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Arsenic Distribution and Solubility in Groundwater of Okcheon Area (옥천군 북부 지역 지하수의 비소 분포와 비소 광물의 용해도 특성)

  • Chon, Chul-Min;Kim, Kue-Young;Koh, Dong-Chon;Choi, Mi-Jung
    • Journal of the Mineralogical Society of Korea
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    • v.22 no.4
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    • pp.331-342
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    • 2009
  • Groundwater samples were collected from the bedrock aquifers related with Okcheon metasedimentary rocks. Arsenic (As) concentrations in the samples varied between 0.0051 and 0.887 mg/L, with an average of 0.0248. Cations and anions of groundwaters had no relationship with As contents as well as with spatial distribution of geology in the area. Pyrite, chalcopyrite and arsenopyrite in the core samples of the monitoring wells were identified in thin section, X-ray diffraction (XRD) and electron probe microscope analysis (EPMA). It was suggested that these minerals are responsible for the As in groundwater. The groundwater showed saturations with respect to calcite $(CaCO_3)$, dolomite (CaMg$(CO_3)_2$) and Magnesite $(MgCO_3)$. $HAsO_4{^{2-}}$ activities in the groundwater samples were close to $Ca_3(AsO_4)_2(c)$ and $Mn_3(AsO_4)_2(c)$ solubility isotherms, indicating that the maximum As contents in groundwater are secondly controlled by the precipitation and dissolution of carbonate minerals due to alkaline and oxic nature of the groundwater (pe+pH>10).

Interpretation of Subsurface Fracture Characteristics by Fracture Mapping and Geophysical Loggings (단열조사 및 물리검층을 통한 지표 하 단열특성 해석)

  • Chae, Byung-Gon;Lee, Dae-Ha;Kim, Yu-Sung;Hwang, Se-Ho;Kee, Weon-Seo;Kim, Won-Young;Lee, Seung-Gu
    • Journal of the Korean GEO-environmental Society
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    • v.2 no.1
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    • pp.37-56
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    • 2001
  • As a preliminary study to establish fracture network model in crystalline rocks, detail investigation on fracture characteristics were performed. Five fracture sets were determined on the basis of regional survey of geological structures and fractures on outcrops. Among the fracture sets, S1 set has the highest density and longest trace length of fractures which was identified on surface in the study area. S4 and S5 sets are composed of foliations and foliation parallel shear joints of gneisses, which are very important sets at the aspect of weighting of fracture length. For characterization of subsurface fractures, detail core logging was performed to identify fractures and fracture zones from five boreholes. Acoustic televiewer logging and borehole geophysical loggings produced images, orientations and geophysical properties of fractures which intersect with boreholes. According to the result of the investigations, subsurface fractures can be grouped as three preferred orientations(B1, B2 and B3), which correspond to S1, S2 and S4/S5 of surface fracture sets, respectively. Actually, B1 set is expected to be intensely developed at subsurface. However, it has low frequency of intersection with boreholes due to its parallel or sub-parallel direction to boreholes. According to the inference of conductive fractures, B1 and B3 sets have possibilities of water flow and their intersection lines are also thought to consist of important conduits of groundwater flow. In particular, faults which are parallel to foliations control major groundwater flow in the study area.

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A Case Study on the Creating Artificial Planting Ground on the Waste Landfill Sites -In Case of the Bank Isolated Section Planting Layer at the Landfills of Satellite Cities of Seoul- (폐기물매립지 인공식재지반 조성 사례연구 -수도권매립지 제방이격구간 식재층을 대상으로-)

  • 조주형;이재근
    • Journal of the Korean Institute of Landscape Architecture
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    • v.29 no.1
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    • pp.131-139
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    • 2001
  • This paper aims at surveying through case studies the planting possibility on the interval artificial ground between the bank and the core landfill of the first section of works in the SUDOKWON Landfill area landfill area which was completed, followed by the layer-on-layer landfill process involving the latch or sealing layer against emitting landfill gas from the reclaimed waste. The survey results are as follows; 1. The layers of the artificial planting ground on the landfill were established on the basis of top-on-top procedure for a waste layer, a topping soil layer (T=50cm), a gas blocking layer (broken stones T=30cm), a filter layer (non-woven fabric 700g), a sheet protecting soil layer (T=20cm), and a blocking layer (HDPE SHEET 2.0mm), an irrigation layer (SAND T=30cm), a filter layer (non-woven fabric 700g), a sheet protecting soil layer (T=20cm), and a blocking layer (HDPE SHEET 2.0mm), an irrigation layer (SAND T=30cm), a filter layer (non-woven fabric 700g), a planting layer (T=90cm+), a top mound (T=2m). 2. Since no direct damage on the planting layer affected by the landfill gas was detected, planting is found to be still possible and successful except the severely unequal subsidence portion. 3. The mortality rate is discovered different on different trees: Pinus thunbergii (H3.0$\times$W1.0m) 11.25%, Pinus thunbergii (H2.5$\times$W0.8m) 4.73%, Koelreuteira paniculata 8.67%, Hibiscus syriacus 5.68%, Deutzia parviflora 6.50%, Forsythia koreana 8.17%, Rho. yedoense v. poukhanese 32.22%, and Spiraea pru v. symplicifolia 18.89%; although the last two of which are generally considered to have a strong generic growing character, they are subject to be weakened when exposed to the contaminated microclimate of the site like landfill gas. 4. The damage rates, on Pinus thunbergii, Koelreuteria paniculata, Hibiscus syracus, Forsythia koreana, Deutzia parviflora, Rho. yedoense v. poukhanense were shown to decrease to 7.31-17.69% in the second check (June 2000) lower than 5.77-46.92% in the first examination (June 1999), whereas the damage on Spiraea pru v. symplicifolia relatively increased. It is believed that preparatory method of the air pollution, change of temperature, odor by emitting landfill gas, and minute dust from vehicles should be made, and a research on this matter will be conducted in the near future.

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A Case Study on Seismic Refraction Tomography Survey for Subsurface Structure Interpretation (지하구조 해석을 위한 탄성파 굴절법 토모그라피 탐사 사례연구)

  • 유영준;유인걸;송무영
    • The Journal of Engineering Geology
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    • v.11 no.2
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    • pp.163-174
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    • 2001
  • For quantitative evaluation of geotechnical engineering properties such as rippability and diggability, clear interpretation on the subsUJiace velocity structures should be preceded by figuring out top soil, weathered and soft rock layers, shape of basement, fracture zones, geologic boundary and etC. from the seismic refraction data. It is very important to set up suitable field parameters, which are the configuration of profile and its length, spacings of geophones and sources and topographic conditions, for increasing field data Quality. Geophone spacing of 3 to 5m is reconunended in the land slope area of house land development site. In refraction tomography technique, the number of source points should be more than a Cluarter of available channel number of instrument and the subsurface structure interpretation can be decreased the artifact of inversion by topographic effect. Compared with core logging data, it is shown that the velocity range of the soil is less than 700m/s, weathered rock 700~1,200m/s, soft rock 1,200~1,800m/s on the velocity tomogram section. And the upper limit of P-wave velocity for rippability is estimated 1,200 to 1,800m/s in land slope area of gneiss.

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Longitudinal Analysis of Information Science Research in JASIST 1985-2009 (정보학연구의 25년간 동향 분석 : JASIST 논문을 중심으로)

  • Seo, Eun-Gyoung
    • Journal of the Korean Society for information Management
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    • v.27 no.2
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    • pp.129-155
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    • 2010
  • In recent years, the changes in information technology have been so dramatic and the rate of changes has increased so much that information science research rigorously evolves with the passage of time and proliferates in diverging research directions dynamically. The aims of this study are to provide a global overview of research trends in information science and to trace its changes in the main topics over time. The study examined the topics of research articles published in JASIST between 1985 and 2009 and identified its changes during five 5 year periods. The study found that the most productive area has consistently been 'Information Retrieval', followed by 'Informetrics', 'Information Use and Users', 'Network and Technology', and 'Publishing and Services'. Information retrieval is a predominant core area in Information Science covering computer-based handling of multimedia information, employment of new semantic methods from other disciplines, and mass information handling on virtual environments. Currently Informetric studies shift from finding existing phenomena to seeking valuable descriptive results and researchers of information use have concentrated especially on information-seeking aspects, so adding greater sophistication to the relatively simple approach taken in information retrieval.

Fast Delineation of the Depth to Bedrock using the GRM during the Seismic Refaction Survey in Cheongju Granite Area (굴절법 탄성파탐사 현장에서 GRM을 이용한 청주화강암지역 기반암 깊이의 신속한 추정)

  • Lee, Sun-Joong;Kim, Ji-Soo;Lee, Cheol-Hee;Moon, Yoon-Sup
    • Economic and Environmental Geology
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    • v.43 no.6
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    • pp.615-623
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    • 2010
  • Seismic refraction survey is a geophysical method that delineates subsurface velocity structure using direct wave and critically refracted wave. The generalized reciprocal method(GRM) is an inversion technique which uses travel-time data from several forward and reverse shots and which can provide the geometry of irregular inclined refractors and structures underlain by hidden layer such as low velocity zone and thin layer. In this study, a simple Excel-GRM routine was tested for fast mapping of the interface between weathering layer and bedrock during the survey, with employing a pair of forward and reverse shots. This routine was proved to control the maximum dip of approximately $30^{\circ}C$ and maximum velocity contrast of 0.6, based on the panel tests in terms of dipping angle and velocity contrast for the two-layer inclined models. In contrast with conventional operation of five to seven shots with sufficient offset distance and indoor data analysis thereafter, this routine was performed in the field shortly after data acquisition. Depth to the bedrock provided by Excel-GRM, during the field survey for Cheongju granite area, correlates well with the elevation of the surface of soft rock from the drill core and SPS logging data. This cost-effective routine developed for quickly delineating the bedrock surface in the field survey will be readily applicable to mapping of weathering zone in narrow zone with small variation of elevation of bedrock.

Damage Analysis and Accuracy Assessment for River-side Facilities using UAV images (UAV 영상을 활용한 수변구조물 피해분석 및 정확도 평가)

  • Kim, Min Chul;Yoon, Hyuk Jin;Chang, Hwi Jeong;Yoo, Jong Su
    • Journal of Korean Society for Geospatial Information Science
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    • v.24 no.1
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    • pp.81-87
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    • 2016
  • It is important to analyze the exact damage information for fast recovery when natural disasters cause damage on river-side facilities such as dams, bridges, embankments etc. In this study, we shows the method to effectively damage analysis plan using UAV(Unmanned aerial vehicle) images and accuracy assessment of it. The UAV images are captured on area near the river-side facilities and the core methodology for damage analysis are image matching and change detection algorithm. The result(point cloud) from image matching is to construct 3-dimensional data using by 2-dimensional images, it extracts damage areas by comparing the height values on same area with reference data. The results are tested absolute locational precision compared by post-processed aerial LiDAR data named reference data. The assessment analysis test shows our matching results 10-20 centimeter level precision if external orientation parameters are very accurate. This study shows suggested method is very useful for damage analysis in a large size structure like river-side facilities. But the complexity building can't apply this method, it need to the other method for damage analysis.

Evaluation of Hydrogeochemistry of Geothermal Water at Heunghae, Pohang Using Pumping Test Results (양수시험에 의한 포항 흥해지역 심부지열수의 수리지화학적 규명)

  • Cho Byong-Wook;Yun Uk;Song Yoon-Ho
    • Journal of Soil and Groundwater Environment
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    • v.11 no.3
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    • pp.20-30
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    • 2006
  • Hydrogeochemistry of deep geothermal water (temperature: $42.2-47.9^{\circ}C$) at Heunghae, Pohang was evaluated using core logging, temperature and electrical conductivity (EC) logging before and after pumping tests, chemical analysis of geothermal water with depth, and observation of water quality variations during pumping tests. The geology of the area is composed of highly fractured marine sedimentary rocks. The hydrogeochemistry of geothermal water varies with drilling depth, distance from the coast, and pumping duration. According to the temperature and EC variations during 4 times of pumping tests, main aquifer of the area is considered as the fractured zones (540 to 900 m) developed in rhyolitic rocks. The high content of Na and $HCO_3$ in geothermal water can be explained by the inflow of deep groundwater from inland regulated by dissolution of silicates and carbonates. High TDS, Na and Cl concentrations indicate that the geothermal water was also strongly affected by seawater. The molar ratios of Na:Cl ($0.88{\sim}2.14$) and Br:Cl ($21.0{\sim}24.9{\times}10^{-4}$) deviate from those of seawater (0.84 and $34.7{\times}10^{-4}$, respectively), suggesting that water-rock interaction also plays an important role in the formation of water quality.

Home Economics Curriculum Development and Application of Clothing Life Culture Area Based on the Interpretive Perspective on Educational Curriculum (해석적 관점을 중심으로 한 가정과교육 의생활 문화 영역의 교육과정안 개발 및 적용)

  • Bae, Hyun-Young;Lee, Hye-Ja
    • Journal of Korean Home Economics Education Association
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    • v.20 no.3
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    • pp.31-47
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    • 2008
  • In this study the interpretive perspective means a point of view on educational curriculum in which in order to reach the understanding of the meaning of the behaviors and beliefs of human beings, and the historical and cultural products, the process of discussing on the basis of historical and cultural knowledge is very important. The developed curriculum means the one that consists of the goal of the curriculum, the contents of the curriculum, lesson plans, and the instruction-learning materials. This study has been carried out in four steps: conceptualization, development, application and evaluation. This study has tried to propose some changes in the contents of clothing life education on the basis of the interpretive perspective by firstly, assuming some core concepts that were related to clothing life education in Home Economics and secondly, organizing the contents of the clothing life culture area based upon historical and cultural materials. The results of the application of the developed curriculum came out positive. The strong points of the developed curriculum showed that for the students the curriculum was helpful in seeking answers to such questions as 'who I am' and 'what kind of being I am' through the perception of traditional culture and clothing life. In addition, the developed learning contents were recognized as new knowledge. It also showed that teaching contents with a focus on the interpretive perspective could play a role as reflection for the practice and for the arrival at the final perception. A weak point of the developed curriculum is that the Home Economics teachers themselves might find difficulty preparation for teaching this material because of their limited understanding and knowledge of the historical and cultural materials about clothing life.

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Understanding of the Career Development in the Job Shadowing of the Beauty Major College Students (뷰티미용전공 전문대학생의 간접적 직무체험 (Job Shadowing)에서 직업진로 발달의 이해)

  • Cho, Eun-hee;Park, Joo-Ho
    • Journal of vocational education research
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    • v.37 no.1
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    • pp.77-100
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    • 2018
  • The purpose of this study was to explore how the college students of the beauty department changed their perspective about jobs, career development, and self-reflection in the process of job shadowing. We selected 8 students who were enrolled in the beauty department of a college located in the capital area and conducted individual in-depth interviews with them. According to the result of the study, First, participants have learned attitude, knowledge, competence, and an important matter necessary to achieve a excellent performance in the beauty job. In particular, they figured out that a core competency for a successful beauty job is to share a social relationship with the clients. Second, they recognized that doing a beauty job is very tough and then set a criteria to make a decision of their future job. Doing a Job shadowing made them being change in the area of job and their job perspective. Finally, they looked themselves back how they are satisfying with developing their career at the beauty department. This study is significantly meaningful in that it contextually showed how the college students are developing their job careers through an indirect job experience from a constructive point of view. Moreover, this study is different from the existing studies focusing on student's direct work experiences such as the existing internship programs, which focused on exploring the student's indirect work experience and the process of their vicarious learning. The result of the current study has a practical implication in terms of providing a basic perspective for career education for students of colleges.