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Object tracking in satellite videos poses a significant challenge for existing trackers due to the typical involvement of small objects, multiple similar disruptors, and occlusions. To improve the performance of remote sensing tracking, a novel motion-aware correlation filter (MACF) algorithm is developed in this study. The proposed approach provides the following improvements: 1) a motion estimation module based on the historical trajectory of the target is embedded into an enhanced spatial–temporal regularized correlation filter (CF)-based tracking framework, to suppress distractions caused by similar objects (SOs); and 2) a failure correction module is employed to deal with the occlusion problem, thereby further enhancing the tracking robustness. Extensive experiments are conducted on the publicly available VISO and SatSOT datasets, with the experimental results demonstrating that the proposed MACF algorithm achieves superior accuracy in comparison to state-of-the-art trackers. Particularly, the present approach has offered the first-place solution for the single object tracking task given in the ICPR 2022 challenge, on moving object detection and tracking in satellite videos (SatVideoDT).

This paper presents a study of closely spaced double tunnels in Taizhou, China. One is Xiabei Mountain No. 2 four-line super-span high-speed railway tunnel (HRT), and the other is Xiabei Mountain double-line large-span subway tunnel (ST). The excavation spans of HRT and ST are 26.3 and 14 m, respectively. The two tunnels are located at different levels, and their separating distance is 17.2 m. Due to the short construction period, the HRT excavation was completed earlier than ST. The structural design of the HRT, taking account of the disturbance by the ST construction, was analyzed by a numerical simulation. It was found that the “yielding principle” design was more feasible than the “resistance principle” design when considering the safety and durability of the HRT secondary lining. The mechanical responses of the HRT during ST construction were comprehensively monitored and analyzed, including the vault settlement, horizontal convergence, surrounding rock pressure, and the internal stress in shotcrete and steel arch. Results show that the longitudinal influence range of the ST construction on the HRT was approximately 0.6–1.1 times the ST outer diameter; the disturbance was mainly generated in the ST upper bench excavation; and the final axial force of the HRT shotcrete was approximately 9–16 times that of the steel arch, which indicated that the shotcrete was the main bearing structure. The safety status of the HRT was assessed based on the monitoring data, and the minimum safety factors of the HRT shotcrete and steel arch were 1.61 and 1.89, respectively. Parametric studies were performed to show how the lining stress of HRT was affected by the relative angle, pillar width, ST excavation method and excavation footage. Finally, the design and construction optimization were proposed according to the monitoring data and parameter analysis results. This study might provide practical reference for similar projects.

Small flux ropes (SFRs) have been studied for decades, but their source regions and formation mechanisms are still under debate. In this study, we focus on the formation mechanism of the twisted structures of SFRs. Current research on magnetic clouds suggests five‐type distributions of the time structure of iron average charge states (Q), which imply different formation mechanisms of twisted structures. We use a similar method to identify the Qtypes of 25 SFRs. However, only four of these five types of distributions are found among these SFRs. Because different origins of SFRs are characteristically affecting the formation of Qtypes, the possible source regions of these SFRs are distinguished. With additional compositional parameters, SFRs are reconfirmed to originate from two types of source regions: the solar corona and the interplanetary medium. Based on these results, our analysis indicates that the twisted structures of SFRs originating from the solar corona may be formed predominately during eruptions. SFRs originating from interplanetary space are related to complex magnetic reconnection processes, which may result in intricate Qdistributions due to the reconstruction of magnetic field topology. The small flux ropes have been categorized into four types considering the characteristics of the iron charge statesSmall flux ropes may have their twisted structures formed predominately during their eruption processesSmall flux ropes are reconfirmed to have two source regions