The boundedness of some bilinear singular integral operators on Besov spaces

Ming Xu 대한수학회 2006 대한수학회지 Vol.43 No.2

In this paper we weaken the kernel conditions of bilinear Calder$\acute{o}$n-Zygmund operators and prove boundedness on Besov spaces.

Modeling and Residual Vibration Control of a Quayside Container Crane

Mingxu Piao,Umer Hameed Shah,Sang-Hei Choi,Keum-Shik Hong 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10

This paper discusses the mathematical modeling and residual vibration control problem of a quayside container crane, which is one of the automated handling equipment for containers at a seaport. The main purpose of the quayside crane is the safe loading and un-loading of the container ships in quick time. The residual vibrations of the transported containers cause operational delays and therefore must be suppressed, which can be achieved by implementing an appropriate control strategy. Generally, the control strategies are based on a simplified model of a conventional container crane (i.e., assuming a single-rope hoisting mechanism). However, in this paper, we have derived the mathematical model of the quayside crane based on the actual (i.e., multi-rope) hoisting mechanism. An open-loop control is then applied to generate shaped trolley-drive commands to transport the containers to the desired locations while suppressing their residual vibrations. Furthermore, a closed loop control is also developed to suppress the vibrations of the containers due to initial conditions and disturbances. The validity of the proposed control laws has been demonstrated by performing simulations.

중국 내 한·일 사회과학 연구 이슈 분석 - CSSCI 데이터베이스의 Citespace 시각화 분석을 기반으로

MINGXU CUI,장묘탁 MIAOZHUO ZHANG 계명대학교 한국학연구원 2023 한국학논집 Vol.- No.90

Based on the quantitative analysis of 13432 and 2458 articles related to the theme of " Korean Studies" and " Japanese studies", this paper uses the CiteSpace to compare and analyze from the perspectives of keyword co-occurrence, co-citation, burst, clustering and so on. The results show that the research on economy, education and the correlation with China are the focus of the research on Korea and Japan. "Korean film", "localization" and "Korean diplomacy" are the research hotspots in the field of Korean studies in recent years, and "Rural revitalization", "Japan-US alliance", "artificial intelligence" and "Indo-Pacific strategy" are the research hotspots in the field of Japanese studies in recent years. At present, the Korean study circle pays more attention to the history and culture, while the Japanese study circle pays more attention to the foreign policy and national strategy of the Japanese government, the agricultural economy and rural revitalization of Japan. 본 연구는 '한국 연구'와 '일본 연구' 주제와 관련된 각각 2,458편과 13,432편의 문헌을 측정 분석하고, CiteSpace 시각화 소프트웨어를 사용하여 동시출현단어, 공피인용, 상위출현, 클러스터링 등의 관점에서 한·일 연구를 비교 분석하였다. 이를 통하여, 중국 내 학계의 한·일 지역 양상을 고찰하고자 하였다. 연구 결과에 따르면 경제, 교육 분야 및 중국과 관련된 연구는 모두 중국 낸 한·일 연구의 핵심 분야이다. '한국영화' '현지화' 및 '한국 외교'는 최근 몇 년간 한국 연구의 핵심 분야이며 , '농촌 진흥' '미일 동맹' '인공지능' 및 '인도·태평양 전략'최근 몇 년간 일본 연구의 핵심 분야이다. 현재 한국 연구 학계는 역사, 문화에 관해 관심이 높지만, 일본 연구 학계는 일본 정부의 외교정책 및 국가전략, 일본의 농업경제 및 농촌 진흥에 주목하고 있다.

Super-twisting Sliding Mode Control of Container Cranes With Triangle-trapezoid Rope Reeving System

Mingxu Piao,Keum-Shik Hong,Muhammad Umer Hameed Shah,Guanghao Huang 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.1

In this paper, the dynamics of a new type of container crane, in which eight ropes connect the trolley and spreader in a triangle-trapezoid shape, is developed. The triangle-trapezoid cable configuration for connecting the spreader with the trolley is introduced to reflect the dynamic aspects of the multi-rope reeving system. A supertwisting sliding mode control for the developed model is designed for accurate trolley position control and vibration suppression of the load. Due to its robustness property against external disturbance, satisfactory control performance is achieved. Finally, experimental results to validate the developed model and simulation results to verify the control algorithm are also provided in this study.

노신문학과 정치관계의 소고

mingxue Li 단국대학교 법학연구소 2017 법학논총 Vol.41 No.3

This study focuses on Lu Xun’s(1881-1936) influence and achievement on Chinese society and politics through the review of relationship between his literature and politics. During the transition from his adolescent evolutionist to the materialist in his middle age, Lu Xun absorbed virtues and strengths widely from various ideas and ideologies such as nationalism, Enlightenment, democracy and communism. Not only did he understood the relationship between literature and politics simply as antagonistic or obedient to each other, but practiced actively in perspective of dialectical philosophy, maximizing the social and political functions of literature. In this regards, his literary work remained as a shining role till today for realizing the “China’s dream” in the era of reform and opening and eradication of corruption of the China. 본고에서는루쉰문학과정치의관계문제에대한고찰을통하여그의문학이중국사회와정치에대한영향및그공적을새롭게가늠해보고자한다.청년시기의진화론자로부터중년시기의유물론자로의전변과정에서루쉰은민족주의,계몽주의,민주주의,공산주의등여러사상및사조유들의장점을두루섭취하였다.루쉰은문학과정치의관계를단순이서로대립하거나순종하는관계로이해한것이아니라변증법적인철학적시각에서능동적으로이해하고실천하여문학의사회정치적기능을최대한확대하였다.이런의미에서오늘날중국의개혁개방시대의‘중국의꿈’의실현과부정부패를척결하는사업에서그의문학은여전히훌륭한귀감으로될것이다

Deformation Characteristics and Sealing Performance of Metallic O-rings for a Reactor Pressure Vessel

Shen, Mingxue,Peng, Xudong,Xie, Linjun,Meng, Xiangkai,Li, Xinggen Korean Nuclear Society 2016 Nuclear Engineering and Technology Vol.48 No.2

This paper provides a reference to determine the seal performance of metallic O-rings for a reactor pressure vessel (RPV). A nonlinear elastic-plastic model of an O-ring was constructed by the finite element method to analyze its intrinsic properties. It is also validated by experiments on scaled samples. The effects of the compression ratio, the geometrical parameters of the O-ring, and the structure parameters of the groove on the flange are discussed in detail. The results showed that the numerical analysis of the O-ring agrees well with the experimental data, the compression ratio has an important role in the distribution and magnitude of contact stress, and a suitable gap between the sidewall and groove can improve the sealing capability of the O-ring. After the optimization of the sealing structure, some key parameters of the O-ring (i.e., compression ratio, cross-section diameter, wall thickness, sidewall gap) have been recommended for application in megakilowatt class nuclear power plants. Furthermore, air tightness and thermal cycling tests were performed to verify the rationality of the finite element method and to reliably evaluate the sealing performance of a RPV.

입력성형기법을 이용한 핵연료이송시스템의 수중이동 시의 진동제어

박명욱(Mingxu Piao),샤 우머 하미드(Umer Hameed Shah),전재영(Jae Young Jeon),홍금식(Keum-Shik Hong) 제어로봇시스템학회 2014 제어·로봇·시스템학회 논문지 Vol.20 No.4

In this paper, residual sway control of objects that are moved underwater is investigated. The fuel transfer system in a nuclear power plant transfers the nuclear fuel rods underwater. The research on the dynamics of the loads transferred in different mediums (water and air) and their control methods have not been fully developed yet. The attenuation characteristics of the fuel transfer system have been studied to minimize its residual vibration by considering the effects of hydrodynamic forces acting on the fuel rod. First, a mathematical model is derived for the underwater fuel transfer system, and then experiments have been conducted to study the dynamic behavior of the rod while it travels underwater. Lastly, the residual vibration at the end point is minimized using the input shaping technique.

Input Shaping 기술을 이용한 핵연료이송시스템의 수중이동 시의 진동제어

박명욱(Mingxu Piao),샤 우마 하미드(Umer Hameed Shah),전재영(Jae Young Jeon),홍금식(Keum-Shik Hong) 제어로봇시스템학회 2013 제어로봇시스템학회 각 지부별 자료집 Vol.2013 No.8

핵연료이송장치는 원자력발전소에서 사용되는 핵연료봉을 이송하는 장비로써, 핵연료의 특성상 그 이동이 수중에서 이루어져야 한다. 현재까지 대기(大氣) 상태에서의 화물이송에 관한 이론 및 시스템은 오랫동안 연구되어 왔으나 매질(수중 혹은 대기중)에 따른 이송장치의 동특성 및 최적제어에 관한 연구는 활발히 이루어 지지 않고 있다. 본 논문은 물속의 저항성분을 고려하여 마스트의 진동을 줄이기 위해 핵연료이송장치의 구동시스템을 파악하고자 하였다. 먼저, 수중 이송시스템의 수학적 모델을 구축하였다. 그리고 수조실험을 통해서 시스템 수평운동 시 발생하는 진동을 해석을 하였다. 마지막으로 연료봉의 진동을 줄이기 위해 Input Shaping 방법을 적용하고, 이에 따른 시간최적제어를 유도하였다.

오버헤드셔틀시스템의 동특성해석 및 잔류진동제어

박명욱(Mingxu Piao),김경한(Gyoung-Hahn Kim),Umer Hameed Shah,홍금식(Keum-Shik Hong) 제어로봇시스템학회 2016 제어·로봇·시스템학회 논문지 Vol.22 No.6

This paper discusses the dynamics and control problem of an overhead shuttle system (OSS), which is a critical part of the automated container terminal at a port. The main purpose of the OSS is efficient automated transport function of containers, which also requires high precision and safety. A major difference between the OSS and the conventional container crane is the configuration of the cables for hoisting the spreader. A mathematical model of the OSS is developed here for the first time, which results in an eight-pole system. Also, open loop control methods (trapezoidal and notch-type velocity profiles) are investigated so that the command input to the overhead shuttle produces the minimum possible sway of the payload. Simulation results show that the vibration suppression capability of the OSS is superior to the conventional overhead container crane, which is partially due to the cable configuration.

해양크레인시스템의 수정된 2차 슬라이딩모드제어

박명욱(Mingxu Piao),김경한(Gyoung-Hahn Kim),홍금식(Keum-Shik Hong) 제어로봇시스템학회 2018 제어·로봇·시스템학회 논문지 Vol.24 No.10

In this paper, a super-twisting (i.e., modified 2nd-order) sliding mode control (STSMC) is proposed for sway control of an offshore container crane system (i.e., a mobile harbor system equipped with a container crane on it). The mobile harbor is used for ship-to-ship transfer of containers, where the container ship is anchored in an open sea. To load/unload the containers in an open sea, it is necessary to suppress the position error of the load caused by the wave-induced movements of the mobile harbor. In this paper, a super-twisting sliding mode controller is developed for suppressing the position error of the payload. The sliding surface is designed in such a way that the longitudinal sway of the load is incorporated within the trolley dynamics. The chattering problem is also solved by utilizing a second order sliding surface. Lyapunov function-based stability analysis is performed to prove the uniform stability of the closed-loop system. Simulation results are provided to prove the effectiveness of the proposed control law.