• 제목/요약/키워드: Weak localization

검색결과 58건 처리시간 0.026초

스테레오 카메라 기반 모바일 로봇의 위치 추정 향상을 위한 특징맵 생성 (Generation of Feature Map for Improving Localization of Mobile Robot based on Stereo Camera)

  • 김은경;김성신
    • 한국정보전자통신기술학회논문지
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    • 제13권1호
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    • pp.58-63
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    • 2020
  • 본 논문은 스테레오 카메라를 이용한 모바일 로봇의 위치 추정 정확도 향상을 위한 방법을 제안한다. 스테레오 카메라로 획득한 스테레오 이미지로부터 위치 정보를 복원하기 위해서는 왼쪽 영상의 각 픽셀에 대응하는 대응점을 오른쪽 영상에서 찾아야 한다. 일반적으로 에피폴라 라인 위의 점들과 픽셀 유사도를 연산하여 대응점을 찾는 방법이 있다. 하지만 모든 에피폴라 라인 위의 점들을 다 탐색해야한다는 단점이 있고, 픽셀 값에 의해서만 유사도가 계산된다는 단점이 있다. 이를 보완하기 위해 본 논문에서는 좌/우 영상의 특징점을 추출 및 매칭하여 대응하는 점들이 같은 y축 상에 있을 경우, x좌표 값의 차를 구함으로 대응점 탐색방법을 간략하게 구현하였다. 또한 매칭이 되지 않아 소실되는 점들의 정보는 기존 알고리즘을 통해 대응점을 구함으로 특징점 수를 최대한 보존하고자 하였다. 특징점 및 대응점의 좌표를 통해 복원된 특징점의 3D 좌표를 기반으로 모바일 로봇의 위치를 보정하였다. 실험 결과, 제안하는 방법을 통해 좌표 보정을 위한 특징점 수를 증가시켰고, 특징점 추출만 수행한 경우보다 모바일 로봇의 위치도 보정 가능함을 확인하였다.

Immunohistochemical Localization of Endogenous IAA in Peach (Prunus persica L.) Fruit during Development

  • Zhang, Wei;Li, Yang;Shi, Mengya;Hu, Hao;Hua, Baoguang;Yang, Aizhen;Liu, Yueping
    • 원예과학기술지
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    • 제33권3호
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    • pp.317-325
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    • 2015
  • Peach (Prunus persica L.) is a model species for stone fruit studies within the Rosaceae family. Auxin plays an important role in the development of peach fruit. To reveal the distribution of auxin in the tissues of peach fruit, immunohistochemical localization of IAA was carried out in the seed, mesocarp, and endocarp in developing peach fruit using an anti-indole-3-acetic acid (anti-IAA) monoclonal antibody. A strong IAA signal was observed throughout the outer and inner integument during peach fruit development, and the distribution was zonal. The IAA signal was mainly focused in mucilage layers in the outer integument. The outer integument may function to produce or store IAA in the seed; a strong IAA signal was detected in the cells around the vascular tissue, whereas a weak IAA signal was located in the vascular tissues. In the mesocarp, the cells around the vascular bundle tissue gave rise to an IAA signal that increased in the late phase of fruit growth, which coincided with a significant increase in fruit growth. The distribution of IAA, however, was changed when fruit was treated with auxin transport inhibitors NPA (1-N-naphthylphthalamic acid) or TIBA (2, 3, 5-triiodobenzoic acid); in mesocarp tissues, an IAA signal was detected mainly in vessels of the treated fruit. During the critical period of endocarp lignification, the vessel lignification process was negatively correlated with IAA signal. The present results confirmed that the distribution of IAA was different in various tissues of peach fruit according to the developmental stage. This research provides cytological data for further study of the regulatory mechanism of auxin in peach fruit.

Microfabrics of omphacite and garnet in eclogite from the Lanterman Range, northern Victoria Land, Antarctica

  • Kim, Daeyeong;Kim, Taehwan;Lee, Jeongmin;Kim, Yoonsup;Kim, Hyeoncheol;Lee, Jong Ik
    • Geosciences Journal
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    • 제22권6호
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    • pp.939-953
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    • 2018
  • We examined the microfabrics of omphacite and garnet in foliated eclogite to determine the influence of the layered structure on seismic observations in subduction zone. The analyzed eclogite, from the Lanterman Range, northern Victoria Land, Antarctica, is characterized by layering in which the modal abundances of garnet and omphacite vary. For garnet, the low aspect ratios, similar angular distribution of long axes relative to the foliation in both layers, uniform grain size distribution, near-random crystallographic preferred orientations (CPOs), and misorientation angle distributions are indicative of passive behavior during deformation. In contrast, omphacite shows relatively high aspect ratios, a low angle between the long axes of crystals and the foliation, a wide grain-size distribution, and distinctive CPOs, suggesting dislocation creep as the main deformation mechanism. The results of fabric analyses are consistent with strain localization into omphacite or omphacite-rich layers rather than garnet or garnet-rich layers. The single-crystal seismic anisotropy of garnet is very weak ($AV_P=0.2%$, $AV_S=0.5-0.6%$), whereas that of omphacite is much stronger ($AV_P=3.7-5.9%$ and $AV_S=2.9-3.8%$). Seismic anisotropy of the omphacite-rich layers shows an increase of 329% for $AV_P$ and 146% for $AV_S$ relative to the garnet-rich layers. Our results demonstrate the importance of the layered structure in strain localization and in the development of the seismic anisotropies of subducting oceanic crust.

정합장 기반 표적 위치추정 시 모드공간 분석을 통한 간섭 신호 제거 기법 (Matched Field Source Localization and Interference Suppression Using Mode Space Estimation)

  • 김경섭;성우제;표상우
    • 한국음향학회지
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    • 제27권1호
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    • pp.40-46
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    • 2008
  • 천해 영역에서 선박과 같은 수상 소음원의 간섭 신호는 정합장처리를 이용한 수중 표적 탐지 및 위치추정 기법 적용에 있어 문제점으로 남아있다. 정지 음원의 경우 수신기공간의 음장에 대한 고유벡터분해를 통해 각 음원 성분을 분리하고 간섭 신호 성분을 제거할 수 있다. 하지만 일반적인 이동 음원 환경에서는 각 신호 성분의 에너지가 수신 음장의 부분공간에 퍼지게 되므로, 고유값 분포 비교만으로 각 신호 성분을 구별하기 어렵게 되거나 하나의 고유벡터에 각 신호성분이 섞이는 경우도 발생한다. 본 논문에서는 수상 음원과 수중 음원 신호의 물리적 특성 차이를 이용한 모드공간 간섭 신호 제거 기법을 제안하였다. 이 기법은 모드-공분산행렬에 대한 고유벡터분해를 통해 간섭 신호 성분을 판별하며, 이 성분들을 부분공간에서 제거함으로써 차폐되었던 표적 신호를 복원하고 위치추정을 가능하게 한다. 이를 모의실험을 통해 확인하고 결과에 대해 논의하였다.

기록관리 생태계의 선순환 구조에 관한 단상(斷想) (A Study on the Virtuous Cycle Structure of the Archival Ecosystem)

  • 김장환
    • 기록학연구
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    • 제79호
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    • pp.83-120
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    • 2024
  • 이 논문은 기록관리 생태계의 현황과 문제점 전반을 다루고 있다. 기록관리법 제정 이후 기록관리 생태계는 급속도로 성장했지만, 지금 시점에서 되돌아보면 기록학이라는 학문은 정체되어 있으며, 기록관리 실무 현장은 공공 영역에 과도하게 집중되어 있고, 민간 영역의 기록관리 인프라는 미약하며, 산업계는 고사하고 있다. 최근 몇 년간 기록 공동체는 이러한 문제점에 대하여 지속적으로 논의해왔으나, 대부분 공공기록관리 영역, 그중에서도 현장의 문제점에 집중되어 있음을 부정하기 어렵다. 이에 이 글에서는 기록학계와 대학의 문제점을 비롯하여 기록전문가의 전문성과 자격제도, 공공 영역에 국한된 기록관리법, 그리고 산업계의 어려움까지 기록공동체를 전체적으로 조망하고 그에 대한 대안을 전문성과 지역성의 측면에서 제안하였다.

발정주기(發情週期)에 따른 Guinea Pig의 자궁내막(子宮內膜) 기질세포(基質細胞)의 미세구조(微細構造)및 세포화학적(細胞化學的) 연구(硏究) (Ultrastructural and Cytochemical Studies on the Endometrial Stromal Cells of Guinea Pig during Estrous Cycle)

  • 등영건;유관희;최춘근;이춘구;정호삼
    • Applied Microscopy
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    • 제12권1호
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    • pp.57-68
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    • 1982
  • Cyclical changes in the fine structures of endometrial stroma of guinea pig during the estrous cycle were studied by electron microscopy. Cytochemical studies were made in order to investigate the ultrastructural localization of the acid phosphatase,alkaline phosphatase and ATPase in these cells. The results obtained are as follows: 1. During estrus collagen fibers were most abundant in the stroma. The stromal cells showed increases in the number of several cytoplasmic organelles, especially the rough endoplasmic reticulum was significantly increased and the structures were greatly differentiated. 2. Many cytoplasmic processes and cell debris have been distributed in the stroma of metestrus. The distributions were increased and degenerated mitochondria were observed during diestrus. 3. Cytochemical studies indicated that during metestrus and diestrus acid phosphatase activities were localized in the degenerating collagen fibers. Alkaline phosphatase activities were weak in the collegen fibers during proestrus and estrus which intense activities were localized around the cell membrane during metestrus and diestrus. ATPase activities were present on the cell membrane and intercellular space of stromal cell during proestrus and estrus.

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한국재래산양 혀에 분포하는 신경전달물질에 관한 면역조직화학적 연구 (Immunohistochemical studies on the distribution of neuropeptides in the tongue of Korean native goat)

  • 이흥식;이인세;강태천
    • 대한수의학회지
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    • 제36권2호
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    • pp.265-276
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    • 1996
  • This study was performed to identify the localization of several neuropeptides; calcitonin gene-related peptide(CGRP), substance P(SP), vasoactive intestinal polypeptide(VIP), neuropeptide Y(NPY), serotonin(5-HT) and neurotensin in the tongue of Korean native goat(Capra hircus) by immunohistochemical method. The results were summarized as follows: CGRP- and SP-immunoreactive fibers were observed as moderate immunoreactivity at the subepithelial plexus and subgemmal fibers in lamina propria of lingual papillae, but not seen in intragemmal, intergemmal, perigemmal fibers as well as in the supporting, basal and taste cells. Fibers around the acinus of the von Ebner's gland and blood vessels showed weak immunoreactivities against CGRP and SP. In the intrinsic ganglion cells, CGRP- and SP-immunoreactivities were not observed. The distribution patterns of VIP- and NPY-immunoreactive fibers were similar to CGRP-or SP-immunoreactive fibers, but their immunoreactivities were stronger than those of CGRP- or SP immunoreactive fibers. The immunoreactivities to VIP or NPY were seen in the intrinsic ganglion. Only a few serotonin immunoreactive fibers were seen in some filiform or fungiform papillae. Neurotensin immunoreactivity was not observed in the tongue of Korean native goat.

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Detection of Breathing Rates in Through-wall UWB Radar Utilizing JTFA

  • Liang, Xiaolin;Jiang, Yongling
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제13권11호
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    • pp.5527-5545
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    • 2019
  • Through-wall ultra-wide band (UWB) radar has been considered as one of the preferred and non-contact technologies for the targets detection owing to the better time resolution and stronger penetration. The high time resolution is a result of a larger of bandwidth of the employed UWB pulses from the radar system, which is a useful tool to separate multiple targets in complex environment. The article emphasised on human subject localization and detection. Human subject usually can be detected via extracting the weak respiratory signals of human subjects remotely. Meanwhile, the range between the detection object and radar is also acquired from the 2D range-frequency matrix. However, it is a challenging task to extract human respiratory signals owing to the low signal to clutter ratio. To improve the feasibility of human respiratory signals detection, a new method is developed via analysing the standard deviation based kurtosis of the collected pulses, which are modulated by human respiratory movements in slow time. The range between radar and the detection target is estimated using joint time-frequency analysis (JTFA) of the analysed characteristics, which provides a novel preliminary signature for life detection. The breathing rates are obtained using the proposed accumulation method in time and frequency domain, respectively. The proposed method is validated and proved numerically and experimentally.

왕복 스캔을 통한 수동형 RFID태그의 물리적 순차 추정기법 (A Physical Sequence Estimation Scheme for Passive RFID Tags using Round Trip Scan)

  • 이주호;권오흠;송하주
    • 한국멀티미디어학회논문지
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    • 제15권11호
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    • pp.1358-1368
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    • 2012
  • RFID (Radio Frequency Identification) 태그 순차 추정 기법은 RFID 리더의 움직임을 이용하여 선형적으로 배열된 수동형 태그들의 물리적인 순서를 추정하는 것이다. 수동형 태그와 리더는 전자기 유도에 의한 미세 전파를 이용하여 통신하므로 수동형 태그의 스캔(scan)은 불안정하게 이루어진다. 본 논문에서는 순차 추정의 정확도를 높이기 위해 리더의 왕복 스캔을 이용하였다. 제안 기법은 먼저 리더의 움직임이 바뀌는 반환점을 찾아낸다. 그리고 이동 방향별로 매 읽기 주기에 읽혀지는 태그들의 집합을 이용하여 태그 전체의 순차를 추정한다. 실험을 통해 제안하는 기법이 다양한 환경에서 순차추정의 정확도를 높일 수 있음을 보였다.

텅스텐 미세 전극을 이용한 전해 가공 (Electrochemical Machining Using Tungsten Microelectrode)

  • 류시형;유종선
    • 한국정밀공학회지
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    • 제26권4호
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    • pp.134-140
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    • 2009
  • The feasibility of electrochemical drilling and milling on stainless steel are investigated using tungsten microelectrode with $10{\mu}m$ in diameter. For the development of environmentally friendly and safe electrochemical process, citric acid solution is used as electrolyte. A few hundred nanoseconds duration pulses are applied between the microelectrode and work material for dissolution localization. Tool fracture by Joule heating, micro welding, capillary phenomenon, tool wandering by the generated bubbles are observed and their effects on micro ECM are discussed. Occasionally, complex textures including micro pitting corrosion marks appeared on the hole inner surface. Metal growth is also observed under the weak electric conditions and it hinders further dissolutions for workpiece penetration. By adjusting appropriate pulse and chemical conditions, micro holes of $37{\mu}m$ in diameter with $100{\mu}m$ in depth and 26Jim in diameter with $50{\mu}m$ in depth are drilled on stainless steel 304. Also, micro grooves with $18{\mu}m$ width and complex micro hand pattern are machined by electrochemical milling.