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Nanjing, China

Hohai University is a research university in Nanjing, China under the direct jurisdiction of the Ministry of Education of China. From 1958 to 2000 it was administered by the Ministry of Water Resources.The university's main focus is the research and study of water resources, and it primarily educates engineering subjects, with coordinated development of engineering, science, economics, management, arts and law. It is part of Project 211 and has set up a graduate school. Wikipedia.

Interval type-2 fuzzy sets (IT2 FS) provide us with additional degrees of freedom to represent the uncertainty and the fuzziness of the real word than traditional type-1 fuzzy sets. In this paper, we investigate the fuzzy multi-attribute group decision making (FMAGDM) problems in which all the information provided by the decision makers (DMs) is expressed as IT2 FS, and the information about attribute weights is completely unknown. We first introduce the concepts of lower and upper possibility mean value of IT2 FS. Based on the crisp standard deviation and mean deviation of IT2 FS, we establish one optimization model to determine the weights of attributes. Furthermore, we utilize the obtained attribute weights and the arithmetic operations to fuse the IT2 fuzzy information in the collective IT2 fuzzy decision matrix to get the overall IT2 fuzzy values of alternatives by which the proposed fuzzy possibility degree of all the given alternatives can be found. Finally, global supplier selection problem is given to illustrate the feasibility and effectiveness of the proposed method. © 2013 TFSA. Source

Ni J.,Hohai University | Yang S.X.,University of Guelph
IEEE Transactions on Neural Networks | Year: 2011

Multiple robot cooperation is a challenging and critical issue in robotics. To conduct the cooperative hunting by multirobots in unknown and dynamic environments, the robots not only need to take into account basic problems (such as searching, path planning, and collision avoidance), but also need to cooperate in order to pursue and catch the evaders efficiently. In this paper, a novel approach based on a bioinspired neural network is proposed for the real-time cooperative hunting by multirobots, where the locations of evaders and the environment are unknown and changing. The bioinspired neural network is used for cooperative pursuing by the multirobot team. Some other algorithms are used to enable the robots to catch the evaders efficiently, such as the dynamic alliance and formation construction algorithm. In the proposed approach, the pursuing alliances can dynamically change and the robot motion can be adjusted in real-time to pursue the evader cooperatively, to guarantee that all the evaders can be caught efficiently. The proposed approach can deal with various situations such as when some robots break down, the environment has different boundary shapes, or the obstacles are linked with different shapes. The simulation results show that the proposed approach is capable of guiding the robots to achieve the hunting of multiple evaders in real-time efficiently. © 2011 IEEE. Source

Chen X.,Hohai University | Wu S.,Hohai University
Construction and Building Materials | Year: 2013

The effect of water-to-cement ratio (w/c) and age on the pore structure of cement mortar was determined through mercury intrusion porosimetry (MIP). The cement mortar specimens were prepared with w/c of 0.4, 0.5 and 0.6, and were tested at different curing ages (14, 28, 180 days). The degree of hydration of the cement in cement mortar was obtained by determining the non-evaporable water content. Test results have shown that, the degree of hydration increased with increasing curing time and water-to-cement ratio of the cement mortar for the ages of cement mortar varying between 14 and 180 days. An increase in the water-to-cement ratio increases the total porosity. In addition, the existing models of pore size distribution of cement-based materials has been reviewed and compared with test results in this investigation. © 2012 Elsevier Ltd. All rights reserved. Source

Jiang Y.,Hohai University | Qiu K.,Hohai University
Materials and Design | Year: 2015

Based on the interaction between the dislocation-sliding and shear-banding, numerical simulations were performed to elucidate the toughening mechanisms of bulk metallic glass (BMG) composites under tension. During the numerical modeling, the free volume theory was applied for the BMG matrix, and free volume density acts as an internal state variable to describe the evolution of shear banding. While the mechanism-based strain gradient plasticity theory was adopted to describe the crystalline second phase, and dislocation density was employed to track the dislocation sliding. With the aid of the user material subroutines (UMAT) in the ABAQUS code, these theories were implemented for predicting the tensile deformation of BMG composites. Numerical results showed that the proposed model could successfully describe the enhanced ductility of BMGs by introducing varied sized of crystalline particles. The predictions were in good agreement with the experimental results. Additionally, the toughing micro-mechanism was clearly clarified from the strong interaction between the dislocation propagation and shear bands. It is further noted that the tensile ductility of a BMG composite is very sensitive to the parameters of the back stress, Taylor factor and particle size. The present results will shed some light on optimizing the microstructures in effectively improving the tensile ductility of BMG composites. © 2014 Elsevier Ltd. Source

Two key issues for landslide forecasting include searching critical slip surfaces and determining their parameters. To solve the former aspect of this problem, a new critical slip surface search method based on an immunised continuous ant colony algorithm is proposed. Artificial immune system and evolutionary algorithms are combined with a continuous ant colony algorithm to form a new bionics algorithm (the immunised continuous ant colony algorithm) for continuous optimisation. The new bionics algorithm was then combined with a limit equilibrium analysis to form a new global optimisation algorithm to search critical slip surfaces. Finally, the proposed method is verified through five typical numerical examples and is compared with a continuous ant colony algorithm and previous studies in the literature. The results indicate that the applicability, validity and effectiveness of the new method are all improved over previous studies and over the continuous ant colony algorithm. © 2014 Elsevier Ltd. Source

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