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SPATIAL DISTRIBUTION OF STARS AROUND SIX METAL-POOR GLOBULAR CLUSTERS IN THE GALACTIC BULGE
장초롱,김재우,Noriyuki Matsunaga,한미화,고종완,천상현,강민희,손영종 한국천문학회 2013 Journal of The Korean Astronomical Society Vol.46 No.6
Wide-field $JHK_s$ images obtained with the SIRIUS near-infrared camera of the IRSF 1.4m telescope are used to examine the tidal structures of the spatial stellar configuration around six metal-poor ([Fe/H]$<-1.0$) globular clusters located within 3 kpc from the Galactic center. The radial surface density profiles are obtained from the surface photometry of the cluster images and the star counting for the photometric data. For the star counting, candidates of cluster member stars are selected with an filtering algorithm in color-magnitude diagrams. We find that the six target clusters show tidal overdensity features in the radial surface density profiles. There is a break inside the tidal radius for each cluster, and the profile in the outer overdensity region is characterized by a power law. Two-dimensional density maps of all the clusters show distorted asymmetric stellar configurations in the outer region. In five out of the six target clusters, the overdensity features are likely to be associated with the effects of the Galaxy dynamical interaction and the cluster space motions. The observed tidal configurations of stars suggest that several metal-poor clusters in the Galactic bulge are possibly surviving remnants of mergers to build the old stellar system of the Galactic bulge.
LWE와 LWR을 이용한 효율적인 다중 비트 암호화 기법
장초롱,서민혜,박종환 한국정보보호학회 2018 정보보호학회논문지 Vol.28 No.6
Recent advances in quantum computer development have raised the issue of the security of RSA and elliptic curvecryptography, which are widely used. In response, the National Institute of Standards and Technology(NIST) is working onthe standardization of public key cryptosystem which is secure in the quantum computing environment. Lattice-basedcryptography is a typical post-quantum cryptography(PQC), and various lattice-based cryptographic schemes have beenproposed for NIST’s PQC standardization contest. Among them, EMBLEM proposed a new multi-bit encryption methodwhich is more intuitive and efficient for encryption and decryption phases than the existing LWE-based encryption schemes. In this paper, we propose a multi-bit encryption scheme with improved efficiency using LWR assumption. In addition, weprove the security of our schemes and analyze the efficiency by comparing with EMBLEM and R.EMBLEM. 최근 양자 컴퓨터에 대한 개발이 활발히 진행되면서, 기존에 널리 사용되고 있는 RSA와 타원곡선 암호 알고리즘의 안전성에 대한 문제가 제기되고 있다. 이에 대응하기 위하여 미국 표준기술연구원(NIST)은 양자 컴퓨팅 환경에서도 안전한 공개키 암호 기법에 대한 표준화 작업을 진행하고 있다. 대표적인 포스트 양자 암호(post-quantumcryptography, PQC) 기법으로는 격자기반 암호(lattice-based cryptography)가 있으며, NIST의 PQC 표준화 공모에도 다양한 격자기반 암호 기법들이 제안되었다. 이 중 EMBLEM은 기존의 LWE (learning witherrors) 가정을 기반으로 하여 설계된 암호 기법들과는 달리, 더 직관적이고 효율적으로 암/복호화가 가능한 새로운다중 비트 암호화 방법을 제안하였다. 본 논문에서는 LWR(learning with rounding) 가정을 추가적으로 사용하여 더 효율적으로 동작하는 다중 비트 암호화 기법을 제안한다. 그리고 제안하는 기법의 안전성을 증명하고,EMBLEM 및 R.EMBLEM과의 비교를 통해 효율성을 분석한다.
서울시 화재 취약 권역 분석 및 재조정 방안 연구 -서울시 중구를 대상으로-
장경은(Jang, Kyung-Eun),정유미(Jung, Uemee),박초롱(Park, Chorong),손동욱(Sohn, Dong-Wook) 한국생태환경건축학회 2021 한국생태환경건축학회 학술발표대회 논문집 Vol.21 No.2
In the case of a fire in the city center where population and buildings are dense, the risk of a social disaster increases. In order to find concrete solutions to prepare for this, it is necessary to analyze the spatial scope. Accordingly, using GIS for Jung-gu, Seoul, which has a high population density, the population vulnerable to disasters, the ratio of old buildings, and the density of fires were derived, and the areas excluded from the fire service area through network analysis were analyzed for each administrative dong to determine the final fire-vulnerable area. Therefore, based on the analysis results, a plan for readjustment of areas that can prepare for disasters according to social, physical, and regional characteristics was studied.
기후변화 종합 취약성 분석을 통한 재해 관리 강화방안 - 서울시를 중심으로 -
장경은,손동욱,박초롱,이종호 한국생태환경건축학회 2023 한국생태환경건축학회 논문집 Vol.23 No.3
Purpose: Currently, various social problems caused by urbanization are intensifying. Not only domestically, but also the importance of responding to global climate change is growing. Climate change causes natural disasters and causes human and property damage. According to the 2020 Disaster Yearbook presented by the Ministry of Public Administration and Security, the damage caused by natural disasters is steadily increasing from 2010 to 2020. Therefore, the purpose of this study is to present in-depth countermeasures by deriving vulnerability characteristics for each disaster through disaster-specific vulnerability analysis. Method: This study utilized Arc GIS Pro, which can perform spatial and quantitative analysis for vulnerability analysis. First, data of different units was standardized, and based on this, numerical data was constructed and Raster Data analysis technique was used. Second, based on the results of vulnerability analysis by spatial disaster, the VRI formula was used to select autonomous districts vulnerable to disasters. Thirdly, an in-depth response strengthening plan was suggested through a review of climate change adaptation measures in areas with high vulnerability. Result: The range of disasters with high vulnerability was derived according to the social, economic, environmental, and physical conditions of each district in Seoul. In-depth regional response plans were additionally suggested by reviewing the existing measures to respond to heat waves, floods, fine dust, and cold waves by region. Physical infrastructure expansion plans such as regional heat shelters, flood shelters, fine dust shelters, and cold wave shelters were proposed, and response measures such as strengthening disaster publicity and strengthening the notification system were presented as human response measures.
Near-IR TRGB Distance Modulus of Dwarf Irregular Galaxy IC 1613
정미영,천상현,장초롱,한미화,임동욱,한원용,손영종 한국우주과학회 2009 Journal of Astronomy and Space Sciences Vol.26 No.4
The JHK_S magnitudes of the red giant branch tip (TRGB) and the distance moduli of the nearby dwarf irregular galaxy IC 1613 have been determined from the nearinfrared luminosity functions (LFs) of the resolved stars in the galaxy. Applying a Savitzky-Golay filtering, we derived the second derivatives of the LFs, and estimated the apparent magnitudes of the TRGB as mJ = 19:1, mH = 18.4, and mKs = 18.0. The mean values of the theoretical absolute magnitudes of the TRGB were measured by using the Yonsei-Yale isochrones with a metallicity range of -2.1 < [Fe/H] < -0.5 and age of 12 Gyr. The derived values of near-infrared TRGB distance moduli for IC 1613 are (m-M) = 24.12 ± 0:25, 24.20 ± 0.44, and 24.00 ± 0.52 for J,H, and Ks bands, respectively. The JHK_S magnitudes of the red giant branch tip (TRGB) and the distance moduli of the nearby dwarf irregular galaxy IC 1613 have been determined from the nearinfrared luminosity functions (LFs) of the resolved stars in the galaxy. Applying a Savitzky-Golay filtering, we derived the second derivatives of the LFs, and estimated the apparent magnitudes of the TRGB as mJ = 19:1, mH = 18.4, and mKs = 18.0. The mean values of the theoretical absolute magnitudes of the TRGB were measured by using the Yonsei-Yale isochrones with a metallicity range of -2.1 < [Fe/H] < -0.5 and age of 12 Gyr. The derived values of near-infrared TRGB distance moduli for IC 1613 are (m-M) = 24.12 ± 0:25, 24.20 ± 0.44, and 24.00 ± 0.52 for J,H, and Ks bands, respectively.