Camera-aware Proxies for Unsupervised Person Re-Identification

This paper tackles the purely unsupervised person re-identification (Re-ID) problem that requires no annotations. Some previous methods adopt clustering techniques to generate pseudo labels and use the produced labels to train Re-ID models progressively. These methods are relatively simple but effective. However, most clustering-based methods take each cluster as a pseudo identity class, neglecting the large intra-ID variance caused mainly by the change of camera views. To address this issue, we propose to split each single cluster into multiple proxies and each proxy represents the instances coming from the same camera. These camera-aware proxies enable us to deal with large intra-ID variance and generate more reliable pseudo labels for learning. Based on the camera-aware proxies, we design both intra- and inter-camera contrastive learning components for our Re-ID model to effectively learn the ID discrimination ability within and across cameras. Meanwhile, a proxy-balanced sampling strategy is also designed, which facilitates our learning further. Extensive experiments on three large-scale Re-ID datasets show that our proposed approach outperforms most unsupervised methods by a significant margin. Especially, on the challenging MSMT17 dataset, we gain $14.3\%$ Rank-1 and $10.2\%$ mAP improvements when compared to the second place. Code is available at: \texttt{https://github.com/Terminator8758/CAP-master}.Comment: Accepted to AAAI 2021. Code is available at: https://github.com/Terminator8758/CAP-maste

The Calculation Method of Safety Degree and Its Application in Coal Mine Enterprises

In order to evaluate the situation of safety production of coal mine enterprises effectively, quantitative analysis is necessary and very important. Safety degree of coal mine enterprises based on the concept of safety degree is defined and the method of calculating quantitatively the safety degree is put forward. The validity of this method is verified by empirical research in view of micro‐ and macroanalyses. In view of micro analysis the safety degree is derived with the calculation method based on information of one coal mine. The safety degree of this coal mine went through rapid increase period, stable period, and slow increase period. Macroresearch results show that the situation of safety production of coal mine enterprises in China has significantly been improving and the level of safety degree also has been increasing year by year since 1979, the year when the policy of reform and opening began. The reasons are the advancement of technology, strengthening of safety management and education, increasing of safety investment, and perfection of policies, laws, and regulations. These achievements can provide quantitative method for assessing the status of coal mines

Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite

As China's first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band (1-250 keV) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 MeV. It was designed to perform pointing, scanning and gamma-ray burst (GRB) observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed. Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.Comment: 29 pages, 40 figures, 6 tables, to appear in Sci. China-Phys. Mech. Astron. arXiv admin note: text overlap with arXiv:1910.0443

Value of traditional noninvasive fibrosis models in diagnosis of significant liver fibrosis in patients with chronic hepatitis B and metabolic associated fatty liver disease

Objective　To investigate the value of traditional noninvasive fibrosis models in the diagnosis of significant liver fibrosis inpatients with chronic hepatitis B（CHB）and metabolic associated fatty liver disease（MAFLD）. Methods　A total of 499 patients who underwent liver pathological examination in Department of Hepatology，Guangdong Provincial Hospital of Traditional Chinese Medicine，from September 2014 to December 2020 and met the diagnostic criteria for CHB and MAFLD were enrolled in this study.The Scheuer scoring system was used to evaluate the degree of liver fibrosis. The Mann－Whitney U test was used for comparison of normally distributed continuous data between groups. A Spearman correlation analysis was used to investigate the correlation of each noninvasive diagnostic method with the degree of liver fibrosis；the receiver operating characteristic（ROC）curve was plotted to investigate the value of FibroScan，gamma－glutamyl transpeptidase－to－platelet ratio（GPR）， aspartate aminotransferase－to-platelet ratio index（APRI），fibrosis－4（FIB－4），and liver stiffness measurement－to－platelet ratio index（LPRI）in the diagnosis of CHB with MAFLD；a binary Logistic regression analysis was used to construct a combined model，and the area under the ROC curve（AUC）was compared between the combined model and the five indicators used alone. The DeLong method was used for comparison ofAUC between any two noninvasive diagnostic methods. Results　There were 198 patients in the group with no or mild liver fibrosis（S0－S1）and 301 patients in the group with significant liver fibrosis（S≥2）. The S≥2 group had higher clinical indicators than the S0－S1 group，with significant differences between the two groups in alanine aminotransferase，aspartate aminotransferase， gamma－glutamyl transpeptidase，total bilirubin，GPR，FIB－4，APRI，LPRI，and liver stiffness measurement（LSM）（ all P< 0.05）. The Spearman correlation analysis showed that GPR，FIB－4，APRI，LSM，and LPRI were positively correlated with the stage of liver fibrosis（r = 0.393，0.414，0.449，0.553，and 0.580，all P<0.001）. The ROC curve analysis showed that GPR，FIB-4，APRI，LSM，and LPRI used alone had an AUC of 0.704，0.715，0.740，0.787，and 0.802，respectively，in the diagnosis of significant liver fibrosis. The binary Logistic regression analysis was used to construct a combined LGAF model of GPR，FIB－4， APRI，and LSM，which had an AUC of 0.814 in the diagnosis of significant liver fibrosis. LGAF was compared with GPR，FIB－4， APRI，LSM，and LPRI，respectively，in terms of AUC，and the results showed that there was a significant difference between LGAF and all five indicators except LPRI（Z=5.184，4.884，4.117，and 2.120，all P<0.05）. Conclusion　The five data models of FibroScan，GPR，APRI，FIB－4，and LPRI have a similar value in the diagnosis of significant liver fibrosis in CHB with MAFLDcompared with the combined LGAF model，which provides reference and guidance for the application of noninvasive assessment of liver fibrosis in clinical practice

Research and Analysis on the Supporting Structure of the Second Lining of the Tunnel in the Phyllite Stratum

The reasonable construction of the secondary lining structure of the tunnel is an important link to ensure the stability of the surrounding rock of the tunnel. Taking a phyllite stratum tunnel project in Jiangxi as the background, the Flac3D finite difference software was used to numerically simulate and analyze the supporting structure of the secondary lining. The impact of support timing on surrounding rock stress. The calculation results show that with the progress of the construction step, the main period of the displacement of the vault is after the excavation of the upper section of the tunnel before the upper section support; The plastic zone of the surrounding rock changes obviously, especially above the tunnel, and finally the plastic zone develops to the ground; the stress of the surrounding rock shows a decreasing trend with the increase of the time of the secondary lining. The research results can provide certain guiding significance for the construction of the second lining of the tunnel under similar geological conditions

The Development of Microstructure of Coal by Microwave Irradiation Stimulation

Microwave fracturing has been proposed as an alternative approach to stimulate coalbed methane reservoirs as it is environmentally friendly, widely applicable and economical. Different microwave parameters (microwave power and treatment time) and saturation conditions of coal have great effect on the microwave heating effect, which further results in different microwave fracturing effects. In this study, repeated nuclear magnetic resonance experiments and quantitative analysis were performed to investigate the effects of microwave power, irradiation time and saturation condition on microstructure development of coal. Three indicators including macropore and fissure proportion variation (MFPV), variation rate of water porosity (VRWP) and moisture loss were proposed to evaluate microwave\u27s effect on pore structure. It was found that the pore size, water porosity and moisture loss increase with rising microwave power and irradiation time. Microwave\u27s effect on coal sample with saturations ranged from 0% to 100% was first studied in this paper. The results show that microwave irradiation has great effect on pore structure of coal samples when water saturation is less than 25% and becomes insignificant when the water saturation is larger than 50%. Surface topography measurements and SEM experiments were also performed before and after microwave treatment to observe the microstructure development. New fissures and cracks were observed on the surface of samples and the surface become smooth with less accumulated particles after microwave irradiation