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With active research on Web ontology, various storages and ontology query languages have been introduced. The most representative query language for Web ontology is SPARQL which have been developed by W3C, and most storages are based on relational database. Under such a situation, the necessity of SPARQL-to-SQL translation algorithm development becomes(More)
CDN does not calculate connections between infra networks and user networks by increasing physical network. Instead, CDN decentralizes bottlenecked data traffics or contents to main parts of Internet network. By this, an amount of traffics passing through middle-mile of complicated Internet is decreased and CP (contents provider)'s server loads are reduced(More)
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(More)
This paper proposes an enhanced storage model as a plug-in of Jena for semantic grid computing. Semantic grid is built using the technologies of the semantic Web. Jena is one of the most representative frameworks for building semantic Web applications. Jena can be used for building the semantic grid and its applications. It provides a programmatic(More)
In this paper, we take a rather different approach. We explore how to support security models for XML documents by leveraging on techniques developed for relational databases. More specifically, in our approach, (1) Users make XML queries against the given XML view/schema, (2) Access controls for XML data are specified in the relational database (3) Data(More)
The existing risk propagation models are limited and inadequate in analyzing cyber attacks caused by various threats in information systems, because it has focus on only a specific threat such as a virus or a worm. Therefore, risk propagation model based on the Markov process is proposed, which can be applied to diverse threats in information systems. The(More)
This paper performs cost evaluation of storage-independent SPARQL-to-SQL use model. With development of semantic Web, much research focuses on various technologies about Web ontology. Especially, for management and searching of data in Web ontology, various storages based on RDB and query languages (e.g., SPARQL, RDQL, RQL) have been developed with(More)
Sensors in ubiquitous computing provide a new opportunity to extend existing RFID capabilities to situation-awareness. This paper proposes several alternatives of the situation-aware radio frequency identification (SA-RFID) system architecture and analyzes the pros and cons of each alternative.
This paper presents an efficient integration method on metadata of Web resources for realizing the semantic Web. Since the semantic Web must accept and understand all Web information resources that are represented with the other methods, an integration of the metadata has become an issue. Our method treats two representative standardized ontology schemes,(More)
Although Jabber started from the instance messaging protocol, it became one of the most important toolkits for developing distributed applications. The existing Jabber authentication model doesn't support a mechanism to enable a client to access the servers in another domain directly. This limitation causes data duplication and synchronization problems in(More)