China Information Security Certification Center

Beijing, China

China Information Security Certification Center

Beijing, China

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Yang M.,Beihang University | Li R.,Beihang University | Duan J.,China Information Security Certification Center | Liang L.,China Special Equipment Inspection And Research Institute | And 3 more authors.
NDT and E International | Year: 2013

Spherical fuel elements technology is a main innovation of high-temperature gas-cooled reactors (HTGRs), which effectively improves the safety of the reactors for higher stability at high temperature, and their quality is crucial for the safety and reliability of HTDRs. According to a spherical fuel element's structure, the coated fuel particles are not permitted to enter the fuel-free zone and the elements with escaped fuel particles must be removed during the fuel elements' quality control. In this paper, we first introduce a DR imaging system for spherical fuel elements testing applied in Chinese 10 MW high-temperature gas-cooled reactor (HTR-10). Then the blind zone where escaped particles exist is analyzed under the continuous and concrete circular scanning trajectories and the cone-beam imaging geometrical configuration. The dominant scanning parameters determining the size of the blind zone are the rotation step angle and the distance from X-ray source to the tested object. An optimal method of designing the two parameters to decrease the size of the blind zone is proposed so as to satisfy the testing requirements. Finally, the optimal method is verified by computer simulation and some practical identification results are presented. © 2013 Published by Elsevier Ltd.


Yang M.,Beihang University | Duan S.,Beihang University | Duan J.,China Information Security Certification Center | Wang X.,Beihang University | And 3 more authors.
Journal of X-Ray Science and Technology | Year: 2013

Fast-continuous-rotation is an effective measure to improve the scanning speed and decrease the radiation dose for cone-beam CT. However, because of acceleration and deceleration of the motor, as well as the response lag of the scanning control terminals to the host PC, uneven-distributed and redundant projections are inevitably created, which seriously decrease the quality of the reconstruction images. In this paper, we first analyzed the aspects of the theoretical sequence chart of the fast-continuous-rotation mode. Then, an optimized sequence chart was proposed by extending the rotation angle span to ensure the effective 2π-span projections were situated in the stable rotation stage. In order to match the rotation angle with the projection image accurately, structure similarity (SSIM) index was used as a control parameter for extraction of the effective projection sequence which was exactly the complete projection data for image reconstruction. The experimental results showed that SSIM based method had a high accuracy of projection view locating and was easy to realize. © 2013 IOS Press and the authors.


Tian D.,Beihang University | Guo Z.,Beihang University | Wang Y.,China Information Security Certification Center | Li W.,University of Wollongong | And 4 more authors.
Advanced Functional Materials | Year: 2014

Controllable surface adhesion of solid substrates has aroused great interest both in air and underwater in solving many challenging interfacial science problems such as robust antifouling, oil-repellent, and highly efficient oil/water separation materials. Recently, responsive surface adhesion, especially switchable adhesion, under external stimulus in air has been paid more and more attention in fundamental research and industrial applications. However, phototunable underwater oil adhesion is still a challenge. Here, an approach to realize phototunable underwater oil adhesion on aligned ZnO nanorod array-coated films is reported, via a special switchable contact mode between an unstable liquid/gas/solid tri-phase contact mode and stable liquid/liquid/solid tri-phase contact mode. The photo-induced wettability transition to water and air exists (or does not) in the micro/nanoscale hierarchical structure of the mesh films, playing important role in controlling the underwater oil adhesion behavior. This work is promising in the design of novel interfacial materials and functional devices for practical applications such as photo-induced underwater oil manipulation and release, with loss-free oil droplet transportation. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Gao J.-B.,Nanchang Hangkong University | Gao J.-B.,Shanghai JiaoTong University | Zhang B.-W.,Shanghai JiaoTong University | Chen X.-H.,China Information Security Certification Center
MATEC Web of Conferences | Year: 2015

Quantitative methods for evaluating and managing software security are becoming reliable with the ever increasing vulnerability datasets. The Common Vulnerability Scoring System (CVSS) provides a way to quantitatively evaluate individual vulnerability. However it cannot be applied to evaluate software risk directly and some metrics of CVSS are hard to assess. To overcome these shortcomings, this paper presents a novel method, which combines the CVSS base score with market share and software patches, to quantitatively evaluate the software risk. It is based on CVSS and includes three indicators: Absolute Severity Value (ASV), Relative Severity Value (RSV) and Severity Value Variation Rate (SVVR). Experimental results indicate that by using these indicators, the method can quantitatively describe the risk level of software systems, and thus strengthen software security. © 2015 Owned by the authors, published by EDP Sciences.


Xiao J.,CAS Institute of Automation | Duan J.,China Information Security Certification Center | Yu J.,CAS Institute of Automation
2013 IEEE International Conference on Robotics and Biomimetics, ROBIO 2013 | Year: 2013

This paper deals with the design, construction, and motion control of a jellyfish-inspired swimming robot that uses jet propulsion for thrust generation. The robotic jellyfish consists of a streamlined head, a cavity shell, four separate drive units with bevel gears, as well as an elastic rubber skin around the drive units. In order to replicate the locomotion of jellyfish including a relaxation phase and a contraction phase, four six-bar linkage mechanisms that are centrally symmetric are adopted as the actuators. A triangular wave control algorithm is then proposed to produce desired control signals with an embedded controller. Through independent and coordinated control of the four drive units, the robotic jellyfish is capable of diverse propulsion and maneuvers like swimming forward, turning, and diving/surfacing. Aquatic experiments are further conducted to verify the proposed design and control methods. As a new type of bio-inspired robots, the robotic jellyfish will serve as an effective platform for underwater reconnaissance and environmental monitoring. © 2013 IEEE.


Cai L.-J.,Changchun University of Science and Technology | Cui Z.-H.,China Information Security Certification Center | Liu H.-L.,Astronaus Standards Institute of China
Advanced Materials Research | Year: 2012

In this paper, we propose new distance definitions of fuzzy numbers and analysis their properties. Then the paper draws on several important theorems using these new distance definitions of fuzzy numbers. © (2012) Trans Tech Publications, Switzerland.


Cai L.,Changchun University of Science and Technology | Cui Z.,China Information Security Certification Center | Liu H.,Astronaus Standards Institute of China
IET Conference Publications | Year: 2012

The relationship between the approximation accuracy and the membership functions, the defuzzifier and number of fuzzy rule of T-S fuzzy systems are studied. According to mathematical properties of continuous function, the universal approximation properties of fuzzy mapping in only one interval are analyzed, and some related theorems are proposed and proved. Then, the sufficient conditions of the general T-S fuzzy systems with universal approximation are derived from these theorems, which helps establish the new relationship between approximation error bounds and the number of the fuzzy rules of different T-S fuzzy systems. Finally, the paper proposes some suggestions to construct T-S fuzz systems with universal approximation.


Zhao D.,Beijing University of Chemical Technology | Wang Y.,Beijing University of Chemical Technology | Zhang B.,China Information Security Certification Center
Chinese Control Conference, CCC | Year: 2014

This paper considers the problem of estimating the state and unknown input simultaneously for 2-D Fornasini-Marchesini system with unknown input in both state and measurement equations. The problem is solved by using descriptor system approach and then an asymptotically convergent observer was designed. Two cases, the gain matrix for the unknown input in measurement equation is not and/or is of full column rank, have been discussed. For these two cases, the corresponding sufficient and necessary condition and sufficient condition for the existence of the asymptotical observers are presented and proved in terms of rank condition, respectively. A numerical example is provided to illustrate the convergence properties of the observers and the effectiveness of the proposed method. © 2014 TCCT, CAA.


Wei J.,China Information Security Certification Center | Chen K.,CAS Institute of Software | Lian Y.-F.,CAS Institute of Software | Dai Y.-X.,Chinese Academy of Sciences
2010 International Conference on Machine Learning and Cybernetics, ICMLC 2010 | Year: 2010

A novel edge sampling scheme for IP traceback against DDoS attacks is presented, which is called router's vector edge sampling (RVES). It is simple for marking machines to be implemented. A packet will be probabilistically pre-marked and post-marked on traversed router's interfaces. This approach supports incremental deployment, which makes it effective for multi-path attack reconstruction and computation. Probability packet marking (PPM) and reconstruction algorithm based on RVES is also presented. We implemented prototypes and deployed them in the real Internet to make some experiments. The results show that our method is effective and efficient. © 2010 IEEE.


Gao J.-B.,Tong University | Zhang B.-W.,Tong University | Chen X.-H.,China Information Security Certification Center
Engineering Applications of Artificial Intelligence | Year: 2015

Semantic similarity measuring between words can be applied to many applications, such as Artificial Intelligence, Information Processing, Medical Care and Linguistics. In this paper, we present a new approach for semantic similarity measuring which is based on edge-counting and information content theory. Specifically, the proposed measure nonlinearly transforms the weighted shortest path length between the compared concepts to achieve the semantic similarity results, and the relation between parameters and the correlation value is discussed in detail. Experimental results show that the proposed approach not only achieves high correlation value against human ratings but also has better distribution characteristics of the correlation coefficient compared with several related works in the literature. In addition, the proposed method is computationally efficient due to the simplified ways of weighting the shortest path length between the concept pairs. © 2014 Elsevier Ltd.

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