Taxonomy of attacks and defense mechanisms in P2P reputation systems—Lessons for reputation system designers

Robust and credible reputation systems are essential for the functionality of Peer-to-Peer (P2P) applications. However, they themselves are susceptible to various types of attacks. Since most current efforts lack an exploration of a comprehensive adversary model, we try to fill in this gap by providing a thorough view of the various credibility threats against a decentralized reputation system and the respective defense mechanisms. Therefore, we explore and classify the types of potential attacks against reputation systems for P2P applications. We also study and classify the defense mechanisms which have been proposed for each type of attack and identify conflicts between defense mechanisms and/or desirable characteristics of credible reputations systems. We finally propose a roadmap for reputation system designers on how to use the results of our survey for the design of robust reputation systems for P2P applications.     

The role of legitimacy and reputation judgments in users’ selection of service providers on sharing economy platforms

Information systems literature suggests that reputation is the main judgment form that captures user-related information online. Drawing on social judgment literature, we contend that a user's online characteristics and past actions are not all reputation-based, but also legitimacy-based, and that transaction stake determines whether users will use reputation or legitimacy judgment to evaluate other users. Using Airbnb, we show that level of stake in a transaction determines the judgment form (reputation or legitimacy) that guests resort to when evaluating a host. Moreover, we find that providing extensive information on a host to potential guests in low-stake transactions is counterproductive.     

IT vendors’ legitimation strategies and market share: The case of EMR systems

This study investigates the legitimation strategies adopted by information technology (IT) vendors and their respective influence on market share. We conducted an analysis of the public discourse on websites of top Electronic Medical Record (EMR) vendors in Ontario, Canada. A total of 815 segments extracted from these websites were analyzed. Our findings indicate that strategies under the cognitive and pragmatic forms of legitimacy were strongly represented in the EMR vendors’ discourses compared with regulative and normative strategies. Furthermore, the link between legitimation strategies and market share has not yet been clearly established. Implications for practice and research are discussed.     

Exploiting users’ social relations to forward data in opportunistic networks: The HiBOp solution

Opportunistic networks, in which nodes opportunistically exploit any pair-wise contact to identify next hops towards the destination, are one of the most interesting technologies to support the pervasive networking vision. Opportunistic networks allow content sharing between mobile users without requiring any pre-existing Internet infrastructure, and tolerate partitions, long disconnections, and topology instability in general. In this paper we propose a context-aware framework for routing and forwarding in opportunistic networks. The framework is general, and able to host various flavors of context-aware routing. In this work we also present a particular protocol, HiBOp, which, by exploiting the framework, learns and represents through context information, the users’ behavior and their social relations, and uses this knowledge to drive the forwarding process. The comparison of HiBOp with reference to alternative solutions shows that a context-aware approach based on users’ social relations turns out to be a very efficient solution for forwarding in opportunistic networks. We show performance improvements over the reference solutions both in terms of resource utilization and in terms of user perceived QoS.     

Input–output operability of control systems: The steady-state case

For high-dimensional systems with more outputs than inputs, some outputs must be controlled within ranges, instead of at set-points. This may also be true if the outputs are equal in number to the inputs and disturbances of high magnitude exist. A linear programming framework is postulated to calculate the tightest achievable operating ranges of the outputs, given the ranges of the inputs and the expected disturbances, for any linear input–output control system at the steady-state. This approach removes the computational constraints on the size of the problem that a previous communication of the authors [1] could address. The hyper-volume obtained for the tightest achievable outputs’ region of a high-dimensional industrial process is calculated to be four orders of magnitude smaller than the one initially assumed, enabling much tighter control.     

Valuation of online social networks taking into account users’ interconnectedness

Online social networks have been gaining increasing economic importance in light of the rising number of their users. Numerous recent acquisitions priced at enormous amounts have illustrated this development and revealed the need for adequate business valuation models. The value of an online social network is largely determined by the value of its users, the relationships between these users, and the resulting network effects. Therefore, the interconnectedness of a user within the network has to be considered explicitly to get a reasonable estimate for its economic value. Established standard business valuation models, however, do not account for these aspects sufficiently. Thus, we propose an economic model for the valuation of online social networks, which takes into account the users’ interconnectedness within the network. Furthermore, we analyze different centrality measures, which can be used to quantify users’ interconnectedness in online social networks and propose a measure which is based on the PageRank-algorithm. Finally, the practical application of the model is illustrated by an example of the European online social network XING.com.     

A dynamic framework for integrated management of all types of resources in P2P systems

Traditional Peer-to-Peer (P2P) systems were restricted to sharing of files on the Internet. Although some of the more recent P2P distributed systems have tried to support transparent sharing of other types of resources, like computer processing power, but none allow and support sharing of all types of resources available on the Internet. This is mainly because the resource management part of P2P systems are custom designed in support of specific features of only one type of resource, making simultaneous access to all types of resources impractical. Another shortcoming of existing P2P systems is that they follow a client/server model of resource sharing that makes them structurally constrained and dependent on dedicated servers (resource managers). Clients must get permission from a limited number of servers to share or access resources, and resource management mechanisms run on these servers. Because resource management by servers is not dynamically reconfigurable, such P2P systems are not scalable to the ever growing extent of Internet. We present an integrated framework for sharing of all types of resources in P2P systems by using a dynamic structure for managing four basic types of resources, namely process, file, memory, and I/O, in the same way they are routinely managed by operating systems. The proposed framework allows P2P systems to use dynamically reconfigurable resource management mechanisms where each machine in the P2P system can at the same time serve both as a server and as a client. The pattern of requests for shared resources at a given time identifies which machines are currently servers and which ones are currently clients. The client server pattern changes with changes in the pattern of requests for distributed resources. Scalable P2P systems with dynamically reconfigurable structures can thus be built using our proposed resource management mechanisms. This dynamic structure also allows for the interoperability of different P2P systems.     

The influence of multimedia training on users’ attitudes: lessons learned

The workforce within the US is increasingly culturally diverse and mobile. Rapid technological changes, coupled with cultural diversity and employee mobility, have created the milieu for critical issues in organizational training methods. Effective learning systems enable employees to adapt more easily to change, thereby increasing their effectiveness. Multimedia systems can be the solution to enhancing performance effectively and efficiently by accelerated learning. This paper examines such a system developed by Holiday Inn Worldwide for the implementation of a new information system. Individuals’ performance and attitudes were tracked for two primary groups: those receiving training on a new information system using traditional training methods and those using a multimedia CDROM to acquire mastery of the same system. 826 employees participated, 467 of them were trained by the multimedia system. Attitude measures included attitudes toward self: job, training, and technology. Individual performance was measured by standardized tests on employees’ knowledge of the new information system. Our findings demonstrated that users’ attitudes were consistently poorer when trained at sites which employed multimedia training when compared with users trained in using a more traditional approach.     

Measurement-based study on the relation between users’ watching behavior and network sharing in P2P VoD systems

P2P-based Video on Demand (P2P VoD) systems can provide higher quality video services than P2P live systems. However, owing to the unavailability of open source codes, the characteristics of P2P VoD systems have not been fully explored. For this purpose, in this paper, we first implemented reverse engineering to the protocols of two most popular VoD systems used in China. Peers’ watching behavior and network sharing were then studied through the measured buffer messages. Based on our study, we found that uploading-only peers were more than downloading peers, and smooth-watching peers were more than randomly-seeking peers in the current P2P VoD systems. This finding is significantly different from the existing P2P-based file dissemination systems and the results obtained in the previous work on VoD systems. Furthermore, this study revealed the relations between watching behavior and network sharing. It has been observed that randomly-seeking peers will provide more regular as well as rare chunks than smooth-watching peers. A simple mathematical model was established to analytically demonstrate the relation between the watching index (WI) distribution and network-sharing profile, and this relation was also validated by our measured data.     

The “problem” in and of management information systems

Management Information Systems uncritically draws upon a number of disciplines for its theoretical framework. In doing so it has imported a host of ontological, epistemological and behavioral assumptions which have shaped the theories, technologies and practices of information system analysis, design and implementation. This has taken place without careful reflection upon the historical emergence of these assumptions or upon the context within which attempts are made to operationalize them. This paper argues that the Management Information Systems field is in need of researching itself. It proposes that through a combination of genealogical and ethnographic research methodologies, the historical emergence of theoretical constructs and the organizational context within which information systems operate should be critically examined. In the following analysis, the historical emergence of the “problem” as a generic construct in the Management Information System literature is examined and contrasted to the manner in which a group of manufacturing managers defined problems within their organizational context. A critical tension is revealed which suggests that information systems researchers, analysts and designers need to at least broaden their assumption about the nature of organizational reality, human behavior, information processing and problem solving.     

Adaptive L_2 control of nonlinear systems using neural networks

An adaptive neural network controller is developed to achieve output-tracking of a class of nonlinear systems. The global L2 stability of the closed-loop system is established. The proposed control design overcomes the limitation of the conventional adaptive neural control design where the modeling error brought by neural networks is assumed to be bounded over a compact set. Moreover,the generalized matching conditions are also relaxed in the proposed L2 control design as the gains for the external disturbances entering the system are allowed to have unknown upper bounds.     

Adaptive L2 control of nonlinear systems using neural networks

An adaptive neural network controller is developed to achieve output-tracking of a class of nonlinear systems. The global L2 stability of the closed-loop system is established. The proposed control design overcomes the limitation of the conventional adaptive neural control design where the modeling error brought by neural networks is assumed to be bounded over a compact set.Moreover,the generalized matching conditions are also relaxed in the proposed L2 control design as the gains for the external disturbances entering the system are allowed to have unknown upper bounds.     

Predicting the influence of users’ posted information for eWOM advertising in social networks

Many social network websites have been aggressively exploring innovative electronic word-of-mouth (eWOM) advertising strategies using information shared by users, such as posts and product reviews. For example, Facebook offers a service allowing marketers to utilize users’ posts to automatically generate advertisements. The effectiveness of this practice depends on the ability to accurately predict a post’s influence on its readers. For an advertising strategy of this nature, the influence of a post is determined jointly by the features of the post, such as contents and time of creation, and the features of the author of the post. We propose two models for predicting the influence of a post using both sources of influence, post- and author-related features, as predictors. An empirical evaluation shows that the proposed predictive features improve prediction accuracy, and the models are effective in predicting the influence score.     

A study on key strategies in P2P file sharing systems and ISPs�� P2P traffic management

The flourish of P2P systems draws a lot of attention of networking researchers. Some research efforts focus on P2P systems, trying to understand the mechanism of various implementations and the behavior pattern of P2P users, and then improve the systems?? performance. Others look at the issue from the angle of ISPs, trying to help ISPs solve various issues brought by P2P applications. In this article, we conduct a review study on recent research efforts in these two areas. The first part of this article focuses on several key strategies that have significant influence on the performance of P2P systems. In the second part, we review some important techniques for ISPs to manage P2P traffic, i.e., blocking, caching and localization, and compare their advantages and disadvantages.     

How does justice matter in online retailers’ reputation and purchase intentions: an empirical study of China

In recent years, online shopping has been proliferated around the world. Online retailers’ reputation and purchase intentions are critical for survival and profitability of any online store. Thus, this study proposes a research framework to examine the perceived justice effects on customers purchase intention and online retailers’ reputation. A confirmatory factor analysis was conducted to demonstrate the reliability and validity of the measurement model, and the structural equation modelling technique was used to test the research model. The hypothesised model was validated empirically using data collected from 383 online shopping customers in China. The results indicated that perceived procedural, distributive and interactional justice components were strong predictors of customers purchase intention and online retailers’ reputation while online retailers’ reputation had significant effects on purchase intentions. Finally, theoretical and managerial implications are also presented in the paper.     

The impact of psychological climate on employees’ innovative use of information systems: The moderating role of goal orientation

The objectives of this study are to investigate climates that could facilitate innovative use of information systems (IS), and to examine how psychological climate and individual goal orientation interact to promote employees’ innovative IS use. A total of 174 questionnaires were collected from enterprise resource planning (ERP) users from nine firms in China. Hierarchical regression analysis was used to test the research hypotheses. The empirical results suggest that (1) psychological climates (psychological autonomy climate and psychological innovation climate) are positively associated with IS users’ innovative use, (2) avoidance orientation weakens the relationship between psychological autonomy climate and innovative use, (3) learning orientation weakens the relationship between psychological innovation climate and innovative use, and (4) learning orientation strengthens the relationship between psychological autonomy climate and innovative use. This study contributes to IS literature by identifying psychological climate as a critical antecedent of innovative use. The findings also fulfil an identified need for more empirical studies of the combined effect of individual and environmental factors on employees’ innovative behaviour in the workplace, especially in the context of IS innovation.     

Understanding Chinese users’ continuance intention toward online social networks: an integrative theoretical model

This study explores users’ continuance intention in online social networks by synthesizing Bhattacherjee’s IS continuance theory with flow theory, social capital theory, and the unified theory of acceptance and use of technology (UTAUT) to consider the special hedonic, social and utilitarian factors in the online social network environment. The integrated model was empirically tested with 320 online social network users in China. The results indicated that continuance intention was explained substantially by all hypothesized antecedents including perceived enjoyment, perceived usefulness, usage satisfaction, effort expectancy, social influence, tie strength, shared norms and trust. Based on the research findings, we offer discussions of both theoretical and practical implications.     

The predictors of users’ satisfaction in an anonymous environment: the role of the negative true self

ABSTRACT

The anonymity of cyberspace enables people to express themselves more freely than in the physical world. Thus, when interacting with others online, some people choose to reconstruct a virtual identity that is partly or even totally different from their physical identity. Using the advanced self-discrepancy theory and the framework of psychological well-being, the current study theoretically modelled the expression of three domains of the self (the ought self, the ideal self and the negative true self) that affects the fulfilment of autonomy and self-acceptance, further influencing people’s overall satisfaction in an anonymous online environment. The data (n?=?837) were collected from QQ, an anonymous social networking platform from China. The results suggested that virtual identity reconstruction in the online world was significantly associated with the fulfilment of autonomy and self-acceptance. Additionally, autonomy and self-acceptance played important roles in shaping user satisfaction.