Slow Switching Design of Switched Linear Systems

Zhendong Sun 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

In this work, we address the slow switching design problem for a class of switched linear systems. To balance between dwell time and performance, we introduce the concept of E-robust dwell time, and develop aprocedure for computing the largest E-robust dwell time. A new combined switching strategy is developed to furtheren large the dwell time without deteriorating the system performance.

A Hybrid Multiuser Detection Algorithm for Outer Space DS-UWB Ad-hoc Network with Strong Narrowband Interference

( Zhendong Yin ),( Yunsheng Kuang ),( Hongjian Sun ),( Zhilu Wu ),( Wenyan Tang ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.5

Formation flying is an important technology that enables high cost-effective organization of outer space aircrafts. The ad-hoc wireless network based on direct-sequence ultra-wideband (DS-UWB) techniques is seen as an effective means of establishing wireless communication links between aircrafts. In this paper, based on the theory of matched filter and error bits correction, a hybrid detection algorithm is proposed for realizing multiuser detection (MUD) when the DS-UWB technique is used in the ad-hoc wireless network. The matched filter is used to generate a candidate code set which may contain several error bits. The error bits are then recognized and corrected by an novel error-bit corrector, which consists of two steps: code mapping and clustering. In the former step, based on the modified optimum MUD decision function, a novel mapping function is presented that maps the output candidate codes into a feature space for differentiating the right and wrong codes. In the latter step, the codes are clustered into the right and wrong sets by using the K-means clustering approach. Additionally, in order to prevent some right codes being wrongly classified, a sign judgment method is proposed that reduces the bit error rate (BER) of the system. Compared with the traditional detection approaches, e.g., matched filter, minimum mean square error (MMSE) and decorrelation receiver (DEC), the proposed algorithm can considerably improve the BER performance of the system because of its high probability of recognizing wrong codes. Simulation results show that the proposed algorithm can almost achieve the BER performance of the optimum MUD (OMD). Furthermore, compared with OMD, the proposed algorithm has lower computational complexity, and its BER performance is less sensitive to the number of users.

Assessment of across-wind responses for aerodynamic optimization of tall buildings

Zhendong Xu,Jiming Xie 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.21 No.5

A general approach of aerodynamic optimization of tall buildings is presented in this paper, focusing on how to best compromise wind issues with other design aspects in the most efficient manner. The given approach is reinforced by establishing an empirical method that can quickly assess the across-wind loads and accelerations as a function of building frequencies, building dimensions, aspect ratios, depth-to-width ratios, and site exposures. Effects of corner modifications, including chamfered corner and recessed corner, can also be assessed in early design stages. Further, to assess the effectiveness of optimization by tapering, stepping or twisting building elevations, the authors introduce a method that takes use of sectional aerodynamic data derived from a simple wind tunnel pressure testing to estimate reductions on overall wind loads and accelerations for various optimization options, including tapering, stepping, twisting and/or their combinations. The advantage of the method is to considerably reduce the amount of wind tunnel testing efforts and speed up the process in finding the optimized building configurations.

Framework and Key Technology Review of Big Data Analysis in the Social Network Background

Zhendong Ji 보안공학연구지원센터 2016 International Journal of Database Theory and Appli Vol.9 No.6

As the network promoting in people's lives, more and more people use the social networks and other network platform, the concepts of big data have been gradually reference to the network data analysis, researching big data analysis framework and technology can improve enterprise management level. This paper analyzes the framework and its key technology of big data analysis in the context of social network, in order to be able to provide the corresponding theoretical support and reference for analysis of social network data.

Applications Analysis of Big Data Analysis in the Medical Industry

Zhendong Ji 보안공학연구지원센터 2015 International Journal of Database Theory and Appli Vol.8 No.4

With the promoting of big data analysis in every industry, the medical industry is also being widely used big data analysis as the tools, medical industry accumulated a large amount of data because of the wide ranging, it’s has an important role in creating new business value for the medical industry and enhancing healthcare industry by performing the analysis of big data,. This paper focuses on the analysis of big data applications in the medical industry, and discussed the potential of its commercial value for the healthcare industry.

Research On The Relevance Between Mixed-use Complex and User Behaviour Based On Three-dimensional Spatial Analysis

Zhendong Wang,Yihan Pan,Yi Lu,Xihui Zhou Council on Tall Building and Urban Habitat Korea 2023 International journal of high-rise buildings Vol.12 No.1

Under the dual pressure of population growth and land shortage, threedimensional development is the inevitable choice for cities in China. In such a scenario, a mixed-use complex has considerable potential in its realization and research. Based on space syntax and the three-dimensional visibility graph analysis, this paper describes the spatial and functional layout of the Shanghai Super Brand Mall and studies the relationship between spatial visibility and user behaviour through linear regression analysis and correlation analysis. This paper studies three different types of user behaviour, namely, path selection, staying selection, and store selection, and finds that spatial visibility and accessibility have different effects on user behaviour depending on the type and purpose of the activity. This paper reveals the influence of spatial and functional layout on user behaviour and puts forward the corresponding design strategy under the three-dimensional environment.

Model-driven Secure Development Lifecycle

Zhendong Ma,Christian Wagner,Arndt Bonitz,Thomas Bleier,Robert Woitsch,Markus Nichterl 보안공학연구지원센터 2012 International Journal of Security and Its Applicat Vol.6 No.2

Joint Decision and Control Strategy for a Class of Nonhomogeneous Markovian Jump Systems with Input Constraints

Zhendong Wang,Jin Zhu,Wanqing Xie,박준홍 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.5

This paper is concerned with the joint decision and control strategy for a class of nonhomogeneous Markovian jump systems subject to input constraints. By assuming the mode transition rate matrix (MTRM) of Markovian jump systems is piecewise homogeneous instead of homogeneous, a higher-level Markov chain represented by the higher-level mode transition rate matrix (HMTRM) is introduced to describe the variation of MTRM. Based on this, taking into account the minimization of system cost, a novel joint decision and control strategy is proposed in the presence of input constraints. This strategy consists of two sections: decisions are applied to the HMTRM such that the occurrence probability of subsystems is adjusted ultimately; next on the basis of altered HMTRM, controller is designed in view of input constraints. In comparison with conventional control method, this strategy not only guarantees the stability of the considered system well, but also decreases the system cost effectively. Numeral examples along with comparisons are put forward to illustrate the effectiveness of the proposed strategy.

Fault-Tolerant Control of Cascaded H-Bridge Converters Using Double Zero-Sequence Voltage Injection and DC Voltage Optimization

Zhendong Ji,Jianfeng Zhao,Yichao Sun,Xiaojun Yao,Zean Zhu 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.5

Cascaded H-Bridge (CHB) converters can be directly connected to medium-voltage grids without using transformers and they possess the advantages of large capacity and low harmonics. They are significant tools for providing grid connections in large-capacity renewable energy systems. However, the reliability of a grid-connected CHB converter can be seriously influenced by the number of power switching devices that exist in the structure. This paper proposes a fault-tolerant control strategy based on double zero-sequence voltage injection and DC voltage optimization to improve the reliability of star-connected CHB converters after one or more power units have been bypassed. By injecting double zero-sequence voltages into each phase cluster, the DC voltages of the healthy units can be rapidly balanced after the faulty units are bypassed. In addition, optimizing the DC voltage increases the number of faulty units that can be tolerated and improves the reliability of the converter. Simulations and experimental results are shown for a seven-level three-phase CHB converter to validate the efficiency and feasibility of this strategy.

Assessment of across-wind responses for aerodynamic optimization of tall buildings

Xu, Zhendong,Xie, Jiming Techno-Press 2015 Wind and Structures, An International Journal (WAS Vol.21 No.5

A general approach of aerodynamic optimization of tall buildings is presented in this paper, focusing on how to best compromise wind issues with other design aspects in the most efficient manner. The given approach is reinforced by establishing an empirical method that can quickly assess the across-wind loads and accelerations as a function of building frequencies, building dimensions, aspect ratios, depth-to-width ratios, and site exposures. Effects of corner modifications, including chamfered corner and recessed corner, can also be assessed in early design stages. Further, to assess the effectiveness of optimization by tapering, stepping or twisting building elevations, the authors introduce a method that takes use of sectional aerodynamic data derived from a simple wind tunnel pressure testing to estimate reductions on overall wind loads and accelerations for various optimization options, including tapering, stepping, twisting and/or their combinations. The advantage of the method is to considerably reduce the amount of wind tunnel testing efforts and speed up the process in finding the optimized building configurations.