动态自适应安全的（k,n）先应秘密共享系统设计

针对目前先应秘密共享系统基于经验方法的安全参数设置问题,本文将安全检测技术与先应秘密共享方案相结合,提出了动态自适应安全的先应秘密共享系统结构和响应方法.利用系统的安全审计日志,在评估移动攻击安全风险的基础上,分析了系统的共享服务器组由起始安全向入侵转移的渐进过程,建立了系统的状态转移模型,给出了系统的安全性定量分析和评估方法.并且,通过比较不同的门限配置、入侵率和安全阈值等参数情况,说明了维持先应秘密共享系统安全性的一般步骤,通过动态调整运行配置,实现系统安全的自适应控制和管理.给出了该方法应用的具体步骤,并验证了其有效性.     

A SUPER‐AGENT‐BASED FRAMEWORK FOR REPUTATION MANAGEMENT AND COMMUNITY FORMATION IN DECENTRALIZED SYSTEMS

In this article, we propose a novel super‐agent‐based framework for reputation management and community formation in decentralized systems. We describe this framework in the context of Web service selection where agents with more capabilities act as super‐agents. These super‐agents serve as reputation managers to maintain reputation information of services and share the information with other consumer agents that have fewer capabilities than the super‐agents. In addition, super‐agents can maintain communities and build community‐based reputation for a service based on the opinions from all community members that have similar interests and judgement criteria as the super‐agents or the other community members. A practical reward mechanism is also introduced to create incentives for super‐agents to contribute their resources (to maintain reputation and form communities) and provide truthful reputation information. Experimental results obtained through simulation confirm that our approach achieves better effectiveness and scalability compared to the systems that do not use super‐agents and that do not form communities.     

Proactive privacy practices in transition: Toward ubiquitous services

As the Internet paved the way for electronic businesses, ubiquitous services (u-services) will be the next wave launched by electronic services based on current customer information potential. However, privacy is a strategic issue and has been identified as a key hindrance to u-services. As a proactive approach and drawing upon integrative social contracts theory, this study presents a proactive privacy practices framework to examine how the interplays within electronic service, providers’ proactive approaches influence customer disclosure willingness for future u-services, adoption. The results and implications of this study are discussed and expected to shed light on privacy practices.     

Why would online gamers share their innovation-conducive knowledge in the online game user community? Integrating individual motivations and social capital perspectives

The user community has been an important external source of a firm’s product or service innovation. Users’ innovation-conducive knowledge sharing enables the community to work as a vital source of innovation. But, traditional economic theories of innovation seem to provide few explanations about why such knowledge sharing takes place for free in the user community. Therefore, this study investigates what drives community users to freely share their innovation-conducive knowledge, using the theory of planned behavior. Based on an empirical analysis of the data from 1244 members of a South Korean online game user community, it reveals that intrinsic motivation, shared goals, and social trust are salient factors in promoting users’ innovation-conducive knowledge sharing. Extrinsic motivation and social tie, however, were found to affect such sharing adversely, contingent upon whether a user is an innovator or a non-innovator. The study illustrates how social capital, in addition to individual motivations, forms and influences users’ innovation-conducive knowledge sharing in the online gaming context.     

How to foster frontline employee knowledge sharing within service‐oriented enterprises: Empirical evidence from China

Based on the context of Chinese workplace, the present research aims to explore the combined effects of proactive personality, supervisor–subordinate guanxi (s–s guanxi), and leaders’ innovation expectations on the knowledge sharing of frontline employees (FLEs). Questionnaire data from a sample of 301 FLEs within service‐oriented enterprises in China were used in this study. The results show that proactive personality and leaders’ innovation expectations are both positively related to employees’ psychological empowerment and knowledge sharing, and s–s guanxi significantly impacts psychological empowerment, but has a nonsignificant effect on knowledge sharing. This study expands the understanding of FLEs’ knowledge sharing behavior and enriches our understanding of the guanxi construction process during the interaction between supervisors and subordinates.     

基于语义Web技术的上下文感知的智能移动服务

语义Web技术应用于上下文感知的智能移动服务，通过构建上下文信息本体，使得移动服务的实体之间可以进行上下文信息共享和语义互操作，并进行上下文信息推理，实现智能服务。本文首先介绍了语义Web及本体技术，其次阐述了语义Web技术应用于上下文感知的移动服务，然后详细分析了智能移动服务中的上下文信息本体构建，包括通用的上下文信息本体、用户概况本体、情境本体以及服务本体等，接着介绍了相关的研究项目，最后进行展望和总结。     

再多一次接触:顾客反馈机制对服务失败后顾客评价的影响

It is difficult to control service quality for any service firm and service failure is inevitable due to human or non-human factors. As a result, service recovery stirred the interest of researchers and practitioners. However, service failure may not be identified by firms because a majority of dissatisfied customers will not complain to the service provider. Thus, this research proposes a proactive customer feedback mechanism comprised of proactive solicitation of customer feedback, customers providing feedback and follow-up communication and examine their impact of customer evaluations in the context of service failure. This research tries to establish that through adding a continuous series of satisfied service encounters or "moment of truth" to service failure encounters, the customer evaluations (e.g. satisfaction, trust, purchase intent and positive WOM) toward the service will be significantly improved. Our research employed a 2×2×2 between subjects experimental design. Three independent variables were manipulated as presence and absence level, that is, firms either proactively solicitted customer feedback or employed no solicitation of feedback, Customers either provided feedback to the service firm or refused to provide feedback, and service firm either conducted follow-up communication or no follow-up communication. Our research adoptted a scenario in the context of patronizing a three-star hotel on a business trip. In total, 221 business administration graduates from a famous university in Shanghai participated in the experiment. MANOVA was used to test the hypotheses. The results indicated that proactive solicitation significantly influenced trust (p<0.01). Besides satisfaction, the other dependent variables such as trust, purchase intent and positive WOM significantly differred between with and without follow-up communication groups (p<0.05). Third, a significant difference was detected regarding satisfaction, trust, purchase intent and positive WOM between customer providing feedback groups and no customer feedback groups (p<0.05). Moreover, significant interactive effects were found of customers provided feedback and follow-up communication on trust and purchase intent. Trust and purchase intent reached highest when a follow-up communication occurred after customers provided feedback. However, no interactive effects were found of proactive solicitation of customer feedback and customer providing feedback. This research suggests that service providers should create new encounters with customers when they are confronted with service failure, and in this study, through proactive customer feedback mechanism. That is, first, the service provider should encourage customers to provide feedback, which can improve customer evaluations after service failure and after customers providing feedback. At the same time, the firm should employ follow-up communication with the customer and inform them about how the firm responded to their complaints, suggestions and comments. It is worth to note that companies just need to have follow-up communication with those customers who have provided feedback. More important, as information technology and internet prevails, it is very likely sending email and short messages after a service failure to maintain customer relationships could significantly enhance customer evaluations of the service provider. Of course, how consumers respond to such measures online is an promising research area and needs further investigation.     

移动分布式环境下服务适配系统研究

移动环境给分布式资源共享特别是服务发现和资源定位带来了新的挑战。本文分析了移动性给服务发现和资源定位机制带来的特殊性,介绍了具有服务主动适配能力的服务适配原型系统Service CatalogNet,给出了其中的关键技术：适应移动性需求的支持多样性的服务模型、服务主动适配策略以及基于模糊匹配的服务定位机制。     

Investigating information sharing behavior: the mediating roles of the desire to share information in virtual communities

Social networking sites are built and designed to provide online services and a platform for people to social interacts and exchange information. This study used the social capital theory as a foundation to explore the social interaction factors and individual factors such as shared value, community identification, and information privacy concerns, and examine the mediating role of the desire to give information between trust on websites/members and information sharing behaviour in the proposed model. This research sample consists of seven hundred and twenty-seven members who have used the Facebook fan page for at least 6 months. This study adopted structural equation modeling to test the research hypotheses. The results of this study show that shared value, community identification, and information privacy concern directly influence trust on websites and members. Trust on websites and members directly influenced the desire to get/give information. Desire to give information directly influences information sharing behaviour. The desire to give information plays important mediating roles between trust on websites/members and information sharing behaviour. Finally, we provide conclusions and managerial implications of the findings.     

Implementing adaptive mobile GI services based on ontologies: Examples from pedestrian navigation support

As we are facing the dawn of ubiquitous computing (UbiComp) by emerging mobile devices and distributed applications, personalization is leaving the desktop domain, because adaptation and context-awareness play a major role in UbiComp in order to realize the user friendliness postulated for UbiComp applications. Adaptation is a relatively new concept for GI services. Therefore we introduce the related research areas. The two most important factors for adaptation are (a) context as the representation of the current situation and (b) the user itself. In particular how to dynamically derive information on the users’ properties is a research area applying learning strategies introduced shortly. We see these two concepts not isolated but propose an integrated situation model including several types of context as well as user parameters. After this introduction we present several approaches to realizing adaptive mobile GI services in the domain of pedestrian navigation and tourist information – representing first steps towards UbiGIS (www.ubigis.org). These include context and user-aware proactive tips, personalized tour planning and adaptive maps. Implementations and new concepts for extensions of these are presented. The paper closes by an outlook on open research issues related to adaptive GI services.     

An incentive compatible reputation mechanism for ubiquitous computing environments

The vision of ubiquitous computing is becoming a reality thanks to the advent of portable devices and the advances in wireless networking technologies. It aims to facilitate user tasks through seamless utilization of services available in the surrounding environments. In such distributed environments featuring openness, interactions such as service provision and consumption between entities that are unknown or barely known to each other, are commonplace. Trust management through reputation mechanism for facilitating such interactions is recognized as an important element of ubiquitous computing. It is, however, faced by the problems of how to stimulate reputation information sharing and enforce honest recommendation elicitation. We present in this paper an incentive compatible reputation mechanism to facilitate the trustworthiness evaluation of entities in ubiquitous computing environments. It is based on probability theory and supports reputation evolution and propagation. Our reputation mechanism not only shows robustness against lies, but also stimulates honest and active recommendations. The latter is realized by ensuring that active and honest recommenders, compared to inactive or dishonest ones, can obtain the most number of honest (helpful) recommendations and thus suffer the least number of wrong trust decisions, as validated by simulation based evaluation. The proposed reputation mechanism is also implemented as part of a QoS-aware Web service discovery middleware and evaluated regarding its overhead on service discovery latency.     

Adaptive notifications to support knowledge sharing in close-knit virtual communities

Social web-groups where people with common interests and goals communicate, share resources, and construct knowledge, are becoming a major part of today’s organisational practice. Research has shown that appropriate support for effective knowledge sharing tailored to the needs of the community is paramount. This brings a new challenge to user modelling and adaptation, which requires new techniques for gaining sufficient understanding of a virtual community (VC) and identifying areas where the community may need support. The research presented here addresses this challenge presenting a novel computational approach for community-tailored support underpinned by organisational psychology and aimed at facilitating the functioning of the community as a whole (i.e. as an entity). A framework describing how key community processes—transactive memory (TM), shared mental models (SMMs), and cognitive centrality (CCen)—can be utilised to derive knowledge sharing patterns from community log data is described. The framework includes two parts: (i) extraction of a community model that represents the community based on the key processes identified and (ii) identification of knowledge sharing behaviour patterns that are used to generate adaptive notifications. Although the notifications target individual members, they aim to influence individuals’ behaviour in a way that can benefit the functioning of the community as a whole. A validation study has been performed to examine the effect of community-adapted notifications on individual members and on the community as a whole using a close-knit community of researchers sharing references. The study shows that notification messages can improve members’ awareness and perception of how they relate to other members in the community. Interesting observations have been made about the linking between the physical and the VC, and how this may influence members’ awareness and knowledge sharing behaviour. Broader implications for using log data to derive community models based on key community processes and generating community-adapted notifications are discussed.     

基于椭圆曲线密码体制的先应式秘密共享方案

直接使用传统密码学甚至门限密码学提供的方法都不能很好地保证密钥的安全性。而先应式秘密共享方案则能较好地解决这类问题。它是在(t,n)门限密码学密钥共享的基础上,通过周期性地刷新共享份额的值(但不改变共享的密钥)并清除原来的共享份额值,使得攻击者在一个周期中获得的信息在刷新之后变得毫无用处。所以,攻击者要想窃取一个系统的密钥,必须在同一个周期内攻破t个或者t个以上的服务器才可能成功。因此,合理设置门限参数t和时间周期的长短就可以保证密钥的长期安全性。文中设计了一种基于椭圆曲线密码体制的先应式秘密共享方案,包括初始化、份额更新、份额恢复和秘密重构,实现了先应式秘密共享协议的各种算法。     

一种主动秘密共享算法

在电子商务和开放网络中，有一类高度机密且长期有效的密钥需要保护．直接使用传统密码学甚至门限密码学提供的方法都不能很好地保证其安全性．而主动秘密共享方案则能较好地解决这类问题．它是在(t 1，n)-门限密码学密钥共享的基础上，通过周期性地刷新影子的值(但不改变共享的密钥)并清除原来的影子值，使得攻击者在一个周期中获得的信息在刷新之后变得毫无用处．所以，攻击者要想窃取一个系统的密钥，必须在同一个周期内攻破t个以上的服务器才可能成功．因此，合理设置门限参数和时间周期的长短就可以保证密钥的长期安全性．迄今为止，只有一个有缺陷的主动秘密共享算法．在此给出一个针对离散对数密钥的主动共享算法，并完整地证明了其安全性和鲁棒性．     

UbiSrvInt – a context-aware fault-tolerant approach toward wireless P2P service provision

Peer-to-Peer applications harness sharing between free resources (storage, contents, services, human presence, etc.). Most existing wireless P2P applications concern merely the sharing of a variety of contents. For magnifying the sharing extent for wireless service provision in the vicinity (i.e., the wireless P2P environments), this paper presents the UbiSrvInt approach and this is the first attempt to enable a pure P2P solution that is context aware and fault tolerant for ad hoc wireless service provision. This approach empowers an autonomous peer to propel distributed problem solving (e.g., in the travel domain) through service sharing and execution in an intelligent P2P way. This approach of ad hoc wireless service provision is not only highly robust to failure (based on a specific clustering analysis of failure correlation among peers) but also capable of inferring a user’s service needs (through a BDI reasoning mechanism utilizing the surrounding context) in ad hoc wireless environments. We have implemented UbiSrvInt into a system platform with P-JXTA that shows fairly promising performance results on fault tolerance and context awareness.     

基于智能合约的数据共享激励机制研究

随着大数据时代的到来,构建数据共享社区成为一种促进数据收集、流通和使用的新模式,但是在传统社区组织方式下,成员由于互不信任导致不愿共享数据,且共享社区普遍缺乏有效的激励机制,从而限制了数据共享社区的发展。区块链的本质是一个分布式账本,能够提升数据共享的透明性,防止信息滥用,所有存在区块链上的数据可溯源且不可篡改,可以保证数据的归属权,这些都为成员之间的信任打下了基础。在基于区块链的数据共享社区平台上,结合演化博弈理论构建一种数据共享激励模型EGDSI,并通过复制动态力学方程与演化稳定策略分析,得出影响数据共享的关键因素与数据共享激励的3种策略。在此基础上,利用区块链智能合约技术实现安全、高效且动态可调节的数据共享模板引擎。对共享策略影响因素和智能合约激励机制进行仿真分析,结果表明,该数据共享激励机制可以有效促进用户参与数据共享,相较EGI模型,EGDSI模型能够更快地达到数据共享饱和状态。     

Context-based matching for Web service composition

In this paper, we propose a novel matching framework for Web service composition. The framework combines the concepts of Web service, context, and ontology. We adopt a broad definition of context for Web services, encompassing all information needed for enabling interactions between clients and providers. Context-based matching for Web services requires dealing with three major research thrusts: context categorization, modeling, and matching. We first propose an ontology-based categorization of contextual information in Web service environments. We then define a two-level mechanism for modeling Web service contexts. In the first level, service providers create context specifications using category-specific Web service languages and standards. In the second level, context specifications are enveloped by policies (called context policies) using WS-Policy standard. Finally, we present a peer-to-peer architecture for matching context policies. The architecture relies on a context matching engine, context policy assistants, and context community services. Community services implement rule-based techniques for comparing context policies. Recommended by: Zakaria Maamar     

Improving sustainability of BitTorrent darknets

Private BitTorrent community, known as “BitTorrent Darknet” or “Private Tracker (PT)”, has received much attention in the research literature recently. Different from public BitTorrent community, PT can only be accessed by its registered members, and it can provide ultra-high downloading speed due to its effective Sharing Ratio Enforcement (SRE) incentive mechanism which stimulates members to contribute content as much as possible. Although the downloading performance in PTs with high Seeder-to-Leecher Ratio (SLR) is much better than in public BitTorrent communities, our measurements show that SRE mechanism can induce “Poor Downloading Motivation” problem for members who want to increase their sharing ratios to survive and thrive in PT. This problem may discourage PT members’ enthusiasm from contributing to community. To improve sustainability of PTs, we adopt the Predator–prey model to analyze high SLR phenomenon, study the optimal stable SLR range to PTs. Moreover, we develop a queuing model to simulate the seeding/leeching process in a single torrent in PT, and try to maximize the swarming performance with minimum seeding peers. This solution can help PT achieve the optimal SLR range.     

Fostering the determinants of knowledge sharing in professional virtual communities

Professional virtual communities (PVCs), which are formed on the Internet, are expected to serve the needs of members for communication, information, and knowledge sharing. The executives of organizations should consider PVCs as a new innovation or knowledge pool since members share knowledge. However, many PVCs have failed due to members’ low willingness to share knowledge with other members. Thus, there is a need to understand and foster the determinants of members’ knowledge sharing behavior in PVCs. This study develops an integrated model designed to investigate and explain the relationships between contextual factors, personal perceptions of knowledge sharing, knowledge sharing behavior, and community loyalty. Empirical data was collected from three PVCs and tested using structural equation modeling (SEM) to verify the fit of the hypothetical model. The results show that trust significantly influences knowledge sharing self-efficacy, perceived relative advantage and perceived compatibility, which in turn positively affect knowledge sharing behavior. Furthermore, the study finds that the norm of reciprocity does not significantly affect knowledge sharing behavior. The results of the study can be used to identify the motivation underlying individuals’ knowledge sharing behavior in PVCs. By investigating the impacts of contextual factors and personal perceptions on knowledge sharing behavior, the integrated model better explains behavior than other proposed models. This study might help executives of virtual communities and organizations to manage and promote these determinants of knowledge sharing to stimulate members’ willingness to share knowledge and enhance their virtual community loyalty. As only little empirical research has been conducted on the impact of knowledge sharing self-efficacy, perceived relative advantage, and perceived compatibility on the individual’s knowledge sharing behavior in PVCs, the empirical evidence reported here makes a valuable contribution in this highly important area.