Abstract:Based on the theoretical research progress made in the past five decades， this paper sorts out four analysis methods for concrete fatigue， summaries their representative work， discusses their individual advantages and limitations， and points out the importance of physical mechanisms in further research.

Abstract:Considering the correlation among the failure modes of the multiple control monitoring points from the existing long-span bridge girder， a novel optimal R-vine Gaussian copula data fusion method for failure probability analysis is presented. Based on the extreme strain information， an optimal R-vine Gaussian copula model considering the correlation among the failure modes of the multiple control monitoring points is built by combining the corresponding performance functions， the bivariate pair-Gaussian-copula model and the optimal R-vine model. Further， with the first order second moment method， the failure probability analysis of the existing long-span bridge girder is conducted considering the correlation among the failure modes. The feasibility and application of the method proposed is compared with the other analysis methods based on the monitoring data of the existing bridge. The results show that the optimal R-Vine Gaussian copula information fusion method for the failure probability analysis of long-span bridge girder considering the correlation among failure modes is more reasonable.

Abstract:To solve the problem of dynamic changes in risk assessment of large-scale bridge engineering， the structure-risk decomposition identification method was used to complete the preliminary identification of risk elements. Beside the DEMATEL was introduced to identify dynamic assessment risk elements， and the risk element transmission network was extracted. Moreover， Bayesian network and Genie software were applicated together with the reverse reasoning and sensitivity analysis to perform Bayesian probability calculation on the risk element transfer network， for obtaining the main risk element transfer chain and the key risk elements. This method was used to conduct the dynamic risk assessment of the whole construction process of the Wufengshan Yangtze River Bridge. The results show that 234 dynamic risk elements， 104 key risk elements and the corresponding main risk chains were identified in the whole bridge construction. The probability values of “high-speed railway driving safety”before construction and after the completion of the main girder were found to be 0.065 2 and 0.009 1 respectively. The related key risk elements are uneven settlement of caisson， linear deviation of main cable and so on. The main risk chain is uneven settlement of caisson →position change of anchor body → displacement of anchoring system → deviation of main cable line shape → uneven deformation of sling → line shape change of main girder → insufficient smoothness of railway bridge surface → driving safety of high-speed railway.

Abstract:To better understand the characteristics of rip current caused by crossing irregular waves，an experimental study of rip current caused by intersecting irregular waves over barred beaches was conducted. The barred beach without rip channel was adopted to eliminate the inconsistency of coastal topography caused by the rip channel，so that the rip currents was mainly controlled by the node points of waves. The driving force of the rip current is mainly the mean water surface pressure gradient pointing to the node，while the radiation stress caused by wave height contributes little due to the change of wave height along the break zone. The magnitude and range of the driving force are affected by the period. The location and width of rip currents are controlled by the wave node points. The cross-wave field forms an alternate circulation system and large-scale vortex in the alongshore direction. The circulation system includes the rip currents around the wave node points，the onshore current around the wave anti-node points，and the longshore feeder currents from the anti-node to the wave node points.

Abstract:Based on the wind speed records from the 356m high Shenzhen Meteorological Gradient Tower（SZMGT）， this paper analyzes the vertical distribution of wind characteristics during the invasion of the super typhoon Mangkut. The results show that： the mean wind speed profile exponent of the upstream surface of the SZGMT is 0.238， which is slightly higher than that of the Load Code for the Design of Building Structures （GB50009-2012） for terrain category C. The longitudinal turbulence intensity distribution is close to the recommended value of GB50009-2012 for terrain category D. The three-direction turbulence intensity ratio is smaller than the recommended value of Highway Bridge Wind Resistance Design Guide， and increases with the increase of height. The gust factor is highly linear with the turbulence intensity， and the fitting result of the peak factor is close to 2.5. The observed longitudinal turbulence integral scale profile is slightly larger than the recommended value of AIJ 2004 and ASCE7-2010， and the longitudinal wind speed spectra are consistent with Von Karman spectrum.

Abstract:In order to reveal the operational characteristics of traffic flow on underground expressways， a car-following model based on the data-driven method was proposed by using the high-precision vehicle trajectory data obtained by driving simulator， and was calibrated and verified. First， the driving simulation experiment was conducted according to the scenario model of the east section of the North Cross Passage in Shanghai to obtain the car-following data. Next，the support vector regression （SVR） method was selected to establish the car-following model， into which the driving behavior constraints were introduced.Finally， the improved SVR-based car-following model was calibrated and verified by using the experimental data. The results show that the support-vector-regression-based car-following model considering driving behavior constraints can well describe the car-following behavior on underground expressways. The model possesses a great transplantability， which has a high accuracy on other underground expressways. The car-following model proposed in this paper can quantitatively analyze the interaction of vehicles on underground expressways， and provide the basis for traffic simulation and risk research.

Abstract:Adhesive and self-healing properties are two inherent properties that should be considered when evaluating the durability of asphalt materials. In this paper， the binder bond strength （BBS） test is applied to evaluate the effects of five representative modifiers at varying dosages on the adhesive and self-healing properties of asphalt. Moreover， the four-point beam （4PB） fatigue test with a healing interval period is conducted and correlated with BBS testing results. It is found that linear SBS， high-density polyethylene （HDPE） and rubber all have negative effects on the asphalt adhesive strength while only gilsonite can enhance the adhesive property. HDPE， rubber and gilsonite at lower dosages （≤12.0%） can improve the asphalt self-healing property. In addition， the strong correlation of the healing performance between binder and mixture is found， verifying the accuracy of the BBS test in evaluating the healing performance of asphalt materials.

Abstract:The implementation process of rail profile grinding was described. The key links of target profile design， grinding mode design and result acceptance evaluation were analyzed. The design methods of each link were proposed and the relevant computer intelligent design program was developed. The on-site implementation effects were observed and analyzed based on actual cases. The results show that the optimization of the design methods for each key link of rail grinding can greatly improve the pertinence of rail grinding operation. The development of computer intelligent design program can greatly improve the design efficiency and implementation accuracy of rail grinding schemes. After the intelligent design methods were adopted in the Guangtong-Dali Line of Kunming Railway Bureau， the serious wear problems of small radius curve rail and locomotive wheel flange were effectively solved， the results of field test and theoretical analysis are basically consistent. The application of this method can effectively control the wear of rail and wheel， prolong the service life of rail and delay the wheel turning cycle.

Abstract:Based on the consideration of the loading and unloading of twin 40’ quay cranes， the stowage of 20’ and 40’ dry containers and reefer containers， and the influence of ship hatch cover， a mixed integer programming model is established to solve the multi-port main master bay plan problem， whose aim is to minimize the total loading and unloading times of container crane on the route. The bin packing algorithm with over-sized items is designed based on heuristic rules to obtain the stowage plans of 20’ and 40’ containers in the cabin in mixed loading strategy and non-mixed loading strategy. It is found that the non-mixed loading strategy can effectively improve the total loading and unloading efficiency and the stowage model and algorithm can optimize the stowage plan， which generally improves the efficiency by at least 24.5% compared with common quay cranes under equal conditions.

Abstract:Taking the coastal wetland of the Yangtze River Estuary as the research area， the random forest model was used to classify the vegetation of wetland. Besides the vegetation index and water index extracted from Landsat-8 OLI image， the seasonal difference value of vegetation index based on plant phenology characteristics was proposed in this paper as the optimization of feature variables to analyze the spatial characteristics of vegetation distribution in the coastal wetland of the Yangtze River Estuary. Bassd on the vegetation classifications， the multiple linear regression model combined with the field data was used to estimate the vegetation density of the Spartina alterniflora， which was an invasive species occupying the largest area. It is indicated that the proposed multi-temporal data combined with the optimization of feature variable of random forest model can be used to conveniently analyze the spatially vegetation distributions in wetland . Compared with the maximum likelihood classification method， the proposed method in this paper greatly enhances the classification accuracy with an overall accuracy and Kappa coefficient of the classification results increasing from 78.35% and 0.72 to 86.02% and 0.82， respectively. The proposed method is proved to be applicable for solving the problem of “same spectrum for different surface features” in the study of wetland plant community distributions.

Abstract:This paper aims to compare the effects of several home-office strategies to mitigate spreads of infectious diseases in metropolises using simulation approaches， in order to support formulations of pandemic interventions in the post-pandemic period. Taking Shanghai as an example， and based on the current situation of work， residence， and commuting reflected by the mobile phone data， a multi-agent simulation is conducted to simulate the spread of virus across the region. Besides，the influences of several home-office strategies are discussed from the macro， meso， and micro levels. It is found that as the proportion of the home-office population increases， the spread is weakened， the proportions of young people in the infected population decrease， and the proportions of the elderly increase. The farther the personal commuting distance， the closer the home is to the city center， and the closer the work place is to the disease source， the more likely is an individual susceptible and infectious. Long distance commuters have the greatest impact on the spread. Choosing home-office workers based on commuting distance can mitigate the spread more efficiently than random selection.

Abstract:Aimed at the problem that the large number of reference signals for the road noise active control system leads to a heavy computational burden， and the directly constructed virtual reference signals are not highly coherent with the target noise in the vehicle， a method for constructing virtual reference signals utilizing grouping is proposed. First， the vehicle road test is conducted， the vibration acceleration signals collected near the four- wheel positions are selected as the original signals， and the number of virtual reference signals is determined based on the singular value analysis. Then， the original signals with high correlations are divided into a group based on the wheel position， the conversion matrix is constructed by the singular value decomposition for each group of original signals， and the virtual reference signals are constructed utilizing grouping. Finally， a road noise active control model based on the normalized filtered-x least mean square （NFXLMS） algorithm is built to analyze the performance of the virtual reference signals constructed utilizing group in reducing computational complexity and noise reduction. Compared with the original virtual reference signal construction method， this method has greatly reduced the computation complexity and improved the noise reduction effect， which verifies the effectiveness of the method.

Abstract:Due to the highly non-uniform characteristics of the thermal environment of vehicle cabins， the predicted mean vote （PMV-PPD） evaluation method developed from uniform thermal environment cannot objectively evaluate the thermal comfort state of passengers. The evaluation method based on equivalent uniform temperature （EHT） takes into account the response of human body to the heterogeneous thermal environment. In this paper， a coupled simulation model of computational fluid dynamics （CFD） and human thermal physiological model was built， and several approximate models such as EHT and PMV of the passenger compartment with air supply parameters as well as solar parameters were fitted by using the optimal Latin hypercube design method. Then， based on the EHT and PMV evaluation methods， the cabin air supply parameters under different thermal comfort requirements were designed by using the sequential quadratic programming optimization algorithm （NLPQL）. The average skin temperature of human body， the latent / sensible heat transfer rate between human body and the cabin， and the ratio of convective to radiation under the two evaluation methods were compared. It was found that under the same thermal comfort demand， compared with the PMV evaluation method， the air supply state designed based on the EHT method is more inclined to high air temperature as well as a high air-supply velocity.

Abstract:Precise point positioning （PPP） is not affected by the local observation and infrastructure which is beneficial for deformation monitoring. Considering the influence of the ionospheric delay on single-frequency point positioning， the method of the mixed application of the single and dual frequency observations is proposed. However， the single-frequency precise point positioning is affected by the fractional bias of phase observation. The method for introducing the dual-differenced ambiguity into single-frequency precise point positioning is discussed. The data are processed using the method proposed. The results show that the estimated ionospheric delay is higher than 1 cm which can meet the requirement of single-frequency point positioning. It is noticed that the convergence time can be shortened for an average improvement of 7 minutes. The improvements for the single-frequency point positioning in the directions of the North， East， and UP can reach 0.23， 0.14， and 0.21 cm， respectively.

Abstract:The weighted total least-squares （WTLS） adjustment is a rigorous method for estimating parameters in the errors-in-variables （EIV） model. However， the WTLS are not proper for larger data problem in terms of computational efficiency. Aimed at the structural characteristics of the design matrix in the EIV model，a partially weighted total least-squares （PWTLS） algorithm is proposed based on weighted least-squares （WLS） adjustment by weighting the random column of the design matrix. The PWTLS can obtain an exact solution of the EIV model without applying Lagrange multipliers in a straightforward manner. In addition， the PWTLS reduces the dimensions of the cofactor matrix and does not estimate the random error of the design matrix， as this would greatly improve the computational efficiency. Finally， real and simulated examples are used to demonstrate the accuracy and computational performance of the proposed algorithms . The results show that the PWTLS can obtain the same accuracy as the existing seven improved algorithms， but the computational efficiency is significantly improved .

Abstract:Let A be a unital simple C*?algebra such that A has the k?locally almost divisible property （or UCFPn(W(A))=m ）. Suppose that α:G→Aut(A) is an action of a finite group G on A which has the tracial Rokhlin property. Then the crossed product C*?algebra C*(G,A,α) has the k?locally almost divisible property （or UCFPn(W(C*(G,A,α)))=m）.

Abstract:In a graph G = （V， E）， let f be a mapping from vertex and set V to ｛0， 1， 2｝. If every vertex v such that f（v）=0 is adjacent to at least one vertex assigned 2 under f or adjacent to at least two vertices assigned 1 under f， then f is called an Italian domination function of G. The sum of f （v） all over G is the weight of f. The minimum weight is the Italian domination number of G. To determine the Italian domination number of a graph is NP-complete. The upper bounds on Italian domination numbers of P（n，1） and P（n，2） are calculated by constructing recursive Italian dominating functions. The lower bounds on Italian domination numbers of P（n，1） and P（n，2） are proved using the bagging method and the dominating cost function method respectively. Therefore， the Italian domination numbers of P（n，1） and P（n，2） are determined.