6370123
Full integration of subtyping and if-expression
The combination of full subsumption and conditional expression is a challenging problem, because in such a system, a term might not have a type which is a representative of all types of the term. Therefore, the traditional type checking technique fails. Due to such a difficulty, Java typing rule for if-expression uses only a restricted form of subtyping. In this paper, we propose a type system which includes both of the above mentioned features and enjoys decidable type checking. We also show that the system has the subject reduction property. It is expected that this technique could be used to improve the type system of Java with full subsumption.
1048322
Soundness of Coercion in the Calculus of Constructions
A coercive subtyping system for the Calculus of Constructions is presented. The proposed system λC≤co is obtained essentially by adding coercions and η-conversion to λC≤, which is a subtyping extension to the Calculus of Constructions without coercions. We proved that a coercion c:A ≤ B is semantically sound. That is, (1) c is a term of type A → B; (2) c behaves like an identity function. This development follows the spirit of semantical interpretation of subtyping.
37994970
Image coding quality assessment using fuzzy integrals with a three-component image model
Based on importance measures and fuzzy integrals, a new assessment method for image coding quality is presented in this paper. The proposed assessment is based on two subevaluations. In the first subevaluation, errors on edges, textures, and flat regions are computed individually. The errors are then assessed using an assessment function. A global evaluation with Sugeno fuzzy integral is then obtained based on the importance measure of edge, texture, and flat region. In the second subevaluation, an importance measure is first established depending on the types of regions where errors occur, a subtle evaluation is then obtained using Sugeno fuzzy integral on all pixels of the image. A final evaluation is obtained based on the two subevaluations. Experimental results show that this new image quality assessment closely approximates human subjective tests such as mean opinion score with a high correlation coefficient of 0.963, which is a significant improvement over peak signal-to-noise ratio, picture quality scale, and weighted mean square error, three other image coding quality assessment methods, which have the correlation coefficients of 0.821, 0.875, and 0.716, respectively.
1262783
An Immunity-Based Intrusion Detection Solution for Database Systems
Database intrusion detection has been an important research area in database security. It focuses on malicious transaction attacks, which cannot be handled by traditional database security mechanisms, such as authorization, access control, integrity control, and so on. Although there have appeared some intrusion detection systems, current researches on malicious transaction detection are limited in accuracy and efficiency. Inspired by natural immune system, we propose a novel immunity-based intrusion detection solution for database system in this paper. It provides an additional layer of defense against DBMS misuse, especially malicious transactions. The ability to learn and to adapt to the environment dynamically entitles the system to detect both known and unknown malicious transaction intrusions efficiently. Simulations show that the database intrusion detection system based on data immunity can accelerate detection of malicious transaction attacks and improve its accuracy without causing any other performance penalty.
16819932
A Client Peer Adjustment Policy for Peer-to-Peer Media Streaming
Previous work indicates that more cooperation is needed between peers for peer-to-peer (P2P) media streaming application than files sharing. That implies it is important to select cooperators in P2P networks. However, most of peer selection algorithms are performed at requesting ones and focus on how to choose servers from which clients can benefit more while ignoring whether the scalability and service capacity of systems will be influenced by these results. In this paper, we pay more attention to heterogeneous network capacity of peers and propose a policy fulfilled by server peers to select and adjust clients according to their service capacity and contribution. Peers with higher service capacity may replace existing children. And experiments proved that our policy could improve system's overall utilization and contribution, as well as the depth of multicast tree when compared with delay-based algorithm
7031383
Image retrieval based on Sugeno fuzzy integral
In this paper, we propose a fuzzy similarity measure based on the Sugeno fuzzy integral and apply it to the content-based image retrieval. Fuzzy measure is used to formulate the subjective feedback information. Experimental results show that the proposed method can improve the efficiency and reliability of image retrieval system. Our method of formulating the subjective feedback information performs better than the weighted average operator (WAO) and a Choquet-integral-based similarity measure.
16001718
Fine-Grained Progressive Algorithm Based on HMJ
Wide-area distribution raises significant performance problems for traditional query processing techniques as data access becomes less predictable due to link congestion, load imbalances, and temporary outages. Non-blocking joining query execution is a promising approach to coping with unpredictability in such environments because of reactively scheduling background processing. Classical non-blocking two-way joining technique based on hash-merge (HMJ), however, fail to deliver acceptable performance in such a scenario where relatively short intermittent delay exists in the gross. We have developed a fairly fine-grained hash-merge join, called HMJ-FG, which has employed a replacement selection tree, allowing many disparted segments to be active in parallel. Using the optimization implementation along with simulation obtained by Tao, we show that HMJ-FG is an effective solution for providing fast query responses to users even in the presence of the longer-term of data sources appeared as unavailability. Theory and experimental results show that our technique delivers results significantly fast under unreliable network.