• Aerospace Engineering and Technology
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• v.1 no.1
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• pp.28-41
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• 2002

The purpose of this paper is to show and define the performance, the system mechanization and the algorithm of the Strapdown Inertial Navigation System(SDINS). First, navigation equations are derived in the Earth Fixed mechanization and this mechanization apply to the two kinds of inertial measurement units which consist of same fiber optic gyros and different accelerometers(SDINS-1 and SDINS-2). Those two accelerometers have the different bias. To evaluate its performance, two kinds of tests have been performed - static motionless test, and rectangle-route moving test. The results of the moving test are compared with the results of Differential GPS which has an accuracy with ±2.0mm. and are presented in this paper.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.121-127
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• 2011

In the attitude and orbit control subsystem design, the moment of inertia of the satellite is the major contributor to be considered. Satellites equipped with large solar arrays need to measure the moment of inertia accurately to avoid the interference of the thruster actuation period with its flexible mode. In this paper, the in-orbit tests of COMS to measure the moment of inertia are described. Then, the differences between the measured through in-orbit test and the predicted are compared. Finally, it is verified that the differences are below uncertainty bounds considered in the critical design of COMS attitude and orbit control subsystem.

• Ceramist
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• v.22 no.2
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• pp.198-214
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• 2019

The possibility of economic exchange with North Korea is increasing, but there is still a shortage of information of cement industry, which occupies the largest proportion of North Korean construction material industry. Therefore, this study researched the status of cement production facility management using satellite photographs of 16 cement factories in North Korea, and examined the operating status of North Korean cement industry by observing smoke discharged from the chimneys of the cement production facilities. When the satellite photographs were analyzed, it was observed that the monthly stack fog ratio of the North Korean cement factories was 55% in 2016, 60% in 2017 and nearly 65% in 2018. This demonstrates that the average operating ratio has been increasing continuously. However, the operation rate of the five major cement factories reaches the limit, actual cement production is estimated to have maintained the previous level or small increased.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.16 no.1
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• pp.18-28
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• 2008

The purpose of this study is leading to prevent the major causes of commercial-aviation fatalities about controlled-flight-into-terrain(CFIT) in approach-and-landing accidents. The paper of major analysis for controlled flight into terrain(CFIT) was Guam accident, Mokpo accident and Gimhae accident in commercial transport-aircraft accidents from 1993 through 2002. CFIT occurs when an airworthy aircraft under the control of the flight crew is flown unintentionally into terrain, obstacles or water, usually with no prior awareness by the crew. This type of accident can occur during most phases of flight, but CFIT is more common during the approach-and-landing phase. Ninety-five percent of the Guam accident, Mokpo accident, and Gimhae accident where weather was known involved IMC, fog, and rain. The paper believed that prevention for CFIT accident was education and training for flying crew and upgrade for equipment such as EGPWS, and need more research for professional organizations of airlines, and accomplishing precision approaches should be a high priority.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.1
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• pp.21-29
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• 2003

The Strap Down Inertial Measurement Unit(SDIMU) is recently used for the sensor package of the modern underwater vehicles such as torpedoes and unmanned underwater-vehicles. For using SDIMU, an initial alignment must be carried out before the fire or navigation stage. The general initial alignment methods require that a mother vehicle Is a stationary condition or the Inertial Navigation System(INS) of vehicle is received the specific of data navigation from the mother vehicle. But an underwater vehicle dropped from aircraft is hard to satisfy above both necessary conditions of the general initial alignment. So, we suggest a new strap down initial alignment method of an underwater vehicle dropped from aircraft without using any aided sensors. The highlight point of this method is that a period of initial alignment is not before the fire but during running stage to fix alignment error. And we verify it by analyzing various data of S/W simulations, Hardware In the Loop Simulation(HILS) tests and sea trials.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.333-344
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• 1999

Currently many studies on the unmanned gantry crane for the automated container terminal are accomplished. This is needed for the development of large scale, automation, high speed, unmanned system and information system in port facility. In order to do efficient container handling job in port yard, the automated handling system is well adapted to the job environments and all-season weather, In order to realize the automatic and unmanned system for container handling job, the required functions and main structure system are studied. The major problems of operation of the conventional gantry crane are that the vibration of gantry structure body is occurred by operation and that high-speed and precision position-velocity control and the capability to dope to the external disturbances caused by the wind, rain, fog and job environments. In this paper, the fundamental study for establishment of the concept and the dynamic modelling of the major sub system of the unmanned gantry crane is presented. These studies are useful for design and manufacturing of the new concept model of the unmanned gantry crane for efficient operation of the automated container terminal.

• Annual Conference of KIPS
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• 2018.05a
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• pp.145-148
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• 2018

클라우드 컴퓨팅 기반 사물인터넷 환경은 급격히 증가하는 통신량, 기종 간 이질성, 지연 시간과 같은 문제점으로 인해 어려움을 겪고 있다. 이를 해결하기 위한 대표적인 방법 중 하나는 분산 모델을 통해 클라우드 컴퓨팅 환경에 집중된 네트워크 또는 컴퓨팅 파워를 분산시키는 포그 컴퓨팅 (Fog Computing) 또는 에지 컴퓨팅 (Edge Computing)을 활용하는 것이다. 그러나 이 분산형 네트워크의 단점을 보완하기 위해 사물인터넷 (IoT, Internet of Things)과 가장 가까이 존재하는 네트워크 모델로써 미스트 컴퓨팅 (Mist Computing)이 탄생하였다. 그러나 다양한 프로토콜에 의해 통신이 이루어지는 사물인터넷 환경에는 수천 가지 제로데이 공격이 존재한다. 이 공격들의 대부분은 이전에 알려진 공격의 작은 변형체이다. 이러한 공격을 효과적으로 막기 위해 사물인터넷 환경에서의 침입 탐지 시스템은 지능적이어야 한다. 따라서 본 논문에서는, 미스트 컴퓨팅 환경에서 새로운 또는 지속적으로 변화하는 사물인터넷 대상 공격을 효과적으로 방어하기 위한 인공지능 기반 침입 탐지 시스템을 제안한다.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.18 no.1
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• pp.6-18
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• 2011

Purpose: This study was done to explore the meaning and nature of life world for adolescents with epilepsy. The hermeneutic phenomenological method which was developed by van Manen was used. Methods: Participants were four boys and five girls, ages 13 to 18 being seen in a neurology outpatient department. Data were collected from iterative work with in-depth interviews from during the period from February to September, 2010. Contents of the interviews were tape-recorded with participant consent. Results: Essential themes that fit into the context of the 4 existential grounds of body, time, space and other people were: an illness that makes a hurt in one's heart rather than one's body, a change in the body that is not controllable, a future like thick fog, everyday life trapped in illness, a change of relationships, learning how to live with an illness. Conclusion: Findings reveal the life world of the adolescents is affected to varying degrees by the epilepsy. It is important for nurses to identify and address developmental issues and effects of the illness and to support reorientation in a disintegrated life situation. The result of this study will provide nurses with insights into these experiences and should help promote empathetic care.

• Korean Journal of Remote Sensing
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• v.24 no.1
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• pp.79-89
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• 2008

Irregular temporal sampling is a common feature of geophysical and biological time series in remote sensing. This study proposes an on-line system for reconstructing observation image series contaminated by noises resulted from mechanical problems or sensing environmental condition. There is also a high likelihood that during the data acquisition periods the target site corresponding to any given pixel may be covered by fog or cloud, thereby resulting in bad or missing observation. The surface parameters associated with the land are usually dependent on the climate, and many physical processes that are displayed in the image sensed from the land then exhibit temporal variation with seasonal periodicity. A feedback system proposed in this study reconstructs a sequence of images remotely sensed from the land surface having the physical processes with seasonal periodicity. The harmonic model is used to track seasonal variation through time, and a Gibbs random field (GRF) is used to represent the spatial dependency of digital image processes. The experimental results of this simulation study show the potentiality of the proposed system to reconstruct the image series observed by imperfect sensing technology from the environment which are frequently influenced by bad weather. This study provides fundamental information on the elements of the proposed system for right usage in application.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.70-70
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• 2017

영상처리 기법을 이용한 유속 측정 방법인 표면영상유속계는 비접촉식으로 간편하게 유속을 측정할 수 있다는 장점이 있지만 영상 내 추적자의 움직임을 식별하기 어려운 야간의 경우와 새벽의 안개가 발생하는 경우에 대한 유속 측정의 어려움이 있었다. 표면영상유속계를 이용한 야간 유속 측정은 조명과 적외선 카메라를 이용하여 수표면을 가시화하는 방법을 통해 현장 적용성을 검증하였으나, 안개 발생 상황에서는 적용하기 어렵다는 한계가 있었다. 야간과 안개 등의 한계를 동시에 극복하기 위한 방법으로 원적외선 카메라를 이용한 연구들이 이루어지고 있지만 아직 시작단계이고, 원적외선의 경우 주변 환경 변화에 따라 물체의 표면온도가 검출되는 파장이 달라져 영상의 품질에 차이가 발생하기 때문에 이에 대한 다양한 실험적 연구가 필요하다. 이에 본 연구에서는 야외 개수로에서 드라이아이스를 이용하여 안개 조건을 재현하고, 다양한 흐름 조건에서 원적외선 영상을 이용한 표면유속 측정 적용성을 검토하였다. 안개가 발생하는 경우 원적외선 표면영상 유속계를 적용한 결과 안개가 없을 때의 유속 측정 결과와 거의 일치하는 것을 확인하였다. 따라서 원적외선 카메라를 이용한 표면유속 측정 방법은 야간과 안개가 발생하는 상황에 모두 사용하기에 적합한 것을 나타났다. 향후 하천 유량조사에 원적외선 카메라를 활용한다면 기존의 표면영상유속계의 비가시 환경에 대한 한계들을 많은 부분 극복할 수 있을 것으로 기대한다.