Abstract:By conducting a series of wind pressure measurement wind tunnel tests， the characteristics of the extreme area-averaging wind pressures on the cladding of a building with a rectangular cross-section were studied. The test results were compared with relevant standards of Load Code for the Design of Building Structures （GB 50009—2012）. The influence of areal size， horizontal scale and vertical scale of forced areas were discussed， and more reasonable scale parameters were suggested for size reduction coefficients （SRCs） of area-averaging wind pressure. The results indicate that extreme wind pressure gradually declines with the size of forced areas increasing. When the full-scale area reaches about 50 m2， the SRC of positive extreme area-averaging wind pressure is close to about 0.9， while that of negative extreme area-averaging wind pressure is close to about 0.8. The wind-load reduction method of building structure load code in China will lead to an underestimation of wind pressure extreme value， especially in the most unfavorable positive pressure. It is not appropriate to describe the variation of the reduction coefficient by taking the area of acting surface as the size parameter. It is，therefore， suggested that comprehensive size parameters， b0.85h0.15/B， of the horizontal dimension， b， vertical dimension， h， of the acting surface and the width， B， of the windward surface of the whole building be used to determine the SRCs of the surface wind pressure extremum of the cladding.

Abstract:In order to study the load-displacement relationship of the timber bolted connection with slotted steel plate， monotonic tests were performed on 24 specimens in the direction parallel to timber grain， considering the bolt diameter， the dowel bearing length and the slender ratio. The experimental results show that the connection undergoes the elastic stage， elastic-plastic stage， plastic-developing stage and failure， performing well in terms of deformation. Based on the curve fitting， a two-parameter （i.e.，strength and elastic stiffness） mechanical model was proposed and theoretical formulas of the two parameters were derived. Finally， with the theoretical formulas and mechanical model， a calculation was conducted to obtain the load-displacement relationship curves of the specimens， which was found to be in good agreement with the test results.

Abstract:The influence mechanism of surface surcharge position on tunnel lateral deformation in soft and hard soil is studied by using the scale model test. Considering different surcharge position and tunnel traversing soil layer properties， the changes of ellipticity， the joint opening， and the additional earth pressure of tunnel segment during the graded loading-unloading process are measured. The test results show that when the load is the same， the tunnel ellipticity decreases rapidly first and then tends to smoothen with the increase of eccentricity of surcharge， the ellipticity of the tunnel in soft soil layer is larger than that of the tunnel in hard soil layer due to loading， and the decrease of tunnel ellipticity in soft soil layer is more obvious with the increase of eccentricity. Increasing the eccentricity of surcharge can effectively reduce the opening of the tunnel joint. The deformation mainly occurs in the left and right shoulder and the top joint of the tunnel when the load is directly above， and mainly in the shoulder and the top joint on the opposite side of the load during eccentric loading. Under the action of surcharge， the earth pressure of the tunnel in the sandy soil layer is uniformly distributed， while that in the soft soil layer is mainly concentrated in the horizontal direction. With the increase of eccentricity， the earth pressure decreases gradually and the main concentrated point shifts to the oblique section of the opposite side of the load. Finally， based on the results of finite element parameter analysis， the protection suggestions on the surface surcharge in the operating tunnel are proposed.

Abstract:Due to the diversity of rural space， value， and governance， the multi-compliance village plan is bound to face multiple difficulties. In order to avoid impractical， invalid， and unbalanced planning， in the context of rural revitalization， the spatial planning of national land in rural areas must take into account the practicability and validity. The practical village planning should make the index system practical， the governance strategy practical and the implementation path practical， the valid village planning should be valid rigid conduction， valid planning organization and valid dynamic blueprint. To encourage the practice of rural construction in accordance with local conditions， attention should be paid to the reconstruction of rural governance in accordance with the local conditions，to cultivate new rural management organizations in line with the local conditions， to construct a multi-symbiotic spatial system， and to inject reproduction capacity into the rural society in practical and valid village planning.

Abstract:Nowadays， while the flood problem is becoming more serious， there are certain limitations in the practices of urban design in China（such as Sponge City） from the perspective of water. Based on the clue of the “relationship between water and city ”， this paper proposes 3 strategies， “Separation”， “Interval”， “combination”， and their internal and external causes， by refining and discriminating the abstract structural models of 3 ideal cities in ancient China and 4 construction practices in modern Dutch cities， and then analyzes the water problems faced by the cities in different times and the livable reconstruction strategies. It shows that the successful design practice of urban design from the perspective of water is the comprehensive application of the various design strategies under the structural model logic of the relationship between water and cities.

Abstract:In the emerging leisure and entertainment space of cruise ship，the user's sensory and experience contribute to the realization of space value. Traditional studies mostly focus on promoting the linterior decoration but ignoring the psychological perception of tourists. In the analysis of the perception of cruise space experience， taking Chinese coastal passengers as the research object， conducted a cruise space experience questionnaire survey was conducted on the “Venezia ”， cruise ship. Based on the collected data on experience perception model was built by using exploratory factor analysis and the structural equation model to explore the factors affecting experience perception in cruise space and the relationship with satisfaction. From the simulation path fitting results， it can be seen that the physical environment， the aesthetic perception， the cognitive experience， the spatial attributes， and the overall evaluation are positively significant， and show a decreasing trend. It can be concluded that the cruise space experience has a very important impact on overall satisfaction， affection and re-boarding. When China’s cruise industry is just in its infancy， this paper provides ideas and directions for the future planning and improvement of cruise space.

Abstract:In order to simulate driver's memory effects and fuzzy perception characteristics， a deep learning car-following model was designed based on fuzzy perception time window. Taking 3 s continuous speed， leading-following car speed difference and headway distance as model inputs with a minimum time interval of 0.2 s，the driving memory was simulated. A gated recurrent unit （GRU） network with a single layer of 32 output dimensions could fit the actual data well by training multiple groups of deep learning car-following models. In each input time series data of the model， part of the real car-following state value was replaced by the predicted value of the model as the driver’s estimation of the scenario， that is， fuzzy perception. The experiment results show that different fuzzy perceptions to the same scenario can produce different car following behaviors， and the heterogeneity of driving behaviors can be simulated， which provide a method for heterogeneous traffic behavior simulation.

Abstract:In order to effectively learn the mixed traffic congestion patterns from the urban expressways and improve the accuracy of short-term travelling speed prediction， based on the convolution neural network， and incorporated with the Inception Module， a short-term travelling speed prediction model was established. The travelling speed information was arranged into two-dimensional matrices which could represent the traffic states， and the features represented by the input time-space travel speed images were learnt. The optimum model was obtained as the result of a systematic neural network design and training process， with the ability to automatically recognize multi-scale mixed traffic congestion patterns and extract high-dimensional features of the traffic data. Besides the regression analysis method as well as the gradient magnitude similarity deviation indicator was introduced to conduct a comprehensive evaluation. The case study shows that the proposed model outperforms other models in learning the temporal/spatiotemporal features from traffic data with a high prediction accuracy， which can be further applied to making short-term prediction for other traffic parameters.

Abstract:The mode switching time delay of the block mode-communication based train control（BM-CBTC） multi-mode train control system has a great impact on the operation efficiency of urban rail transit. First， this paper analyzed the function and process of mode switching in the BM-CBTC system. Next， it established a mode switching model based on coloured Petri net （CPN）. Then， it studied the real-time performance of mode switching at different BM design operation intervals. The experiments show that the switching time delay increases with the increase of BM design operation interval， and the train operation delay can be within 5 minutes when the BM design operation interval reaches 2 minutes. The established CPN model also offers a reference for the real-time analysis of mode switching in other multi-mode train control systems.

Abstract:In order to verify the safety characteristics of interactive data in the system in the design stage， a safety impact analysis method based on colored Petri nets and the failure propagation model is proposed to automatically analyze the system model and obtain the minimum cut set of input data failure. First， the colored Petri net model of the system is established， and the case is obtained by numerical discretization of the place. The failure behavior function is obtained by unit test of the transition using the use case， and the failure propagation colored Petri net with failure behavior transition is obtained. Then， based on the state space of the colored Petri net model， the failure space generation algorithm and the transition backtracking method are used to realize the transformation from the model state space to the failure state space， and then to failure state tree. The minimum cut set of system failure is obtained by merging and calculating the failure state tree. Finally， through the experiment， the change of the minimum cut set of system failure under different data safety measures is compared， and the effect of security measures on system security is verified. The experimental results prove the correctness and effectiveness of the analysis method.

Abstract:Based on the construction technology of the debonding repairment applied to the high speed railway ballastless track， the interlayer interfaces were simulated by adapting cohesive element based on the bilinear cohesive zone model， and a finite element model of II slab track of China railway track system （CRTS） was established with full consideration of multi-interface bonding properties. The warping features of the ballastless track-slab were calculated and analyzed at the temperature gradient loads from -50 ℃·m^-1 to ＋100 ℃·m^-1 and the temperature change loads from －30 ℃ to 30 ℃， respectively. The results show that within the range of the temperature loads in this paper， under the debonding-repaired condition， the warping modes and the warping extremes of the track-slab are consistent with the normal state， which indicates that the debonding repairment has restored the warping of the track-slab.

Abstract:A small-scale wheel-wheel rolling contact fatigue （RCF） experiment was applied to reproduce the rail RCF crack initiation and wear growth process. Then， according to the experimental conditions， the prediction model was established based on the method for the coexistence of rail rolling contact fatigue(RCF） crack initiation and wear growth. The wear， crack initiation life and the angle of the RCF crack in the rail specimens of the experiment and simulation were compared to verify the method. The result shows that when the crack initiated in the specimen surface during the experiment， 53.8 % of the specimen experiences two wear phases. The average wear growth rate is about 5.83 μm·10^-4 cycles^-1. In the simulation， there are also two wear phases when the crack was initiated. The average wear growth rate is about 5.18 μm·10^-4 cycles^-1 which is about 11.1 % lower than the experimental results. In the experiment， the crack initiation life is about 6×10⁴ to 14×10⁴ cycles. Moreover， the crack length reaches its maximum value when the loading cycles is about 11×10⁴ to 12×10⁴ cycles. In the simulation， the predicted crack initiation life is about 11.1×10⁴ cycles， which is close to that of the specimen with the maximum crack length in the experiment. It is observed that the average value of the angle between the crack mouth and the running direction along the specimen surface is about 45°which is close to that of simulation.

Abstract:The track bed with sparse pile foundation was developed to avoid the excessive settlement of track beds due to long-term cyclic wheel-pressure. To understand the settlement development， a two-year monitoring of an actual tram project in a southern city in China was reported. The results reveal that the settlement of the track bed increased rapidly in the initial stage. The settlement gradually reduced after around one year and tends to be stable after two years. Moreover， based on the explicit cumulative strain model， an equivalent finite element method is proposed for predicting the long-term cumulative settlement of the track bed with sparse pile foundation. A good agreement between the monitored and calculated results demonstrates the rationality. Furthermore， discussions on the bearing mechanism of the track bed with sparse pile foundation are presented.

Abstract:Aimed at the problem that the degradation state of equipment cannot be obtained online for serial production system， a joint optimization model of maintenance、quality control and buffer allocation was proposed. Based on the quality index of the hidden Markov degradation system， an online decision-making strategy for maintenance was proposed. The recursive formula of processing time and completion time was derived， and the buffer allocation model with limited buffer capacity was established. In order to minimize the total cost， a joint optimization mathematical model to decide the optimum quality threshold for maintenance and buffer allocation was established. The Monte Carlo simulation algorithm based on machine state-transition was used to estimate the expected cost of the system and a tabu search algorithm with cellular automatic mechanism neighborhood rules was proposed to solve the model. The numerical experiments verify the validity of the proposed joint optimization model and algorithms.

Abstract:In order to solve the problems of the existing neighborhood search based on critical path， such as too many invalid moves， too much blindness and optimization one objective， a more precise and effective neighborhood structure is designed， including the two-step operation of the same machine movement and the cross-machine movement. Based on which， the corresponding operation movement conditions are given and extended from the optimization of the maximum completion time to multi-objective optimization. Besides， to realize the complementary advantages of local and global search， the algorithm is mixed with the evolutionary algorithm， and the corresponding hybrid algorithm framework is given. Moreover， two internationally used case sets are tested， and the test results are compared with those of other algorithms to verify the effectiveness and efficiency of the proposed algorithm.

Abstract:The submarine groundwater of a series of stratified vertical wells near the coast of Beihai， Guangxi was monitored and analyzed on-site. The monitoring and sampling analysis show that the salinity in the groundwater in Confined I which is close to the seaside is relatively high， and the difference in salinity is mainly affected by seawater intrusion and high-level mariculture. The concentration of SiO₃-Si in groundwater increases from inland to coastal area due to the “salt effect”， and the low content of PO₄-P which may have been caused by the adsorption and removal of iron oxides. The NH₄-N and NO_x-N concentrations in the phreatic layer are higher than those in confined water. The infiltration of high-level aquaculture pond water results in the highest NH₄-N concentration in the nearshore phreatic layer， while NO_x-N is affected by denitrification. The average N / P ratio of groundwater in the studied area is 595.85， and the discharge of groundwater with a high N / P ratio into the ocean will promote the transformation of nutrient structure of plankton from N limitation to P limitation.

Abstract:In order to analyze the genesis and source of Bozhong 19-6 gas condensate reservoir， the genesis and gas-oil relationship of Bozhong 19-6 gas reservoir were analyzed using a series of isotopes， light hydrocarbon parameters， and biomarkers.The results show that Bozhong 19-6 gas field has a low drying coefficient， a heavy carbon isotope， and a maturity distribution of about 1.50 %， representing a hybrid origin and high-mature gas. The content of dicamantane in the condensate from Bozhong 19-6 gas field is high whereas the content of biomarkers is low， showing a characteristic of high-mature oil. This indicates that the cracking degree of normal oil amounts is lower than 20 %. The contribution of natural gas produced from cracking of crude oil is small. The gas in Bozhong 19-6 gas field is mainly formed by kerogen cracking.