Table of Content

30 January 2014, Volume 48 Issue 1 Previous Issue    Next Issue

Mechanical instrumentation engineering

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Analysis of Cam Transition Curve Characteristics of  Cam-Rotor Vane Motor XU Chuanhui1,WANG Xuyong1,TAO Jianfeng1,ZHANG Wenjun1,MIAO Zhonghua2 2014, 48 (1):  1-5.  Abstract ( 614 )   Save A novel continuous revolving electro-hydraulic servo cam-rotor vane motor was introduced with its operating principle. The analytic formulae of the motor’s instantaneous torque and speed were derived. The effect of cam-rotor transition curves on improving the motor’s performance and the design criterion were discussed from the aspects of motor’s torque and speed fluctuation, and the dynamic and forcing characteristics of transition curves. The theoretical inference and characteristic analysis of four transition curves were conducted including secondary uniform acceleration-deceleration curve, secondary sine curve, secondary cosine curve and secondary Archimedes curve. Experimental results proved that the secondary cosine curve was suitable for the transition curve of the cam-rotor vane motor, which was used in three-axis motion simulator, and was also in favor of improving the performance of the motor. References | Related Articles | Metrics

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Multi-Physical Field Coupling Analysis of Journal Bearing System under Time-Varying Condition WANG Ning,WEI Zhengying,LIN Qiyin,CHEN Wei 2014, 48 (1):  6-11.  Abstract ( 145 )   Save Aimed at the problem that the non-coupling method cannot analyze the interaction of the bearing bush, lubricating oil and journal, and the problem that the normal FSI method cannot truly reflect the bearing’s working, a novel transient analysis method combined with the computational fluid dynamics (CFD), fluid-structure interaction (FSI), and thermal fluid-structure interaction (TFSI) was proposed. The multi-physical field coupling of the velocity field, pressure field and temperature field based on time-varying condition were studied, taking cavitations into consideration. Eccentricity, temperature rise, as well as the axial trajectory from the startup to the steady state, were accurately calculated under constant load. The effect of cavities, rotational speed, and load on the pressure, eccentricity, temperature rise, and cavitations was considered. The results obtained by the proprosed method agree well with the experimental results. References | Related Articles | Metrics

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Compound Error Compensation Technique for CNC Machine Tools Based on Interpolation Method WANG Wei,YANG Jianguo 2014, 48 (1):  12-21.  Abstract ( 158 )   Save In order to improve the accuracy of computer numerical control(CNC) machine tools, a compound modelling method of geometric and thermal error was presented based on linear interpolation and Newton interpolation. Online realtime error compensation was implemented by applying the CNC external machine zero point shift function and a novel self-developed synthesis error real-time compensation system. The experimental results show that the new model is convenient in calculation and precise in prediction. Therefore it is suitable for the real-time compensation of geometric and thermal error of machine tools in complex industrial applications. References | Related Articles | Metrics

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AVQ Clustering Algorithm and OIF-Elman Neural Network for Machine Tool Thermal Error ZHU Xiaolong,YANG Jianguo,DAI Guisong 2014, 48 (1):  22-26.  Abstract ( 156 )   Save An adaptive vector quantization (AVQ) network clustering algorithm based on feed-forward neural network for the selection of temperature measuring points was proposed in thermal error compensation on machine tools. The method reduces the measuring points from 18 to 3, when adopted on a machining center. Then the relationship between thermal error and key temperature measuring points was established based on the output-input feedback Elman neural network model. The experimental results show that the method proposed can effectively eliminate the coupling among temperature measuring points and improve the accuracy and robustness of the thermal error model. References | Related Articles | Metrics

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Dynamic Modeling of Machine Tool Thermal Error Based on the State-Space Model XIAO Huixiao,YANG Jianguo,ZHANG Yi 2014, 48 (1):  22-26.  Abstract ( 128 )   Save A thermal error modeling method based on the state-space model was proposed,  taking the temperature changes of the key heat sources as the input. Its output—thermal error of the machine tool, was jointly determined by the input, state variables and disturbances. Besides, a subspace identification algorithm was used to obtain the parameters of the model. To investigate its accuracy and robustness, experiments were conducted on a computer numerical control (CNC) machine tool. The result shows that  the statespace model can compensate 70% of the thermal error regardless of the spindle speed conditions, and demonstrates its superiority in robustness in comparison with the modeling results of an auto- regressive model. state-space model; computer numerical control (CNC) machine tool; thermal error; robustness   References | Related Articles | Metrics

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Machine Tool Positioning Error Compensation Based on Adaptive Segmentation and Dynamic Modification   LI Zihan,YANG Jianguo,ZHANG Yi,YAO Xiaodong 2014, 48 (1):  27-32.  Abstract ( 128 )   Save To improve and maintain the machining accuracy of machine tools, this paper proposed a novel compensation method based on adaptive segmentation modeling and dynamic modification. This algorithm can figure out the exact segmentation intervals and the best-fitting polynomial automatically according to the positioning error curve shape and the modeling accuracy requirement. In addition, the compensation model is not a fixed algorithm. It can monitor the real-time temperature field of machine tools, the ambient temperature variation, as well as the working conditions of coolant, and adjust the coefficients for the compensation model. Compensation experiments on the machining center VM850 showed that the compensation method could meet the requirement of realtime error compensation under complex working conditions, with its excellent modeling accuracy and robustness.   References | Related Articles | Metrics

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Analysis of Sealing Performance of Seal Ring End Face with Diamond Pores   CHENG Xiangping,PENG Xudong,MENG Xiangkai 2014, 48 (1):  33-38.  Abstract ( 125 )   Save The finite element method was used to solve the two-dimension Reynolds equation for the isothermal, laminar and incompressible liquid flow between the two faces of a liquid lubricated seal ring, on which one face was etched with diamond macro-pores with constant pore depth. Under different operating conditions, the effects of pore depth, area ratio of pores and periodic on seal performance parameter including the average liquid film thickness, frictional torque, film stiffness and leakage rate, were investigated by solving force equilibrium equation of seal rings. The results show that the seal performance of face seal with diamond macro-pores are better in the scope of the analysis when d1 is 3.5—5 μm,  a is 1.2—1.8 mm, and N is 165—195.   References | Related Articles | Metrics

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Improved Harmonic Wavelet Packet Kurtogram and Its Application TIAN Fuqing1,LUO Rong1,LI Wan2,XIE Yong1 2014, 48 (1):  39-44.  Abstract ( 160 )   Save In order to overcome the defect that the frequency domain was divided by the dyadic mode in the traditional harmonic wavelet packet, an improved harmonic wavelet packet that could divide the frequency domain more finely was proposed. In order to overcome the defect that the parameters of bandpass filter were selected by the experience of the user in the conventional envelope analysis and enhance the performance of kurtogram, by combining the improved harmonic wavelet packet with kurtogram, the improved harmonic wavelet packet kurtogram was given, based on which a method to diagnose the mechanical fault was presented. The simulation and fault signal analysis show the method overcomes the defect in the conventional envelope analysis and enhances the performance of kurtogram.   References | Related Articles | Metrics

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Comparison of Hobbing Interpolation Algorithms of Pascal Curve Gear   WANG Yazhou,HU Chibing,LIU Yongping,WU Zaixin,WANG Bomin 2014, 48 (1):  45-49.  Abstract ( 89 )   Save According to the mathematical model for hobbing Pascal curve gear, interpolation algorithms of hobbing pascal curve gear were obtained. Developing regularity of different interpolation algorithms arc length of segment and machine motion axis were compared, the concept of the arc length of segment uniformity degree was proposed, thereby the uniformity of the arc length of segment could be judged. The experiment shows that the stage equal polar angle interpolation arc length of segment is longest near the minimum curvature radius, the development rate of the stage equal rotational angle interpolation arc length of segment is more stable, and the stage equal arc length interpolation arc length of the segment is equal; The arc length of segment uniformity of the three algorithms were orderly increased, which were the stage equal polar angle interpolation, the stage equal rotational angle interpolation and the stage equal arc length interpolation; The stage equal polar angele interpolation machine motion axis motion was with variable velocity and was difficult to control, the stage equal rotational angle interpolation cutter control was complex, and the stage equal arc length interpolation was practical.   References | Related Articles | Metrics

Astronomy,Geoscience

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Analysis of Synthetic Seismograms at Seafloor Caused by Low Frequency Sound Source LU Zaihua,ZHANG Zhihong,GU Jiannong 2014, 48 (1):  50-55.  Abstract ( 107 )   Save Numerical calculations of range-stacked synthetic seismograms at seafloor caused by low frequency sound source at different shallow sea environments were conducted in this paper with the combination of the FFP model with inverse Fourier transform. According to the calculated results of numerical examples, the time series of seismic wave at seafloor are mostly composed of interface waves and normal mode waves. The time series of seismic wave is dominated by interface wave if the source frequency is less than the minimal cut-off frequency of normal modes. More and more normal modes appear when the source frequency increases and gradually passes their cut-off frequency respectively. The normal modes gradually become the significant carriers of source energy and surface wave weakens accordingly. The more closely the sound source approaches to the seafloor, the more efficiently the seismic wave is excited, and the interface wave prevails in the synthetic seismograms simultaneously. When the source frequency is very low, the seismic wave is more strongly generated in soft seabeds than in hard seabeds, but more weakly when the source frequency is relatively higher. References | Related Articles | Metrics

Communication and Transportation

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Optimal Design of Ring-Stiffened Cylindrical Shell Considering Instability Mode WANG Cunfu,ZHAO Min,GE Tong 2014, 48 (1):  56-63.  Abstract ( 121 )   Save Under the constraint requirements of strength and stability, the ANSYS parametric model and genetic algorithm were utilized to optimize the ring-stiffened cylindrical shell. With the constant length and radius of the shell, the minimum weight was considered as the optimal objective, while the optimal variables are shell thickness, frame dimensions, and frame spacing. During optimization, the difficulty in identifying the stability constraints may lead to the fact that the obtained optimal results may not be the global optimal solution. In order to solve this problem, a method for judging instability mode of ring-stiffened cylindrical shell based on the ANSYS path mapping technology combined with incremental search method was proposed and validated by using the optimal results of ringstiffened cylindrical shell. The results indicate that the proposed method to judge instability mode is effective and the optimization algorithm can converge to the optimal results in a limited time.   References | Related Articles | Metrics

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Light Source Optimization of Surface Defect Detection of Brake Master Cylinder Pistons YANG Ziqi,XU Liming,XIE Bin,LUO Rui,ZHU Zixin 2014, 48 (1):  64-68.  Abstract ( 199 )   Save The characteristics of the defects on the automotive brake master cylinder piston and the difficulties in visual imaging were analyzed. The tridimensional combination system of multiple light sources was designed, which was suitable for the surface defect detection of the piston. Soft light was designed to reduce the noise in the detection image. The mathematical model of light intensity loss in the process of light emissionreflectionimaging was established. The polarization filtering method was proposed and used on the vertical light source and the camera lens. By choosing the polarizing direction of polarizing film, the brightness of the area without defect and the width of the reflective band could be reduced, and the image contrast enhanced. The defects on the piston surface were systematically image captured with the new light source system. The random sampling experiment with 300 sample size shows that the vision inspection after the optimization of light sources has no leak detection. The false positive rate is not more than 2%. The research conclusions can be further applied into other surface defect visual inspection areas.   References | Related Articles | Metrics

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Wear Model and Reliability Prediction of Wear Life for Automotive Fuel Level Sensor LV Zizhou1,LI Shiyang2a,DONG Yu1,MAO Xiangyang1,ZHANG Yansong2b,LI Shulong3 2014, 48 (1):  69-73.  Abstract ( 116 )   Save By analyzing the contact mechanics of the automotive fuel level sensor, a wear model for the fuel level sensor was established using the numerical discretization method. The parameters of this model were obtained by dry wear durability experiment. The reliability life of the rivet and the track was evaluated using Monte Carlo method. The results showed that the proposed numerical model and reliability prediction results of wear life could be applied to the wear simulation of the fuel level sensor.   References | Related Articles | Metrics

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Propeller CFD Uncertainty and  Influence of  Blade Geometry on Its Deformation ZHOU Zhenlong,ZHU Xi,ZHANG Shuai 2014, 48 (1):  74-80.  Abstract ( 211 )   Save In order to study the deformation of propellers under hydrodynamic effect, the 438X (4381, 4382 and 4383) propellers’ open-water performances were calculated based on a RANS equation with shear stress transport (SST) k-ω turbulence model. The uncertainty analysis in computational fluid dynamics (CFD) of 4381 propeller’s openperformance was conducted using three groups of grids. In the coupling progress, the hydrodynamic loads calculated in CFD were transferred to the finite element method (FEM) by the interpolation on the interface between CFD and FEM, and the stress distributions of blades and the deformation of blade tip were obtained. The results show that the blade deformation of composite propeller caused by hydrodynamic loads can be clearly observed. Furthermore, the deformations of skew and rake of different blades tend to be different, which must to be taken into consideration in design of composite propeller and calculation of propeller fluidstructure interaction. Key words： References | Related Articles | Metrics

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Tubular Joint Fatigue Life Reliability Prediction Method Based on Liouville Equation LIU Yong,CHEN Luyun,YI Hong 2014, 48 (1):  81-85.  Abstract ( 142 )   Save The offshore platform tubular joint fatigue life reliability prediction was achieved by employing the  Liouville probability density evolution equation to obtain the fatigue crack probability density function (PDF). In this method the statistical characteristics of alternating stress stochastic process was gained by combining frequency domain and time domain calculation. The expansion method of stochastic processes based on normalized orthogonal bases was employed to expand alternating stress stochastic process as linear combination of time functions and independent random variables. The crack propagation rate equation was converted into the first class of stochastic differential equations in order to set up the Liouville probability density evolution equation, and the numerical analysis method was employed to solve it. The example verified the validity and simplicity of the proposed method.   References | Related Articles | Metrics

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Influence of Bowshape on Hydrodynamic Performance of High Speed Vessels in Head Seas QIAN Peng,YI Hong,LI Yinghui 2014, 48 (1):  86-91.  Abstract ( 154 )   Save Based on the experimental hydrodynamic performance data of NPL 4b, the codes based on the STF (Salvesen Tuck Faltinsen) method and RANS method were developed and validated. Then the ship hulls with different bowshapes were investigated in head seas adopting the STF method and RANS method respectively. The former conditions are Fr=0.8，2≤ωe≤20 and the latter ones are Fr=0.8 and λ=1.5Lpp. The relationships between the wave profile along the hulls and the motions of the ships with the frictional resistance and the residual resistance were discussed respectively. Finally, conclusions on the advantages and disadvantages of the four different hulls were drawn, which showed that the origianl hull  had the lowest frictional resistance, the AXE one had the lowest wavemaking resistance while the wave piecing one performanced best in waves.   References | Related Articles | Metrics

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Group Decision-Making Method for Warship Based on Improved TOPSIS HUANG Sheng1，GUO Haipeng1，HOU Yuanhang2，WANG Chao1 2014, 48 (1):  92-97.  Abstract ( 137 )   Save From the definition of system performance, a simplified evaluation system for warship system performance was constructed. Based on the  fundamental assumption of group evaluation, the group evaluation weighting making method for warship overall scheme forms and the concept of confidence matrix were proposed. By building the group judgement matrix optimization model, particle swarm optimization (PSO) was used to revise judgement matrix, to assure judgement consistency and group consistency of group judgement matrix; the decision-making method based on improved TOPSIS  for evaluation, and the combination of distance and grey correlation degree in the similarity degree formula was introduced to ensure the consistency of location and curve shape of optimal scheme and ideal scheme, and enhance the comprehensiveness of the decision-making rules. The application example  proved that the decisionmaking method was feasible as a new method for ship overall scheme evaluation.   References | Related Articles | Metrics

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Evaluation Method for Kelvin Source Green’s Function YAO Chaobang,DONG Wencai 2014, 48 (1):  98-105.  Abstract ( 148 )   Save The singularities and oscillatory performance of Kelvin source Green’s function which consisted of a local disturbance part and a farfield wavelike part were analyzed and the relative numerical integral methods for the two parts were presented. A well behaved expression of local disturbance part was used to eliminate its singularities, and  an improved method based on trapezoidal integration rule was used to evaluate this part. Meanwhile, variable substitution with auxiliary technique such as local refinement of integral steps in narrow zones near false singularities was applied to calculate the farfield wavelike part function. According to the attenuation performance of the wavelike part, a finite upper limit of this part was employed to improve the efficiency. The numerical test results have proved the efficiency and accuracy of these integral methods. The methods can be applied to calculate wavemaking problem of floating structures in calm water. References | Related Articles | Metrics

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Real-Time Numerical Prediction Method of “Dolphin Motion” HighSpeed Planning Craft LING Hongjie,WANG Zhidong 2014, 48 (1):  106-110.  Abstract ( 199 )   Save Based on the computational fluid dynamics software FLUENT and the longitudinal motion equation of planning craft crafts, a prediction procedure for coupling and solving of planning craft longitudinal motion response was compiled and the numerical simulation of the dolphin motion of three dimension planning craft model in the uniform flow movement was conducted. According to the different speed and different position of the center of gravity,under the condition of the motion characteristics of the heave and pitch of the planning craft, this paper timely numerically forecasts the boat body amplitude of heave and the angle of trim changing characteristic curve of pitch with time. The results show that, when the longitudinal position of the center of gravity lg=0.231L(L is the length of planning craft), and the volume Froude number Fr▽≥2.7, the dolphin motion of the planning craft appears, and with the increase of the speed, the amplitude of the heave ,the angle of trim and the frequency of the response increase; when Fr▽=5.0, lg=0.381L, 0.351L, the dolphin motion of the planning craft appears, and with the retrusive position of the center of gravity, the amplitude of the heave, the angle of pitching and the frequency of the response increase. Key words： References | Related Articles | Metrics

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Active Absorption Wave-Making Using Generalized Predictive Control LI Hongwei,PANG Yongjie,QIN Zaibai,YANG Yi 2014, 48 (1):  111-115.  Abstract ( 171 )   Save An active absorption wave-making model was identified  online with least squares support vector machines (LS-SVM), and a novel method was proposed based on the strategy generalized prediction control  algorithm. A piston-type 2D numerical wave flume was developed with the higherorder boundary element method and mixed Eulerian-Lagrangian free surface condition. Meanwhile, the predictive controller was embedded in it as wavemaking boundary. An absorbing wave-making contrast simulation for irregular wave and a white noise verification test were conducted in numerical wave flume. Using the separating incident and reflected irregular waves method, the test data was also analyzed. Simulation and verification test results verify that the controller has a strong robusticity and quick response ability, and this system has good active absorbing effect for waves commonly used in model tests.   References | Related Articles | Metrics

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Current Effects on Wave Run-Up Characteristics Around Column SHAN Tiebing,YANG Jianmin,LI Xin,XIAO Longfei 2014, 48 (1):  116-124.  Abstract ( 138 )   Save A 3D numerical wave tank suitable for wave-current interactions was created based on Navier-Stokes equations and continuity equations. The wave diffraction and runup effects were simulated in this numerical wave tank. Different wave-current combinations were selected to investigate the current effect on wave disturbance and trajectory of water particles. In order to verify the accuracy of the numerical calculation, a model test on wave run-up in wave alone condition near column wall was conducted. The results show that the values of calculation and model test are in good agreement.   References | Related Articles | Metrics

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Recycling of End-of-Life Vehicle: Regulation, Management and Prospects CHEN Ming，WANG Junjun 2014, 48 (1):  125-131.  Abstract ( 109 )   Save In this paper, the laws, regulations and management systems of end-of-life vehicles (ELVs) in developed countries and China were reviewed. Shanghai ELVs recycling management system was introduced, which provided a roadmap for sustainable development of ELV recycling in China.   References | Related Articles | Metrics

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Scheduling Optimization of Port Tugboat Operation Considering Multi-Anchorage XU Qi,BIAN Zhan,CHEN Yan,JIN Zhihong 2014, 48 (1):  132-139.  Abstract ( 189 )   Save Based on the analysis of the characteristics of the tugboat scheduling problem,  the similarity between the tugboat scheduling problem and the multiprocessor scheduling problem, this paper formulated a 3stage scheduling model considering multianchorage,  aimed at minimizing the total tugboat operation times. A hybrid simulated annealing algorithm was designed to solve the proposed problem. A two-dimensional real integer coding was used to illustrate the solution. The heuristics of the first available tugboat was embedded to generate the initial solution, and the threepoint crossover approach was adopted to generate new solutions. Numerical examples prove that the convergence characteristics of the algorithm are good and the results are better than those obtained from the existing scheduling rules by around 20%. Sensitivity analysis of related parameters reveals that the objective function is most sensitive to the proportion of the shifting-berth operation and ship style, slightly changed by the tugboat deployment scheme, and not sensitive to the handling operation times.   References | Related Articles | Metrics

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Simulation Analysis of Energy Control Strategy for an Extended-Range Electric Vehicle NIU Jigaoa，SI Lulua，ZHOU Sua,b，ZHANG Tonga,b,c 2014, 48 (1):  140-145.  Abstract ( 160 )   Save The basic configuration and operation modes of the series extended-range electric vehicle were analyzed and a novel method for engine choice and fuel economy evaluation was proposed. A co-simulation platform was set up using Cruise and Matlab/Simulink to evaluate the rule-based engine onoff and optimal operation line control strategies. The simulation results with typical driving cycles illustrate that, first, the engine on-off control strategy makes the engine and generator operate at their best efficiency points, and its fuel economy is better than that of the optimal operation line control strategy; secondly, when the optimal operation line control strategy is adopted in the extended-range mode, the engine downsizing will be beneficial and the extendedrange electric vehicle(E-REV) will achieve a better fuel economy and control effect.   References | Related Articles | Metrics

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Optimization of Yard Crane Scheduling with Consideration of Export Container Relocation BIAN Zhan1,XU Qi1,JIN Zhihong1,LI Xiangjun2 2014, 48 (1):  146-153.  Abstract ( 146 )   Save This paper presented a two-phase hybrid dynamic algorithm aiming at obtaining an optimized container retrieving sequence for a crane to retrieve all the containers from a given yard to the ship. The optimization goal was to minimize the number of container relocation operations. The two phases of the proposed dynamic procedure are as follows: in the first phase, a heuristic algorithm was developed to retrieve the containers which needed no relocation directly onto the ship; in the second phase, a dynamic programming within heuristic rules was used to solve the retrieving sequences problem for the rest of the containers. Computational experiments showed that the model and the hybrid dynamic algorithm could solve the retrieving problem of container terminals efficiently. References | Related Articles | Metrics

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Urban Emergency Shelter Locations for Earthquake Disaster Using Time-Satisfaction-Based Maximal Covering Location Model WANG Wei,SU Jingyu,MA Donghui,GUO Xiaodong,WANG Zhitao 2014, 48 (1):  154-158.  Abstract ( 135 )   Save A multi-criteria integrated time-satisfaction-based maximal covering location model of urban emergency shelter locations for earthquake disaster was developed to identify shelter locations and evacuee distributions. First, considering the various conditions of an integrated considering options for urban emergency shelter locations for earthquake disaster, the TOPSIS method was used for the multiple criteria decision-making and comprehensive evaluation of the possible options. Secondly, after investigation on the time-satisfaction function of the supported units, a multi-criteria integrated timesatisfactionbased maximal covering location model based on the maximal covering location model and the partial covering idea was built. The optimal objective of the model was to maximize the satisfaction of both the support department and the supported units. Finally, a hybrid intelligent algorithm based on the genetic algorithm and particle swarm optimization was provided to solve the model. The computational results proved the effectiveness of the algorithm. References | Related Articles | Metrics