A wireless sensor node is typically battery operated and energy constrained. Therefore, it is apparent that optimal energy management is one of the most important challenges in WSN development. However, energy management requires in-depth knowledge and detailed insight concerning specific scenarios. After Carrying out a large number of experiments in precision agriculture, we find that it is the sensors that have never been concerned consuming the most energy of the node. In order to conserve energy and prolong the lifetime of WSN, we design and carry out a dynamic energy management strategy for sensors. The basic idea is to shut down all sensors' power when not needed and wake them up when necessary. Valuable conclusions are extracted and analyzed.

The load of large-size vehicles has not been clearly defined in the existing bridge design codes in our country. When large-size vehicles cross the bridge, the bridge has certain safe-ty hazards. At present, there are not many evaluation methods for the driving safety of large-size transportation bridge structures. In order to scientifically evaluate the traffic safety of the large-size transportation bridge structure, this paper considers the factors of bridge, traffic and environment, and establishes the evaluation index system for the operation safety of the large-size transportation bridge structure, using the comprehensive weighting method of the G1-entropy weight method. Calculating the weight and combining the fuzzy comprehensive evaluation method to evaluate the traffic of the large-scale transportation bridge in Huanglong County, Shaanxi Province, the results show that the traffic safety level of the bridge is level II, which has good safety.

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In order to reasonably match the horizontal and vertical sections of high-speed railway lines, the vehicle-line spatial coupling model of the vertical-circular overlapping line is established, based on the multi-body dynamics simulation software SIMPACK,. The dynamic indexes of train passing through vertical-circular overlapping lines are calculated when the radii of different plane curves match the corresponding superelevation value. The results show that: on the vertical-circular overlapping line, it is suggested that the maximum plane curve radius is 9000m.The existence of the convex vertical-circular overlapping line worsens the safety of train operation and passenger comfort. The existence of the concave vertical-circular overlapping line is the opposite, but it increases rail wear and the workload of maintenance. The vertical-circular overlapping line has the most obvious influence on the vertical acceleration and the vertical Sperling index of the body. The vertical acceleration of the body is superimposed at the plane gentle circle point and the starting point of the vertical curve, which has a great impact on the stability of the train operation.

With the continuous improvement of China's railway construction level, the requirements for the quality of train operation are also improved. For the mixed passenger and freight railway, it is necessary to transit from the simple design concept of safety to the design concept of the unity of comfort and safety. Therefore, modern numerical calculation method or simulation software method is used to replace the traditional quasi-static calculation method, and SIMPACK, ABAQUS and other related software are mainly used to analyze the operation quality and track structure dynamics of the line design scheme. The derailment coefficient, vertical acceleration and other evaluation indexes are used to evaluate the safety and comfort of the line, and the dynamic analysis of the track structure is carried out based on the vertical force. The research shows that under the condition of this line, when the passenger and freight train run at the designed speed per hour in the curve section, they can meet the specification requirements of various indexes, and there is still room for increasing speed, and the stress and strain value of the track structure can meet the specification requirements.