• Title/Summary/Keyword: angular distance

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Classifying and analyzing galaxy pairs by their interacting features

  • Bang, Tae-Yang;Park, Myeong-Gu;Park, Changbom
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.2
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    • pp.64.2-64.2
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    • 2014
  • Interacting galaxy pairs are important for study of galaxy evolution. We selected 8,542 interacting galaxy pairs out of 593,514 KIAS-VAGC galaxy sample with 0.02 < z < 0.047 and r_mag <17.6. We then classified by their interacting features into 6 types by visual inspection. We focused on two types whose spiral tidal features extend to the center of early type galaxy (ETG) or to the edge of ETG. We compared galactic parameters of these two types with those of entire 8,542 pairs as well as between the two types. Preliminary result shows both types are very close pairs (projected distance ~ 20 kpc). Spiral galaxies in the center type are more massive but less bright than those in edge type. ETGs in the edge type are brighter but not more massive than those in the center type. The center type has a mass ratio 3.4 times greater than the edge type, but the edge type has a higher angular momentum than the center type.

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A ROENTGENOCEPHALOMETRIC STUDY ON THE CHILDREN OF NORMAL OCCLUSION IN THE MIXED DENTITION (혼합치열기 정상교합 아동에 관한 두부방사선 계측학적 연구)

  • Lee, Hee-Ju
    • The korean journal of orthodontics
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    • v.5 no.1
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    • pp.11-19
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    • 1975
  • This study was undertaken to investigate the exact values of the cephalometric standards of Hellman dental age III B groups of Korean in the reontgenocephalometry. The subjects consisted of 25 males and the same number of females with the normal occlusion and acceptable profile. Each lateral cephalometric head film was taken with the teeth in occlusion and the Focal-film distance was 300cm. Their linear and angular measurements were made directly. The following conclusions were obtained; 1) The author made the tables of standard deviation from the measured values. 2) The degree of the facial convexity of Korean children was larger than that of the white. 3) The labial inclination of the lower central incisor in male was a little greater than that in female.

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An analysis of the stars recorded in the Seong-Gyeong 星鏡

  • Jeon, Junhyeok
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.2
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    • pp.47.4-48
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    • 2017
  • In the middle of $19^{th}$ century, the Seong Gyeong 星鏡, which is a Korean historical astronomy book, was published by Nam Byeong-Gil(1820-1869). In this study, identification was conducted by considering the star catalogue recorded in the Yixiang Kaocheng Xubian 儀象考成續編. The Seong Gyeong 星鏡 recorded the information of 1,449 stars, and identified 1,413 stars among 1,449 stars, which is a rate of 97.5%. The positional error (angular distance) of the identified stars is $5.33{\pm}0.34$ arc-min. It was also confirmed that the magnitudes of the recorded stars have correlations with those of modern times. It was determined that the position error of the stars became larger as the magnitude of the stars became dimmer, or as the position of the stars came closer to the pole. Based on these analyses, the Seong Gyeong 星鏡 was confirmed that it is a result of correcting the precession of the selected stars from star catalogue of Yixiang Kaocheng Xubian 儀象考成續編.

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Control and data analysis of a measuring machine for cams (캠 형상 전용 측정기 제어 및 해석 S/W 개발)

  • 최동우;강재관
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.150-153
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    • 1997
  • In this paper, a control and data analysis S/W of a dedicated measuring machine for cams is developed. A rotary encoder is employed to measure the angular displacement of the motor, and a linear scale does the linear displacement of the prove. The design and measuring data are interpolated by cubic spline curves respectively to compute the error which is defined by the maximum distance between two curves. Further, optimization module to find the exact error is also developed to remove the error occurred due initial measuring position. The developed system takes only 6 minutes to measure the cam and to analyze the measuring data while the CMM takes about 1 hours even with a skilled operator.

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Bottom sediments of the Asan bay, west coast of Korea (아산만일대(牙山灣一帶) 해저퇴적물(海底堆積物)에 대(對)하여)

  • Kim, Sung-woo;Chang, Jeong-hae;Park, Yong-ahn
    • Economic and Environmental Geology
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    • v.11 no.2
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    • pp.81-88
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    • 1978
  • Nearly 300 bottom sediments and 20 box-cores were sampled from the Asan bay. The central portion of the Asan bay is covered by sand, slightly gravelly sand and gravelly muddy sand. Between the central and marginal zones gravelly mud and slightly gravelly sandy mud are characteristically distributed. The gravel population in the sediments seems to be originated from the rocky bottom on the area near the bay because the gravel is angular and composed of the schist and gneiss. The quartz/feldspar ratio is about 3/2. It is considered to be that the amount of feldspar in this bay is much higher than that of any other areas in the Yellow Sea. This is considerd to be comparatively short distance of transport ion of these sediment from the provenance.

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COMS METEOROLOGICAL IMAGER SPACE LOOK SIDE SELECTION ALGORITHM

  • Park, Bong-Kyu;Lee, Sang-Cherl;Yang, Koon-Ho
    • Proceedings of the KSRS Conference
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    • 2008.10a
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    • pp.100-103
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    • 2008
  • COMS(Communication, Ocean and Meteorological Satellite) has multiple payloads; Meteorological Image(MI), Ocean Color Imager(GOCI) and Ka-band communication payloads. MI has 4 IR and 1 visible channel. In order to improve the quality of IR image, two calibration sources are used; black body image and cold space look data. In case of COMS, the space look is performed at 10.4 degree away from the nadir in east/west direction. During space look, SUN or moon intrusions are strictly forbidden, because it would degrade the quality of collected IR channel calibration data. Therefore we shall pay attention to select space look side depending on SUN and moon location. This paper proposes and discusses a simple and complete space look side selection logic based on SUN and moon intrusion event file. Computer simulation has been performed to analyze the performance of the proposed algorithm in term of east/west angular distance between space look position and hazardous intrusion sources; SUN and moon.

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Developement of a System for Glass Thickness Measurement (비접촉 유리 두께 측정 장치 개발)

  • Park, Jae-Beom;Lee, Eung-Suk;Lee, Min-Ki;Lee, Jong-Gun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.5
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    • pp.529-535
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    • 2009
  • This paper describes a measuring device of glass thickness using machine vision and image processing techniques on real-time. Today, the machine vision enable to inspect fast and exactly than human's eyes. The presented system has advantages of continuous measurement, flexibility and good accuracy. The system consists of a laser diode, a CCD camera with PC. The camera located on the opposite side of the incident beam measures the distance between two reflected laser beams from the glass top and bottom surface. We apply a binary algorithm to convert and analyze the image from camera to PC. Laser point coordination by border tracing algorithm is used to find the center of beam circle. The measured result was compared with micrometer and showed 0.002mm accuracy. Finally, the errors were discussed how to minimize the influence of glass wedge angle and angular error of moving stage.

A Study on the Planning Characteristics of the Dosanseodang through the Review of "The Writings of Toegye" (퇴계집을 통하여 본 도산서당의 조영적 특성에 관한 연구)

  • 김영모;최기수
    • Journal of the Korean Institute of Landscape Architecture
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    • v.21 no.1
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    • pp.98-106
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    • 1993
  • As a faithful study about the intended plan of builder, this article studied the Dosanseodang(陶山書堂) which is located in the Dosanseodang(陶山書堂). The Dosanseowon is one of the representative Yi-Dynasty' Seowons. Through the review of $\ulcorner$The Writings of Toegye$\lrcorner$. It is found several intended plan of the Dosanseodang(陶山書 堂) as follows. 1. When Toegye located the site of the Dosanseodang in the Dosan, using four criteria such as 1) geographical characteristics(地 理), 2) hills and waters(山水) 3) form and orientation of valley, 4) so-cial characteristics. 2. In the Dosan area, the location of Seodang was determined by the physical characteristics of the valley(orientation and entrance), not by the concept of Fung-sui(風水). 3. The whole spatial structure of Seodang area formed triangle, and the Dosanseodang was located at the angular point of the triangle. 4. The landscape elements of the Dosanseodang falled into the three landscape hierarchy such as a front view, a middle view, and a distance view. Besides the three views, there was a borrowed view which Toegye defined in terms of ownership.

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Simulation of Axisymmetric Flows with Swirl in a Gas Turbine Combustor (Swirl이 있는 축대칭 연소기의 난류연소유동 해석)

  • Shin, Dong-Shin;Lim, Jong-Soo
    • Journal of the Korean Society of Combustion
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    • v.5 no.1
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    • pp.55-66
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    • 2000
  • A general purpose program for the analysis of flows in a gas turbine combustor is developed. The program uses non-staggered grids based on finite volume method and the cartesian velocities as primitive variables. A flow inside the C-type diffuser is simulated to check the boundary fitted coordinate. The velocity profiles at cross section agree well with experimental results. A turbulent diffusion flame behind a bluff body is simulated for the combustion simulation. Simulated results show good agreement with experimental data. Finally, a turbulent flow with swirl in a gas turbine combustor was simulated. The results show two recirculating region and simulated velocity fields agree well with experimental data. The distance between two recirculating regions becomes shorter as swirl angle increases. Swirl angle changes angular momentum and streamlines in flow fields.

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TIDAL EVOLUTION OF LUNAR ORBIT AND EARTH ROTATION

  • Na, Sung-Ho
    • Journal of The Korean Astronomical Society
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    • v.45 no.2
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    • pp.49-57
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    • 2012
  • In this study, I calculate the past and future dynamical states of the Earth-Moon system by using modified Lambeck's formulae. I find that the ocean tidal effect must have been smaller in the past compared to its present amount. Even though the Moon is already in the spin-orbit synchronous rotational state, my calculation suggest that it will not be in geostationary rotational state in the next billion years or so. This is due to the associated Earth's obliquity increase and slow retardation of Earth's spin and lunar orbital angular velocities. I also attempt to calculate the precessional period of the Earth in the future. To avoid uncertainties in the time scale, the future state is described by using the Earth-Moon distance ratio as independent parameter. Effects due to solar tidal dissipation are included in all calculations.