503 research outputs found

    Thwarting market specific attacks in cloud

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    Incentive-Centered Design for User-Contributed Content

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    We review incentive-centered design for user-contributed content (UCC) on the Internet. UCC systems, produced (in part) through voluntary contributions made by non-employees, face fundamental incentives problems. In particular, to succeed, users need to be motivated to contribute in the first place ("getting stuff in"). Further, given heterogeneity in content quality and variety, the degree of success will depend on incentives to contribute a desirable mix of quality and variety ("getting \emph{good} stuff in"). Third, because UCC systems generally function as open-access publishing platforms, there is a need to prevent or reduce the amount of negative value (polluting or manipulating) content. The work to date on incentives problems facing UCC is limited and uneven in coverage. Much of the empirical research concerns specific settings and does not provide readily generalizable results. And, although there are well-developed theoretical literatures on, for example, the private provision of public goods (the "getting stuff in" problem), this literature is only applicable to UCC in a limited way because it focuses on contributions of (homogeneous) money, and thus does not address the many problems associated with heterogeneous information content contributions (the "getting \emph{good} stuff in" problem). We believe that our review of the literature has identified more open questions for research than it has pointed to known results.http://deepblue.lib.umich.edu/bitstream/2027.42/100229/1/icd4ucc.pdf7

    Cross-systems Personalisierung

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    The World Wide Web provides access to a wealth of information and services to a huge and heterogeneous user population on a global scale. One important and successful design mechanism in dealing with this diversity of users is to personalize Web sites and services, i.e. to customize system content, characteristics, or appearance with respect to a specific user. Each system independently builds up user proïŹles and uses this information to personalize the service offering. Such isolated approaches have two major drawbacks: firstly, investments of users in personalizing a system either through explicit provision of information or through long and regular use are not transferable to other systems. Secondly, users have little or no control over the information that defines their profile, since user data are deeply buried in personalization engines running on the server side. Cross system personalization (CSP) (Mehta, Niederee, & Stewart, 2005) allows for sharing information across different information systems in a user-centric way and can overcome the aforementioned problems. Information about users, which is originally scattered across multiple systems, is combined to obtain maximum leverage and reuse of information. Our initial approaches to cross system personalization relied on each user having a unified profile which different systems can understand. The unified profile contains facets modeling aspects of a multidimensional user which is stored inside a "Context Passport" that the user carries along in his/her journey across information space. The user’s Context Passport is presented to a system, which can then understand the context in which the user wants to use the system. The basis of ’understanding’ in this approach is of a semantic nature, i.e. the semantics of the facets and dimensions of the uniïŹed proïŹle are known, so that the latter can be aligned with the proïŹles maintained internally at a specific site. The results of the personalization process are then transfered back to the user’s Context Passport via a protocol understood by both parties. The main challenge in this approach is to establish some common and globally accepted vocabulary and to create a standard every system will comply with. Machine Learning techniques provide an alternative approach to enable CSP without the need of accepted semantic standards or ontologies. The key idea is that one can try to learn dependencies between proïŹles maintained within one system and profiles maintained within a second system based on data provided by users who use both systems and who are willing to share their proïŹles across systems – which we assume is in the interest of the user. Here, instead of requiring a common semantic framework, it is only required that a sufficient number of users cross between systems and that there is enough regularity among users that one can learn within a user population, a fact that is commonly exploited in collaborative filtering. In this thesis, we aim to provide a principled approach towards achieving cross system personalization. We describe both semantic and learning approaches, with a stronger emphasis on the learning approach. We also investigate the privacy and scalability aspects of CSP and provide solutions to these problems. Finally, we also explore in detail the aspect of robustness in recommender systems. We motivate several approaches for robustifying collaborative filtering and provide the best performing algorithm for detecting malicious attacks reported so far.Die Personalisierung von Software Systemen ist von stetig zunehmender Bedeutung, insbesondere im Zusammenhang mit Web-Applikationen wie Suchmaschinen, Community-Portalen oder Electronic Commerce Sites, die große, stark diversifizierte Nutzergruppen ansprechen. Da explizite Personalisierung typischerweise mit einem erheblichen zeitlichem Aufwand fĂŒr den Nutzer verbunden ist, greift man in vielen Applikationen auf implizite Techniken zur automatischen Personalisierung zurĂŒck, insbesondere auf Empfehlungssysteme (Recommender Systems), die typischerweise Methoden wie das Collaborative oder Social Filtering verwenden. WĂ€hrend diese Verfahren keine explizite Erzeugung von Benutzerprofilen mittels Beantwortung von Fragen und explizitem Feedback erfordern, ist die QualitĂ€t der impliziten Personalisierung jedoch stark vom verfĂŒgbaren Datenvolumen, etwa Transaktions-, Query- oder Click-Logs, abhĂ€ngig. Ist in diesem Sinne von einem Nutzer wenig bekannt, so können auch keine zuverlĂ€ssigen persönlichen Anpassungen oder Empfehlungen vorgenommen werden. Die vorgelegte Dissertation behandelt die Frage, wie Personalisierung ĂŒber Systemgrenzen hinweg („cross system“) ermöglicht und unterstĂŒtzt werden kann, wobei hauptsĂ€chlich implizite Personalisierungstechniken, aber eingeschrĂ€nkt auch explizite Methodiken wie der semantische Context Passport diskutiert werden. Damit behandelt die Dissertation eine wichtige Forschungs-frage von hoher praktischer Relevanz, die in der neueren wissenschaftlichen Literatur zu diesem Thema nur recht unvollstĂ€ndig und unbefriedigend gelöst wurde. Automatische Empfehlungssysteme unter Verwendung von Techniken des Social Filtering sind etwas seit Mitte der 90er Jahre mit dem Aufkommen der ersten E-Commerce Welle popularisiert orden, insbesondere durch Projekte wie Information Tapistery, Grouplens und Firefly. In den spĂ€ten 90er Jahren und Anfang dieses Jahrzehnts lag der Hauptfokus der Forschungsliteratur dann auf verbesserten statistischen Verfahren und fortgeschrittenen Inferenz-Methodiken, mit deren Hilfe die impliziten Beobachtungen auf konkrete Anpassungs- oder Empfehlungsaktionen abgebildet werden können. In den letzten Jahren sind vor allem Fragen in den Vordergrund gerĂŒckt, wie Personalisierungssysteme besser auf die praktischen Anforderungen bestimmter Applikationen angepasst werden können, wobei es insbesondere um eine geeignete Anpassung und Erweiterung existierender Techniken geht. In diesem Rahmen stellt sich die vorgelegte Arbeit

    Federated Deep Learning for Cyber Security in the Internet of Things: Concepts, Applications, and Experimental Analysis

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    In this article, we present a comprehensive study with an experimental analysis of federated deep learning approaches for cyber security in the Internet of Things (IoT) applications. Specifically, we first provide a review of the federated learning-based security and privacy systems for several types of IoT applications, including, Industrial IoT, Edge Computing, Internet of Drones, Internet of Healthcare Things, Internet of Vehicles, etc. Second, the use of federated learning with blockchain and malware/intrusion detection systems for IoT applications is discussed. Then, we review the vulnerabilities in federated learning-based security and privacy systems. Finally, we provide an experimental analysis of federated deep learning with three deep learning approaches, namely, Recurrent Neural Network (RNN), Convolutional Neural Network (CNN), and Deep Neural Network (DNN). For each deep learning model, we study the performance of centralized and federated learning under three new real IoT traffic datasets, namely, the Bot-IoT dataset, the MQTTset dataset, and the TON_IoT dataset. The goal of this article is to provide important information on federated deep learning approaches with emerging technologies for cyber security. In addition, it demonstrates that federated deep learning approaches outperform the classic/centralized versions of machine learning (non-federated learning) in assuring the privacy of IoT device data and provide the higher accuracy in detecting attacks

    Blockchain-based recommender systems: Applications, challenges and future opportunities

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    Recommender systems have been widely used in different application domains including energy-preservation, e-commerce, healthcare, social media, etc. Such applications require the analysis and mining of massive amounts of various types of user data, including demographics, preferences, social interactions, etc. in order to develop accurate and precise recommender systems. Such datasets often include sensitive information, yet most recommender systems are focusing on the models' accuracy and ignore issues related to security and the users' privacy. Despite the efforts to overcome these problems using different risk reduction techniques, none of them has been completely successful in ensuring cryptographic security and protection of the users' private information. To bridge this gap, the blockchain technology is presented as a promising strategy to promote security and privacy preservation in recommender systems, not only because of its security and privacy salient features, but also due to its resilience, adaptability, fault tolerance and trust characteristics. This paper presents a holistic review of blockchain-based recommender systems covering challenges, open issues and solutions. Accordingly, a well-designed taxonomy is introduced to describe the security and privacy challenges, overview existing frameworks and discuss their applications and benefits when using blockchain before indicating opportunities for future research. 2021 Elsevier Inc.This paper was made possible by National Priorities Research Program (NPRP) grant No. 10-0130-170288 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

    Algorithmic Mechanism Construction bridging Secure Multiparty Computation and Intelligent Reasoning

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    This work presents the construction of intelligent algorithmic mechanism based on multidimensional view of intelligent reasoning, threat analytics, cryptographic solutions and secure multiparty computation. It is basically an attempt of the cross fertilization of distributed AI, algorithmic game theory and cryptography. The mechanism evaluates innate and adaptive system immunity in terms of collective, machine, collaborative, business and security intelligence. It also shows the complexity analysis of the mechanism and experimental results on three test cases: (a) intrusion detection, (b) adaptively secure broadcast and (c) health security

    Macroeconomics and Drug Use: A Review of the Literature and Hypotheses for Future Research

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    Despite more than a century of drug prohibition, problems of addiction and drug abuse continue to be major global public health and criminal justice concerns (United Nations Office on Drugs and Crime, 2015). It has long been obvious that many of these problems are entwined with other economic and social issues. The editors of The Economist, in reporting evidence of a decline in drug use in the UK, speculated on the impact of the concurrent economic slowdown and commented that, "few academics have studied the link between drug use and macroeconomic performance, and what work exists is inconclusive" (Drug use and abuse: The fire next time, 2011). The goal of this paper will be to examine the work that exists on this topic and to propose a set of hypotheses to be tested in future studies

    On the Articulation of Witchcraft and Modes of Production among the Nupe, Northern Nigeria

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    The political economy of occult belief in Africa can highlight hidden social and political conflict in times of transition which remain otherwise undetected. This has been demonstrated in taking the development of witchcraft accusations over time as indicator, and the Nupe of Northern Nigeria as an example. A tentative long-term study on the growth of the Nupe state since pre-colonial times points towards a close relationship between the content and form of witchcraft accusations and the mode of production under which the stakeholders used to life and work. Over time, witchcraft accusations among the Nupe apparently served different, even antagonistic ends, depending on the mode of production in which they were embedded. Much confusion in literature on the apparent contradiction between ‘emancipating’ and ‘oppressive’ functions of witchcraft beliefs could be avoided by considering this articulation between modes of production, witchcraft accusations, and the underlying vested interests of the ruling powers.witchcraft; modes of production; informal politics; social conflict; occult belief; Nupe; Northern Nigeria JEL classification: Z1; Z12

    Recommendations based on social links

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    The goal of this chapter is to give an overview of recent works on the development of social link-based recommender systems and to offer insights on related issues, as well as future directions for research. Among several kinds of social recommendations, this chapter focuses on recommendations, which are based on users’ self-defined (i.e., explicit) social links and suggest items, rather than people of interest. The chapter starts by reviewing the needs for social link-based recommendations and studies that explain the viability of social networks as useful information sources. Following that, the core part of the chapter dissects and examines modern research on social link-based recommendations along several dimensions. It concludes with a discussion of several important issues and future directions for social link-based recommendation research
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