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The influence of water reducer on the compressive strength of CRTS II-CA mortar

beijing Gongye Daxue Xuebao/Journal of beijing University of technology 2010年第11期36卷 1482-1487页

作者： Hu, Shu-Guang Li, Yue Xie, Bing Wang, Fa-Zhou Key Laboratory for Silicate Materials Science and Engineering of Ministry of Education Wuhan University of Technology Wuhan 430070 China Key Lab of Urban Security and Disaster Engineering MOE Beijing University of Technology Beijing 100124 China

As the key material used in high-speed railway to reduce vibration in the slab track, CA mortar mainly includes cement, asphalt emulsion and multiple additives. Among all additives, water reducer is the important component. In order to study the influences of water reducer of different types and additions on the strength and micro-structure of CA mortar, three kinds of water reducers of polycarboxylate, naphthalene sulfonate and wood series, were used with different additions to investigate their influences on the strength of CA mortar, meanwhile, the micro-structure were observed by SEM method. The results show that, the polycarboxylate water reducer has the lowest effect to decrease the CA mortar strength. When the types of water reducer are the same, the more the water reducer are, the more the strength decrease. By the SEM observation, the reasons of strength changing of different CA mortars can attributed to the differences of the pore volume, pore size and pore connectivity.

关键词： Scanning electron microscopy

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Nitrite Accumulation During Wastewater Denitrification

Nitrite Accumulation During Wastewater Denitrification

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International Conference on Electrical and Control engineering (ICECE)

作者： Xuezheng Meng Dong Qian Xiangsheng Cao College of Civil Engineering Beijing University of Technology Beijing China Institute of Software Engineering East China Normal University Shanghai China Key Laboratory of Trustworthy Computing of Shanghai East China Normal University Shanghai China Ministry of Education East China Normal University Shanghai China

Characteristics and mechanisms of nitrite accumulation during wastewater denitrification were reviewed based on our experimental results and literatures reports. Nitrite accumulation may be caused by the rate difference between nitrate reduction and nitrite reduction. It can also is the results of some species of bacteria or enzymes absence in the denitrification sludge. Although literature reports were inconsistency, temperature, dissolved oxygen, pH, types of carbon source and C/N ratios are the main environmental factors that have a big influence on nitrite accumulation. Nitrite is detrimental to aquatic organism if the wastewater containing enough nitrite was discharged to waters or can be a big problem for activated sludge process operation. Nitrite accumulated in denitrification may serve as electron donor for anammox reaction and the demonstration tests are undergoing in our lab.

关键词： Carbon Wastewater Microorganisms Kinetic theory Glass Biochemistry Temperature

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Stability Analysis of Continuous-time Iterative Learning Control Systems with Multiple State Delays

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Acta Automatica Sinica 2010年第5期36卷 696-703页

作者： De-Yuan MENG Ying-Min JIA Jun-Ping DU Fa-Shan YU The Seventh Research Division Beihang University (BUAA) Beijing 100083 P. R. China Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia School of Computer Science and Technology Beijing University of Posts and Telecommunications Beijing 100876 P. R. China School of Electrical Engineering and Automation Henan Polytechnic University Jiaozuo 454000 P. R. China

This paper presents a stability analysis of the iterative learning control (ILC) problem for continuous-time systems with multiple state delays, especially when system parameters are subject to polytopic-type uncertainties. Using the two-dimensional (2-D) analysis approach to ILC, the continuous-discrete Roesser's type linear systems are employed to describe the entire learning dynamics of time-delay systems (TDS) with the development of an expanding operator. Based on such Roesser systems, the 2-D system theory is first used to develop a necessary and sufficient condition for the asymptotic stability of ILC, and then the robust H ∞ control theory is combined to provide a sufficient condition in terms of linear matrix inequalities (LMIs) for the monotonic convergence of ILC. It is shown that learning gains can be determined by solving LMIs, which ensure the control input error converges monotonically to zero as a function of iteration. Simulation results show that a robust asymptotically stable ILC scheme can become robustly monotonically convergent by adding the P-type learning gains that satisfy a set of LMIs, which can also improve the convergence rate greatly.

关键词： Iterative learning control (ILC) time-delay systems monotonic convergence 2-D system theory robust H ∞ control theory linear matrix inequality (LMI)

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Kalman filtering with multiple nonlinear-linear mixing state constraints

Kalman filtering with multiple nonlinear-linear mixing state...

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IEEE Conference on Decision and Control

作者： X. Fu Y. Jia J. Du F. Yu Seventh Research Division and the Department of Systems and Control Beihang University Beijing China Beihang University Beijing CN Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia School of Computer Science and Technology Beijing University of Posts and Telecommunications Beijing China School of Electrical Engineering and Automation Henan Polytechnic University Jiaozuo Henan China

This paper is devoted to the problem of state estimation for a class of dynamic system with multiple nonlinear-linear (NL) mixing state constraints. A computational algorithm was developed by C. Yang and E. Blasch to incorporate a positive definite quadratic form equality constraint into the Kalman filtering for the ground vehicle tracking. However, when the target tracked in multidimensional space, a single positive definite quadratic form constraint is not enough due to the involvement of other surface such as hyperboloid, paraboloid, or even plane. A analytic method of incorporating multiple nonlinear-linear mixing state constraints into the Kalman filter is presented here, and a sufficient condition is obtained that guarantee the existence of solution. The constraints may be time varying. At each time step the unconstrained Kalman filter solution is projected onto the state constraints surface. This significantly improves the prediction accuracy of the filter. The use of this algorithm is demonstrated on a nonlinear-linear mixing spacecraft positioning problem.

关键词： Kalman filters Symmetric matrices State estimation Optimization Covariance matrix Noise

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Quick feature selection method and its application on network intrusion detection

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Tongxin Xuebao/Journal on Communications 2010年第9 A期31卷 233-238页

作者： Chen, Tie-Ming Ma, Ji-Xia Xuan, Yi-Guang Cai, Jia-Mei School of Computer Science and Technology Zhejiang University of Technology Hangzhou 310023 China State Key Laboratory of Software Development Environment Beihang University Beijing 100191 China Zhejiang Key Laboratory of Information Security Hangzhou 310012 China

A novel and quick feature selection method, based on data inconsistency was proposed. Due to the different data inconsistency under different pattern generated from different feature subset, the optimal features with no relevant or redundant attribute could be easily found. At last, the intrusion detection benchmark dataset from KDD99 was analyzed into detail to show the superiority of proposed feature selection method, compared with the traditional relevance-based method CFS.

关键词： Intrusion detection

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Comment on Wu et al.'s Server-aided Verification Signature Schemes

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International Journal of Network security 2010年第3期10卷 238-240页

作者： Wang, Zhiwei Wang, Licheng Yang, Yixian Hu, Zhengming Information Security Center State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications No.10 Xi Tucheng Rd. Hai Dian District Beijing 100876 China Key Laboratory of Network and Information Attack and Defence Technology of MOE Beijing University of Posts and Telecommunications No.10 Xi Tucheng Rd. Hai Dian District Beijing 100876 China National Engineering Laboratory for Disaster Backup and Recovery Beijing University of Posts and Telecommunications No.10 Xi Tucheng Rd. Hai Dian District Beijing 100876 China

In ProvSec 2008, Wu et al. constructed two server-aided verification signature (SAV-∑) schemes based on BLS signature. In this paper, we provide a new definition of the security of SAV-∑ against collusion and adaptive chosen message attacks. We founded that Wu et al.'s first scheme is secure, while their second scheme is insecure based on our definition.

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Observer-Based L_(2)-L_(infinity) Control for a Class of Stochastic Systems with Time-Varying Delay

Observer-Based L_(2)-L_(infinity) Control for a Class of Sto...

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2010 49th IEEE Conference on Decision and Control

作者： Lin Li Yingmin Jia Junping Du Fashan Yu Seventh Research Division and the Department of Systems and Control Beihang University (BUAA) Beijing 100191 China Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia School of Computer Science and Technology Beijing University of Posts and Telecommunications Beijing 100876 China School of Electrical Engineering and Automation Henan Polytechnic University Jiaozuo 454000 Henan China

ISBN: (纸本)9781424477456

This paper is devoted to the problem of L_(2)-L_(infinity) control for a class of stochastic time-delay systems via observer-based feedback control. The considered observer contains no time-delay. The purpose is to design an observer-based feedback stabilizing controller such that the augmented closed-loop system is stochastically asymptotically stable with a prescribed L_(2)-L_(infinity) performance satisfied. Based on the stochastic stability theory, a delay-dependent sufficient condition is derived in terms of linear matrix inequalities (LMIs). The observer and controller design method is proposed, while the corresponding explicit expression for the observer and controller gain matrices is also given. Finally, numerical examples and simulation results are included to illustrate the effectiveness of the proposed results.

关键词： stochastic systems system clock time varying stability theory Stochastic delay systems controller gain Closed loop systems

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Model Matching Control for MIMO Systems with Multiple Time Delays and Its Applications in Adaptive Scheme

Model Matching Control for MIMO Systems with Multiple Time D...

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American Control Conference

作者： Haixia Su Yingmin Jia Junping Du Fashan Yu Seventh Research Division and the Department of Systems and Control Beihang University (BUAA) Beijing 100191 China Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia School of Computer Science and Technology Beijing University of Posts and Telecommunications Beijing 100876 China School of Electrical Engineering and Automation Henan Polytechnic University Jiaozuo 454000 Henan China

ISBN: (纸本)9781424474264

This paper considers the model matching problem of multiple-input multiple-output (MIMO) systems with multiple time delays. The reference model is chosen to be the diagonal delay transfer function matrix. A controller is designed for nominal systems. Furthermore, an adaptive control scheme is proposed for uncertain systems with parameter variation. The resulting scheme can guarantee the global stability of the closed-loop systems and the convergence of the tracking errors. A simulation example is included to illustrate the proposed scheme.

关键词： Control system synthesis MIMO Delay effects Programmable control Adaptive control Transfer functions Control systems Uncertain systems Stability Convergence

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Measurements and analysis of stress in soil nails of CNC project

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Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical engineering 2010年第SUPPL. 2期32卷 545-549页

作者： Zhang, Qin-Xi Duan, Yong-Gang Li, Ji-Hong Song, Jing-Yi The Key Laboratory of Urban Security and Disaster Engineering Ministry of Education Beijing University of Technology Beijing 100124 China Beijing Key Lab. of Earthquake Engineering and Structural Retrofit Beijing University of Technology Beijing 100124 China China Railway Construction Group Company Beijing 100040 China

There are ways to evaluate the stress of soil nails, but the actual stress is very different from theoretical analysis. In-situ measurements in CNC project in beijing, mostly adopt the method which lays the reinforcing steel bar-stress measuring apparatus on primary reinforcing steel bar to gain actual pull force when the soil-nailing in working condition. Another method is to contrast the actual pull force with the value calculated by current regulations. The result of the study shows that the stress of soil nails along the length direction appears to be parabola distributing, and the actual pull force in soil nails is no less than 30 kN which is far less than designed stress.

关键词： Soils

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L_(2)-L_(infinity) Filter Design for Neutral Stochastic Time-Delay Systems

L_(2)-L_(infinity) Filter Design for Neutral Stochastic Time...

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2010 49th IEEE Conference on Decision and Control

ISBN: (纸本)9781424477456

This paper is concerned with the problem of L_(2)-L_(infinity) filtering for a class of neutral stochastic systems with both discrete and distributed time-varying delays. The purpose is focusd on the design of a full order filter such that the resulting filtering error system is stochastically asymptotically stable in the mean square with a prescribed L_(2)-L_(infinity) disturbance attenuation level satisfied. By employing Lyapunov functional and stochastic stability theory, a delay-dependent sufficient condition for the existence of such a filter is obtained in terms of linear matrix inequalities (LMIs). The desired filter can be obtained by solving two LMIs.

关键词： Stochastic delay systems Filters mean square filter design stochastic systems error system stability theory Delay systems Filtration

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