http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Duc-Thien Tran,Hoai Vu Anh Truong,Kyoung Kwan Ahn 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.3
The paper addresses an adaptive robust position control for tracking control of a manipulator under the presence of the uncertainties, such as variant payload, modeling error, friction, and external disturbance. The proposed control uses radial basis function neural networks (RBFNN)s to approximate and cancel the uncertainties. The nonsingular fast terminal sliding mode control (NFTSMC) of the proposed control is developed to guarantees a finite-time convergence and to solve the singular issue of the terminal sliding mode control. Moreover, the learning laws are derived from the Lyapunov approach to ensure the stability and robustness of the whole system. The proposed control is compared with other controllers through both simulations and experiments on a 3-DOF manipulator to exhibit its efficiency with the variant payload and the uncertainties.
ALMA OBSERVATIONS OF W HYDRAE: IMPACT OF MISSING BASELINES
Do Thi Hoai,Tuan-Anh Pham,Pham Tuyet Nhung,Pierre Darriulat,Pham Ngoc Diep,Nguyen Bich Ngoc,Tran Thi Thai 한국천문학회 2021 Journal of The Korean Astronomical Society Vol.54 No.6
The lack of short baselines, referred to as the short-spacing problem (SSP), is a well-known limitation of the performance of radio interferometers, causing a reduction of the flux detected from source structure on large angular scales. The very large number of antennas operated in the Atacama Large Millimeter/sub-millimeter Array (ALMA) generates situations for which the impact of the SSP takes a complex form, not simply measurable by a single number, such as the maximal recoverable scale. In particular, extended antenna configurations, complemented by a small group of closeby antennas at the centre of the array, may result in a double-humped baseline distribution with a significant gap between the two groups. In such cases one should adopt as the effective maximal recoverable scale the one associated with the extended array and use only the central array to recover missing ux, as one would do with single dish or ACA (Atacama Compact Array) observations. The impact of the missing baselines can be very important and may easily be underestimated, or even overlooked. The present study uses ALMA archival data of the ^{29}SiO(8-7) line emission of the AGB star W Hydrae for a demonstration. A critical discussion of the reliability of the observations away from the star is presented together with comments of a broader scope. Properties of the circumstellar envelope of W Hya within ~15 au from the star, many of which are not mentioned in the published literature, are briefly described and compared with R Doradus, an AGB star having properties very similar to W Hya.
Adaptive sliding mode control with backstepping technique for hydraulic manipulator
Duc-Thien Tran,Hoai Vu Anh Truong,Xuan Dinh To,Bomoon Seo,Kyoung Kwan Ahn 제어로봇시스템학회 2018 제어로봇시스템학회 국내학술대회 논문집 Vol.2018 No.5
In this paper, an adaptive sliding mode control with backstepping technique is proposed regarding to controlling position of a hydraulic manipulator in joint space. The proposed control is developed based on sliding mode control, backstepping technique, and radial basis function neural network (RBFNN). In the hydraulic manipulator, the primary torques are generated by hydraulic actuators, so it helps to extend load carrying capacity of the manipulator. But it brings some challenges, such as coupling issues, uncertainties in parameter, modeling, and external disturbance in mechanical and hydraulic dynamics. The properties of the proposed control can deal to these problems to guarantee the stability requirements and improve the precision. The sliding mode control with backstepping technique is used to handle the coupling issues and to ensure the stability and robustness. Additionally, two adaptive approximators based on RBFNN compensate the uncertainties and improve the precision. Some simulations are implemented and compared to other controllers to exhibit the effectiveness of the proposed control.
An Exploratory Study of Factors Affecting Customer’s Satisfaction on Online Shopping
Duong Tan Phat,Tran Thi Hong Anh,Dang Nguyen Hoai Thu,Nong Thi Nhu Mai 한국유통과학회 2017 KODISA ICBE (International Conference on Business Vol.2017 No.-
In contemporary century - the century of Internet, E-commerce is more and more important. Few years ago, buying things on the Internet was still strange to Vietnamese people, but nowadays, they become a vital part of many consumers’ personal social life. Vietnamese people can buy almost every type of products on the Internet; however, their trust in online shopping is very tenuous. This paper identifies the factors that the online shopping enterprises need to focus on, which are Logistic services quality, Websites quality, Product quality, and Brand, in order to conquer the satisfaction of Vietnamese customers. By gathering information from 205 people at every ages and genders in Ho Chi Minh city, Vietnam via questionnaire, this research will apply deductive approach with quantitative research to testify the pre-assumed hypothesis. This study will contribute to understanding the consumers’ behaviors about buying things on Internet, as well as knowing how to gain the satisfaction of online customers. The weakness of this paper is the smallness of data collected for the survey, therefore, the will be an expansion of samples collected in the further research.
Le-Phuc Nguyen,Yen Thi Hai Pham,Phuong Thuy Ngo,Tri Van Tran,Loc Vinh Tran,Nam Thi Hoai Le,Luong Huu Nguyen,Tung Thanh Dang,Duc Anh Nguyen,Marco Wenzel,David Hartmann,Karsten Gloe,Jan J. Weigand,Klaus 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.5
Acid leaching and a two-step solvent extraction procedure were developed to produce high purity mixture of La and Ce from iron-rich spent FCC catalyst discharged from Dzung Quat refinery (Vietnam). Acid leaching of the spent catalyst with 2M HNO3 and a solid-to-liquid ratio of 1/3 at 80 oC in 1 h dissolved almost 90% of La while 12% of Al and 25% of Fe were transferred to the leachate. The extraction of RE metals and main impurities such as Al and Fe by a mixture of di-2-ethylhexyl phosphoric acid (D2EHPA) and tributyl phosphate (TBP) was investigated. Experiments showed that it was necessary to remove Fe before extracting RE and the optimum extraction conditions for a high recovery of RE while 0% of Al extraction were pH1, contact time=10min, and D2EHPA/TBP volume ratio= 4 : 1. At these conditions, the extraction yields of La(III) and Ce(III) were 72% and 89%, respectively. A two-step solvent extraction was developed to achieve a high purity of RE mixture, which included (1) the removal of impurity Fe by 25% (v/v) diisooctyl phosphinic acid (DiOPA) in n-octane for 140 min, (2) the extraction of rare earths by a mixture of di-2-ethylhexyl phosphoric acid (D2EHPA) and tributyl phosphate (TBP) in n-octane for 10 min without the need for adjusting the pH of the leaching solution.