• 제목/요약/키워드: space and time scale

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Astronomical Instruments with Two Scales Drawn on Their Common Circumference of Rings in the Joseon Dynasty

  • Mihn, Byeong-Hee;Choi, Goeun;Lee, Yong Sam
    • Journal of Astronomy and Space Sciences
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    • 제34권1호
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    • pp.45-54
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    • 2017
  • This study examines the scale unique instruments used for astronomical observation during the Joseon dynasty. The Small Simplified Armillary Sphere (小簡儀, So-ganui) and the Sun-and-Stars Time-Determining Instrument (日星定時儀, Ilseong-jeongsi-ui) are minimized astronomical instruments, which can be characterized, respectively, as an observational instrument and a clock, and were influenced by the Simplified Armilla (簡儀, Jianyi) of the Yuan dynasty. These two instruments were equipped with several rings, and the rings of one were similar both in size and in scale to those of the other. Using the classic method of drawing the scale on the circumference of a ring, we analyze the scales of the Small Simplified Armillary Sphere and the Sun-and-Stars Time-Determining Instrument. Like the scale feature of the Simplified Armilla, we find that these two instruments selected the specific circumference which can be drawn by two kinds of scales. If Joseon's astronomical instruments is applied by the dual scale drawing on one circumference, we suggest that 3.14 was used as the ratio of the circumference of circle, not 3 like China, when the ring's size was calculated in that time. From the size of Hundred-interval disk of the extant Simplified Sundial in Korea, we make a conclusion that the three rings' diameter of the Sun-and-Stars Time-Determining Instrument described in the Sejiong Sillok (世宗實錄, Veritable Records of the King Sejong) refers to that of the middle circle of every ring, not the outer circle. As analyzing the degree of 28 lunar lodges (lunar mansions) in the equator written by Chiljeongsan-naepyeon (七政算內篇, the Inner Volume of Calculation of the Motions of the Seven Celestial Determinants), we also obtain the result that the scale of the Celestial-circumference-degree in the Small Simplified Armillary Sphere was made with a scale error about 0.1 du in root mean square (RMS).

Vertical Scale Height of the Topside Ionosphere Around the Korean Peninsula: Estimates from Ionosondes and the Swarm Constellation

  • Park, Jaeheung;Kwak, Young-Sil;Mun, Jun-Chul;Min, Kyoung-Wook
    • Journal of Astronomy and Space Sciences
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    • 제32권4호
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    • pp.311-315
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    • 2015
  • In this study, we estimated the topside scale height of plasma density (Hm) using the Swarm constellation and ionosondes in Korea. The Hm above Korean Peninsula is generally around 50 km. Statistical distributions of the topside scale height exhibited a complex dependence upon local time and season. The results were in general agreement with those of Tulasi Ram et al. (2009), who used the same method to calculate the topside scale height in a mid-latitude region. On the contrary, our results did not fully coincide with those obtained by Liu et al. (2007), who used electron density profiles from Arecibo Incoherent Scatter Radar (ISR) between 1966 and 2002. The disagreement may result from the limitations in our approximation method and data coverage used for estimations, as well as the inherent dependence of Hm on Geographic LONgitude (GLON).

개선된 스케일 스페이스 필터링과 함수연결연상 신경망을 이용한 화학공정 감시 (Monitoring of Chemical Processes Using Modified Scale Space Filtering and Functional-Link-Associative Neural Network)

  • 최중환;김윤식;장태석;윤인섭
    • 제어로봇시스템학회논문지
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    • 제6권12호
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    • pp.1113-1119
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    • 2000
  • To operate a process plant safely and economically, process monitoring is very important. Process monitoring is the task to identify the state of the system from sensor data. Process monitoring includes data acquisition, regulatory control, data reconciliation, fault detection, etc. This research focuses on the data recon-ciliation using scale-space filtering and fault detection using functional-link associative neural networks. Scale-space filtering is a multi-resolution signal analysis method. Scale-space filtering can extract highest frequency factors(noise) effectively. But scale-space filtering has too large calculation costs and end effect problems. This research reduces the calculation cost of scale-space filtering by applying the minimum limit to the gaussian kernel. And the end-effect that occurs at the end of the signal of the scale-space filtering is overcome by using extrapolation related with the clustering change detection method. Nonlinear principal component analysis methods using neural network have been reviewed and the separately expanded functional-link associative neural network is proposed for chemical process monitoring. The separately expanded functional-link associative neural network has better learning capabilities, generalization abilities and short learning time than the exiting-neural networks. Separately expanded functional-link associative neural network can express a statistical model similar to real process by expanding the input data separately. Combining the proposed methods-modified scale-space filtering and fault detection method using the separately expanded functional-link associative neural network-a process monitoring system is proposed in this research. the usefulness of the proposed method is proven by its application a boiler water supply unit.

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공간, 시간, 사회/자연의 상호관계성에 의한 지역이해 (Understanding of Region As an Interaction among Space, Time, and Society)

  • 박규택;이상률
    • 한국지역지리학회지
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    • 제5권2호
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    • pp.15-27
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    • 1999
  • 본 연구는 역동적이고 포괄적으로 지역을 이해하기 위한 개념적 틀을 수립하는 것이 목적이며, 이를 위해 공간, 시간, 사회/자연의 상호관계성에 대해서 논의를 하였다. 지역은 자연적 혹은 객관적으로 주어진 것이 아니라, 물리적 공간에 기반을 둔 사회적 인식과 실천에 의해 (재)생산될 뿐만 아니라, 사회를 변화시키는 능동적 요인으로 작용하는 관점으로 이해되어야 한다. 이러한 관점을 구체화시키기 위해 공간, 시간, 사회/자연의 상호관계성이 수립되어야 한다. 특히, 공간과 사회의 관계에 관한 이론을 수립하려는 다양한 사회이론은 역사, 사회적 관점에서 공간과 시간의 관계 그러고 사회와 자연의 관계에 대한 연구를 진전시키지 않았다. 공간, 시간, 사회/자연을 보다 중첩적으로 이해하기 위해 공간과 시간의 규모의 관계에 대한 이론적 연구가 필요하다.

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Flux Monitoring of Intraday Variable Source with the KVN Ulsan Radio Telescope

  • 이지원;손봉원;변도영;김성수
    • 천문학회보
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    • 제36권2호
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    • pp.60.2-60.2
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    • 2011
  • We introduce the preliminary results of flux monitoring of BL Lac object 0716+714 with the KVN Ulsan 21m radio telescope. This radio source is well known as the intraday variable (IDV) source which is characterized by the rapid flux variation on the time scale of a day or less. In general, the IDV phenomenon is interpreted as the effect of refractive scintillation in the interstellar medium or the evidence of intrinsic flux variation. In previous observations that took a few days, however, it had not been detected the flux variation of short time scale but the monotonic increase and decrease. Therefore, to investigate the longer time scale of 0716+714, we had the flux variation monitoring at 22GHz and 43GHz simultaneously for 9 months from October 2010 to June 2011. We present here the structure functions and the cross correlation functions between different frequencies as well as the light curves.

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Comparing the statistics of isothermal compressible turbulence in simulation : Single versus Double forcing

  • 유현주;조정연
    • 천문학회보
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    • 제36권2호
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    • pp.108.1-108.1
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    • 2011
  • Turbulence is ubiquitous in astrophysical fluids such as the interstellar medium(ISM) and the intracluster medium(ICM). There are many driving mechanisms which can inject energy into the fluid in variety driving scales, But the plausible driving scale of ISM/ICM turbulence are yet unknown. Therefore, understanding different statistical properties between turbulence with single driving scale and turbulence with double driving scale is required. In this work, we performed 3-dimensional isothermal compressible, magnetohydrodynamic(MHD) turbulence simulations. We drive turbulence in the Fourier space in two ranges, 2

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Storm-Time Behaviour of Meso-Scale Field-Aligned Currents: Case Study with Three Geomagnetic Storm Events

  • Awuor, Adero Ochieng;Baki, Paul;Olwendo, Joseph;Kotze, Pieter
    • Journal of Astronomy and Space Sciences
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    • 제36권3호
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    • pp.133-147
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    • 2019
  • Challenging Minisatellite Payload (CHAMP) satellite magnetic data are used to investigate the latitudinal variation of the storm-time meso-scale field-aligned currents by defining a new metric called the FAC range. Three major geomagnetic storm events are considered. Alongside SymH, the possible contributions from solar wind dynamic pressure and interplanetary magnetic field (IMF) $B_Z$ are also investigated. The results show that the new metric predicts the latitudinal variation of FACs better than previous studies. As expected, the equatorward expansion and poleward retreat are observed during the storm main phase and recovery phase respectively. The equatorward shift is prominent on the northern duskside, at ${\sim}58^{\circ}$ coinciding with the minimum SymH and dayside at ${\sim}59^{\circ}$ compared to dawnside and nightside respectively. The latitudinal shift of FAC range is better correlated to IMF $B_Z$ in northern hemisphere dusk-dawn magnetic local time (MLT) sectors than in southern hemisphere. The FAC range latitudinal shifts responds better to dynamic pressure in the duskside northern hemisphere and dawnside southern hemisphere than in southern hemisphere dusk sector and northern hemisphere dawn sector respectively. FAC range exhibits a good correlation with dynamic pressure in the dayside (nightside) southern (northern) hemispheres depicting possible electrodynamic similarity at day-night MLT sectors in the opposite hemispheres.

소규모·다기능 고령자주택의 공간구성과 유형에 관한 연구 - 일본 동경권 사례를 중심으로 - (A Study on Type and Space Composition in the Small Scale and Multi-functional Housing - focused on the cases of the Tokyo area -)

  • 소갑수
    • 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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    • 제13권1호
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    • pp.17-26
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    • 2007
  • Recently, the importance of the living environment for elderly people and its network is increasing. At the same time, the small-scale and multi-functional apartment house in which they can live is continuously required in Japan. For these reasons, it is appearing a new type of housing, Group-Living, where one lives together with others. It represents a way of communal living which is based on service at home. There are various problems such as felicity of each space, connections between the different areas, insufficiency of positioning on the aged welfare. Hence this research targets are grasp the present condition of Group-Living, to inquire the Space composition and types of it in Tokyo Area, and to suggest the direction of improvement of the small-scale and multi-functional apartment house for the aged.

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THE SPACE-TIME FRACTIONAL DIFFUSION EQUATION WITH CAPUTO DERIVATIVES

  • HUANG F.;LIU F.
    • Journal of applied mathematics & informatics
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    • 제19권1_2호
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    • pp.179-190
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    • 2005
  • We deal with the Cauchy problem for the space-time fractional diffusion equation, which is obtained from standard diffusion equation by replacing the second-order space derivative with a Caputo (or Riemann-Liouville) derivative of order ${\beta}{\in}$ (0, 2] and the first-order time derivative with Caputo derivative of order ${\beta}{\in}$ (0, 1]. The fundamental solution (Green function) for the Cauchy problem is investigated with respect to its scaling and similarity properties, starting from its Fourier-Laplace representation. We derive explicit expression of the Green function. The Green function also can be interpreted as a spatial probability density function evolving in time. We further explain the similarity property by discussing the scale-invariance of the space-time fractional diffusion equation.

특이섭동 모델역변환을 이용한 멀티콥터 위치제어 연구 (Multicopter Position Control using Singular Perturbation based Dynamic Model Inversion)

  • 최형식;정연득;이장호;유혁;이상종
    • 한국항공우주학회지
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    • 제45권4호
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    • pp.276-283
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    • 2017
  • 본 논문은 4개의 로터를 가지는 쿼드콥터에 대한 비선형 운동모델을 구성하고, 특이섭동 기법을 이용한 모델 역변환 위치 제어기 설계 결과에 대해 나타낸다. 특이섭동 모델 역변환방식은 느린 동역학과 빠른 동역학을 시분할 기법(time scale separation)기법을 이용하여 각각 역변환 시키는 방법이다. 수립한 6자유도 비선형 운동모델 기반으로, 모델 역변환 제어기를 설계하고 시뮬레이션을 수행한 결과 정확한 위치 추종을 수행함을 확인하였다.