MR Image Segmentation based on Local Information Entropy Geodesic Active Contour Model

Jianwei Zhang,Xiang Ma,Yunjie Chen,Lin Fang,Jin Wang 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.4

Observer-based Non-fragile Mixed Passivity and H∞ Feedback Control for Fuzzy Stochastic Jump System Subject to Quantized Measurements

Kun Ma,Guangming Zhuang,Jianwei Xia,Guoliang Chen,Huasheng Zhang 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.9

This paper considers the topic of the observer-based non-fragile mixed passivity and H∞ state feedback control for time-varying delay and norm-bounded parameter uncertainties fuzzy stochastic Markovian jump system subject to quantized measurements. The aim of this paper is to provide a suitable observer-based non-fragile state feedback controller to enhance stochastic stabilization of the closed-loop system and satisfy mixed passivity and H∞ performance. By constructing mode-dependent Lyapunov-Krasovskii functional, novel conditions are achieved in virtue of linear matrix inequalities. Two examples including truck-trailer model are given to illustrate the effectiveness of the developed method.

The Research of Digital Forensics Technologies under Cloud Computing Environment

Huan Ma,Gaofeng Shen,Ming Chen,Jianwei Zhang 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.3

As the time of cloud computing comes, Cloud computing is estimated to be one of the most transformative technologies in the history of computing. Cloud organizations, including the providers and customers of cloud services, have yet to establish a well-defined forensic capability. Computer cybercrime has become very prominent forms of crime, but the traditional forensic methods have not met the requirements of the new digital forensics environment. In this paper, upon the use of cloud computing resource sharing, storage distribution and other characteristics and based on the analysis of cloud computing environments difficulties on digital forensics, new digital forensics methods and new digital forensics architecture in the cloud-based platform are proposes to meet rapid forensics needs in the era of cloud computing and to deal with the effectiveness, usefulness, depth issues and real-time and reliability problems.

压力性生活事件对大学生学习倦怠的影响: 有调节的中介模型

牛建伟(Jianwei Niu),马学海(Xuehai Ma) YIXIN 출판사 2024 教育教学研究论丛 Vol.2 No.3

探讨压力性生活事对大学生学习倦怠的影响,以及焦虑情绪的中介作用和应对方式的调节作用。研究结果显示,压力性生活事件与积极应对方式成显著负相关,与消极应对方式、焦虑情绪和学习倦怠成显著正相关,积极应对方式与消极应对方式、焦虑情绪和学习倦怠成显著负相关,消极应对方式、焦虑情绪和学习倦怠两两之间成显著正相关;焦虑情绪在压力性生活事件与大学生学习倦怠之间具有显著的中介效应;积极应对方式显著地负向调节压力性生活事件对焦虑情绪和大学生学习倦怠的影响,消极应对方式显著地正向调节压力性生活事件对焦虑情绪和大学生学习倦怠的影响。焦虑情绪在压力性生活事件与大学生学习倦怠之间起中介作用,且这个中介作用受到消极应对方式的调节作用。 To explore the relationship between stressful life events and college students learning burnout, as well as the mediating effect of anxiety and the moderating effect of coping style, this paper conducted a questionnaire survey on 568 college students by using stressful life events scale, learning burnout scale, coping style scale and self-rating anxiety scale. The results show that stressful life events are negatively correlated with positive coping styles, positively correlated with negative coping styles, anxiety and learning burnout, and positively correlated with negative coping styles, anxiety and learning burnout. Anxiety has a significant mediating effect between stressful life events and college students’ learning burnout; Positive coping style significantly negatively regulates the influence of stressful life events on anxiety and learning burnout of college students, while negative coping style significantly positively regulates the influence of stressful life events on anxiety and learning burnout of college students. Anxiety plays an intermediary role between stressful life events and college students’ learning burnout, and this intermediary role is regulated by negative coping styles.

Study on the Prediction of Real estate Price Index based on HHGA-RBF Neural Network Algorithm

Huan Ma,Ming Chen,Jianwei Zhang 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.7

The traditional error of the back-propagation algorithm multilayer feed-forward network (BP neural network), there are the flaws of a slow convergence of forecast, getting local minimum solutions easily, and forecast accuracy rate is not high. This paper proposes a new approach which is the combination of hierarchical genetic algorithm and least squares method to optimize the RBF neural network such that we can predict the real estate price of the Real estate Price Index. And which overcomes the shortcomings of traditional Fourier analysis, has good localized characteristics in the time domain and frequency domain, and has important value. In signal processing, image processing, voice analysis and other fields. The hierarchical genetic algorithm is usually used to optimize the topology of the RBF neural network, the radial basis function center and width. Alternatively, the least squares method could play an important role in deciding the weights of the output layer. The experimental result shows that the feasibility of RBF neural network which could be optimized by the hybrid hierarchical genetic algorithm to predict real estate closing price, and the superiority of this approach in the aspect of prediction accuracy verified in comparing with the other two methods.

Stability analysis of bimodular pin-ended slender rod

Wenjuan Yao,Jianwei Ma,Baolin Hu 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.4

Many novel materials, developed in recent years, have obvious properties with different modulus of elasticity in tension and compression. The ratio of their tensile modulus to compressive modulus is as high as five times. Nowadays, it has become a new trend to study the mechanical properties of these bimodular materials. At the present stage, there are extensive studies related to the strength analysis of bimodular structures, but the investigation of the buckling stability problem of bimodular rods seems to cover new ground. In this article, a semi-analytical method is proposed to acquire the buckling critical load of bimodular slender rod. By introducing non-dimensional parameters, the position of neutral axis of the bimodular rod in the critical state can be determined. Then by combining the phased integration method, the deflection differential equation of bimodular pin-ended slender rod is deduced. In addition, the buckling critical load is obtained by solving this equation. An example, which is conducted by comparing the calculation results between the three of the methods including the laboratory tests, numerical simulation method and the method we developed here, shows that the method proposed in the present work is reliable to use. Furthermore, the influence of bimodular characteristics on the stability is discussed and analyzed.

Regularization Parameter Selection for Total Variation Model Based on Local Spectral Response

Zheng, Yuhui,Ma, Kai,Yu, Qiqiong,Zhang, Jianwei,Wang, Jin Korea Information Processing Society 2017 Journal of information processing systems Vol.13 No.5

In the past decades, various image regularization methods have been introduced. Among them, total variation model has drawn much attention for the reason of its low computational complexity and well-understood mathematical behavior. However, regularization parameter estimation of total variation model is still an open problem. To deal with this problem, a novel adaptive regularization parameter selection scheme is proposed in this paper, by means of using the local spectral response, which has the capability of locally selecting the regularization parameters in a content-aware way and therefore adaptively adjusting the weights between the two terms of the total variation model. Experiment results on simulated and real noisy image show the good performance of our proposed method, in visual improvement and peak signal to noise ratio value.

Nonlinear large deflection buckling analysis of compression rod with different moduli

Wenjuan Yao,Jianwei Ma,Jinling Gao,Yuanzhong Qiu 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.5

Many novel materials exhibit a property of different elastic moduli in tension and compression. One such material is graphene, a wonder material, which has the highest strength yet measured. Investigations on buckling problems for structures with different moduli are scarce. To address this new problem, firstly, the nondimensional expression of the relation between offset of neutral axis and deflection curve is derived based on the phased integration method, and then using the energy method, load-deflection relation of the rod is determined; Secondly, based on the improved constitutive model for different moduli, large deformation finite element formulations are developed and combined with the arc-length method, finite element iterative program for rods with different moduli is established to obtain buckling critical loads; Thirdly, material mechanical properties tests of graphite, which is the raw material of graphene, are performed to measure the tensile and compressive elastic moduli, moreover, buckling tests are also conducted to investigate the buckling behavior of this kind of graphite rod. By comparing the calculation results of the energy method and finite element method with those of laboratory tests, the analytical model and finite element numerical model are demonstrated to be accurate and reliable. The results show that it may lead to unsafe results if the classic theory was still adopted to determine the buckling loads of those rods composed of a material having different moduli. The proposed models could provide a novel approach for further investigation of non-linear mechanical behavior for other structures with different moduli.

Stability analysis of bimodular pin-ended slender rod

Yao, Wenjuan,Ma, Jianwei,Hu, Baolin Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.4

Many novel materials, developed in recent years, have obvious properties with different modulus of elasticity in tension and compression. The ratio of their tensile modulus to compressive modulus is as high as five times. Nowadays, it has become a new trend to study the mechanical properties of these bimodular materials. At the present stage, there are extensive studies related to the strength analysis of bimodular structures, but the investigation of the buckling stability problem of bimodular rods seems to cover new ground. In this article, a semi-analytical method is proposed to acquire the buckling critical load of bimodular slender rod. By introducing non-dimensional parameters, the position of neutral axis of the bimodular rod in the critical state can be determined. Then by combining the phased integration method, the deflection differential equation of bimodular pin-ended slender rod is deduced. In addition, the buckling critical load is obtained by solving this equation. An example, which is conducted by comparing the calculation results between the three of the methods including the laboratory tests, numerical simulation method and the method we developed here, shows that the method proposed in the present work is reliable to use. Furthermore, the influence of bimodular characteristics on the stability is discussed and analyzed.

Fault-tolerant Consensus of Leader-following Multi-agent Systems Based on Distributed Fault Estimation Observer

Pu Yang,Ben Ma,Yan Dong,Jianwei Liu 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.5

This paper is concerned with the fault-tolerant consensus control problem for leader-following multiagent systems with actuator faults and external disturbance. Firstly, by employing the relative output estimation errors with respect to the corresponding neighbours and the leader, a distributed fault estimation observer is constructed for each follower and the established global estimation error system is proven to be asymptotically stable. Secondly, based on the obtained fault estimation, the active fault-tolerant consensus control protocol for each follower is proposed with the utilization of the relative output measurements rather than the state of the systems. Under this control protocol, the actuator faults can be compensated and the influence of disturbance can be eliminated as well. Moreover, it is worth noticing that the process of designing the fault estimation observer and the fault-tolerant controller is separated and their performances are considered simultaneously to simplify the design procedures. Finally, an illustrative example is presented to demonstrate the applicability and the effectiveness of the obtained results.