• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.547-551
• /
• 1996

In this paper, robust vibration control of a one-link flexible robot arm based on variable structure system is discussed. We derive dynamic equations of it using a Lagrangian assumed modes method based on Bernoulli-Euler Beam theory. The optimal sliding surface is designed and the problem of chattering is also solved by the adoption of a continuous control law within a small neighborhood of the switching hyperplane.

• Proceedings of the IEEK Conference
• /
• 1999.11a
• /
• pp.703-706
• /
• 1999

In this paper, robust vibration control of a one-link flexible robot arm based on variable structure system is discussed. We derive dynamic equations of it using a Lagragian assumed modes method based on Bernoulli-Euler beam theory. The optimal sliding surface is designed and the problem of chattering is also solved by the adoptation of a continuous control law within a small neighborhood of the switching hyperplane.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10a
• /
• pp.451-456
• /
• 1990

We treat the problem of the robust tracking of a class of nonlinear systems which can be asymptotically decoupled in approximate sense by state variable feedback. A nonlinear control law is derived such that the tracking error in the closed loop system is uniformly bounded and tends to a certain small neighborhood of the origin. Simulation results show that simultaneous lateral and longitudinal maneuvers in airplane can be accurately performed in spite of uncertainty in stability derivatives.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.4
• /
• pp.27-34
• /
• 1989

An adaptive model following controller is designed using the theory of variable structure systems. The proposed method based on the modified condition for the sliding mode allows the designer to satisfy the requirements to speed up the reaching phase and for the magnitude of the chattering to be reduced in the sliding mode. Chattering reduction is obtained by the replacement of control input in the neighborhood of the sliding plane. The results of computer simulation show that state trajectories reach switching plane fast and chattering is reduced.

• Health Policy and Management
• /
• v.21 no.2
• /
• pp.329-348
• /
• 2011

This research analyzed 168,010 cases of death of the aged over 65 from 244,867cases of death excluding 7 unknown age cases from 244,874 all age cases of death by using the death data of the National Statistical Office for 2007 to figure out factors affecting the quality of causes of death statistics of the aged and to suggest the ways of improving the quality of death statistics of the aged in korea. This research tried to derive factors affecting ill-defined cause of death category in acordance with WHO's guidelines and to find causes of lowering the accuracy of causes of death statistics of the aged. This research identified the problems of causes of death statistics of the aged by using both demographic characteristics such as sex, age, marital status, educational attainment, residential region, region size and factors of death items as independent variable to find causes of ill-defined cause of death of the aged. Logistic regression analysis was executed to calculate the hazard ratio about the ill-defined causes of death of the aged and multiple regression analysis was conducted to derive factors affecting the ill-defined cause of death by regional groups through using these independent variables such as the component ratio of over age 65, female death rates, doctors insitutions rate, medical institutions rate, attaching rates of death certificate by neighborhood. As a results of this research, R-code was the highest of ill-defined causes of death, accounting for 82.1%, and senility death(R54) of R-code was the highest, accounting for 91.2%. through subdivided order distribution of the ill-defined causes of death of the aged. As ill-defined causes of death by regional groups, attaching rates of death certificate by neighborhood was the most important factor(p<0.05) and also showed regression model's description with 83.8% ($R^2$=83.8%). Furthermore, Jeon-nam was the highest in the regional groups and these regions such as Je-ju, Jeon-buk, Chung-nam were not only attaching the death certificate by neighborhood but also were high at the rate of ill-defined causes of death. Therefore, this research found that both reconsideration about death certificate by neighborhood and education for doctors who write death certificate were needed the most.

• Korean Journal of Social Welfare
• /
• v.58 no.4
• /
• pp.265-289
• /
• 2006

Purpose of this research is to analyze process that poverty influences in academic attainment of children. Data comes from Korea Youth Panel Survey 2004(Primary School 4). Analysis method is Structural Equation Modeling. Results show that poverty influences through process variable such as family function, neighborhood environment, private education, self-confidence. Findings from this study suggest that societal support for poor families contributes to improving academic attainment of child. Specially, such societal support needs to be centered to factors that mediates factor of poverty.

• Journal of the Korean Home Economics Association
• /
• v.45 no.7
• /
• pp.71-91
• /
• 2007

We investigated the ecological variables of adolescent sexual behavior. We grouped the behaviors into organism, microsystem, mesosystem, and exosystem. The variables belonging to the organism group were sexual attitude, sex, grade, sexual knowledge, sexual education, dating experience, problem behaviors, and self-control. The microsystem variables included the parent-adolescent communication about sexuality, parental monitoring, parent educational background, friend relationships, and school environment. Moreover, the mesosystem variables included family-peer and family-school relationships. The exosystem variables were comprised of neighborhood environment and pornography. The study group included 369 adolescents from the first and second grade of several high school in Daegu, Korea. We found that the factors affecting adolescent sexual behavior included grade, sex, dating experience, self-control, smoking, and pursuing sexual pleasure. As well, contact with deviant friends, father-adolescent communication about sexuality, school type, and attachment to teacher. In addition the family-peer relationship also affected adolescent's sexual behaviors as well as pornography and neighborhood environment. Lastly the variable belonging to the organism group was found to have the greatest effect on adolescent, sexual behavior compared to the other variables.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.6
• /
• pp.142-155
• /
• 2000

A MIMO model reference control scheme incorporating the variable structure theory for a vehicle four wheel steering system(4WS) is proposed and evaluated for a class of continuous-time nonlinear dynamics with known or unknown uncertainties. The scheme employs an neural network to identify the plant systems, where the neural network estimates the nonlinear dynamics of the plant. By the Lyapunov direct method, the algorithm is proven to be globally stable, with tracking errors converging to the neighborhood of zero. The merits of this scheme is that the global system stability is guaranteed and it is not necessary to know the exact structure of the system. With the resulting identification model which contains the neural networks, it does not need higher degrees of freedom vehicle model than 3 degree of freedom model. Th proposed scheme is applied to the active four wheel system and shows the validity is used to investigate vehicle handing performances. In simulation of the J-turn maneuver, the reduction of yaw rate overshoot of a typical mid-size car improved by 30% compared to a two wheel steering system(2WS) case, resulting that the proposed scheme gives faster yaw rate response and smaller side angle than the 2WS case.

• 재활복지
• /
• v.21 no.1
• /
• pp.71-95
• /
• 2017

The purpose of this research is to suggest implications for the elderly with disability by taking a look at the influence of disability of elderly on successful aging and a moderating effect of social support network. This study analyzed the $4^{th}$ panel data from KReIS and the subjects for this research are 3,906 of elderly aged over 65 years. For the statistical analysis, the IBM SPSS Statistics v23.0 program was utilized. Technical statistics was verified, multiple regression analysis was used in order to take a look at the effects of moderating variable. The results of this research are as the following: Firstly, the disability of elderly had an negative effect on successful age. Secondly, as a social support network, friend & neighborhood network and family network had an positive effect on successful age. Thirdly, friend & neighborhood network among social support network had a moderating effect on successful aging. In other words, the more disabled the elderly are, the lower the level of successive aging became, it turned out that the bigger the social support of friend & neighborhood network, the less the negative effect of disability on successive aging. On the basis of the result, it was proposed a case management for the elderly with disability, assurance of mobility right, and self-help meeting program for social support network.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1997.04a
• /
• pp.131-136
• /
• 1997

This paper represent the variable structure adaptive mode control technique which is new approach to implement the robust control of industrial robot manipulator with external disturbances and parameter uncertainties. Sliding mode control is a well-known technique for robust control of uncertain nonlinear systems. The robustness of sliding model controllers can be shown in contiuous time, but digital implementation may not preserve robustness properties because the sampling process limits the existence of a true sliding mode. the sampling process often forces the trajectory to oscillate in the neighborhood of the sliding surface. Adaptive control technique is particularly well-suited to robot manipulators where dynamic model is highly complex and may contain unknown parameters. Adaptive control algorithm is designed by using the principle of the model reference adaptive control method based upon the hyperstability theory. The proposed control scheme has a simple sturcture is computationally fast and does not require knowledge of the complex dynamic model or the parameter values of the manipulator or the payload. Simulation results show that the proposed method not only improves the performance of the system but also reduces the chattering problem of sliding mode control, Consequently, it is expected that the new adaptive sliding mode control algorithm will be suited for various practical applications of industrial robot control system.