• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제19권3호
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• pp.253-270
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• 2015

Two major simultaneous attack strategies have been introduced, as one of cooperative attack of multiple missiles. One strategy is an undesignated time attack, in which the missiles communicate among themselves to synchronize the arrival times by reducing the mutual differences of times-to-go of multiple missiles during the homing. The other is a designated time attack, in which a common impact time is commanded to all members in advance, and thereafter each missile tries to home on the target on time independently. For this individual homing, Impact-Time-Control Guidance (ITCG) law is required. After introducing cooperative proportional navigation (CPN) for the first strategy, this article presents a new closed-form ITCG guidance solution for the second strategy. It is based on the linear formulation, employing base trajectories driven by PNG with various navigation constants. Nonlinear simulation of several engagement situations demonstrates the performance and feasibility of the proposed ITCG law.

• Archives of Pharmacal Research
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• 제29권4호
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• pp.310-317
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• 2006

We investigated the effects of trinitrobenzene sulfonic acid (TNBS), an amino-group reagent, on the human ether-a-go-go-related gene (HERG) $K^+$ channels expressed in Xenopus oocytes. TNBS neutralizes the positively charged amino-groups of peptide N-terminal and lysine residues. External application of TNBS at 10 mM for 5 min irreversibly shifted the curves for currents at the end of the pulse and tail currents of HERG to a more negative potential and decreased the maximal amplitude of the $I_{tail}$ curve $(I_{tail,max})$. TNBS had little effect on either the activated current-voltage relationship or the reversal potential of HERG current, indicating that TNBS did not change ion selectivity properties. TNBS shifted the time constant curves of both activation and deactivation of the HERG current to a more hyperpolarized potential; TNBS's effect was greater on channel opening than channel closing. External $H^+$ is known to inhibit HERG current by shifting $V_{1/2}$ to the right and decreasing $I_{tail,max}$. TNBS enhanced the blockade of external $H^+$ by exaggerating the effect of $H^+$ on $I_{tail,max}$, not on $V_{1/2}$. Our data provide evidence for the presence of essential amino-groups that are associated with the normal functioning of the HERG channel and evidence that these groups modify the blocking effect of external $H^+$ on the current.

• 한국지구과학회지
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• 제23권2호
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• pp.188-193
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• 2002

Various research methods have been used in science depending on the various contexts. This implies that certain methods or inferences may be more frequently used in earth science. The purpose of the study are to explore the contexts of earth science, and the inferences frequently used in earth science. The context earth science research is quite different from that of other areas of natural science in terms of its time scale, space scale, accessibility, complexity, and controllability. The purpose of earth science research is twofold: historical and causal. The inferences frequently used in earth science are abduction and prediction. Abductive inferences go from the resulting state to controlling state. Predictive inferences go from hypothesis to expected data.

• Journal of Mechanical Science and Technology
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• 제15권4호
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• pp.433-440
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• 2001

A new design of the sliding mode control is proposed for the uncertain linear time-varying second order system. The proposed control drives system states to the target point in the minimum time with specified ranges of parametric uncertainties and disturbances. One of the advantages of the proposed control scheme is that the control inputs do not go beyond saturation limits of the actuators. The other advantage is that the minimum arrival time and the acceleration of the second order actuators system can be estimated with given parametric bounds and can be expressed in the closed from; conversely, the designer can select actuators based on the condition of the minimum arrival time to the target point. The superior performance of the proposed control scheme to other sliding mode controllers is validated by computer simulations.

• 가정과삶의질연구
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• 제3권1호
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• pp.15-22
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• 1985

This study was designed to examine leisure time and leisure activities of homemakers and to predict future leisure time and future leisure time orientation. Present leisure time and future leisure time orientation were studied in relation to sociodemographic and physical environmental variables, time use variables and attitude variables. The major findings were the average daily housework time of homemakers was 6.5 hours on weekends. Housework time of employed homemakers was 3.5 hours and full-time homemakers was 8.0 hours. Daily leisure time of homemakers was 4.0 hours on weekdays and 4.8 hours o weekends. Most homemakers leisure activities on weekdays and weekends were reading, watching TV or listening to the radio and resting. In the future, they want to go hiking, hunting, traveling or fishing, attending concerts, drama or movies and playing sports games. The homemakers who felt their amount of present leisure time was sufficient were 35.4% and insufficient were 37.9%. Regarding the present leisure activities, 43.1% of homemakers expressed dissatisfaction, though 21.9% of them satisfied. Factors affecting the homemakers weekday leisure time were homemakers' occupation, family type, type of heating form house and cooking, weekday and weekend housework time of homemakers. Weekend leisure time interacted with family life cycle, number of children, income, education and occupation of homemakers, size of house, type of heating for house and cooking, weekday housework time of homemakers. housework time of employed housekeeper, husbands' weekend housework time, weekday leisure time of homemakers.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1826-1834
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• 2011

The traffic realizes that people come and go. The mobility is on the basis of location and time. The physical means for the traffic is composed of roads, vehicles and fuel. The current traffic services place emphasis on the physical elements. In the near future, with the current elements, the railroad service is considerably improved of through intangible factors including the customized customer services that the mobile-social network service is newly applied. The intangible things are connected to the increase of the time value for customers.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.68-69
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• 2011

Realistic amounts of time delay are found to have significant effects on the average output LED current and on the critical inductor value at the boundary between the two conduction modes. Especially, the time delay can provide an accurate LED current for the peak current controlled (PCC) buck converter with a wide input voltage. Experimental results are presented for the PCC buck LED driver with constant-frequency controller.

• 동력기계공학회지
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• 제6권3호
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• pp.64-70
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• 2002

A fast decoupled algorithm for time domain simulation of power electronics circuits is presented. The circuits can be arbitrarily configured and can incorporate feedback amplifier circuits. This simulation algorithm is performed for the input series output parallel connected 2 switch forward converter. Steady state and large signal transient responses due to a step load change are simulated. The simulation results are verified through experiments.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.533-537
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• 2002

A fast time domain modeling and simulation is performed for the input-series-output-parallel connected 2-switch forward converter Steady-state and large-signal transient responses due to a step load change are simulated. The simulation results are verified through experiments.

• 인지과학
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• 제29권4호
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• pp.265-281
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• 2018

본 연구는 현재와 미래의 긍정성과 부정성이 특정 미래 시점까지 시간적 거리 판단에 미치는 영향과 시간표현에 미치는 영향을 경험적으로 검증해보고자 하였다. 실험 1에서는 현재와 미래를 긍정적이거나 부정적인 상황으로 조작하고 참가자들에게 미래 시점까지의 시간적 거리감을 판단하도록 요구하였다. 그 결과, 현재와 미래가 모두 긍정적인 경우이거나 현재는 긍정적이지만 미래가 부정적인 경우에 미래 시점까지의 시간적 거리를 가깝게 추정하였다. 반면에, 현재와 미래가 모두 부정적이거나 현재는 부정적이지만 미래가 긍정적인 경우에는 미래 시점까지의 시간적 거리를 먼 것으로 판단하였다. 아울러 시간적 거리 판단은 미래의 상황보다 현재의 상황이 더 큰 영향을 미친다는 것을 확인할 수 있었다. 실험 2에서는 실험 1과 동일한 상황을 참가자들에게 제시하여 주관적 시간에 대한 느낌을 표현해볼 것을 요청하였고 그 결과를 토대로 주관적 시간표현을 인지적 측면과 정서적 측면으로 분류하였다. 실험 2의 결과를 근거로 하여 특정 미래 시점을 빠르거나 가깝게 느끼는 주관적 시간을 '가용의 시간'이라는 용어로, 특정 미래 시점을 느리거나 멀게 느끼는 주관적 시간을 '감내의 시간'이라는 용어로 명명하였다.