• Journal of Astronomy and Space Sciences
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• 제31권1호
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• pp.7-13
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• 2014

Variabilities in the solar wind cause disturbances throughout the heliosphere on all temporal and spatial scales, which leads to changeable space weather. As a view of space weather forecasting, in particular, it is important to know direct and indirect causes modulating the space environment near the Earth in advance. Recently, there are discussions on a role of the interaction of the solar wind with Mercury in affecting the solar wind velocity in the Earth's neighborhood during its inferior conjunctions. In this study we investigate a question of whether other parameters describing the space environment near the Earth are modulated by the inner planets' wake, by examining whether the interplanetary magnetic field and the proton density in the solar wind observed by the Advanced Composition Explorer (ACE) spacecraft, and the geomagnetic field via the Dst index and Auroral Electrojet index (AE index) are dependent upon the relative position of the inner planets. We find there are indeed apparent variations. For example, the mean variations of the geomagnetic fields measured in the Earth's neighborhood apparently have varied with a timescale of about 10 to 25 days. Those variations in the parameters we have studied, however, turn out to be a part of random fluctuations and have nothing to do with the relative position of inner planets. Moreover, it is found that variations of the proton density in the solar wind, the Dst index, and the AE index are distributed with the Gaussian distribution. Finally, we point out that some of properties in the behavior of the random fluctuation are to be studied.

• 한국조경학회지
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• 제30권3호
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• pp.1-11
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• 2002

The purpose of this study is to construct an evaluation criteria based on the relative importance and various combinations of each evaluation index and then to appraise urban biotope in terms of nature experience and recreation. After the standard of evaluation had been developed through the review of existing literature, the relative importance of the evaluation index through expert survey was determined, and the evaluation model to assess biotope value was established. The results of this study are as follows; 1) We have constructed the seventeen evaluation criteria through literature reviews, and have provided relative importance to each evaluation index of the natural in biotope, the diversity of landscape patterns, the appearance-existence of water space, the special landscape elements, and the access based on the results of expert survey. and then we have constructed an evaluation system using the relative importance criteria. 2) To evaluate urban biotope using the evaluation system constructed, we selected 14 sites. The final evaluation results of each site is as follows; The first grade areas are the water space with semi-natural style in front of Gangchon Woobang apartments, the forest zone near Page Temple at Mt. Palgong, the edge area of Jisan and Gosan and the tendril yard against Anshim middle school. The second grade areas are Hyomyung elementary school, the farm land behind the third Anshim Jugong apartment, Ehyun put and the swampy land in front of the Kangchon and Anshim construction site. The third grade areas are Seohan and Hwasung high-rise apartments at Beummul-Dong, the Korea Manpower Agency in the Sungseo industrial zone, and the adjacent area of St. Tongil. The only fourth grade area is the commercial zone near Taegu Department Store. 3) It is highly useful to evaluate urban biotope using the evaluation criteria constructed for this research, the evaluation criteria we developed may be difficult to encompass all expert opinion and the period of space-formation is difficult to estimate urban biotopes. In the future, it is necessary to gather the basic data suitable to estimate biotope and it is necessary to develop detailed evaluation criteria applicable to estimate every biotope that has specific property.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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• pp.24.2-24.2
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• 2008

We have examined the relative contributions of representative space weather proxies (geomagnetic aa index) to global warming (Global temperature anomaly) and compared them with that of green house effect characterized CO2 content from 1868 to 2005. For this we used Hadcrut3 temperature anomaly (Ta) data, aa index taken at two anti-podal subauroral stations (Canberra Australia and hartland England), and the CO2 data come from historical ice core records. From the comparison between Ta and aa index, we found several interesting results: (1) the linear correlation coefficient between two parameters increases until 1990 and then decreases rapidly, and (2) the scattered plots between two parameters shows different patterns before and after 1990. A partial correlation of Ta and two quantities (aa, CO2) also shows that the geomagnetic effect (aa index) is dominant until about 1990 and the CO2 effect becomes much more important after then. These results imply that the green house effect become very important since at least 1990. For a further analysis, we simply assume that Ta (total) = Ta (aa) + Ta (CO2) and made a linear regression between Ta and aa index from 1868 to 1990. A linear model is then made from the linear regression between energy consumption (a proxy of CO2 effect) and Ta (total) - Ta (aa) since 1990. This linear model makes it possible to predict the temperature anomaly in 2030, about 1 degree higher than the present temperature, which is much larger than in the previous century.

• Journal of Astronomy and Space Sciences
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• 제33권2호
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• pp.137-146
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• 2016

The correlation between meteorological data collected at the optical wide-field patrol network (OWL-Net) Station No. 1 and the seeing of satellite optical observation data was analyzed. Meteorological data and satellite optical observation data from June 2014 to November 2015 were analyzed. The analyzed meteorological data were the outdoor air temperature, relative humidity, wind speed, and cloud index data, and the analyzed satellite optical observation data were the seeing full-width at half-maximum (FWHM) data. The annual meteorological pattern for Mongolia was analyzed by collecting meteorological data over four seasons, with data collection beginning after the installation and initial set-up of the OWL-Net Station No. 1 in Mongolia. A comparison of the meteorological data and the seeing of the satellite optical observation data showed that the seeing degrades as the wind strength increases and as the cloud cover decreases. This finding is explained by the bias effect, which is caused by the fact that the number of images taken on the less cloudy days was relatively small. The seeing FWHM showed no clear correlation with either temperature or relative humidity.

• Journal of Astronomy and Space Sciences
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• 제26권3호
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• pp.317-328
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• 2009

위성의 상대운동 모델은 두 위성 사이의 상대적인 운동을 기술하며, 위성편대비행 연구의 기본이 된다. 이 연구에서는 선형 및 비선형 상대운동 모델들의 정확도를 산출하고 이를 비교 분석하였다. 우선 모델의 정확도를 나타내는 '모델링 오차 지수(Modeling Error Index)'를 정의하였다. 다양한 주위성 궤도의 이심률과 두 위성 사이의 거리에 대해 모델링 오차 지수를 계산하여, 여러 궤도환경에 따른 기존의 여러 가지 상대운동 모델들의 정확도를 산출하였다. 여러 가지 상대운동 방정식들의 모델링 오차 지수는 주위성의 이심률의 크기, J2 섭동 고려 여부, 위성들의 상대 거리의 크기에 따라 달라진다. 이 연구에서 사용한 상대운동 모델의 정확도는 편대비행 동역학모델의 오차를 나타내므로, 이 연구 결과를 이용해서 주어진 편대비행 임무에 알맞은 모델을 선택하는 것이 가능하다.

• 환경영향평가
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• 제31권6호
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• pp.438-448
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• 2022

본 연구는 공간계획 단계에서 생태적 건전성 향상을 유도할 수 있는 계획수단으로 환경생태계획 기법과 환경계획지표인 생태면적률의 정량적인 산정지표를 개선하기 위한 연구이다. 현재 운영 중인 공간유형 및 산정지표에 대해 상대적 중요도를 파악하고 공간유형 및 가중치의 개선에 대한 의견분석을 통해 대안을 찾고자 한다. 본 연구의 방법으로는 공간유형 및 산정지표의 심층분석을 위한 공간유형의 상대적 중요도 평가를 위한 AHP 분석을 실시하였다. 연구의 신뢰성과 객관성을 확보하기 위하여 전문가 50인이 참여하였다. 본 연구를 통해 생태면적률 유형별 한계점과 개선에 대한 의견분석을 통해 발전하는 기술과 공법, 유지관리 효율성, 경제성, 시공기술의 향상 등과 연계한 생태면적률 적용을 통해 도시환경의 개선과 생태면적률 활성화에 기여할 것으로 기대된다.

• 한국항공우주학회지
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• 제44권7호
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• pp.629-639
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• 2016

지형상대항법은 측정된 지형고도와 DEM(Digital Elevation Map)의 지형고도의 비교를 통해 위치보정이 이루어지는 시스템이다. 하지만 지형상대항법은 언덕과 같은 반복되는 지형과 같이 측정된 지형고도 프로파일과 후보 지형고도 프로파일이 유사할 때 다른 지형으로 오보정을 유발 할 수 있는 단점을 가지고 있어 항법 성능이 떨어지는 것으로 알려져 있다. 본 논문에서는 이러한 단점을 극복하기 위해 관심영역 안에 주변 지형의 유사한 정도를 판단하는 영역기반 지형 기울기 험준도 지수를 적용하였고[11], 영역기반 지형 곡률 험준도 지수를 제안하였다. 제안한 지형 험준도 지수의 성능 검증을 위하여 기존의 궤적기반 지형 험준도 지수와 영역기반 지형 험준도 지수를 달착륙선의 지형상대항법에 적용한 시뮬레이션을 수행하였다. 그 결과, 기존의 궤적기반 지형 험준도 지수를 고려하였을 때 보다 영역기반 지형 험준도 지수를 고려하였을 때 지형상대항법 성능이 개선됨을 확인하였다.

• 한국정보과학회논문지:데이타베이스
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• 제30권3호
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• pp.225-236
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• 2003

다차원 온라인 분석처리 (MOLAP, Multidimensional On-line Analytical Processing) 시스템은 데이타를 큐브라고 불리는 다차원 배열에 저장하고 배열 인덱스를 이용하여 데이타를 엑세스한다. 큐브를 디스크에 저장할 때 각 변의 길이가 같은 작은 청크들로 조각내어 저장하게 되면 데이타 클러스터링 효과를 통해 모든 차원에 공평한 질의 처리 성능이 보장되며, 이러한 큐브 저장 방법을 ‘청크기반 MOLAP 큐브’ 저장 방법이라고 부른다. 공간 효율성을 높이기 위해 밀도가 낮은 청크들은 또한 압축되어 저장되는데 이 과정에서 데이타의 상대 위치 정보가 상실되며 원하는 청크들을 신속하게 엑세스하기 위해 인덱스가 필요하게 된다. 본 연구에서는 비트맵을 사용하여 청크기반 MOLAP 큐브를 인덱싱하는 방법을 제시한다. 인덱스는 큐브가 생성될 때 동시에 생성될 수 있으며, 인덱스 수준에서 청크들의 상대 위치 정보를 보존하여 청크들을 상수 시간에 검색할 수 있도록 하였고, 인덱스 블록마다 가능한 많은 청크들의 위치 정보가 포함되도록 하여 범위 질의를 비롯한 OLAP 주요 연산 처리 시에 인덱스 엑세스 회수를 크게 감소시켰다. 인덱스의 시간 공간적 효율성은 다차원 인덱싱 기법인 UB-트리, 그리드 파일과의 비교를 통해 검증하였다.

• 한국환경과학회지
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• 제24권5호
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• pp.689-697
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• 2015

Based on the survey of 4 universities in Tai' an by questionnaire survey and interviews, this study acquired and analyzed the college student users' activity type, utilization frequency, retention time, companion, preference for landscape design style, the importance of the courtyard space's environment and landscape, as well as correlations between primary attributes and activity characteristics of student users. The weight of the university teaching area's courtyard space evaluation index was obtained by Analytical Hierarchy Process. The results indicated that nearly 60% college students select to study and to rest alone as the main activity type, 80% students' utilization frequency is at least two times or more a week. In addition, the relative weight of plant landscape is the highest in the 2nd class indexes of space garden landscape, and its value is 0.113; the relative weight of cleanliness is the highest in the 3rd class indexes of space environment quality, and its value is 0.143. Therefore, it should be attached much importance to constructing the environment and landscape for studying and relaxing, and the factors of cleanliness and plant landscape etc in the further design of courtyard space are taken into full consideration.

• 천문학회보
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• 제41권1호
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• pp.79.3-80
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• 2016

We have investigated the correlation analysis between global temperature anomaly and two main factors: geomagnetic activity (aa index) of Earth external factor and CO2 of Earth internal factor. For this, we used NOAA Global Surface Temperature anomaly (Ta) data from 1868 to 2015. The aa index indicates the geomagnetic activity measured at two anti-podal subauroral stations (Canberra Australia and Hartland England) and the CO2 data come from historical ice core records and NOAA/ESRL data. From the comparison between (Ta) and aa index, we found several interesting things, First, the linear correlation coefficient between two parameters increases until 1985 and then decreases rapidly. Second, the scattered plot between two parameters shows a boundary of the correlation tendency (positive and negative correlation) near 1985. A partial correlation of (Ta) and two main factors (aa index, CO2) also shows that the geomagnetic effect (aa index) is dominant until about 1985 and the CO2 effect becomes much more important after then. These results indicate that the CO2 effect become very an important factor since at least 1985. For a further analysis, we simply assume that Ta = Ta(aa)+Ta(CO2) and made a linear regression between (Ta) and aa index from 1868 to 2015. A linear model is then made from the linear regression between energy consumption (a proxy of CO2 effect) and Ta-Ta(aa) since 1985. Our results will be discussed in view of the prediction of global warming.