• 한국보건간호학회지
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• 제23권2호
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• pp.207-218
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• 2009

Purpose: In an attempt to develop a parental health improvement education program for day care children, survey questions were devised to measured the extent of parental health knowledge, health-guidance execution and needs. Method: Participants were 727 parents whose children attended daycare centers in J province informed consent was provided prior to participation. Result: Respondents were overwhelmingly (91.6%) mothers. Questions with high percentage of incorrect answers were "What should I do if my child swallows harmful drugs, bleach or detergents?" (98.1%) and "What should I do if insects or other bugs enter my child's ear?" (96.6%). In most cases, parental health-guidance execution exceeded 90% except in response to the survey question "Does your child have a dental check-up every 6 months" (51%). Taken together, parental education is necessary concerning growth and development (12.8%), nutrition (12.1%), healthy life styles (10.3%) and general health issues (10.0%). Conclusions: Parental health knowledge about preschooler's health varies with degree of income, education and type of employment. Consideration of these variables is important in a parental health education program.

• 한국군사과학기술학회지
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• 제1권1호
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• pp.211-218
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• 1998

As a part of trajectory modulation to increase system survivability and terminal effectiveness, impact angle control is required in the terminal phase of tactical missile systems. The missile systems are not allowed to have high altitude to reduce probability of detection by sensors of missile defense systems. In this paper, an analytic form of a time-optimal control law is suggested in the case of constrained missile maneuverability and impact angle under the assumption of a zero-lag autopilot. The control law is obtained by establishing optimal missile-target engagement geometry in the vertical plane. Extension of the law for missiles with autopilot response lags requiring a numerical solution is studied by introducing an iterative algorithm for optimal switching time determination of which the initial switching instants are obtained from the analytic solution. Also suggested is a closed-form impact angle control law derived by an energy-optimal approach. The performances of the proposed guidance laws are evaluated by a series of computer runs.

• Nuclear Engineering and Technology
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• 제46권2호
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• pp.273-280
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• 2014

The spectrum weighted responses of various detectors were calculated to provide guidance on the proper selection and use of survey instruments on the basis of their energy response characteristics on the neutron fields. To yield the spectrum weighted response, the detector response functions of 17 neutron-measuring devices were numerically folded with each of the produced calibration neutron spectra through the in-house developed software 'K-SWR'. The detectors' response functions were taken from the IAEA Technical Reports Series No. 403 (TRS-403). The reference neutron fields of 21 kinds with 2 spectra groups with different proportions of thermal and fast neutrons have been produced using neutrons from the $^{241}Am$-Be sources held in a graphite pile, a bare $^{241}Am$-Be source, and a DT neutron generator. Fluence-average energy ($E_{ave}$) varied from 3.8 MeV to 16.9 MeV, and the ambient-dose-equivalent rate [$H^*(10)/h$] varied from 0.99 to 16.5 mSv/h.

• 대한교통학회지
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• 제30권1호
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• pp.85-101
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• 2012

주차안내정보시스템은 심각한 주차문제들을 해결하고 주차시설 확충의 제약을 해결하기 위한 방법으로 도입되었다. 이미 선진국들은 주차안내정보시스템을 도입하여, 효율적인 주차 운영 관리를 하고 있다. 그러나 우리나라는 선진국에 비해 관련 연구 및 기술 개발이 미미한 실정이며, 이에 따라 시스템 구축사례 또한 매우 적은 실정이다. 본 연구는 이러한 주차안내정보시스템의 확대 보급을 활성화시키기 위해 기존 시스템 구축 상의 단점을 분석하고 이를 보완하기 위해, 발전되고 있는 USN 기술을 적용한 시스템을 개발하였다. 또한, 현장 테스트를 수행하여 시스템을 검증하기 위해 실제 도로에 Test-Bed를 설치하였다. 그리고 시범운영 중 데이터 수집 분석을 수행하였다. 알고리즘 개발을 위해 기존의 선행연구 및 관련 이론들을 고찰하였으며, 이 예측알고리즘은 시스템에 적용하였다. 이 결과, 기존 주차안내정보시스템의 문제점인 물리적인 제약 및 네트워크 구성의 복잡성을 극복하여 구축 편의 및 비용절감을 도모하였으며, 시스템의 제공 오차는 최대 3% 이내로 나타나 연구의 활용성 및 유용성을 확보하였다.

• 한국항공우주학회지
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• 제38권3호
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• pp.264-273
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• 2010

본 연구에서는 무인항공기의 편대비행을 위해서 먼저 단일 무인항공기의 기본적인 자세제어, 고도제어를 포함하는 유도제어시스템을 설계 제작하여 검증하고, 이 시스템을 바탕으로 먼저 선도기의 위치 정보를 이용하여 선도기와 추종기간의 앞뒤거리와 좌우 거리를 피드백하여 비례미분제어한 결과를 보여준다. 보다 안정적이고 성능이 우수한 편대 비행을 위하여 선도기의 위치와 자세 정보를 이용하여 추종기가 따라가야할 가상경로점을 실시간으로 계산하고 이를 바탕으로하여 추종기가 따라가도록 유도 명령을 생성하여 비행제어를 하고, 또한 선도기의 롤명령정보를 추종기의 최종 유도명령에 추가하여 편대 비행 성능을 향상시킬 수 있음을 보여준다. 이러한 과정은 여러 가지 경우에 대한 비행시험 결과를 분석하여 알고리즘을 점차 개선하는 방식을 취했으며 다소 실험적인 방식으로 최종 편대비행 알고리즘을 확립하였다. 최종적으로 채택한 기법을 이용하여 3대의 무인항 공기를 자동비행 상태에서 편대 비행을 수행한 결과를 보여준다.

• 소음진동
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• 제6권1호
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• pp.27-34
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• 1996

In this paper, design sensitivity of vibration displacement and acceleration is computed and design sensitivity, the derivative information of responses with respect to design perameters, is used as a design guidance tool to reduce the vibration. First, the harmonic vibration analysis of deck and simplified ship structures is performed by finite element method and secondly continuum disign sensityivity for excessive dynamic response is computed by continuum method. Both the direct and modal frequency response methods for the finite element analysis are adopted. Sensitivities of structural components such as upper plate, side wall, bilge, bottom plate are compared and the reductionof vibration is obtained by the proper increase of thickness of each component.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1266-1271
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• 2007

General coil spring has linearity. However, disc spring has non-linearity so that using this non-linearity disc spring can be designed to do shock-absorbing in cases we need because shock response also has non-linearity. By changing the shape and stacking number, it is satisfactory with response of displacement, velocity and acceleration. Conventionally, disc spring was used to control the vibration against huge load and limited space. However, it is limitedly used because of difficulty of the designing guidance. Therefore, disc spring is needed to study further in order to apply it widely. Response of disc spring is compared to response of coil spring by changing ho/t radio with computer simulation and the usage of disc spring is increased through analysis of effect of design factors. The purpose of this paper is that the shock response of disc spring is calculated through numerical simulation and effect of ho/t and stiffness is analyzed to broad usage so that design factor of disc spring is presented.

• 한국소음진동공학회논문집
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• 제18권2호
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• pp.153-159
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• 2008

General coil spring has linearity. However, disc spring has non-linearity so that using this non-linearity disc spring can be designed to do shock-absorbing in cases we need because shock response also has non-linearity. By changing the shape and stacking number, it is satisfactory with response of displacement, velocity and acceleration. Conventionally, disc spring was used to control the vibration against huge load and limited space. However, it is limitedly used because of difficulty of the designing guidance. Therefore, disc spring is needed to study further in order to apply it widely. Response of disc spring is compared to response of coil spring by changing $h_o/t$ ratio with computer simulation and the usage of disc spring is increased through analysis of effect of design factors. The purpose of this paper is that the shock response of disc spring is calculated through numerical simulation and effect of $h_o/t$ and stiffness is analyzed to broad usage so that design factor of disc spring is presented.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.845-849
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• 1992

The disturbance and time delay can often cause a significant error in the estimation of trajectory of a underwater vehicle. The time delay considered in this study is due to the delayed rudder response to the rudder input from the guidance control part. The simulation tests are performed on maneuver with constant rudder angle, zigzag maneuver, dive-climb maneuver, and corridor pattern maneuver. The results are compared with those of without delay cases.

• International Journal of Control, Automation, and Systems
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• 제1권1호
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• pp.76-82
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• 2003

This paper establishes some integral equalities formulated by zeros located in the convergence region of a Laplace transformable function. Using the definition of the Laplace transform, it shows that Laplace transformable functions have to satisfy the integral equalities in the time-domain, which can be applied to the understanding of the fundamental limitations on the control system represented by the transfer function. In the unity-feedback control scheme, another integral equality is derived on the output response of the system with open-loop poles located in the convergence region of the output function. From these integral equalities, two sufficient conditions related to undershoot and overshoot phenomena in the step response, respectively, are investigated.