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Jacobi-Sobolev Orthogonal Polynomialsand Spectral Methods for Elliptic Boundary Value Problems

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Communications on Applied Mathematics and Computation 2019年第2期1卷 283-308页

作者： Xuhong Yu Zhongqing Wang Huiyuan Li University of Shanghai for science and Technology Shanghai 200093China State Key laboratory of Computer science/laboratory of parallel computing Institute of SoftwareChinese Academy of SciencesBeijing 100190China

Generalized Jacobi polynomials with indexes α,β∈ R are introduced and some basic properties are established. As examples of applications,the second- and fourth-order elliptic boundary value problems with Dirichlet or Robin boundary conditions are considered,and the generalized Jacobi spectral schemes are proposed. For the diagonalization of discrete systems,the Jacobi-Sobolev orthogonal basis functions are constructed,which allow the exact solutions and the approximate solutions to be represented in the forms of infinite and truncated Jacobi series. Error estimates are obtained and numerical results are provided to illustrate the effectiveness and the spectral accuracy.

关键词： Generalized Jacobi polynomials Spectral method - Jacobi-Sobolev orthogonal basis functions Elliptic boundary value problems Error analysis

Diffusion and Security Evaluation of Feistel-PG

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Chinese Journal of Electronics 2017年第4期26卷 734-739页

作者： WANG Yanfeng WU Wenling ZHANG Lei Trusted computing and Information Assurance laboratory Institute of Software Graduate University of Chinese Academy of sciences State Key laboratory of Computer science Institute of Software

Feistel-PG structure is a new specific Generalized Feistel structure(GFS) adopted in DBlock and LHash. Its main feature is adding a sbox-size permutation before the round function. Different choices of the permutation may affect the security property of ciphers with Feistel-PG structure but how it effects is not clear. We evaluate the values of diffusion round for all possible parameters and summarize the characteristics of optimum shuffles. The results show that one special kind of FeistelPG achieves full diffusion in less cost than the improved GFS. This advantage may attract the designers’ interests and this kind of Feistel-PG ciphers are suggested to designers. We also evaluate the security of suggested ciphers against various byte-oriented attacks, including differential cryptanalysis, linear cryptanalysis, impossible differential attack and integral attack. Some permutations with optimum diffusion but relatively weaker security are filtered out and these permutations should be avoided by designers.

关键词： Block cipher Diffusion Cryptanalysis GFS Feistel-PG

Social media in Git Hub: the role of @-mention in assisting software development

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science China(Information sciences) 2017年第3期60卷 50-67页

作者： Yang ZHANG Huaimin WANG Gang YIN Tao WANG Yue YU Key laboratory of parallel and Distributed computing College of ComputerNational University of Defense Technology

Recently, many researches propose that social media tools can promote the collaboration among developers, which are beneficial to the software development. Nevertheless, there is little empirical evidence to confirm that using @-mention has indeed a beneficial impact on the issues in Git Hub. In order to begin investigating such claim, we examine data from two large and successful projects hosted on Git Hub, the Ruby on Rails and the Angular JS. By using qualitative and quantitative analysis, we give an in-depth understanding on how @-mention is used in the issues and the role of @-mention in assisting software development. Our statistical results indicate that, @-mention attracts more participants and tends to be used in the difficult issues. @-mention favors the solving process of issues by enlarging the visibility of issues and facilitating the developers' collaboration. Our study also build an @-network based on the @-mention database we *** the @-network, we investigate its evolution over time and prove that we certainly have the potential to mine the relationships and characteristics of developers by exploiting the knowledge from the @-network.

关键词： issues social media @-mention Git Hub software development

A novel anti-detection criterion for covert storage channel threat estimation

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science China(Information sciences) 2018年第4期61卷 212-214页

作者： Chong WANG Changyou ZHANG Bin WU Yu'an TAN Yongji WANG University of Chinese Academy of sciences Cooperative Innovation Center Institute of Software Chinese Academy of Sciences State Key laboratory of Computer science Institute of Software Chinese Academy of Sciences laboratory of parallel software and Computational science Institute of Software Chinese Academy of Sciences

Covert(storage)channels[1]are widely considered a main threat[2]to multilevel secure systems,e.g.,desktop operating *** estimation,as an important part of covert channel analysis,must be included in the security analy... 详细信息

关键词： Linux

ON MAXIMA OF DUAL FUNCTION OF THE CDT SUBPROBLEM

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Journal of Computational Mathematics 2001年第2期19卷 113-124页

作者： Xiong-da Chen Ya-xiang Yuan Reserach Development Center of parallel software Institute of SoftwareBeijing 100080China State Key laboratory of Scientific and Engineering computing Institute of Computational Mathematics and Ssientific/Engineering ComputingAcademy of Mathematics and Systems SciencesChinese Academy of SciencesBeijing 100080China

Focuses on a study which determined the geometry meaning of the maxima of the CDT mathematical subproblem's dual function. Properties of trust region subproblem; Approximation of the CDT feasible region; Relations bet... 详细信息

关键词： trust region subproblem global minimizer approximation

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Large-Scale Multi-Objective Optimization Algorithm Based on Weighted Overlapping Grouping of Decision Variables

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Computer Modeling in Engineering & sciences 2024年第7期140卷 363-383页

作者： Liang Chen Jingbo Zhang Linjie Wu Xingjuan Cai Yubin Xu Shanxi Key laboratory of Big Data Analysis and parallel computing Taiyuan University of Science and TechnologyTaiyuan030024China School of State Key laboratory of Novel software Technology Nanjing UniversityNanjing210008China

The large-scale multi-objective optimization algorithm(LSMOA),based on the grouping of decision variables,is an advanced method for handling high-dimensional decision ***,in practical problems,the interaction among decision variables is intricate,leading to large group sizes and suboptimal optimization effects;hence a large-scale multi-objective optimization algorithm based on weighted overlapping grouping of decision variables(MOEAWOD)is proposed in this ***,the decision variables are perturbed and categorized into convergence and diversity variables;subsequently,the convergence variables are subdivided into groups based on the interactions among different decision *** the size of a group surpasses the set threshold,that group undergoes a process of weighting and overlapping ***,the interaction strength is evaluated based on the interaction frequency and number of objectives among various decision *** decision variable with the highest interaction in the group is identified and disregarded,and the remaining variables are then reclassified into ***,the decision variable with the strongest interaction is added to each *** minimizes the interactivity between different groups and maximizes the interactivity of decision variables within groups,which contributed to the optimized direction of convergence and diversity exploration with different *** was subjected to testing on 18 benchmark large-scale optimization problems,and the experimental results demonstrate the effectiveness of our *** with the other algorithms,our method is still at an advantage.

关键词： Decision variable grouping large-scale multi-objective optimization algorithms weighted overlapping grouping direction-guided evolution

The DBlock family of block ciphers

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science China(Information sciences) 2015年第3期58卷 91-104页

作者： WU WenLing ZHANG Lei YU XiaoLi Trusted computing and Information Assurance laboratory Institute of SoftwareChinese Academy of Sciences State Key laboratory of Computer science Institute of Software Chinese Academy of Sciences

In this paper,we propose a new family of block ciphers named *** consists of three variants which are specified as DBlock-128,DBlock-192,and DBlock-256,***-n has the equal n-bit block length and key *** structure of DBlock successfully combines the advantages of Feistel and Type-2generalized Feistel structures ***,its design of round function employs different linear transforms operating on various word-sizes,which efficiently improve the diffusion *** key schedule of DBlock,it basically employs the same module used in encryption,except the choice of different byte permutations,which can improve its suitability for various implementation environments and also enhance its security against many cryptanalytic *** preliminary evaluation shows that DBlock can achieve enough security margin against known attacks,and it can also obtain excellent performances on various software and hardware platforms.

关键词： block cipher structure round function key scheduling security performance

vSpec: workload-adaptive operating system specialization for virtual machines in cloud computing

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science China(Information sciences) 2016年第9期59卷 47-62页

作者： Xinkui ZHAO Jianwei YIN Zuoning CHEN Sheng HE College of Computer science Zhejiang University National parallel computing Engineering Research Center Jiangnan Institute of computing Technology

In general, operating systems(OSs) are designed to mediate access to device hardware by applications. They process different kinds of system calls using an indiscriminate kernel with the same *** in cloud computing platforms are constructed from service components. Each of the service components is assigned separately to an individual virtual machine(VM), which leads to homogeneous system calls on each VM. In addition, the requirements for kernel function and configuration of system parameters from different VMs are different. Therefore, the suit-to-all design incurs an unnecessary performance overhead and restricts the OS’s processing capacity in cloud computing. In this paper, we propose an adaptive model for cloud computing to resolve the conflict between generality and performance. Our model adaptively specializes the OS of a VM according to the resource-consuming characteristics of workloads on the VM. We implement a prototype of the adaptive model, v Spec. There are five classes of VM: CPU-intensive, memory-intensive, I/O-intensive, networkintensive and compound, according to the resource-consuming characteristics of the workloads running on the VMs. v Spec specializes the OS of a VM according to the VM class. We perform comprehensive experiments to evaluate the effectiveness of v Spec on benchmarks and real-world applications.

关键词： workload classification operating system specialization workload-aware cloud computing v Spec system performance

Universally composable anonymous password authenticated key exchange

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science China(Information sciences) 2017年第5期60卷 153-168页

作者： Xuexian HU Jiang ZHANG Zhenfeng ZHANG Jing XU Trusted computing and Information Assurance laboratory Institute of SoftwareChinese Academy of Sciences State Key laboratory of Mathematical Engineering and Advanced computing science and Technology on Information Assurance laboratory State Key laboratory of Cryptology

Anonymous password authenticated key exchange(APAKE) is an important cryptographic primitive, through which a client holding a password can establish a session key with a server both authentically and anonymously. Although the server is guaranteed that the client in communication is from a pre-determined group, but the client’s actual identity is protected. Because of their convenience, APAKE protocols have been widely studied and applied to the privacy protection research. However, all existing APAKE protocols are handled in stand-alone models and do not adequately settle the problem of protocol composition, which is a practical issue for protocol implementation. In this paper, we overcome this issue by formulating and realizing an ideal functionality for APAKE within the well-known universal composability(UC) framework, which thus guarantees security under the protocol composition operations. Our formulation captures the essential security requirements of APAKE such as off-line dictionary attack resistance, client anonymity and explicit mutual authentication. Moreover, it addresses the arbitrary probabilistic distribution of passwords. The construction of our protocol, which utilizes SPHF-friendly commitments and CCA2-secure encryption schemes, can be instantiated and proven secure in the standard model, i.e., without random oracle heuristics.

关键词： anonymous password authentication key exchange universal composability provable security standard model