• Earthquakes and Structures
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• 제6권5호
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• pp.495-514
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• 2014

The performance of passive control system for the seismic protection of a multi-tower cable-stayed bridge with the application of partially longitudinal constraint system is investigated. The seismic responses of the Jiashao Bridge, a six-tower cable-stayed bridge using the partially longitudinal constraint system are studied under real earthquake ground motions. The effects of the passive control devices including the viscous fluid dampers and elastic cables on the seismic responses of the bridge are examined by taking different values of parameters of the devices. Further, the optimization design principle of passive control system using viscous fluid dampers is presented to determine the optimized parameters of the viscous fluid dampers. The results of the investigations show that the control objective of the multi-tower cable-stayed bridge with the partially longitudinal constraint system is to reduce the base shears and moments of bridge towers longitudinally restricted with the bridge deck. The viscous fluid dampers are found to be more effective than elastic cables in controlling the seismic responses. The optimized parameters for the viscous fluid dampers are determined following the principle that the peak displacement at the end of bridge deck reaches to the maximum value, which can yield maximum reductions in the base shears and moments of bridge towers longitudinally restricted with the bridge deck, with slight increases in the base shears and moments of bridge towers longitudinally unrestricted with the bridge deck.

• 한국정보통신학회논문지
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• 제10권2호
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• pp.392-397
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• 2006

본 논문에서는 ESP와 4WS차량의 동적성능에 관한 연구와 차량이 불안정 영역으로의 주행 시 안정영역으로의 거동으로 할 수 있게 하는 차량의 주행안정성 향상에 관한 연구를 수행하였다. 고속으로 주행하는 차량이 조향과 동시에 가${\cdot}$감속을 하는 경우 관련된 변수로는 종방향 및 횡방향의 속도변화, 요우잉 등을 들 수 있으며, 이 변수들은 타이어 특성, 차량의 중량, 제동력, 조향각등에 따른 동역학적 관계식들로 표현 할 수 있다. 본 연구는 위와 같은 제동${\cdot}$조향장치들을 제어하여, 차량의 주행 중 위급상황 시 탁월한 성능을 발휘 할 수 있는 시스템에 관하여 고찰하고, 주행시 안정성향상을 위한 제어시스템 알고리즘개발을 통하여 운전상황을 안전하게 하기 위함이다.

• 소성∙가공
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• 제23권6호
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• pp.369-375
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• 2014

Flexible roll forming allows profiles to have variable cross-sections. However, the profile may have some shape errors, such as, warping which is a major defect. The shape error is induced by geometrical deviations in both the concave zone and the convex zone. In the current study, flexible roll forming was modeled with FE simulations to analyze the shape error and the longitudinal strain distribution along the flange section over the profile. A distribution of analytically calculated longitudinal strains was used to develop relationships between the shape error and the longitudinal strain distribution as a function of the defined shape parameters for the profile. The FE simulations showed that the shape error is primarily affected by the deviations between the distribution of analytically calculated longitudinal strain and the longitudinal strain distribution of the profile. The results show that the shape error can be controlled by designing the shape parameters to control the geometrical deviations at the flange section in the transition zones.

• 대한본초학회지
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• 제25권1호
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• pp.75-81
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• 2010

Objectives : It was investigated new herbal prescription HT005 supported by traditional Korean medicine has a activity on the longitudinal bone growth of rats. HT005 were consisted of the root of Angelica sinensis, the fruit of Alpinia oxyphylla, the root of Astragalus membranaceus, the stem of Eleutherococcus senticosus, and the root of Dioscorea japonica, and Poria cocos. Method : To investigate the effect on longitudinal bone growth in adolescent male Sprague-Dawley rats, the longitudinal length of growth plate was measured directly by the tetracycline fluorescent labeling method and chondrocyte staining method. HT005 administered orally for four days, and the tetracycline was injected twice on the growth plate of the animals for fluorescent dying. The rate of longitudinal bone growth was measured the length between the tetracycline bands which fixed on the 3rd day and 5th day after injection. Cresyl violet was also used to stain the chondrocytes in the growth plate. The length of growth plate after administration was compared. Expression of IGF-1 and BMP-2 in the growth plate was investigated by immunohistochemistry. Results : HT005 showed a significant longitudinal bone growth which was $301.0{\pm}6.1\;{\mu}m/day$ at the dose of 100 mg/kg and $283.8{\pm}1.25\;{\mu}m/day$ (p < 0.001)at the dose of 10 mg/kg of HT005, compared to control group by the tetracycline fluorescent labeling method. HT005 showed a significant chondrocyte length on growth plate which was measured $797.19{\pm}3.31\;{\mu}m$ (p < 0.001) at the dose of 100 mg/kg and $720.14{\pm}2.19$ (p < 0.001) ${\mu}m$ at the dose of 10 mg/kg compared to the control group by cresyl-violet staining method. Both the number and intensity of BMP-2 and IGF-1 positive cells were increased in the hypertrophic zone of growth plate. There was a significant correlation between BMP-2 and IGF-1 expression and heights of chondrocytes in growth plate. Conclusions : Treatment of HT005 on Sprague-Dawley rats markedly increased the longitudinal bone growth. Therefore, HT005 may be an alternative herbal source to growth hormone as it promotes bone growth in children afflicted by growth retardation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.519-524
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• 2003

In this report, a longitudinal adaptive flight control law is presented for the automatic landing system of a Japanese automatic landing flight experiment vehicle (ALFLEX). The longitudinal adaptive flight control law is designed to track an output of the vehicle to a guidance signal from the guidance portion of the automatic landing system. The proposed adaptive control law in the attitude control portion adjusts the controller gains continuously online as flight conditions change, in spite of the existence of unmodeled dynamics. The number of the controller gains to be adjusted is decreased to 1/2 from the previous studies. Computer simulation involving six-degree-of-freedom (DOF) nonlinear flight dynamics is performed to examine the effectiveness of the proposed adaptive control law. In order to verify the influence of the dispersion of the initial conditions, the Monte Carlo simulation is also applied. The initial conditions are more widely dispersed than the previous studies. As a result, except under the unsuitable initial conditions, the ALFLEX successfully landed on the runway.

• 제어로봇시스템학회논문지
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• 제7권6호
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• pp.477-486
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• 2001

Many physical systems can be modeled by incorporating continuous and discrete event nature together. Such hybrid systems contain both continuous and discrete states that influence the dynamic be-havior of the systems. There has been an increasing interest in thers types of systems during the last dec-ade, mostly due to the growing usage of computers in the control of physical plants but also as a result of the hybrid nature of physical processes. The stability theory for hybrid systems is considered as extension of Lyapunov theory where the existence of an abstract energy function satisfying certain properties verifies stability, called multiple Lyapunov theory. In this paper, a hybrid stabilizing controller is proposed using the control Lyapunov function method and multiple Lyapunov theory, and the proposed method is applied to lon-gitudinal spacing control in a vehicle platoon for intelligent transportation systems(ITS).

• Journal of Mechanical Science and Technology
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• 제16권10호
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• pp.1253-1263
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• 2002

The control system design and modeling of an unmanned vehicle by means of a new concept for better performance through a tole-operation system is suggested by sensor fusion. But, the control of a real vehicle is very difficult, because the system identification of the vehicle is hard to find the unknown factors and the disturbances of the experimental environment. For the longitudinal and lateral controls, the traction system and steering system models are set up and a tuning method to find the gain of the controller by experiments is presented. In this research, mechanical and electronic parts are implemented to operate the unmanned vehicle and data reconstruction method of information about the environment data coming from several sensors is presented by data plot for the vehicle navigation. This paper focuses on the integration of tole-operated unmanned vehicle. This vehicle mainly controlled lateral and longitudinal directions with actuators for controlling vehicle movement and sensors for the closed-loop controlled system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2234-2236
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• 2001

This paper describes an implementation of a radiocontrolled airplane attitude control. To obtain the model of motion, stabilizing and control coefficients, we derive the related paramaters from aerodynamics, propulsion, gravity, wind correction and atmosphere. In this model, after separating longitudinal axis and lateral axis, we can get longitudinal axis model and lateral axis model by using actuator and dynamic characteristics of engine. From these two models, we experiment two divided parts-linear part, and nonlinear part.

• 대한간호학회지
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• 제48권1호
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• pp.109-121
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• 2018

Purpose: This study was conducted to examine the longitudinal effects of parenting stress and parental control attitudes on problem behaviors in preschool children, using a latent growth model. Methods: Participants were 1,724 pairs of parents and 1,724 preschool children who had completed the panel survey on Korean children ($5^{th}{\sim}7^{th}$ survey panels). Results: An analysis of the multivariate latent growth model of parenting stress, parental control attitudes, and children's problem behaviors suggested that the parents' intercepts for parenting stress influenced their intercepts for parental control attitudes (father: ${\beta}=.21$, p<.001; mother: ${\beta}=.55$, p<.001). In addition, the slopes for fathers' parenting stress was the only aspect that affected the slopes for mothers' parental control attitudes (${\beta}=.77$, p<.001). Moreover, both the intercepts and slopes of parenting stress and parental control attitudes significantly affected the children's problem behaviors. Conclusion: This study is significant as it provides longitudinal evidence of the impact of parenting stress and parental control attitudes on children's problem behaviors. The findings suggest that accurately assessing changes in parenting stress and parental control attitudes and developing intervention programs to reduce them will be effective in reducing problem behaviors in children.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.636-639
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• 1997

In this paper, a dynamic control scheme is proposed which not only compensates for the lateral dynamics and longitudinal dynamics but also deal with the yaw motion dynamics. Using the dynamic control technique, adaptive and learning algorithm together, the proposed controller is not only robust to disturbance and parameter uncertainties but also can learn the inverse dynamics model in steady state. Based on the proposed dynamic control scheme, a dynamic vehicle simulator is contructed to design and test various control techniques for 4-wheel steering vehicles.