Data hiding technology plays an important role in many areas related to people's life, such as military and medical images. However, it is difficult to obtain high embedding capacity in compressed images, and it may cause obvious image distortion. Also, the target image's file size should be controlled, as a significant increase in file size may cause the interceptor's attention. In the field of data hiding, many people have proposed feasible solutions. However, considering the visual quality and embedding rate of images, more improvements are needed. In this paper, the histogram shift is used to realize data hiding of JPEG images. The secret message bits are embedded in the high-frequency coefficients to ensure a higher embedding rate, and the high-frequency coefficients are obtained by histogram distribution. The optimal threshold is used to select a discrete cosine transform (DCT) coefficient sub-block that is suitable to embed the secret message and further improve the visual quality of the target image. The experiments show that our solution is significantly better than the most advanced technology in terms of embedding rate and visual quality.INDEX TERMS Data hiding, JPEG images, DCT coefficient, histogram shift.

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The train operation problem at the railway station is one of the basic scheduling problems for railway companies, and the decomposition and combination of trains in station platform tracks is an important trend in the railway operation, which further increase the complexity of train routing problem in the high-speed railway station. A reasonable train routing plan is critical for ensuring the safety and efficiency of train operations within the stations. Considering the combination and decomposition process of trains at the station, a multi-objective model is constructed, which determines the receiving routes and departure routes of trains at the railway station with the limited infrastructure capacity, given the station yard layouts, train diagram and relevant technical operation time of the station. A solution framework based on the “constraint method” is designed, and software Gurobi is used to solve the problem. The Pareto optimal solution set is obtained. The results show that when making 1.9% concessions to the minimum route cost, the occupancy balance of platform tracks can be improved by 66.2%, which is taken as the comprehensive application scheme. Compared with the feasible scheme, the comprehensive operation scheme reduces the route cost by 1.9% and improves the occupation balance of platform tracks by 15.4%.