• 한국신뢰성학회지:신뢰성응용연구
• /
• 제18권1호
• /
• pp.1-7
• /
• 2018

Purpose: Maintaining appropriate operational availability (Ao) is a key element of combat victory, but estimates vary according to estimation methods. The purpose of this study is to improve the accuracy of estimating operational availability by tracing the changes of the weapon system's failure rate, repair rate, and the level of logistic support. Methods: In order to track the change in the operating availability, the MDT (mean down time) is modeled by adding the repair time and the ALDT (administration and logistic delay time) to the service time. Results: Using the field data of the weapon system A operated by the ROKAF, the failure rate follows a non-homogeneous Poisson process that changes with time, and it is modeled considering the changing repair rate and the logistic support time. Conclusion: The accuracy of the analytical results was verified by comparing the actual operating data with the estimated availability. The results of this study can be used to track and evaluate the availability in a realistic situation where the failure rate and maintenance rate continuously change in operating environment.

• 상하수도학회지
• /
• 제14권1호
• /
• pp.45-53
• /
• 2000

The optimum operation of domestic wastewater treatment plant can give influence on operational cost and future expansion in Korea where has 93 operational domestic wastewater treatment plants. Also, the study on optimum operation can reduce operation cost and budget of municipalities whom have responsibility of wastewater treatment plant operation. In this study, 9 domestic wastewater treatment plants which can represent 93 plants in Korea have been selected and operational data are gathered. The collected data are inputted to computer simulator based on IAWQ's Activated Sludge Model No.1 and optimum operation methods are developed. Also, the electric power for aeration which has large portion of overall operation cost are calculated based on design and operation conditions and these are compared. In this study, it was found that design wastewater characteristics are 1.6 times higher than those of daily maximum except for E plant and that estimation methods for design wastewater characteristics have to be improved. Based on computer simulation, we found there is no need to operate all aeration tanks due to weak influent overall power for aeration can be reduced to about 43% of design one.

• 한국항행학회논문지
• /
• 제12권6호
• /
• pp.681-690
• /
• 2008

소프트웨어를 개발하여 발행하기 전에 품질을 향상시키는 중요한 방법으로서 신뢰도를 향상 시켜야 하며, 이의 직접적인 방법으로서는 테스트를 통하여 결함을 검출하고 수정해가는 것이다. 신뢰도가 목표치에 도달하면 이를 발행(release)하게 되며, 그 후로는 운영중의 신뢰도 문제가 발생하게 된다. 개발 발행된 소프트웨어가 패키지 소프트웨어라 불리는 범용 소프트웨어냐, 아니면 특수목적을 가진 전용 소프트웨어냐에 따라 운영 소프트웨어의 신뢰도 추이가 달라진다. 또한, 개발 테스트 단계의 테스트 노력이 일정하냐, 아니면 웨이불 곡선을 따르냐에 따라서도 신뢰도 평가가 다르다. 본 논문에서는 주문형 소프트웨어에 대해서 일정 테스트 노력을 적용하는 경우와 웨이불 테스트 노력을 적용하는 경우의 운영단계 신뢰도 추이에 대해서 고찰 하였으며 웨이불 테스트 노력을 적용한 경우의 운영 기간 중의 신뢰도 저하가 되는 결과를 얻었다.

• 한국군사과학기술학회지
• /
• 제21권3호
• /
• pp.403-412
• /
• 2018

In this study, a three-dimensional variational(3DVAR) data assimilation system was developed for the operational numerical weather prediction(NWP) system at the Republic of Korea Air Force Weather Group. The Air Force NWP system utilizes the Weather Research and Forecasting(WRF) meso-scale regional model to provide weather information for the military service. Thus, the data assimilation system was developed based on the WRF model. Experiments were conducted to identify the nested model domain to assimilate observations and the period appropriate in estimating the background error covariance(BEC) in 3DVAR. The assimilation of observations in domain 2 is beneficial to improve 24-h forecasts in domain 3. The 24-h forecast performance does not change much depending on the estimation period of the BEC in 3DVAR. The results of this study provide a basis to establish the operational data assimilation system for the Republic of Korea Air Force Weather Group.

• 산업경영시스템학회지
• /
• 제42권2호
• /
• pp.9-17
• /
• 2019

In order to deal with high uncertainty and variability in emergency medical centers, many researchers have developed various models for their operational planning and scheduling. However, most of the models just provide static plans without any risk measures as their results, and thus the users often lose the opportunity to analyze how much risk the patients have, whether the plan is still implementable or how the plan should be changed when an unexpected event happens. In this study, we construct a simulation model combined with a risk-based planning and scheduling module designed by Simio LLC. In addition to static schedules, it provides possibility of treatment delay for each patient as a risk measure, and updates the schedule to avoid the risk when it is needed. By using the simulation model, the users can experiment various scenarios in operations quickly, and also can make a decision not based on their past experience or intuition but based on scientific estimation of risks even in urgent situations. An example of such an operational decision making process is demonstrated for a real mid-size emergency medical center located in Seoul, Republic of Korea. The model is designed for temporal short-term planning especially, but it can be expanded for long-term planning also with some appropriate adjustments.

• 제어로봇시스템학회논문지
• /
• 제2권4호
• /
• pp.330-336
• /
• 1996

An real-time active beacon localization system for mobile robots is developed and implemented. This system permits the estimation of robot positions when detecting light sources by PSD(Position Sensitive Detector) sensor which are placed sparsely over the robots work space as beacons(or landmarks). An LSE(Least Square Estimation) method is introduced to calibrate the internal parameters of a model for the beacon and robot position. The proposed system has two operational modes of position estimation. One is the initial position calculation by the detection of two or more light sources positions of which are known. The other is the continuous position compensation that calculates the position and heading of the robot using the IEKF(Iterated Extended Kalman Filter) applied to the beacon and dead-reckoning data. Practical experiments show that the estimated position obtained by this system is precise enough to be useful for the navigation of robots.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
• /
• pp.916-919
• /
• 1996

An real-time active beacon localization system for mobile robots is developed and implemented. This system permits the estimation of robot positions when detecting light sources by PSD(Position Sensitive Detector) sensor which are placed sparsely over the robot's work space as beacons(or landmarks). An LSE(Least Square Estimation) method is introduced to calibrate the internal parameters of a model for the beacon and robot position. The proposed system has two operational modes of position estimation. One is the initial position calculation by the detection of two or more light sources positions of which are known. The other is the continuous position compensation that calculates the position and heading of the robot using the IEKF(Iterated Extended Kalman Filter) applied to the beacon and dead-reckoning data. Practical experiments show that the estimated position obtained by this system is precise enough to be useful for the navigation of robots.

• 한국정보관리학회:학술대회논문집
• /
• 한국정보관리학회 1994년도 제1회 학술대회 논문집
• /
• pp.19-22
• /
• 1994

the Term Dependence Models has been examined in vew of the theoretical aspects. For the feasibility of these models in an operational system, the parameter estimation problem and other alternative solution has been included.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.503-504
• /
• 2014

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2012년도 추계학술대회 논문집
• /
• pp.482-483
• /
• 2012