• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.352-361
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• 2021

An underwater positioning method that can be applied to structures for underwater construction is being developed at the Korea Institute of Ocean Science and Technology. The method uses an extended Kalman filter (EKF) based on an inertial navigation system for precise and continuous position estimation. The observation matrix was configured to be variable in order to apply asynchronous measured sensor data in the correction step of the EKF. A Doppler velocity logger (DVL) can acquire signals only when attached to the bottom of an underwater structure, and it is difficult to install and recover. Therefore, a complex sensor device for underwater structure attachment was developed without a DVL in consideration of an underwater construction environment, installation location, system operation convenience, etc.. Its performance was verified through a water tank test. The results are the measured underwater position using an ultra-short baseline, the estimated position using only a position vector, and the estimated position using position/velocity vectors. The results were compared and evaluated using the circular error probability (CEP). As a result, the CEP of the USBL alone was 0.02 m, the CEP of the position estimation with only the position vector corrected was 3.76 m, and the CEP of the position estimation with the position and velocity vectors corrected was 0.06 m. Through this research, it was confirmed that stable underwater positioning can be carried out using asynchronous sensors without a DVL.

• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.285-292
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• 2007

Magnetotelluric data recorded in the middle part of the Korean Peninsula are contaminated by severe noises at dead-band frequencies. In this study, we estimated the location of noise source using a source localization method. Since conventional beamforming techniques were not adequate for the localization of electromagnetic sources, we used the matched field processing and a genetic algorithm. The solutions for the strong noise signals tend to be localized in a narrow area, whereas those for natural MT signals shows randomly distributed patterns. The strong noise sources are mainly located in the western part of Kyonggi-do.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.316-317
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• 2018

어선원의 고령화와 1~2인 조업선의 증가로 인해 해상에서 추락 등의 인명사고의 위험성을 줄이기 위해 어선원의 조난위치 발신장치 사용에 필요한 사용자 편의성 향상을 위한 설문분석을 실시했다.

• Journal of the Korean Geotechnical Society
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• v.36 no.9
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• pp.45-55
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• 2020

X-ray computed tomography (CT) is very useful for the quantitative evaluation of internal structures, particularly defects in rock samples, such as pores and fractures. In situ CT allows 3D imaging of a sample subjected to various external treatments such as loading and therefore enables observation of changes that occur during the loading process. We reviewed state-of-the-art of in situ CT applications for geomaterials. Two triaxial cells made using relatively low density but high strength materials were developed aimed at in situ CT scanning during hydro-mechanical laboratory testing of rocks. Preliminary results for in situ CT imaging of granite and sandstone samples with diameters ranging from 25 mm to 50 mm show a resolution range of 34~105 ㎛ per pixel pitch, indicating the feasibility of in situ CT observations for internal structural changes in rocks at the micrometer scale. Potassium iodide solution was found to improve the image contrast, and can be used as an injection fluid for hydro-mechanical testing combined with in situ CT scanning.

• Proceedings of the Acoustical Society of Korea Conference
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• 1996.10a
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• pp.30-34
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• 1996

본 논문에서는 광대역 소음원의 위치를 탐지하여 2차원 영상면에 소음원을 영상화할수 있는 3차원 배열을 제안하였다. 배열 요소간의 상호상관함수가 2차원 영상면의 화소의 밝기에 대응되도록 영상함수를 유도하였으며 영상면은 사각면 및 원통면등으로 선택가능 하도록 하여 소음원의 위치동정 해석이 용이하도록 하였다. 몇가지 소음원에 대한 수치 모의실험결과는 제안된 배열이 소음원의 3차원적인 동정 해석 등에 응용될 수 있음을 보인다.

• The Journal of the Convergence on Culture Technology
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• v.3 no.2
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• pp.31-35
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• 2017

Recently, Many deliveries have sprung up and those are beginning to receive much attention from consumers. Like this, the application makes our lives more comfortable. Now, the delivery food application uses only static information of the user and the users only makes oder. In this thesis, however, the studies suggested that designed food application uses the user's location for mesuring a distance of delivery and estimated arrival time is displayed in the delivery application and The application provides a graphical view of the location of the user in real time.

• Journal of Oriental Neuropsychiatry
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• v.2 no.1
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• pp.19-28
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• 1991

내의원(內醫院)은 병원과 약국을 겸비한 일종의 궁중의료기관으로 의사를 비롯하여 여러의원들이 임금과 왕비 및 왕자들의 약을 조제하여 달이던 곳으로, 일명 내국(內局) 또는 약원(藥院)이라고 내의원 앞에 예시되어 있다. 그러나 내의원은 현재 그 내용이 전해지지 않고, 단지 관광지의 유물로만 여겨지고 있다. 현재의 내의원은 창덕궁(昌德宮)에 위치하고 있다. 내의원은 창덕궁의 돈화문(敦化門)을 지나, 인정전(仁政殿)을 거쳐 희정당(熙政當) 좌측에 있으며, 왕비의 거처인 대조전에 가장 가까이 자리잡고 있다. 내의원은 조선왕조 세종25년(1443)에 개원하게 되었으니, 이때는 정치, 문화적으로 안정이 이루어져 가는 상황이었다. 또한 당시 왕이나 왕비 기타 왕족들의 여러 가지 정신적인 갈등으로 인한 질병이 많았으며, 이로인해 전문적이고 독립적인 왕실의료기관의 필요성에 의해 내의원이 독립적인 개원이 이루어졌으리라 사료된다. 이로인하여 저자가 내의원에 관한 자료조사와 실제답사를 통하여 다음과 같은 사실을 알수 있었다. 1) 내의원의 개원은 조선왕조 초기 중앙의료질서 성립을 통한 봉건왕조의 절대왕권확립을 의미함으로 사료된다. 2) 내의원의 위치가 창덕궁의 중심부에 위치하고, 특히 어전(御殿)과 내전(內殿) 가까이에 위치함은 왕실의 질병을 신속하고도 중요하게 다루기 위함으로 사료된다. 3) 특히 의인을 내전에서도 대조전(大造殿) 가까히 둔것은 왕실의 질병중 왕비의 정신신체질환의 치료를 위함으로 사료된다. 4) 내의원의 진료형태는 왕진(往診)이었으며, 이는 당시 의원신분이 중인층이었음으로 사료된다. 5) 내의원의 이용중에서 평민에게는 왕명에 의해서만 이루어졌음으로 사료된다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.11
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• pp.884-890
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• 2018

In this paper, an improved method of estimating static source location is proposed based on the direct position determination(DPD) method, which estimates a source position directly using received signals. When the source position is estimated using the conventional DPD method, the estimation accuracy and error depend on a pair of receivers: a reference receiver and one of the multiple moving receivers. Based on this, the weighting values of the estimating source location were obtained using the covariance matrix for the pair of receivers($S_1$, $S_{2i}$) and applied to the DPD algorithm. Finally, the source position was estimated using the proposed DPD algorithm, and it was verified that the estimation accuracy improved, compared to the conventional DPD algorithm.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.1
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• pp.121-131
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• 2015

Passive emitter localization is preferred to use a small number of receivers as possible for the efficiency of strategic management in the field of modern electronic warfare support. Accurate emitter localization can be expected when utilizing continuous measurable parameters and a appropriate combination of theirs. For this reason, we compare CRLB (Cramer-Rao lower bound) of two moving platform with various measurable parameters to choose a appropriate combination of parameters for a better localization performance. And we propose the passive emitter localization method based on Levenberg-Marquardt algorithm with combined TDOA/FDOA and DOA to achieve better accuracy of emitter localization which is located on the ground and stationary. In addition, we present a method for determining the initial emitter position for LM algorithm's input to avoid the divergence of estimation and local minimum.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.23-28
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• 2019

A track type underwater construction robot(URI-R) which can trench on seabed is being developed by Korea Institute of Ocean Science & Technology. During the underwater trenching work, the robot is exposed high intensive noise and vibration so the underwater localization signal may not be obtained properly by the acoustic tracking system. Therefore it is necessary to research about continuous localization even though the measured position signal comes in intermittently. In this paper, the experiments were carried out on land to simulated the underwater operating environment characteristics. To estimate its position, inertial navigation system and global navigation satellite system are used. The effects of the period variation while localizing is investigated by the experiments, and the application for URI-R is proposed.