• Title/Summary/Keyword: 초기 정렬

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An Improved Convex Hull Algorithm Considering Sort in Plane Point Set (평면 점집합에서 정렬을 고려한 개선된 컨벡스 헐 알고리즘)

  • Park, Byeong-Ju;Lee, Jae-Heung
    • Journal of IKEEE
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    • v.17 no.1
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    • pp.29-35
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    • 2013
  • In this paper, we suggest an improved Convex Hull algorithm considering sort in plane point set. This algorithm has low computational complexity since processing data are reduced by characteristic of extreme points. Also it obtains a complete convex set with just one processing using an convex vertex discrimination criterion. Initially it requires sorting of point set. However we can't quickly sort because of its heavy operations. This problem was solved by replacing value and index. We measure the execution time of algorithms by generating a random set of points. The results of the experiment show that it is about 2 times faster than the existing algorithm.

Performance Analysis on the Initial Alignment of Laser Inertial Navigation System (레이저 관성항법장치 초기정렬 성능 분석)

  • Kim, Hyun-Seok;Kim, Cheon-Joong;Lee, Tae-Gyoo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.5
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    • pp.622-635
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    • 2009
  • Laser Inertial Navigation System(LINS) consists of Ring Laser Gyroscopes(RLG) and accelerometers. RLG has a lock-in region in which there is zero output for input angular rates less than about 0.1deg/sec. The lock-in region is generated by the imperfect mirrors in RLG. To avoid the lock-in region, a sinusoidal motion called dither motion is applied on RLG. Therefore this dither motion is measured by RLG/accelerometer even if at a stop state. In this situation, the performance on the initial alignment of LINS can be degraded. In this paper, we analyze the performance on the initial alignment of LINS theoretically and experimentally. Analysis results include how dither motion, the pre-filter and the corner frequency in alignment loop affects the performance on the initial alignment of LINS.

Performance Analysis in Disturbance on Initial Alignment of Laser Inertial Navigation System Using Unscented Kalman Filter (UKF를 적용한 레이저 관성항법장치의 외란에 대한 초기정렬 성능분석)

  • Oh, Juhyun
    • Journal of the Korea Institute of Military Science and Technology
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    • v.17 no.4
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    • pp.537-543
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    • 2014
  • RLG(Ring Laser Gyroscope) is a main device of LINS(Laser Inertial Navigation System). RLG has the lock-in region in which there is no output signal. To alleviate the lock-in problem, a mechanical oscillation, the dither motion, is applied on RLG. A LPF(Low Pass Filter) is usually used on the output of RLG and accelerometer to remove the noise that is made by the dither motion. When the LINS is induced the disturbance during the initial alignment, it takes more time on alignment due to the use of the LPF and a fixed gain controller. In this paper, an initial alignment using UKF(Unscented Kalman Filter) is designed and analysed. Analysis include comparison between conventional initial alignment loop using fixed gain type controller and proposed initial alignment using UKF. Moreover, Disturbance inducing test results are demonstrated.

An Analysis of the Attitude Estimation Errors Caused by the Deflection of Vertical in the Initial Alignment (초기정렬에서 수직편향으로 인한 자세 추정 오차 분석)

  • Kim, Hyun-seok;Park, Chan-sik
    • Journal of Advanced Navigation Technology
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    • v.26 no.4
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    • pp.235-243
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    • 2022
  • In this paper, in the case of an inertial navigation system, the posture estimation error in the initial alignment due to vertical deflection is analyzed. Posture estimation error due to DOV was theoretically analyzed based on the speed and posture error of INS. Simulations were performed to verify the theoretical grinding, and the results were in good agreement. For example, in the case of η=20", an alignment error of ϕN=0.00287°, ϕU=0.00196° occurred, and in the case of 𝜉=20", an error of ϕE= -0.00286° occurred. Through this, it was confirmed that the vertical posture error caused by the DOV occurred as a coupling characteristic of the INS posture error. It has been shown that an additional posture error may occur due to the DOV, which was not considered in the existing INS alignment, which means that correction for the DOV must be considered when applying high-precision INS.

Shrink-Wrapped Boundary Face Algorithm for Surface Reconstruction from Unorganized 3D Points (경계면 축소포장에 기반 한 비정렬 3차원 측정 점으로부터의 표면 재구성)

  • 박은진;최영규;이재협;구본기;추창우;김재철
    • Proceedings of the Korean Information Science Society Conference
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    • 2004.10b
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    • pp.628-630
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    • 2004
  • 정렬되지 않은 3차원 측정 점들로부터 이들을 근사하는 표면을 재구성하는 방법을 제안하였다. 제안된 방법은 경계면 축소포장 방식에 의한 표면 재구성 방법 (shrink-wrapped boundary face : SWBF)으로, 측정 점으로부터 경계셀과 경계면을 구해 초기 메쉬를 생성하고 이를 연속적으로 축소하는 방식에 의해 표면을 재구성한다 제안된 방법은 기존의 표면 축소포장 방식의 메쉬 생성 방법의 문제점인 물체의 토폴로지에 대한 제악이 없이 어떠한 형태의 표면 재구성에도 적용이 가능하며, 기존 방법이 축소 단계에서 각 메쉬 정점에 대한 최단거리 측정점을 찾는 전역 탐색을 해야 하는데 비해 지역 탐색만으로 최적의 측정 점을 찾을 수 있으므로 처리 시간 측면에서도 우월하다. 실험을 통해 제안된 표면 재구성 알고리즘이 측정 점들간의 관계를 알 수 없는 정렬되지 않은 3차원 정들에 대한 표면 재구성에 매우 안정적이고 효과적임을 확인할 수 있었다.

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On Constructing NURBS Surface Model from Scattered and Unorganized 3-D Range Data (정렬되지 않은 3차원 거리 데이터로부터의 NURBS 곡면 모델 생성 기법)

  • Park, In-Kyu;Yun, Il-Dong;Lee, Sang-Uk
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.37 no.3
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    • pp.17-30
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    • 2000
  • In this paper, we propose an efficient algorithm to produce 3-D surface model from a set of range data, based on NURBS (Non-Uniform Rational B-Splines) surface fitting technique. It is assumed that the range data is initially unorganized and scattered 3-D points, while their connectivity is also unknown. The proposed algorithm consists of three steps: initial model approximation, hierarchical representation, and construction of the NURBS patch network. The mitral model is approximated by polyhedral and triangular model using K-means clustering technique Then, the initial model is represented by hierarchically decomposed tree structure. Based on this, $G^1$ continuous NURBS patch network is constructed efficiently. The computational complexity as well as the modeling error is much reduced by means of hierarchical decomposition and precise approximation of the NURBS control mesh Experimental results show that the initial model as well as the NURBS patch network are constructed automatically, while the modeling error is observed to be negligible.

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A Study of An Initial Alignment Method of Underwater Vehicle Dropped from Aircraft (항공기에서 투하되는 수중운동체의 초기정렬기법 연구)

  • 류동기;김삼수
    • 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.

Growth and Energy Level Alignment of Pentacene on SiO2 Surfaces before and after OTS Treatment (OTS처리 전후 실리콘산화막 위에서 펜타신의 성장과 에너지준위의 정렬)

  • Kim, J.W.;Lee, Y.M.;Park, Y.
    • Journal of the Korean Vacuum Society
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    • v.17 no.5
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    • pp.394-399
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    • 2008
  • Growth and electronic structure of pentacene film on silicon oxide before and after octadecyltrichlorosilane (OTS) treatment have been studied by photoelectron spectroscopy and photoelectron emission microscopy. On the OTS-treated surface, due to the weak interaction between the substrate and pentacene, the diffusion of pentacene is enhanced and domain size gradually grows, leading to a gradual change of the HOMO offset position. On the bare silicon oxide, the change of the HOMO position is marginal because of relatively strong interaction between the substrate and pentacene from the beginning.

Ferrimagnetic Resonance Studies of Poly-crystalline $Mn_x$ Ferrites (Mn-Zn 훼라이트의 자기공명 특성연구)

  • 김정렬;박명희;박윤창
    • Journal of the Korean Magnetics Society
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    • v.2 no.2
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    • pp.105-113
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    • 1992
  • 조성이 Mn$_{x}$Zn$_{1-x}$ Fe$_{2}$O$_{4}$ 훼라이트(x=0.75, 0.52)를 pusher type 연속 전기로를 이용하여 질소 분위기하에서 1360 .deg. C 로 3시간 동안 소결하여 얻어냈다. 본 연구에서는 스피넬 구조인 Mn-Zn 훼라이트의 FMR(Ferrimagnetic Resonance) 스펙트럼 특징과 초기투자율과의 상관성을 조사하고자 EPR X-band 스펙 트로미터를 이용 9.50 GHz의 microwave frequency에서 FMR 실험을 수행하였다. FMR 공명흡수선은 주 자기공명 흡 수선외에 낮은 자기장에서 약한 subsidiary 공명흡수선을 나타내는데 온도변화에 따른 주 자기공명 흡수선과 sub- sidiary 공명흡수선(제2, 제3 공명흡수선)의 세기, 공명선폭, g값 등의 온도 의존성을 연구함으로써 제2 공명흡수 선이 나타나는 원인을 분석하였으며, 자기공명 흡수선의 g값, 자기공명선 세기, 그리고 공명선폭과 초기투자율의 상관성을 연구하였다. 실험 결과 주 자기공명 흡수선의 g값, 자기공명선 세기, 공명선폭은 초기투자율 값과 밀접 한 관련이 있음을 확인할 수 있었다.었다.

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