantic consistency in ubiquitous computing environments. The chief objective of the UbiMDR is to let ubiquitous applications consistently and independently use information of sensors in a variety of sensor fields. Currently, applications depend on their sensor field. In other word, an application can utilize just information from a specific sensor field. To overcome this restriction, many issues from a hardware or software view must be resolved. This paper focuses on the consistent semantic management to provide the semantic interoperability between ubiquitous applications under ubiquitous environment consisting of various and different sensor fields. The UbiMDR provides infrastructure support for semantic consistency, sensor field-independent information utilization, and context-rich application development.

Speech Tagging Based Improvement of the RSS Polymerization News

Since a significant amount of redundant information causes problems like inefficiency or congestion in the existing RSS, a method using part of speech (pos) tagging to extract keywords is proposed to solve these problems. Firstly, the title of news is analyzed by using Chinese word segmentation and speech tagging system. Then, the keywords of the title are identified according to their part of speech. All of the extracted keywords are compared, categorized and stored according to the proposed criterion in this paper. In that case, all the news in the same category is identical or similar. Thus, redundant news can be hidden to users. According to the operation, statistics, comparison and analysis of system, and the

Access Control Model Based on RDB Security Policy for OWL Ontology

Most of information has been storing and managing in relational databases and there are many researches to store OWL ontologies. In this situation, a study on efficient access control model using relational security model is required. The paper proposes a novel access control model for OWL ontologies in relational database systems. The access control is realized through evaluating queries against an OWL data view. On one hand, the OWL data view prevents the sensitive information revealed to unauthorized users. On the other hand it considers the inference ability of users. An empirical study verifies the effectiveness of our approach.

QP-T: query pattern-based RDB-to-XML translation

This paper proposes a new query pattern-based relational schema-to-XML schema translation (QP-T) algorithm to resolve implicit referential integrity issue Various translation methods have been introduced on structural aspects and/or semantic aspects However, most of conventional methods consider only explicit referential integrities specified in relational schema It causes several problems such as incorrect transformation, abnormal relational model transition, and so on The QP-T algorithm analyzes query pattern and extract implicit referential integrities through equi-join between columns The QP-T algorithm is based on a concept that columns related to equi-join in relational schema can have referential integrity The most distinct contribution of QP-T algorithm is to enhance extraction of referential integrity relation information for translation Therefore, the QP-T algorithm reflects not only explicit referential integrities but also implicit referential integrities during RDB-to-XML translation The QP-T algorithm also prevents XML documents from incorrect conversion and increase translation accuracy.

A Universal Model for Policy-Based Access Control-enabled Ubiquitous Computing

The initial research of Task Computing in the ubiquitous computing (UbiComp) environment revealed the need for access control of services. Context-awareness of service requests in ubiquitous computing necessitates a well-designed model to enable effective and adaptive invocation. However, nowadays little work is being undertaken on service access control under the UbiComp environment, which makes the exposed service suffer from the problem of ill-use. One of the research focuses is how to handle the access to the resources over the network. Policy-Based Access Control is an access control method. It adopts a security policy to evaluate requests for resources but has a light-weight combination of the resources. Motivated by the problem above, we propose a universal model and an algorithm to enhance service access control in UbiComp. We detail the architecture of the model and present the access control implementation.ጊЀ㘷㠻Ԁ䭃䑎䴀

AN INFERENCE-ENABLED ACCESS CONTROL MODEL FOR RDF ONTOLOGY

Although RDF ontologies are expressed based on XML syntax, existing methods to protect XML documents are not suitable for securing RDF ontologies. The graph style and inference feature of RDF ontologies demands new methods for access control. Driven by this goal, this paper proposes a query-oriented model for RDF ontology access control. The model adopts the concept of ontology view to rewrite user queries. In our approach, ontology views define accessible ontology concepts and instances a user can visit, and enables a controlled inference capability for the user. The design of the views guarantees that the views are free of conflict. Based on that, the paper describes algorithms for rewriting queries according to different views, and provides a system architecture along with an implemented prototype. In the evaluation, the system exhibits a promising result in terms of effectiveness and soundness.

Implementation and quantitative evaluation of UbiMDR framework

This paper describes an implementation and quantitative evaluation of the UbiMDR framework. The UbiMDR framework has been proposed for consistent semantics management between ubiquitous applications. This framework enables an application field-independent information exchanging sharing and maxmize the usability of ubiquitous applications and data in devices (tags or smart cards). In the previous study, we just proposed the framework at the conceptual level including description of key components. In other words, the previous proposal has no implementation and evaluation. In this paper, we present a prototype implementation of the UbiMDR framework for semantic interoperability on the ubiquitous environment. To show the merits of the framework, we describe comparative evaluations between the conventional ubiquitous framework and the UbiMDR framework.

A rule-based publish-subscribe message routing system for ubiquitous computing

The ubiquitous computing produces big volume of messages as the pervasive computability is deployed in large scale. As a middleware between the message producer and message consumer, message routing system enables backend systems to efficiently acquire the interested message. A widely adopted message routing mechanism is the content-based publish-subscribe framework. Based on this paradigm, we propose a rule-based system for supporting message routing in ubiquitous computing. The novel system features in the flexibility of the message computing, which is accomplished through a set of message operators. The message consumer could select the appropriate operator and specify the operating rule to get satisfying messages.