• 한국지진공학회논문집
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• 제8권4호
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• pp.11-20
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• 2004

반응수정계수의 핵심구성요소인 연성계수를 토질조건에 따라 제시하였다. 47개의 지진에서 얻어진 총 1,860개의 지진기록이 사용되었으며, 지반 전단파의 평균속도에 따라 4가지의 토질조건을 고려하였다. 이러한 분류는 현재 사용되고 있는 UBC(1997), NEHRP(1997) 및 IBC 200(1997)의 토질조건과 일치한다. 통계적 회귀분석으로부터, 토질조건에 따른 연성계수를 평가하기 위한 단순화된 식이 제안되었다. 제안된 식은 상대적으로 간단하면서도 평균연성계수와 잘 일치하는 결과를 보였다. 제안된 식에 근거하여, 현재의 기준과 일치하는 토질조건에 따른 연성계수를 평가할 수 있을 것으로 기대한다

• 한국환경과학회지
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• 제13권5호
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• pp.479-488
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• 2004

Five sediment cores from the tidal flat of artificial Lake Shihwa are analyzed in terms of sedimentology and geochemistry to evaluate the heavy metal contamination and redox condition of surficial sediment following the Shihwa seawall construction. The variability of concentrations of various elements depends on the depositional environment, and reflects the various redox conditions and sediment provenances. The amounts of Ti and Al and their ratio of Ti/ Al with respect to Li clearly indicate that there is an anthropogenic contribution to the surficial sediment. The high concentrations of heavy metals suggest an anthropogenic contribution at ST. 34 and ST. 22. Concentrations of most elements (Cr, Cu, Zn and Pb) are higher near the Shihwa-Banwol industrial complex than in the central part of Lake Shihwa. Concentrations of heavy metal in surficial sediment near the Shihwa-Banwol industrial complex are two to eight times higher than in the center of Lake Shihwa. Enrichment factors (EF), which are normalized by the unpolluted shale, suggests a significant metallic contamination near the Shihwa-Banwol industrial complex (SBIC). The redox condition is divided into two anoxic and mixed oxi $c_oxic zones based on the carbon:sulfur (C/S) ratios of organic matter and elemental relationships. Correlations among geochemical elements Mn, U and Mo are significantly different from site to site, and may therefore be an indicator of the spatial redox condition. Controlling factors for switching anoxic/oxic conditions are thought to be water depth and the differences in industrial effluent supply. The variations of the Cu/Mn ratio in the sediments confirms above mentioned spatial differences of a redox condition in part, and therefore shows a location-dependence redox condition in sediments at four other sites. The redox condition of the surficial sediment characteristics of the Shihwa Lake are controlled by its geographic location and water depth.th.

• 한국건설관리학회논문집
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• 제11권5호
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• pp.75-83
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• 2010

건설산업은 노동집약적 산업으로 단위작업마다 작업자가 작업을 얼마나 효율적으로 수행했는가에 따라 노동생산성은 큰 영향을 받으며 노동생산성 향상을 위해 작업여건(work condition)이 관리되어야 한다. 작업여건은 자재, 장비, 타 작업간섭, 작업장 안전 등 작업자의 작업수행과정에 영향을 미치는 요소들로서, 작업의 특성에 따라 작업여건을 구성하는 요소들의 종류는 다양하다. 또한 작업여건들은 현장관리조직의 작업관리 행위 즉 작업관리방식에 의해 제어될 수 있다. 하지만 작업관리방식이 작업여건에 영향을 줄 수 있다는 것은 학계 및 산업차원에서 많은 사람들에게 인식되고 있지만 이를 정량적으로 검증하기 위한 노력은 부족하였다. 따라서 본 연구의 목적은 국내 건설현장에서 활용되고 있는 작업관리방식이 작업여건에 미치는 영향을 정량적으로 검증하는 것이다.

• 한국안전학회지
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• 제10권3호
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• pp.96-105
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• 1995

The better industry develops, the more spaces need but in the limited area. Most building become larger and more complicated if the more spaces need in the constant area. And this leads to do underground work in long period generally six(6) months for 6 basement stories due to the selection of TOP DOWN technique. Working environment in this underground area can be problems and should not be overlooked, because air quality in underground spaces become quickly worse. Recently, department name to control construction safety has been changed to ENVIRONMENT & SAFETY TEAM from SAFETY TEAM. This means that it is very important to control against environmental condition at site so much. Overall construction work as well as underground work should conform to the requirement of working environment, particularly against inhabitants around the construction area. Strut protection, one of earth protection method, in case to 40m long strut may become weaker due to thermal stress or its longitudinally compressive strain and the another one, earth anchor protection may not be applied to the site In case of encroaching on vertical underground borderline because of regulation to prohibit it. It is necessary that TOP DOWN technique should be introduced in order to solve the external and internal problem of the site such as difficulty level of the work, potential danger with excavating depth, and shortening workperiod. It is needed that improving way of working condition should be shown and simplified computer simulation program should be also provided for checking pollution level & ventilation, excluding of lighting problem here. Results measured with conformance to the Regulation for Working Environment Measurement, enforced by Ministry of Labor have been applied to the computer program developed here. Sample air taken at unit workplace which was considered as exposing condition of pollutant at breathing point and within a range of behavior of the workers, Identified exposing group in underground work, using Moded Flow Life Finally, three types of ventilation system, type I with blower & ventilator, type II natural supply with mechanical ventilation system, and type I mechanical ventilation with Drivent Fan Unit System are selected for this study.

• 대기
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• 제28권1호
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• pp.1-13
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• 2018

Characteristics of wind resources of offshore and coastal regions were compared using wind data obtained from HeMOSU-1 (Herald of Meteorological and Oceanographic Special Unit-1) meteorological mast located at Southwestern Sea, and ground-based LiDAR (Light Detection And Ranging) at Gochang observation site near it. The analysis includes comparison of basic wind statistics such as mean wind speed, wind direction, power law exponent and their temporal variability as well as site assessment items for the wind power plant such as turbulence intensity and wind power density at the two observation sites. It was found that the wind at HeMOSU-1 site has lower diurnal and seasonal variability than that at Gochang site, which lead to smaller turbulence intensity. Overall, the results of the comparative analysis show that the wind resource at HeMOSU-1 site located offshore has more favorable condition for wind power generation than the wind resource at Gochang which shows nature of coastal area.

• Journal of Astronomy and Space Sciences
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• 제27권4호
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• pp.337-343
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• 2010

Optical observation system provides angle-only measurement for orbit determination of space object. Range measurement can be directly acquired using laser ranging or tone ranging system. Initial orbit determination (IOD) by using angle- only data set shows discrepancy according to the measurement time interval. To solve this problem, range measurement data should be added for IOD. In this study, two-site optical observation was used to derive the range information. We have observed nine geostationary earth orbit satellites by using two-site optical observation system. The determination result of the range shows the accuracy over 99.5% compared to the results from the satellite tool kit simulation. And we confirmed that the orbit determination by the Herrick-Gibbs method with the range information obtained from the two-site observation is more accurate than the orbit determination by Gauss method with the one-site observation. For more accurate two-site optical observation, a baseline should satisfy an optimal condition of length and more precise observation system needed.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2008년도 추계 공동 국제학술대회
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• pp.675-679
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• 2008

본 연구에서 웹사이트 구축시 Ajax를 사용하는 경우가 기존의 경우에 비하여 얼마만큼의 효율성을 갖는지를 비교 분석하였다. 본 연구에서의 성능비교는, 실제로 사용되는 웹사이트의 가장 적합한 환경을 비교하기 위해 ASP를 이용한 기존의 웹사이트 모델과 ASP.NET Ajax를 이용한 웹사이트를 같은 조건에서의 샘플사이트를 구축하여 비교 분석하였다. 두 사이트 모델의 각각에 데이터를 생성, 수정, 삭제, 질의 시의 응답속도 등을 비교 분석하였다. 실험을 통한 비교 분석 결과로 기존의 웹사이트 모델보다 Ajax를 이용한 모델의 응답속도가 향상된 것으로 나타났다.

• 한국지진공학회논문집
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• 제20권4호
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• pp.257-268
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• 2016

In the companion papers (I, II), site-specific response analyses were performed at more than 300 domestic sites and a new site classification system and design response spectra (DRS) were proposed using the results of the site-specific response analyses. In this paper, the proposed site classification system and the design response spectra are compared with those in other seismic codes and verified by different methods. Firstly, the design response spectra are compared with the design response spectra in Eurocode 8, KBC 2016 and MOCT 1997 to estimate quantitative differences and general trends. Secondly, site-specific response analyses are carried out using $V_S$-profiles obtained using field seismic tests and the results are compared with the proposed DRS in order to reduce the uncertainty in using the SPT-N value in site-specific response analyses in the companion paper (I). In addition, site coefficients from real earthquake records measured in Korean peninsula are used to compare with the proposed site coefficients. Finally, dynamic centrifuge tests are also performed to simulate the representative Korean site conditions, such as shallow depth to bedrock and short-period amplification characteristics. The overall results showed that the proposed site classification system and design response spectra reasonably represented the site amplification characteristic of shallow bedrock condition in Korea.

• Spatial Information Research
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• 제13권3호
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• pp.323-333
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• 2005

본 연구는 ICAO 기준과 지리정보를 이용한 공항입지선정에 관한 연구이다. 우리나라는 백두대간을 중심으로 전국토의 $70\%$이상이 산악지형이기 때문에 동서방향의 원활한 물류시스템이 구축되어있지 않고 있다. 현재 국제민간항공기구와 미국연방항공국 기준에 따라 공항입지선정을 하기 때문에 산악지형이 많은 우리나라에 여건에 맞는 기준마련이 절실하다. 본 연구에서는 국제민간항공기구와 미국연방항공국 기준으로 울진공항의 지리학적 위치, 기상, 인구현황, 교통현황에 따른 항공수요 및 지상교통수요에 관한 분석을 실시하고자 한다. 울진공항의 지리학적 위치, 기상, 인구현황, 교통현황에 따른 항공수요 및 지상교통수요에 관한 분석을 실시한 후 공역조건에 따른 지형학적인 위험요소를 검토하였다. 연구결과 기존의 공군 비상활주로를 이용한 기성 후보지는 농어촌 도로와 해안도로를 연결하는 지방도가 위치하는 것으로 나타났으며 공역분석에서 공항 후보지 검토결과 기성 후보지가 타 후보지 보다 양호한 것으로 나타났다.

• 한국안전학회지
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• 제10권4호
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• pp.87-96
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• 1995

It is only three(3) years since we applied brackets for scaffolding in the construction area. Unfortunately, there is no structural criteria on how to install those in the site so far, despite the fact that those brackets have been applied into the site by the firms already. It is shown that resistant capacity of each bracket type has been investigated, analyzed from this experimental study. Accident-concerning data on construction site analyzed by the Ministry of Labor, show temporary structure involves 18.6% of the total industrial accident, which the accidents from scafold-supporting brackets have rate of 42.5% of the ones occurred from the temporary structures. There are two main aspects to be observed : one is how much resistant capacity the brackets have themselves, the other is how exactly to install those without eccentricity. But practically, nobody does check of this bolt-installing conditions in the site and no check of tightening level of nut because there is no available tool to check torque amount for this kind of nut. We just have to rely on scaffolders experience of this tightening. This experiment involves just this variable of tightness at site. Eventually this insufficient tightness causes to collapse those scaffolding structures. The bracket might have less the one than its original capacity due to this insufficient tightness. Three(3) times of PIVOT tests show that fractured condition of two(2) row brackets has occurred mostly at lower bolt due to shear force. Therefore, tightness of bracket-installing bolt, tensile strength of the bolt, shear strength of the bolt, loading condition with equal two point or inequal two point loads, are mainly investigated as variables in this study.