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Sensor Configuration and Test for Fault Diagnoses of Subway Braking System Based on Signed Digraph Method

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Chinese Journal of Mechanical Engineering 2014年第3期27卷 475-482页

作者： zuo Jianyong CHEN Zhongkai Institute of Railway and Urban Mass Transit Tongji University

Fault diagnosis of various systems on rolling stock has drawn the attention of many researchers. However, obtaining an optimized sensor set of these systems, which is a prerequisite for fault diagnosis, remains a major challenge. Available literature suggests that the configuration of sensors in these systems is presently dependent on the knowledge and engineering experiences of designers, which may lead to insufficient or redundant development of various sensors. In this paper, the optimization of sensor sets is addressed by using the signed digraph （SDG） method. The method is modified for use in braking systems by the introduction of an effect-function method to replace the traditional quantitative methods. Two criteria are adopted to evaluate the capability of the sensor sets, namely, observability and resolution. The sensors configuration method of braking system is proposed. It consists of generating bipartite graphs from SDG models and then solving the set cover problem using a greedy algorithm. To demonstrate the improvement, the sensor configuration of the HP2008 braking system is investigated and fault diagnosis on a test bench is performed. The test results show that SDG algorithm can improve single-fault resolution from 6 faults to 10 faults, and with additional four brake cylinder pressure （BCP） sensors it can cover up to 67 double faults which were not considered by traditional fault diagnosis system. SDG methods are suitable for reducing redundant sensors and that the sensor sets thereby obtained are capable of detecting typical faults, such as the failure of a release valve. This study investigates the formal extension of the SDG method to the sensor configuration of braking system, as well as the adaptation supported by the effect-function method.

关键词： fault diagnosis subway braking system signed directed graph sensor set optimization.

Morphology and optical absorption of Bi_2Fe_4O_9 crystals via mineralizer-assisted hydrothermal synthesis

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Particuology 2013年第5期11卷 581-587页

作者： Yi Liu Ruzhong zuo Institute of Electro Ceramics & Devices School of Materials Science and EngineeringHefei University of Technology

Submicron-sized Bi2Fe409 crystals were successfully synthesized via the hydrothermal method, while micron-sized Bi2Fe409 crystals with rod-like morphologies were obtained in the presence of the miner- alizer KN03. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were employed to characterize the products. According to a series of time-dependent experiments, it was con- cluded that the likeliest formation mechanism for the microrods was the Ostwald ripening process. It was proposed that the blocking effect of NO3 contributed to the formation of the rod-like powders. Moreover, the optical absorption of the prepared Bi2Fe409 crystals was measured using an UV-vis spec- trophotometer, indicating that Bi2Fe409 powders can be used as effective photocatalysts under visible light.

关键词： Hydrothermal synthesisCrystal growthBi2Fe409 crystals

AN OPTIMAL DYNAMIC ADVERTISING MODEL WITH INVERSE INVENTORY SENSITIVE DEMAND EFFECT FOR DETERIORATING ITEMS

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Journal of Systems Science and Systems Engineering 2017年第5期26卷 593-608页

作者： Minghui Xu Xiaode zuo School of Management Jinan University Guangzhou 510632 China

This paper proposes a dynamic advertising model for deteriorating items, and the demand is influenced by goodwill and inventory level. The goodwill affected by advertising effort has a positive effect on demand while the inventory level has a negative effect on demand, which is named as inverse inventory sensitive demand effect. We assume that the deteriorating rate could be influenced by the inventory level and we determine the deteriorating rate formulation based on this assumption. The optimal advertising effort and inventory level are obtained by solving the optimization problem based on Pontryagin＇s maximum principle. Furthermore, numerical studies are provided and some managerial insights are presented.

关键词： Dynamic advertising inverse inventory sensitive demand deteriorating items maximumprinciple

Hybrid Local-global Power-sharing Scheme for Droop-free Controlled Microgrids

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维普期刊数据库

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Journal of Modern Power Systems and Clean Energy 2024年第5期12卷 1520-1534页

作者： Kunyu zuo Lei Wu Electrical and Computer Engineering Department Stevens Institute of TechnologyHobokenNJ 07030USA

The droop-free control adopted in microgrids has been designed to cope with global power-sharing goals,i.e.,sharing disturbance mitigation among all controllable assets to even their ***,limited by neighboring communication,the time-consuming peer-to-peer coordination of the droopfree control slows down the nodal convergence to global consensus,reducing the power-sharing efficiency as the number of nodes *** this end,this paper first proposes a local power-sharing droop-free control scheme to contain disturbances within nearby nodes,in order to reduce the number of nodes involved in the coordination and accelerate the convergence speed.A hybrid local-global power-sharing scheme is then put forward to leverage the merits of both schemes,which also enables the autonomous switching between local and global power-sharing modes according to the system *** guidance for key control parameter designs is derived via the optimal control methods,by optimizing the power-sharing distributions at the steady-state consensus as well as along the dynamic trajectory to *** system stability of the hybrid scheme is proved by the eigenvalue analysis and Lyapunov direct ***,simulation results validate that the proposed hybrid local-global power-sharing scheme performs stably against disturbances and achieves the expected control performance in local and global power-sharing modes as well as mode ***,compared with the classical global power-sharing scheme,the proposed scheme presents promising benefits in convergence speed and scalability.

关键词： Droop-free control power-sharing optimal control Lyapunov stability

Particle filter for nonlinear systems with multi-sensor asynchronous random delays

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Journal of Systems Engineering and Electronics 2017年第6期28卷 1064-1071页

作者： Junyi zuo Xiaoping Zhong School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China

This paper is concerned with the recursive filtering problem for a class of discrete-time nonlinear stochastic systems in the presence of multi-sensor measurement delay. The delay occurs in a multi-step and asynchronous manner, and the delay probability of each sensor is assumed to be known or unknown. Firstly, a new model is constructed to describe the measurement process, based on which a new particle filter is developed with the ability to fuse multi-sensor information in the case of known delay *** addition, an online delay probability estimation module is introduced in the particle filtering framework, which leads to another new filter that can be implemented without the prior knowledge of delay probability. More importantly, since there is no complex iterative operation, the resulting filter can be implemented recursively and is suitable for many real-time applications. Simulation results show the effectiveness of the proposed filters.

关键词： particle filter nonlinear dynamic system state estima tion measurement delay multiple sensors

INFLUENCES OF HEAT-TREATING PROCESS ON DUCTILE FRACTURE MECHANISM UNDER MIXED MODE LOADINGS

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中国有色金属学会会刊：英文版 1998年第3期8卷 23-29页

作者： Hong, zuo Fangwen, Wang Xi'an Jiaotong Univ Xi'an China

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１ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｅｎｇｉｎｅｅｒｉｎｇｐｒａｃｔｉｃｅ，ａｌｏｔｏｆｃｒａｃｋｐｒｏｂｌｅｍｓｃａｎｂｅｉｎｃｌｕｄｅｄｉｎｄｉｆｅｒｅｎｔｃｏｍｂｉｎａｔｉｏｎｓｏｆｔｈｒｅｅｂａｓｉｃｆｒａｃｔｕｒｅｍｏｄｅｓ，ｉ．ｅ．ｍｉｘｅｄ...

关键词： mixed mode fracture fracture mechanism shearing yield strain hardening index

Mapping the human brain function in vivo

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Science Bulletin 2016年第24期61卷 1839-1840页

作者： Xi-Nian zuo CAS Key Laboratory of Behavioral Sciences Magnetic Resonance Imaging Research Center Lifespan Connectomics and Behavior Team Institute of Psychology Center for Longevity Research Key Laboratory of Brain and Education Sciences Guangxi Teachers Education University

Mapping of the human brain function in vivo is among the most promising means of uncovering the relationship between brain and behavior. Both the 1000 Functional Connectome Project1 and Human Connectome Project2 have made advancements in the collection, management, and sharing of massive neuroimaging datasets. In China, the government plans to announce the China Brain Project （CBP）, a national brain project aimed at understanding neural mechanisms underlying human cognition with applications of brain disease and brain-inspired computa- tion [1]. Methods for in vivo human brain mapping must be included in the CBP, as they make possible direct assess- ment of brain structure and activity and contribute directly to translational research.

关键词：脑功能活体行为关系功能映射数据共享政府计划神经机制活动过程

Time-like Linear Weingarten Surfaces in Lorentzian Space Forms

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Acta Mathematica Sinica,English Series 2006年第4期22卷 1021-1026页

作者： Da Feng zuo Department of Mathematical Sciences Tsinghua University Beijing 100084 P. R. China Department of Mathematics University of Science and Technology of China Anhui 230026 P. R. China

In this paper we study Backlund transformations of time-like linear Weingarten surfaces with negative discriminant in Lorentzian space forms.

关键词： Time-like linear Weingarten surfaces Backlund transformations Lorentzian space forms

Mixed Elastico-Plasticity Problems with Partially Unknown Boundaries

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Acta Mathematicae Applicatae Sinica 2007年第4期23卷 629-636页

作者： zuo-liang Xu School of Information Renmin University of China Beijing 100872 China

In this paper, we study mixed elastico-plasticity problems in which part of the boundary is known, while the other part of the boundary is unknown and is a free boundary. Under certain conditions, this problem can be transformed into a Riemann-Hilbert boundary value problem for analytic functions and a mixed boundary value problem for complex equations. Using the theory of generalized analytic functions, the solvability of the problem is discussed.

关键词： Mixed elastico-plasticity problems generalized analytic functions unknown boundaries