Physical Sciences and Mathematics Commons^™

Direct Optimization Of Ranking Measures For Learning To Rank Models, Li Li Guo

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The main challenge in learning-to-rank for information retrieval is the difficulty to di- rectly optimize ranking measures to automatically construct a ranking model from training data. It is mainly due to the fact that the ranking measures are determined by the order of ranked documents rather than the specific values of ranking model scores, thus they are non-convex, nondifferentiable and discontinuous. To address this issue, listwise approaches have been proposed where loss functions are defined either by exploiting a probabilistic model or by optimizing upper bounds or smoothed approximations of ranking measures. Even though very promising results have been achieved, …

Smart Card Based User Authentication, Brandon James

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User authentication plays a very important role in building a secure computing system. In this thesis, we first studied and investigated existing user authentication schemes and some basic concepts of smart cards. We then proposed and implemented an improved user authentication scheme based on the smart card, specifically, Java card. We simulated a web server, and implemented the user authentication scheme with the Java card by programming a Java card applet and a Java program to send commands and receive responses from the card.

The proposed user authentication scheme has two phases: the registration phase and the user authentication phase. …

Knn-R: Building Secure And Efficient Outsourced Knn Query Service With The Rasp Encryption, Huiqi Xu

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With the wide deployment of public cloud computing infrastructures, outsourcing database services to the cloud has become an appealing solution to save operating expense. However, some databases might be so sensitive or precious that the data owner does not want to move to the cloud unless the security is guaranteed. On the other hand, a secure outsourced service should still provide efficient query processing and significantly reduce the inhouse workload to fully realize the benefits of outsourcing. We summarize these key features for an outsourced service as the CPEL criteria: data Confidentiality, query Privacy, Efficient query processing, and Low inhouse …

Linked Open Data Alignment & Querying, Prateek Jain

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The recent emergence of the "Linked Data" approach for publishing data represents a major step forward in realizing the original vision of a web that can "understand and satisfy the requests of people and machines to use the web content" i.e. the Semantic Web. This new approach has resulted in the Linked Open Data (LOD) Cloud, which includes more than 295 large datasets contributed by experts belonging to diverse communities such as geography, entertainment, and life sciences. However, the current interlinks between datasets in the LOD Cloud, as we will illustrate,are too shallow to realize much of the benefits promised. …