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
Using latent variable structural equation modeling, a family economic stress model that links economic well-being to child well-being in an ethnically diverse, low-income sample of 419 elementary school-age children was evaluated. The sample was 57% African American and 28% Hispanic, and most families were headed by single mothers. The results provided support for the position that family process is a critical mediator of the effects of economic hardship on children's social adjustment. Lower levels of economic well-being, and the corollary elevated perceptions of economic pressure indirectly affected parenting behavior through an adverse impact on parental psychological well-being. Distressed parents reported feeling less effective and capable in disciplinary interactions with their child and were observed to be less affectionate in parent-child interactions. In turn, less than optimal parenting predicted lower teacher ratings of children's positive social behavior and higher ratings of behavior problems. Multiple-group analyses revealed that the pathways by which economic hardship influences children's behavior appear to operate similarly for boys and girls, and for African American and Hispanic families. 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