The present review examined the effectiveness of three peer tutoring programs: cross-age peer tutoring, Classwide Peer Tutoring (CWPT), and Peer-Assisted Learning Strategies (PALS), for elementary students in the academic areas of math and reading. The research reviewed indicates students who participated in cross-age peer tutoring and CWPT had improved test scores on basic math facts as well as increased math scores on standardized assessments. Students also showed improvement in reading fluency, reading comprehension, spelling, and reading level after participating in cross-age peer tutoring and CWPT. High-, average-, and low-achieving students as well as students in special Ill education benefitted from these peer tutoring programs. In addition, both tutors and tutees received benefits from the tutoring programs, although fewer studies examined outcomes for tutors. Although cross-age peer tutoring, and CWPT resulted in mostly positive outcomes, this was not the case for the PALS program. Students participating in this program demonstrated little change from pre- to post-assessment. Since the PALS studies were better designed with tighter experimental control, it is less likely results were due to another variable. The cross-age and CWPT studies lacked the tight experimental control of the PALS studies.

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An integrative review was used to examine the effects of being a tutor versus not being a tutor. The matrix method was used to guide the research process, to identify articles that met the inclusion criteria, and to reduce data into common topics of peer tutoring. The results of the integrative review yielded 20 articles and suggested that students in the position to assist others are more confident in communicating in groups and have higher knowledge in the subject they help with than their fellow peers. The literature showed that students in the position to assist others have defined personal and professional standards and leadership skills. However, there is little research on the benefits of being a tutor when compared with the benefits tutees obtain from coming to tutoring sessions. More research is needed to examine the effects of being a tutor. More specifically, there are no studies where the skills of nursing student tutors are compared with nursing student non-tutors. In this study, the researcher created a survey to evaluate nursing student tutors and non-tutors, their communication and leadership skills, as well as their personal and professional growth. Focus groups were created to provide tutors a means of discussing the personal and professional impact that tutoring has had on them. The study results indicated that tutors have decreased nervousness in public speaking, have higher confidence in their communication skills, share their life experiences to help others more often, and readily reach out to instructors and other tutors for assistance.

Scalable on-demand content delivery systems, designed to effectively handle increasing request rates, typically use service aggregation or content replication techniques. Service aggregation relies on one-to-many communication techniques, such as multicast, to efficiently deliver content from a single sender to multiple receivers. With replication, multiple geographically distributed replicas of the service or content share the load of processing client requests and enable delivery from a nearby server.<p>Previous scalable protocols for downloading large, popular files from a single server include batching and cyclic multicast. Analytic lower bounds developed in this thesis show that neither of these protocols consistently yields performance close to optimal. New hybrid protocols are proposed that achieve within 20% of the optimal delay in homogeneous systems, as well as within 25% of the optimal maximum client delay in all heterogeneous scenarios considered.<p>In systems utilizing both service aggregation and replication, well-designed policies determining which replica serves each request must balance the objectives of achieving high locality of service, and high efficiency of service aggregation. By comparing classes of policies, using both analysis and simulations, this thesis shows that there are significant performance advantages in using current system state information (rather than only proximities and average loads) and in deferring selection decisions when possible. Most of these performance gains can be achieved using only local (rather than global) request information.<p>Finally, this thesis proposes adaptations of already proposed peer-assisted download techniques to support a streaming (rather than download) service, enabling playback to begin well before the entire media file is received. These protocols split each file into pieces, which can be downloaded from multiple sources, including other clients downloading the same file. Using simulations, a candidate protocol is presented and evaluated. The protocol includes both a piece selection technique that effectively mediates the conflict between achieving high piece diversity and the in-order requirements of media file playback, as well as a simple on-line rule for deciding when playback can safely commence.

Scalable on-demand content delivery systems, designed to effectively handle increasing request rates, typically use service aggregation or content replication techniques. Service aggregation relies on one-to-many communication techniques, such as multicast, to efficiently deliver content from a single sender to multiple receivers. With replication, multiple geographically distributed replicas of the service or content share the load of processing client requests and enable delivery from a nearby server.<p>Previous scalable protocols for downloading large, popular files from a single server include batching and cyclic multicast. Analytic lower bounds developed in this thesis show that neither of these protocols consistently yields performance close to optimal. New hybrid protocols are proposed that achieve within 20% of the optimal delay in homogeneous systems, as well as within 25% of the optimal maximum client delay in all heterogeneous scenarios considered.<p>In systems utilizing both service aggregation and replication, well-designed policies determining which replica serves each request must balance the objectives of achieving high locality of service, and high efficiency of service aggregation. By comparing classes of policies, using both analysis and simulations, this thesis shows that there are significant performance advantages in using current system state information (rather than only proximities and average loads) and in deferring selection decisions when possible. Most of these performance gains can be achieved using only local (rather than global) request information.<p>Finally, this thesis proposes adaptations of already proposed peer-assisted download techniques to support a streaming (rather than download) service, enabling playback to begin well before the entire media file is received. These protocols split each file into pieces, which can be downloaded from multiple sources, including other clients downloading the same file. Using simulations, a candidate protocol is presented and evaluated. The protocol includes both a piece selection technique that effectively mediates the conflict between achieving high piece diversity and the in-order requirements of media file playback, as well as a simple on-line rule for deciding when playback can safely commence.

The objective of the proposed research is to design and evaluate end-to-end solutions to support the Quality of Experience (QoE) for the Internet Protocol Television (IPTV) service. IPTV is a system that integrates voice, video, and data delivery into a single Internet Protocol (IP) framework to enable interactive broadcasting services at the subscribers. It promises significant advantages for both service providers and subscribers. For instance, unlike conventional broadcasting systems, IPTV broadcasts will not be restricted by the limited number of channels in the broadcast/radio spectrum. Furthermore, IPTV will provide its subscribers with the opportunity to access and interact with a wide variety of high-quality on-demand video content over the Internet. However, these advantages come at the expense of stricter quality of service (QoS) requirements than traditional Internet applications. Since IPTV is considered as a real-time broadcast service over the Internet, the success of the IPTV service depends on the QoE perceived by the end-users. The characteristics of the video traffic as well as the high-quality requirements of the IPTV broadcast impose strict requirements on transmission delay. IPTV framework has to provide mechanisms to satisfy the stringent delay, jitter, and packet loss requirements of the IPTV service over lossy transmission channels with varying characteristics. The proposed research focuses on error recovery and channel change latency problems in IPTV networks. Our specific aim is to develop a content delivery framework that integrates content features, IPTV application requirements, and network characteristics in such a way that the network resource utilization can be optimized for the given constraints on the user perceived service quality. To achieve the desired QoE levels, the proposed research focuses on the design of resource optimal server-based and peer-assisted delivery techniques. First, by analyzing the tradeoffs on the use of proactive and reactive repair techniques, a solution that optimizes the error recovery overhead is proposed. Further analysis on the proposed solution is performed by also focusing on the use of multicast error recovery techniques. By investigating the tradeoffs on the use of network-assisted and client-based channel change solutions, distributed content delivery frameworks are proposed to optimize the error recovery performance. Next, bandwidth and latency tradeoffs associated with the use of concurrent delivery streams to support the IPTV channel change are analyzed, and the results are used to develop a resource-optimal channel change framework that greatly improves the latency performance in the network. For both problems studied in this research, scalability concerns for the IPTV service are addressed by properly integrating peer-based delivery techniques into server-based solutions.

Peer tutoring as an instructional strategy has been used by school personnel to increase academic achievement in the classroom setting. Traditionally, the peer tutoring concept relies on student partnerships linking higher achieving students with lower achieving students for structured reading sessions. Recently, new studies have focused on linking students with comparable reading achievements or cross-age peer tutors. Research suggests that using peer tutors may promote higher reading fluency in at-risk students as compared to teacher instruction. A potential reason for this phenomenon includes students’ comfort level with peers allowing for a more easy development of reading growth. The purpose of this study is to determine the effectiveness, efficiency, and scalability of cross-age peer tutoring on reading fluency and reading comprehension. The study involved 7 fifth grade struggling readers as tutors to 7 third grade struggling readers. Reading to Read was used as the intervention protocol. The dyads met for 5 weeks with progress monitoring conducted at the beginning of each week. Results indicated consistent benefit in improving reading fluency in 13 of the 14 participants. Several implications to the study can be identified. Peer assisted learning can benefit both participants in reading fluency. Participating in the peer assisted learning process improves the attitudes toward reading of below grade level readers. Further implications, limitations, and future research relating to the results of this study are also discussed.