• 제어로봇시스템학회논문지
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• 제7권12호
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• pp.1024-1030
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• 2001

In this paper, a horizontal LOS(line of sight) rate estimator for conventional sea skimming ASM(anti-ship missile) is proposed. A LOS rate dynamics model for a 2-axis gimbal system and the homing geometry is derived. A new LOS rate estimator is proposed by applying the Kalman filter theory to the LOS rate dynamics model. The proposed filter estimates LOS rates by taking roll motions into account. Simulation results show that the proposed filter produces smaller estimation errors than a conventional method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.1932-1934
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• 2001

In this paper, a horizontal LOS(line of sight) rate estimator for conventional sea skimming ASM(anti-ship missile) is proposed. A LOS rate dynamics model in 2 axis gimbal system and in homing geometry is derived. And a new LOS rate estimator is proposed by applying a Kalman filter theory to the LOS rate dynamics model. The proposed filter can estimate LOS rates with taking roll motions into account. Simulation results show the proposed filter produces smaller estimation errors than a conventional method.

• Journal of Preventive Medicine and Public Health
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• 제29권1호
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• pp.51-65
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• 1996

The purpose of this study was to examine the trends of length of hospital stay (LOS), which is most likely to be a major attribute to hospital performance. From 1984 to 1994, an average LOS of each hospital was analyzed by factors such as medical departments, bed size, occupancy rate, region and ownership. This study was analyzed changing rate of LOS during 11 years. This rate was calculated by simple regression, which was used only with hospital without missing data during 11 years. This study findings are as follows. 1. The results indicated that the average LOS was steadily increased until 1990 but it was slightly decreased after 1990. 2. This trend could be found in all hospital scale and all group of occupancy rate. Specifically this trends of LOS were found in internal medicine, corporate owned hospitals, and hospitals in major city. But LOS of individual owned hospital was continuously increased until 1994. 3. Means of changing rates of LOS were calculated from 1984 to 1994. If we devided it into two parts, before 1990 and after 1990, most changing rates of LOS before 1990 except individual owned hospital were found positive sign. The changing rates after 1990 were negative sign but small hospital(lesser then 200 bed), individual owned hospital, national & public hospital and hospital in small urban have little change of LOS after 1990. Finally from this results we thought that most hospitals in Korea began to be concerned with LOS. Nevertheless LOS of several hospital such as small hospital or individual owned hospital was increased. And this trend may be caused by a few patients, low occupancy rate, or low profit. This trend of LOS is different from that of other countries. Perhaps this phenomenon is resulted from the reimbursement method. Because of fee for service reimbursement system in Korea the hospitals didn't need to shorten LOS in order to save the cost and increase the profit. Therefore reform of hospital cost reimbursement method will be needed to reduce hospital cost in Korea. We thought that the Korean health authority should consider the reimbursement method by unit of bundle of services, for example DRG and prepayment in the United States. This study presents some limitations such as no insight of severity of disease, case-mix measurement of hospital, and other clinical characteristics that can. possibly affect LOS. However, this study reports an important trend in LOS from 1984 to 1994.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.201-203
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• 2006

This paper describes a new LOS(Line-of-Sight) estimator for BTT missiles. The dynamic models of LOS rate and a seeker are derived. Based on these dynamic models, we design a nonlinear estimator, which takes into account roll motion of BTT missiles and sensor noises. Simulation results show that the LOS rate estimates of the proposed estimator are more accurate than those of the conventional estimator.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.268-273
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• 1991

Missile and target closing velocity is used in the proportional navigation(PN) missile guidance loop. But it is difficult to estimate the closing velocity when passive seeker is used and only the Line-of-Sight(LOS) rate is available in the guidance loop. In this study, new closing velocity estimation method is developed. This method uses LOS rate measurement only and uses some characteristics of PN guidance law. The Lyapunov method is used to analyze the stability of the developed estimation method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2082-2084
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• 2003

A practical real-time LOS rate estimator is proposed to handle the time-varying measurement noise statistics. To calculate the optimal Kalman gain, the algebraic transformation method is taken into account. By using the algebraic transformation, the differential algebraic Riccati equation(DARE) regarding estimation error covariance is replaced by the simple algebraic Riccati equation(ARE). The proposed LOS estimation filter gain is only a function of relative range. Consequently, the proposed method is computationally very efficient and suitable for embedded environment.

• 한국항공우주학회지
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• 제47권3호
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• pp.187-194
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• 2019

비축 적외선 탐색기는 공력 가열에 의한 열 차폐 효과를 완화시키기 위해 대공 고속 유도탄의 노즈콘 측면에 장착된다. 탐색기 출력은 표적을 지속적으로 추적하기 위한 유도탄의 롤 기동이 관여되었을 때 더 이상 시선각속도로 간주할 수 없다. 본 논문에서는 2축 김발 위에 장착된 비축탐색기를 위한 시선각속도 계산 방식을 제안한다. 첫째로, 실제 시선각속도 방정식은 해석적으로 도출되지만 조준각 오차 변화율을 측정할 수 없어 구현할 수 없다. 그에 따라 조준각 오차 변화율을 획득하기 위해 1차 지연 근사화를 제안한다. 제안한 시선각속도 계산 방식은 유도탄과 김발의 회전을 고려하여 커플링 효과를 보상할 수 있다. 제안한 방식의 성능을 비선형 6 자유도 시뮬레이션을 통해 검증하였다.

• 대한교통학회지
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• 제30권3호
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• pp.7-15
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• 2012

보행시설의 보행 LOS 산정시 한국도로용량편람의 방법론을 주로 사용하고 있는데, 지나치게 양호한 결과가 도출된다는 문제점이 지속적으로 지적되어 왔다. 이에 본 연구의 목적은 현재 널리 이용되고 있는 한국도로용량편람의 보행 LOS 분석방법에 대한 문제점을 파악하고, 서울시 사례를 이용하여, 다양한 보행시설 중 보도의 보행 LOS 분석방법에 대한 개선방안을 제시하는 것이다. 한국도로용량편람의 분석방법에 의해 서울시 보도의 보행 LOS를 진단한 결과, 전체 대상지점의 90%이상이 LOS A로 판정되어 지나치게 양호한 결과가 도출되었는데, 이의 개선방안으로 유효보도폭의 절대적 값을 고려하는 방안을 제시하였다. 그 결과 LOS C 및 LOS D에서 많은 변화가 나타나는 것을 알 수 있었다. 지금까지 보도를 대상으로 한 보행 LOS 진단 연구가 한정된 지역에 국한되어 진행되었다면 본 연구는 서울시 전역을 대상으로 하여 보도의 보행 LOS를 진단했다는 면에서도 의의가 있다고 할 수 있다.

• 대한토목학회논문집
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• 제29권3D호
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• pp.335-345
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• 2009

일반적으로 도로시설의 기본구간에 대한 서비스수준(LOS)의 효과척도로 밀도가 사용되지만, 도로시설의 현장에서 관측된 관측밀도와 교통특성자료로부터 산정된 산정밀도사이에는 오차가 발생할 수 있기 때문에 도로시설의 서비스수준을 제대로 나타낼 수가 없다. 따라서 본 연구의 목적은 연구대상 도시고속도로의 본선구간 상에 관측기기를 설치하여 실시간의 교통특성 자료(교통량, 속도, 점유율, 차두시간, 차두거리 등)를 수집 조사하고, 수집 조사된 교통특성자료의 상호관계로부터 연구대상 기본구간 상의 최대 교통류율을 비교 분석하며, 비교 분석된 최대 교통류율을 중심으로 각 서비스수준별 점유율과 v/c비율사이의 관계에 기초하여 도시고속도로의 기본구간에서 서비스수준의 평가기준을 산정 평가하고자 하는데 있다.

• Journal of Pharmaceutical Investigation
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• 제33권1호
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• pp.7-14
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• 2003

The PVP-based solid dispersion systems (SDs) containing lovastatin (LOS) and solubilizers (sodium lauryl sulfate, tween 80 and oleic acid) were prepared to enhance dissolution rate of practically water insoluble LOS using solvent evaporation method. Two different organic cosolvents either acetone/ethanol or acetonitrile/ethanol were used for the preparation of SDs. The LOS contents were highly decreased when acetone/ethanol cosolvents were used. The decrease of LOS contents was not caused by acetonitrile or acetone, based on HPLC data. The surface morphology as investigated by scanning electron microscope (SEM) and angle of repose as an index of flowability of SDs were highly dependent on the type and amount of solubilizers used. Based on differential scanning calorimetry (DSC) and X-ray powder diffraction data, the SDs made crystalline LOS into amorphous structure or partially eutectic mixtures. The simultaneous use of the solubilizers in SDs was also useful to increase dissolution rate of LOS in gastric or intestinal fluid. The SDs containing solubilizers reached 76% and 60% in gastric and intestinal fluid, respectively but the commercial tablet gave only less than 4%. These solubilizers in SDs could be also applicable for enhancing dissolution and bioavailability of poorly water-soluble drugs.