Table of Content

30 June 2010, Volume 44 Issue 06 Previous Issue    Next Issue

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Fluid-Structure Coupling Analysis of Dewatering and Excavation in 500 kV Shanghai Expo Underground Substation LIU Jing, CHEN Jin-jian, WANG Jian-hua 2010, 44 (06):  721-725.  doi: 10.16183/j.cnki.jsjtu.2010.06.001 Abstract ( 4049 )   HTML ( 669 )   PDF (1189KB) ( 333 )   Save On the background of 500 kV Shanghai Expo underground substation, a fluid-structure coupling FEM analysis of dewatering and excavation was made based on the Biot's consolidation theory. A pumping test was simulated to determine soil parameters by back-analysis of displacement and pore pressure. A fluid-structure coupling model was built to analyze dewatering and excavation with steady analysis method and birth-death element method respectively. Seepage and stress fields were solved at the same time. With comparison of the calculated and measured values, the fluid-structure coupling method used in the analysis of dewatering and excavation was proved to be correct and feasible. Figures and Tables | References | Related Articles | Metrics

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Bearing Mechanism and Calculation Method of Screw Pile LI Cheng-wei, CHEN Jin-jian, WU Qiong, XIA Xiao-he, WANG Jian-hua 2010, 44 (06):  726-730.  doi: 10.16183/j.cnki.jsjtu.2010.06.002 Abstract ( 4543 )   HTML ( 13 )   PDF (823KB) ( 472 )   Save The vertical bearing mechanism of screw piles was studied by the model test and numerical analysis. The results of the analysis show that the bearing capacity of the screw piles depends on the soil shear strength and a shear zone along the pile will take place in the surrounding soil under ultimate load. Parameter analysis was presented including the pile-soil interface properties, the soil shear strength, and the design parameters of the screw pile. The parameter study indicates that the key factors influence the vertical bearing capacity of screw piles are the soil shear strength, the screw pitch and the width of screw. A calculation method was obtained based on the field test and numerical results. Figures and Tables | References | Related Articles | Metrics

Architechural Science

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The Axial Punching Properties of Postgrouting Concrete Filled Steel Tube WANG Meihua 2010, 44 (06):  731-0734.  Abstract ( 3954 )   Save Postgrouting concrete filled steel tube is ordinary technology in vertical bearing structures. Based on the experiment, this paper evaluated the mechanics performance of axial punching of postgrouting concrete filled steel tube and summarized the various methods’ influences on the axial punching. By using experimental data and inverse analysis method, the related parameters for interface properties were obtained. This paper summed up the deformation characteristics of the postgrouting connection between the original concrete columns and steel tube connection under the action of axial punching. Based on the experiment and numerical method, the postgrouting connection method of interface was proposed, which provides a reference for future related projects. Related Articles | Metrics

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Damage Detection for the Cantilever Beam with Transverse Crack LI Xiaofeia，YU Yinb 2010, 44 (06):  735-0738.  Abstract ( 3809 )   Save A damage detection method for the cantilever beam with transverse crack was proposed. According to the theoretical analysis, damage of the beam is modeled as an additional flexibility. The relationship between the transverse displacement and the location of the damage and the additional flexibility was constructed. The ratio of the moment of inertia of the cracked section to the moment of inertia of the intact section is defined as the coefficient of the moment of inertia. A formulation for calculating the coefficient of the moment inertia from the additional flexibility was constructed using the FEM simulation. The status of damage is estimated according to the coefficient of the moment of inertia. An example about a trapezium crosssection cantilever beam was given to validate the correction of the formulation and the method. Related Articles | Metrics

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Analysis on Calculation Model for Seismic Damage Index of the Superimposed Slab Shear Walls LIAN Xing1，2,YE Xianguo1，CHANG Lei1,JIANG Qing1，WANG Decai1 2010, 44 (06):  739-0744.  Abstract ( 3582 )   Save To conduct systematically analytical study to this shear walls and to provide reliable scientific basis for the local standards, comparative experimental studies on superimposed slab shear walls and general shear walls under low cyclic loading were conducted. The structural failure feature, ductility, stiffness, energy dissipation were analyzed systematically. The seismic damage model based on stiffness and the seismic damage model based on displacement and energy were analyzed. The calculating results are in good agreement with the experimental phenomenon. The seismic damage model based on stiffness computed is more easy and could be used first. Related Articles | Metrics

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Modeling and Simulation of the Airport Terminal Air Conditioning System Based on Energyplus YANG Chen，JIN Xinqiao，DU Zhimin，FAN Bo，YANG Xuebin 2010, 44 (06):  745-0748.  Abstract ( 4372 )   Save The building energy simulation software, Energyplus and Designbuilder, were employed to set up a simulation model for an airport building and the corresponding HVAC system. Based on annual onsited measured energy consumption data and FEMP (federal energy management program) standard method, an improved FEMP standard method and paired samples ttest method were introduced to verify the simulation model, the results indicate that the simulation model shows a reasonable agreement with the real system. On the basis of the verified model, the effect of supply air temperature optimal setting was simulated and analyzed to assess energy consumption for the system. It was found that decreasing the supply air temperature exhibits a favorable impact on energy saving. Related Articles | Metrics

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Ultimate Bearing Capacity of ConcreteFilled Circular Steel Tubular Short Columns under Axial Compression LIANG Benliang，LIU Jianxin 2010, 44 (06):  749-0754.  Abstract ( 4029 )   Save Under the state of axial compression for short columns with concretefilled steel tube, considering the contribution of axial stress of steel tube when yielded, the thickwalled tube theory and twin shear unified strength theory were introduced to analyze the steel tube. DruckerPrager strength criterion was used to analyze the core concrete bearing capacity. Through these methods, the formula for calculating ultimate bearing capacity of concretefilled steel tube was deduced. Compared with the existing experimental data and other equations, the computed results are in good agreement with them and it can provide a new approach to calculate the ultimate bearing capacity of core short columns with concrete filled steel tube under axial compression. Related Articles | Metrics

Communication and Transportation

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The Advanced Grade Evaluation of Selfelevating Drilling Unit WANG Yunlong，JI Zhuoshang，LIN Yan 2010, 44 (06):  755-0757.  Abstract ( 3500 )   Save The advanced grade evaluation method for a selfelevating drilling unit was proposed. The corresponding evaluation criteria system and calculation method were used to assess the capability of selfelevating drilling unit. The availability of evaluation criteria system and calculation method for selfelevating drilling unit was proved. The evaluation result may be used to carry out the position in advanced level in the same type platform, appraising if the selfelevating drilling unit achieves the desired results and finding the exist problems to guide the work in the future. At the same time, this evaluation criteria system and calculation method will be beneficial to the national standard of the function level grade valuation system of ships and ocean structures. Related Articles | Metrics

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Strength Test of the Integrated Mast under Ship Sway YAO Xiongliang,YANG Wenshan,ZENG Lingyu,ZHANG Lingjiang,ZHANG Aman 2010, 44 (06):  758-0762.  Abstract ( 3975 )   Save According to mechanical principle, experiments were conducted on the integrated mast, which is enclosed, to research on its stress under ship sway by using an inverted model method. The experimental results correspond with the numerical calculation results well. This paper summarized the variation of the stress response of mast’s structure with the period and amplitude of the ship sway by analyzing the measurement results in a large number of working conditions. The research aims to provide reliable reference data for the structure design of newstyle mast, and to provide a new idea for the structure experiment of the ship mast. Related Articles | Metrics

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Numerical Study of Green Water on a Freely Moving Ship in Head Wave LIANG Xiufeng,YANG Jianmin,LI Jun，LI Xin 2010, 44 (06):  763-0768.  Abstract ( 3885 )   Save Based on CFD software FLUENT, the secondary development was conducted targeting at a full solution for numerical simulation of green water problem. This solution consists of dynamic mesh, numerical wave tank integrated with piston type wavemaker and a dissipation zone, an automatic strategy for calculating ship motion, water surface capturing scheme——VOF method, high efficiency mesh plan and an accurate timestep. The solution was put into use on a freely moving ship in head wave. During the simulation, motion of the ship was calculated; and both the evolution process of green water and the impact load of green water were recorded. Related Articles | Metrics

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Several Critical Technologies of the WholeShip Structural Analysis through FEM WANG Congjing,XIA Lijuan 2010, 44 (06):  768-0773.  Abstract ( 4179 )   Save A 6 000 t deck barge was taken as an example to expound the process of direct calculation method of the wholeship FEA. Efforts were being made especially on several key technologies such as the different simulation methods of cargoes loaded on the deck (virtual beam method, multipoint constraints method and mass point method), the selection of bending moment and torque reference point on the section, etc. Furthermore, some recommendations were put forward, based on which the global structural strength evaluation was achieved. This research will provide certain reference for the application of relevant critical technologies in the wholeship structural analysis through FEM. Related Articles | Metrics

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Antigrounding Ship Route Planning Based on Genetic Algorithm YANG Xin，LIU Xiaoming，XU Tingting 2010, 44 (06):  774-0777.  Abstract ( 4137 )   Save VTS(Vessel traffic services) operators in practical work usually assist ships to avoid grounding by virtue of subjective feeling and experience and the worldwide research on it mainly focuses on the grounding probability. This paper proposed a novel method of using genetic algorithm to search a new route and discussed its feasibility and validity. The fitness function conforms to the following requirements: short route length, less summed turning course, no grounding danger and being in the navigation channel. The results show that it costs less and it can accelerate the convergence of the population significantly to one solution. Only changing turning points number, the solutions are very approximate and meet the requirement of this design. The approach is effective and feasible. Related Articles | Metrics

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Study on the Dynamic Load of Rope and Its Effect on Floating and Stability of Revolving Crane Vessel CHEN Xinquan,HE Yanping,LI Hongliang,TAN Jiahua 2010, 44 (06):  778-0781.  Abstract ( 4015 )   Save Additional dynamic loading generated by wire rope swinging due to waveinduced motion of the crane vessel adversely affects its buoyancy and stability. A hydrodynamic model of revolving crane vessel “LANJING” was built to calculate the motion response in irregular waves. Spectral analysis was employed to calculate the motion transfer functions from fulcrum of suspension to lifted object and the statistic characteristic value for lifted object motion. Characteristic value for additional dynamic loading, whose influence on buoyancy and stability of the crane vessel was also analyzed in this study, was obtained according to different waves, rotation angle and rope length. Related Articles | Metrics

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Analysis of the Similar Model for Ultimate Strength Subjected to Combined Action of Bending and Torsion of a Container Ship SHI Guijie,WANG Deyu 2010, 44 (06):  782-0786.  Abstract ( 3641 )   Save The design conditions about a ship similar model under the action of bending and torsion were derived based on the thinwalled beam theory, and then one method about independently dealing with stiffeners and plates was presented. One container ship was studied as an example, a mathematic model optimizing the similar model was set up, and then based on multiisland genetic algorithm the unfeasible design was improved into the feasible region. Using the nonlinear FEM method validates the consistency of the real ship’s and similar model’s ultimate strength under the action of bending and torsion, so the similar model can be used to test the real ship’s ultimate strength. Related Articles | Metrics

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Platoon Stability Based Safe Headway and Its Determination WANG Fenghuia，YANG Mingb，YANG Ruqinga，WANG Chunxianga 2010, 44 (06):  787-0791.  Abstract ( 3685 )   Save To determine the safe headway of adaptive cruise control vehicles, the platoon stability based headway was proposed by using the interconnected systems stability theory. Based on the following control model of vehicles, the local stability of platoon was analyzed, relationships between the safe headway and the global stability of platoon were studied, and the determination method of this headway was given. The test results show that the safe headway determined by the proposed method can ensure the securities of all vehicles in the platoon in different situations. Related Articles | Metrics

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Research on the Interdependencies between Trip Chaining Behavior and Travel Mode XIANYU Jianchuan,JUAN Zhicai 2010, 44 (06):  792-0796.  Abstract ( 4222 )   Save Based on the analysis of travel survey data, this paper developed and appliesd the recursive simultaneous bivariate probit modeling method to model the relationship between trip chaining and travel mode behavior of home based commuting trip chain. The analysis is carried out from two directions, namely trip chaining to travel mode, and travel mode to trip chaining. The developed model takes into consideration the effects of interdependencies between trip chaining and travel mode choice on each choosing behavior, which emphasizes the guidance of decision mechanism on travel behavior forecasting. The results show the pattern that trip chaining drives mode choice is the dominating trend. This means travelers first decide how to organize different activities and travel into trip chains based on individual and family needs and then make travel mode choice condition under the limit of trip chaining. These findings have important implications for travel demand forecasting and for the design and carrying out of demand management measures. Related Articles | Metrics

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Transfer Income Distribution between Rail Transit and Bus Transit Based on Extenics CHEN Peng1,2，YAN Xinping1,2，LI Xuhong3，WU Chaozhong1,2 2010, 44 (06):  797-0802.  Abstract ( 3631 )   Save To address transfer income distribution conflict between rail transit and bus transit and maintain the stability of enterprise operation coordination, extenics was applied to provide income distribution scheme for enterprises. Influence factors of income distribution conflict were analyzed from two aspects which are contribution and risk, and then the proportion formula of transfer income distribution was proposed. And the formal matterelement model and extension model of the issue were established to measure the degree of income distribution conflict. On the basis of constructing the simple cost implication system for public transport enterprise, the method of condition transforming bridge was introduced to generate the possible options of income distribution coordination. And the extension priority degree evaluation method was introduced to filter possible options. The analysis results of the example show that the extension method can better solve the problem of transfer income distribution. Related Articles | Metrics

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Shake Table Test Study of a Bridge Column Based on Statistical Wavelet Packet Energy Method GE Jiping1,WANG Zhiqiang2,LI Husheng1 2010, 44 (06):  803-0806.  Abstract ( 3760 )   Save Considering that the acceleration time history response contains the structure characteristic information, and the wavelet packet energy distribution varies in different condition of the same structure, the characteristic information of the structure was excavated in the eyes of wavelet packet energy. Taking the serial acceleration time history response from shake table tests of a reinforced concrete bridge column as the object of study, the wavelet packet method was used to carry on the statistical analysis of the wavelet packet energy character of the different condition, including the mean, the variance, the standard deviation, the relative average deviation, and the relative standard deviation of wavelet packet energy. The results of different index indicate that the mean of wavelet packet energy can represent the rule that the structure response increases gradually with the increase of acceleration; the values of different index under the same conditions vary with the dynamic performance and stiffness distribution of structure. Related Articles | Metrics

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The Effect of Bohai SeaCrossing Passage on the Traffic Accessibility of Eastern Coastal Area in China WANG Zhenbo1,XU Jiangang1,SUN Dongqi2 2010, 44 (06):  807-0811.  Abstract ( 4040 )   Save Based on the matrix raster data of whole China, using costweighted distance algorithm with ArcGIS 9.3 platform, this paper quantitatively analyzed the positive role of the improvement of traffic accessibility in China due to the construction of Bohai Sea Straits Passage(BSSP). The study shows that the costweighted distance algorithm is scientifically and accurately suitable for the traffic accessibility comparison of preand post great infrastructures. The “China effect boundary” of BSSP is the southern area of the “Xuanhui River estuary of Hebei provinceGaolan county of Ningxia Hui autonomous regionShache county of Xinjiang uighur autonomous region” line and the northern area of the “Suizhong county of Liaoning provinceDongwuzhumuqin banner of inner mongolia autonomous region” line. After the construction of BSSP, the time cost between the two sides of BSSP decreases much and the accessibility area of the node cities increases significantly, which follows the spatial decline law. The accessibility impact on coastal cities of BSSP is more than that on inland cities, and that on the southern area of Yangtze river is more than that on the Northeast. Related Articles | Metrics

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The Effect of Longitudinal Layout of Floating Slabs onthe Overhead Railway YANG Guangjun1，HUANG Xingchun2，LI Guanghui1，GUO Hao2 2010, 44 (06):  812-0815.  Abstract ( 3408 )   Save A dynamic model for the prefabricated floating slabs was presented on the basis of analysis of a floating slab track system. In the model, the floating slabs are regarded as rigid bodys supported by elastomer bearings. By exploring the effect of the layout of floating slabs on the trainbridge coupled vibration characteristics, a reasonable layout configuration of floating slabs on the floating slab track system was obtained. Related Articles | Metrics

Astronomy,Geoscience

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Analysis and Suppression on the Dynamic Amplification Factor of Selfelevating Offshore Platform HUANG Zhaoyu1,2,TANG Wenyong1,WANG Yi2,WANG Wentao2 2010, 44 (06):  816-0819.  Abstract ( 4147 )   Save Based on the selfelevating platform structure and the Stokes 5th wave theory, the dynamic and static shear forces of the foundation were computed and analyzed. Then the detailed calculation method was compared with the singlefreedomdegree method, which is much more conservative. Finally, the mechanism of the suppression on the dynamic amplification factor(DAF) was analyzed and the real DAF value was reduced through the increase of the platform stiffness. Related Articles | Metrics

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Mooring Performance of Nonlinear Elastic Mooring Lines YUAN Meng,FAN Ju,MIAO Guoping,ZHU Renchuan 2010, 44 (06):  820-0827.  Abstract ( 4101 )   Save A numerical model was established using finite element method in time domain for fiber mooring lines. For different water depths, the displacementlateral force relations were compared for three types of mooring system and the corresponding effective utilization rates were calculated. This shows that it is more competitive for the taut mooring system using lightweight fiber lines than the other ones in deep water. The dynamic analysis of the polyester mooring line was conducted, where a linear material property was proposed to fit the nonlinear stressstrain relations, the result was compared with the nonlinear elastic model. It was found that the simulation by linear fitting to the material properties in the numerical model can not obtain a reasonable result and it is necessary to use nonlinear elastic model for fiber lines. For the mooring system of a Spar, three types of fiber lines were used respectively. Dynamic analysis was performed and all tensions of the threetype lines were compared. The results show that polyester mooring lines present the best performance. Related Articles | Metrics

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Numerical Simulation of Towed LowTension Cable WANG Fei,CHEN Jingbiao,TU Xinghua 2010, 44 (06):  828-0832.  Abstract ( 3787 )   Save This paper developed a mathematical model to investigate the dynamics of low(negative)tension cable, in which bending moment plays an important role in cable dynamics. Lumped mass method(LMM) was employed to describe the cable dynamics, a new three dimensional scheme was proposed to compute the bending momentinduced load from the relationship between moment and distributed load, which was then incorporated into the governing equation of LMM, the equation was solved by the 4th order RungeKutta integrating procedure. Numerical cases were presented for lowspeed towing, which illustrate that the effect of bending moment can not be neglected in order to get reasonable result, and also validate the proposed scheme. Related Articles | Metrics

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Numerical Analysis on the Flying of Yigong HighSpeed and Long Runout Landslide at the ShortRange Stage ZHOU Xin，XING Aiguo，CHEN Lujun 2010, 44 (06):  833-0838.  Abstract ( 4100 )   Save Many large highspeed and long runout landslides could fly in the air at the shortrange stage. The aerodynamic effect was studied for the case of highspeed sliding mass flying at the shortrange stage. The motion differential equations were educed in consideration of the ground effect. Taking the Yigong landslide in China as an example, this paper applied the numerical analysis method to study the flying law of highspeed sliding mass. The calculated results illustrate that, because of the aerodynamic effect to the sliding mass, the horizontal thrust force and vertical lift force both increase. The horizontal speed increases, but its amplitude is little. At the same time, the vertical speed tends to increase more slowly. Therefore, the flying time is longer and the distance is farther than those without consideration of the aerodynamic effect. The results are more reasonable by comparison with the field observation. Related Articles | Metrics

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Application of Maximum Entropy Distribution in Longterm Wave Height Statistics CHENG Jingjiao,ZHU Zhixia 2010, 44 (06):  839-0843.  Abstract ( 3523 )   Save The maximum entropy probability density function (PDF) was derived based on the maximum entropy principle. In addition, the widely used parameterized model in longterm significant wave height distribution was introduced. The two methods were applied to describe the longterm significant wave height distribution. In order to test the accuracy of these two methods, the longterm winds and waves data measured by buoys in the East China Sea were selected to fit the significant wave height distribution. Moreover, PDFs of the abovementioned two methods were compared with the observed data. The result shows that the value of parameter γ in PDF of the maximum entropy distribution can demonstrate the complexity of the sea states, besides, PDF of the maximum entropy distribution fits well at different wind speed. Whereas the PDF derived from the parameterized model fits better with the observed data at lower wind speed than at higher wind speed; the derivation occurs in the latter case. Related Articles | Metrics

Mathematics

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The Wiener Index of Unicyclic Graphs with Perfect Matching CHEN Yahong 2010, 44 (06):  844-0848.  Abstract ( 4052 )   Save This paper investigated the properties of the Wiener index of unicyclic graphs, which are used to give a lower bound for the Wiener index of unicylic graphs of order 2β having perfect matching.Moreover,all extremal unicyclic graphs which attain the lower bound were characterized. Related Articles | Metrics

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Asymptotic Behavior of Discontinuities in Thermoelasticity with Second Sound and Variable Coeffcients LI Zheng,WANG Yaguang 2010, 44 (06):  849-0854.  Abstract ( 3621 )   Save This paper mainly studyied the asymptotic behavior of discontinuous solutions to the Cauchy problems for linear and semilinear thermoelastic equations with second sound and variable coefficients in one space variable. When the relaxation parameter goes to zero, the discontinuity of temperature vanishes, and discontinuities of elastic waves and heat flux are propagated with the elastic speeds. Moreover, these discontinuities decay exponentially when the time goes to infinity, and the decay rates not only depend on the growth rate of the nonlinear source terms and the heat conduction coefficient, but also depend on the change rates of the elastic speeds. Related Articles | Metrics

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An HIV-1 Infection Model with Time Delays YANG Yu 2010, 44 (06):  855-0858.  Abstract ( 3858 )   Save A delayed HIV-1 with Holling II type infection model was investigated. Using the uniform persistence theory and successive iteration method, the conditions on the permanency of the model and the global asymptotic stability of the endemic equilibrium were obtained, which improve the results in the relevant literatures. Related Articles | Metrics

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Bifurcations in Threedimensional Competitive LotkaVolterra System Living in Two Patchy Environment WANG Ruiping 2010, 44 (06):  859-0862.  Abstract ( 3129 )   Save This paper, studied bifurcations in threedimensional competitive LotkaVolterra system living in two patchy environments. It is studied about asymptotical stability of equilibrium with threespecies alive when there is no crossdiffusion within the two patchy. And, there are some different critical values of the bifurcation parameter at which the system undergoes Hopf bifurcation, static bifurcation respectively under the effect of crossdiffusion. Some examples were also given. This illustrates the crossmigration response is very important factor that should not be ignored. Related Articles | Metrics

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A New Kind of Domination in Regular Graphs PENG Mao 2010, 44 (06):  863-0867.  Abstract ( 3697 )   Save An ［r,R］dominating set is a distance rdominating set which can be connected by adding paths with length within R. In this paper, it was restricted in random regular graphs and several algorithms were designed to approximate the minimum ［r,R］dominating set. After analyzing its average performance by using differential equations, an upper bound was achieved as well. Related Articles | Metrics

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An Improved Multivariate EWMA Control Chart TANG Linghan1,MIAO Rui1,YANG Dong2,ZHAO Yanzheng1,JIANG Zhibin1 2010, 44 (06):  868-0872.  Abstract ( 3855 )   Save This paper researched on the optimization of multivarate exponentially weighted moving average(MEWMA) control chart. In the retrospective phase, a new covariance matrix S2 based on successive differences is recommended for estimating the common covariance matrix Σ. An improved MEWMA chart based on estimator S2 was established. When step shifts or ramp shifts in mean value occur, the signal probabilities and ARLs(average run length) of two MEWMA charts are compared. According to the simulation results, the new control chart presents a remarkable optimization with large smoothing factor r and noncentrality parameter λ. Related Articles | Metrics