• Journal of Electrochemical Science and Technology
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• 제9권1호
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• pp.44-50
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• 2018

The aims of this study were to determine the corrosion behavior of pure copper in the presence of Desulfovibrio sp. and also to investigate the effects of glutaraldehyde (GD) and isothiazolinone (ISO) on the corrosion behavior of pure copper in the presence of this sulfate-reducing bacteria (SRB) strain by using electrochemical techniques. Electrochemical measurements of pure copper were carried out at specified time intervals (0, 8, 24, 48, and 96 hr) over a period of exposure. Corrosion rates of pure copper from anodic and cathodic Tafel slopes and corrosion potential ($E_{corr}$) were determined. Biofilm and corrosion products on the copper surfaces were observed by Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-Ray Spectrometry (EDS) analyses. The effects of solution types (PC (Postgate's C medium) and SRB (Desulfovibrio sp.)) and exposure times of copper and biocides (ISO or GD) on the corrosion rates of pure copper were evaluated by statistical analyses. As a result of the FESEM analysis, biofilm formation was observed on the surfaces of pure copper exposed to the Desulfovibrio sp. cultures both with and without the biocides. The results show that the pure copper was corroded by Desulfovibrio sp. However, the addition of GD or ISO to the Desulfovibrio sp. culture resulted in a decrease in the corrosion rate of the pure copper. It was also observed that both of the biocides showed a similar effect on pure copper's corrosion rate caused by Desulfovibrio sp.

• 한국지반환경공학회 논문집
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• 제11권2호
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• pp.13-21
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• 2010

일반적으로 강우는 사면의 전단강도와 전단응력 변화에 의한 사면붕괴를 유발하므로 강우강도와 전단강도의 변화는 사면안정해석시 매우 중요한 요소이다. 다양한 강우강도가 사면내의 함수비 변화차이를 유발할 뿐만 아니라, 사면 내 지반의 점착력 및 마찰력의 변화를 유발한다. 본 연구의 목적은 강우재현 실험장치를 이용하여, 강우강도와 사면의 전단강도의 관계를 규명하는 것이다. 사용된 토양은 국내의 사면에서 채취한 것으로 입도분석을 실시하였으며, 종래의 함수비 측정방법 대신 TDR 센서를 사용하여 함수비를 측정하였고, 전단강도 측정을 위해 비배수 직접전단시험을 하였다. 본 연구에서의 결과를 정리하면 첫째, 함수비는 토양의 투수성과 밀접한 관계를 가지며, 강우지속기간은 토양함수비를 결정하는데 중요한 요소이다. 둘째, 강우재현 실험장치를 이용한 안정성 분석은 사면에서의 함수비와 전단응력의 측정이 가능하여, 매우 유용한 사면해석방법이다. 셋째, 함수비와 관련된 비배수 전단응력식을 제시하였으며, 제시한 식은 기존 연구와 비교하여 보다 간편한 것으로 나타났다.

• 환경영향평가
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• 제20권3호
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• pp.381-395
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• 2011

Present work aims to establish an integrated management system of environmental data base for nine typical wind holes or air holes in Korea. It basically deals with definition, geographical distribution, morphological pattern, physical characteristics and anthropogenic environments of wind hole to propose systematic preservation strategy of their periglacial landscape and flora, which are known to be sensitive to global warming. Wind hole, in which cool air blows out during the summer, but mild air comes out during the winter from a cave or hole, is frequently found on northwest- and north-facing slopes on the terminal point of steep talus, block field, and block stream, and can be categorized into three types, i.e., talus, cave and sink types. Environmental characteristics of nine wind holes are analyzed on the basis of their geology, landform, climate, soil, hydrology, vegetation, road, footpath, land-use, and management system, and relevant DB are prepared. Wind hole areas with unique landscape and ecological values need to be designated as a nature reserve, and zoning of core, buffer, and transitional zones are required for the multi-dimensional preservation of periglacial landscape and ecosystem. Phytogeographical values of glacial relict plants, including mountain cranberry(Vaccinium vitis-idaea) at its global southernmost limit at Bangnaeri wind hole, Hongchon County, Gangwon Province of Korea are discussed in detail as a floristic refugia in connection with climate change during the Pleistocene Epoch and potential in-situ and ex-situ preservation sites in the future.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.817-819
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• 2003

Land degradation is a crucial issue in mountainous areas and is manifested in a variety of processes. For its assessment, application of existing models is not straightforward. In addition, data availability might be a problem. In this paper, a procedure for land degradation assessment is described, which follows a four-step approach: (1) detection, inventory and mapping of land degradation features, (2) assessing the magnitude of soil loss, (3) study of causal factors, and (4) hazard assessment by applying decision trees. This approach is applied to a case study in the Middle Mountain region of Nepal. The study shows that individual mass movement features such as debris slides and slumps can be easily mapped by photo interpretation techniques. Application of soil loss estimation models helps get insight on the magnitude of soil losses. In the study area soil losses are higher in rainfed crops on sloping terraces (highest soil loss is 32 tons/ha/yr) and minimal under dense forest and in irrigated rice fields (less than 1 ton/ha/yr). However there is high frequency of slope failures in the form of slumps in the rice fields. Debris slides are more common on south-facing slopes under rainfed agriculture or in degraded forest. Field evidences and analysis of causal factors for land degradation helps in building decision trees, the use of which for modelling land degradation has the advantage that attributes can be ranked and tested according to their importance. In addition, decision trees are simple to construct, easy to implement and very flexible in adaptations.

• 한국시뮬레이션학회논문지
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• 제29권3호
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• pp.19-25
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• 2020

밭 농업 기계는 심한 경사지와 험로, 재배 작물별 정형화되지 않은 재배양식으로 인해 개발이 어렵다. 특히 고추 수확 작업은 많은 시간과 인력이 요구되는 작업으로 고령화가 가속화되는 국내 농촌의 큰 문제점이다. 본 연구는 부족한 인력을 대체하고 작업 시간을 줄이며 수확 작업을 기계화하기 위해 개발된 고추 수확기의 동적 특성을 연구하고자 한다. 고추 수확기의 동적 특성을 분석하기 위해 동역학 프로그램인 Recurdyn을 이용하여 진행하였으며 모든 분석은 공차를 전제로 분석을 진행하였다. 시뮬레이션 결과에 따라 주행 플랫폼이 주행할 수 있는 안전 범위를 제시하였다.

• 한국환경복원기술학회지
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• 제24권5호
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• pp.35-53
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• 2021

A field survey was carried out targeting 59 pine wilt disease control areas distributed in Andong, and the ecological characteristics of the areas affected by pine wilt disease were analyzed using vegetation information, ecological information, and land use information. Vegetation characteristics of Pine wilt disease affected forest area showed a 3-layer vegetation structure, high percentage of accidental occurrence species (37%) and secondary vegetation species (59.6%), appearing 12 taxa naturalized plants and 3 taxa ecosystem disturbance organisms designated by the Ministry of Environment. Ecological information of Pine wilt affected area showed frequent occurrence of water stress in south and west slopes, low lying grounds in mountains, and in well-drained soils. Also, surrounding the area has been used as roads, tombs, and cultivation where intensive human activities were the cause of disturbance and stress to the pine forest. It was analyzed that the pine forest in Andong city suffered extensive damage due to the onset of pine wilt disease while the pine trees were weakened due to continuous human activities. Conclusively, the spread and onset of pine wilt disease are worsened by artificial factors than natural environmental conditions.

• 대한토목학회논문집
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• 제41권3호
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• pp.317-325
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• 2021

1988년 부산에서 처음 발병된 소나무재선충병(Pine Wilt Disease, PWD)은 우리나라 소나무에 막대한 피해를 주고 있는 심각한 질병이다. 정부에서는 2005년 소나무재선충병 방제특별법을 제정하고 피해지역의 소나무 이동 금지와 방제를 시행하고 있다. 하지만, 기존의 예찰 및 방제방법은 산악지형에서 동시다발적이고 급진적으로 발생하는 소나무재선충병을 줄이기에는 물리적, 경제적 어려움이 있다. 따라서 본 연구에서는 소나무재선충병 감염의심목을 효율적으로 탐지하기 위해 무인항공기를 이용한 영상자료를 바탕으로 딥러닝 객체인식 예찰 방법의 활용가능성을 제시하고자 한다. 소나무재선충병 피해목을 관측하기 위해서 항공촬영을 통해 영상 데이터를 획득하고 정사영상을 제작하였다. 그 결과 198개의 피해목이 확인되었으며, 이를 검증하기 위해서 접근이 불가한 급경사지나 절벽과 같은 곳을 제외하고 현장 조사를 진행하여 84개의 피해목을 확인할 수 있었다. 검증된 데이터를 가지고 분할방법인 SegNet과 검출방법인 YOLOv2를 이용하여 분석한 결과 성능은 각각 0.57, 0.77로 나타났다.

• 농업생명과학연구
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• 제53권2호
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• pp.65-75
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• 2019

Stem and root of elm trees have used as traditional medical materials, but there is little information on the distribution and resources of habitats. Korean native growing Ulmus spp. (U. davidiana var. Japonica, U. parvifolia, U. davidiana, and U. macrocarpa) genetic resources studied through The National Forest Inventory of Korea data and field survey. The distributions of U. davidiana var. japonica according to elevation distributed evenly. Both U. parvifolia and U. davidiana were inhabited mostly at less than 200 m of altitude. Each Ulmaceae species widely were distributed nationwide, but a dominant species was different depending on locals. It observed that Ulmaceae inhabits mainly in steep slopes of 31-45 degrees. Most of the habitats regenerated by natural seeding and the most abundant species were a codominant tree. Distribution of trees in U davidiana var. japonica was 7 m-13 m, and in young U. parvifolia and U. macrocarpa, more than 25% of young trees less than 7 m observed. The distribution of the diameter of breast height of the U. davidiana var. japonica was 46.4% for 11-20 cm, 52.6% for 11-20 cm in U. parvifolia. The average T/R ratio was 0.83, and the mean weight ratio of root bark was 62%. As the results of this study, the domestic Ulmaceae biomassare very small. It is difficult to harvest in that the habitat on the slope. Thus, it is too hard to develop functional materials using biomass at present. Therefore, it is necessary to develop technology for the selection and propagation of elite trees of Ulmaceae.

• 산업경영시스템학회지
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• 제44권1호
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• pp.26-36
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• 2021

The topic of this study is the field of humanitarian logistics for disaster response. Many existing studies have revealed that compliance with the golden time in response to a disaster determines the success or failure of relief activities, and logistics costs account for 80% of the disaster response cost. Besides, the agility, responsiveness, and effectiveness of the humanitarian logistics system are emphasized in consideration of the disaster situation's characteristics, such as the urgency of life-saving and rapid environmental changes. In other words, they emphasize the importance of logistics activities in disaster response, which includes the effective and efficient distribution of relief supplies. This study proposes a mathematical model for establishing a transport plan to distribute relief supplies in a disaster situation. To determine vehicles' route and the amount of relief for cities suffering a disaster, it mainly considers the urgency, effectiveness (restoration rate), and uncertainty in the logistics system. The model is initially developed as a mixed-integer nonlinear programming (MINLP) model containing some nonlinear functions and transform into a Mixed-integer linear programming (MILP) model using a logarithmic transformation and piecewise linear approximation method. Furthermore, a minimax problem is suggested to search for breakpoints and slopes to define a piecewise linear function that minimizes the linear approximation error. A numerical experiment is performed to verify the MILP model, and linear approximation error is also analyzed in the experiment.

• 한국환경복원기술학회지
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• 제25권3호
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• pp.83-95
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• 2022

This study aims to present primary data for habitat restoration and artificial breeding conditions of L. unmunsana by identifying the habitat conditions and the larvae's food sources. In order to investigate the habitat characteristics of the adult L. unmunsana and land snails, which are the primary food sources for the larvae, field surveys were conducted on a total of 10 habitats in south-central parts of Korea including Sanseongcheon, Jeonju. The results revealed that the L. unmunsana habitat in the Sanseongcheon area had a broadleaf forest with a multi-layered vegetation structure, adjacent water features, and the north/northeast/northwest slopes with little effect of artificial lighting. The adult L. unmunsana in the Sanseongcheon area appeared from the end of May to the end of June, and was especially intensively observed around the middle of June. The most active time was from 23:30 to 00:30 with a temperature range of 19~22℃ and higher than 80% humidity. The peak count of the observed adults L. unmunsana was a total of 774 on June 11, 2021. In the case of land snails, 11 families and 23 species were observed in 10 habitats of L. unmunsana, and Euphaedusa fusaniana was the most extensive and the most observed in the five survey areas. The land snails of L. unmunsana habitats are mostly found under the organic layers of leaves and a fallen tree branch in broadleaf forests, where a thick organic material layer buffers temperature changes and provides high humidity for various snails. These habitat conditions are suitable for the larva of L. unmunsana and land snails to inhabit, feed, hide and hibernate.