• Journal of the Korean GEO-environmental Society
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• v.16 no.4
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• pp.5-12
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• 2015

Civil engineers have taken the numerous slope monitoring data for an engineering project subjected to hazard potential of slide. However, the topics on how to deal with and draw out proper information from the data related to the slope behavior have not been widely discussed. Recently, several researchers had installed the real-time monitoring system to cope with slope failure; however they are mainly focused on the hardware system installation. Therefore, this study tries to show how the measured data could be grouped and connected each other. The basic idea of analyzing method studied in this paper came from the clustering, which is the part of data mining analysis. Therefore, at the base of classification of time series data, the authors suggest three mathematical data analyzing methods; Average Index of different displacement ($AD_{i,j}$), Difference of average relative displacement ($\overline{RD}_{i,j}$) and Coordinate system of average and relative displacement ($\overline{RD}$, AD). These analyzing methods are based on the statistical method and failure mechanism of slope. Therefore they showed clustering relationships of the similar parts of the slope which makes the same sliding mechanism.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.7-7
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• 2016

인도네시아 산불에 의한 연무는 동남아시아 인접한 국가들에 있어서 심각한 환경문제 중 하나이다. 국제적으로 심각한 문제를 야기하는 인도네시아의 산불은 건조기에 강수량이 적게 내리는 극심한 가뭄 조건에서 발생한다. 건조기 강수량을 모니터링 하는 것은 산불 발생 가능성을 예측하기 위해 중요하지만 산불을 사전에 예방하고 영향을 최소화하기에는 부족하다. 따라서 산불에 대한 선제적 사전예방을 위해서는 수개월의 선행예측 기간을 갖는 조기경보 시스템이 절실하다. 따라서 본 연구는 인도네시아 산불에 대한 선제적 대응을 위한 강수량 예측시스템을 개발하고 예측성을 평가하여 동남아시아 지역의 화재 연무 조기경보 시스템의 시제품(Prototype)을 개발하는데 있다. 강수량 예측을 위해서 APEC 기후센터의 계절예측정보의 활용 정도에 따라서 4가지 서로 다른 방법을 통합하여 사용하였다. 예측정보 기반의 방법들로는 대상지역의 강수량 예측을 위해서 대상 지역 상공의 계절예측 강수자료를 보정을 통해 직접적으로 사용하는 SBC (Simple Bias Correction) 방법과 대상 지역 상공의 강수 예측자료를 사용하는 대신에 지역 강수량과 높은 상관 관계를 보이는 다른 지역의 대리변수를 예측인자로 사용하는 MWR (Moving Window Regression) 방법이 있다. 또한 예측자료의 사용 없이 과거자료 기반의 기후지수(Climate Index) 중에서 지체시간을 고려하여 지역 강수량과 높은 상관관계를 갖는 경우 예측에 활용하는 관측자료 기반의 CIR (Climate Index Regression) 방법과 예측기반 MWR과 관측기반의 CIR 방법에서 선정된 예측인자를 동시에 활용하는 ITR (Integrated Time Regression) 방법이 사용되었다. 장기 강수량 예측은 보르네오 섬의 4개 지역에서 3개월 이하의 선행예측기간에 대하여 0.5 이상의 TCC (Temporal Correlation Coefficient)의 값을 보여 양호한 예측성능을 보였다. 예측된 강수량 자료는 위성기반 관측 강수량 및 관측 탄소 배출량 관계에서 결정된 강수량의 임계값과의 비교를 통해 산불발생 가능성으로 환산하였다. 개발된 조기경보 시스템은 산불 발생에 가장 취약한 해당지역의 건조기(8월~10월) 강수량을 4월부터 예측해 산불 연무에 대한 조기경보를 수행한다. 개발된 화재 연무조기경보 시스템은 지속적인 개선을 통해 현장 실효성을 높여 동남아국가 정부의 화재 및 산림관리자들에게 보급함으로써 동남아의 화재 연무로 인한 환경문제 해결에 기여할 수 있으리라 판단된다.

• Korean Journal of Environment and Ecology
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• v.19 no.3
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• pp.287-298
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• 2005

This study was carried out to offer the raw data on conservation of land and natural environment by constructing groups of indicators to objectively and rationally assess the sustainable natural ecosystem and present the direction for establishing and planning the environmental policy. There were selected that four assessment items were biotic, abiotic, qualitative, and functional factor. And there were extracted fifty-six indicators including density, total nitrogen, hemeroby degree, and goods production. As assessment items and indicators were over 0.6, the design of questionnaire showed no great problem. In the results of correlation analysis of assessment indicators, sociality and dominance was highly correlative in biotic factor, soil property and aspect in abiotic factor, naturalized and urbanized index in qualitative factor, and protection of landslide and soil erosion were too correlative. In the results of deciding the dimension by multidimensional scaling, as stress values were from 0.042 to 0.133, index of fit over 0.9, there no statistical problems. In case of X axis, biotic factor was structure, viewpoint in abiotic factor, composition in qualitative factor, and object in functional factor, and Y axis was shaped Into form, range, structure, and activity.

• Korean Journal of Environmental Biology
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• v.35 no.2
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• pp.105-115
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• 2017

The present study is to understand the Bongseonsa stream in the National Arboretum fish fauna variation through comparison with historical data and to evaluate the stream health situated. We performed investigations over three times from April to September 2015. In the survey, 2,960 individuals which belonging to 22 species, 8 families were collected. Dominant species by number was Zacco platypus and subdominant species was Zacco koreanus. Seven Korean endemic species (Squalidus gracilis majimae, Microphysogobio yaluensis, Zacco koreanus, Koreocobitis rotundicausata, etc) were observed and showed a ratio of 36.4%. The community analysis revealed that the structure of fish community in the study sampling sites was instability in having dominance 0.79 (${\pm}0.15$), diverse 1.21 (${\pm}0.60$), evenness 0.58 (${\pm}0.15$) and species richness 1.49 (${\pm}0.83$). The values in the Qualitative Habitat Evaluation Index (QHEI) was averagely 122.9 (${\pm}44.8$) in the Bongseonsa stream and this was showed to have favorable habitat surroundings. As a result of tolerance guild analysis, the total number of sensitive species and intermediate species were higher than tolerant species. Analysis was divided into A and B two groups of fiducial 12.25% in Cluster analysis degree of similarity between study sampling sites. Fish Assessment Index (FAI) was rated A and B grade in Bongseonsa stream that stream health showed favorable. However Wangsuk stream as a urban stream rated C grade and analysed the lowest grade in the whole study sampling sites. There was high correlation beteween FAI and various indexes, dominance, diverse, evenness and sensitive species and intermediate species.

• Korean Journal of Ecology and Environment
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• v.55 no.1
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• pp.84-98
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• 2022

Estuary is important in terms of biodiversity because it has the characteristics of transition waters, created by the mixing of fresh- and seawater. The estuarine water circulation provides a variety of habitats with different environments by inducing gradients in the chemical and physical environment, such as water quality and river bed structure, which are ultimately the main factors influencing biological community composition. If the water circulation is interrupted, the loss of brackish areas and the interception of migration of biological communities will lead to changes in the spatial distribution of biodiversity. In this study, among the sites covered by the Estuary Aquatic Ecosystem Health Assessment, we selected study sites where changes in biodiversity can be assessed by spatial gradient from the upper reaches of the river to the lower estuarine area. The α-, γ- and β-diversity of diatom, benthic macroinvertebrates, and fish communities were calculated, and they were divided into open and closed estuary data and compared to determine the trends in biodiversity variation due to estuarine circulation. As results, all communities showed higher γ-diversity at open estuary sites. The benthic macroinvertebrate community showed a clear difference between open and closed estuaries in β-diversity, consequently the estuarine transects were considered as a factor that decreases spatial heterogeneity of their diversity among sites. The biodiversity trends analyzed in this study will be used to identify estuaries with low γ- and β-diversity by community, providing a useful resource for further mornitoring and management to maintain estuarine health.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.260-269
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• 2009

Hwabuk Dam has been under construction to reduce flood damage in Nakdong River watershed and to supply stable water for middle area of Gyeongbuk Province. Therefore, fish investigation in up and downstream of the dam was conducted from 2004 to 2008 in order to determine any negative effect on fish community due to dam construction and to use as fundamental data for conserving species diversity and maintaining stream health. According to data analysis on water quality, temperature, dissolved oxygen, pH, suspended solids, and total E-coli had seasonal variation, but they did not significantly differ in sites. However, biological and chemical oxygen demand, chlorophyll-a, nitrogen, and phosphorus representing organic matter and nutrient concentration were higher in upper site and decreased to lower site so that they differed by site. Concentration of arsenic among the heavy metals was less than 0.05 mg $L^{-1}$, which is regulated for protection of human health in water quality standard, except for 0.092 mg $L^{-1}$ in June 2005. During the study period, the total number of fish caught from the 6 sites was 10,263 representing 7 families 19 species. Among them, dominant and subdominant species were Korean chub (Zacco koreanus, 62.5%) and Chinese minnow (Rhynchocypris oxycephalus, 10.6%) which inhabit mostly in mid and upper streams, Korea. Among the 19 species, Korean endemic species were 9 species (47.4%) including Korean slender gudgeon (Squalidus gracilis majimae), Korean dark sleeper (Odontobutis platycephala), and Korean shiner (Coreoleuciscus splendidus). There was several individuals of the $1^{st}$-class endangered species, Naktong nose loach (Koreocobitis nahtongensis), caught in 2005${\sim}$2007, and no introduced species of fish was found in entire sampling period. According to result of community analysis, dominance index decreased toward lower site, but diversity and richness indices increased toward lower site. The equation of length-weight relationship on the dominant species was TW=0.000003$(TL)^{3.2603}$. The parameter b in the equation was greater than 3.0 indicating good nutritional condition in the populations. Compared to populations of Korean chub in other streams, the population in Hwabuk Dam watershed had higher mean of condition factor by size indicating better growth rate. With fish fauna and multi-metric health assessment model in each sampling attempt, index of biotic integrity (IBI) was evaluated and it resulted mostly in good (26${\sim}$35) and excellent (36${\sim}$40) condition in all sites, and the mean of IBI was the highest in site 5. The results indicate that it is very important to study not only environmental impact assessment with fish composition but also stream health assessment in order to conserve healthy aquatic ecosystem.

• Journal of the Society of Disaster Information
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• v.8 no.3
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• pp.242-257
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• 2012

Korea's population change trend is the aging and feminization as Reduction in mortality, average life extension. and is further increased Reduction of birth rate and aging population. if Our country concluded FTA(Free Trade Agreement) with the United States, Europe and China etc. labor-intensive industries will be the decline. Then, the construction workers' jobs are continually reduced. This is critical to the nation's economic, social and environmental influences due to Shortage of construction workforce and increasing labor costs. Eventually this is a major factor in reduced construction productivity. Therefore, this study is presented as a construction productivity development prospects on the value-added analysis per Labour productivity employee from Construction market trends, industry-specific productivity index, industry trends Employed, age tiered workforce trends, women's workforce trends, labor time trend, foreign workers, workforce trends, analysis of trends in construction contract, awarded by Company Size trends, construction management analysis index.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.728-728
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• 2012

본 연구에서는 자연하상 복원을 위한 하상복원공법을 개발하여 시험구간에 적용하였다. 공법적용 대상 지역은 안양시역내의 안양천 일정구간으로 화창교로부터 상류방향으로 약 500m 거리에 웅덩이 수제공법이 적용되어 있으며, 그로부터 다시 상류방향으로 130m 떨어진 거리에 낮은 바닥막이 공법이 적용되어 있다. 낮은 바닥막이 공법의 경우 완만한 곡류사주의 직상류 부로서 강한 수류와 함께 빠른 유속이 형성될 경우 하상의 세굴이 예상되어 이를 방지하기 위해 저수로의 유하방향으로 완만한 호형으로 설치하였으며, 웅덩이형수제 공법은 완만한 곡류로 좌안 수충부가 형성되어 있어 물의 흐름방향과 유속을 제어하여 흐름에 의한 호안침식을 방지하기 위해 현 위치를 선정 및 적용하였다. 첫 번째, 경관모니터링 결과 낮은 바닥막이 공법과 웅덩이 수제 공법을 적용한 구간에서 대규모 홍수 이후에도 저수로 호안과 하상의 안정성이 유지되었으며, 이는 공법 설치 전 후 하상 경관의 변화가 거의 없어 수리적 안정성 유지를 하고 있다고 볼 수 있다. 또한 웅덩이 수제 공법 설치 후, 미소서식처가 형성되면서 포식자인 왜가리, 백로류를 지속적으로 관찰할 수 있어 어류서식처로서의 기능이 강화되었음을 간접적으로 확인하였다. 두 번째, 생태계 모니터링 결과 저서성 무척추동물의 경우 한국오수생물지수(KSI)는 낮은 바닥막이 공법을 적용하여 하상구조가 변화된 조사 지점 st.1의 환경상태가 "양호"에서 "최적"으로 변화하였기 때문에 공법 적용이 서식처 건강성 증진에 도움을 준 것으로 판단된다. 세 번째, 수질 모니터링 결과 용존산소의 경우 상부지점보다 하부지점이 낮게 나타나는 결과를 보여주었다. 낮은 바닥막이 공법에 의한 용존산소 상승효과보다는 다양한 서식처의 제공이라는 측면이 보다 중요한 효과를 나타낸다. 결과적으로, 공법의 실용화를 위한 적용 공법에 대한 생태계 모니터링 및 평가를 통하여 하천에서의 다양한 서식처(Habitat) 창출을 통해 수생 생물의 다양성을 증진시키고, 하천 하상공법에 대한 생태계의 조사 및 평가기법을 확보하여 연구성과를 다른 하천으로의 확대 적용 할 수 있을 것으로 기대한다.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.4
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• pp.69-76
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• 2015

Recently, environmental sustainability of the transitional explosives and propellants is an issue of growing importance in energetic materials. For examples, ammonium perchlorate(AP) as an solid propellants oxidizer could create a poisonous gas and atmospheric pollutions, such as HCl. Among the several oxidizers, hydrazinium nitroformate(HNF) is an effective candidate substance for eco-friendly oxidizer, which has high density, pressure index, and less smog generating property during combustion for the Divert and Attitude Control System(DACS). This study was confirmed a synthesis through various conditions, was performed for the essential data of solubility the crystallization process. Also, crystallization process such as cooling, drowning-out and sonication were performed.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.6
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• pp.76-82
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• 2016

Recently, environmental sustainability of the transitional explosives and propellants is an issue of growing importance in energetic materials. For examples, ammonium perchlorate(AP) as an solid propellants oxidizer could create a poisonous gas and atmospheric pollutions, such as HCl. Among the several oxidizers, hydrazinium nitroformate(HNF) is an effective candidate substance for eco-friendly oxidizer, which has high density, pressure index, and less smog generating property during combustion for the thrust control system. This study was controlled the size distribution and shapes through various conditions. Length and diameter ratio(L/D) of crystals has below 1 : 3, and the particle size was two types of $200{\mu}m$ and $50{\mu}m$.