Hunan University of Science and Technology is an institution of higher learning in Xiangtan, Hunan Province of the People's Republic of China. It is under the jointly jurisdiction of central government and provincial government, and is mainly administered by Hunan Province. Hunan University of Science and Technology was formed by the merger of two earlier universities. Wikipedia.
Liu Y.-H.,Hunan University of Science and Technology
IET Control Theory and Applications | Year: 2017
In this study, the authors consider the problem of adaptive tracking control for a class of non-linear uncertain systems in the presence of input saturation. To tackle the effects of the non-smooth saturation non-linearity, a novel approximate saturation model is constructed, which can smoothly approximate the real saturation with arbitrarily prescribed precision. By utilising dynamic surface control approach with the modified linear filters, a robust adaptive control scheme is explicitly designed via the adding an integrator technique. The proposed controller can eliminate not only the 'explosion of complexity' issue inherent in the backstepping design but also the coupling terms with respect to the surface errors and the boundary layer errors. In addition, the stability analysis shows that all the resulting closed-loop signals are semi-global uniformly ultimately bounded. Finally, simulation results are presented to demonstrate the performance of the developed method. © The Institution of Engineering and Technology 2017.
News Article | December 9, 2015
A new report revealed that glaciers on Mount Everest have dropped by 28 percent over the last 40 years. The report was made by researchers from Chinese Academy of Sciences, Mount Qomolangma Snow Leopard Conservation Center and Hunan University of Science and Technology. Researcher Kang Shichang from CAS's State Key Laboratory of Cryospheric Sciences said the report findings involve information collated on longitudinal investigations. The said analyses were performed both via remote sensing and actual on-site evaluation. Aside from the shrinking glaciers, the report also said that Mount Everest or Mount Qomolangma in Tibet has been exuding warmer temperatures in the last 50 years. Then and Now "The glacial shrinkage area is compared to the measurements taken in the 1970s," the press release read. For the rate of glacial shrinkage in the south slope of the mountain, the researchers found a 26 percent decrease. Now, the nature reserve of the mountain has about 1,476 glaciers, which covers 2,030 square kilometers. Kang, who has led multiple glacier investigation groups, said the consequences of shrinking glaciers are the development of wide glacial lakes and higher levels of rivers. As per remote sensing, the size of the glacial lake in the mountain's nature reserve increased from 100 square kilometers in 1990 to 114 square kilometers in 2013. Located between Nepal and China, Mount Everest is the world's largest mountain, standing 8,844 meters high. Large Asian rivers such as those in Ganges and Brahmaputra have the mountain as its source. In May 2015, international experts warned that the 5,500 glaciers in the Hindu Kush- Himalayan (HKH) area may plummet by 70 to 99 percent come the year 2100. HKH is the home of tallest peaks in the world. If the predicted glacial drop persists, farming and hydropower supply may also be affected.
Huang B.,Nanjing Audit University |
Li H.-X.,Nanjing University |
Wei D.-K.,Hunan University of Science and Technology
Knowledge-Based Systems | Year: 2012
Intuitionistic fuzzy information systems are generalized types of conventional fuzzy-valued information systems. By introducing a dominance relation to intuitionistic fuzzy information systems, we propose a notion of dominance intuitionistic fuzzy information systems (DIFIS) and establish a dominance-based rough set model, which is mainly based on the substitution of the indiscernibility relation in classic rough set theory by a dominance relation that is defined on the score and accuracy function of intuitionistic fuzzy value in DIFIS. Furthermore, to simplify the knowledge representation and extract useful and simpler dominance intuitionistic fuzzy rules, we provide two attribute reduction approaches to eliminate the redundant information. Finally, we apply these approaches to computer auditing risk assessment, and by using an application as a case study we acquire some valuable assessment rules. These resulting rules can provide an available method to acquire knowledge from DIFISs. © 2011 Elsevier B.V. All rights reserved.
Liu Q.,Hunan University of Science and Technology
Macromolecular Chemistry and Physics | Year: 2010
Monodisperse hyper-crosslinked polystyrene nanospheres with ultrahigh specific surface area were successfully prepared by emulsifier-free miniemulsion polymerization and post-cross- linking. The specific surface area and the total pore volume of hyper-crosslinked nanospheres were increased with increasing the concentration of vinybenzyl chloride in monomer mixture. The hyper-crosslinked nanospheres exhibited excellent swelling capacity in thermodynami- cally good and poor solvent. Furthermore, the nanospheres with specific surface area of 1223 m2 g-1 adsorbed 2.13wt.-% hydrogen at 163K/1.5MPa. Overall, the present study provided a simple method to prepare mono- disperse microporous hyper-crosslinked polymer nanospheres. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Dai J.,Hunan University of Science and Technology
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2013
Million watt scale directly-driven wind turbines are chosen as the study object and its dynamic characteristics are analyzed at the condition of a blade fracture accident happening. By integrating the wind rotor loads sub-model, electromechanical coupling sub-model and pitch control sub-model, the system models of wind turbines are obtained. In the wind rotor loads sub-model, not only the aerodynamic force but also the inertia force and gravity force are considered; in the pitch actuator sub-model, the dynamic characteristics are considered. According to the established wind turbine models, the corresponding numerical simulation models are constructed in Simulink; the simulation is carried out assuming that wind turbines have yet to be stopped after a few seconds of blade fracture. The research results show that when a blade fracture happening, the wind rotor mechanical rotational torque mutates. Since the generator electromagnetic torque tracks quickly the wind rotor mechanical rotational torque, the wind rotor rotating speed remains near the given value. Furthermore, the energy capture and conversion of wind turbines is out of balance; the DC capacitor voltage, the active power and reactive power injected into the grid have dramatic fluctuations which has impact on the grid. Through the research, the dynamic characteristics of wind turbines are obtained when a blade fracture happening which can provide useful reference for wind turbine structure design, operation control, etc. © 2013 Journal of Mechanical Engineering.
Zong-Chang Y.,Hunan University of Science and Technology
International Journal of Electrical Power and Energy Systems | Year: 2012
Electric load forecast analysis has become increasingly important for the industry. Climate factors are the ones of key factors influencing the load demand. The sun is vital for attributing climate change as the earth is moving (revolution, rotation) in its elliptical orbit around the sun. The paper introduces an elliptic orbit algorithmic model for yearly and daily electric load movement analysis. In the proposed model, electric load movement as a time series is mapped to the polar coordinates to build the algorithmic model that the angular coordinate represents time, and the radial coordinate donates its corresponding electric load. The built model with its elliptical orbit is used for load movement analysis. The proposed approach is applied to yearly load movement evaluation and forecast for State Gird Corporation of China (SG) and its five branches in 2006, and daily load movement evaluation and forecast for one daily load of Shanghai Grid. The experiments yield results agreeing well with their actual loads. The results indicate workability of the proposed. © 2012 Elsevier Ltd. All rights reserved.
Liu W.,Hunan University of Science and Technology
Polymer Engineering and Science | Year: 2010
Aromatic heterocyclic polyimides are used extensively in industries for their excellent mechanical properties, high glass transition temperatures (Tg), and so on. A quantitative structure-property relationship (QSPR) model was developed to predict the Tg values with 54 aromatic heterocyclic polyimides by using an artificial neural network (ANN) back-propagation algorithm. Fifty-four aromatic heterocyclic polyimides were randomly divided into a training set (36) and a test set (18). Three molecular descriptors (the connectivity index X1A, the topological descriptor PW3, and the 3DMoRSE descriptor Mor09e) were selected to produce the mode. Simulated with the final optimum ANN model with 3-3-1 structure, the results show that the predicted Tg values are in good agreement with the experimental ones, with the root mean square errors (RMSEs) of 12.4 K (R = 0.935) and 16.4 K (R = 0.937) for the training set and the test set, respectively. © 2010 Society of Plastics Engineers.
Xin L.,Hunan University of Science and Technology
International Journal of Digital Content Technology and its Applications | Year: 2012
The financial ecology is a new subject in our county which is gaining more and more attention from the experts and scholars. This article Studies the finance ecological environment using the unascertained measure and AHP, and this method not only could evaluate the advantages and disadvantages of the financial environment, but also has an important sense by giving a certain reference to improve financial environment.
Yang Z.-C.,Hunan University of Science and Technology
Environmental Science and Pollution Research | Year: 2014
Nowadays, the issue of air pollution has continuously been a global public health concern. Modeling and forecasting daily movement of ambient air mean PM2.5 concentration is an increasingly important task as it is intimately associated with human health that the air pollution has unignorable negative effects in reducing air quality, damaging environment, even causing serious harm to health. It is demonstrated that daily movement of mean PM2.5 concentration approximately exhibits weekly cyclical variations as daily particle pollution in the air is largely influenced by human daily activities. Then, based on weekly quasi-periodic extension for daily movement of mean PM2.5 concentration, the called elliptic orbit model is proposed to describe its movement. By mapping daily movement of mean PM2.5 concentration as one time series into the polar coordinates, each 7-day movement is depicted as one elliptic orbit. Experimental result and analysis indicate workability and effectiveness of the proposed method. Here we show that with the weekly quasi-periodic extension, daily movements of mean PM2.5 concentration at the given monitoring stations in Xiangtan of China are well described by the elliptic orbit model, which provides a vivid description for modeling and prediction daily movement of mean PM2.5 concentration in a concise and intuitive way. © 2014 Springer-Verlag Berlin Heidelberg.
Liu X.,Hunan University of Science and Technology
Computers and Mathematics with Applications | Year: 2015
To better eliminate the staircase effect and simultaneously preserve edge details, this paper investigates a hybrid regularizers model for image denoising and deblurring. This technique closely incorporates the advantages of the classical total variation (TV) filter and the fourth-order filter. Computationally, we develop an extremely efficient relaxation scheme and alternating minimization algorithm, and give the rigorous convergence analyses there in detail. Provided experimental results distinctly illustrate the high efficiency of the addressed numerical algorithms. Also, in comparison with the recovered results by the state-of-the-art models, simulations manifestly demonstrate the competitive performance of our proposed scheme in reducing the blocky images and sharply maintaining the edge features. © 2015 Elsevier Ltd. All rights reserved.