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Search Results: 1 - 10 of 104474 matches for " Zhang Wenhui "
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Control of Free-floating Space Robotic Manipulators base on Neural Network
Zhang Wenhui
International Journal of Computer Science Issues , 2012,
Abstract: For problems of trajectory tracking of the free-floating space robot model with uncertainties in task space, neural networks adaptive control strategy is put forward by this paper. Because the non-linear system model can not be obtained accurately, neural network is used to directly identify all parts of the system parameters through GL matrix and its multiplication operator ".". Robust controller is designed to eliminate the approximation errors of neural network and external disturbances. The control strategy neither requires an estimate of inverse dynamic model, nor calculates the inverse Jacobin matrix. Global asymptotic stability based on Lyapunov theory is proved by the paper. Simulation results show that higher control precision is achieved. The control strategy has great value in engineering applications.
The Clinical Anatomy of the Cavernous Sinus  [PDF]
Pengfei Zhang, Huanjiu Xi, Wenhui Li
Forensic Medicine and Anatomy Research (FMAR) , 2015, DOI: 10.4236/fmar.2015.32012
Abstract: Introduction: The cavernous sinus (CS) is a very important concept because it is not only interesting to anatomical theory but also useful to clinical medicine, especially in the field of surgery. This paper described the microsurgical anatomy of the CS with special attention to its concept that the CS was really venous sinus or plexus. Materials and Methods: Fifty CSs from 25 Chinese adult cadaver heads fixed in 10% methanal, whose artery and vein were injected with red and blue latex, respectively, dissected stepwise under the operating microscope. Results: Asymmetric and nonintegral blue latex distributed in the cavity of the CS to form a retina with various diameters and repeatedly diverged and converged were observed under the surgical microscope with magnification 5 - 25, after the lateral wall of the CS was opened by maxillary approach. Measurement of sinus included length, diameter and triangular structure of the CS. It is very important to understand the microsurgical anatomy of the CS for neurosurgeons. Conclusion: The CS was venous plexus rather than sinus. The lateral wall of the sinus had two layers, and the lateral cavity of the sinus really did exist even though it was very small. The triangles where maxillary approach passed were more important for neurosurgeons.
UWB Impulse Radio Signal Detection with High-Speed Integrated Comparator
Zhang Wenhui,Lin Jiming
Information Technology Journal , 2008,
Abstract: This study presents an apparatus for detecting Ultra Wide-Band (UWB) impulse radio (IR) signals using circuit with a normal ultra-high-speed integrated comparator, which having nonlinear dynamics characteristics with the same N-shaped I-V characteristic as tunnel diode. This circuit is configured to generate amplified pulse in response to incoming weak UWB impulse radio signals by utilizing the negative resistance region of the I-V characteristic with differential input. It can provide higher symbol rate than correlation detector and is more stable, more feasible and less complicated than the tunnel diode detector. The experiment results indicate that the detecting sensitivity of this apparatus is approximate to that of the tunnel diode detector.
Enhancing the Security of Protocols against Actor Key Compromise Problems
Jing Ma,Wenhui Zhang
Computer Science , 2015,
Abstract: Security of complex systems is an important issue in software engineering. For complex computer systems involving many actors, security protocols are often used for the communication of sensitive data. Actor key compromise (AKC) denotes a situation where the long-term secret key of an actor may be known to an adversary for some reasons. Many protocols are not secure enough for ensuring security in such a situation. In this paper, we further study this problem by looking at potential types of attacks, defining their formal properties and providing solutions to enhance the level of security. As case studies, we analyze the vulnerabilities (with respect to potential AKC attacks) of practical protocols, including PKMv2RSA and Kerberos, and provide solutions to enhance the level of security of such protocols.
A Smart Home System Design Based on GSM  [PDF]
Rongrong Zhang, Xiaoping Zou, Wenhui Huang, Qimu- Surong
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.51B007
Abstract: This paper introduces a mobile phone short message control method in smart home based on GSM (Global System for Mobile communications). AT commands and the system structure is illustrated in detail. The hardware system including STC89C51 and TC35i is presented. The software framework is also analyzed clearly in this paper. In addition, some other potential application areas and its direction of development in future are given at last.
Cooperative Advertising in a Two-Stage Supply Chain with Network Externalities  [PDF]
Wenhui Li
American Journal of Industrial and Business Management (AJIBM) , 2019, DOI: 10.4236/ajibm.2019.94069
Abstract:
A two-stage game is developed with network externalities where, besides pricing decisions, the retailer and manufacturer can determine their advertising investments and advertising participation rates for each stage. In addition to the full cooperation advertising model, three part cooperation advertising models are established. We develop propositions and insights from the comparison of these models. Our main findings are as follows: 1) the equilibrium solutions critically depend on the effects of network externalities; 2) the optimal choice in a two-stage game is to achieve full cooperation; and 3) a second-best choice for the manufacturer is to share the retailer’s advertising in the first stage. Our research results have guiding significance for supply chain member’s decision-making in local advertising practice.
Combining Static Analysis and Case-Based Search Space Partitioning for Reducing Peak Memory in Model Checking
Zhang WenHui,
张文辉

计算机科学技术学报 , 2003,
Abstract:
VERIFICATION OF XYZ/SE PROGRAMS
XYZ/SE程序的验证

Zhang Wenhui,
张文辉

软件学报 , 1995,
Abstract: One of the advantages of XYZ/E is that both high level and low level specifications can be represented in the same frame work, so that it makes specification and implementation of software systems easier. It is important to develop verification tools to verify whether the expected relation between different levels of specifications holds. Rules for verification of XYZ/SE programs had been studied by Xie Hongliang et al. in a previous paper. This paper extends the set of the rules to include rules for use of arrays, for procedure specification and for procedure call. It puts the emphasis on the practical and mechanical aspects of the verification of XYZ/SE programs. A set of rules for simplifying verification conditions is also implemented.
Adaptive Robust Control Free-Floating Space Robotic Manipulators based on RBF Neural Network
Hu Xiaoping,Zhang Wenhui,Ji Xiaoming
International Journal of Computer Science Issues , 2012,
Abstract: Problems of trajectory tracking of the free-floating space robotic manipulators model with uncertainties are studied. An adaptive robust control algorithm of space manipulators based on radial basis function neural network (RBFNN) is proposed by the paper. Neural network controller is used to adaptive learn and compensate the unknown system, approach errors as disturbance are eliminated by robust controller. The weight adaptive laws on-line based on Lyapunov theory can ensure stability of system. The robust controller was proposed based on H theory. Above these assured the stability of the whole system, and L2 gain also was less than the index. This control scheme possesses great control accuracy and dynamic function. The simulation results show that the presented neural network control algorithm is effective.
Diagnostic Value of Transbronchial Lung Biopsy in Peripheral Lung Cancer
Wenhui TANG,Jianguo LI,Wei ZHANG
Chinese Journal of Lung Cancer , 2009,
Abstract: Background and objective Lung cancer is the leading cause of cancer-related death worldwide. Because the locations of peripheral lung cancer are special, diagnosis of peripheral lung cancer is difficult. The aim of this study was to evaluate diagnostic value of transbronchial lung biopsy (TBLB) in peripheral lung cancer. MethodsTransbronchial lung biopsy (TBLB) were performed in 78 cases of peripheral lung cancer which could not be observed by bronchoscope, 42 cases among whom were diagnosed by pathology and cytologic examination. Thirty-six cases of peripheral lung cancer were not able to be diagnosed by TBLB, 22 cases among them were diagnosed by percutaneous lung biopsy (PNLB), and 14 cases being left were diagnosed by surgical operation, lymphadenopathy biopsy, pleura biopsy and sputum cytologic examination successively. Results The positive rate produced by transbronchial lung biopsy, brush biopsy were 53.8% and 8.9% respectively. The total positive rate was 57.7%. The positive rate produced by TBLB was higher than that of brush biopsy (P <0.01). Along with tumor's diameter enlarge, the positive rate of diagnosis was higher. The positive rate of right lung was higher than that of left lung. The positive rate of inferior lung was higher than that of upper lung. The lesions near the inner belt and hilus pulmonis, had the higher positive rate. Complicatin frequency in PNLB was much higher than that in TBLB. Conclusion Transbronchial lung biopsy is an important method in diagnosingof peripheral lung cancer. Combination of TBLB can increase the diagnostic positive rate of peripheral lung cancer.
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