• Journal of the Korean Home Economics Association
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• v.33 no.3
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• pp.113-126
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• 1995

The purposes of this study were to investigated ; 1) The amount of shared leisure time with spouses. 20 The differences of the mount of shared leisure time according to socio-demographic variables. 3) The relationship between marital satisfaction and the amount of shared leisure time. Data for 291 couples were gather from using structured questionnaire and time diary. The major findings were ; 1) Spouses spent together 2 hours and 8 minutes on the average per day in leisure. Time for active leisure was 1 hour and 36 minutes, while that for passive leisure was 32 minutes. 2) The total shared leisure time were significantly related to husband's age, degree of husband's education, and employment status of wife. The active shared leisure time were related number of children and husband's age. and the passive shared leisure time were related to degree of husband's education, and employment status of wife. 3) The more couples spent together in leisure, the higher their marital satisfaction became.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1219-1224
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• 2007

This is Presents experimental results of a force tracking controller for a quarter-car suspension system. The active suspension system was decomposed into two loops. At the main loop, the desired force signal is calculate by using a standard LQ design process. The Time Delay Control(TDC) design technique is then used to design the force controller such that the desired force signal is achieved in a robust manner when actuator or other plant uncertainties are present. The ADAMS controls module was used to realize the joint simulation of ADAMS and MATLAB, of which the results showed that the TDC strategy is reasonable and feasible.

• Journal of KSNVE
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• v.8 no.4
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• pp.683-689
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• 1998

A control algorithm for multi-stage dampers is developed based on the mode skyhook control concept, and implemented on the full vehicle system environment. The test vehicle system is equipped with the real time controller, four-stage variable dampers and sensors. The real time controller is developed using a digital signal processor(DSP), digital I/O, A/D and D/A converters. The dampers are driven by the electromagnetic actuators of less than 20 msec response time. The sensors include accelerometers, relative displacement transducers, and steering wheel rate sensors, etc. Through a series of tests in laboratory and proving ground, the performance of the semi-active suspension system is evaluated and it is shown that the vehicle dynamic characteristics is improved with the developed damping system. Futhermore, the parameter tuning methods to enhance vehicle dynamic performance are propsoed.

• Smart Structures and Systems
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• v.15 no.3
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• pp.863-879
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• 2015

This paper experimentally investigates the effectiveness and applicability of the time delay control (TDC) algorithm, which is simple and robust to unknown system dynamics and disturbance, for an active mass damper (AMD) system to mitigate the excessive vibration of a building structure. To this end, the theoretical background including the mathematical formulation of the control system is first described; and then, a thorough experimental study using a shaking table system with a small-scale three-story building structural model is conducted. In the experimental tests, the performance of the proposed control system is examined by comparing its structural responses with those of the uncontrolled system in the free vibration and forced vibration cases. It is clearly verified from the test results that the TDC algorithm embedded AMD system can effectively reduce the structural response of the building structure.

• Journal of the Semiconductor & Display Technology
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• v.10 no.1
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• pp.83-89
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• 2011

In the case of the tracking system with an active camera, it is very difficult to guarantee real-time processing due to the attribute of vision system which handles large amounts of data at once and has time delay to process. The reliability of the processed result is also badly influenced by the slow sampling time and uncertainty caused by the image processing. In this paper, we figure out dynamic characteristics of pixels reflected on the image plane and derive the mathematical model of the vision tracking system which includes the actuating part and the image processing part. Based on this model, we find a controller that stabilizes the system and enhances the tracking performance to track a target rapidly. The centroid is used as the position index of moving object and the DC motor in the actuating part is controlled to keep the identified centroid at the center point of the image plane.

• Journal of Aerospace System Engineering
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• v.13 no.5
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• pp.9-15
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• 2019

In this paper, dynamic analysis of a nonlinear active vibration absorber is conducted with a time delay acceleration feedback to suppress the vibration of a nonlinear single degree of freedom primary system. The primary system consisting of linear and nonlinear cubic springs, mass, and damper is subjected to the multi-harmonic hard excitation with a parametric excitation. It is proposed to reduce the vibration of the primary system and the absorber by using a lead zirconate titanate (PZT) stack actuator in series with a spring in the absorber which configures as an active vibration absorber. The method of multiple scales (MMS) is used to obtain the approximate solution of the system under the internal resonance, subharmonic, superharmonic, and principal parametric resonance conditions simultaneously. Frequency and time responses of the system are investigated considering a delay in the feedback for the various parameters of the absorber configuration and controlling force.

• Korean Journal of Community Nutrition
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• v.16 no.3
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• pp.307-314
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• 2011

The purpose of this study is finding the easy way of 4 categories activity level confirmation for estimated energy requirement calculation. Total of 386, 5th and 6th grade primary school students participated. The time spent on 7 kinds of activity were collected for 1 day by the internet program developed. Judged by the activity coefficient, sedentary were 6.7% and 5.1%, low active 33.2% and 40.4%, active 43.8%, and45.5%, and very active 16.3% and 9.0% for boy and girl, respectively. The highest and significant correlation coefficient between activity coefficient and time spent on activities shown were 0.339 in commute activity for boys, and 0.466 in leisure for girls. The sensitivity of the sedentary conformation by commute hour for boys was 0.79, and that of very active was 0.56. The sensitivity of the sedentary conformation by leisure hour for girls was 0.67, and that of very active was 0.63. The sensitivity of low active and active by 7 different types of activity was quite low, 0.04~0.37. The exact agreement of activity level conformed by easy way developed was 30.8% and 33.7%, for boys and girls, respectively. More accurate way to identify 4 categories activity level needs to be developed, especially sensitive to conformation of low active and active levels.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1411-1414
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• 2003

In this paper, vehicle tracking is implemented using parametric active contour. Extract objects from the background area is the essential step in vehicle tracking. We focus our algorithm on the situations such that the camera is fixed. However, if a simple and ordinary algorithm is adapted to achieve real-time processing, it produces much noise and the vehicle tracking results is poor. For this reason, in this paper, we propose a parametric active contour model algorithm to achieve better vehicle tracking. Experimental results show that the performance of the proposed algorithm is satisfactory.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.367-372
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• 2007

현재 펜기반 컴퓨팅 환경에서 주로 쓰이는 문자 입력 방식은 화상키보드이다. 그러나 화상키보드는 펜 컴퓨터를 위해 나온 것이 아니기에 차지하는 화면의 크기나 움직임 거리등의 문제가 있다. 본 논문에서는 그러한 단점을 개선하기위하여 모바일 장치의 키패드를 이용하여 새로운 입력방식을 제안한다. 햅틱 피드백 디바이스인 ActivePen의 기능을 이용하여 보다 효율적인 멀티탭 방식의 키패드인 Stair-tap과 Time-tap을 소개하고 사용성 평가 결과를 보여준다.

• Structural Engineering and Mechanics
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• v.31 no.5
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• pp.621-624
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• 2009

The time delay in active and semi-active controls is an important research subject. Many researches on the time-delay control for deterministic systems have been made (Hu and Wang 2002, Yang et al. 1990, Abdel-Mooty and Roorda 1991, Pu 1998, Cai and Huang 2002), while the study on that for stochastic systems is very limited. The effects of the time delay on the control of nonlinear systems under Gaussian white noise excitations have been studied by Bilello et al. (2002). The controlled linear systems with deterministic and random time delay subjected to Gaussian white noise excitations have been treated by Grigoriu (1997). Recently, a stochastic averaging method for quasi-integrable Hamiltonian systems with time delay has been proposed (Liu and Zhu 2007). In the present paper, a stochastic optimal time-delay control method for stochastically excited nonlinear structural systems is proposed based on the stochastic averaging method for quasi Hamiltonian systems with time delay and the stochastic dynamical programming principle. An example of stochastically excited and controlled hysteretic column is given to illustrate the proposed control method.