Hop selection in peer-to-peer WPAN networks

Currently, wireless technology is revolutionizing the way we share information and communicate. The demands for mobility have made wireless technology the primary source for voice communication. Code-division multiple-access (CDMA) is a very popular spread spectrum application due to its claims of low transmission power, higher system capacity, ability to mitigate multipath fading and user interference. In that case, frequency-hopping code-division multiple access (FH-CDMA) has received considerable attention over the past few years. This technique will allow a better performance over a fading channel, message privacy, and immunity to narrowband interference. This paper addresses the characteristics of FH-CDMA in WPAN networks, with an emphasis on frequency-hopped Bluetooth systems. A performance evaluation of FH-CDMA is discussed and simulated. The analysis shows the interaction between the designed parameters and their effect on the network system. Most specifically, the FH-CDMA scheme provides frequency and temporal diversity to combat the effects of interference.

Peer mentoring in Higher Education:a reciprocal route to student success

This paper provides an introduction to the findings of a large HEFCE/Paul Hamlyn-sponsored project, which aimed to investigate and analyse the value of peer mentoring in facilitating a successful transition into higher education.

Peer mentoring and experiential learning:the pathway to success

An analysis of the value of peer mentoring as an experiential learning approach

Peer mentoring in higher education:a multidimensional approach to conceptualising the role of peer mentoring programmes in enhancing the first year undergraduate experience

Across the literature researchers agree that the concept of mentoring results in positive outcomes for both mentors and mentees alike (Enrich et al, 2004). From a pedagogical perspective, student focused mentoring activities in Higher Education are generally perceived to comprise dyadic or triadic relationships that encapsulate a diverse range of learning strategies and/or support mechanisms. Whilst there exists a significant amount of literature regarding the wider value of Peer Mentoring in Higher Education, there remains a notable gap in knowledge about the value of such programmes in enhancing the first year undergraduate experience and thus promoting a smooth transition to University. Using the emergent study findings of a large international project, a multidimensional conceptual framework bringing together the theoretical, conceptual and contextual determinants of Peer Mentoring is proposed. This framework makes a distinctive contribution to current pedagogical theory and practice – particularly in relation to the first year experience.

Peer Support: An Intervention To Facilitate Second Language Acquisition In Students With Asperger Syndrome And Primary Language Deficits

This is a study of a peer support program to aid students in secondary school struggling to learn a second language (for college entrance requirements) who have Asperger Syndrone and primary language deficits.

Peer Support to Facilitate Knowledge Sharing on Complex Tasks

This thesis explores how to design a peer support system to facilitate self-organized knowledge sharing in non-formal learning environments, in particular when learners work on complex tasks. The peer support system aims to replace two teacher-led didactic arrangements: selecting a tutor at the initial stage, and guidance during the interaction process (Dillenbourg, 1999; Topping, 1996). Such a system has previously been developed by Van Rosmalen (2008) and De Bakker (2010) and has been tentatively used to facilitate knowledge sharing on content-related questions. In this thesis, we would like to find out how to further improve the design of this peer support system, especially to facilitate knowledge sharing on complex tasks. Since little pedagogical theory is available to inform the design of our peer support system, this thesis attempts to apply cognitive load theory (Sweller, Van Merriënboer, & Paas, 1998; Van Merriënboer & Sweller, 2005) that informs instructional designs in classroom settings to the design of our peer support system in Learning Networks.

Clustering-based Query Routing in Cooperative Semi-structured Peer to Peer Networks

We consider the problem of resource selection in clustered Peer-to-Peer Information Retrieval (P2P IR) networks with cooperative peers. The clustered P2P IR framework presents a significant departure from general P2P IR architectures by employing clustering to ensure content coherence between resources at the resource selection layer, without disturbing document allocation. We propose that such a property could be leveraged in resource selection by adapting well-studied and popular inverted lists for centralized document retrieval. Accordingly, we propose the Inverted PeerCluster Index (IPI), an approach that adapts the inverted lists, in a straightforward manner, for resource selection in clustered P2P IR. IPI also encompasses a strikingly simple peer-specific scoring mechanism that exploits the said index for resource selection. Through an extensive empirical analysis on P2P IR testbeds, we establish that IPI competes well with the sophisticated state-of-the-art methods in virtually every parameter of interest for the resource selection task, in the context of clustered P2P IR.

Childhood Attention Problems and the Development of Comorbid Symptoms at the Transition to High School: The Mediating Role of Parent and Peer Relationships

Children with Attention-Deficit/Hyperactivity Disorder (ADHD) are at increased risk for the development of depression and delinquent behavior. Children and adolescents with ADHD also experience difficulty creating/maintaining high quality friendships and parent-child relationships, and these difficulties may contribute to the development of co-morbid internalizing and externalizing symptoms in adolescence. However, there is limited research examining whether high quality friendships and parent-child relationships mediate the relation between ADHD and the emergence of these co-morbid symptoms at the transition to high school. This study examines the mediating role of relationship quality in the association between ADHD and depressive symptoms/delinquent behaviors at this developmentally significant transition point. Results revealed significant indirect effects of grade 6 attention problems on grade 9 depressive symptoms through friendship quality and quality of the mother-child relationship in grade 8. Interventions targeting parent and peer relationships may be valuable for youth with ADHD to promote successful transitions to high school.

Individual Differences in Reactions to Peer Victimization: The Moderating Role of Temperament and Sex

This study examined whether temperamental traits and sex moderate the effects of peer victimization on children’s adjustment over a year to identify factors that put victimized children at heightened risk for adjustment difficulties. Children (N = 282; M age = 7.94 years, SD = 0.32) and teachers reported on exposure to peer victimization. Parents provided ratings of children’s temperament (i.e., inhibitory control and negative emotionality) and depressive symptoms, and teachers provided ratings of children’s aggression. Results revealed that overt victimization predicted aggression in girls with low levels of inhibitory control. Results also revealed that total victimization predicted depressive symptoms in girls with high levels of negative emotionality and in boys with low levels of negative emotionality. This research identifies temperament and sex as contributors to individual differences in children’s reactions to peer victimization. The findings are discussed in the context of temperament x environment and diathesis-stress frameworks.

Query routing in cooperative semi-structured peer-to-peer information retrieval networks

Conventional web search engines are centralised in that a single entity crawls and indexes the documents selected for future retrieval, and the relevance models used to determine which documents are relevant to a given user query. As a result, these search engines suffer from several technical drawbacks such as handling scale, timeliness and reliability, in addition to ethical concerns such as commercial manipulation and information censorship. Alleviating the need to rely entirely on a single entity, Peer-to-Peer (P2P) Information Retrieval (IR) has been proposed as a solution, as it distributes the functional components of a web search engine – from crawling and indexing documents, to query processing – across the network of users (or, peers) who use the search engine. This strategy for constructing an IR system poses several efficiency and effectiveness challenges which have been identified in past work. Accordingly, this thesis makes several contributions towards advancing the state of the art in P2P-IR effectiveness by improving the query processing and relevance scoring aspects of a P2P web search. Federated search systems are a form of distributed information retrieval model that route the user’s information need, formulated as a query, to distributed resources and merge the retrieved result lists into a final list. P2P-IR networks are one form of federated search in routing queries and merging result among participating peers. The query is propagated through disseminated nodes to hit the peers that are most likely to contain relevant documents, then the retrieved result lists are merged at different points along the path from the relevant peers to the query initializer (or namely, customer). However, query routing in P2P-IR networks is considered as one of the major challenges and critical part in P2P-IR networks; as the relevant peers might be lost in low-quality peer selection while executing the query routing, and inevitably lead to less effective retrieval results. This motivates this thesis to study and propose query routing techniques to improve retrieval quality in such networks. Cluster-based semi-structured P2P-IR networks exploit the cluster hypothesis to organise the peers into similar semantic clusters where each such semantic cluster is managed by super-peers. In this thesis, I construct three semi-structured P2P-IR models and examine their retrieval effectiveness. I also leverage the cluster centroids at the super-peer level as content representations gathered from cooperative peers to propose a query routing approach called Inverted PeerCluster Index (IPI) that simulates the conventional inverted index of the centralised corpus to organise the statistics of peers’ terms. The results show a competitive retrieval quality in comparison to baseline approaches. Furthermore, I study the applicability of using the conventional Information Retrieval models as peer selection approaches where each peer can be considered as a big document of documents. The experimental evaluation shows comparative and significant results and explains that document retrieval methods are very effective for peer selection that brings back the analogy between documents and peers. Additionally, Learning to Rank (LtR) algorithms are exploited to build a learned classifier for peer ranking at the super-peer level. The experiments show significant results with state-of-the-art resource selection methods and competitive results to corresponding classification-based approaches. Finally, I propose reputation-based query routing approaches that exploit the idea of providing feedback on a specific item in the social community networks and manage it for future decision-making. The system monitors users’ behaviours when they click or download documents from the final ranked list as implicit feedback and mines the given information to build a reputation-based data structure. The data structure is used to score peers and then rank them for query routing. I conduct a set of experiments to cover various scenarios including noisy feedback information (i.e, providing positive feedback on non-relevant documents) to examine the robustness of reputation-based approaches. The empirical evaluation shows significant results in almost all measurement metrics with approximate improvement more than 56% compared to baseline approaches. Thus, based on the results, if one were to choose one technique, reputation-based approaches are clearly the natural choices which also can be deployed on any P2P network.

Using online peer assessment tools to provide feedback and promote learning

A set of slides used for the RAP SIG event on 19 Jan 2017