• The Journal of Engineering Geology
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• v.2 no.2
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• pp.173-200
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• 1992

The quality of groundwater in the central part of Taegu City is influenced by upstreams of Sin-stream and Beomeo-stream because the stream waters are main source of the groundwater, and chemical composition of the upstream waters has close relationship with andesite and monzonite in the igneous rock terrain. The pH of upstreams are weak acid ~ neutral in the igneous rock area and weak alkaline in the sedimentary rock area. Contents of $Ca^{2+}$ and $Mg^{2+}$ in the streams are apparently high, and $Na^{+}$ content is only slightly high in the sedimentary rock area. But $K^{+}$ content is lower in the Panyaweol formation area than in the monzonite area. The contents of heavy metals and $N0_3^{-}$ are also higher in the sedimentary rock area of residential sections and industrial complexes than those in the igneous rock area. The groundwater is contaminated in comparison to the upstream water of the igneous rock areas, and there are some differences in pollution level between the Panyaweol formation area of residential sections and the Haman formation area of industrial complexes. K, Na, Ca, Mg, Cl, $SO_4$ and $NO_3$ contents in the Haman formation area are relatively higher than those in the Panyaweol formation area. But pH is nearly equal in the two areas. The content of heavy metal ions is still lower than the drinking water standard of Korea and only slightly differs in the two sedimentary rock areas. But the groundwater in the Haman formation area is considerably contaminated by Kongdanstream and Dalseo-stream.

• Proceedings of the Korea Water Resources Association Conference
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• 1986.07a
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• pp.179-180
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• 1986

우리나라 도시권 하천의 특성은 크게 두가지 경우로 나눌 수 있다. 첫째는 대하천의 분류를 끼고 그 중·하류에 위치하여 상류에 수자원의 정량적·정성적 조절 역활을 하는 다목적 댐을 가진 경우와, 큰 하천의 지류이거나 자체 유역내에 수자원의 정량적·정성적 조절 능력을 가진 시설을 갖지 못한 경우라고 볼 수 있다. 수도권 지역의 한강 분류와 부산권의 낙동강 하류, 대청댐 하류-금강 하구언 지역 등은 모두 다 상류에 수자원의 정량적·정성적인 조절 능력을 가진 다목적 댐을 가진 도시권을 가지고 있다. 한편 대구권은 낙동강 제1 지류 금호강 하류에 위치하고 있으며 청주권은 금강의 지류인 무심천 하류에 대전권은 대전천 하류 및 갑천 유역에 위치하고 있으나 상류에 수자원 조절용 댐이나 도시하천의 수질관리를 위한 적정 시설물이 없는 형편이다. 이러한 도시하천의 수자원의 정량적인 문제점은 해당 도시로부터 많은 각종 용수 수요가 급증하고 있는 반면, 공급할 수 있는 능력의 한계성이 크다는 것이다. 직상류에 팔당댐이 운용되고 있는 한강의 경우, 팔당댐은 한전에 의하여 발전전용댐으로 건설되어 저수 및 갈수기엔 하류의 각종 요수 수요를 충족시키기 위한 하천 유지 용수의 공급을 현재로서는 제도상 보장받지 못하고 있으며, 금강 하류의 인접지역(전주, 이리, 군산 등)에 광역 금강 상수도 망으로서 용수 공급을 하고 있으나 대청댐으로서는 하류지역의 요구에 맞추어 댐 운영을 할 수 있는 여건에 있지 못한 실정이다. 대구권이 있는 금호강은 상류에 영천댐이 운영되고 있으나 이는 유역 변경하여 포항 지역에 용수 공급을 하고 있으나 막상 금호강 자체유역에는 안정된 하천 유지용수를 공급할 수 있다. 청주권의 무심천도 계획상은 대청댐의 물을 공급 받을수도 있도록 되어 있으나 현실상으로 상수도 원수로서의 공급마저도 매년 심한 원수 수질 문제(5-6월, 10월경의 취수장 부근의 부영양화 현상으로 인한 악취와 물 맛의 문제)를 1984년부터 겪고 있다. 이와 같이 도시권 하천의 수자원은 자연적, 인위적, 경제적, 법적, 제도적 여러 제한 요소로서 특성을 가지고 있으며 이는 날로 심해 가고 있는 실정이다. 그러므로 최적 물관리 시스템의 개발이 새로이 시작하는 수자원 개발 사업에서는 계획 단계에서부터 절실히 요구되는 바이며 기존 시설물의 관리 운영은 과감히 그 운영 관리 기준을 보완 재 정비하여야 할 것이다. 지금까지 대부분의 수자원 종합 개발 계획이 홍수방이나 용수 공급 및 수력 개발 등에 주력하여 왔으나 이제는 보다 더 수자원의 환경 보전적 차원과 도시의 안정적 발달을 위한 지역 및 권역 계획과 연계지워져서 양적인 안정 공급과 더불어 질적인 향상과 연계지워서 경제-사회적 요구에 부응할 수 있도록 도시권의 수자원을 최적 관리할 수 있는 방안을 강구하여야 할 것이다. 이는 각 도시 하천의 수자원의 정량적·정성적인 특성 및 제한 요소를 충분히 감안하여 수요-공급 개념에 의하여 과감히 기존 시설(예: 팔당댐의 운영, 대청댐의 운영 등)의 관리 운영 체계를 개선하여 나가야 할 것이며, 수질 보전적-환경 보전 차원에서 저수관리 체계를 확고히 할 수 있는 방안을 강구하여야 할 것이다.

• The Journal of the Korea Contents Association
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• v.19 no.1
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• pp.242-255
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• 2019

In this study, we examined the antimicroboal effect against Actinobacillus actinomycetemcomitans and Prevotella intermedia which were the bacteria causing the Periodontopathic by using 34 types of natural plant extracts. Therefore, this study measures growth inhibition activity and Minimum Inhibition Concentration (MIC) of a sample extract with the use of organic solvent extracts in order to analyze the antibacterial effect of natural plant extracts on periodontopathic bacteria. Each of the 34 types of natural plant extracts were extracted by using the ethanol, and subsequently, the size of growth inhibition zone(clear zone, ㎜) of respective extracts were measured through the disk diffusion method. As a result, it was found that the growth inhibitory activity was found for A. actinomycetemcomitans, which is the bacteria causing the Periodontitis, in 13 types of natural plant extracts such as Raphanus sativus, Akebia quinata, Paeonia lactiflora, Belamcanda chinensis, Inula britannics, Houttuynia cordata, Forsythia saxatilis, Gentiana macrophylla, Melia azedarach, Scutellaria baicalensis, Coptis chinensis, Phellodendron amurense, Kalopanax Pictus, etc. In the case of P. intermedia, the growth inhibitory activity was found in 13 types of natural plant extracts such as Raphanus sativus, Angelica acutiloba, Akebia quinata, Belamcanda chinensis, Inula britannics, Houttuynia cordata, Cinnamomum cassia, Aster tataricus, Melia azedarach, Scutellaria baicalensis, Coptis chinensis, Phellodendron amurense, Kalopanax Pictus etc. For A. actinomycetemcomitans, anti-bacterial effect was exhibited in Belamcanda chinensis, Cinnamomum cassia, Kalopanax Pictus, Phellodendron amurense, Coptis chinensis. The Coptis chinensis showed the most excellent growth inhibitory activity in all organic solvent fragment, while P. intermedia showed the growth inhibitory activity in Belamcanda chinensis, Cinnamomum cassia, Meliaazedarach, Phellodendron amurense, and Coptis chinensis.

• Journal of The Geomorphological Association of Korea
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• v.17 no.3
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• pp.17-30
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• 2010

This paper aims to excavate and make storytelling of cultural landforms around Shincheon, Geumho river in Daegu and then to build the strategy for making its application. The main results are as follows. 1) There are main cultural landforms such as Yongdubawi(龍頭岩, river cliff), river cliff, rock shelter(岩蔭), sheeting joint landform, river cave, tor, etc. around Shincheon. 2) there are main cultural landforms such as riverine wetland, ferry, point bar, river cliff, Hwadam(畵潭, pool), Donghwacheon(stream), Mutae(無怠), Chimsan(hill), Yeonamsan(hill), Sanghwadae(river cliff), etc. around Geumho river. 3) It is necessary to excavate and restore cultural landforms around Shincheon and Geumho river for protection, Also the valuable cultural landforms should be designated as cultural assets in order to prevent damage. 4) Considering from application of cultural landforms around Shincheon, natural observation site need to be designed for experiencing culture, history and ecological environment. However, in viewpoint of application of cultural landforms around Geumho river, it is much better to plan a few of Geumho river cultural landform trails for self-guided tour.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.282-286
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• 2002

Seasonal succession of algae and water quality parameters were studied in artificial reservoirs in Daegu city from 2000 to 2001. The algal succession was evaluated with respect to dom-inant class and their frequencies. Succession order of algae in two reservoirs was : Bacillariophyceae longrightarrow Chlo-rophyceae longrightarrow Cyanobacteria longrightarrow Bacillariophyceae longrightarrow Bacillariophyceae longrightarrow Cyanobacteria longrightarrow Cyanobacteria longrightarrow Cyanobacteria. This succession order was different from other studies. The local environment condition maybe affects the succession of algae in these reservoirs. As result of correlation analysis between algal biom-ass and water quality parameters, we got low correlation coefficients. Also we got low correlation coefficients between chlorophyll-a and algal biomass. Between chlorophyll-a and water quality parameters, we got high correlation coefficients. An approach having attention to cell biovolume rather than cell number is made to understand the algal community and the ecosystem of reservoir.

• Journal of The Geomorphological Association of Korea
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• v.17 no.4
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• pp.29-40
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• 2010

The Palgye Plain, located in Chilgok, Buk-gu, Daegu-si, is a floodplain by Palgye-River rising from Mt. Ga one of the mountains in Ring Typed Mountains of Mt. Palgong. The geomorphic surfaces in the study area can be divided into the natural levee, back marsh and confluent fan, and the natural levee and fan have been used as important regions of human activities since the Bronze Age. The alluvium sediments of Palgye-River can be subdivided into the bedrocks, lower gravel deposits, lower sandy deposits, lower silty deposits, upper sand and gravel deposits, and upper silty deposits from the bottom according to the formative ages. The lower gravel deposits correlated to the last glacial stage and the rest to Holocene, respectively. Confluent fans were also formed during the last glacial stage. Moreover, The landscape with land use after 20C was changed to apartment area due to civilization differently from which reflected the characteristics of geomorphic surfaces in the past.

• Journal of the Economic Geographical Society of Korea
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• v.17 no.4
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• pp.702-717
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• 2014

The purpose of this paper is to analyze the residential location preference factors by households' characteristics in the case of Daegu Gyeongbuk households. Under this research purpose, firstly, questionnaire survey of Daegu Gyeongbuk was done, and nextly, AHP(Analytic Hierachy Process) with questionnaire survey results was analyzed. The main results of this study are as follows. Firstly, residential location factors most preferred by Daegu Gyeongbuk households is capital gain, followed by living environment, accessibility of public transportation, accessibility of private car traffic and security. Therefore, we can see Daegu Gyeongbuk households prefer investment value and living amenity together as residential location factors. Secondly, according to the results of AHP by age, below 30th prefer accessibility factors, 40th prefer capital gain and school district factors, and above 50th prefer living environment, natural environment and security factors, relatively. Thirdly, according to the results of AHP by household income, low income households prefer living environment and accessibility factors, middle income households prefer capital gain and accessibility factors, and high income households prefer security, accessibility of private car traffic and view/sunlight factors, relatively.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.1
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• pp.41-46
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• 2023

Iterative reconstruction of CT takes a long time because projection and back-projection are alternatively repeated until taking a good image. To reduce the reconstruction time, we need a fast algorithm for calculating the projection which is a time-consuming step. In this paper, we proposed a new algorithm to calculate the line integral and the algorithm is approximately 10% faster than the well-known Siddon method (Jacobs version) and has a good image quality. Although the algorithm has been investigated for the case of parallel beams, it can be extended to the case of fan and cone beam geometries in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.621-624
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• 2009

The purpose of this study is to select representative rivers of Busan's regional second-class rivers that, as urban rivers, have public open spaces, to identify their environmental characteristics, and thus to present environmental improvement measures for those rivers as natural rivers. First, 5 second-class rivers that have not been covered, and that flow through Busan cities were examined.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.227-232
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• 2019

MRI examination for patients with metal objects has in poor image quality. Metallic implants can result in poor image because magnetic susceptibility causes signal loss and distortion and makes poor imaging, which is called magnetic susceptibility artifact or metal artifact. There are several approaches to reduce metal artifacts. In this study, we study the reduction of metal artifact by VAT and SEMAC techniques. A metal implant used for orthopedic surgery was attached to the phatom and the distortion caused by the artifact was measured under T1WI and T2WI protocols. Several techniques of VAT only and VAT and SEMAC for the reduction of metal artifact were compared. The metal artifact showed a reduction of at least 8% to a maximum of 26% in the VAT-SEMAC. The VAT-SEMAC technique can be applied to patients with orthopedic implants to improve image quality. If scan time and image quality are simultaneously considered in VAT-SEMAC technique, metal artifact will be reduced in clinical practice.