Showing papers by "Shojiro Nishio published in 1999"

Advanced Multimedia Content Processing

Abstract: Summarization of video data is of growing practical importance because the more expanding video databases, inundate users with vast amounts of video data, the more users need reduced versions which they can assimilate with limited effort in shorter browsing time. In recent days, many researchers have investigated summarizing techniques, such as fast-forward play back, and skipping video frames at fixed intervals of time. However, all these techniques are based on syntactic aspects of the video. Another idea is to present summarized videos according its semantic representation. The critical aspect of compacting a video is context understanding, which is the key to choosing “significant scenes” that should be included in the summarized video. The goal of this work is to show the utility of semantic representation method for video summarization. We propose a method to extract significant scenes and create a summarized video without losing the content of the video’s story. The story is analyzed by its semantic content and is represented in a structured graph where each scene is represented by affect units.

A user customized selection and categorization for broadcast data

Abstract: Recently, many broadcast satellites have been launched to provide data broadcasting services for public users. Although the provided services can cover many kinds of data and a wide range of user interest, it is considered that, in general, a user is interested in only some specific genres of data. Consequently, storing all received data is considered to be inefficient and only wasting a large amount of memory. This motivated us to introduce an information filtering system into a broadcast data receiving system. The use of filtering system increases the efficiency of memory usage and reduces time for searching interesting data. In this paper, we propose a filtering method that uses a tree structure to represent user preferences. The use of this filtering method enable the receiving system to select only data that match user's interest and classify the stored data in the way that suits the user's access pattern. We also describe the design and implementation of our broadcast data. Receiving system that makes use of the proposed filtering method. Further, we evaluate the performance of our method by showing some simulation results.

A WWW server with media scaling mechanism based on page transmission latency

Abstract: Today, billions of users use the Internet to access multimedia information on the World Wide Web (WWW). Most users, however, are given low-speed connection to the Internet and are often irritated by the long transmission time of WWW pages. Therefore, it is very important for information providers to tailor the presentation of information to a user's network environment. In this paper, we propose an architecture for a WWW server with a media scaling mechanism. The WWW server can control the transmission time of WWW pages based on the transmission time threshold specified by the information providers. We also describe our implementation of the WWW server and discuss some experimental results.

A Scheduling Method of Database Migration for WAN Environments.

Abstract: In broadband networks, appropriate use of database migration can drastically shorten the average transaction processing time of a distributed database system. In previous work, we have proposed a transaction processing method based on database migration, a method in which we assumed that the network bandwidth is very broad and almost uniform over the whole network. However, WANs consist of various types of networks, including private LANs, narrowband public networks and broadband backbones; thus, it is di cult to control database migration in the granularity of the transaction and to execute database migration through networks other than backbones. Therefore, that method cannot be applied directly in WAN environments. In this paper, we propose a database migration scheduling method which is suitable for use in such heterogeneous WANs. We also discuss one method of implementation our proposed scheduling method in a practical environment. keywords: database migration, WAN (Wide Area Network), broadband network, distributed database

MASEMS: a scalable and extensible multimedia server

Abstract: Advances in network, hardware, and software technologies have brought multimedia services over the Internet into reality. However, as the Internet community is growing so fast, server scalability becomes a critical issue. For the customers on the other hand, administrative costs and complexity are still the number one problems to face. We propose a multimedia server that will liberate customers from messy configuration problems while scaling up the server can be achieved just by adding new server nodes and the software infrastructure. We present our solutions from the view of software architecture and how our proposed system solves some critical issues that could not be solved by the existing systems.

Fast methods with magic sampling for knowledge discovery in deductive databases with large deduction results

Abstract: The ability of the deductive database to handle recursive queries is one of its most useful features. It opens up new possibilities for users to view and analyze data. This ability to handle recursive queries, however, still cannot be fully utilized because when recursive rules are involved, the amount of deduced facts can become very large, making it difficult and sometimes impossible to store, view or analyze the query results. In order to overcome this problem, we have proposed the DSK method and the DSK(S) method to discover characteristic rules from large amount of deduction results without having to store all of them. In this paper, we propose two new methods, the DSK(T) method and the D-SK(ST) method which are faster than the DSK method and the DSK(S) method respectively. In addition, we propose a new sampling method called magic sampling, which is used by the two methods to achieve the improvement in speed. Magic sampling works when linear recursive rules are involved and the magic set algorithm is used for deduction.

On Relocation Decision Policies of Mobile Databases

Abstract: Recently, mobile computing has received much attention from database community. Sharing information among mobile users is one of the most challenging issues in mobile computing due to user mobility. Replication is a promising technique to this issue. However, adopting replication into mobile computing is a non-trivial task, since we are still facing other problems such as the lack in disk capacity and wireless network bandwidth used by mobile users. We have proposed a dynamic replica allocation strategy called User Majority Replica Allocation (UMRA) that is well suited to the modern architecture of mobile computing environment while avoiding such problems mentioned above. In this paper, we propose two relocation decision policies for UMRA and we provide a cost analysis for them. We also provide a cost analysis for another replica allocation strategy called Static Replica Allocation (SRA) for a comparison purpose. key words: mobile Computing, databases, replication, evaluation

Performance evaluation of two step locking protocol for location databases in mobile environment

Abstract: The mobile computing paradigm introduces new technical issues in the area of database systems. In a mobile environment, the location of mobile users is a kind of system data that is referred most frequently. In mobile environments, location data are stored in databases. However, as the location of user is a frequently changing piece of data, queries on location data are prone to inconsistency. Aggregate queries are among the type of queries that will suffer greatly. In this paper, we propose the two-step locking protocol for location databases that can guarantee aggregate queries to get consistent results. We show that our proposed protocol performs much better than the conventional single-step locking protocol if used for location databases in mobile environment.