In this paper, we propose a non-blocking buffer management scheme based on a lock-free variant of the GCLOCK page replacement algorithm. Concurrent access to the buffer management module is a major factor that prevents database scalability to processors. Therefore, we propose a non-blocking scheme for bufferfix operations that fix buffer frames for requested pages without locks by combining Nb-GCLOCK and a non-blocking hash table. Our experimental results revealed that our scheme can obtain nearly linear scalability to processors up to 64 processors, although the existing locking-based schemes do not scale beyond 16 processors.

We propose an efficient distributed query processing method for large XML data by partitioning and distributing XML data to multiple computation nodes. There are several steps involved in this method; however, we focused particularly on XML data partitioning and dynamic relocation of partitioned XML data in our research. Since the efficiency of query processing depends on both XML data size and its structure, these factors should be considered when XML data is partitioned. Each partitioned XML data is distributed to computation nodes so that the CPU load can be balanced. In addition, it is important to take account of the query workload among each of the computation nodes because it is closely related to the query processing cost in distributed environments. In case of load skew among computation nodes, partitioned XML data should be relocated to balance the CPU load. Thus, we implemented an algorithm for relocating partitioned XML data based on the CPU load of query processing. From our experiments, we found that there is a performance advantage in our approach for executing distributed query processing of large XML data.

The purpose of this study is to propose Context-Aware Support Vector Machine (C-SVM) for application in a context-dependent recommendation system. It is important to consider users’ contexts in information recommendation as users’ preference change with context. However, currently there are few methods which take into account users’ contexts (e.g. time, place, the situation and so on). Thus, we extend the functionality of a Support Vector Machines (SVM), a popular classifier method used between two classes, by adding axes of context to the feature space in order to consider the users’ context. We then applied the Context-Aware SVM (C-SVM) and the Collaborative Filtering System with Context-Aware SVM (C-SVM-CF) to a recommendation system for restaurants and then examined the effectiveness of each approach.

Update management of XML documents is an increasingly important research issue in XML databases, because contents of XML documents evolve as time goes by. Even though, XML databases should be able to effectively process XML queries as well as updates on the documents. We propose a robust node-numbering scheme for XML documents named QRS (quartering-regions scheme). In QRS, reefs (regions expressed by floating-point numbers), a variant of regions, are used for expressing node-numbers. Reefs are almost compatible to regions, and thus they can be used for detecting ancestor-descendant relationship among nodes for the purpose of efficient query processing. Moreover, reefs can cope with updates by utilizing gaps between reefs in terms of floating-point numbers. Consequently, we can avoid node renumbering as much as possible.

This paper presents an approach to bilingual lexicon extraction from comparable corpora and evaluations on Cross-Language Information Retrieval. We explore a bi-directional extraction of bilingual terminology primarily from comparable corpora. A combined statistics-based and linguistics-based model to select best translation candidates to phrasal translation is proposed. Evaluations using a large test collection for Japanese-English revealed the proposed combination of bi-directional comparable corpora, bilingual dictionaries and transliteration, augmented with linguistics-based pruning to be highly effective in Cross-Language Information Retrieval.

Abstract Summary: We have developed a system for visualizing the Gene Ontology™ hierarchy. The graphical browser interactively displays diagrams of the inheritance relationship for each term to help understand the meanings of terms when handling gene annotation data. Availability: The GeneAround GO viewer is open to the public at http://db.aist-nara.ac.jp/genearound/ Contact: [email protected] * To whom correspondence should be addressed at Information Technology Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, JAPAN.

In this paper, we propose a retrieval method for multimedia documents. In our method, features of each medium such as text, image, and their layout information are extracted from documents. For a given query, similarity values are calculated for each media, then those values are integrated into one similarity value per document. We propose four methods for calculating the integrated similarity values. Also, we performed experiments using PDF files, and verified the effectiveness of our method.

For most of the index structures for XML data proposed so far, updating is a problem, because an XML element's coordinates are expressed using absolute values. Due to the structural relationship among the elements in XML documents, we have to re-compute these absolute values if the content of the source data is updated. The reconstruction requires the updating of a large portion of the index files, which causes a serious problem, especially when the XML data content is updated frequently. In this paper, we propose an indexing structure scheme based on the relative region coordinates that can effectively deal with the update problem. The main idea is that we express the coordinates of an XML element based on the region of its parent element. We present an algorithm to construct a tree-structured index in which related coordinates are stored together. In consequence, our indexing scheme requires the updating of only a small portion of the index file.

This article describes XRel, a novel approach for storage and retrieval of XML documents using relational databases. In this approach, an XML document is decomposed into nodes on the basis of its tree structure and stored in relational tables according to the node type, with path information from the root to each node. XRel enables us to store XML documents using a fixed relational schema without any information about DTDs and also to utilize indices such as the B + -tree and the R -tree supported by database management systems. Thus, XRel does not need any extension of relational databases for storing XML documents. For processing XML queries, we present an algorithm for translating a core subset of XPath expressions into SQL queries. Finally, we demonstrate the effectiveness of this approach through several experiments using actual XML documents.

This paper describes COBOL Script, a Web-oriented script language developed by Hitachi. COBOL Script includes the following features: (1) The language specifications, which consist of functions required for Web computing, are a subset of COBOL85, the most frequently used programming language in business information systems. (2) COBOL Script supports decimal arithmetic functions that have the same precision as in standard COBOL85 on mainframe computers. (3) Efficient implementation was based on analysis of the pros and cons of the COBOL processing system. Using COBOL Script, users can: (1) Process applications requiring high precision, such as account-related applications, over the Web. (2) Use a test debugger and a Coverage Function with COBOL Script for large-scale development projects. (3) Use Japanese in programs. (4) Achieve good run-time performance.

The authors describe a method for supporting the process of accumulating personal everyday memory and sharing it in a community. Two ideas are used to implement the method. The first idea is intimate computing which enables people to externalize and accumulate personal memory using associative representation at any time and any place. The second idea is a talking virtualized egos metaphor that visualizes community knowledge interaction. This helps community members to find out common interests and shared knowledge. Based on these ideas, we developed the system called CoMeMo which helps people to manage personal and community memory. In experimentation, we observed the following: (a) collaborative knowledge building, (b) change of shared information, (c) creation of new human relationships.