Unified coordination control strategy for DC solid‑state transformer in DC microgrid

Yanbing Jia,Pei Zhao,Jinjie Tian,Xiangqi Meng,Han Wu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.8

The existing control strategies of DC solid-state transformer (DCSST) are based on DC distribution system, which is mainly concentrated on one side voltage stability control without considering the change of control objectives under different conditions. Thus, they are unsuitable for multiterminal and multisource DC microgrid. The coordinated control strategy of DCSST in multiterminal and multisource DC microgrid is studied in this paper. The DCSST circuit models based on the series–parallel structure of dual active full bridge converter are established, and the basic control modes are analyzed: control low voltage mode and control high voltage mode. Combined with the characteristics of DC bus voltage fluctuation and the operation conditions of DCSST, a unified coordinated control strategy is proposed. Experimental results show that the proposed control strategy can correctly identify the different power states of the two sides of the system, control the power exchange between the two sides of the system, and maintain the stable operation of the whole DC system.

Seismic performance of exterior R/C beam-column joint under varying axial force

Yanbing Hu,Masaki Maeda,Yusuke Suzuki,Kiwoong Jin 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.78 No.5

Previous studies have suggested the maximum experimental story shear force of beam-column joint frame does not reach its theoretical value due to beam-column joint failure when the column-to-beam moment capacity ratio was close to 1.0. It was also pointed out that under a certain amount of axial force, an axial collapse and a sudden decrease of lateral load-carrying capacity may occur at the joint. Although increasing joint transverse reinforcement could improve the lateral load-carrying capacity and axial load-carrying capacity of beam-column joint frame, the conditions considering varying axial force were still not well investigated. For this purpose, 7 full-scale specimens with no-axial force and 14 half-scale specimens with varying axial force are designed and subjected to static loading tests. Comparing the experimental results of the two types of specimens, it has indicated that introducing the varying axial force leads to a reduction of the required joint transverse reinforcement ratio which can avoid the beam-column joint failure. For specimens with varying axial force, to prevent beam-column joint failure and axial collapse, the lower limit of joint transverse reinforcement ratio is acquired when given a column-to-beam moment capacity ratio.

Real-time Detection and Recognition of Landmarks for Mobile Robot in Indoor Scenes

Yanbing Xue,Hua Zhang,Yucui Ju,Jin Wang 보안공학연구지원센터 2013 International Journal of Multimedia and Ubiquitous Vol.8 No.4

Admission Control for Aggregate Flow in Cloud Computing

Yanbing Liu,Yunlong He,Jun Huang 보안공학연구지원센터(IJGDC) 2014 International Journal of Grid and Distributed Comp Vol.7 No.2

Fabrication of Mn-FeOx/CNTs Catalysts for Low-Temperature NO Reduction with NH3

Yanbing Zhang,Zhe Xu,Xie Wang,Xiulian Lu,Yuying Zheng 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.4

Mn-FeOx/carbon nanotubes (CNTs) catalysts were firstly prepared via simple incipient wetness method and used for low-temperature selective catalytic reduction (SCR) of NO with NH3. The structure and surface properties of the catalysts were characterized by N2 sorption, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction by hydrogen (H2-TPR). It was found that Mn-FeOx/CNTs catalyst exhibited excellent low-temperature SCR activity and SO2 resistance. XRD patterns revealed that metal oxides catalysts were possessed of amorphous structure. FESEM and TEM images showed that metal oxides catalysts were successfully supported on CNTs. The XPS results indicated that the obtained catalyst presented high Mn4+/Mn3+ and OS/(OS+OL) ratios. The H2-TPR profiles showed that Mn-FeOx/CNTs catalyst possessed better low-temperature reducibility. Besides, the obtained catalyst exhibited better SO2 resistance.

Design and simulation of 500 MHz single cell superconducting RF cavity for SILF

Sun Yanbing,Ma Wei,Yuan Nan,Ge Yulin,Yang Zhen,Zou Liping,Lu Liang 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.1

Shenzhen Innovation Light source Facility (SILF) is a 3.0 GeV fourth generation diffraction limited synchrotron light source currently under construction in Shenzhen. The SILF storage ring is proposed to use two 500 MHz single cell superconducting radio frequency (SRF) cavities to provide 2.4 MV RF voltage. In this study, we examined the geometric structure of mature CESR superconducting cavities and adopted a beam-pipe-type extraction scheme for high-order modes (HOM). One of the objectives of SRF cavity design and optimization in this study is to reduce Ep/Eacc and Bp/Eacc as much as possible to reduce power loss and ensure stable operation of the cavity. To reduce the risk of beam instability and thermal breakdown, the HOM and Multipacting (MP) are simulated. Moreover, the mechanical properties of the cavity are analyzed, including frequency sensitivity from pressure of liquid helium (LHe), stress, tuning, Lorentz force detuning (LFD), the microphone effect, and buckling. By comprehensive design and optimization of 500 MHz single-cell SRF cavities, a superconducting cavity for SILF storage ring was developed. This paper will detailed present the design and simulation.

Clustering memory-guided anomaly detection model for large-scale screening of esophageal endoscopic images

Wu Yanbing,Zhao Zijian,Pang Xuejiao,Liu Jin 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.4

A deep learning screening model of esophageal endoscopic images can reduce the burden on endoscopists. However, most deep learning methods require many labeled data with balanced categories, and their ability to deal with new diseases not appearing in the training set is limited. This study elaborated a semi-supervised anomaly detection model for the initial screening of esophageal endoscopic images, requiring a single class of samples as a training set. The reconstruction-based method was used for anomaly detection. The model’s framework was a variational auto-encoder, with two memory modules added in latent space to restrain its generalization ability. In the memory module, a clustering operation was introduced to provide a better distribution of memory vectors, promoting their compactness with encoded features and separation from each other. A detailed description and theoretical substantiation of the proposed model were presented. A dataset containing 7989 esophageal endoscopic images labeled by experienced endoscopists was used for numerical experiments. The proposed model results were compared with those of other auto-encoder-based anomaly detection methods, outperforming them and achieving an area under the curve of 0.8212. The ablation study was also conducted to validate the effectiveness of each model’s part, and new data were successfully incorporated to assess the model feasibility and applicability range.

Effects of Ensiling Fermentation and Aerobic Deterioration on the Bacterial Community in Italian Ryegrass, Guinea Grass, and Whole-crop Maize Silages Stored at High Moisture Content

Li, Yanbing,Nishino, Naoki Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.9

The effects of storage period and aerobic deterioration on the bacterial community were examined in Italian ryegrass (IR), guinea grass (GG), and whole-crop maize (WM) silages. Direct-cut forages were stored in a laboratory silo for 3, 7, 14, 28, 56, and 120 d without any additives; live counts, content of fermentation products, and characteristics of the bacterial community were determined. 2,3-Butanediol, acetic acid, and lactic acid were the dominant fermentation products in the IR, GG, and WM silages, respectively. The acetic acid content increased as a result of prolonged ensiling, regardless of the type of silage crop, and the changes were distinctively visible from the beginning of GG ensiling. Pantoea agglomerans, Rahnella aquatilis, and Enterobacter sp. were the major bacteria in the IR silage, indicating that alcoholic fermentation may be due to the activity of enterobacteria. Staphylococcus sciuri and Bacillus pumilus were detected when IR silage was spoiled, whereas between aerobically stable and unstable silages, no differences were seen in the bacterial community at silo opening. Lactococcus lactis was a representative bacterium, although acetic acid was the major fermentation product in the GG silage. Lactobacillus plantarum, Lactobacillus brevis, and Morganella morganii were suggested to be associated with the increase in acetic acid due to prolonged storage. Enterobacter cloacae appeared when the GG silage was spoiled. In the WM silage, no distinctive changes due to prolonged ensiling were seen in the bacterial community. Throughout the ensiling, Weissella paramesenteroides, Weissella confusa, and Klebsiella pneumoniae were present in addition to L. plantarum, L. brevis, and L. lactis. Upon deterioration, Acetobacter pasteurianus, Klebsiella variicola, Enterobacter hormaechei, and Bacillus gibsonii were detected. These results demonstrate the diverse bacterial community that evolves during ensiling and aerobic spoilage of IR, GG, and WM silages.

Energy-Efficiency and Transmission Strategy Selection in Cooperative Wireless Sensor Networks

Zhang, Yanbing,Dai, Huaiyu The Korea Institute of Information and Commucation 2007 Journal of communications and networks Vol.9 No.4

Energy efficiency is one of the most critical concerns for wireless sensor networks. By allowing sensor nodes in close proximity to cooperate in transmission to form a virtual multiple-input multiple-output(MIMO) system, recent progress in wireless MIMO communications can be exploited to boost the system throughput, or equivalently reduce the energy consumption for the same throughput and BER target. However, these cooperative transmission strategies may incur additional energy cost and system overhead. In this paper, assuming that data collectors are equipped with antenna arrays and superior processing capability, energy efficiency of relevant traditional and cooperative transmission strategies: Single-input-multiple-output(SIMO), space-time block coding(STBC), and spatial multiplexing(SM) are studied. Analysis in the wideband regime reveals that, while receive diversity introduces significant improvement in both energy efficiency and spectral efficiency, further improvement due to the transmit diversity of STBC is limited, as opposed to the superiority of the SM scheme especially for non-trivial spectral efficiency. These observations are further confirmed in our analysis of more realistic systems with limited bandwidth, finite constellation sizes, and a target error rate. Based on this analysis, general guidelines are presented for optimal transmission strategy selection in system level and link level, aiming at minimum energy consumption while meeting different requirements. The proposed selection rules, especially those based on system-level metrics, are easy to implement for sensor applications. The framework provided here may also be readily extended to other scenarios or applications.

A Study on the Effectiveness of Concert Band in Music Therapy on Social Anxiety Intervention for Chinese Medical College Students

주언빙(Zhou, Yanbing)(周彥,冰,),고흥(Kou, Heung)(高興) 학습자중심교과교육학회 2022 학습자중심교과교육연구 Vol.22 No.3

목적 중국 의대생을 대상으로 대학생들의 정신건강과 사회적 불안 현황을 조사했다. 이번 연구는 의대생들의 정신건강과 사회적 불안에 대한 음악치료 도구로서의 콘서트밴드의 활용에 대한 연구 결과를 바탕으로 대학생들의 사회적 불안 개선에 도움을 주기 위해 실시했다. 방법 이 연구는 양적 연구 형태를 채택하고, SPSS 25.0 통계 분석 소프트웨어를 사용하여 통계를 수집하고, 의대 학생 118명을 연구 대상으로 삼고, 신뢰도와 학교 학위가 좋은 설문지를 사용하여 실증 조사를 실시했다. 결과 증상 검사 목록-90(SCL-90, Symptom Checklist-90)과 SADS(Social Avoidance and Distress Scale)에서는 전반적으로 총 평균 점수와 각 하위 차원 간에 유의한 차이가 여러 개 있었다. SCL-90 척도의 실험 그룹과 대조군 사이에는 사전 테스트 및 사후 테스트 조사를 사용한 비교 그룹에서 몇 가지 차원의 통계적 차이가 없었다. 그러나 테스트 후 체질화 점수(M=15.22, SD=6.23)는 테스트 전 점수(M=24.11, SD=7.16)보다 낮았다. 실험 후 실험군은 주관적 괴로움 및 행동 회피(실증적 괴로움: M=5.05, SD=2.36, 행동 회피: M=6.26, SD=1.77, 총점: M=11.30, SD=3.36)에서 시험 후 대조군(실증적 괴로움: M=6.92, SD=2)보다 낮은 점수를 받았다. M= 7.32, SD= 2.25; 총점: M=14.22, SD=3.60). 곡선모형은 불안요인, 주관적 괴로움, 행동 기피가 대학생들의 정신건강과 사회적 불안에 대한 중요한 예측 변수(Y=5.258X+62.666, Y=-.148X2+11.2923X+10.052; Y=8.470X+108.460, Y=-.147X2+10.112X+109.197; Y=9.028X+103.111, Y=-.074X2+9.101X+105.059)로 나타났다. 결론 대학생들의 전반적인 정신건강은 정상적이었으며, 종합정신건강에 대한 시험 전 평가에서 대조군과 실험군의 큰 차이는 없었으며, 실험군의 체질과 사회적 불안은 사후 검사에서 크게 개선되었다. Objectives Taking Chinese medical college students as the target, this paper explores the current situation of college students’ mental health and social anxiety, studies the influence of Concert Band as a music therapy on medical college students mental health and social anxiety, and discusses that Concert Band as a music therapy can reduce college students social anxiety according to the research results. Methods This research adopts the form of quantitative research, uses SPSS 25.0 statistical analysis software to collect statistics, takes 118 medical university students as the research objects, and uses questionnaires with good reliability and school degree to conduct an empirical investigation. Results In the SCL-90(Symptom Checklist-90) and the SADS(Social Avoidance and Distress Scale), overall, there were multiple significant differences between the total mean scores and each sub-dimension. There were no statistical differences between the experimental and control groups on the SCL-90 scale in several dimensions in the comparative group with pretest and post-test surveys. Still, the post-test somatization score (M=15.22, SD=6.23) was lower than the pretest score (M=24.11, SD=7.16). In the post-test, the experimental group scored lower in subjective distress, and behavioral avoidance (subjective distress: M=5.05, SD=2.36; behavioral avoidance: M=6.26, SD=1.77; total score: M=11.30, SD=3.36) than the posttest control group (subjective distress: M=6.90, SD=2.92; behavioral avoidance: M= 7.32, SD=2.25; total score: M=14.22, SD=3.60). The curve models indicated that anxiety factor, subjective distress, and behavioral avoidance were significant predictors of mental health and social anxiety among college students(Y=5.258X+62.666, Y=-.148X2+11.2923X+10.052; Y=8.470X+108.460, Y=-.147X2+10.112X+109.197; Y=9.028X+103.111, Y=-.074X2+9.101X+105.059). Conclusions The overall quality of dance classroom teaching in colleges and universities is above the middle level. The classroom teaching effect factor performed well, the classroom teaching implementation was the second, and the overall level of the after-class teaching preparation factor was relatively low.