With the launch of the Sentinel-1 satellites, it becomes easy to obtain long time-series dual-pol (i.e., VV and VH channels) SAR images over most areas of the world. By combining the information from both VV and VH channels, the polarimetric persistent scatterer interferometry (PolPSI) techniques is supposed to achieve better ground deformation monitoring results than conventional PSI techniques (using only VV channel) with Sentinel-1 data. According to the quality metric used for polarimetric optimizations, the most commonly used PolPSI techniques can be categorized into three main categories. They are PolPSI-ADI (amplitude dispersion index as the phase quality metric), PolPSI-COH (coherence as the phase quality metric), and PolPSI-AOS (taking adaptive optimization strategies). Different categories of PolPSI techniques are suitable for different study areas and with different performances. However, the study that simultaneously applies all the three types of PolPSI techniques on Sentinel-1 PolSAR images is rare. Moreover, there has been little discussion about different characteristics of the three types of PolPSI techniques and how to use them with Sentinel-1 data. To this end, in this study, three data sets in China have been used to evaluate the three types of PolPSI techniques’ performances. Based on results obtained, the different characteristics of PolPSI techniques have been discussed. The results show that all three PolPSI techniques can improve the phase quality of interferograms. Thus, more qualified pixels can be used for ground deformation estimation by PolPSI methods with respect to the PSI technique. Specifically, this pixel density improvement is 50%, 12%, and 348% for the PolPSI-ADI, PolPSI-COH, and POlPSI-AOS, respectively. PolPSI-ADI is the most efficient method, and it is the first choice for the area with abundant deterministic scatterers (e.g., urban areas). Benefitting from its adaptive optimization strategy, PolPSI-AOS has the best performances at the price of highest computation cost, which is suitable for rural area applications. On the other hand, limited by the medium resolution of Sentinel-1 PolSAR images, PolPSI-COH’s improvement with respect to conventional PSI is relatively insignificant.
The course of outdoor sports is one of the important curriculums of physical education department and specialty, which has strong practical characteristics. Taking the outdoor sports talents training of physical education specialty of China University of Geosciences (Wuhan) as the research object, this paper uses the methods of documentation, questionnaire survey, field investigation and case analysis, and combines the content and characteristics of outdoor sports practice teaching courses in colleges and universities of Hubei Province, explores the construction idea of "base group" of outdoor sports practice teaching. Starting from the training goal of coordinated development of knowledge, technique and skills of sports professionals, the "base group" of outdoor sports practice teaching is constructed according to different regions, projects, times and groups of people. The paper discusses the innovation construction system of "base group" composed of five subsystems including target, curriculum, management, guarantee and the evaluation of practice teaching. The "five-in-one" practicing base group evaluation system of outdoor sports is probed, aiming at the cultivating of outdoor sports professionals who satisfy the social requirements, meet the characteristics of students' development, and possess the theoretical skills and practical abilities.
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