A Two-Dimensional Risk Assessment Method for Oil and Gas Pipelines Based on “Accident Probability–Reputation Loss”

Chen Xuefeng,Chen Wentao,Zhang Yifu,Peng Bin,Wang Yuling,Xu Mingwei 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.1

Oil and gas pipeline accidents not only caused personnel casualties, economic losses and environmental pollution but also brought great panic to the public. To provide accurate accident prevention strategies, risk assessment (RA) has been widely used in the oil and gas pipeline industry. It aims to quantify the potential risk due to unexpected eventualities. However, the current RA methods mainly pay attention to the tangible risk (such as the human safety risk, economic risk and environmental risk), and the intangible risk (such as reputation loss risk) is often neglected. This cannot refl ect the real risk for the oil and gas pipeline. To settle existing research limitation, a two-dimensional risk assessment method for oil and gas pipelines based on “accident probability–reputation loss” is proposed. The method mainly involves four steps, namely, risk identifi cation, probability calculation, consequence assessment and risk assessment. The proposed method is used to quantitatively assess a natural gas pipeline in central China. Its results indicate that pipeline risk is unacceptable due to the unacceptability of accident probability and various dimensions of risk. Therefore, this study can enrich and develop the current oil and gas pipeline RA method to refl ect the real risk of oil and gas pipeline accidents.

Millimeter-Wave Channel Modeling Based on A Unified Propagation Graph Theory

Chen, Jiajing,Yin, Xuefeng,Tian, Li,Kim, Myung-Don IEEE 2017 IEEE communications letters Vol.21 No.2

<P>In this letter, a unified propagation graph modeling approach is proposed, which is applicable to predicting multipath radio propagation by considering both specular components (SCs) and diffuse components (DCs). In this approach, the semi-deterministic graph modeling is used to generate multi-bounce DCs, and a single-lobe directive model is applied to reproducing individual single-bounce SCs together with DCs associated. The performance of the proposed approach is assessed by comparing measured channel characteristics with simulation results for 60 GHz millimeter-wave propagation in an office environment.</P>

Identification of DNA methylation and genetic alteration simultaneously from a single blood biopsy

Chen Xiaomin,Liu Jiahui,Li Jun,Xie Yinpeng,Yu Zichen,Shen Lu,Liu Qingfeng,Wu Wei,Zhao Qiang,Lin Haoxiang,Liu Gaotong,Luo Qiuping,Yang Ling,Huang Yi,Zhao Meiru,Yi Xin,Xia Xuefeng 한국유전학회 2023 Genes & Genomics Vol.45 No.5

Background High-throughput sequencing of blood cell-free DNA (cfDNA) techniques offer an opportunity to characterize and monitor cancer rapidly in a non-invasive and real-time manner. Nonetheless, there lacks a tool within therapeutic arsenal to identify multi-omics alterations simultaneously from a single biopsy. In current times, bisulfite-based sequencing detects 5mC and 5hmC at single-base resolution is the golden standard of DNA methylation, while the degradation of DNA and biased sequencing data are the problems of this method. Objective To identify the consistency analysis of methylation and genetic variation with single library, we presented a platform detecting multi-omics data simultaneously from a single blood biopsy using bisulfite-free method of genomic methylation sequencing (GM-seq) mediated by TET enzyme. Methods We detected methylomic and genetic changes simultaneously from a single blood biopsy in NA12878 and randomly chose ten blood biopsies from colorectal cancer or lung cancer patients to validate the ability of GM-seq. Results Similar cytosine methylation level between whole genome bisulfite sequencing (WGBS) and GM-seq were identified in NA12878. Moreover, longer insert size, CpGs coverage and GC distribution were outperformed than WGBS. In addition, the comparison of the single nucleotide polymorphism (SNP), insertion-deletion (Indel) and copy number variation (CNV) in NA12878 or ctDNA from liver cancer between GM-seq and whole genome sequencing (WGS) show a good consistency, indicating that this method is feasible for detecting genetic variation in blood. Conclusion In conclusion, our work demonstrated a method for identification of the methylated modification and genetic variations simultaneously from a single blood biopsy.

Novel Single Switch DC-DC Converter for High Step-Up Conversion Ratio

Xuefeng Hu,Benbao Gao,Yuanyuan Huang,Hao Chen 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3

This paper presents a new structure for a step up dc-dc converter, which has several advantageous features. Firstly, the input dc source and the clamped capacitor are connected in series to transfer energy to the load through dual voltage multiplier cells. Therefore, the proposed converter can produce a very high voltage and a high conversion efficiency. Secondly, a double voltage clamped circuit is introduced to the primary side of the coupled inductor. The energy of the leakage inductance of the coupled inductor is recycled and the inrush current problem of the clamped circuits can be shared equally by two synchronous clamped capacitors. Therefore, the voltage spike of the switch tube is solved and the current stress of the diode is reduced. Thirdly, dual voltage multiplier cells can absorb the leakage inductance energy of the secondary side of the coupled inductor to obtain a higher efficiency. Fourthly, the active switch turns on at almost zero current and the reverse-recovery problem of the diodes is alleviated due to the leakage inductance, which further improves the conversion efficiency. The operating principles and a steady-state analysis of the continuous, discontinuous and boundary conduction modes are discussed in detail. Finally, the validity of this topology is confirmed by experimental results.

LncRNA SNHG20 promotes cell proliferation and invasion by suppressing miR-217 in ovarian cancer

Xing Xuefeng,An Ming,Chen Tonghua 한국유전학회 2021 Genes & Genomics Vol.43 No.9

Background Ovarian cancer is the most common female gynecological malignancy. SNHG20, as a long non-coding RNA, has been proven to be an important regulator in the occurrence and development of various tumors. However, the potential mechanism of SNHG20 in ovarian cancer is unclear. Objective The present study was aimed to investigate the functions and mechanisms of SNHG20 in ovarian cancer. Methods The expression of SNHG20 and miR-217 in ovarian cancer tissues and cell lines was detected by qRT-PCR. CCK-8 assay was used to measure cell proliferation in transfected cells. The transwell assay was used to detect the relative invasion rate of transfected cells. The putative binding sites between SNHG20 and miR-217 were predicted by software LncBase v.2, and the interaction between SNHG20 and miR-217 was confrmed by dual-luciferase reporter assays and RIP assay. The rescue experiments were used to illustrate potential mechanisms. Results SNHG20 was upregulated in ovarian cancer tissues and cell lines. Overexpression of SNHG20 promoted ovarian cancer cell proliferation and invasion. MiR-217 was downregulated in ovarian cancer tissues and cells, and was negatively regulated by SNHG20. Moreover, miR-217 overexpression inhibited ovarian cancer cell proliferation and invasion. Furthermore, miR-217 mimic reversed the inhibitory efect of SNHG20 overexpression on the biological behavior of ovarian cancer cells. Conclusions SNHG20 promoted cell proliferation and invasion by sponging miR-217 in ovarian cancer. These results suggested that SNHG20 and miR-217 might provide new targets for therapeutic application in ovarian cancer.

Reduction of the Retransmission Delay for Heterogeneous Devices in Dynamic Opportunistic Device-to-device Network

( Sixuan Chen ),( Weixia Zou ),( Xuefeng Liu ),( Yang Zhao ),( Zheng Zhou ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.10

The dynamic opportunistic device-to-device (DO-D2D) network will frequently emerge in the fifth generation (5G) wireless communication due to high-density and fast-moving mobile devices. In order to improve the Quality of Experience (QoE) of users with different computing capacity devices in the DO-D2D network, in this paper, we focus on the study of how to reduce the packets retransmission delay and satisfy heterogeneous devices. To select as many devices as possible to transmit simultaneously without interference, the concurrent transmitters-selecting algorithm is firstly put forward. It jointly considers the number of packets successfully received by each device and the device’s connectivity. Then, to satisfy different devices’ demands while primarily ensuring the base-layer packets successfully received by all the devices, the layer-cooperation instantly decodable network coding is presented, which is used to select transmission packets combination for each transmitter. Simulation results illustrate that there is an appreciable retransmission delay gain especially in the poor channel quality network compared to the traditional base-station (BS) retransmission algorithm. In addition, our proposed algorithms perform well to satisfy the different demands of users with heterogeneous devices.

Novel Single Switch DC-DC Converter for High Step-Up Conversion Ratio

Hu, Xuefeng,Gao, Benbao,Huang, Yuanyuan,Chen, Hao The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3

This paper presents a new structure for a step up dc-dc converter, which has several advantageous features. Firstly, the input dc source and the clamped capacitor are connected in series to transfer energy to the load through dual voltage multiplier cells. Therefore, the proposed converter can produce a very high voltage and a high conversion efficiency. Secondly, a double voltage clamped circuit is introduced to the primary side of the coupled inductor. The energy of the leakage inductance of the coupled inductor is recycled and the inrush current problem of the clamped circuits can be shared equally by two synchronous clamped capacitors. Therefore, the voltage spike of the switch tube is solved and the current stress of the diode is reduced. Thirdly, dual voltage multiplier cells can absorb the leakage inductance energy of the secondary side of the coupled inductor to obtain a higher efficiency. Fourthly, the active switch turns on at almost zero current and the reverse-recovery problem of the diodes is alleviated due to the leakage inductance, which further improves the conversion efficiency. The operating principles and a steady-state analysis of the continuous, discontinuous and boundary conduction modes are discussed in detail. Finally, the validity of this topology is confirmed by experimental results.

Crack identification in short shafts using wavelet-based element and neural networks

Xiang, Jiawei,Chen, Xuefeng,Yang, Lianfa Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.33 No.5

The rotating Rayleigh-Timoshenko beam element based on B-spline wavelet on the interval (BSWI) is constructed to discrete short shaft and stiffness disc. The crack is represented by non-dimensional linear spring using linear fracture mechanics theory. The wavelet-based finite element model of rotor system is constructed to solve the first three natural frequencies functions of normalized crack location and depth. The normalized crack location, normalized crack depth and the first three natural frequencies are then employed as the training samples to achieve the neural networks for crack diagnosis. Measured natural frequencies are served as inputs of the trained neural networks and the normalized crack location and depth can be identified. The experimental results of fatigue crack in short shaft is also given.

New decoupled wavelet bases for multiresolution structural analysis

Youming Wang,Xuefeng Chen,Yumin He,Zhengjia He 국제구조공학회 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.35 No.2

One of the intractable problems in multiresolution structural analysis is the decoupling computation between scales, which can be realized by the operator-orthogonal wavelets based on the lifting scheme. The multiresolution finite element space is described and the formulation of multiresolution finite element models for structural problems is discussed. Various operator-orthogonal wavelets are constructed by the lifting scheme according to the operators of multiresolution finite element models. A dynamic multiresolution algorithm using operator-orthogonal wavelets is proposed to solve structural problems. Numerical examples demonstrate that the lifting scheme is a flexible and efficient tool to construct operator-orthogonal wavelets for multiresolution structural analysis with high convergence rate.

Damage detection using the improved Kullback-Leibler divergence

Shaohua Tian,Xuefeng Chen,Zhibo Yang,Zhengjia He,Xingwu Zhang 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.48 No.3

Structural health monitoring is crucial to maintain the structural performance safely. Moreover, the Kullback-Leibler divergence (KLD) is applied usually to asset the similarity between different probability density functions in the pattern recognition. In this study, the KLD is employed to detect the damage. However the asymmetry of the KLD is a shortcoming for the damage detection, to overcoming this shortcoming, two other divergences and one statistic distribution are proposed. Then the damage identification by the KLD and its three descriptions from the symmetric point of view is investigated. In order to improve the reliability and accuracy of the four divergences, the gapped smoothing method (GSM) is adopted. On the basis of the damage index approach, the new damage index (DI) for detect damage more accurately based on the four divergences is developed. In the last, the grey relational coefficient and hypothesis test (GRCHT) is utilized to obtain the more precise damage identification results. Finally, a clear remarkable improvement can be observed. To demonstrate the feasibility and accuracy of the proposed method, examples of an isotropic beam with different damage scenarios are employed so as to check the present approaches numerically. The final results show that the developed approach successfully located the damaged region in all cases effect and accurately.