Illinois Institute of Technology

About: Illinois Institute of Technology is a education organization based out in Chicago, Illinois, United States. It is known for research contribution in the topics: Electric power system & Wireless network. The organization has 10188 authors who have published 21062 publications receiving 554178 citations. The organization is also known as: IIT & Illinois Tech.

Privacy-preserving multi-keyword ranked search over encrypted cloud data

Abstract: With the advent of cloud computing, data owners are motivated to outsource their complex data management systems from local sites to the commercial public cloud for great flexibility and economic savings. But for protecting data privacy, sensitive data has to be encrypted before outsourcing, which obsoletes traditional data utilization based on plaintext keyword search. Thus, enabling an encrypted cloud data search service is of paramount importance. Considering the large number of data users and documents in the cloud, it is necessary to allow multiple keywords in the search request and return documents in the order of their relevance to these keywords. Related works on searchable encryption focus on single keyword search or Boolean keyword search, and rarely sort the search results. In this paper, for the first time, we define and solve the challenging problem of privacy-preserving multi-keyword ranked search over encrypted cloud data (MRSE).We establish a set of strict privacy requirements for such a secure cloud data utilization system. Among various multi-keyword semantics, we choose the efficient similarity measure of “coordinate matching”, i.e., as many matches as possible, to capture the relevance of data documents to the search query. We further use “inner product similarity” to quantitatively evaluate such similarity measure. We first propose a basic idea for the MRSE based on secure inner product computation, and then give two significantly improved MRSE schemes to achieve various stringent privacy requirements in two different threat models. Thorough analysis investigating privacy and efficiency guarantees of proposed schemes is given. Experiments on the real-world dataset further show proposed schemes indeed introduce low overhead on computation and communication.

Incorporation of Pr in YBa2Cu3O7−δ: electronic effects on superconductivity

Abstract: Considerable excitement has been generated by the report of superconductivity above 90 K in a multi-phase Y–Ba–Cu oxide1. The superconducting phase was subsequently identified as YBa2Cu3O7−δ2,3. The complete replacement of Y by the trivalent rare-earths La–Lu, with the exception of Ce, Pr and Tb, yields a superconducting phase with a critical temperature (Tc) almost identical to that reported for the yttrium compound4–7. This is somewhat surprising as most of these ions carry significant magnetic moments, the presence of which rapidly decreases Tc in ordinary superconductors. The three exceptions noted, Ce, Pr and Tb, are the rare-earth ions which have a stable tetravalent state. Here we present the results of a study of the structure and transport properties of the series of compounds Y1−xPrxBa2Cu3O7−δ (x = 0−1.0), in which we observe a monotonic decrease in Tc and eventually a metal–nsulator transition with increasing Pr concentration. To date, this is the only rare-earth ion which has been found substantially to alter Tc upon partial substitution for Y.

The area between two item characteristic curves

Abstract: Formulas for computing the exact signed and unsigned areas between two item characteristic curves (ICCs) are presented. It is further shown that when thec parameters are unequal, the area between two ICCs is infinite. The significance of the exact area measures for item bias research is discussed.

Security-Constrained Unit Commitment With Natural Gas Transmission Constraints

Abstract: The contribution of this paper focuses on the development of a security-based methodology for the solution of short-term SCUC when considering the impact of natural gas transmission system. The proposed methodology examines the interdependency of electricity and natural gas in a highly complex transmission system. The natural gas transmission system is modeled as a set of nonlinear equations. The proposed solution applies a decomposition method to separate the natural gas transmission feasibility check subproblem and the power transmission feasibility check subproblem from the hourly unit commitment (UC) in the master problem. Gas contracts are modeled and incorporated in the master UC problem. The natural gas transmission subproblem checks the feasibility of natural gas transmission as well as natural gas transmission security constraints for the commitment and dispatch of gas-fired generating units. If any natural gas transmission violations arise, corresponding energy constraints will be formed and added to the master problem for solving the next iteration of UC. The iterative process will continue until a converged feasible gas transmission solution is found. A six-bus power system with seven-node gas transmission system and the IEEE 118-bus power system with 14-node gas transmission system are analyzed to show the effectiveness of the proposed solution. The proposed model can be used by a vertically integrated utility or the ISO for the short-term commitment and dispatch of generating units with natural gas transmission constraints.