Abstract:In order to study the effect of the size of coral coarse aggregate on the mechanical properties of coral concrete, this paper carried out continuous grading of coral concrete with 5-10, 5-20 mm and 5-31.5 mm under three water-cement ratio conditions of 0.50, 0.40 and 0.33. The research results show that the fluidity of newly mixed coral concrete is significantly affected by the aggregate particle size, and the larger the aggregate particle size is, the worse the fluidity will be. The main reason is that its bite-and-lock action is not conducive to the flipping of the aggregate, which reduces the liquidity of the fresh coral concrete. Moreover, particle size has a certain influence on the destruction process of coral concrete, which is mainly reflected in the amount of aggregate penetrating the failure at the failure surface, but the difference in the final failure form is not obvious. Large-size coral aggregate is conducive to enhancing the resistance strength of coral concrete under the condition of low water cement ratio.The irregular arrangement of coral -debris strip characteristic particles shows a certain bridging ability when the strength of cement mortar is low, and the enhancement effect gradually decreases with the increase of the cement motar strength.

Abstract:A double truss composite beam is a new structure that connects two single truss composite beams A and B through a transverse connection system. In order to understand the mechanical performance, deformation capacity, failure mechanism and internal force of each member of the composite beam distribution rules, etc. Design and make test specimens. Through static loading test of A beam of test beam, its displacement, longitudinal strain along the cross-section height, longitudinal strain at the top of concrete slab, axial strain of oblique webs, and the axial direction of transverse coupling system were analyzed. Strain changes with load development. The same specimen model was established and processed by ABAQUS finite element analysis software, and the experimental research results were compared to verify the rationality of the model. The research shows that the composite beam has a good bearing capacity and deformation capacity when a single symmetrical load is applied; the failure mode is A-frame bending failure accompanied by punching and shear failure of the tensioned web rod nodes, and B-frame only oblique web rods receive the axis The force has a small effect; the shear lag coefficient reaches its peak at the ribs, indicating that the stress distribution at the beam ribs is the most uneven. The longitudinal influence range of the coefficients is only near the loading point, and the deformation is concentrated in the middle region. In addition to the axial force of the lower chord The bending effect has a greater influence on the force of the rod, which cannot be ignored.

Abstract:As an important control index of expressway subgrade, resilient modulus is often based on the static characteristics in the current design method, which is inconsistent with the actual situation. It is of great significance to establish the control method of resilient modulus of subgrade based on the dynamic characteristics of subgrade for the construction of expressway with high quality and good road performance. In this paper, the dynamic deformation characteristics of highway subgrade are studied through laboratory tests and finite element simulation. The variation law of dynamic deformation of subgrade structure with loading times is analyzed, and the relationship between dynamic deformation of subgrade and resilient modulus of subgrade is established. From the point of view of dynamic deformation, the requirement of resilient modulus of expressway subgrade is put forward. The research results may provide guidance for the control standard of resilient modulus of expressway subgrade.

Abstract:In order to overcome the difficulty that the value of testing coefficient in traditional load test evaluation has been rough for a long time and cannot adapt to the current evaluation of bridge bearing capacity, and to improve the accuracy of theconstant value range of bridge testing coefficient, the measured value of testing coefficient of a large number of prestressed concrete small box girder is taken as the statistical sample.The testing coefficient of bridge bearing capacity evaluation was studied and optimized by using the probability statistical method. The selection principle of the statistical samples and the refining constant range of bridge testing coefficientwere put forward.The results show that the principle of sample selection determines the dispersion of test data. The range of the testing coefficient of different structural parts is different, and the value of the testing coefficient according to the structural parts can obviously improve the accuracy of the testing coefficient constant. The research can promote the development and perfection of the bridge load test.

Abstract:Relying on a slope project in a reservoir area, through on-site hydrogeological survey and laboratory tests, to master the geotechnical engineering properties of the bank slope, combined with dry and wet cycle tests, theoretical analysis and numerical simulation software, to study the water storage period of the project and the water level after operation Reservoir bank slope stability under dynamic ups and downs. The results show that the groundwater infiltration line is "concave" at high water levels and "convex" at low water levels. As the water level of the reservoir area rises, the stability of the slope will also increase, and when the water level gradually falls, the stability of the slope will decrease, and eventually the stability of the slope will be lower than that of the slope that has not experienced the change of water level. The water level in the reservoir area can be regarded as the safe water level range between the normal storage level of 30m and the highest storage level of 36m. This study can provide a reference for the slope protection of the reservoir area and the water level scheduling scheme in the reservoir area.

Abstract:In order to realize the recognition and diagnosis of process faults, this paper uses CapsNet model to train data. Firstly, using the spatial characteristics of the network model，the training data was characterized and normalized in the form of vectors. Then，a convolution operation was performed to classify the faults on the dynamic consistent routing update. Finally，the reconstitution module was added to modify the input data matrix， reduce the loss error and make the network converge quickly. At the same time, feature visualization wasper formed on each layer of the network, and the changes in the feature map of each layer were clearly seen. The experimental results show that the process fault recognition performance of this model is better than other neural network models.

Abstract:In order to solve the problems in traditional convolutional neural network -based handwritten digits recognition, such as the computation overflow and high demand of computer hardware caused by the exponential function operation of Softmax, a support vector machine (SVM) handwritten digital recognition method based on the feature extraction of convolutional neural network is proposed. And, in order to improve the recognition accuracy of handwritten digits, a particle swarm optimization method based on the fitness function in the sense of K -CV is designed. Experimental simulation based on Semeion and MNIET handwritten digits shows that the method proposed in this paper can achieve higher recognition rate than the traditional methods.

Abstract:Aiming at the problem that many feature extraction algorithms for visual odometry have large deviation of motion information due to uneven corner distribution, a corner extraction method based on Gaussian Pyramid is proposed. Firstly, the algorithm adopted the Gaussian Pyramid algorithm to compress the image scale, compressed the texture in the area of rich texture and aggregated texture in the area of sparse texture. Then, the small-scale top diagram was obtained and the Shi-Tomasi algorithm was used to extract the corners of the top graph for rough feature location. The information was mapped back to the original graph with rich details for accurate corner positioning, and the feature information of the picture was obtained. Finally, the Pyramid LK optical flow method was used to track the corner points, and the motion information is obtained according to the geometric constraint model of camera polar line. In this paper, the KITTI data set was used to compare with the original Shi-Tomasi, Harris, Fast Algorithms. The results show that the algorithm can effectively improve the uniformity of corner distribution and improve the accuracy of motion information recovery of visual odometry.

Abstract:The relationship between flight fuel consumption and its influencing factors is analyzed by using fuel consumption as an environmental indicator of civil aviation flight operations. By comparing with the fuel consumption estimation method of the European Environment Agency (EEA), it is found that the planned fuel consumption of airlines is generally higher than that of EEA, and then the impact of aircraft types, route distances and load on the planned fuel consumption of airlines was studied. In addition, the difference in fuel consumption between full-service and low-cost airlines was compared. The results show that the longer the route distance and the larger the size of the aircraft, the higher the fuel efficiency of the flight. The fuel efficiency of different types of airlinesis significantly different.The fuel efficiency of full-service airlines is lower than that of low-cost airlines.

Abstract:This paper designs a new type of test bench that can detect photoelectric and Hall two different speed sensors. The test bench consists of two parts: hardware and software. The hardware part mainly includes industrial computer, frequency converter, AC asynchronous motor, signal conditioning board, PCI high-speed data acquisition card, etc.; the software part mainly uses the VC++ development language under Microsoft Visual Studio 2010, and processes the data collected by the high-speed data acquisition card. In this software, the speed sensor output signal is converted into the corresponding speed value display according to the signal period and the wheel diameter value; at the same time, the waveform diagram of the output signal is also displayed in real time. In addition, the signal period, duty cycle, and phase difference of the two signals are also calculated. The performance of the speed sensor is judged by comparing the set speed with the measured speed and the phase difference and duty ratio of the output waveform. Taking the TQG15BL photoelectric speed sensor as an example, it is verified by experiments that the designed test bench has good stability and real-time performance, and the detection accuracy can reach 0.2%.

Abstract:The booming of second-hand goods has driven the rise of the C2C reverse logistics platforms. However, the trading difficulty of commodities and the residual value of goods in the C2C reverse logistics platform are rarely studied. In this paper, the commodity utility, the multiplying of the difficulty of commodity trading with the residual value of goods, is introduced. Based on the Amstrong’s bilateral market model, the pricing model of C2C reverse logistics platform in two kinds of markets are studied, i.e. the monopoly market and the duopoly competition market. The research shows that in a monopoly market the platforms increase in commodity utility does not necessarily increase the platforms profit. When the platform is in a duopoly market, there are two situations. First, when the utility of the two platforms has no difference in utility, the profit obtained by the platform is related to the externality coefficient of the network between the two groups. Second, when there is difference in the utility of the two platforms while there is no difference in commodity utility of the platforms and there is no difference in goods obtained by the seller and the buyer, the profit obtained by the platform increases monotonouslyin a certain range with the utility difference between the two platforms.

Abstract:During the reconstruction and expansion of the expressway, the upstream transition zone was set up to ensure the smooth transition of vehicles from the closed lane to the open lane. In this paper, traffic flow operation data of 7 construction schemes of Binlai expressway were collected on the spot, including road widening, bridge widening, interchange reconstruction, lane passage by using the road of opposite side，roadbed elevation, flyover and road to bridge. Single factor analysis of variance showed that there was no significant difference in headway and running speed between interchange reconstruction area and lane passage guide zone. Through the UC-win/Road driving simulation experiment, it is verified that the theoretical calculation results of the length of the upstream transition zone of the three construction schemes of road widening, bridge width and interchange reconstruction meet the requirements of the simulation experiment. In the actual setting, the length of the upstream transition zone of the leading road can be calculated according to the acceptable gap theory.

Abstract:Bearings usually work in the complex noise environment, which makes the time-domain vibration signal easy to be polluted by various noises, thus misleading the diagnosis results.To solve this problem, a method combining a one-dimensional (1-D) denoising convolutional autoencoder (DCAE) and a (1-D) convolutional neural network (CNN) is proposed. In order to simulate the real noise environment, Gaussian noise with different signal-to-noise ratio was added to the original vibration signal. 1D-DCAE was used to denoise the original signals, and then the denoised signal was used for 1D-CNN fault dignosis.1D-DCAE was built based on full convolution network (FCN) and the pooling layer was discarded to improve the anti-noise capability. The results show that FCN-based 1D-DCAE has better noise reduction effect, and the improved model can adaptively diagnose faults of various noise environments.

Abstract:In order to reduce the aerodynamic drag and noise of high-speed trains in operation, improve the train operation efficiency, save energy consumption and improve the comfort of passengers, the convex hull non-smooth surface drag reduction technology is applied to the field of high-speed trains in this paper. Taking the CRH3 high-speed train as the research object, the turbulence characteristics are controlled by adding convex hulls at the head and tail of the car body to achieve the effects of drag reduction and noise reduction. Firstly, the simplified model of non-smooth surface CRH3 high-speed train was built by PRO/Engineer. The model was divided into unstructured grids by ICEM CFD software. Then the fluent fluid simulation was used to simulate the train with steady-state running speed of 300 km/h based on the standard model to calculate the air resistance. Finally, the train with good aerodynamic performance is simulated by using broad band noise. The results show that the convex hull array structure with a pitch of 460 mm, a radius of 40mm and a height of 10 mm around the wind screen has a positive effect on reducing the aerodynamic drag. The resistance value is 3 715 N, and the drag reduction rate is 1.77%. The parameter convex hull is non-smooth and has a general noise reduction effect on the upper edge of the train skirt, with the maximum noise reduction rate of 1.72%, and noise is added to the nose and the top of the car. It can be seen that by adding a convex hull in the head car, the turbulence characteristics of the boundary layer can be changed to reduce the aerodynamic drag of the train and reduce the aerodynamic noise at some positions.

Abstract:In order to study the fuel consumption characteristics of small vehicles at the mountain road curve, the traffic flow on the road curve from Fuzhou Forest Park to Guling mountain area is taken as the research object. The video data of vehicle up and down were taken by UAV, and the driving characteristic data of small vehicles were collected by tracker; the three-dimensional relationship of average travel speed, section position and vehicle specific power (VSP) were fitted by MATLAB; according to the relationship model and the instantaneous average fuel consumption rate of small cars, a curve fuel consumption model was established, and the fuel consumption of small cars in the process of turning was calculated under different average travel speed values. The results show that the relationship between the average travel speed and the fuel consumption satisfies the cubic polynomial. The curve fuel consumption model can predict the fuel consumption of the small car in the curve to a certain extent, which has a certain reference value for the implementation of energy saving and emission reduction strategies.

Abstract:According to the characteristics of different correlation and importance between the variables of transformer state evaluation, the weighted Mahalanobis distance is introduced into the traditional multivariate statistical control chart based on Mahalanobis distance, and a transformer evaluation method based on the variable weighted multivariate statistical process control is designed. This method combines the weight of transformer state variable given by association rule method, and uses the wave detection ability of multivariate control chart to transform the multivariate real -time monitoring data corresponding to various faults of transformer into a test statistic, and then evaluates the operation state of transformer. The example analysis of the current circuit overheat fault shows that compared with the current transformer condition evaluation standard, the method has faster fault detection speed; the retrospective detection of the sample data of known faults shows that the method has higher fault detection rate.

Abstract:Wind power forecasting is vital to the stable operation and economic dispatch of power system. In order to fully mine the effective information in historical data to improve the accuracy of short-term wind power prediction, a short -term wind power prediction method based on convolution neural network (CNN) and long short-term memory network model(LSTM) is proposed. The effective information was extracted by CNN sequence feature extraction ability, and the data was input to LSTM network after other information was removed. The problem of gradient dispersion could be solved by keeping longer effective memory information, which made up for the lack of instability and gradient disappearance when the LSTM network model was faced with a long sequence. The results show that the method proposed is more accurate than the back propagation neural network and LSTM network.

Abstract:In order to improve the accuracy of semantic segmentation of low -illumination images, an edge en hanced semantic segmentation model (EESN) based on RPN is proposed. Firstly, higher-order semantic features of images were learned by using a deep residual network, and the region proposals were quickly generated by RPN. Secondly, a fusion algorithm was designed to fuse the region proposals and eliminate the repeated candidate regions. Finally, low-illumination edges were searched by the edge search box, and their features were enhanced by using the local enhancement algorithm with low distortion. EESN was used in semantic segmentation of Pascal VOC12 dataset and Cityscapes dataset, and 81.2% and 67.6% of pixel intersection-over-union (mIoU) on these two datasets were obtained. The experimental results also demonstrate that EESN has good segmentation performance for images with low illumination edge.

Abstract:It is found that there is a layer of block stone at the bottom of Liangzhu ancient city wall. In order tofind out the purpose and the effect of the bedding stones, this paper uses GeoStudio software to carry out the fi-nite element calculation, and quantitatively analyzes the stability of the bedding stoneson enhancing the stabilityof the city wall and the consolidation of the drainage. And the three aspects of sedimentation and horizontal de-formation are reduced. The calculation results show that after the pavement of bedding stones, the surface of thefoundation forms a hard shell layer with higher strength and higher modulus, the anti -slip capability of the citywall is enhanced, the stability safety factor of the slope is improved by about 10%- 19%, and the average consol-idation degree of the foundation can be increased by 10.8%-14.9% after the laying ofbedding stones for 100days. The filling speed is allowed to be increased from 8 days to 6 days; the laying of bedding stones can alsoplay a stress-diffusion function, reducing the maximum settlement of the foundation by 47%, and the maximumhorizontal displacement by 39.2%, which is conducive to the reduction of the filling earthwork volume.

Abstract:The reduction of strain resistance caused by different compression variables and reverse strain of damping winding coupling material of hydro-generator set is studied, which is called Bauschinger effect, abbreviated as BE. The influence of different compression strain variables on damping winding connector BE was discussed. Through different compression strain compression and tension experiments, the optimal Baussinger extremum of damping winding copper connector was obtained. The results show that large compression variables have an effect on BE. With the increase of pre -deformation, the Bauschinger effect value changes. When the pre-deformation is 3%, the Bauschinger effect value reaches the extreme value. In addition, when the deformation is increased, the Bauschinger effect value ecreases, and 3% is the optimal shape variable, namely, the failure limit value of damping winding.

Abstract:In the traditional differential equation solution, the multi-region spectral method only constructs the approximation scheme of the equation independently in the local element, and different elements exchange information by penalizing the boundary or the numerical flow function on the boundary, which has good flexibility and high precision in the selection of the basis function and the generation of the grid. In this paper, the numerical solution of Maxwell Differential Equation is studied based on multi-region spectral method. In order to further reduce the computational cost of solving the equation, various difference numerical flux formats are introduced. By use of the upwind flux, the scale of the hybrid model supported by the format is reduced. The non-physical eigenvalues cannot be removed and the spectra are clearly separated, which makes it possible to separate the physical mode from the mixed mode. The algorithm is suitable for arbitrary mesh generation with high precision and high efficiency, and the effectiveness of the algorithm is verified by numerical examples.