• 제어로봇시스템학회논문지
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• 제14권7호
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• pp.695-701
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• 2008

In this paper, we propose the efficient Doppler removal method using map-based partial-time common intermediate frequency removal technique. In the proposed algorithm, the 2-stage carrier removal process was used. First, the component of common intermediate frequency is removed. Next the component of Doppler was removed with averaging and approximation. For the evaluation of the proposed algorithm, The real-time software GPS L1 C/A-code receiver was implemented. When the proposed algorithms are used, 12 tracking channels with 3 track arm(early, prompt, late) is operated real-time on PC using a Intel Pentium-III 1.0GHz CPU. Also, the requirement of memory was less than 2Mbytes. The real-time software GNSS receiver using the proposed algorithms provides the navigation solution with below 10 meter rms error. Especially, in spited of using the various approximations for implementing the algorithms, the high sensitivity capability (able to track the weak signal with -159dBm) was achieved.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.1-10
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• 2018

Wide-area monitoring of tree-related high impedance fault (THIF) efficiently contributes to increase reliability of large-scaled network, since the failure to early location of them may results in critical lines tripping and consequently large blackouts. In the first place, this wide-area monitoring of THIF requires managing the placement of sensors across large power grid network according to THIF detection objective. For this purpose, current paper presents a framework in which sensors are distributed according to a predetermined risk map. The proposed risk map determines the possibility of THIF occurrence on every branch in a power network, based on electrical conductivity of trees and their positions to power lines which extracted from spectral data. The obtained possibility value can be considered as a weight coefficient assigned to each branch in sensor placement problem. The next step after sensors deployment is to on-line monitor based on moving data window. In this on-line process, the received data window is evaluated for obtaining a correlation between low frequency and high frequency components of signal. If obtained correlation follows a specified pattern, received signal is considered as a THIF. Thereafter, if several faulted section candidates are found by deployed sensors, the most likely location is chosen from the list of candidates based on predetermined THIF risk map.

• 한국환경복원기술학회지
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• 제25권2호
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• pp.85-92
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• 2022

The amphibian breeding habitat is confirmed by mating call. In some cases, the researcher directly identifies the amphibian individual, but in order to designate the habitat, it is necessary to map the mating call region of the amphibian population. Until now, it has been a popular methodology for researchers to hear mating calls and outline their breeding habitats. To improve this subjective methodology, we developed a technique for mapping mating call regions using Unmanned Aerial Vehicle (UAV). The technology uses a UAV, fitted with a sound recorder to record ground mating calls as it flies over an amphibian habitat. The core technology is to synchronize the recorded sound pressure with the flight log of the UAV and predict the sound pressure in a two-dimensional plane with probability density. For a demonstration study of this technology, artificial mating call was generated by a potable speaker on the ground and recorded by a UAV. Then, the recorded sound data was processed with an algorithm developed by us to map mating calls. As a result of the study, the correlation coefficient between the artificial mating call on the ground and the mating call map measured by the UAV was R=0.77. This correlation coefficient proves that our UAV recording system is sufficiently capable of detecting amphibian mating call regions.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제4권4호
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• pp.141-145
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• 2023

This study surveyed the changes in the proportion of Ecological and Natural Map (ENM) grades in Korea, the distribution ratio of ENM 1st-grade areas by region, and the current status of regional public appeals for the five-year period from 2017 to 2021. The nationwide changes in ENM grades revealed an increase in 1st-grade, 3rd-grade, and separately managed areas but a decrease in the ratio of 2nd-grade areas. Nationwide, Gangwon had the highest distribution ratio of 1st-grade areas, at 46.77%, while Gwangju had the lowest, at 0.05%. In the five-year study period, 383 appeals concerning ENM grades were received and processed. Gangwon had the greatest number of appeals, with 96, while Sejong had the fewest, with 1. A significant correlation was observed between the distribution ratio of 1st-grade areas and public appeals.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.735-739
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• 2005

This paper presents a new system to estimate the head pose of human in interactive indoor environment that has dynamic illumination change and large working space. The main idea of this system is to suggest a new morphological feature for estimating head angle from stereo disparity map. When a disparity map is obtained from stereo camera, the matching confidence value can be derived by measurements of correlation of the stereo images. Applying a threshold to the confidence value, we also obtain the specific morphology of the disparity map. Therefore, we can obtain the morphological shape of disparity map. Through the analysis of this morphological property, the head pose can be estimated. It is simple and fast algorithm in comparison with other algorithm which apply facial template, 2D, 3D models and optical flow method. Our system can automatically segment and estimate head pose in a wide range of head motion without manual initialization like other optical flow system. As the result of experiments, we obtained the reliable head orientation data under the real-time performance.

• 한국멀티미디어학회논문지
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• 제19권9호
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• pp.1647-1658
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• 2016

RGB+D database has been widely used in object recognition, object tracking, robot control, to name a few. While rapid advance of active depth sensing technologies allows for the widespread of indoor RGB+D databases, there are only few outdoor RGB+D databases largely due to an inherent limitation of active depth cameras. In this paper, we propose a novel method used to build outdoor RGB+D databases. Instead of using active depth cameras such as Kinect or LIDAR, we acquire a pair of stereo image using high-resolution stereo camera and then obtain a depth map by applying stereo matching algorithm. To deal with estimation errors that inevitably exist in the depth map obtained from stereo matching methods, we develop an approach that estimates confidence of depth maps based on unsupervised learning. Unlike existing confidence estimation approaches, we explicitly consider a spatial correlation that may exist in the confidence map. Specifically, we focus on refining confidence feature with the assumption that the confidence feature and resultant confidence map are smoothly-varying in spatial domain and are highly correlated to each other. Experimental result shows that the proposed method outperforms existing confidence measure based approaches in various benchmark dataset.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1993년도 추계학술대회
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• pp.163-166
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• 1993

It has been shown that some of physiological systems have nonlinear dynamics. The evidences of these nonlinear behaviors make us analyze physiological systems in the new viewpoint. And, nonlinear dynamics can be represented by chaotic behaviors, which is studied by several methods - correlation dimension, return map, power spectrum analysis, etc. This study is on the analysis of nonlinear characteristics of ECG. Data have been acquired from the 20 children (10 - 13 years old). and 30 students (20 -24 years old). We have calculated parameters HR, PR, VAT, TD, TRD from data. and estimated correlation dimension, return map, power spectrum. Results show the nonlinear characteristics of ECG.

• 한국측량학회지
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• 제29권2호
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• pp.141-147
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• 2011

본 연구는 최근 많이 촬영되고 있는 고해상도 디지털 항공영상자료를 가지고 제작된 대축척 수치지도를 이용하여 소축척 수치지도를 제작하는데 있어서의 문제점 및 효용성을 분석하였다. 이를 위하여 수치지도지형 지물들의 상관성 분석을 수행하였고, 이들 자료를 기초로 축소편집 작업 공정에 따라 자료를 입력, 지형 지물항목정리 및 삭제, 자료편집 및 검수 등을 수행하였다. 그 결과 18개의 불필요한 지형지물을 삭제하였고, 1/5,000 수치지도 정확도에 만족하였으며, 자료크기와 지형지물 수는 증가하였으나, 이는 디지털 항공영상의 표현능력이 우수하여 나타난 것으로 분석되었다. 따라서 디지털 항공영상에 의한 대축척 수치지도를 가지고 소축척 수치지도를 제작하는 것은 표현능력이 우수하여 질 좋은 수치지도 정보 제공이 가능한 것으로 나타났다.

• 천문학회보
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• 제22권
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• pp.35.2-35.2
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• 1997

• 대한원격탐사학회지
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• 제36권5_1호
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• pp.725-733
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• 2020

본 연구의 목적은 (1) MCD12Q1 자료를 이용하여 시계열 마스크 맵 작성하여 (2) 시계열 마스크 맵의 연차별 논벼 재배면적 변화를 추출하고, (3) MYD13Q1 NDVI와 단수와의 상관계수를 비교하여 (4) 적용성을 검토하는 것이다. 이를 위해 2002년부터 2019년까지의 연도별 MCD12Q1 PFT 자료를 수집하여 시계열 마스크 맵을 작성하고 고정형 마스크 맵과 비교하였다. 그 결과, 시계열 마스크 맵에 의한 논벼 재배면적이 실제 논벼 재배면적의 변동 특성을 잘 반영하고 있는 것으로 나타났으며, 고정형 마스크 맵과 비교하여 NDVI와 논벼 단수와의 상관계수도 높게 나타나 시계열 마스크 맵이 논벼 고유의 식생지수 추출 및 작황 모니터링, 단수 추정의 정확도를 높이는 방법임을 확인하였다.