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In order to improve the accuracy of respiratory signal to distinguish driving fatigue, the relationship was explored between respiratory signal and driver fatigue state through simulated driving test. The concept of respiratory fatigue node was proposed, and the driver's fatigue state was distinguished based on the respiratory fatigue node. Firstly, the respiratory signals of drivers were collected by simulated driving test, and the Karolinska sleepiness scale (KSS) was used to quantify the subjective self-evaluation of their fatigue degree. Secondly, the percentage of eyelid closure over the pupil over time (PERCLOS) was used as a reference, combined with subjective self-evaluation feedback to calibrate the respiratory fatigue nodes of drivers. Finally, based on the respiratory fatigue nodes, the random tree(RT) algorithm was used to obtain the discriminant model of mild / severe respiratory fatigue change nodes. The results show that the model can identify the driver's respiratory fatigue state more timely and accurately and the accuracy of the screening conditions based on the random tree algorithm for the identification of mild respiratory fatigue change nodes is higher than that of severe respiratory fatigue change nodes. The average recognition errors of mild / severe respiratory fatigue change nodes are 3. 50 min and 3. 66 min, respectively, the prediction accuracy is 92. 09% and 92. 03% respectively. [ABSTRACT FROM AUTHOR]

In the process of silo discharge, the flow pattern of storage material changes constantly, and the pressure of silo wall shows different change rules. To investigate the flow pattern and velocity distribution, dynamic lateral pressure and corresponding overpressure coefficient during the discharge process, discrete element simulation software engineering discrete element method (EDEM) was used to simulate under two different discharge speed conditions, and the dynamic lateral pressure was compared and analyzed combined with the test results. The results show that the flow pattern of the storage material is related to its position by direct observation and overall flow index analysis, and the development process is integrated flow, tubular flow and funnel flow. The EDEM simulation results show that the static lateral pressure value and the dynamic lateral pressure distribution law are consistent with the test results, and the overpressure coefficient error is within a reasonable range. In the whole process of discharge, the overpressure coefficient under the fast velocity condition is greater than that under the slow velocity condition. The dynamic lateral pressure surge is the most obvious in the lower 1/3hn of the silo wall(hn is the height of the silo loading line to the bottom of the silo wall), and the repeated dynamic arch process inside the silo results in different vibration distribution of discharge pressure on the wall, and the overpressure coefficient at this location is higher than the current standard correction coefficient of horizontal lateral pressure Ch. It is feasible to study dynamic lateral pressure by EDEM, and the research results can provide reference for the safety design of silo structures. [ABSTRACT FROM AUTHOR]

In order to improve the ability of remote monitoring and intelligent prevention and control of the operating environment and public safety status of intelligent substation equipment, a substation intelligent auxiliary control system based on three-dimensional model was proposed. According to the equipment selection and layout requirements of substation intelligent auxiliary control system, the database was developed and designed. The 3D model was used to share the 3D design results of substation intelligent auxiliary control system. The 3D design of substation intelligent auxiliary control system was completed through 3D design model verification and infrared dual-authentication 3D modeling, and the 3D modeling algorithm was optimized to obtain the 3D modeling output results. The simulation results show that the system has good output power stability, strong anti-interference ability, high efficiency of closed-loop management and processing of operation and maintenance, which is conducive to improving the remote monitoring and intelligent prevention and control ability of substation equipment. [ABSTRACT FROM AUTHOR]

In order to reveal the risk characteristics of engineering diseases induced by long time series temperature difference in the section from Yiwu to Balikun of Beijing-Urumqi Expressway, the temperature distribution characteristics of pavement structure layer were obtained by analyzing the interannual monitoring data of the ground temperature monitoring section of Balikun, and the quantitative relationship between pavement structure layer temperature and asphalt pavement temperature was retrieved by numerical method. The time evolution law of isothermal diseases of high temperature rutting, temperature fatigue crack and temperature shrinkage crack were also investigated. The results show that the highest temperature of the pavement above 50 ℃ in this section only occurs in June and July, and its occurrence probability is low either, so the road pavement of study area has low high temperature rutting risk simultaneously. In hot season ( from June to September), the proportion of pavement and asphalt upper layer' s daily temperature variation range exceeding 20 ℃ is 51. 9% and 35. 3%, respectively. Therefore, the possibility of temperature fatigue cracks in the asphalt layer of this section is relatively large. Comparably, the semi-rigid base keeps low temperature state in the cold season, and its temperature varies most drastically during February to March. The monthly temperature variation of the semi-rigid layer reaches up to 12. 4 ° C which induces the high temperature shrinkage crack risk in winter. [ABSTRACT FROM AUTHOR]

In order to solve the problem of dynamic change of discrete transfer function model parameters of double-sided permanent magnet synchronous linear motor and low identification accuracy of traditional methods, a system identification method based on stochastic model was proposed. The system characteristics in the motion process were analyzed, and the Box-Jenkins model with random disturbance term was used to identify the parameters of the dynamic system transfer function model. By injecting different frequency inverse M sequence current signals, the system response was fully stimulated, and system identification results under different experimental conditions were compared and analyzed. The prediction error method was selected to define the variance cost function, and the Levenberg Marquardt algorithm was used to iteratively optimize the parameters of the transfer function model. The optimal identification model was obtained by comparing and analyzing the system identification under different sampling frequencies, different injection current amplitudes and different motor speed. The results show that when sampling frequency is 1 000 Hz, injection current amplitude is 2. 0 A and motor speed is 50 mm/ s, the optimal identification simulation output matching degree is 94. 81% and the square difference is 7. 84 × 10- 4. [ABSTRACT FROM AUTHOR]

Longitudinal displacement measurement of track is an important inspection item to ensure the safe operation of railway. In order to solve the problem that the general non-contact vision measurement technology cannot distinguish different track monitoring points, a method for measuring the longitudinal displacement of the track was proposed based on binocular vision. Firstly, a coded marker was designed and fixed at the waist of the track at several monitoring points. Binocular camera was used to take images of the coded marker before and after displacement. In terms of algorithm realization, the spatial coordinates of the center of the template are obtained by means of zero-mean normalized cross-correlation method and coordinate system conversion model to measure the longitudinal displacement of the track. At the same time, a one-dimensional pixel scanning method is proposed to analyze the coding information carried by markers to identify the coding values corresponding to different orbital monitoring points. A reasonable and effective simulation test was carried out in the laboratory. The results show that the average error rate of the proposed method is 1.90% and the coding recognition rate is 100% at the working distance of 2.0 m, which proves the accuracy and feasibility of the proposed method and lays a foundation for the subsequent evaluation of the overall ride comfort of orbit geometry. [ABSTRACT FROM AUTHOR]