Studies on Multimedia Information Systems in Broadband Networks

本研究在宽带网络多媒体信息系统的设计和实现技术方面取得了以下研究成果：1.为了开发一个多媒体信息存储和管理平台，我们利用一个商用的面向对象的数据库管理系统，设计并实现了一个ASN.1(Abstract SynTax Notation One)数据库系统。通过一个典型的ASN.1数据库应用程序的开发和应用系统的评估，我们证明了我们可以很容易地在我们的平台系统上开发实际的ASN.1数据库应用程序。2.作为宽带网络中的一种新的数据库技术，我们研究了基于数据库迁移的事务处理方法。特别提出了一种考虑数据库迁移的并发控制方法和几种位置管理方法，并通过仿真实验对其进行了评估。对于基于宽带网络的多媒体演示系统，我们考虑了将实时视频融合到3D计算机图形中的虚拟空间，并讨论了实现多媒体演示系统的服务质量(Quality Of Service)和细节层次(Lod)这两个重要方面。4.对于多媒体信息系统的人机界面，我们考虑了虚拟空间电话会议系统。重点研究了宽带网络下人体动作的再现，提出了几种实现人体动作、面部表情和手势实时三维再现的方法，为宽带网络多媒体信息系统的构建奠定了新的基础技术。

In this study, we obtained the following research results regarding the design and implementation techniques of multimedia information systems in broadband networks :1.For developing a platform to store and manage multimedia information, we have designed and implemented an ASN.1 (Abstract Syntax Notation One) database system using a commercially available object-oriented database management system. Through the development of a typical ASN.1 database application and the evaluation of the application system, we have demonstrated that we can easily develop practical ASN.1 database applications on our platform system.2.As a new database technique in broadband networks, we have investigated transaction processing methods based on the database migration. Especially, we proposed a concurrency control method and several location management methods considering migration of database, and then evaluated them by simulation experiments. As a result, we showed that our proposed methods can achieve higher throughput than the conventional transaction processing methods.3.Regarding multimedia presentation systems using broadband networks, we considered a virtual space incorporating live video into a 3D computer graphics, and then discussed the QoS (Quality of Service) and the LoD (Level of Detail) which are the important aspects for implementing multimedia presentation systems.4.As for man-machine interface of multimedia information systems, we have considered virtual space teleconferencing systems. Especially, we investigated the reproduction of human body movements via broadband networks, and we proposed several methods realizing real-time 3D reproduction of human's movement, facial expressions, and hand gestures.Based on these research results, we have established the new fundamental techniques for constructing multimedia information system in broadband networks.