Research issues in peer-to-peer data management

Data management in Peer-to-Peer (P2P) systems is a complicated and challenging issue due to the scale of the network and highly transient population of peers. In this paper, we identify important research problems in P2P data management, and describe briefly some methods that have appeared in the literature addressing those problems. We also discuss some open research issues and directions regarding data management in P2P systems. ©2007 IEEE

Distributed Reasoning in a Peer-to-Peer Setting: Application to the Semantic Web

In a peer-to-peer inference system, each peer can reason locally but can also solicit some of its acquaintances, which are peers sharing part of its vocabulary. In this paper, we consider peer-to-peer inference systems in which the local theory of each peer is a set of propositional clauses defined upon a local vocabulary. An important characteristic of peer-to-peer inference systems is that the global theory (the union of all peer theories) is not known (as opposed to partition-based reasoning systems). The main contribution of this paper is to provide the first consequence finding algorithm in a peer-to-peer setting: DeCA. It is anytime and computes consequences gradually from the solicited peer to peers that are more and more distant. We exhibit a sufficient condition on the acquaintance graph of the peer-to-peer inference system for guaranteeing the completeness of this algorithm. Another important contribution is to apply this general distributed reasoning setting to the setting of the Semantic Web through the Somewhere semantic peer-to-peer data management system. The last contribution of this paper is to provide an experimental analysis of the scalability of the peer-to-peer infrastructure that we propose, on large networks of 1000 peers

Exploiting peer group concept for adaptive and highly available services

This paper presents a prototype for redundant, highly available and fault tolerant peer to peer framework for data management. Peer to peer computing is gaining importance due to its flexible organization, lack of central authority, distribution of functionality to participating nodes and ability to utilize unused computational resources. Emergence of GRID computing has provided much needed infrastructure and administrative domain for peer to peer computing. The components of this framework exploit peer group concept to scope service and information search, arrange services and information in a coherent manner, provide selective redundancy and ensure availability in face of failure and high load conditions. A prototype system has been implemented using JXTA peer to peer technology and XML is used for service description and interfaces, allowing peers to communicate with services implemented in various platforms including web services and JINI services. It utilizes code mobility to achieve role interchange among services and ensure dynamic group membership. Security is ensured by using Public Key Infrastructure (PKI) to implement group level security policies for membership and service access.Comment: The Paper Consists of 5 pages, 6 figures submitted in Computing in High Energy and Nuclear Physics, 24-28 March 2003 La Jolla California. CHEP0

The development and deployment of a maintenance operations safety survey

Objective: Based on the line operations safety audit (LOSA), two studies were conducted to develop and deploy an equivalent tool for aircraft maintenance: the maintenance operations safety survey (MOSS). Background: Safety in aircraft maintenance is currently measured reactively, based on the number of audit findings, reportable events, incidents, or accidents. Proactive safety tools designed for monitoring routine operations, such as flight data monitoring and LOSA, have been developed predominantly for flight operations. Method: In Study 1, development of MOSS, 12 test peer-to-peer observations were collected to investigate the practicalities of this approach. In Study 2, deployment of MOSS, seven expert observers collected 56 peer-to-peer observations of line maintenance checks at four stations. Narrative data were coded and analyzed according to the threat and error management (TEM) framework. Results: In Study 1, a line check was identified as a suitable unit of observation. Communication and third-party data management were the key factors in gaining maintainer trust. Study 2 identified that on average, maintainers experienced 7.8 threats (operational complexities) and committed 2.5 errors per observation. The majority of threats and errors were inconsequential. Links between specific threats and errors leading to 36 undesired states were established. Conclusion: This research demonstrates that observations of routine maintenance operations are feasible. TEM-based results highlight successful management strategies that maintainers employ on a day-to-day basis. Application: MOSS is a novel approach for safety data collection and analysis. It helps practitioners understand the nature of maintenance errors, promote an informed culture, and support safety management systems in the maintenance domain

Query processing in peer-to-peer based data management system

Ph.DDOCTOR OF PHILOSOPH

Effectiveness of a peer-led self-management program for older people with type 2 diabetes in China

Type 2 diabetes is a common chronic disease, which has a negative health impact and results in enormous economic burden. The prevalence of type 2 diabetes is increasing dramatically and it affects older people disproportionately. The healthcare system in China is faced with an overwhelming burden due to a large ageing population, high prevalence of diabetes and limited healthcare resources. Self-management has been widely accepted as the cornerstone of the clinical management of type 2 diabetes. Since self-management usually involves complex behaviour change and can be emotionally challenging, effective education is essential to facilitate this transition. However, there has been no existing program of type 2 diabetes self-management for older patients in China until now. Furthermore, the generalisation of any health education programs is often hampered due to limited healthcare resources in China. The primary purpose of this study was to develop a socially and culturally suitable self-management program, which addressed self-efficacy and social support to facilitate behaviour change and subsequent health improvement, for older people with type 2 diabetes living in the community in China. The secondary purpose was to test a feasible delivery model of the program through involvement of peer leaders and existing community networks. This study was conducted in three phases. Phase one gathered information about barriers related to self-management behaviours and help needed to address them, from the perspective of older people with type 2 diabetes and community health professionals, through focus group discussion. Data from Phase One, together with guidelines of the selected theoretical frame work, results from an extensive literature review, and experiences of previous relevant studies provided the basis for development of a peer-led type 2 diabetes self-management program (Phase Two). Phase Three involved a pre-test, post-test non-equivalent control group design to test the effectiveness of the self-management program on older people with type 2 diabetes in the community. The impact of the program on peer leaders was examined using a one group pre-test, post-test design. In addition, evaluation of the program from peer leaders’ and older people’s perceptions was conducted through a post-test questionnaire. Older people with type 2 diabetes and health professionals expressed broadly the same concerns, which were: social support; confidence to practice self-management behaviours; self-management behaviours; barriers to self-management behaviours; and advice for ongoing health education. However, their points of view were not always identical and different emphases were identified. The peer-led program produced significant improvement in social support, self-efficacy, self-management behaviours and depressive status in the experimental group, as compared to the non-equivalent control group. However, there was no significant effect on quality of life nor health care utilisation. Therefore, the effectiveness of the program among older people with type 2 diabetes was partially confirmed. In addition, the participants were supportive, giving positive feedback about the program. Suggestions for future improvement were provided as well. After receiving specific peer leader training and assisting in most of the delivery process of the program, the peer leaders improved, significantly, in overall self-management behaviours and in specific areas of social support and self-efficacy, though they did not improve in depressive status, quality of life and health care utlisation. In addition, these peer leaders enjoyed being peer leaders, and gave very positive feedback about the whole program. In conclusion, this study has implications for understanding and facilitating self-management behaviours for older people with type 2 diabetes in China. The peer-led self-management program was effective in improving levels of self-efficacy, social support, self-management behaviours and depressive status among older people with type 2 diabetes living in the community in China. The delivery process involving peer leaders was deemed feasible to implement within the health care system in China. The program is suitable to be used by community health professionals in their practice in China. The study also has potential wider benefit to nursing practice and global health practice

Design and Implementation of Peer to Peer Credit Risk Management System Based on Big Data Analysis

作为互联网金融典型代表，P2P网络借贷引起社会各方面的高度关注。同时受经济全球化和全球信息化、人类社会发展和需求多样性、云计算和物联网技术深化应用等方面的影响，“大数据”(bigdata)已经成为IT领域和互联网上反复提及的热词。国内P2P网贷行业面临的系统风险、信用风险、平台风险等正在不断积累、扩大，如何有效防范P2P网络借贷风险迫在眉睫。本文从国内典型的P2P平台拍拍贷中抓取实际有效的数据，经过本系统分析得到结果，希望能够对P2P行业具有一定的指导作用。 基于大数据分析的P2P信贷风险管理系统通过开发网络爬虫实时与被采集网站连接，自动使用配置好的已注册帐号通过模拟人工登录的方式登录网站，...P2P network lending, a typical representative of internet finance, has attracted a lot of public attention. Scandals such as causing investors penniless is not uncommon due to the low entry threshold, legal lag, lack of supervision and incomplete personal credit system of the P2P network lending industry. Domestic P2P network lending industry is now facing accumulating and expanding systematic ris...学位：工程硕士院系专业：软件学院_工程硕士(软件工程)学号：X201323075

Computer assisted self and peer assessment: applications, challenges and opportunities

This paper discusses self and peer assessment (SPA) using CASPAR (Computer Assisted Self and Peer Assessment Ratings) – a software tool designed to aid the administration of SPA. CASPAR was piloted on eight units from six subject areas (Hospitality, Leisure, Sport, Tourism, Retail and Events). Data were gathered through questionnaires from 146 students. The paper compares the SPA process and the application of CASPAR in a hospitality operations management unit with other units to identify good practice

Software Framework for Peer Data-Management Services

Object Oriented Data Technology (OODT) is a software framework for creating a Web-based system for exchange of scientific data that are stored in diverse formats on computers at different sites under the management of scientific peers. OODT software consists of a set of cooperating, distributed peer components that provide distributed peer-to-peer (P2P) services that enable one peer to search and retrieve data managed by another peer. In effect, computers running OODT software at different locations become parts of an integrated data-management system