A Secure Single Sign-On Mechanism for Distributed Computer Networks

User identification is an important access control mechanism for client–server networking architectures. The con-cept of single sign-on can allow legal users to use the unitary token to access different service providers in distributed computer networks. Recently, some user identification schemes have been proposed for distributed computer networks. Unfortunately, most existing schemes cannot preserve user anonymity when possible attacks occur. Also, the additional time-synchronized mechanisms they use may cause extensive overhead costs. To overcome these drawbacks, we propose a secure single sign-on mechanism that is efficient, secure, and suitable for mobile devices in distributed computer networks.

Language : JAVA
Domain    : Data Mining
Contact    : 04652 -402011
Price        : 12,000/-
Email       : contact@nanosoftwares.com

Publishing Search Logs—A Comparative Study of Privacy Guarantees

Search engine companies collect the “database of intentions,” the histories of their users' search queries. These search logs are a gold mine for researchers. Search engine companies, however, are wary of publishing search logs in order not to disclose sensitive information. In this paper, we analyze algorithms for publishing frequent keywords, queries, and clicks of a search log. We first show how methods that achieve variants of k-anonymity are vulnerable to active attacks. We then demonstrate that the stronger guarantee ensured by ε-differential privacy unfortunately does not provide any utility for this problem. We then propose an algorithm ZEALOUS and show how to set its parameters to achieve (ε, δ)-probabilistic privacy. We also contrast our analysis of ZEALOUS with an analysis by Korolova et al. [17] that achieves (ε',δ')-indistinguishability. Our paper concludes with a large experimental study using real applications where we compare ZEALOUS and previous work that achieves k-anonymity in search log publishing. Our results show that ZEALOUS yields comparable utility to k-anonymity while at the same time achieving much stronger privacy guarantees.

Language : Java

Domain    : Data Mining

Contact    : 04652-402011 

Price        : 12,000/- 

Email       : contact@nanosoftwares.com 

EXTENDED XML TREE PATTERN MATCHING: THEORIES AND ALGORITHMS

ABSTRACT

As business and enterprises generate and exchange XML data more often, there is an increasing need for efficient processing of queries on XML data. Searching for the occurrences of a tree pattern query in an XML database is a core operation in XML query processing. Prior works demonstrate that holistic twig pattern matching algorithm is an efficient technique to answer an XML tree pattern with parent-child (P-C) and ancestor-descendant (A-D) relationships, as it can effectively control the size of intermediate results during query processing. However, XML query languages (e.g., XPath and XQuery) define more axes and functions such as negation function, order-based axis, and wildcards. In this paper, we research a large set of XML tree pattern, called extended XML tree pattern, which may include P-C, A-D relationships, negation functions, wildcards, and order restriction. We establish a theoretical framework about “matching cross” which demonstrates the intrinsic reason in the proof of optimality on holistic algorithms. Based on our theorems, we propose a set of novel algorithms to efficiently process three categories of extended XML tree patterns. A set of experimental results on both real-life and synthetic data sets demonstrate the effectiveness and efficiency of our proposed theories and algorithms.


Keywords: Mobile Computing Title, Data Mining Title, Image Processing Title, Networking Title.

THE COQUOS APPROACH TO CONTINUOUS QUERIES IN UNSTRUCTURED OVERLAYS

ABSTRACT

The current peer-to-peer (P2P) content distribution systems are constricted by their simple on-demand content discovery mechanism. The utility of these systems can be greatly enhanced by incorporating two capabilities, namely a mechanism through which peers can register their long term interests with the network so that they can be continuously notified of new data items, and a means for the peers to advertise their contents. Although researchers have proposed a few unstructured overlay-based publish-subscribe systems that provide the above capabilities, most of these systems require intricate indexing and routing schemes, which not only make them highly complex but also render the overlay network less flexible toward transient peers. This paper argues that for many P2P applications, implementing full-fledged publish-subscribe systems is an overkill. For these applications, we study the alternate continuous query paradigm, which is a best-effort service providing the above two capabilities. We present a scalable and effective middleware, called CoQUOS, for supporting continuous queries in unstructured overlay networks. Besides being independent of the overlay topology, CoQUOS preserves the simplicity and flexibility of the unstructured P2P network. Our design of the CoQUOS system is characterized by two novel techniques, namely cluster-resilient random walk algorithm for propagating the queries to various regions of the network and dynamic probability-based query registration scheme to ensure that the registrations are well distributed in the overlay. Further, we also develop effective and efficient schemes for providing resilience to the churn of the P2P network and for ensuring a fair distribution of the notification load among the peers. This paper studies the properties of our algorithms through theoretical analysis. We also report series of experiments evaluating the effectiveness and the costs of the proposed schemes.

Keywords: - Knowledge and Data Engineering Title, Data Mining Title, Cloud Computing Title, Networking Title, wireless Compunctions Title.