It is expected that by 2003 continuous media will account for more than 50% of the data available on origin servers, this will provoke a significant change in Internet workload. Due to the high bandwidth requirements and the long-lived nature of digital video, streaming server loads and network bandwidths are proven to be major limiting factors. Aiming at the characteristics of broadband network in residential areas, this paper proposes a popularity-based server-proxy caching strategy for streaming media. According to a streaming media popularity on streaming server and proxy, this strategy caches the content of the streaming media partially or completely. The paper also proposes two formulas that calculate the popularity coefficient of a streaming media on server and proxy, and caching replacement policy. As expected, this strategy decreases the server load, reduces the traffic from streaming server to proxy, and improves client start-up latency. 相似文献
This study explored kindergartners' and first graders' collaborative processes to understand the nature of peer collaboration and the learning opportunities afforded by peer discourse. Data were drawn from 6 dyads who participated in a computer writing project for 2 school semesters. Children's videotaped interactions were analyzed with the focus on understanding how children's collaborative roles and patterns changed over time. Examination of video data and children's computer products revealed that (a) children's interaction patterns changed from a more independent style toward a more integrative style, as shown in their distribution of control over mouse and keyboard and in the written outcomes of their collaboration; (b) a shift in role patterns emerged across repeated instances of peer collaboration so that children began alternating the roles of leader and observer, and less competent children began carrying out more important tasks; and (c) the computer served as an object of reference for children to sustain their interaction and stay on task. 相似文献
This study investigated the cognitive, attitudinal and behavioural aspects of the career maturity of 1380 secondary school and junior college students.
The findings reveal a general weakness in career exploration and in the students' development of career decision-making skills. While no significant gender differences can be observed, there is strong evidence to indicate that career development does mature with age. The findings also suggest a positive association between career maturity and academic performance and between career maturity and parental involvement. Among the resource persons identified, teachers are the least consulted. They are also rated as the least helpful source of career information.
In the light of these findings, implications for the planning and implementation of career guidance in schools to enhance the career maturity of the students are discussed and suggestions made. 相似文献