• 대한전자공학회논문지
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• 제24권4호
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• pp.701-707
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• 1987

This paper is concerned with an accurate delay time modling of the ED MOS logic gates and its application to the multiple delay logic simulator. The proposed delay model of the ED MOS logic gate takes account of the effects of not only the loading conditions but also the slope of the input waveform. Defining delay as the time spent by the current imbalance of the active inverter to charge and discharge the output load, with respect to physical reference levels, rise and fall model delay times are obtained in an explicit formulation, using optimally weighted imbalance currents at the end points of the voltage transition. A logic simulator which uses multiple rise/fall delays based on the model as decribed in the above has been developed. The new delay model and timing verification method are evaluated with repect to delay accuracy and execution time.

• 한국가족관계학회지
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• 제22권3호
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• pp.131-153
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• 2017

Objective: This study aimed to examine the effects of adult children's marriage-delay on their parents' mental health. Furthermore, this study investigated how the influence of adult children's marriage-delay on parents' mental health could vary depending on the coresidence and employment status of the marriage-delayed adult children. Method: Two waves of Korean Longitudinal Study of Ageing (KLoSA) were used for the analyses. Multiple regression models were conducted with 2,938 Korean parents who had at least one child, regardless of gender (aged 33~44). Results: First, adult children's marriage-delay was related to lower levels of parents' life satisfaction. Second, the levels of parents' life satisfaction were low regardless of residing with their marriage-delayed adult children, and the parents who were not living with their marriage-delayed adult children showed lower levels of life satisfaction than parents living with marriage-delayed adult children. Third, only the parents with unemployed marriage-delayed adult children showed significantly higher levels of depression. However, the levels of parents' life satisfaction were low regardless of the employment of marriage-delayed adult children, and the parents of unemployed marriage-delayed adult children showed lower levels of life satisfaction than the parents of employed marriage-delayed adult children. Conclusions: It is necessary to consider the effects of marriage, employment and coresidence of adult children on their parents in order to enhance the mental health of the parents. Also, the effects of marriage-delay on intimate relationships, such as family dynamics, need to be explored more in further research.

• 한국정보과학회논문지:시스템및이론
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• 제29권6호
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• pp.354-360
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• 2002

지연시간 계산은 지연시간을 고려한 배치 단계에서 백만 번 이상도 수행되므로 효과적이면서 간단해야 한다. 본 논문에서는 계산은 매우 빠르고 간단하지만 수 백%의 오차를 가질 수 있는 Elmore delay를 개선하기 위해 Elmore delay와 SPICE 결과의 비율을 보상값으로 이용하는 방법을 제안한다. 제안한 새로운 방법은 resistance shielding effects를 고려하여 실험적으로 지연시간을 보상하여 그 오차를 크게 줄이며, 계산 복잡도는 Elmore delay와 같은 정도로 간단하다. Elmore delay가 31.6 ~ 145.2% 오차를 갖는 RC 트리에 대하여 실험한 결과, 보상된 delay의 오차는 2.5 ~ 22.7%로 크게 줄었다.

• 대한전기학회논문지
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• 제40권1호
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• pp.58-66
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• 1991

In inverters, time delays are inserted in the switching signals to prevent the dc lind shortage. This causes detrimental effects on the performance of the inverters, that is, the fundamental voltage drop and the generation of low order harmonics. This paper derives simple formula to describe the time delay effects in PWM inverters, where the effects may become significant because of relatively high switching frequencies. To compensate the tice delay effects, this paper presents two methods which are suitable for sinusoidal PWM and memory-based PWM respectively. Both are simple, easy to implement, and are shown to be effective, through the experiments, in improving the output waveform of PWM inverters.

• Structural Engineering and Mechanics
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• 제31권5호
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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.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1136-1141
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• 2004

This paper presents a control method for time-delay systems and verifies the performance of the designed control system via real experiments. Specifically, the control method is applied to a flexible-link system with time delays. The method combines time- and frequency-domain controllers: linear quadratic optimal controller (or LQR) and lag compensator. The LQR is used to stabilize the system in optimal fashion, whereas the lag compensator is used to compensate time-delay effects by increasing the delay margin of the system. With this methodology, the maximum allowable time delay can be increased significantly. The proposed method is simple but quite practical for time-delay system control as it is based on the conventional loop-shaping method, which gives practical insights on delay-phase relationship. Simulation and experiment results show that the method presented in this paper is feasible and practical.

• 제어로봇시스템학회논문지
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• 제7권11호
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• pp.953-957
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• 2001

This paper is concerned with a transfer alignment method for the SDINS under ship motions. Major error sources of transfer alignment are data transfer time-delay, lever-arm velocity and ship body flexure. Specifically, to reduce alignment errors induced by measurement time-delay effects, the error compensation method through delay state augmentation is suggested. A linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonliner measurement equation with respect to its time delay and augmenting the delay state into the conventional linear state equations. And then it is shown via observability analysis and computer simulations that the delay state can be estimated and compensated during ship motions resulting in considerably less alignment errors.

• 융복합기술연구소 논문집
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• 제5권2호
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• pp.37-42
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• 2015

This paper presents the effects of the computational time-varying delay on the stability of the haptic system that includes a virtual wall and a first-order-hold method. The model of a haptic system includes a haptic device model with a mass and a damper, a virtual wall model, a first-order-hold model and a computational time-varying delay model. In this paper, the maximum of the computational time-varying delay is assumed to be as much as the sampling time. Using the simulation, it is analyzed how the sample-hold methods and the computational time-varying delay affect the maximum available stiffness. As the maximum of computational time-varying delay increases, the maximal available stiffness of a virtual wall model is reduced.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.486-486
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• 2000

This paper is concerned with a transfer alignment method for the SDINS(StrapDown Inertial Navigation System) under ship motions. Major error sources of transfer alignment are data transfer time-delay, lever-arm velocity and ship body flexure. Specifically, to reduce alignment errors induced by measurement time-delay effects, the error compensation method through delay state augmentation is suggested. A linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonlinear measurement equation with respect to its time delay and augmenting the delay state into the conventional linear state equations. And then it is shown via observability analysis and computer simulations that the delay state can be estimated and compensated during ship motions resulting in considerably less alignment errors.

• 아동학회지
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• 제30권5호
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• pp.179-193
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• 2009

The purpose of this study was to examine relationships between preschoolers' temperament, mothers' parenting behaviors, and ability to delay gratification. A sample of 131 preschool children aged from 4 to 5 participated in a delay-of-gratification experiment, as reconstructed by Rodriguez and his colleagues (2005). Mothers answered questionnaires on their parenting behaviors and children's temperament. Data were analyzed by t-test, Pearson's correlation coefficients, and multiple regressions. Children's activity as well as mothers' warmth and control predicted the ability to delay gratification; significant interaction effects were found between children's activity and maternal warmth on the ability to delay gratification. It would be plausible to intervene in children's activity level and improve the ability to delay gratification.