The design and implementation of a novel English writing environment is described. The system integrates modern computer and networking technologies with analytical tools from linguistics and language pedagogy to construct an advanced English writing environment. The system is not only suitable for students in learning English, but also of benefit to teachers in making comments and detecting learners' common difficulties. Furthermore, the collected essays from students and comments from teachers constitute a useful learner corpus. This is also of benefit to researchers in analyzing learners' persistent errors. In order to allow global access from the Internet, the system is web-based. Users, for example, students, teachers, and researchers, may access the system through web browsers. The system was developed in a cooperative effort of Computers And Networking (CAN) laboratory and the Research in English Acquisition and Pedagogy (REAP) Group at Tamkang University. The system has been piloted by six English faculty members at Tamkang University and is currently being used in five high schools in Taiwan. The learner corpus currently consists of over 800,000 word tokens of learners' writing.

A systematic continuous data placement scheme on distributed multi-zone disks is developed for video on demand. The proposed scheme makes use of constant read time concept, i. e. , each video stream has the same access time in each service round when serving the request. The developed scheme maximizes not only the averaged data transmitted rate, but also the number of simultaneous accesses. The scheme consists of the following components. First we developed an algorithm that reorganizes the multi-zone disk into several logical zones in the sense that the averaged disk throughput is maximum. Second, a sequential data access method was developed that takes disk loading balance into account. Thus, at each service round, the total amount of data transmitted is a constant. Third, we introduce the idle round technique to reduce the buffer size required at the client site for VBR video stream. As a result, admission control is enforced in an efficient manner. Finally we perform experimental tests to evaluate the performance of the proposed scheme. The results indicate the value of the proposed scheme.