Changsha University

Changsha, China

Changsha University

Changsha, China
SEARCH FILTERS
Time filter
Source Type

Pan Z.,Changsha University
Proceedings - 2016 International Conference on Smart City and Systems Engineering, ICSCSE 2016 | Year: 2016

In this paper, we focus on the problem of Urban vegetation type analysis, which is a key problem in Urban construction. Firstly, our proposed Urban vegetation type classification system is made up of three parts: 1) Image pre-procesing, 2) Feature space mapping, and 3) Classification. Secondly, in order to tackle the feature space mapping problem, we exploit the Kernel-based Principal Component Analysis (KPCA) technology, which means a nonlinear feature extraction approach. Moreover, KPCA can map the data from the original input space into a higher dimensional feature space with a nonlinear map function. Thirdly, we choose the Gaussian radial basis function as the kernel for KPCA, and then build up the feature vectors of high resolution satellite images. Fourthly, the Urban vegetation type is analyzed based on the support vector machine. Finally, experimental results show that the proposed method can significantly improve the Urban vegetation type classification accuracy. © 2016 IEEE.


At present, the problems existing in the teaching and learning of physical education and health in kindergartens are gradually being paid attention to. After comparing children's learning goals in sports and health from the perspective of action development in our country and the developed countries such as the United States and Germany, through the establishment of model, developing children's flexibilities, strengths and sensitivities was taken as the focus of the training object, and children were divided into control group and experimental group to be compared. The experiment proves that it is helpful for children's physical training to carry out the target development training, which can provide references for the development of children's movements and physical health in our country.


He H.-J.,Changsha University
Dianzi Keji Daxue Xuebao/Journal of the University of Electronic Science and Technology of China | Year: 2017

Spectrum-based fault localization (SBFL) has been proven to be the promising technique during software debugging. SBFL combined various factors in the execution profile to form different fault localization models. However, these models are still agnostic to the particular program and dataset. In this paper we propose a learning to rank method referred to as LTR-sbfl which automatically constructs the SBFL model for each program. Like the existing SBFL methods, we first collect program execution traces and results of test cases. Next, it is directly mapped from the coverage difference in a pair of faulty statement and non-faulty statement to an instance in supervised learning. Finally, the conventional classification algorithm is applied to learn a ranking model for a program based on the training data. The proposed method on three benchmark datasets is evaluated through experiment. Results show that LTR-sbfl can outperform other SBFL approaches in the precision of fault localization. © 2017, Editorial Board of Journal of the University of Electronic Science and Technology of China. All right reserved.


Peng Y.,Changsha University
OPSEARCH | Year: 2017

In this paper, we establish a performance model of a cell in a cellular mobile wireless network with two types of calls arrivals: originating calls and handoff calls. Using the Markovian Arrival Processes to describe the calls arrival processes and PH type distributions to model the calls service times and the cell-sojourn times of any ongoing calls, we investigate the impact of retrial and nonpersistent phenomenon on the performance measures of the system. The algorithms for calculating the stationary state probabilities of the model and determining the optimal number of guard channels and total channels are elaborated. Main performance measures are obtained. Finally, we provide numerical results to illustrate the optimization problems and the impact of retrial and nonpersistent phenomena on performance measures. We find that the performance measures are mainly affected by the two types of calls’ arrivals and service patterns, but the retrial rate plays a little crucial role. © 2017, Operational Research Society of India.


Xu D.,Wuhan University of Technology | Xu D.,Changsha University | Cheng B.,Wuhan University of Technology | Cao S.,Wuhan University of Technology | Yu J.,Wuhan University of Technology
Applied Catalysis B: Environmental | Year: 2015

Silver chromate-graphene oxide (Ag2CrO4-GO) composites are prepared by a facile precipitation method. The resulting Ag2CrO4-GO composites exhibit excellent photocatalytic activity and stability towards the degradation of the dyes and phenol in aqueous solution under visible-light irradiation. The optimal composite with 1.0wt% GO content shows the highest photocatalytic activity for methylene blue (MB) degradation, which is 3.5 times that of pure Ag2CrO4 particles. The enhanced photocatalytic activity is mainly attributed to the formation of Ag2CrO4-GO Z-scheme heterojunction that can not only facilitate the separation and transfer of the photogenerated charge carriers, but also preserve a strong oxidation and reduction ability. The high photocatalytic stability is due to the successful inhibition of the photocorrosion of Ag2CrO4 by transferring the photogenerated electrons of Ag2CrO4 to GO. The present work provides a new understanding into design and fabrication of the GO/silver compound composite photocatalysts. © 2014 Elsevier B.V.


Yang R.,Changsha University | He Y.,National University of Defense Technology
Applied Physics Letters | Year: 2015

Anisotropy and inhomogeneity of carbon fiber reinforced polymers (CFRPs) result in that many traditional non-destructive inspection techniques are inapplicable on the delamination evaluation. This letter introduces eddy current pulsed phase thermography (ECPPT) for CFRPs evaluation considering volumetric induction heating due to small electrical conductivity, abnormal thermal wave propagation, and Fourier analysis. The proposed methods were verified through experimental studies under transmission and reflection modes. Using ECPPT, the influence of the non-uniform heating effect and carbon fiber structures can be suppressed, and then delamination detectability can be improved dramatically over eddy current pulsed thermography. © 2015 AIP Publishing LLC.


Mo H.,Changsha University of Science and Technology | Mo H.,Changsha University
Zidonghua Xuebao/Acta Automatica Sinica | Year: 2012

In order to describe the fuzzy set whose intention varies with time interval, we present the theory of time-varying universe of discourse and dynamic fuzzy rules by synthesizing fuzzy set, linguistic dynamic systems (LDS), and dynamic programming. The time-varying universe discourse is divided into two types: discrete type and continuous type, and each type is sorted into incremental, decremental, and mixed classes. Then, how to build dynamic fuzzy rules and how to compute with words on time-varying universe of discourse are discussed. Finally, the linguistic dynamic orbits on the time-varying universe of discourse are given. Copyright © 2012 Acta Automatica Sinica. All rights reserved.


Sheng W.,Changsha University | Bao Y.,Changsha University
Nonlinear Dynamics | Year: 2013

By adding an electronic throttle and a torque sensor to an engine, it is potentially possible to improve emissions and fuel economy while preserving the torque response of a conventional engine. To do so effectively, however, requires the use of proper control strategy for electronic throttle. In this paper, a kind of fractional order fuzzy PID controller is proposed and it is applied to an electronic throttle. An efficient way to tune fractional order fuzzy PID controller parameters is proposed using a fruit fly optimization algorithm (FOA), which treats the controller parameters tuning as an optimization problem with a proper fitness function. The obtained simulation results show the effective performance of the proposed method. © 2013 Springer Science+Business Media Dordrecht.


Zhu Y.,Changsha University
Advances in Information Sciences and Service Sciences | Year: 2011

Peer-to-Peer (P2P) network has become an essential transmission model for information dissemination and file sharing over the Internet. In this paper, we propose an information security scheme based on JXTA protocol, called XMLP2P. The scheme achieves the aim of hiding secret information in JXTA by modifying the XML documents. In addition, we use secret information dispersal algorithm to complete sensitive data transmission. Security analysis shows our secret scheme is effective in P2P environment.


Li Z.,Changsha University | Li J.,Changsha University
Current Organic Chemistry | Year: 2013

Dendrimers are highly branched macromolecules with well-defined molecular structures and nanometer-scale dimensions. Dendrimer-supported catalysts behave homogeneously during the reaction, but most of them can be separated from the reaction medium via solvent precipitation. Their catalytic properties can be fine-tuned by adjusting the structure, size and shape of the dendrimers. In many cases, interesting dendrimer effects were observed, including increased or decreased the catalytic activity, stability and enantioselectivity. This review focuses on the recent decade of progress concerning the dendrimer-supported catalysts in the following reactions: (a) asymmetric hydrogenation and hydrosilylation; (b) asymmetric transfer hydrogenation; (c) carbon-carbon bond-forming reactions; (d) miscellaneous reactions. © 2013 Bentham Science Publishers.

Loading Changsha University collaborators
Loading Changsha University collaborators