• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.27-29
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• 2018

승객대피분석은 승객이 안전한 최종 탈출지점까지 대피하는데 걸리는 시간을 산출 하는 것과 다수의 승객이 하나의 대피경로로 몰리면서 정체현상이 일어나는지를 판단하는 것이 중요하다. 본 논문에서는 무선측위 정보를 활용하여 데크별 선내인원정보를 확인하고 이를 바탕으로 안전한 탈출지점까지 모든 승객이 대피하는데 걸리는 시간이 실시간으로 산출 가능한 기술을 승객안전 대피지원 시스템에 적용하였고 선박의 운용중 발생 가능한 사고 대응시 초기대응에 도움을 주고 위기사항이나 승무원의 훈련에도 활용 가능하도록 제시하고자 한다.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.3
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• pp.366-374
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• 1999

본 논문에서는 사용자가 세계 주요도시 및 국가의 표준시각 서비스를 보다 손쉽게 이용하고 안내 음성 시간의 증대로 인한 서비스 사용시간의 증가를 최소한으로 줄이기 위하여 ARS 시스템의 절차를 간소화하였다. 그리고 사용자가 보다 빠른 시간 안에 편리하게 세계 주요 국가 및 도시의 표준시각 서비스를 제공하기 위한 방안으로서, 세계 주요도시 표준시각 안내를 위한 국내 시보 및 세계 시보 서비스로의 접근 시나리오 및 해당 안내 멘트를 개발하였다. 또한, 116 세계시보 서비스를 위한 망 구성 및 시스템의 구성요소들을 제시하고 , 통계처리 및 운용자 관리 등을 위한 화면을 구성하여 116 세계 시보 서비스시스템을 구현하였으며 시보에 대한 신뢰성을 평가하기 위하여 개발한 시보 장치의 표준시에 대한 시각차를 분석하여 시각의 정확성을 검증하였다.

• Annual Conference of KIPS
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• 2014.11a
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• pp.152-155
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• 2014

현대전에서 C4ISR 및 PGM 능력 보유가 점점 중요해지는 만큼 무기체계 위협에 대응시간 또한 점차 짧은 시간을 요구하고 있다. 미 해군에서는 제1, 2차 세계대전을 통해 대공위협에 대한 협동 대응 필요성 자각이후 협동교전능력(CEC : Cooperative Engagement Capability)를 발전시켜왔지만 한국군에서는 아직 개념이 미개발되어 있는 상태이다. CEC의 여러 능력 성분 중에서 한국해군 수상전투단에서 가장 필요로 하는 요소가 가장 짧은 대응시간을 요구하는 대함유도탄 협동대응능력일 것이다. 이를 구현하기 위해 전투단내 함정 간 정보를 교환할 수 있는 통신프레임을 디자인하여 제시하고 실제 운용 가능성을 예측한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.6
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• pp.740-747
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• 2012

An Active Electronically Scanned Array(AESA) radar required necessarily as the Fire Control Radar(FCR) of recent fighters has ununiform detection range with regard to scan angle due to scan loss. Although the compensation method of scan loss in an AESA radar with variable dwell time is investigated, the effectiveness of the method in a fighter FCR with multi-function such as search, track, and missile guidance within limited resources should be considered systematically. In this paper, uniform search performance of an AESA radar using variable dwell time with regard to scan angle is derived. We assumed the search load of 50 % for case without changing dwell time in fixed frame time and showed the fighter FCR requirement for multi-function is not satisfied because the search load for the uniform search performance should be increased by about 100 %. On the other hand, in case of increasing the frame time for the uniform search performance and search load of 50 %, degradation of the search performance is shown by 86.7 % compared with the former. Based on these analyses, the effective beam operation strategy on an airborne AESA radar with uniform search performance in whole scan area is described with consideration of frame time, search load and performance as a whole.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.251-257
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• 2021

An underwater platform operating a passive sonar needs to acquire the target position to perform its mission. In an environment where sea-floor reflections exist, the position of a target can be estimated using the difference in the arrival time between the signals received through multipaths. In this paper, a method of localization for passive sonar is introduced, based on the EKF (Extended Kalman Filter) using the multipath time difference of arrival in underwater environments. TMA (Target Motion Analysis) requires accumulated measurements for long periods and has limitations on own-ship movement, allowing it to be used only in certain situations. The proposed method uses an EKF, which takes measurements of the time differences of the signal arrival in multipath environments. The method allows for target localization without restrictions on own-ship movement or the need for an observation time. To analyze the performance of the proposed method, simulation according to the distance and depth of the target was performed repeatedly, and the localization error according to the distance and water depth were analyzed. In addition, the correlation with the estimated position error was assessed by analyzing the arrival time difference according to the water depth.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.448-454
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• 2020

This study aims to determine the cause of structural defects occurring during aircraft operations and to verify the structural integrity of the improved features. The fracture plane was analyzed to verify the characteristics of the cracks and the fatigue failure leading to the final fracture was determined by the progress of the cracks by the repeated load. During aircraft operations, the comparative analysis of the load measurement data at the cracks with the aircraft design load determined that the measured load was not at the level of 30% of the design to be capable of being damaged. A gap analysis resulted in a significant stress of approximately 32 ksi at the crack site. Pre-Load testing also confirmed that the M.S. was reduced by more than 50% from +0.71 to +0.43, resulting in a sharp increase in aircraft load and the possibility of cracking when combined. Thus, structural reinforcement and the removal of the gap for aircraft cracking sites improved the defect. Based on the structural strength analysis of the improvement features, the bulkhead has a margin of about +0.88 and the fitting feature is about +0.48 versus allowable stress. In addition, the life analysis results revealed an improvement of approximately 84000 hours.

• Journal of Aerospace System Engineering
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• v.14 no.1
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• pp.68-73
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• 2020

This purpose of this paper was to review the development trend of the VTOL MAVs with a ducted propellant that can fly like the VTOL at intermediate and high speeds, hovering, landing, and lifting off vertically over urban areas, warships, bridges, and mountainous terrains. The MAV differs in flight characteristics from helicopters and fixed wings in many respects. In addition to enhancing thrust, the duct protects personnel from accidental contact with the spinning rotor. The purpose of the U.S. Army FCS and DARPA's OAV program is spurring development of a the VTOL ducted MAV. Today's MAVs are equipped with video/infrared cameras to hover-and-stare at enemies hidden behind forests and hills for approximately one hour surveillance and reconnaissance. Class-I is a VTOL ducted MAV developed in size and weight that individual soldiers can store in their backpacks. Class-II is the development of an organic VTOL ducted fan MAV with twice the operating time and a wider range of flight than Class-I. MAVs will need to develop to perch-and-stare technology for lengthy operation on the current hover-and-stare. The near future OAV's concept is to expand its mission capability and efficiency with a joint operation that automatically lifts-off, lands, refuels, and recharges on the vehicle's landing pad while the manned-unmanned ground vehicle is in operation. A ducted MAV needs the development of highly accurate relative position technology using low cost and small GPS for automatic lift-off and landing on the landing pad. There is also a need to develop a common command and control architecture that enables the cooperative operation of organisms between a VTOL ducted MAV and a manned-unmanned ground vehicle.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.969-972
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• 2015

Many studies have been carried out in order to develop a frequency efficient communication system than the current communication system for satisfying the increasing demands of wireless data services in mobile communication systems. If a communication system dramatically improving the frequency utilization efficiency is not developed, service providers must maintain more number of base station equipments to meet the increasing demands of wireless data service. Service provider needs a system or method to reduce maintenance costs. Demands of wireless data service are changed according to time of day, location and so on. Power consumption can be reduced if the supplied power of communication systems is controlled by wireless data traffics. This paper describes the design and implementation of power management system of mobile communication base station's equipment based on smart grid. The proposed power management system controls the supplied power to the mobile communication infrastructures depending on the demand of wireless data. Field test results of the implemented system show the proposed system saves 26% of the power consumption in the base stations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.428-434
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• 2020

The one-shot weapon system is destroyed after only one mission. So, the system requires high reliability. Guided missiles are one-shot weapon systems that have to be analyzed by storage reliability since they spend most of their life in storage. The analysis results depend on the model and the ratio of correct censored data. This study was conducted to propose a method to more accurately predict the future failure rate of Air force guided missiles. In the proposed method, the failure rate is predicted by both MTTF (Mean Time To Failure) and MTBF (Mean Time Between Failure) models and the model with a smaller error from the real failure rate is selected. Next, with the selected model, the ratio of correct censored data is selected to minimize the error between the predicted failure rate and the real failure rate. Based on real field data, the comparative result is determined and the result shows that the proposed sampling rate can predict the future failure rate more accurately.

• Journal of the military operations research society of Korea
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• v.36 no.2
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• pp.11-24
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• 2010

Quick precision-strike capability of the artillery will be an important factor in modern and future war and it's represented by NCW and EBO. This study is based on artillery which has time limitation of firing, such as artillery which hides when not firing, and modeling various situations to decide firing order and who to shoot. The main purpose of this study is to suggest a mathematical programming model and a genetic algorithm which satisfies the limitation of firing time. The objective function is to minimize the total firing time to spend. The results of the suggested algorithm quickly gives a best solution for a large scale field artillery targeting problems.