지상지자기변화기록을 이용한 우주천기연구

안병호 한국천문학회 2000 天文學論叢 Vol.15 No.3

Through the coupling between the near-earth space environment and the polar ionosphere via geomagnetic field lines, the variations occurred in the magnetosphere are transferred to the polar region. According to recent studies, however, the polar ionosphere reacts not only passively to such variations, but also plays active roles in modifying the near-earth space environment. So the study of the polar ionosphere in terms of geomagnetic disturbance becomes one of the major elements in space weather research. Although it is an indirect method, ground magnetic disturbance data can be used in estimating the ionospheric current distribution. By employing a realistic ionospheric conductivity model, it is further possible to obtain the distributions of electric potential, field-aligned current, Joule heating rate and energy injection rate associated with precipitating auroral particles and their energy spectra in a global scale with a high time resolution. Considering that the ground magnetic disturbances are recorded simultaneously over the entire polar region wherever magnetic station is located, we are able to separate temporal disturbances from spatial ones. On the other hand, satellite measurements are indispensible in the space weather research, since they provide us with in situ measurements. Unfortunately it is not easy to separate temporal variations from spatial ones specifically measured by a single satellite. To demonstrate the usefulness of ground magnetic disturbance data in space weather research, various ionospheric quantities are calculated through the KRM method, one of the magneto gram inversion methods. In particular, we attempt to show how these quantities depend on the ionospheric conductivity model employed.

다자간 멀티미디어 응용의 멀티캐스트 통신환경을 위한 통합 관리 플랫폼

안병호,고석주,김용진,함진호,차호정,조국현 한국통신학회 1999 韓國通信學會論文誌 Vol.24 No.12

본 논문은 최근 다자간 멀티미디어 응용들의 출현과 더불어 중요한 전송 방식으로 대두되고 있는 멀티캐스트 통신환경의 다양한 관리 문제들을 해결하기 위한 통합 관리 플랫폼(IPME)을 제안한다. 이를 위해서 본 논문은 먼저 대부분이 다자간 멀티미디어 응용들에서 사용하는 멀티캐스트 통신환경의 문제점 및 관련 연구들을 기술하고, 관리플랫폼의 구현을 위한 설계 요건들을 기술 한 후, 이러한 요건들을 기반으로 멀티캐스트 통신환경을 통한 통합 관리하기 위한 플랫폼의 일반적 구조를 제안한다. 또한 제안된 관리 플랫폼이 제공할 수 있는 멀티캐스트 관리서비스들, 시스템 일반 구조, 기능 모듈들, 이를 실행하기 위한 관리절차, 관리설정단계, 관리 정책 및 관리 정보의 저장을 위한 관리정보베이스(MIB)구조 등의 관리 구조들도 제안한다. 제안된 IPME 구조의 타당성을 검증하기 위해서 멀티캐스트 통신환경을 이용하는 H.263 부호화 복호화 시스템에 대한 멀티캐스트 QoS 관리서비스에 적용하여 설계하고 이에 대한 프로타입 시스템을 구현한다. This paper, proposes an integrated management platform to solve various management issues for multicast environments, which have been considered as an important transfer method together the appearance of multipeer applications recently(i.e,. IPME). First of all this paper describes the problems and related works of multicast environments, and proposes the general architecture of a management platform to manage multicast environments after considering design requirements to implement a proposed platform. This paper also proposes the management services to be provided, a general system architecture, its functional modules, and the management architecture such as a management procedure, establishment phases, management policies, and a Management Information Base(MIB) structure. In order to verify the proposed IPME, it is also applied and implemented as prototyping system to the QoS management service for H.263 video encoding/decoding system, that is IPME-QoS, which currently is a critical issue and uses multicast environments.

헬리곱터 로우터 구동 시스템 설계 및 해석기법 개발

안병호,이동호 한국항공우주학회 1994 한국항공우주학회 학술발표회 논문집 Vol.- No.-

언어 대비와 발음교육

안병호 이화여자대학교 한국어문학연구소 2004 Korean 교육 학술토론회 자료집 Vol.2004 No.1

CI 기본 시스템 구축을 위한 체계적 프로세스

안병호,정경원 한국디자인학회 1996 디자인학연구 Vol.- No.16

Response of the Geomagnetic Activity Indices to the Solar Wind Parameters

안병호,박윤경 한국우주과학회 2008 Journal of Astronomy and Space Sciences Vol.25 No.2

This study attempts to show how the geomagnetic indices, AU, AL and Dst, respond to the interplanetary parameters, more specifically, the solar wind electric field VBz during southward interplanetary magnetic field (IMF) period. The AU index does not seem to respond linearly to the variation of southward IMF. Only a noticeable correlation between the AU and VBz is shown during summer, when the ionospheric conductivity associated with the solar EUV radiation is high. It is highly likely that the effect of electric field on the eastward electrojet intensification is only noticeable whenever the ionospheric conductivity is significantly enhanced during summer. Thus, one should be very cautious in employing the AU as a convection index during other seasons. The AL index shows a significantly high correlation with VBz regardless of season. Considering that the auroral electrojet is the combined result of electric field and ionospheric conductivity, the intensification of these two quantities seems to occur concurrently during southward IMF period. This suggests that the AL index behaves more like a convection index rather than a substorm index as far as hourly mean AL index is concerned. Contrary to the AU index, the AL index does not register the maximum value during summer for a given level of VBz. It has something to do with the findings that discrete auroras are suppressed in sunlight hemisphere (Newell et al. 1996), thus reducing the ionospheric conductivity during summer. As expected, the Dst index tends to become more negative as VBz gets intensified. However, the Dst index (nT) is less than or equal to 15 VBz (mV/m) + 50 (Bz < 0). It indicates that VBz determines the lower limit of the storm size, while another factor(s), possibly substorm, seems to get further involved in intensifying storms. Although it has not been examined in this study, the duration of southward IMF would also be a factor to be considered in determining the size of a storm. This study attempts to show how the geomagnetic indices, AU, AL and Dst, respond to the interplanetary parameters, more specifically, the solar wind electric field VBz during southward interplanetary magnetic field (IMF) period. The AU index does not seem to respond linearly to the variation of southward IMF. Only a noticeable correlation between the AU and VBz is shown during summer, when the ionospheric conductivity associated with the solar EUV radiation is high. It is highly likely that the effect of electric field on the eastward electrojet intensification is only noticeable whenever the ionospheric conductivity is significantly enhanced during summer. Thus, one should be very cautious in employing the AU as a convection index during other seasons. The AL index shows a significantly high correlation with VBz regardless of season. Considering that the auroral electrojet is the combined result of electric field and ionospheric conductivity, the intensification of these two quantities seems to occur concurrently during southward IMF period. This suggests that the AL index behaves more like a convection index rather than a substorm index as far as hourly mean AL index is concerned. Contrary to the AU index, the AL index does not register the maximum value during summer for a given level of VBz. It has something to do with the findings that discrete auroras are suppressed in sunlight hemisphere (Newell et al. 1996), thus reducing the ionospheric conductivity during summer. As expected, the Dst index tends to become more negative as VBz gets intensified. However, the Dst index (nT) is less than or equal to 15 VBz (mV/m) + 50 (Bz < 0). It indicates that VBz determines the lower limit of the storm size, while another factor(s), possibly substorm, seems to get further involved in intensifying storms. Although it has not been examined in this study, the duration of southward IMF would also be a factor to be considered in determining the size of a storm.

極地方 電離層의 電磁氣的 物理量의 推定(Ⅰ) : 方法

안병호 한국지구과학회 1991 韓國地球科學會誌 Vol.12 No.2

The magnetogram inversion technique (MIT) is a computational method for calculating the global pattern of ionospheric current using ground magnetic disturbance data as input. By assuming the ionospheric electric conductivity distribution, the technique makes it further possible to estimate the distribution patterns of such electrodynamic quantities as electric field, electric potential, field-aligned current and Joule heating rate. Although the MIT is an indirect method, it provides instantaneous electrodynamical pictures of the entire polar ionosphere with a high time resolution while more direct measurements by radar, rocket and satellite are vital to understand the ionospheric phenomena but they provide informations only over a limited area. Since the output of the MIT are very sensitive to the choice of the ionospheric conductivity distribution, a companion paper will be devoted to the topic. Various electrodynamic quantities over the polar ionosphere, which are now available through the magnetogram inversion technique, will be also discussed in another companion paper.

極地方 電離層의 電氣 傳導度 分布(Ⅱ)

安炳鎬 한국지구과학회 1992 韓國地球科學會誌 Vol.13 No.1

The magnetogram inversion technique (MIT) has been demonstrated as a powerful $quot;remote sensing tool$quot; in estimating ionospheric quantities, such as ionospheric current, field-aligned current, electric potential and Joule heating rate etc. Furthermore it is now possible to infer instantaneous patterns of such global distributions with a high time resolution (say, 5 min) through the numerical method. However, the electric potential distribution estimated from the MIT is very sensitive to the choice of ionospheric conductivity models. It is a serious drawback of the method, since the electric potential over the polar region is a very important quantity reflecting the efficiency of the solar wind-magnetosphere coupling. Thus a realistic conductivity distribution over the entire polar ionosphere is acute. In this paper, we introduce a general concept of ionospheric electric conductivity along with several methods of estimating it.

오로라제트전류대의 계절, 태양주기 및 세계시에 따른 변화

안병호 한국우주과학회 2002 한국우주과학회보 Vol.11 No.2

오로라의 신비

안병호,An, Byeong-Ho 한국과학기술단체총연합회 1994 과학과 기술 Vol.27 No.2