• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.322-326
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• 1989

This paper describes design procedure of suboptimal control to minimize a performance index which is represented as sum of square output error and the heat input power in arc welding process. Heat input and temperature of a fixed point on the surface of the material are concerned as input and output of the process, repectively. The suboptimal control law considered here in is a proportional plus integral type and is implemented by using only the output variables available from sensor which is also optimally located in a fixed point w.r.t. a moving weld touch.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.333-336
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• 1997

In this paper, we present a nonlinear dynamic controller for position tracking of brushless dc motors. In constructing the controller, a backstepping-type approach is used under the condition of full state information, while an adaptive controller is adopted for parameter uncertainty throughout the entire electromechanical system. The nonlinear dynamic controller using the adaptive learning technique approach is shown to drive the state variables of system to the desired ones asymptotically and whose effectiveness is also sown via computer simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2120-2122
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• 2001

This paper describes a PID controller for an attraction type magnetic levitation system considering $H^{\infty}$ performance. PID controllers are a kind of fixed structure reduced order controllers. Using change of variables a reduced order control problem can be recast into a static output feedback control problem and can be solved efficiently by LMI(Linear Matrix Inequality) method. In this paper, cone complementarity method is adopted and the simulation shows good results.

• 한국유기농업학회지
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• 제28권3호
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• pp.289-313
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• 2020

This study was conducted to analyze the factors influencing participation intention in urban agriculture. The theoretical foundations of the study were Theory of Planned Behavior (TPB) and Pine and Gilmore's Experiencel Economy. The type of household composition was set as the moderating variable between these independent and dependent variables. In order to test the research model, hierarchical regression analysis was conducted on 439 effective respondents. The empirical analysis results are as follows. Educational experience factors, escapist experience factors, attitudes, subjective norm, and perceived behavioral control, which were set as independent variables to positive (+) influence participation intention in urban agriculture. In addition, the impact of their influence relationship was as follows : perceived behavioral control > attitudes > escapist experience factor > subjective norm > educational experience factor. On the other hand, as a result of analyzing the moderating effect according to the household composition, there was a significant difference in the effect of educational experiences, escapist experiences, and subjective norm on participation intention in urban agriculture. Significant results were not tested on the moderating effects between attitudes, perceived behavioral control, and participation intention in urban agriculture. Based on the results of this empirical analysis, academic and practical implications were presented.

• 가족자원경영과 정책
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• 제21권4호
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• pp.1-15
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• 2017

The purpose of this study was to identify the effect of satisfaction with the marriage support policy on marriage intention among unmarried employed men and women. The study subjects included 300 unmarried working men and women aged over 30 years residing in the Seoul metropolitan area. First, according to the analysis of the subjects' overall tendency towards satisfaction with the marriage support policy and towards marriage intention, the marriage support policy gained the highest level of support in relation to housing for newlywed couples, which scored 3.29 (sd=.93), followed by improvements in corporate and family culture for the purposes of work-family compatibility at 3.24 (sd=.95), wedding loans at 3.18 (sd=1.01), and the paid leave system for marriage preparation at 3.12 (sd=.88). These variables scored slightly higher than the median 3 points. Conversely, satisfaction with the availability of marriage-related information and the provision of opportunities for dating scored 2.65 (sd=.88) and 2.78 (sd=.80), respectively, both of which were slightly lower than the median of 3. The overall mean score for satisfaction with the marriage support policy was 3.03 (sd=.95), which was slightly higher than the median of 3. In regards to marriage intention, the score was 3.32 (sd=1.15) points out of a perfect score of 5, which was slightly higher than the median. This indicated a slightly higher level in terms of the subjects' intention to marry. Second, a hierarchical regression analysis was performed to identify the effect of satisfaction with the marriage support policy on marriage intention among unmarried employed adults. Sociodemographic variables were entered as control variables in the regression at the first stage, and variables relating to satisfaction in a family-friendly social environment were entered at the second stage. When gender, age, educational level, monthly income, period of employment, working hours, and type of employment were inserted in the first stage of regression as control variables, gender, monthly income, period of employment, and type of employment were found to have a significant effect on marriage intention. Marriage intention was found to be greater in unmarried men with higher monthly incomes and longer periods spent working, and in unmarried working men and women engaged in tenured employment work. When variables relating to satisfaction with the marriage support policy were inserted in the second stage of regression, gender, monthly income, type of employment, and satisfaction with direct marriage support had significant effects on marriage intention. It was found that marriage intention was greater in unmarried men whose monthly income was higher, whose employment type was tenured work, and who showed greater satisfaction with direct marriage support.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1053-1059
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• 2009

Construction system modeling can enhance work performance by following the behaviors of a system. System behaviors may originate from physical aspects of a system, namely operation level variables, or from non-physical aspects of a system known as context level variables. However, construction system modelers usually focus on only one type of system variable (i.e., operation level or context level) which can lead to less accurate results. Hybrid modeling with System Dynamics (SD) and Discrete Event Simulation (DES) is one of the approaches that has been utilized to address this issue. In this research, an SD-DES hybrid model of a steel fabrication shop is developed, and the benefits of capturing context level variables together with operation level variables in the model are discussed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.422-422
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• 2000

Parallel manipulators have been used to a variety of applications, including the motion simulators and mechanism for precise machining. A Stewart-Gough type parallel manipulator is composed of six linear joints which have wider contact areas than revolute ones, so linear joints are more affected by frictional force. First, the reference trajectories are computed from the model of the parallel manipulator assuming that it is subject to only the gravitational force and no friction exists. In the actual operation where friction exists, the control inputs, which correspond to the friction forces, are obtained by forcing the actual joint variables to follow these trojectories by proper control. It is shown that control performance can be improved when the friction compensation based on this information is added to the controller for position control of the moving plate of a parallel manipulator.

• 제어로봇시스템학회논문지
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• 제8권3호
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• pp.233-242
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• 2002

A kinematic modeling method is proposed which models the sliding and skidding at the wheels as pseudo joints and utilizes those pseudo joint variables as augmented variables. Kinematic models of various type of wheels are derived based on this modeling method. Then, the transfer method of augmented generalized coordinates is applied to obtain inverse and forward kinematic models of mobile robots. The kinematic models of five different types of planar mobile robots are derided to show the effectiveness of the proposed modeling method.

• 대한수학회지
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• 제50권1호
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• pp.81-93
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• 2013

We consider a distributed optimal flux control problem: finding the potential of which gradient approximates the target vector field under an elliptic constraint. Introducing the Lagrange multiplier and a change of variables the Euler-Lagrange equation turns into a coupled equation of an elliptic equation and a reaction diffusion equation. The change of variables reduces iteration steps dramatically when the Gauss-Seidel iteration is considered as a solution method. For the elliptic equation solver we consider the Cell Boundary Element (CBE) method, which is the finite element type flux preserving methods.

• 문화기술의 융합
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• 제10권2호
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• pp.531-536
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• 2024

최근 농업분야의 스마트 농기계로 분류되고 있는 방제드론은 농촌지역의 고령화 시대를 맞이하여 작업 시간 단축과 방제효과를 높이기 위해 하드웨어 및 소프트웨어를 결합하여 스마트 방제 및 자동방제 시스템 구축을 위해 노력하고 있다. 본 논문에서는 관리관제 및 자동방제 시스템 구축을 위한 기초연구로 방제드론 전용노즐의 특성을 분석하였다. 다양한 드론 모델의 종류, 방제사, 바람, 비행속도, 비행고도, 날씨 조건, UAV 농약 종류 등 다양한 변수를 고려하기 위해서는 노즐의 특성파악과 범용성을 고려하여 약제살포 기준 제시가 가능한 관련 연구가 필요하다. 따라서 다양한 변수 고려가 가능하도록 자체 설계노즐을 기반으로 유동해석(CFD) 시뮬레이션을 실시하고 감수지 실험을 통하여 액적분포의 이론값과 실험값을 비교 분석하였다. 추후 드론운용에 따른 다양한 변수를 고려하여 정확한 비산을 산출하고 관리관제 및 자동방제 시스템에 활용하고자 한다.