• Title/Summary/Keyword: h-지수

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Assessment of tributary water quality using integrated Water Quality Index (통합수질지수를 이용한 지류지천 수질평가)

  • Kal, Byungseok;Park, Jaebeom;Kim, Sanghun;Im, Taehyo
    • Journal of Wetlands Research
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    • v.19 no.3
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    • pp.311-317
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    • 2017
  • In this study, the water quality index was calculated using the water quality monitoring data in the Nakdong River water system and the water quality status was compared with the living standard. The water quality index was selected by the RWQI method CCME-WQI currently used by the Ministry of Environment. The water quality items were selected as 7 items for pH, DO, EC, water temperature, TOC, T-N and T-P. The evaluation period was selected from the last three years (2013~2015) and water quality monitoring data measured within the period were used. As a result of the evaluation, the results of the previous evaluation showed similar tendency to the index of living environment, but the monthly evaluation showed different BOD and T-P results. Therefore, it is concluded that it is more reliable that more complex evaluation than single water quality evaluation is needed for efficient river management.

Comparing Centrality Measures for Analyzing Co-authorhip Networks (공저 네트워크 분석을 위한 중심성 척도 비교 분석)

  • Lee, Jae Yun
    • Proceedings of the Korean Society for Information Management Conference
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    • 2013.08a
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    • pp.27-30
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    • 2013
  • 공동연구 네트워크의 대표적인 사례인 공저 네트워크는 오랫동안 네트워크 분석의 대상으로 다루어져 왔다. 최근에는 가중 네트워크로서 공저 네트워크에 대한 연구가 활발해지면서 연구자의 영향력을 측정하려는 몇 가지 척도가 제안되었다. 이 연구에서는 공저 네트워크에서의 중심성을 측정하기 위해서 사용된 척도인 가중페이지랭크, 공동연구 h-지수와 공동연구 hs-지수, 복합연결정도중심성, c-지수에 대해서 비교 분석해본다.

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Study of Ethane Performance at Two-Stage Cascade Vapor Compression System (에탄을 사용한 2원 냉동 시스템의 성능 평가)

  • Rahadiyan, Lubi;Kim, Y.G.;Chung, H.S.;Jeong, H.M.
    • Journal of Power System Engineering
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    • v.10 no.2
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    • pp.75-82
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    • 2006
  • 세계적인 환경 보호 정책에 따라 할로겐화탄소 냉매를 대체할 환경 친화적인 초저온 냉매의 개발과 연구가 활발히 진행되고 있다. 일반적으로 캐스캐이드 2원 냉동 시스템에서 아직까지 할로겐화탄소 냉매가 널리 사용되고 있다. 탄화수소 화합물의 한 종류인 에탄은 낮은 지구 온난화 지수와 낮은 오존층 파괴지수를 가진 친 환경적인 자연 냉매이다. 본 연구는 지구 온난화 지수가 높은 R-23 냉매와 비교하여 캐스캐이드 2원 냉동 시스템에서 에탄의 성능 시험을 목적으로 수행 하였다. 1원측에는 R-22를 사용하였으며, 증발 온도에 따른 성능은 R-23 보다 에탄(R-170)이 더 높게 나타났다.

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An Analysis of Korean University Library Holdings of Western Language Books Using a Union Catalog Database (종합목록DB를 이용한 국내 대학도서관 서양서 소장 실태 분석)

  • Lee, Ji-Won;Lee, Jae Yun
    • Journal of the Korean Society for information Management
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    • v.35 no.1
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    • pp.205-229
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    • 2018
  • This study analyzed Korean university libraries' holdings of Western language books published in 2003 and 2013 using the KERIS union catalog with a view to investigating the changes in collection development of Western language books in the libraries. To do that, new collection indexes - holding h-index, CUI (Collection Uniqueness Index), and CCHR (Common Collection Holding Ratio) - were suggested, and they were used with basic indexes such as the number of titles, the number of books, and the number of books per title. The analysis reveals that compared to those published in 2003, the number of titles was decreased by 16.1% with those published in 2013, and the number of books dropped more sharply, by 42.2%. Also, in 2013, CCHR was decreased while CUI was increased. In terms of subject, among DDC main classes, 0XX (Generalities) showed the greatest decrease rate in both the number of titles and books because of the radical reduction of computer-related books. In terms of each library's holdings, the number of Western language books held by top libraries has been increased with those published in 2013.

Analysis of the Relationship Between Freight Index and Shipping Company's Stock Price Index (해운선사 주가와 해상 운임지수의 영향관계 분석)

  • Kim, Hyung-Ho;Sung, Ki-Deok;Jeon, Jun-woo;Yeo, Gi-Tae
    • Journal of Digital Convergence
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    • v.14 no.6
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    • pp.157-165
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    • 2016
  • The purpose of this study was to analyze the effect of the shipping industry real economy index on the stock prices of domestic shipping companies. The parameters used in this analysis were the stock price of H Company in South Korea and shipping industry real economy indices including BDI, CCFI and HRCI. The period analysis was from 2012 to 2015. The weekly data for four years of the stock price index of shipping companies, BDI, CCFI, and HRCI were used. The effects of CCFI and HRCI on the stock price index of domestic shipping companies were analyzed using the VAR model, and the effects of BDI on the stock price index of domestic shipping companies were analyzed using the VECM model. The VAR model analysis results showed that CCFI and HRCI had negative effects on the stock price index, and the VECM model analysis results showed that BDI also had a negative effect on the stock price index.

Evaluation for Rock Cleavage Using Distribution of Microcrack Spacings (II) (미세균열의 간격 분포를 이용한 결의 평가(II))

  • Park, Deok-Won
    • The Journal of the Petrological Society of Korea
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    • v.25 no.2
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    • pp.151-163
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    • 2016
  • The characteristics of the rock cleavage in Jurassic granite from Geochang were analysed. The evaluation for the three directions of rock cleavages was performed using the parameters such as (1) frequency of microcrack spacing(N), (2) total spacing(${\leq}1mm$), (3) mean spacing($S_{mean}$), (4) difference value($S_{mean}-S_{median}$) between mean spacing($S_{mean}$) and median spacing($S_{median}$), (5) density of spacing(${\rho}$), (6) difference value between two exponents for the whole range of the diagrams(${\lambda}_H-{\lambda}_L$), (7) mean value of exponent(${\lambda}_M$), (8) mean value of exponential constant($a_M$), (9) difference value between two exponents for the section under the initial points of intersection(${\lambda}t_H-{\lambda}t_L$), (10) mean value of exponent(${\lambda}t_M$) and (11) mean value of exponential constant($at_M$). The results of correlation analysis between the values of parameters for three rock cleavages and those for three planes are as follows. The values of (I) parameters(1, 2, 7 and 8) and (II) parameters(3, 4 and 5) are in orders of (I) H(hardway, (H1 + H2)/2) < G(grain, (G1 + G2)/2) < R(rift, (R1 + R2)/2) and (II) R < G < H. On the contrary, the values of the above two groups(I~II) of parameters for three planes show reverse orders. Besides, the values of parameter $6({\lambda}_H-{\lambda}_L)$, parameter $9({\lambda}t_H-{\lambda}t_L)$, parameter $10({\lambda}t_M)$ and parameter $11(at_M)$ for three planes are in orders of R(rift plane, (G1 + H2)/2) < H(hardway plane, (R2 + G2)/2) < G(grain plane, (R1 + H2)/2), H < G < R, H < R < G and R < H < G, respectively. The values of the above four parameters for three rock cleavages show the various orders of R < H < G, R < H < G, H < G < R and H < G < R, respectively. Meanwhile, the spacing values equivalent to the initial points of contact and intersection between the two directions of diagrams were derived. The above spacing values for three rock cleavages are in order of rift(R1 and R2) < grain(G1 and G2) < hardway(H1 and H2). The spacing values for three planes are in order of rift plane(G1 and H1) < hardway plane(R2 and G2) < grain plane(R1 and H2). In particular, the intersection angles for three rock cleavages and three planes are in order of rift and rift plane < hardway and hardway plane < grain and grain plane. Consequently, the two diagrams of rift(R1 and R2) and rift plane(G1 and H1) show higher frequency of the point of contact and intersection. These characteristics of change were derived through the general chart for three planes and three rock cleavages. Lastly, the correlation analysis through the values of parameters along with the distribution pattern is useful for discriminating three quarrying planes.

Evaluation for Rock Cleavage Using Distribution of Microcrack Lengths (미세균열의 길이 분포를 이용한 결의 평가)

  • Park, Deok-Won
    • The Journal of the Petrological Society of Korea
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    • v.24 no.3
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    • pp.165-180
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    • 2015
  • Jurassic granite from Geochang was analysed with respect to the characteristics of the rock cleavage. The phases of distribution of microcracks were well evidenced from the enlarged photomicrographs(${\times}6.7$) of the thin section. In this study, the length - cumulative frequency diagrams were used for expressing the distribution characteristics of microcrack. The diagrams for the six directions were arranged in the magnitude of density(${\rho}$). These diagrams show an order of H2 < H1 < G2 < G1 < R2 < R1 from the related chart. Among six diagrams, the diagram for hardway 2(H2) occupies the lowermost region on the left. On the contrary, the diagram for rift 1(R1) occupies the uppermost region on the right. Curve patterns of the two diagrams change from uniform to exponential distribution type in accordance with the increased density. The overall distribution characteristics of the diagrams were well evidenced from the magnitude of the exponent(${\lambda}$) and length of line oa related to the exponential straight line. The magnitude of exponent governing the values of slope(${\theta}$) is inversely proportional to the values of microcrack parameters such as number(N), length(L) and density. On the contrary, length of line oa is directly proportional to the values of the above three parameters. Above microcrack parameters related to the order of arrangement of diagrams show an order of hardway(H1 + H2) < grain(G1 + G2) < rift(R1 + R2). The distribution characteristics of progressive variation are found among the six diagrams. The order of arrangement of the diagrams indicates a relative magnitude of the rock cleavage. Meanwhile, the parameters such as slope, exponent, density and length of line oa were arranged in an order of H2 < H1 < G2 < G1 < R2 < R1. The variation curves of a smooth quadratic function are shown from the related chart. From the correlation chart between density and the above parameters, a common regularity following power-law correlation function was derived. Finally, the analysis for the rock cleavage was conducted through the combination between the diagram and microcrack parameter. This type of combination contribute to the progressivity in evaluation for the rock cleavage.

A Study on Attenuation of Ground Vibration Using Hammer Generated Seismic Wave (탄성파탐사에 의한 토양층 지반진동의 감쇠연구)

  • 서만호;손호웅
    • The Journal of Engineering Geology
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    • v.6 no.2
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    • pp.95-102
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    • 1996
  • A study on the attenuation of ground vibration was carried out on the soil layer using seismic exploration method. A 12-channel engineering seismograph was used to acquire real digital amplitude data in field work. Frequency analysis of seismic data shows maximum spectrum amplitude around 40Hz. Relative amplitude decreases exponentially as the distance increases and the attenuation factors are n = 0.25 and a = 0.13-0.20. Internal attenuation indexes(a) are 0.13 and 0.20 in the wet soil zone and the vegatated soil zone, respectively. It means that ground vibration attenuates faster in vegatated soil zone than in wet soil zone. Average internal attenuation coefficient(h) was determined to be 0.094 from seismic velocity and frequency analysis.

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The Mechanism for the Low Temperature Crystallization of Amorphous Silicon Produced under Three Different Conditions (세가지 다른 조건으로 형성시킨 비정질 실리콘에 대한 저온 열처리 결정화 기구)

  • Lee, Jae-Gap;Jin, Won-Hwa;Lee, Eun-Gu;Im, In-Gwon
    • Korean Journal of Materials Research
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    • v.6 no.3
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    • pp.309-317
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    • 1996
  • 세가지 다른 방법을 이용하여 형성시킨 비정질 실리콘(SiH4 a-Si, Si2H6 a-Si, Si+ implanted SiH4 a-Si)들에 대한 저온 결정화 기구의 차이를 고전적 이론인 Avrami 식(X=1-exptn, X=결정화 분율, t=열처리 시간, n=지수)을 이용하여 검토하였다. Silane으로 형성된 비정질 실리콘의 결정화 과정에서는 Avrami 식에서의 n의 값이 2.0을 나타내고 있어, 결정성장이 이차원적으로 이루어지면서 핵생성률이 시간에 따라 감소하고 있음을 알 수가 있었다. Si+ 이온 주입에 의하여 형성된 비정질 실리콘의 결정화에서는 3.0의 지수 값이 얻어지고 있어, 정상상태의 핵생성과 함께 2차원적인 결정 성장이 이루어지고 있었다. Disilane으로 형성된 비정질 실리콘에 대한 결정화에서는 2.8의 지수값이 얻어져, 정상상태의 핵 생성이 우세하게 일어나는 2차원적인 결정성장이 일어나고 있음을 알 수 있었다. 또한 TEM을 이용하여 시간에 따라 변하는 핵생성률을 조사하여, Avrami 식의 적용이 타당성 있음을 증명하였다. 마지막으로, 최종 입자의 크기가 열처리 온도에 크게 영향을 받고 있지 않음을 확인하였다.

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Estimation of Site Index and Stem Volume Equations for Larix leptolepis Stand in Jinan, Chonbuk (전북 진안 낙엽송 임분의 지위지수 및 간재적식 추정)

  • Jeon, Byung-Hwan;Lee, Sang-Hyun;Lee, Young-Jin;Kim, Hyun;Kang, Hag-Mo
    • Journal of Korean Society of Forest Science
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    • v.96 no.1
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    • pp.40-47
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    • 2007
  • The objectives of this study were to derive site index and stem volume prediction equation based on stem analysis data for Larix leptolepis in Jinan region. The function for site index was developed by algebraic difference equation method. Polymorphic site index family curves with base age of 40 were presented based on the Schumacher height equation. The best stem volume prediction equation was suggested as $V=0.00260+0.00000399D^2H$. The simultaneous F-test using this equation showed that the estimated tree stem volumes were not significantly different (${\alpha}=0.05$ level) from the observed stem volumes for model evaluation. Therefore, site index and volume prediction equations prepared in this study could provide an indication of site quality and basic information for making of yield table, and could be used for rational forest management of Larix leptolepis stands grown in Jinan region.