• 한국항공운항학회지
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• 제22권1호
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• pp.136-144
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• 2014

This paper studied what kind of effects were made through Open Sky agreement on Korea-China air transport market. To analyze the effects on air transport markets brought by liberalization, this paper studied transport volume, number of airlines, passenger and cargo and routes from 2000 to 2012 Korea-China aviation statistics. Liberalization of shandong and Hainan Provinces agreed in 2006 caused significant differences in frequencies, transport volume, and the number of routes for both passenger and cargo services between 2007 and 2008, as well as statistically significant effects. The analysis on the effect of Korea-China Open skies Agreement between 2000 and 2012 was no difference because the global financial crisis in September 2008.

• 지구물리
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• 제9권4호
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• pp.361-369
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• 2006

본 연구에서는 AHRS IMU 센서를 이용하여 동적 위치 결정을 위해 초기화 시험을 실시하여 회귀분석을 통해 시간에 대한 이동체의 자세 보정각에 대해 유도하였으며, 동체 방향(Heading)각의 경우 60sec를 지난 후 1°이내의 변동률로 안정되는 것을 알 수 있었다. 이를 바탕으로 개할지와 준개할지로 구분하여 각 시스템 단독으로 동적 위치결정을 실험한 결과 개할지의 DGPS 단독 시스템인 경우 정확도 면에서는 우수하였지만 데이터 취득이 미비하여 이동간 거리가 12m 내외임을 알 수 있었으며, DGPS/IMU 결합 시스템의 경우 정확도와 데이터 취득 및 이동간 거리가 0.3m 내외임을 알 수 있었다. 준개할지에서 DGPS 단독 시스템의 경우 데이터 취득이 불가능한 곳을 제외하고 평균과 표준 오차를 구한 결과 DGPS〈 FIMU〈 DGPS/IMU 순으로 정확도가 우수한 것을 알 수 있었으며 이동간 거리는 개할지와 마찬가지였다. 그리고 DGPS의 경우 데이터 취득이 불가능한 곳을 여러 구간으로 비교하였을 때 DGPS 단독 시스템의 경우 최대 41.5m 가량 궤적에서 벗어나지만 결합 시스템의 경우 최대 2.2m 이내에 궤적을 구할 수 있었으며, 평균과 표준 오차를 크게 향상시킬 수 있었다. 이러한 항법 시스템을 결합하여 측량분야에 응용해 수치도화 작업내규의 지도에서 위치오차 0.2mm 오차와 비교하였을 때 축척 1 : 1,000 수치지도 작업까지도 가능한 것을 알 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.631-634
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• 2014

웹과 클라우드 컴퓨팅 환경 구축시에 필수적으로 사용되는 것이 데이터베이스 시스템이다. 이러한 데이터베이스 시스템에는 오라클과 MS-SQL 등과 같은 상용 프로그램도 있지만, 상용 프로그램에 필적할 성능을 가진 무료 프로그램도 다수 존재한다. 특히, PostgreSQL, MySQL, MariaDB 등은 비용도 들지 않지만, 소스도 공개되어 있어서 다양한 환경에 적용할 수 있다. 본 논문에서는 소스가 공개된 관계형 데이터베이스 관리 시스템의 동향에 대해 알아본다.

• 한국항행학회논문지
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• 제16권6호
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• pp.944-951
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• 2012

위성항법의 가시성, Dilution of Precision (DOP), 신호대잡음비 등과 같은 위치결정 성능지표는 개활지 환경과 같이 항법위성의 가시성이 좋은 지역에서 그 활용도가 높으며, 육상교통환경의 경우 그 활용도가 낮다. 본 논문은 육상교통환경에서 위성항법 신호를 활용하여 위치결정을 수행하는 경우 활용도가 높은 성능지표로 Sky View based DOP (SVDOP)을 제안한다. SVDOP은 Sky-View Factor(SVF)를 응용하여 개발되었으며, 기존의 SVF의 문제점을 극복할 수 있다. Sky-View 영상을 활용하여 특징점을 선택하고 이를 활용하여 DOP를 계산할 수 있다. 제안된 방법을 이용하는 경우 SVF 사용보다 육상교통환경에서 위치결정 성능 예측에 용이함을 확인할 수 있다.

• 천문학논총
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• 제32권1호
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• pp.305-307
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• 2017

We have identified 22 quasars in the AKARI far-infrared all-sky Bright Source Catalogue, using a matching radius of < 10", and excluding matches which are close to foreground extended sources or cirrus. We have confirmed a relation between quasar optical luminosity and far-infrared luminosity which was found in an earlier study. In addition, we have found that the 11 sources which are at redshift z > 1 are magnified with respect to the predicted far-infrared luminosity, and consider this may be due to gravitational lensing. If confirmed, this would provide a new way to identify lenses; if not, we may have identified an interesting new population of extreme starbursting quasars.

• 항공우주정책ㆍ법학회지
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• 제22권2호
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• pp.135-154
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• 2007

The 3 Northeast Asian countries of Korea, Japan and China have been stricter to each other than to other countries of out-region in air liberalization. The prominent reason of this intra-regional protective policy in air transportation seems to be the difference in competitive strength of their national flag carriers. As the 3 countries realize the importance of their mutual cooperation in the region, since China grows to be one of the leading economies in the world and the intra-regional trade and visitors increase tremendously, they are now taking the policy of intra-regional air liberalization more vigorously than before. Especially air cargo liberalization is easier than air passenger liberalization because they realize that the development of open economy is based on free flow of logistics regardless of the competitiveness of their national flag carriers. As Korea is the leading country in the region to promote air liberalization, this paper reviews the importance and growing trend of air cargo, analyzes current air liberalization policy between Korea, Japan and China and the initial effects of open sky in the routes of Shandung-Korea, and suggests the new policies of air liberalization to promote free flow of air logistics.

• 천문학논총
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• 제27권4호
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• pp.111-116
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• 2012

Far-infrared observations provide crucial data for the investigation and characterisation of the properties of dusty material in the Interstellar Medium (ISM), since most of its energy is emitted between ~ 100 and $200{\mu}m$. We present the first all-sky image from a sensitive all-sky survey using the Japanese AKARI satellite, in the wavelength range $50-180{\mu}m$. Covering > 99% of the sky in four photometric bands with four filters centred at $65{\mu}m$, $90{\mu}m$, $140{\mu}m$, and $160{\mu}m$ wavelengths, this achieved spatial resolutions from 1 to 2 arcmin and a detection limit of < 10 MJy $sr^{-1}$, with absolute and relative photometric accuracies of < 20%. All-sky images of the Galactic dust continuum emission enable astronomers to map the large-scale distribution of the diffuse ISM cirrus, to study its thermal dust temperature, emissivity and column density, and to measure the interaction of the Galactic radiation field and embedded objects with the surrounding ISM. In addition to the point source population of stars, protostars, star-forming regions, and galaxies, the high Galactic latitude sky is shown to be covered with a diffuse filamentary-web of dusty emission that traces the potential sites of high latitude star formation. We show that the temperature of dust particles in thermal equilibrium with the ambient interstellar radiation field can be estimated by using $90{\mu}m$, $140{\mu}m$, and $160{\mu}m$ data. The FIR AKARI full-sky maps provide a rich new data set within which astronomers can investigate the distribution of interstellar matter throughout our Galaxy, and beyond.

• 천문학논총
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• 제32권1호
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• pp.11-15
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• 2017

We present the AKARI far-infrared (FIR) all-sky maps and describe its characteristics, calibration accuracy and scientific capabilities. The AKARI FIR survey has covered 97% of the whole sky in four photometric bands, which cover continuously 50-180 micron with band central wavelengths of 65, 90, 140, and 160 microns. The data have been publicly released in 2014 (Doi et al., 2015) with improved data quality that have been achieved since the last internal data release (Doi et al., 2012). The accuracy of the absolute intensity is ${\leq}10%$ for the brighter regions. Quantitative analysis of the relative intensity accuracy and its dependence upon spatial scan numbers has been carried out. The data for the first time reveal the whole sky distribution of interstellar matter with arcminute-scale spatial resolutions at the peak of dust continuum emission, enabling us to investigate large-scale distribution of interstellar medium in great detail. The filamentary structure covering the whole sky is well traced by the all-sky maps. We describe advantages of the AKARI FIR all-sky maps for the study of interstellar matter comparing to other observational data.

• 천문학회보
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• 제35권1호
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• pp.41.2-41.2
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• 2010

The infrared astronomy satellite AKARI/FIS (Far-Infrared Surveyor) performed all-sky survey in 4 Far-IR bands (50 - 200${\mu}m$ range). It observed around 94% of the whole sky twice or more with a higher spatial resolution and a wider wavelength coverage than that of previous all-sky mission, IRAS. The AKARI/FIS bright source catalogue ${\beta}-2$ is the second released version which included around 290,000 point sources. It provides us with more reliable position and flux information, and around 4 times larger number of sources compared with the first version of catalogue. The sensitivity limit at $90{\mu}m$ band is 0.6 Jy and the estimated flux uncertainty is 20-35% for bright sources. The catalogue will be open to public in this year after the improvement of accuracy, reliability and completeness.

• Asian Journal of Atmospheric Environment
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• 제7권1호
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• pp.25-37
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• 2013

Open biomass burning (excluding biofuels) is an important contributor to air pollution in the Asian region. Estimation of emissions from fires, however, has been problematic, primarily because of uncertainty in the size and location of sources and in their temporal and spatial variability. Hence, more comprehensive tools to estimate wildfire emissions and that can characterize their temporal and spatial variability are needed. Furthermore, an emission processing system that can generate speciated, gridded, and temporally allocated emissions is needed to support air-quality modeling studies over Asia. For these reasons, a biomass-burning emissions modeling system based on satellite imagery was developed to better account for the spatial and temporal distributions of emissions. The BlueSky Framework, which was developed by the USDA Forest Service and US EPA, was used to develop the Asian biomass-burning emissions modeling system. The sub-models used for this study were the Fuel Characteristic Classification System (FCCS), CONSUME, and the Emissions Production Model (EPM). Our domain covers not only Asia but also Siberia and part of central Asia to assess the large boreal fires in the region. The MODIS fire products and vegetation map were used in this study. Using the developed modeling system, biomass-burning emissions were estimated during April and July 2008, and the results were compared with previous studies. Our results show good to fair agreement with those of GFEDv3 for most regions, ranging from 9.7 % in East Asia to 52% in Siberia. The SMOKE modeling system was combined with this system to generate three-dimensional model-ready emissions employing the fire-plume rise algorithm. This study suggests a practicable and maintainable methodology for supporting Asian air-quality modeling studies and to help understand the impact of air-pollutant emissions on Asian air quality.