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184 results on '"Wang, Changgang"'

1. Critical link identification of power system vulnerability based on modified graph attention network

Author

Wang, Changgang, Wang, Xianwei, Cao, Yu, Li, Yang, Lv, Qi, and Zhang, Yaoxin

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

With the expansion of the power grid and the increase of the proportion of new energy sources, the uncertainty and random factors of the power grid increase, endangering the safe operation of the system. It is particularly important to find out the critical links of vulnerability in the power grid to ensure the reliability of the power grid operation. Aiming at the problem that the identification speed of the traditional critical link of vulnerability identification methods is slow and difficult to meet the actual operation requirements of the power grid, the improved graph attention network (IGAT) based identification method of the critical link is proposed. First, the evaluation index set is established by combining the complex network theory and the actual operation data of power grid. Secondly, IGAT is used to dig out the mapping relationship between various indicators and critical links of vulnerability during the operation of the power grid, establish the identification model of critical links of vulnerability, and optimize the original graph attention network considering the training accuracy and efficiency. Thirdly, the original data set is obtained through simulation, and the identification model is trained, verified and tested. Finally, the model is applied to the improved IEEE 30-node system and the actual power grid, and the results show that the proposed method is feasible, and the accuracy and speed are better than that of traditional methods. It has certain engineering utilization value., Comment: in Chinese language

Published
2024
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7. Development Trend of Downstream Scouring in Flood Discharge Section of Three Gorges Dam

Author

GENG Jun, LI Qi, ZHANG Hailong, WANG Changgang, MEI Xiaolong, and DONG Zongshi

Subjects
flood discharge section, downstream scouring, scouring pit, development trend, Three Gorges Dam, River, lake, and water-supply engineering (General), TC401-506
Abstract

The Three Gorges Dam faces a large outflow, numerous flood discharge facilities, and difficult scheduling and operation during the flood season. The downstream scouring situation of the flood discharge section is complex at different time. Based on the scheduling and operation of flood discharge facilities in different periods since the operation of the project's water storage, the downstream terrain scouring of the flood discharge section in typical years was analyzed. The measured downstream area scouring, as well as the scouring point of the right side of the left guide wall and the left side of the lower longitudinal section of the anti-scouring wall, morphology, and scouring pit elevation in different periods were compared. The development and change trends of downstream scouring of the flood discharge section were studied. The research results indicate that the overall morphology of the downstream scouring pit of the flood discharge section is basically the same in different periods. In the normal operation period, the lowest elevation of the downstream middle scouring pit of the flood discharge section is about 4 m higher than that of the cofferdam in the power generation period, and the scouring situation has generally improved compared with the previous period.

Published
2024

22. An intelligent matching method for the equivalent circuit of electrochemical impedance spectroscopy based on Random Forest.

Author

Chen, Wenbo, Yan, Bingjun, Xu, Aidong, Mu, Xin, Zhou, Xiufang, Jiang, Maowei, Wang, Changgang, Li, Rui, Huang, Jie, and Dong, Junhua

Subjects
RANDOM forest algorithms, MACHINE learning, MILD steel, IMPEDANCE spectroscopy, ELECTROLYTIC corrosion
Abstract

• Automated equivalent circuit model selection in EIS analysis using Random Forest. • Machine learning improves the efficiency and accuracy of selecting equivalent circuit models. • Validation with real-world corrosion data enhances credibility. • Outperforms traditional methods in data processing and accuracy. One of the core works of analyzing Electrochemical Impedance Spectroscopy (EIS) data is to select an appropriate equivalent circuit model to quantify the parameters of the electrochemical reaction process. However, this process often relies on human experience and judgment, which will introduce subjectivity and error. In this paper, an intelligent approach is proposed for matching EIS data to their equivalent circuits based on the Random Forest algorithm. It can automatically select the most suitable equivalent circuit model based on the characteristics and patterns of EIS data. Addressing the typical scenario of metal corrosion, an atmospheric corrosion EIS dataset of low-carbon steel is constructed in this paper, which includes five different corrosion scenarios. This dataset was used to validate and evaluate the proposed method in this paper. The contributions of this paper can be summarized in three aspects: (1) This paper proposes a method for selecting equivalent circuit models for EIS data based on the Random Forest algorithm. (2) Using authentic EIS data collected from metal atmospheric corrosion, the paper establishes a dataset encompassing five categories of metal corrosion scenarios. (3) The superiority of the proposed method is validated through the utilization of the established authentic EIS dataset. The experiment results demonstrate that, in terms of equivalent circuit matching, this method surpasses other machine learning algorithms in both precision and robustness. Furthermore, it shows strong applicability in the analysis of EIS data. [Display omitted] [ABSTRACT FROM AUTHOR]

Published
2025
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24. Expression of B7S1 related with immune infiltration in colorectal cancer

Author

WANG Changgang, LIU Kun, FENG Haoran, JIANG Yimei, SHI Yiqing, CHEN Xianze, SONG Zijia, LI Jun, LI You, CAI Dongli, ZHAO Ren

Subjects
colorectal cancer, b7s1, immune checkpoint, immune microenvironment, tumor-infiltrating lymphocyte, Neoplasms. Tumors. Oncology. Including cancer and carcinogens, RC254-282, Surgery, RD1-811
Abstract

Objective To investigate the expression of B7S1 mRNA which is encoded by VTCN1 and protein levels in colorectal cancer(CRC) with the analysis of relation to clinicopathological characteristics, immune cell infiltration, and prognosis for the evaluation as a immunotherapeutic target in CRC. Methods Both Oncomine and TIMER databases were used to review the expression of VTCN1 in a variety of human solid tumors. The relationship between the expression of VTCN1 and the clinicopathological characteristics of CRC was analyzed using UALCAN and LinkedOmics databases. The expression of VTCN1 which is related with immune infiltration and clinical prognosis was evaluated using Human Protein Atlas database, Kaplan-Meier Plotter and TIMER database. A total of 24 patients with CRC in Ruijin Hospital (North) were collected and the expression of B7S1 protein in both CRC and normal intestinal tissues was detected by immunofluorescence staining. Results It was found in database that VTCN1 was expressed in many human solid tumors. VTCN1 was highly expressed in various subtypes of CRC when compared with that in normal intestinal tissues. The up-regulated VTCN1 was related to tumor stage, lymph node metastasis, distant metastasis, mismatch repair and overall survival rate. VTCN1 was also related to the immune cell infiltration. Immunofluorescence analysis showed that the protein of B7S1 was up-regulated in CRC when compared with that in normal intestinal tissues, and it was expressed in CD45- cells and CD45+ cells. Conclusions As co-inhibitory immune checkpoint molecule, B7S1 may be a potential prognostic factor and might become the target of immunotherapy for CRC.

Published
2021
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26. Retrospective study on laparoscopic surgery combined with intraoperative radiotherapy in treatment of locally advanced rectal cancer

Author

CHEN Xianze, CHENG Xi, ZHAO Shengguang, ZHANG Tao, SHI Yiqing, LIU Kun, WANG Changgang, JIANG Yimei, JI Xiaopin, ZHAO Ren

Subjects
intraoperative radiotherapy, locally advanced rectal cancer, complication, no local recurrence rate, Neoplasms. Tumors. Oncology. Including cancer and carcinogens, RC254-282, Surgery, RD1-811
Abstract

Objective To analyze the efficacy of laparoscopic surgery combined with intraoperative radiotherapy (IORT) using mobile linear accelerator in the treatment of patients with locally advanced rectal cancer (LARC). Methods A retrospective analysis was made on 22 patients with LARC as study group who were treated with laparoscopy combined with IORT in our hospital from January 2012 to January 2016. A total of 44 patients were selected as control group using matched case-control design at 1∶2 based on age, sex, body mass index, mode of operation and tumor TNM stage. The patients in two groups were compared and analyzed. Results Average operative time in study group was longer than that in control group (P=0.024). There was no significant difference in postoperative exhaust time, fluid recovery time, postoperative hospital stay and short-term postoperative complications between study group and control group (P>0.05). The diffe-rences in both no local recurrence rate of 1-year (P=0.742) and 3-year (P=0.533) and overall survival rate of 1-year (P=0.476) and 3-year (P=0.447) were not significant between study group and control group. Conclusions Compared with laparoscopic surgery alone for LARC patients, laparoscopic surgery combined with IORT might increase the operative time. However, there was no significant difference in other operative indexes between two groups. Laparoscopic surgery with IORT could be done safe and feasible, and be comprehensive treatments for LARC patients.

Published
2021
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