• Title/Summary/Keyword: Dongcheon

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An Eight-directional Airborne Chloride Collection Method for the Application of an Appropriate Anti-corrosive Material for Each Side of a Building

  • Cho, Gyuhwan;Yeo, Inhwan;Park, Dongcheon
    • Architectural research
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    • v.18 no.2
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    • pp.75-82
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    • 2016
  • To secure the anticorrosive performance of structures in the oceanic environment it is necessary to select appropriate finishing materials and thickness of cover. However, airborne chloride deposition varies depending on the collector used, and it is difficult to select appropriate finishing materials. For this reason, an eight-directional collector is proposed in this study through reviewing the differences between existing airborne chloride collectors and the new one. To analyze airborne chloride deposition according to the direction from which it flows and verify the performance of the collector proposed in this study, airborne chlorides were deposited on the collector for one year at five different locations in an oceanic environment. From the experiment, it was verified that in terms of direction, there were differences in airborne chloride deposition of up to more than 1.5 times. Based on these research findings, the anti-corrosive method applied can be different for each side of a building's structure, and this is believed to serve as an effective and systemic chloride resistance design.

Performance Evaluation of MACSec for Host Mobility (MACSec의 단말 이동성 성능평가)

  • Ahn, Sangjun;Shin, Dongcheon
    • The Journal of Society for e-Business Studies
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    • v.24 no.2
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    • pp.55-70
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    • 2019
  • It is essential to consider the relationships between each component in the communication infrastructure in order to build and optimize the infrastructure. In this paper, based on the major factors to consider for the optimized communication infrastructure, we propose an enhanced MACSec-based deployment mechanism for communication infrastructure. The proposed MACSec mechanism can replace the IPSec without the additional devices and redesign of the communication infrastructure. In addition, we evaluate the performance of MACSec and IPSec in terms of the major factors such as message overhead, encryption processing, and host mobility. According to the evaluation results, we can say that MACSec is superior to IPSec with regard to mobility as well as hop delay and message overhead.

2-D Inundation Analysis According to Post-Spacing Density of DEMs from LiDAR Using GIS (GIS를 활용한 LiDAR 자료의 밀도에 따른 2차원 침수해석)

  • Ha, Chang-Yong;Han, Kun-Yeun;Cho, Wan-Hee
    • Journal of the Korean Association of Geographic Information Studies
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    • v.13 no.1
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    • pp.74-88
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    • 2010
  • In this study, the points of LiDAR were modified in order to generate various DEM resolutions by applying LiDAR data in Ulsan. Since the LiDAR data have points with 1m intervals, the number of points for each resolution was modified to the size of 1, 5, 10, 30, 50, 100m by uniformly eliminating the points. A runoff analysis was performed on Taehwa river and its tributary, Dongcheon, with 200 year rainfall exceedance probability. 2-dimensional inundation analysis was performed based on the density of LiDAR data using FLUMEN, which was used to establish domestic flood risk map. Once DEM data obtained from LiDAR survey are used, it is expected that the study results can be used as data in determining optimal grid spacing, which is economical, effective and accurate in establishing flood defence plans including the creation of flood risk map.

The Flow Variation due to Pier Construction at Kwangyang Bay (컨테이너 부두건설에 따른 광양만의 유황변동)

  • Choi, Song Yeol;Cho, Won Cheol;Lee, Won Hwan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.12 no.3
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    • pp.115-125
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    • 1992
  • The variation of flow pattern caused by the topographical change of Kwangyang bay, is analyzed using the numerical tidal model for the depth-integrated two- dimensional long wave equation. The results of study are as follows. Due to pier construction, the area of water surface is deceased and the water inflow into the Kwangyang bay is reduced. For this result, at the outer bay of Myo island, the tidal range is slightly increased. And at the inner bay, water level is dropped generally, and especially at the time of low water tide, the phenomena of water level drop obviously appears. According to the variation pattern, flow velocities is lower than those of non-construction condition over the Kwangyang bay. But at the channel(from Kwangyang east stream) flowing into the east Kwangyang bay, for the contraction of channel profile, flow velocity is increased. The study based on the 100 year frequency design flood discharge from Sueocheon(river) and Dongcheon(river) which are flowing into the bay and Seomjin River flowing along the boundary of the bay is also performed. During the spring tide condition, the results showed the rise of water level about 1.2 m at Seomjin River Estuary and 0.3 m at inner bay is occurred.

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Rock Weathering Characteristics of the Stone Buddha statue in the Gulbulsa temple site at Mt. Sogeumgang in Gyeongju-Si, Southeastern Korea (경주시 소금강산 굴불사지석불상의 풍화 특성)

  • Yoon, Soon-Ock;Park, Kyunggeun;Hwang, Sangill
    • Journal of the Korean Geographical Society
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    • v.47 no.6
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    • pp.809-824
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    • 2012
  • Stone cultural heritages quantitatively as well as qualitatively occupy a large proportion in the designated heritages in Korea. The Stone Buddha statue in the Gulbulsa temple site, designated as the No. 121 treasure in 1935, is located in the southwestern slope of Mt. Sogeumgang, Dongcheon-dong, Gyeongju-si, Gyeongbuk Province and Buddhist images are sculptured on four sides of a 3.5m-tall gigantic rock. The damage states result from the weathering degree and indicate high correlation with the water contents. The water contents in the Stone Buddha of Gulbulsa temple site are highest at the east side and then decrease in order of north, south and west sides. These are proportional to the durations of sunshine. Moreover, the Stone Buddha of Gulbulsa temple site with dense joints, repaired areas and vegetated areas by lichens shows high water contents and damage states.

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Spear-phishing Mail Filtering Security Analysis : Focusing on Corporate Mail Hosting Services (스피어피싱 메일 필터링 보안 기능 분석 : 기업메일 호스팅 서비스 중심으로)

  • Shin, Dongcheon;Yum, Dayun
    • Convergence Security Journal
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    • v.20 no.3
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    • pp.61-69
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    • 2020
  • Since spear-phishing mail attacks focus on a particular target persistently to collect and take advantage of information, it can incur severe damage to the target as a part of the intelligent and new attacks such as APT attacks and social engineering attacks. The usual spam filtering services can have limits in countering spear-phishing mail attacks because of different targets, goals, and methods. In this paper, we analyze mail security services of several enterprises hosted by midium and small-sized enterprises with relatively security vulnerabilities in order to see whether their services can effectively respond spear-phishing mail attacks. According to the analysis result, we can say that most of mail security hosting services lack in responding spear-phishing mail attacks by providing functions for mainly managing mails including spam mail. The analysis result can be used as basic data to extract the effective and systematic countermeasure.

An Analysis of Articles for Health Promotion Behaviors of Korean Middle-Aged (국내 중년의 건강증진에 대한 선행연구 분석)

  • Kang, Young-Sil;Chung, Mi-Ja;Park, Yong-Sook;Lee, Yeong-Sook;Kim, Hyang-Sook;Lee, Dong-Mae;Lee, Dong-Won
    • Research in Community and Public Health Nursing
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    • v.20 no.1
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    • pp.75-86
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    • 2009
  • Purpose: This study has a purpose to suggest research and intervention directions for health promoting behaviors (HPB) of the Korean middle-aged in the future. Methods: Forty four articles on HPB of the Korean middle-aged were reviewed and analyzed. The articles analyzed are theses written for a doctoral or master's degree and published between 1995 and 2007. Results: 1. As for the major characteristics of the subject groups, most of them were between 40 and 60 years old (61.4%), were females (79.5%), and resided in cities (84.1%). 2. The dependent variables adopted were physiological, psychological and cognitive factors (self-efficacy, knowledge of health management, etc.), HPB and factors related to Health Promoting Lifestyle Profile (HPLP). 3. The average scores of HPLP were $1.57{\sim}3.08$ on a 4-point scale. The highest score was observed in self-actualization, and the lowest score in exercise. 4. Self-efficacy, perceived health status and income had significant correlations with HPB. 5. In regression analysis, self-efficacy, self-esteem and perceived health status were the most powerful predictors. Conclusion: It is necessary to develop intervention tools for more diverse HPB of the Korean middle-aged. The interventions are recommended to focus on increasing exercise and to use strategies for improving self-efficacy and self-esteem.

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Proper Arrangement of City Park though Analysis of Disposition Distance (유치거리 분석을 통한 도시공원의 적정배치에 관한 연구)

  • Ryu, Yeun-Soo;Ra, Jung-Hwa;Do, Hu-Jo
    • Current Research on Agriculture and Life Sciences
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    • v.20
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    • pp.33-38
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    • 2002
  • The purpose of this study is to analysis of disposition distance of city park for the plan of suitable arrangement of city park based on the date examining Daegu Metropolitan City. The results of this study are as follows. 1) The result of analysis of population density as the case of districts, it appeared highly in city center area which Seo-Gu district and Nam-Gu district besides Jung-Gu district. However, it apperared in a low Buk-Gu district, Dong-Gu district and Salseong-Gun. 2) The result of analysis of population density as the case of regions, it appeared very highly Joukjun-Dong of Dalseo-Gu district($31,554per/km^2$), Naedang-Dong of Seo-Gu district($29,922per/km^2$). However it appeared in a low Yeuga-Maen($85per/km^2$) and Gachang-Maen($94per/km^2$) of Dalseong-Gun. The regions where the population density is high have very low green space and live a lot of low income layer. 3) The result of analysis of disposition distance, in the case of children park, it appeared an intensive distribution in Dongcheon-Dong and Guam-Dong of Buk-Gu district, Whanggm-Dong and Dusan-Dong of Suseong-Gu district, Sangin-Dong and Yeongsan-Dong and Walsung-Dong of Dalseo-Gu district. however, it appeared in a low in Jung-Gu district. The case of urban park of the neighboring area, it appeared the most in Dalseo-Gu district except 2 parks in Jung-Gu district, the case of urban park of the walking area, it appeared in equality in city. 4) In conclusion, the area have high population density and lots of low income layer, is in out of disposition distance should be considered in first for city park plan.

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A Risk Assessment Scheme of Social Engineering Attacks for Enterprise Organizations (사회공학 공격에 대한 기업조직의 위험 수준 평가 방안)

  • Park, Younghoo;Shin, Dongcheon
    • Convergence Security Journal
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    • v.19 no.1
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    • pp.103-110
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    • 2019
  • Recently security related attacks occur in very diverse ways, aiming at people who operate the system rather than the system itself by exploiting vulnerabilities of the system. However, to the our best knowledge, there has been very few works to analyze and strategically to deal with the risks of social engineering attacks targeting people. In this paper, in order to access risks of social engineering attacks we analyze those attacks in terms of attack routes, attack means, attack steps, attack tools, attack goals. Then, with the purpose of accessing the organizational risks we consider the characteristics and environments of the organizations because the impacts of attacks on the organizations obviously depend on the characteristics and environments of the organizations. In addition, we analyze general attack risk assessment methods such as CVSS, CWSS, and OWASP Risk Rating Methodolog. Finally, we propose the risk access scheme of social engineering attacks for the organizations. The proposed scheme allows each organization to take its own proper actions to address social engineering attacks according to the changes of its environments.

Estimation of flood in Suncheon Dongcheon watershed using dynamic water resources assessment Tool (동적수자원평가모형을 이용한 순천동천 유역의 홍수량 산정)

  • Kim, Deokhwan;Kim, Hyeonjun;Jang, Cheolhee
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.285-285
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    • 2022
  • 기후변화가 현실화되면서 수자원평가 (Water Resources Assessment)에 대한 관심과 중요성이 높아지고 있다. 본 연구에서는 '주민공감 문제기획리빙랩' 대상지인 순천은 동천을 중심으로 홍수량을 정량적으로 분석하였다. 순천시의 가장 시급한 사안 중 하나인 범람 및 침수 문제로, 최근 3년(2018~2020)간의 집중호우로 인한 내수배제로 주택 및 도로침수, 산사태 등의 피해를 겪었다. 시기마다 고질적으로 반복되는 동천 인근 지역의 침수문제를 사전에 예방하고 피해의 빈도나 규모를 줄이기 위하여 분석을 수행하였다. 이에 본 연구에서는 환경부의 지원을 받아 한강홍수통제소와 한국건설기술연구원이 공동으로 개발한 동적수자원평가모형(DWAT, Dynamic Water Resources Assessment Tool)을 이용하여 정량적으로 홍수량 산정을 하고자 한다. 본 모형은 전 세계가 무료로 이용할 수 있는 수자원평가도구로 사용자의 편의를 위해 GIS전처리 기능을 포함하고 있어, 자동으로 유역 매개변수 및 면적 평균강우량을 Thiessen method를 사용하여 산정할 수 있다. 또한, 물의 순환과정을 투수 및 불투수지역으로 구분되며, 투수지역은 1개의 토양층과 1개의 불압대수층으로 구성되고, 유출기여역과 함양역으로 유역을 분할하여 적용할 수 있으며, 대수층을 통하여 지하수의 흐름을 산정할 수 있다. 기상청에서 제공하는 기상자료를 분석하여 과거 관측 강우사상 3개를 선정하여 검·보정을 수행하였으며, 그 결과 모형 효율계수(Nash-Sutcliffe efficiency) 및 결정계수(Coefficient of Determination)가 0.78~0.94, 0.82~0.94로 우수한 모의 결과를 산정할 수 있었다. 빈도별 확률강우량을 Huff 4분위법을 사용하여 확률홍수량을 산정하였다. 미래 홍수량 증감량 산정을 위하여 RCP(Representative Concentration Pathways) 기후변화 시나리오를 사용하였다. 관측값과 모의값의 누적확률분포 이용하여 모의값의 확률분포를 관측값의 확률분포에 사상시키는 방법인 분위사상법(Quantile Mapping)을 사용하여 시나리오자료를 보정하였다. 본 연구에서 산정한 홍수량을 바탕으로 침수피해를 막기 위한 구조적 및 비구조적 방안을 위한 기초자료로 사용될 것으로 판단된다.

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