PicShark: mitigating metadata scarcity through large-scale P2P collaboration

With the commoditization of digital devices, personal information and media sharing is becoming a key application on the pervasive Web. In such a context, data annotation rather than data production is the main bottleneck. Metadata scarcity represents a major obstacle preventing efficient information processing in large and heterogeneous communities. However, social communities also open the door to new possibilities for addressing local metadata scarcity by taking advantage of global collections of resources. We propose to tackle the lack of metadata in large-scale distributed systems through a collaborative process leveraging on both content and metadata. We develop a community-based and self-organizing system called PicShark in which information entropy—in terms of missing metadata—is gradually alleviated through decentralized instance and schema matching. Our approach focuses on semi-structured metadata and confines computationally expensive operations to the edge of the network, while keeping distributed operations as simple as possible to ensure scalability. PicShark builds on structured Peer-to-Peer networks for distributed look-up operations, but extends the application of self-organization principles to the propagation of metadata and the creation of schema mappings. We demonstrate the practical applicability of our method in an image sharing scenario and provide experimental evidences illustrating the validity of our approach. The work presented in this article was supported by the Swiss NSF National Competence Center in Research on Mobile Information and Communication Systems (NCCR MICS, grant number 5005-67322), by the EPFL Center for Global Computing as part of the European project NEPOMUK No FP6-027705, and by the Líon project supported by Science Foundation Ireland under Grant No. SFI/02/CE1/I131.     

A scalable P2P platform for the knowledge grid

The knowledge grid needs to operate with a scalable platform to provide large-scale intelligent services. A key function of such a platform is to efficiently support various complex queries in a dynamic large-scale network environment. This paper proposes a platform to support index-based path queries by incorporating a semantic overlay with an underlying structured P2P network that provides object location and management services. Various distributed indexing structures can be dynamically formed by publishing, semantic objects as indexing nodes. Queries are forwarded along the chains of semantic object pointers to search for objects. We investigate the deployment of a scalable distributed trie index for broadcast queries on key strings, propose a decentralized load balancing method for solving the problem of uneven load distribution incurred by heterogeneity of loads and node capacities and by the distributed trie index, and give an approach for improving the availability of the semantic overlay and its trie index. Experiments demonstrate the scalability of the proposed platform.     

Modelling with knowledge: A review of emerging semantic approaches to environmental modelling

Models, and to a lesser extent datasets, embody sophisticated statements of environmental knowledge. Yet, the knowledge they incorporate is rarely self-contained enough for them to be understood and used – by humans or machines – without the modeller's mediation. This severely limits the options in reusing environmental models and connecting them to datasets or other models. The notion of “declarative modelling” has been suggested as a remedy to help design, communicate, share and integrate models. Yet, not all these objectives have been achieved by declarative modelling in its current implementations.Semantically aware environmental modelling is a way of designing, implementing and deploying environmental datasets and models based on the independent, standardized formalization of the underlying environmental science. It can be seen as the result of merging the rationale of declarative modelling with modern knowledge representation theory, through the mediation of the integrative vision of a Semantic Web. In this paper, we review the present and preview the future of semantic modelling in environmental science: from the mediation approach, where formal knowledge is the key to automatic integration of datasets, models and analytical pipelines, to the knowledge-driven approach, where the knowledge is the key not only to integration, but also to overcoming scale and paradigm differences and to novel potentials for model design and automated knowledge discovery.     

Fostering collective and individual learning through knowledge building

The purpose of this study was to design and examine a computer-supported knowledge-building environment and to investigate both collective knowledge-building dynamics and individual learning in the context of a tertiary education course in mainland China. The participants were 102 students in four intact Year-one tertiary business classes. Two classes experienced a knowledge-building environment (CKB) and the other two were taught using a regular project-based approach (RPBL). Data were obtained from interactions in the forum, writing quality, group-learning portfolios, and surveys. Quantitative analyses indicated that the knowledge-building groups outperformed the comparison groups on academic literacy assessed in terms of conceptual understanding and explanation, and obtained higher scores on beliefs about collaboration. Within-group analyses indicated that the students’ engagement in Knowledge Forum was a significant predictor of their academic literacy. Qualitative contrastive analyses of high- and low-performance groups identified different patterns of conceptual, metacognitive and social processes, and showed that student groups engaging in more collective and meta-discourse discourse moves performed better on individual scores in academic literacy. The implications of examining both collaborative dynamics and individual learning and designing computer-supported knowledge building for tertiary students are discussed.     

语义为核心的多文种信息处理平台的模型

提出了一个基于语义、面向自然语言处理的多文种信息处理平台的模型SMIPP.该模型主要由应用程序/用户接口层、文字输入层和文字输出层、信息处理服务层、语料库层、多文种代码体系SemaCode层和语言Ontology层组成,该平台把各种语言文字统一用具有自描述能力的SemaCode表示,并通过语言Ontology来表示词汇的语义以及在各个文种间的联系,再通过服务形式提供各种基于语料库的文字信息处理功能,是一个全新的多文种信息处理模型.     

基于Cloud-P2P网络平台的泛知识云模型

提出一种云计算与对等计算融合模型Cloud-P2P, 并基于Cloud-P2P构建一种新颖的泛知识云系统, 将网络中的各类文献、知识信息有序地组织在一起; 充分考虑网络边缘节点上可以利用的资源, 在保障用户使用体验的前提下, 将用户提交的知识索取任务从网络中心的服务器端迁移到网络边缘的客户端。为进一步改善用户的使用体验, 提出一种动态的复合自适应QoS保障机制, 通过综合区分用户与资源类型, 并设定服务器负载阈值, 解决传统知识系统中存在的高峰阶段服务器性能瓶颈的难题, 从而达到提高系统中用户整体普遍满意度的目标。     

From P2P to reliable semantic P2P systems

Current research to harness the power of P2P networks involves building reliable Semantic Peer-to-Peer (SP2P) systems. SP2P systems combine two complementary technologies: P2P networking and ontologies. There are several types of SP2P systems with applications to knowledge management systems, databases, the Semantic Web, emergent semantics, web services, and information systems. Correct semantic mapping is fundamental for success of SP2P systems where semantic mapping refers to semantic relationship between concepts from different ontologies. Current research on SP2P systems has emphasized semantics at the cost of dealing with the traditional issues of P2P networks of reliability and scalability. As a result of their lack of resilience to temporary mapping faults, SP2P systems can suffer from disconnection failures. Disconnection failures arise when SP2P systems that use adaptive query routing methods treat temporary mapping faults as permanent mapping faults. This paper identifies the disconnection failure problem due to temporary semantic mapping faults and proposes an algorithm to resolve it. To identify the problem, we will use a simulation model of SP2P systems. The Fault-Tolerant Adaptive Query Routing (FTAQR) algorithm proposed to resolve the problem is an adaptation of the generous tit-for-tat method originally developed in evolutionary game theory. The paper demonstrates that the reliability of an SP2P system increases by using the algorithm.     

Team leader strategies for enabling collaboration technology adaptation: team technology knowledge to improve globally distributed systems development work

Active management of team adaptation of collaboration technologies offers an important lever for influencing success rates in distributed project work, particularly in settings characterized by high task interdependence, such as information systems development (ISD). Substantial uncertainty exists as to how a leader might influence such technology adaptation during project work. Prior research indicates that a major leader resource to accomplish technology adaptation in these settings would be team technology knowledge (TTK). This empirical field study develops a five-factor model of strategies regarding awareness of TTK that team leaders take in intervening to affect technology adaptation in distributed ISD projects. The analysis indicates insights into when and why these strategies are effective and how they relate to each other as well as the leader's awareness of TTK. The study provides a way for ISD team leaders to approach improving team collaboration from a socio-technical perspective as well as insights into potential levers for improving team technology adaptation and the efficacy of ISD projects.     

New knowledge in strategic management through visually mining semantic networks

Today’s highly competitive business world requires that managers be able to make fast and accurate strategic decisions, as well as learn to adapt to new strategic challenges. This necessity calls for a deep experience and a dynamic understanding of strategic management. The trait of dynamic understanding is mainly the skill of generating additional knowledge and innovative solutions under the new environmental conditions. Building on the concepts of information processing, this paper aims to support managers in constructing new strategic management knowledge, through representing and mining existing knowledge through graph visualization. To this end, a three-stage framework is proposed and described. The framework can enable managers to develop a deeper understanding of the strategic management domain, and expand on existing knowledge through visual analysis. The model further supports a case study that involves unstructured knowledge of profit patterns and the related strategies to succeed using these patterns. The applicability of the framework is shown in the case study, where the unstructured knowledge in a strategic management book is first represented as a semantic network, and then visually mined for revealing new knowledge.     

结构化多点协作 P2 P系统研究 *

Chord是一种典型的分布式结构化的 P2P系统 ,具有严格的结构 ,无须服务器就可以很方便地找到需要的节点和数据 ;但是该系统中 ,一个文件只有一个备份 ,容易造成文件丢失 ,而且文件传输速度很慢。为此 ,在 Chord算法的基础上进行了改进 ,设计了结构化多点协作 P2P系统。该系统兼备 BitTorrent和 Chord的优点 ,既可以无须服务器方便地找到需要的节点和数据 ,又可以进行多点协作下载 ,从而保证了下载速度。它很好地解决了以上问题 ,大大提高了系统的执行效率。     

A decision-making model for knowledge collaboration and reuse through scientific workflow

Past, present and future, to realize the aim of product CTQS (i.e., lower cost, faster time to market, higher quality and better service) with manufacturing intelligence, few manufacturers have no longer engaged in product related production decision support problem (P-DSP). However, P-DSP solving (P-DSPS) is a multi-criteria decision-making problem, which is context sensitive in solution objects-attributes and chaos in the decision process of manufacturing knowledge collaboration and reuse. To alleviate these limitations, this paper presents a novel triple deep workflow model for P-DSPS. Driven by a wicked task query, the proposed workflow of P-DSPS (WP-DSPS) has the function to retrieve similarity-based alternatives from domain knowledge driven solution flow (KSF) and to evaluate with expert knowledge collaboration from knowledge driven decision flow (KDF) based on utility theory under the task event driven control flow (ECF) strategy and operation logic. In the view of alternative adaption, a domain knowledge ontology-based degree of similarity (DoS) determines the P-DSPS alternatives width, a utility function-based degree of decision (DoD) determines alternatives quality, and a belief-based knowledge fusion technique is used to synthesize decision conflicts with a consensus degree (CD). To support the proposed models, a workflow-based system prototype is proposed and validated in two case studies.     

基于U-P2P元组空间知识协作模式的中越跨语言查询扩展

针对中国与东盟国家在知识共享过程中的语言障碍问题, 详细阐述跨语言查询扩展元组空间的逻辑结构, 提出U-P2P网络模式下元组空间知识协作的分布式中、越跨语言查询扩展模型。在此基础上, 增加查询扩展代理peer的动作语言规则的定义和元组元操作指令集, 依据强化学习算法提出一种基于加权矩阵的自适应路由选择/查询机制。在Gnutella环境下的实验表明, 相对于传统的集中式查询而言, 该模型对中越两种语言之间的快速翻译和扩展查询具有较好的准确率和召回率, 在不同知识领域的运用中具有通用性和可扩充性。     

基于分类节点的P2P语义路由模型

对于P2P语义覆盖网络,语义信息的维护和智能路径的选择是实现的难点。根据小世界原理,提出了一种新的基于节点分类划分的P2P语义路由模型。通过建立节点本体来描述节点的网络结构和节点下的内容项,在此基础上创建了路由消息格式和节点分类划分的方法,然后创建了支持内容语义查询的节点内相关性内容查询算法和节点间消息路由算法。通过实验对比,该语义路由模型能够提高P2P系统下的内容查找速度并且能够显著降低占用的网络带宽。     

The need for systems development capability in design science research: enabling researcher-systems developer collaboration

Information systems as an artefact-oriented discipline require a strong interaction between researchers, developers and users regarding design of, development of, and the study of the use of digital artefacts in social settings. During recent years, performing research in a design science research spirit has gained increasing interest. In larger scale design research endeavours, access to systems development capabilities becomes necessary. Such a unit, InnovationLab, was established in 2006 in a university setting in Sweden. In this paper we are investigating the 5 years’ experience of running this InnovationLab. Our findings point to an innovation lab being valuable for research in general and especially for design science research. However, in order to balance the business of an innovation lab, it will be necessary to provide services for other stakeholders (such as administrative units, teachers, and students) as a means for developing systems development capability aimed at supporting researchers.     

Entity Notation: enabling knowledge representations for resource-constrained sensors

The forthcoming ambient systems will contain a large amount of sensors. Representing the data produced by these sensors in a format suitable for ambient intelligence applications would enable a large number of useful services. However, such formats tend to require processing power and communication bandwidth not available in many sensors utilizing ultra low-power microcontrollers and radio chip solutions. This paper presents a lightweight data representation, Entity Notation, to tackle this problem. Sensors with limited computation and communication capabilities can use Entity Notation to describe the data they produce. Entity Notation can be transformed into knowledge representations in a straightforward manner, and hence, the data produced by sensor nodes can be utilized with ease by any ambient intelligence system compatible with the common knowledge representations. This paper presents the design of Entity Notation, its implementations on embedded sensors and the evaluation of its performance.     

The collaboration of two different working practices enabling autonomous virtual reality artwork

This paper describes the collaboration process between a fine arts sculptor and a virtual reality (VR) designer resulting in the sculptor being able to autonomously produce a VR art exhibition. The two different creative methodologies are reviewed through interviews, observations and reflections. The development of the installation is recorded describing the decisions made and methods used to enable the sculptor to remain independent during his creative endeavour.     

P2PSpaceTwist:一种主动式用户协作的位置隐私保护方法

随着定位技术和无线移动设备的飞速发展,移动用户能够随时随地获取位置信息,也可能泄露位置信息,甚至导致个人隐私的泄露。提出了一种主动式用户协作的位置隐私保护方法—P2PSpaceTwist,该方法采用了一种带新鲜性的主动式协商机制,通过该机制用户主动与邻居协商,收集邻居信息并广播自身信息;当满足用户的匿名需求后,使用匿名区域内的随机位置代替用户的真实位置并发送给随机选定的代理,通过代理向位置服务器提供商发送增量式的近邻查询,从而获得精确的结果集。实验结果表明,P2PSpaceTwist能够较快地实现匿名查询并获得较精确的结果集,与其他位置隐私保护方法相比,P2PSpaceTwist的通信开销较低。     

P2P备份系统的协作机制研究

P2P备份系统已经成为确保数据可用的解决方案之一,它的关键思想是利用P2P网络节点的空闲存储空间来存储数据.由于P2P网络是一个高动态的环境,该系统的主要缺陷是对等节点之间缺乏协作机制.为了解决这个缺陷,系统定义一组时间表,它模拟每一个节点的可用性和需求,解决节点之间的备份协作问题并且确保有效的使用节点资源.仿真实验结果表明,基于时间表协作机制能改善P2P备份系统的性能.     

P2P协同工作环境下的一种多媒体认证系统

为了适应P2P协同工作中的安全需求，针对多媒体数据的特殊性，探讨了传统的多媒体认证方法，提出了一种结合数字签名和数字水印的多媒体信息认证方案，系统利用JXTA平台的安全特性，采用双重身份及易损水印的认证机制，使得非法篡改、伪造多媒体信息更加困难。分析表明，该方案具有安全性高、可信度高等特点，适用于图像、数据等多媒体的安全传输。     

A framework for semantic grouping in P2P databases

Sharing of structured data in decentralized environments is a challenging problem, especially in the absence of a global schema. Social network structures map network links to semantic relations between participants in order to assist in efficient resource discovery and information exchange. In this work, we propose a scheme that automates the process of creating schema synopses from semantic clusters of peers which own autonomous relational databases. The resulting mediated schemas can be used as global interfaces for relevant queries. Active nodes are able to initiate the group schema creation process, which produces a mediated schema representative of nodes with similar semantics. Group schemas are then propagated in the overlay and used as a single interface for relevant queries. This increases both the quality and the quantity of the retrieved answers and allows for fast discovery of interest groups by joining peers. As our experimental evaluations show, this method increases both the quality and the quantity of the retrieved answers and allows for faster discovery of semantic groups by joining peers.