• Journal of Institute of Control, Robotics and Systems
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• v.7 no.12
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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.

• Proceedings of the KIEE Conference
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• 2001.07d
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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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• v.29 no.1 s.52
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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.

• Proceedings of the KIEE Conference
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• 2006.04a
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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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• 1991.10a
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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.

• Proceedings of the KIEE Conference
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• 2003.07d
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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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.3
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• pp.187-194
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• 2019

The off-axis Infra-Red(IR) seeker is mounted on the nose cone side of the anti-air high speed missile to alleviate thermal shield effect due to aerodynamic heating. The seeker output can not be regarded as the Line-of-Sight(LOS) rate any more as missile's roll motion to keep the target tracking is associated. In this paper, we propose a method to calculate the LOS rate for off-axis seeker on a 2-axis gimbal. Firstly, true LOS rate equations are analytically derived but not implementable because boresight error rate is not measurable. And then the first order lag approximation to obtain boresight error rate is proposed. The proposed LOS rate calculation method can compensate the coupling effect by considering the rotations of missile and gimbal. The performance of the proposed method is verified via full nonlinear 6-DOF(Degree of Freedom) simulations.

• Journal of Korean Society of Transportation
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• v.30 no.3
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• pp.7-15
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• 2012

Korean Highway Capacity Manual (KHCM) has been used when we analyze the pedestrian Level of Service (LOS) of a pedestrian facility. However, the pedestrian LOS by KHCM is largely insensitive to pedestrian congestion levels. The objective of this study is to identify the source of this problem within the KHCM calculation method, and to propose an improved method using the case study from Seoul. Based on KHCM results, the pedestrian LOS is A for more than 90% of the Seoul region, which seems to be unrealistic. On the other hand, this study includes an effective adjustment parameter using the absolute value of effective sidewalk width. Using this method, results shows some changes including newly identified areas of LOS C and LOS D. The analysis of pedestrian LOS is carried out for the entire metropolitan region of Seoul in order to evaluate area wide pedestrian level of service in Seoul.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3D
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• pp.335-345
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• 2009

Generally, density is used as a measure of effectiveness (MOE) of the level of service (LOS) for the basic segment of the roadway facility, but can not express the operational condition of the roadway facility properly because there can be an error in the computed density compared with the density measured in the field. Thus, the purpose of this study is to investigate the real-time traffic characteristic data (traffic flow, speed, occupancy, headway, spacing, etc.) from the detectors installed on the mainline section of urban freeway under the study, analyze the maximum flow rate from the relationship between the real-time traffic characteristics collected, and evaluate the LOS criteria within the basic segment of the urban freeway based on the relationship between the occupancy and the v/c ratio depending on the level of service.

• Journal of Pharmaceutical Investigation
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• v.33 no.1
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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.