交通运输工程学报

Classification of expressway landscape sensitive zone based on dynamic visual characteristics

XU Jin-liang, WANG Rong-hua, FENG Zhi-hui, WANG Zi-geng

Abstract: The dynamic visual characteristics of drivers were analyzed, the change laws of driver' s horizontal visual degree, foreground vision, fixation point and the deepest vision with the change of speed were studied, the model of expressway landscape sensitive zone was proposed based on drivers' dynamic visual characteristics, and the functions of landscape sensitive zones were derived.The landscape sensitive zone scopes of bidirectional four-lane expressways at different speed limit levels were calculated by using landscape sensitive zone model, and the classification result was gotten by using landscape sensitive functions.The attributes of different landscape sensitive zones and the design key points of landscape elements were described.The relationship between slope width and the first class landscape sensitive zone scope was studied through contrast tests.Analysis result indicates that the landscape sensitive zone scope of bidirectional four-lane expressway is 545 m, the scopes of the first, second and third classes are 55, 260, 230 m, respectively, and the first class zone is the most sensitive one.The gradient can be revised to change the proportion of side slope width in expressway landscape sensitive zone whendesigning the side slope landscape, and the smaller the gradient is, the higher the landscape sensitivity is.More>

2015, 15(2): 1-9. doi: 10.19818/j.cnki.1671-1637.2015.02.001

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Evaluation index system of green ecotype city road

LI Man-liang, ZHENG Chen, WANG Chao-hui, CENG Wei, DI Sheng-guan

Abstract: In order to evaluate green ecotype city road scientifically and rationally, the concept of green ecotype city road was proposed, and the evaluation index system was set up from 5aspects, namely, rationality of design, effect of road function, energy-conservation and emission-reduction effect, greening effect and environmental protection effect.5first grade indexes, 14 second grade indexes and 31 third grade indexes were elaborated, and their evaluation standards were determined.The evaluation method of green ecotype city road was established on the basis of Spearman rank correlation coefficient combination determining method and interval approximation method.The green ecotype road of China-Singapore Tianjin Ecotype City was evaluated by using the method and the index system.Evaluation result shows that for the road, 21 third grade indexes are excellent and 10 third grade indexes are good.12 second grade indexes are excellent and 2second grade indexes are good.2first grade indexes, namely, rationality of design and environmental protection effect are good and the rest are excellent.The distance between the excellent evaluation grade and the evaluation index set of green ecotype city road is 3.82, and is smallest in the distances between the evaluation index set and the evaluation grades, which shows the greenecotype city road is excellent and the evaluation result is consistent with the reality.Therefore, the evaluation index system and the evaluation method are reasonable and reliable.More>

2015, 15(2): 10-21. doi: 10.19818/j.cnki.1671-1637.2015.02.002

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Calculation method of ultimate bearing capacity for plain concrete column

LIN Shang-shun, CHEN Bao-chun

Abstract: The tests of ultimate bearing capacity for 19 plain concrete columns were carried out.The reasonable scopes of slenderness and eccentricity of plain concrete columns were proposed.The bearing capacities of test columns were calculated by nonlinear finite element method.A calculation method of ultimate bearing capacity for plain concrete column was presented by theoretical analysis and regression of test data.Calculation result shows that when the slendernesses of test columns are higher than 15 and the eccentricities are 0.3, their failure modes are section tensile failure, which can not play full material performance of compression.When the slendernesses are not higher than 15 and the eccentricities are not higher than 0.3, their failure modes are section compression failure.The mean ratio of calculated values by the finite element method to test values is 0.995, the variance is 0.001 8, so the calculated value fits well with test value, and the finite element method can be used for the parameter analysis of plain concrete column.Based on considering the coupling influence of slenderness and eccentricity on bearing capacity, in the proposed calculation method of ultimate bearing capacity, the mean ratio of calculated values by the proposed method and the finite element method is 0.976, the variance is0.003, which indicates that the proposed method has high precision and high safety.More>

2015, 15(2): 22-31. doi: 10.19818/j.cnki.1671-1637.2015.02.003

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Flexural properties and influence factors of continuous RC beam strengthened with near-surface mounted mixing FRP tendons

WANG Xing-guo, ZHU Kun-jia, ZHENG Yu-zhou, ZHENG Dan-dan, XIAO Shi-ya-ren

Abstract: The flexural properties of four continuous reinforced concrete(RC)beams strengthened with near-surface mounted(NSM)mixing fiber reinforced polymer(FRP)tendons were studied by static test.The influence factors of bearing capacities of test beams were analyzed by finite element analysis(FEA)software, such as strength of concrete, initial load, elastic modulus and content of FRP tendons.Analysis result indicates that the reinforcement effect without debond between FRP tendons and concrete is significant.Compared with unstrengthened RC beam, the yield load and ultimate load of strengthened RC beam can increase by 31%and 56%respectively.When concrete strength, elastic modulus and content of FRP tendons increase, the yield load and ultimate load can increase by 38% and 17% respectively.When initial load increases, the yield load and ultimate load can decrease by 6% and 24% respectively.For test RC beams, the mean ratio of simulation and test values for the yield load is 0.969, 0.962 for the ultimate load, 1.104 for the midspan yield deflection, 1.024 for the midspan destructive deflection, and the trends ofsimulation load-deflection curves are basically consistent with test curves, so FEA result is in good agreement with test result, and FEA can accurately simulate the mechanical properties of test beam.More>

2015, 15(2): 32-41. doi: 10.19818/j.cnki.1671-1637.2015.02.004

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Three-dimensional hydraulic design of axial waterjet pump

CAO Yu-liang, WANG Yong-sheng, JIN Shuan-bao

Abstract: By using three-dimensional design method based on circulation and computational fluid dynamics, the effects of blade number, blade circulation center position and blade trailing edge circulation on rotor performances were studied, the influences of leading edge circulation and trailing edge circulation of stator on axial waterjet pump performances were analyzed, and an axial waterjet pump with high efficiency and good cavitation capacity was designed by controlling the factors properly.When the flow is 56.2m3·s^-1, the head, power and efficiency of the pump are 35.9m, 21 465 kW and 92.3%, respectively, so the properties and efficiency of the pump are high.Analysis result shows that increasing blade number is effective to decrease single blade torque, when blade number increases from 5to 7, single blade torque decreases by 21%.Circulation center moving closer to trailing edge is beneficial to better cavitation performance of rotor, when circulation center moves from 3/10 to 7/10 of blade string length, cavitation area on rotor suction side decreases by 80%.The slope of rotor trailing edge circulation affects rotor efficiency, when the slope changes from 0.8to 1.2, rotor efficiency increases gradually.Rotorhead and rotor power almost increase linearly when trailing edge circulation ranges from 0.4to0.5, rotor head increases by 19.9%, and rotor power increases by 19.5%.Pump efficiency firstly increases and then decreases with the ratio increase of stator leading edge circulation to rotor trailing edge circulation, and the efficiency is highest when the ratio is 0.93.Stator trailing edge circulation has effects on pump efficiency, outlet non-uniformity and outlet circumfluent energy, when stator trailing edge circulation is-0.05, pump efficiency is highest, and outlet non-uniformity and outlet circumfluent energy are least.More>

2015, 15(2): 42-49. doi: 10.19818/j.cnki.1671-1637.2015.02.005

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Uprighting process analysis of big-angle tilted aground ship

PAN De-wei, LIN Cheng-xin, SUN De-ping, LIU Zhi-jie, ZHOU Chao-yu

Abstract: In order to study the uprighting process of big-angle tilted aground ship, the uprighting force, heel angle and draft of the ship were computed.The mechanical model of aground ship was established based on its mechanical characteristics, and the influences of heel angle, draft, driving depth and natural properties of seabed soil on hull were analyzed.Taking a big-angle tilted aground LNG tanker as an example, the uprighting force, total aground force, shear, moment and torque of the tanker in the uprighting process were solved by the simulation of GHS software.Different uprighting schemes were compared, and the influences of uprighting modes, aground positions, superstructures and liquid gas storage tanks on uprighting process were analyzed.Analysis result shows that the changing trends of mechanical parameters of three schemes are similar.The larger differences are 9.1%-20.0% among the maximum uprighting forces of three schemes.The aground force, shear force and moment reach the maximums when the heel angle ranges from-55°to-50°.The stage need not exert larger uprighting forces, butthe force situation of hull should be noticed.The torque changes enormously when the heel angle ranges from-120°to-100°.The opposite changing phenomenon of moment and torque directly threatens the safety of hull structure, so it should be handled with more care during uprighting process.The appropriate uprighting scheme is selected by considering the positions of points of uprighting forces and the reliability for the safety of hull and environment during uprighting process.More>

2015, 15(2): 50-58. doi: 10.19818/j.cnki.1671-1637.2015.02.006

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Field-zone coupling model of fire smoke propagation in ship cabin

WANG Jin-hui, JIAO Yu, XU Tao, CHEN Wei-jiong

Abstract: Aiming at the fire smoke propagation in large ship cabin, the limitations of field model FDS and zone model CFAST were analyzed.Based on the principles of energy transmission, component transformation and pressure balance, the field-zone coupling model of smoke propagation in ship cabin was developed, and the small scale experiment platform with4 temperature measuring points of ship cabin fire was set up to verify the effectiveness of the established coupling model.The simulations of fire smoke propagation in ship cabin were carried out by field model, zone model and field-zone coupling model respectively, and the simulation results of temperature and smoke layer height were compared.Analysis result shows the temperatures of 4measuring points increase with the increase of time, the measuring point near fire has higher temperature at the same time.With the increase of distance from fire, the temperature of measuring point falls, and the slight fluctuations of the temperatures at4 measuring points appear due to smoke turbulent flow.When fire burning reaches steady state, the change regular of smoke layer height can be simulated by using the models, and the simulation result by using field-zone coupling model is better than the simulation results by usingfield model and zone model.The calculation time for field-zone coupling model is about 54%less than the calculation time for field model.The simulation result by using field-zone coupling model is consist with the test result, so the field-zone coupling model has better engineering value.More>

2015, 15(2): 59-69. doi: 10.19818/j.cnki.1671-1637.2015.02.007

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Dynamic multi-objective optimization model of arrival and departure flights on multiple runways based on RHC-GA

ZHANG Qi-qian, HU Ming-hua, ZHANG Hong-hai

Abstract: The minimum control workload and flight delay were taken as objective functions, wake turbulence separation, runway restriction and the maximum position limit were taken as constraint conditions, and the dynamic multi-objective optimization model of arrival and departure flights on multiple runways based on RHC-GA was set up by considering the latest operation standards of Civil Aviation Administration of China.For the large solution scale of the proposed model, genetic algorithm was designed to solve the proposed model with the dynamic characteristics of receding horizon control strategy, and the 48 flights data in the peak period of a large Chinese busy airport were selected to verify the model.Simulation result shows that when the unit flight costs of heavy, medium and light aircrafts are 25, 16, 10yuan·s^-1 respectively, the total delay cost is36 098 yuan and the control workload is 32 sorties by using the first come first served(FCFS)strategy.The total delay cost is 28 900 yuan and the control workload is 31 sorties by using the receding horizon control strategy with 5receding horizons, the total delay cost is 27 375 yuan andthe control workload is 32 sorties by using the receding horizon control strategy with 4receding horizons, and the total delay cost is 27 194 yuan and the control workload is 33 sorties by using the receding horizon control strategy with 3receding horizons.Compared with the existing FCFS strategy, the proposed model is able to optimize the multi-runway sequencing problem of arrival and departure flights more dynamically, and the total delay cost reduces more efficiently and the runway resource could be utilized more evenly.More>

2015, 15(2): 70-78. doi: 10.19818/j.cnki.1671-1637.2015.02.008

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Sales process optimization model of voyage capacity for container line

YIN Ming, SHI Heng, JIN Jia-huan

Abstract: On the basis of species evolution and symbiosis theory, the Cobb-Douglas production function was used to describe the whole demand of shipping market, the purchasing behavior of customer was taken as starting point, the maximum revenue was taken as the operation target of container line, the carrying capacity and freight rate based on time series were taken as decision variables, and the sales process optimization model of voyage capacity for container line was set up.The algebraic transformation means such as Taylor formula and least square method were employed to transform nonlinear programming problem to linear programming problem.The calibration and sensitivity analysis of key parameters were carried out, and MATLAB software was used to perform the simulation verification.Simulation result indicates that when thecarrying capacity of single line is 10⁴ TEU, the container line can sell 7 534-9 966 TEU and obtain1 233 158-12 915 936 USD by using the regular sales scheme.By using the proposed model, the container line can sell 9 915 TEU and obtain 15 111 975 USD, and the revenue increases by 17%at least.When the carrying capacities of two lines are both 10⁴ TEU, the two lines can sell 9 920, 9 947 TEU and obtain 14 241 771, 9 737 528 USD respectively by using the proposed model, and Nash equilibrium is achieved.When the carrying capacities of three lines are all 10⁴ TEU, the three lines can sell 8 289, 5 526, 6 034 TEU and obtain 6 755 755, 6 119 906, 4 377 758 USD respectively by using the proposed model, and Nash equilibrium also is achieved.Obviously, the proposed model can describe the sale situations of voyate capacities for multi-container lines and exhibit the significant optimization effect.More>

2015, 15(2): 79-89. doi: 10.19818/j.cnki.1671-1637.2015.02.009

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Selection game model of air service provider based on corporate social responsibility

WANG Gui-hua, LI Nan

Abstract: The concept of corporate social responsibility was proposed, and the performance level and performance strength of corporate social responsibility for air service provider were redefined.The game case between the core enterprise of supply chain and air service provider was divided into four types, and the selection game model of air service provider based on corporate social responsibility was set up.The critical cooperation intentions of short-term cooperation and longterm cooperation for the core enterprise of supply chain and the critical performance probabilities of short-term cooperation and long-term cooperation for air service provider were calculated, and the relationship between the performance level of corporate social responsibility and the selection of air service provider was analyzed.Analysis result shows that when the performance level ofcorporate social responsibility for air service provider is 0.5, the core enterprise of supply chain requires that the performance probability of corporate social responsibility for general air service provider should be over 40%, and the performance probability of corporate social responsibility for strategic air service provider should be over 80%.When the cooperation intention of core enterprise for supply chain is over 41.67%, the general air service provider will actively perform the corporate social responsibility, but only when the cooperation intention is over 83.33%, the strategic air service provider will actively perform the corporate social responsibility.When the performance level of corporate social responsibility for air service provider is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 respectively, the core enterprise of supply chain requires that the performance probability of corporate social responsibility for strategic air service provider should be over 94.6%, 90.0%, 86.2%, 82.6%, 80.0%, 77.5%, 75.3%, 73.3%, 71.6% respectively.Compared with the traditional method, the proposed model not only defines the specific requirements between general air service provider and strategic air service provider, but also reveals the essential relationship between the performance level of corporate social responsibility and the selection of strategic air service provider.More>

2015, 15(2): 90-99. doi: 10.19818/j.cnki.1671-1637.2015.02.010

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3Dbuffer zone creation method of urban rail transit

ZHANG Wen-sheng, JIE Qian, ZHU Ji-jun, ZHANG Bing-zhe, JI Qiang, LI Jian-chun

Abstract: In order to solve the problem that the existing GIS buffer algorithm can not create the3 Dbuffer zone of urban rail transit, octree was adopted as a fundamental data structure for creating the 3Dbuffer zone.The 3Dsolid information of urban rail transit was stored by using linear octree encoding, and the analysis of 3Dbuffer zone was transferred into the spatial analysis of octree nodes.The topology of octree nodes was analyzed, and a new algorithm, i.e.0-1 swapalgorithm, was proposed for linear octree neighborhood analysis.The boundary nodes of rail transit were identified by using the 0-1 swap algorithm, and the directions of boundary nodes were determined.The 3Dbuffer zone of rail transit was created by using boundary nodes.A new3 Dbuffer zone creation method of urban rail transit was formed based on linear octree.The boundary nodes of straight tunnel, curved tunnel, straight viaduct and curved viaduct were created by using the 0-1swap algorithm, and the result was compared with that of conventional algorithm and classical Xiao' s algorithm.The 3Dbuffer zones of double-arch tunnel, single-arch tunnel and viaduct were created by using the proposed method, and the number of octree nodes extracted from the different structures was counted and compared with the number of raster nodes of traditional structure.Analysis result indicates that compared with the conventional algorithm and the classical Xiao' s algorithm, the elapsed times of boundary nodes creation for straight tunnel, curved tunnel, straight viaduct and curved viaduct are minimum by using the 0-1swap algorithm, and the values are 5, 7, 10, 18 ms respectively.The time complexity reduces from second order to first order by using the 0-1swap algorithm.For the 3Dbuffer creation method based on linear octree, the memory spaces of octree data structures are 7.26%, 3.64% and 3.72% of the spaces of raster structures when the 3Dbuffer zones of twin-arch tunnel, singelarch tunnel and viaduct are created.Therefore, the 3D buffer zone creation method greatly reduces the number of analysis nodes, and improves the efficiency of creating the 3Dbuffer zone.More>

2015, 15(2): 100-108. doi: 10.19818/j.cnki.1671-1637.2015.02.011

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Cascade AdaBoost pedestrian detector with multi-features and multi-thresholds

CUI Hua, ZHANG Xiao, GUO Lu, YUAN Chao, XUE Shi-jiao, SONG Huan-sheng

Abstract: In order to meet the practical demand for pedestrian detection with high speed, high accuracy and strong robustness, in view of the poor quality and unapparent local image features of traffic videos, some simple pedestrian features were chosen for pedestrian detection.Besides rectangle degree, ratio of height to width, shape complexity, normalized width, and pedestrian area, head density was applied because it is a simple local feature and has strong robustness for occlusion interference.Considering the size changing of pedestrian in the image, region division strategy was introduced into image region division.An improved training algorithm based on the minimum principle of classification error and the maximum principle of positive sample classification rate was implemented by considering both high detection rate and low false detection rate, thus several single-feature AdaBoost pedestrian detectors with multi-thresholds were obtained.To optimize the detection performance of cascade pedestrian detectors, the cascade rulewas obtained in term of the contribution rate.The contribution rate was defined by weighing detection performance and detection speed.The cascade order was the detectors based on ratio of height to width, normalized width, rectangle degree, pedestrian area, shape complexity and head density.The pedestrian detectors were sequentially cascaded according to the cascade order, thus a cascade AdaBoost pedestrian detector with multi-features and multi-thresholds was constructed.The proposed pedestrian detector was tested by using 3traffic scenes, and compared with singlecascade-level AdaBoost pedestrian detector and 2existed cascade AdaBoost pedestrian detectors.Analysis result indicates that in 3traffic scenes, compared with the other pedestrain detectors, the proposed pedestrain detector has higher detection rate, higher detection speed and lower false detection rate, the minimum detection rate is 96.70%, the maximum false detection rate is0.67%, and the detection time is less than 5s.So the detector satisfies the real-time and reliable requirements of pedestrian detection in traffic scene.More>

2015, 15(2): 109-117. doi: 10.19818/j.cnki.1671-1637.2015.02.012

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AdaBoost-Bagging vehicle detection algorithm based on multi-mode weak classifier

WANG Hai, CAI Ying-feng, YUAN Chao-chun

Abstract: Focusing on the problem that the vehicle detection rate of existed vehicle detection algorithms is lower in real complex road environment, a vehicle detection algorithm was proposed, in which multi-model weak classifiers were integrated into strong classifier by using AdaBoost-Bagging method.In the algorithm, discriminative model could generate a fine decision boundary by using more features, and generative model could eliminate negative examples by using fewer features.To combine the advantages of discriminative model and generative model, discriminative classifier with Haar feature and generative classifier with HOG feature were built.Combined with AdaBoost algorithm, AdaBoost-Bagging strong classifier was obtained by using Bagging algorithm that is an integrated learning algorithm with strong generalization ability.Vehicle detection algorithm was tested based on Caltech1999 dataset and real road images.Test result indicates that compared with sole mode weak classifier, AdaBoost-Bagging strong classifier maintains superiority in classification ability and processing time, its high detection rate and low false detection rate are 95.7%, 0.000 27% respectively, and the detection time of each frame is 25 ms that is less.Compared with the traditional cascade AdaBoost classifier, the detection time of the AdaBoost-Bagging strong classifier increases 12%, the training time increases 30%, but the detection rate increases 1.8%, and the false detection rate decreases 0.000 06%.The proposed algorithm is better than other vehicle detection algorithms, including Haar featurebased AdaBoost classifier, HOG feature-based SVM classifier, HOG feature-based DPM classifier, and has better vehicle detection effect.More>

2015, 15(2): 118-126. doi: 10.19818/j.cnki.1671-1637.2015.02.013

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