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Ray tracing requires many ray-obect intersection tests. A way of reducing the number of ray-object intersection tests is to subdivide the space occupied by objects into many nonoverlapping subregions, called voxels, and to construct an octree for the subdivided space. In this paper, we propose the Octree-R, an octree-variant data structure for efficient ray(More)
We propose query optimization techniques that fully utilize the advantages ojpath indexes in object-oriented database systems. Although path indexes provide an eficient access to complex objects, little research has been done on query optimization that fully utilize path indexes. We first devise a generalized index intersection technique, adapted to the(More)
The intermediate result cardinality the number of objects satisfying a condition given in a query is an important factor for estimating the cost of the query in query optimization In this paper we show that an object oriented query often involves partial participation of classes in a relationship We then present a new technique for estimating the(More)
Join is an operation that is frequently used and the most expensive in processing database queries. In this paper we propose a new efficient join algorithm(called the MLGFJoin) for relations indexed by the tnul~ilevrl grirlfile(MLGF), a multidimensional dynamic hashed file organization. The MLGF-Join uses the domain space partition maintained in the(More)
Due to rapid improvement of information technology, the emergence of various information channels such as mobile devices and social media has been producing tremendous amount of data. The evolution of smartphones and social network services (SNS) leads to the big data era. The research for unstructured, large and varied data, has been going on for more(More)
| The intermediate result cardinality { the number of objects satisfying a condition given in a query { is an important factor for estimating the cost of the query in query optimization. In this paper we show that an object-oriented query often involves partial participation of classes in a relationship. We then present a new technique for estimating the(More)
SUMMARY WEbcoli is a WEb application for in silico designing, analyzing and engineering Escherichia coli metabolism. It is devised and implemented using advanced web technologies, thereby leading to enhanced usability and dynamic web accessibility. As a main feature, the WEbcoli system provides a user-friendly rich web interface, allowing users to virtually(More)
Although various types of path indexes – indexes on path expressions – have been proposed for efficient processing of object-oriented queries, conventional join algorithms do not effectively utilize them. We propose a new join algorithm called OID join algorithm that effectively utilizes (multiple) path indexes in object-oriented databases. When (multiple)(More)
With rapid development of information and communication technology, people are very diverse in education, learning style, and knowledge improvement methods. This paper presents an approach of converting documents into knowledge of Chatbot system that enables users to make more benefits of it by asking and answering questions through the use of electronic(More)