Comparison of RV, ARV and WRV Based on MEM

Cao Gang,Guo Mingyuan,Zou Wenjun 보안공학연구지원센터 2012 International Journal of Control and Automation Vol.5 No.4

그래프 학습을 통한 시공간 Attention Network 기반 POI 추천

조강 ( Cao Gang ),조인휘 ( Inwhee Joe ) 한국정보처리학회 2022 한국정보처리학회 학술대회논문집 Vol.29 No.2

POI (Point-of-Interest) 추천은 다양한 위치 기반 서비스에서 중요한 역할을 있다. 기존 연구에서는 사용자의 모바일 선호도를 모델링하기 위해 과거의 체크인의 공간-시간적 관계를 추출한다. 그러나 사용자 궤적에 숨겨진 개인 방문 경향을 반영할 수 있는 structured feature 는 잘 활용되지 않는다. 이 논문에서는 궤적 그래프를 결합한 시공간 인식 attention 네트워크를 제안한다. 개인의 선호도가 시간이 지남에 따라 변할 수 있다는 점을 고려하면 Dynamic GCN (Graph Convolution Network) 모듈은 POI 들의 공간적 상관관계를 동적으로 집계할 수 있다. LBSN (Location-Based Social Networks) 데이터 세트에서 검증된 새 모델은 기존 모델보다 약 9.0% 성능이 뛰어나다.

Neural Network Sliding Mode Control Based on On-Line Identification for Electric Vehicle with Ultracapacitor-Battery Hybrid Power

Jian-Bo Cao,Bing-Gang Cao 제어·로봇·시스템학회 2009 International Journal of Control, Automation, and Vol.7 No.3

In order to deal with three major problems of electric vehicle (EV): the short driving range, the short life of batteries, and the poor ability of start-up, a hybrid power system was designed and applied to the EV. It was composed of an ultracapacitor with high-specific power and long life, four lead-acid batteries, and a bi-directional DC/DC converter. To improve the stability and reliability of the hybrid-power EV, based on establishing the mathematical models of driving and regenerative-braking processes, a novel neural network sliding mode controller (NNSMC) was researched and designed for the EV. The controller comprises a back propagation neural network (BPNN), a radial basis function neural network (RBFNN), and a sliding mode controller (SMC). The BPNN is used to adaptively ad-just the switching gain of the SMC on-line so as to avoid the whippings. The RBFNN is used to per-form system identification and parameter prediction. The experimental results show that the NNSMC is superior to PID controller at response speed, steady-state tracking error and resisting perturbation whenever driving or braking. Additionally, the hybrid-power EV with NNSMC can improve the ability of start-up, recover more energy, lengthen the life of batteries, and increase the driving range than the EV using batteries as its single power source by about 40%, and than the hybrid-power EV with PID controller by about 4%.

Design of Fractional Order Controller Based on Particle Swarm Optimization

Jun-Yi Cao,Bing-Gang Cao 대한전기학회 2006 International Journal of Control, Automation, and Vol.4 No.6

An intelligent optimization method for designing Fractional Order PID (FOPID) controllers based on Particle Swarm Optimization (PSO) is presented in this paper. Fractional calculus can provide novel and higher performance extension for FOPID controllers. However, the difficulties of designing FOPlD controllers increase, because FOPID controllers append derivative order and integral order in comparison with traditional PID controllers. To design the parameters of FOPID controllers, the enhanced PSO algorithms is adopted, which guarantee the particle position inside the defined search spaces with momentum factor. The optimization performance target is the weighted combination of ITAE and control input. The numerical realization of FOPlD controllers uses the methods of Tustin operator and continued fraction expansion. Experimental results show the proposed design method can design effectively the parameters of FOPID controllers.

Mapping QTLs for Root Morphological Traits in Brassica rapa Based on AFLP and RAPD Markers

Gang Lu,Jiashu Cao,Wanzhi Ye,Xun Xiang,Hang Chen 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Effects of dietary spermine supplementation on cell cycle, apoptosis, and amino acid transporters of the thymus and spleen in piglets

Cao, Wei,Wu, Xianjian,Jia, Gang,Zhao, Hua,Chen, Xiaoling,Wu, Caimei,Cai, Jingyi,Wang, Jing,Liu, Guangmang Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.8

Objective: This study investigated whether spermine supplementation could regulate cell cycle, apoptosis, and amino acid transporter-related genes expression in the thymus and spleen of early weaned piglets. Methods: Eighty female piglets were randomly distributed to receive adequate nutrients supplemented with spermine (0.4 mmol/kg body weight/24 h) or to be provided with restricted nourishment supplemented with normal saline for 7 h or 3, 6, or 9 d in pairs. Results: Regardless of administration time, spermine supplementation significantly up-regulated cyclin A2 gene expression but down-regulated p21 and cyclin D3 mRNA levels in the thymus and spleen and reduced cyclin E2 gene expression in the thymus of piglets (p<0.05). Irrespective of the treatment period, the reduced Bax and caspase-3 gene expressions and improved Bcl-2 mRNA level were observed in the thymus and spleen of spermine-administrated piglets (p<0.05). Regardless of supplementation time, spermine intake significantly enhanced the expressions of amino acid transporter-related genes (SLC1A1, SLC1A5, SLC7A1, SLC7A7, and SLC15A1) in both thymus and spleen, as well as SLC7A9 in the spleen of piglets (p<0.05). In addition, extended spermine administration also markedly promoted cell proliferation, depressed apoptosis and modulated amino acid transport (p<0.05), and such effects were the greatest during prolonged spermine supplementation (6 d) compared to the other time periods (p<0.05). Conclusion: Spermine supplementation may regulate cell cycle during the G1/S phase, suppress apoptosis and modulate amino acid transport. A period of 6 d of spermine supplementation is required to produce the optimal effects on nutritional implications.

Influence of hexapod robot foot shape on sinking considering multibody dynamics

Gang He,Zhaoyuan Cao,Qian Li,Denglin Zhu,Ji Aimin 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.9

Hexapod robots have attracted attention for their excellent terrain adaptabilities. When a robot walks on soft soil, dynamic subsidence and slippage greatly reduce its walking performance. The influence of foot’s shape is usually ignored or simply studied without considering the multibody dynamics of the robot. This study is focused on the influence of the foot shape on the walking performance of a robot by coupling the sinkage with multibody dynamics. A composite contact model based on the Bekker, spring-damping, and Janosi– Hanamoto models was used to model the interaction of the robot and soft soil. Non-uniform rational B-spline (NURBS) surface and mesh were used to describe the geometries of foot and soft soil, respectively. The influences of three foot shapes on the sinkage and walking stability of the robot were analyzed by comparsion. The improved X-shaped foot reduced the robot’s sinkage and improved its walking stability.

Structural analysis and optimization of large cooling tower subjected to wind loads based on the iteration of pressure

Gang Li,Wen-bin Cao 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.46 No.5

The wind load is always the dominant load of cooling tower due to its large size, complex geometry and thin-wall structure. At present, when computing the wind-induced response of the large-scale cooling tower, the wind pressure distribution is obtained based on code regulations, wind tunnel test or computational fluid dynamic (CFD) analysis, and then is imposed on the tower structure. However, such method fails to consider the change of the wind load with the deformation of cooling tower, which may result in error of the wind load. In this paper, the analysis of the large cooling tower based on the iterative method for wind pressure is studied, in which the advantages of CFD and finite element method (FEM) are combined in order to improve the accuracy. The comparative study of the results obtained from the code regulations and iterative method is conducted. The results show that with the increase of the mean wind speed, the difference between the methods becomes bigger. On the other hand, based on the design of experiment (DOE), an approximate model is built for the optimal design of the large-scale cooling tower by a two-level optimization strategy, which makes use of code-based design method and the proposed iterative method. The results of the numerical example demonstrate the feasibility and efficiency of the proposed method.

SF6 Partial Discharge Decomposition Characteristics Under Different Lengths of Wire-Type Metal Particles in Direct Current Gas Insulated Equipment

Cao Zhengqin,Gang Wei,Zhou Yongjian,Bai Yichun,Hu Ding-Wen 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.2

Aiming at the serious defects of wire-type free metal particles, which can cause severe partial discharge (PD) in Direct current (DC) gas-insulated equipment, the experiments on the infl uence of four lengths (3.0, 5.0, 7.0, and 9.0 mm) of wiretype free metal materials on SF 6 decomposition under DC PD were conducted. The formation rules of four characteristic decomposition components, namely, CF 4 , SOF 2 , SO 2 F 2 and SO 2 , under diff erent lengths of wire-type free metal particles, were determined using gas chromatography. Results showed that the amounts of four kinds of SF 6 DC PD characteristic decomposition components are proportional to the length of wire-type free metal particles. The long length of wire-type free metal particles increases the intensity of PD and the amount and eff ective generation rates of SF 6 DC PD characteristic decomposition components. All these fi ndings provide an experimental basis for the diagnosis of insulation defect types in SF 6 DC gas insulated equipment.

Structural analysis and optimization of large cooling tower subjected to wind loads based on the iteration of pressure

Li, Gang,Cao, Wen-Bin Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.46 No.5

The wind load is always the dominant load of cooling tower due to its large size, complex geometry and thin-wall structure. At present, when computing the wind-induced response of the large-scale cooling tower, the wind pressure distribution is obtained based on code regulations, wind tunnel test or computational fluid dynamic (CFD) analysis, and then is imposed on the tower structure. However, such method fails to consider the change of the wind load with the deformation of cooling tower, which may result in error of the wind load. In this paper, the analysis of the large cooling tower based on the iterative method for wind pressure is studied, in which the advantages of CFD and finite element method (FEM) are combined in order to improve the accuracy. The comparative study of the results obtained from the code regulations and iterative method is conducted. The results show that with the increase of the mean wind speed, the difference between the methods becomes bigger. On the other hand, based on the design of experiment (DOE), an approximate model is built for the optimal design of the large-scale cooling tower by a two-level optimization strategy, which makes use of code-based design method and the proposed iterative method. The results of the numerical example demonstrate the feasibility and efficiency of the proposed method.