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Chen P.,Jilin University | Wang L.,Jilin University | Wang L.,State Key Laboratory of Computer Science
Journal of Computational Information Systems | Year: 2015

As a new research direction in the field of database security, the technology of multilevel secure database is advancing by leaps and bounds. There are so many great multilevel secure relational models such as Bell-Lapadula model, SeaView model, Jajodia-Sandhu model and Smith-Winslett model in the last 40 years, which have solved or mitigated a lot of problems in this field with their own ways. But each of them still has one or several problems such as covert channels, semantic ambiguity, proliferation of tuples and poor expressiveness for complex situations. In this paper, we attempt to build a new model named TL model which could resolve as many problems as possible independently and retain the simpleness and expressiveness at the same time. We will clarify the TL model and present its simplicity, power and robustness. ©, 2015, Binary Information Press. All right reserved. Source


Ma F.,CAS Institute of Software | Yan J.,CAS Institute of Software | Zhang J.,CAS Institute of Software | Zhang J.,State Key Laboratory of Computer Science
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

In a classical constrained optimization problem, the logical relationship among the constraints is normally the logical conjunction. However, in many real applications, the relationship among the constraints might be more complex. This paper investigates a generalized class of optimization problems whose constraints are connected by various kinds of logical operators in addition to conjunction. Such optimization problems have been rarely studied in literature in contrast to the classical ones. A framework which integrates classical optimization procedures into the DPLL(T) architecture for solving Satisfiability Modulo Theories (SMT) problems is proposed. Two novel techniques for improving the solving efficiency w.r.t. linear arithmetic theory are also presented. Experiments show that the proposed techniques are quite effective. © 2012 Springer-Verlag. Source


Yan R.,State Key Laboratory of Computer Science | Huang K.,Zhejiang University | Yu M.,Zhejiang University | Zhang X.,Zhejiang University
Proceedings - 12th IEEE International Conference on Trust, Security and Privacy in Computing and Communications, TrustCom 2013 | Year: 2013

Automatic multi-threaded code generation is one of the key techniques to improve MPSoC-based programming efficiency. Besides the saving on programming effort, system performance is also an important ant issue to be considered. As thread communication is frequent in multi-threaded code, the whole performance will be improved by reducing communication cost. We present two techniques to improve communication related performance during multi-threaded code generation. One is communication pipeline technique that applies distributed memory server for parallel execution between message passing and functional tasks to reduce the cost caused by communication between different threads. The other technique is to allocate more buffers to communication channel to reduce thread switching. The two techniques can be applied to communicated threads in acyclic topologies. To maximize the application of these techniques, we also propose a technique to search for cyclic techniques and decompose some of the threads to avoid cyclic topologies. © 2013 IEEE. Source


Qiu Z.,Peking University | Qiu Z.,State Key Laboratory of Computer Science | Hong A.,Peking University | Liu Y.,Peking University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

Interface types in OO languages support polymorphism, abstraction and information hiding by separating interfaces from their implementations. The separation enhances modularity of programs, however, it causes also challenges to the formal verification. Here we present a study on interface types, and develop a specification and verification theory based on our former veriJ framework. We support multi-specifications for classes inherited from interfaces and the superclass, and keep the verification modularly without re-touching the verified code. The concepts developed in veriJ, namely the abstract specification and specification predicate, play important roles in this extension, and thus are proved widely useful and very natural in the formal proofs of OO programs. © 2012 Springer-Verlag. Source


Wang L.,Jilin University | Wang L.,State Key Laboratory of Computer Science | Wang S.,Shanghai Lixin University of Commerce | Li X.,Jilin University | Chi B.,Jilin University
Mathematical Problems in Engineering | Year: 2014

Of the numerous proposals to improve the accuracy of naive Bayes (NB) by weakening the conditional independence assumption, averaged one-dependence estimator (AODE) demonstrates remarkable zero-one loss performance. However, indiscriminate superparent attributes will bring both considerable computational cost and negative effect on classification accuracy. In this paper, to extract the most credible dependencies we present a new type of seminaive Bayesian operation, which selects superparent attributes by building maximum weighted spanning tree and removes highly correlated children attributes by functional dependency and canonical cover analysis. Our extensive experimental comparison on UCI data sets shows that this operation efficiently identifies possible superparent attributes at training time and eliminates redundant children attributes at classification time. © 2014 LiMin Wang et al. Source

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