• 한국환경복원기술학회지
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• 제18권6호
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• pp.227-237
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• 2015

From January 2013 to October 2015, weed invasion control techniques was tested in the test road of Jungbunaeryuk expressway so as to collect preliminary data for the management methods of the upper exterior banking of expressway shoulders. Then, monitoring was conducted and its results are as follows. Mat (sheet), solidifying agent, and mulching (wood chips) were applied for the test and their initial effects of preventing weed invasion were all excellent. It was found that the homogeneity of the wood chip mulching method needs to improve. In the mat method and the mulching method were found to have the most excellent economic feasibility and aesthetics, respectively. The covering degree was found to be the highest at 80% in the control site, followed by the wood chip site at 20% and the solidifying agent site and the non-woven fabric site at 5% each. As for species diversity, the control had the largest variety of species. Two years after the construction, many different species of plants invaded and were growing. Plants including weed didn't tend to invade the slopes applied with non-woven fabric. In addition, weed didn't invade the solidifying agent site and the aesthetics of the upper exterior banking of expressway shoulders was found to be excellent. The wood chip site was found to require consistent management for preventing weed invasion. The mat (sheet) site, the solidifying agent site, and the wood chip mulching site were found to have excellent weed prevention effects. As time passed, the mat (sheet) site and the solidifying agent site showed better weed prevention effects. However, they need consistent monitoring for further application.

• Journal of Ecology and Environment
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• 제40권1호
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• pp.75-83
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• 2016

Background: In order to evaluate the effect of pH, known as a critical factor for shaping the biogeographical microbial patterns in the studies by others, on the bacterial diversity, we selected two sites in a similar geographical location (site 1; north latitude 35.3, longitude 127.8, site 2; north latitude 35.2, longitude 129.2) and compared their soil bacterial diversity between them. The mountain soil at site 1 (Jiri National Park) represented naturally acidic but almost pollution free (pH 5.2) and that at site 2 was neutral but exposed to the pollutants due to the suburban location of a big city (pH 7.7). Methods: Metagenomic DNAs from soil bacteria were extracted and amplified by PCR with 27F/518R primers and pyrosequenced using Roche 454 GS FLX Titanium. Results: Bacterial phyla retrieved from the soil at site 1 were more diverse than those at site 2, and their bacterial compositions were quite different: Almost half of the phyla at site 1 were Proteobacteria (49 %), and the remaining phyla were attributed to 10 other phyla. By contrast, in the soil at site 2, four main phyla (Actinobacteria, Bacteroidetes, Proteobacteria, and Cyanobacteria) composed 94 %; the remainder was attributed to two other phyla. Furthermore, when bacterial composition was examined on the order level, only two Burkholderiales and Rhizobiales were found at both sites. So depending on pH, the bacterial community in soil at site 1 differed from that at site 2, and although the acidic soil of site 1 represented a non-optimal pH for bacterial growth, the bacterial diversity, evenness, and richness at this site were higher than those found in the neutral pH soil at site 2. Conclusions: These results and the indices regarding diversity, richness, and evenness examined in this study indicate that pH alone might not play a main role for bacterial diversity in soil.

• 한국안전학회지
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• 제35권2호
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• pp.76-83
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• 2020

This study examined the effects of perceptual differences of safety leadership between managers and workers on workers' safety attitudes and behavior in two construction sites. In addition, the mediating role of safety attitude between safety leadership and safety behavior across discrepancy level of safety leadership. This study was conducted on two first-tier construction companies within the 100th place in 2019. Two companies were similar in size(100 - 150 billion won) and process from the basement frame finishing stage to start of the ground structure of apartment. In A Site, 40 managers and 73 workers, 42 managers and 77 workers in B site participated the survey on managers' safety leadership, and workers' safety attitude and behavior. The results showed that there was no significant difference between the safety leadership scores assessed by the manager and workers at site B. However, the safety leadership scores assessed by the managers were significantly higher than that by the workers at site A. The workers' safety attitudes and behaviors at site B were higher than those of workers at site A. Moreover, Site B was significantly higher in the effects of safety leadership on safety behavior than Site A. At site B, safety leadership had a significant influence on safety behavior even after controlling the safety attitude of workers. At site A, safety leadership had no significant effect on safety behavior after controlling safety attitude. These findings suggest that there is managers' self-serving bias on safety leadership in site A and that this bias of leadership can negatively affect workers' safety attitude and behaviors. In addition, it can be seen that if the self-serving bias on safety leadership occurs, the manager's safety leadership has less influence on workers' safety behavior.

• 한국지진공학회논문집
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• 제10권2호
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• pp.63-71
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• 2006

동반논문(II-지반분류 개선방법)에서는 지반의 고유주기를 기준으로 지반을 분류하는 방법이 국내 지반조건에 적합한 지반분류 방법으로 제시하였다. 그러나, 지반분류 방법을 개선하여도 해석결과의 평균 스펙트럼 가속도 값과 재산정된 응답스펙트럼과 차이가 나타나는 부분이 존재한다. 이는 설계응답스펙트럼을 작성에 필요한 증폭계수를 계산하는 방법을 변경해야 해결할 수 있다. 본 논문에서는 국내 지반조건에 적합하도록 증폭계수를 재산정하기 위한 적분구간 변경에 대하여 검토하였다. 검토 결과 장주기 영역의 증폭계수 $F_v$의 적분구간은 현재 주기 0.4초${\sim}$2.0초에서 주기 0.4초${\sim}$1.5초로 변경할 경우 해석결과의 평균 스펙트럼 가속도 값과 설계응답스펙트럼이 비교적 잘 일치하는 결과를 얻을 수 있었고, 기존의 방법보다 국내 지반특성에 더 적합한 설계응답스펙트럼을 작성할 수 있었다.

• Earthquakes and Structures
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• 제17권6호
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• pp.557-566
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• 2019

The evaluation of the seismic hazard for a given site is to estimate the seismic ground motion at the surface. This is the result of the combination of the action of the seismic source, which generates seismic waves, the propagation of these waves between the source and the site, and site local conditions. The aim of this work is to evaluate the sensitivity of dynamic response of extended structures to spatial variable ground motions (SVGM). All factors of spatial variability of ground motion are considered, especially local site effect. In this paper, a method is presented to simulate spatially varying earthquake ground motions. The scheme for generating spatially varying ground motions is established for spatial locations on the ground surface with varying site conditions. In this proposed method, two steps are necessary. Firstly, the base rock motions are assumed to have the same intensity and are modelled with a filtered Tajimi-Kanai power spectral density function. An empirical coherency loss model is used to define spatial variable seismic ground motions at the base rock. In the second step, power spectral density function of ground motion on surface is derived by considering site amplification effect based on the one dimensional seismic wave propagation theory. Several dynamics analysis of a curved viaduct to various cases of spatially varying seismic ground motions are performed. For comparison, responses to uniform ground motion, to spatial ground motions without considering local site effect, to spatial ground motions with considering coherency loss, phase delay and local site effects are also calculated. The results showed that the generated seismic signals are strongly conditioned by the local site effect. In the same sense, the dynamic response of the viaduct is very sensitive of the variation of local geological conditions of the site. The effect of neglecting local site effect in dynamic analysis gives rise to a significant underestimation of the seismic demand of the structure.

• 한국물환경학회지
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• 제25권3호
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• pp.452-458
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• 2009

This study was carried out to assess the effect of discharge loading at sewage treatment plants (STP) on water quality in Kyoungan stream. The seasonal variations of water quality (BOD, COD, SS, TN, and chl.a) at site 1(Mesanribo) were similar with those at site 2(Sehabo). BOD, COD, SS, and chl.a concentration were also similar except for TN and TP concentration which were lower than those at site 1. The BOD, COD, TN, TP and chl.a concentration at site 2 in dry period were higher than that of wet period. The ratios of BOD, TP, COD, SS discharge loading at all STP in Kyoungan stream watershed to delivery loading at site 2 were 0.69, 0.54, 0.48, 0.31, and 0.26 on average, respectively. Both site 1 and site 2, the seasonal variations of discharge loading at STP did not showed any relationship with those of water quality. The mean ratios of inflow loading at site 1 to delivery loading at site 2 were relatively high that ranged from 0.43 to 0.61. In dry period, the ratios of discharge loading at STP in Sehabo watershed to delivery loading at site 2 were below 0.2 except for BOD (0.24), and decreased <0.1 in wet period. While, SS loading from watershed between site 1 and site 2 to delivery loading at site 2 ratios increased in wet period.

• 한국산림과학회지
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• 제96권3호
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• pp.300-306
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• 2007

본 연구는 산지사면에 시공되어 있는 사방댐내의 퇴사량에 영향을 미치는 산림환경 및 하천형태학적 인자를 분석하고 수량화이론(I)을 이용하여 예방적인 측면에서 사방댐의 시공 적지를 선정하고 예측하였다. 각 인자의 category별 상대점수를 262개 사방댐의 각종 인자에 반응시켜 사방댐의 시공적지를 예측할 수 있는 판정표를 개발하였고 또한 판정표를 이용하여 시공적지를 I급지(Very suitable site), II급지(Suitable site), III급지(Poor suitable site)로 구분하였다. 따라서 각종 산지재해로부터 예방적인 차원의 사방사업인 사방댐을 건설하고자 할 때 객관적인 지표가 될 수 있는 판정표를 이용하여 시공에 따른 타당성과 시공적지를 예측함으로서 주관적 판단에 의한 불합리성과 시공 후 적지로 판정되지 못할 경우 발생하는 막대한 예산낭비를 막을 수 있고 사방댐에 의한 토사조절을 극대화함으로서 산지사면에서 발생하는 각종 재해에 대한 피해를 최소화할 수 있어 산림유역 관리에 많은 기여를 할 수 있을 것으로 사료된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권2_spc호
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• pp.28-54
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• 2020

Even though a systematic sampling approach is very crucial in both the general and detailed investigation phases to produce the best conceptual site model for contaminated sites, the concept is not yet established in South Korea. The U.S. Environmental Protection Agency (EPA) issued the 'Strategic Sampling Approaches Technical guide' in 2018 to help environmental professionals choose which sampling approaches may be needed and most effective for given site conditions. The EPA guide broadly defines strategic sampling as the application of focused data collection across targeted areas of the conceptual site model (CSM) to provide the appropriate amount and type of information needed for decision-making. These strategic sampling approaches can prevent the essential data from missing, minimize the uncertainty of projects and secure the data which are necessary for the important site-decisions. Furthermore, these provide collaborative data sets through the life cycle phases of projects, which can generate more positive proofs on the site-decisions. The strategic sampling approaches can be divided by site conditions. This technical guide categorized it into eight conditions; High-resolution site characterization in unconsolidated environments, High-resolution site characterization in fractured sedimentary rock environments, Incremental sampling, Contaminant source definition, Passive groundwater sampling, Passive sampling for surface water and sediment, Groundwater to surface water interaction, and Vapor intrusion. This commentary paper introduces specific sampling methods based on site conditions when the strategic sampling approaches are applied.

• Earthquakes and Structures
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• 제15권1호
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• pp.1-8
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• 2018

A new site classification system and site coefficients based on local site conditions in Korea were developed and implemented as a part of minimum design load requirements for general seismic design. The new site classification system adopted bedrock depth and average shear wave velocity of soil above the bedrock as parameters for site classification. These code provisions were passed through a public hearing process before it was enacted. The public hearing process recommended to modify the naming of site classes and adjust the amplification factors so that the level of short-period amplification is suitable for economical seismic design. In this paper, the new code provisions were assessed using dynamic centrifuge tests and by comparing the design response spectra (DRS) with records from 2016 Gyeongju earthquake, the largest earthquake in history of instrumental seismic observation in Korea. The dynamic centrifuge tests were performed to simulate the representative Korean site conditions, such as shallow depth to bedrock and short-period amplification characteristics, and the results corroborated with the new DRS. The Gyeongju earthquake records also showed good agreement with the DRS. In summary, the new code provisions are reliable for representing the site amplification characteristic of shallow bedrock condition in Korea.

• 교육시설
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• 제11권4호
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• pp.15-24
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• 2004

The purpose of this study is to suggest some alternative on site planning of elementary school through investigating the effects of geographical and urban environment on the site. For this, we selected and surveyed 35 schools in Gwangju. The results of this study are as follows. 1) We cannot find out the differences from the use of elementary schools sites on slopes of sites. However, the sunken space between H type buildings in the site slopes facing east or west and the placing the playground on the north side of the site slopes facing north have some problems 2) The number of adjacent road and surrounding environment didn't show any effect. To separate between cars and pedestrians, we need some plans to block cars on the pedestrian gateway and it is much better to intensify the parking area near the school gate that cars come in and out. 3) The degree of satisfaction on the outdoor facilities of these cases shows low level. Therefore, to use the site of schools efficiently, we should secure the spacious playground and make plans to provide some spaces around school building for the static activities of students and teachers. 4) Most of all, the site which is suitable for educational environment should be selected. and also Special Code on the urban plan should be established to develop this one.