• Journal of Korean Society of Transportation
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• v.36 no.3
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• pp.203-215
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• 2018

This study suggests a method to construct large scale dynamic O/D reflecting the characteristic that the passengers' travel patterns change according to the land use patterns of the destination. There are limitations in the existing research about dynamic O/D estimation method, such as the difficulty of collecting data, which can be applied only to a small area, or limiting to a specific transportation network such as highway networks or public transportation networks. In this paper, we propose a method to estimate dynamic O/D without limitation of analysis area based on transportation resources that can be easily collected and used according to the big data era. Clustering analysis was used to calculate the departure time trip distribution ratio based on arrival time and departure time trip distribution function was estimated by each cluster. As a result of the comparison test with the survey data, the estimated distribution function was statistically significant.

• Journal of the Korean Society of Child Welfare
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• no.36
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• pp.65-99
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• 2011

The main purpose of this study is to analyze the relationship between child poverty rate and family policy expenditure of welfare states (focusing on OECD countries). We analyzed not only the total social & family policy expenditures but the components of the family policy expenditure. OECD SOCX and calculated data from the LIS & OECD data were utilized for child and family policy expenditures and the poverty rate. One-way correlation and cluster analysis were employed for the analysis. The analytic results are as follows: Southern European and Anglo-Saxon countries' child poverty rates were higher and Scandinavian countries' child poverty rates were lower than any other clusters. The countries with high child poverty rate had higher child poverty rate than the entire nation's poverty rate, but Scandinavian countries' child poverty rate was lower. There was a strong correlation between family policy expenditure and child poverty rate. Especially the service expenditure and leave benefit expenditure were highly correlated with child poverty rate. On the other hand, cash expenditure was not significantly correlated with child poverty rate. We can suggest the policy implications from these results. Based on the analytic results, policy implications that the government should increase the family policy budget, especially the budget for family services and leave benefit to decrease child poverty rate and should make effort to support the employment of parents through policies such as active labor market strategies can be suggested.

• 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.

• Journal of the Korean Society for information Management
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• v.34 no.1
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• pp.51-71
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• 2017

This study conducted a survey to measure recognition distance between the materials which are located separately in a children's library targeting 200 elementary school lower grade students, higher grade students, and school parents(adults). And compared recognition distance between the elements of materials of individual visitor group with multidimensional scaling and K-mean group analysis. Multidimensional Scaling (MDS) is a technique for projecting the cognitive state in space by evaluating the similarity or attribute of the analysis target. Even though it is mainly used for market diagnosis in marketing, It can also be applied to present an ideal physical layout plan by analyzing the distance. As a result of analysis, the main discoveries are as follows. First, elementary school students cognize child, baby and computer materials should be adjacent as a same group. But recognition of adults(school parents) is reflected by differing from elementary school students vastly. They cognize that computer materials should be formed as a special group separated from child and baby's materials. Second, elementary school higher graders and adults(school parents) groups also want to separate their main reading materials from baby's book, therefore They both want to secure silent reading space separating from baby. Third, as a result to confirming how this recognition distance system of materials is reflected in a real children's library through three children's libraries in Y-gu, Incheon, there is no library with structure according perfectly with a recognition system of a particular class, but a recognition system of adults and elementary school students is partially reflected because baby, child and computer materials, and baby and child materials are commonly separated and placed. It is difficult to insist that a recognition system of a visitor group, especially a recognition system of children is absolute consideration conditions in material placement of a children's library. However, understanding cognition of the user groups can be an important evidentiary factors to offer differentiated service space according to visitors and effective placement of the elements of library resources.

• Journal of Korean Society of Transportation
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• v.17 no.3
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• pp.21-30
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• 1999

One of the major tasks of a Police station is the management of road traffic accidents. Each police station is responsible for keeping Traffic Accident Records (TAR) which can be used as the basis of statistical analyses. Results of such statistical analyses have been applied to establishing effective traffic Plans and safety Policies at the macro level. In this Paper, we apply QFD in a way that each police station can set and implement specific policies according to the local characteristics. Cluster analysis is employed to find black spots in each local area. Poisson repression is used to identify the area specific factors related to various types of road accidents. Results of such statistical analyses are applied to QFD. Our approach is expected to contribute to reduce various types of area specific road traffic accidents.

• Korean Journal of Environmental Biology
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• v.34 no.1
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• pp.41-47
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• 2016

The phytosociological study was carried out to investigate the structural characteristics of coastal vegetaion in South Korea. The vegetation data of total 102 sites were analyzed by the $Z{\ddot{u}}rich$-Montpellier school's method. Eleven community of coastal vegetation were recognized : Vitex rotundifolia-Rosa wichuraiana community, Calystegia soldanella community, Carex kobomugi-Elymus mollis community, Zoysia sinica community, Suaeda maritima community, Suaeda australis community, Suaeda glauca-Atriplex gmelinii community, Suaeda japonica community, Phragmites communis community and Calamagrostis epigeios community. Principal componant analysis (PCA) showed the similar result with phytosoiological classification.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1745-1749
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• 2010

하천 내 설치하는 수제는 제방보호 및 유로변경의 목적으로 하천내 시공되는 구조물 중의 하나로서 하천복원과정에 있어 필수불가결한 구조물 중의 하나로 인식되고 있다. 수제는 대개 하나 이상의 일련의 군집형태로 수로 자체의 특성을 고려하여 설치가 되고 있다. 그러나 이러한 수제의 무분별한 설치는 주변 경관을 저해하는 요소로 나타날 수 있을 뿐만 아니라 시공에 따른 비용에 적지 않은 부담을 야기 시키기 충분하다. 그러나 적절한 간격 조절을 통해 생태, 호안보호, 경관 등의 수제의 기능을 만족한다면 이보다 더 효율적인 것을 없을 것이다. 따라서 본 연구에서는 수제간격에 따른 하상변동 실험을 통해 효율적인 배치간격을 제시할 목적으로 수행되었다. 실험은 폭 1.2m, 길이 50m, 높이 1.5m 인 직선수로에서 수로폭의 15%길이를 갖는 연직수제를 2개를 대상으로 각각 수제길이의 2~8배의 간격 조절을 통해 하상변동실험을 수행 하였다. 실험용입자는 중간입경($d_{50}$)이 0.15mm 인 모래를 사용하였으며 6시간 동안 통수하였다. 실험결과 유수에 의해 첫 번째 설치된 수제에서 지배적으로 많은 영향을 받게 되면서 후면부에 설치된 수제는 비교적 영향을 덜 받고 있었다. 그러나 그 영향권을 점차 벗어나게 되면서 수제 간격이 4배 이상일 경우 후면부 수제에서도 세굴이 발생하고 있음을 확인할 수 있었다. 이러한 자료는 추후 수제설치에 따른 효율적인 배치 간격 결정에 중요한 자료로 이용될 수 있을 것이다. 그러나 수제들이 시공되는 대다수의 하천들은 어느 정도의 만곡도를 갖고 있기 때문에 이를 간과해서는 않될 것으로 판단된다.

• Journal of the Korean Society for Library and Information Science
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• v.31 no.2
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• pp.139-175
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• 1997

This study attempts to assess university library organizational effectiveness and to develop an instrument to measure the construct. Major findings of the study are as follows. First, organizational effectiveness criteria can be reduced to fifteen factors. Second, four distinct clusters of libraries are identified, each showing a unique effectiveness profile. Third, there are significant differences in dimensions of organizational effectiveness according to the number of users, full-time staff, unit and position to which respondents belong. The investigation shows that organizational effectiveness of university libraries is, indeed, a multidimensional construct, implying that no single measure of effectiveness Is sufficient to describe an organization.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.113-113
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• 2018

본 연구는 다목적 입자군집최적화(Particle Swarm Optimization, PSO) 알고리즘을 SWAT(Soil and Water Assessment Tool) 모형에 적용하여 자동보정 알고리즘의 적용 가능성을 평가하고자 한다. PSO 알고리즘은 Python을 활용해 다목적 함수를 고려할 수 있도록 새롭게 개발되었다. SWAT 모형의 유출 해석은 안성천의 공도 수위 관측소 상류유역($366.5km^2$)을 대상으로 하였으며, 공도 지점의 2000년부터 2017년까지의 일 유량 자료를 이용하여 검보정하였다. 모형을 위한 기상자료는 공도유역 주변 3개 기상관측소(수원, 천안, 이천)의 일별 강수량, 최고 및 최저기온, 평균 풍속, 상대습도 및 일사량을 구축하였다. SWAT 모형의 유출 해석은 결정계수(Coefficient of determination, $R^2$), RMSE(Root mean square error), Nash-Sutcliffe 모형효율계수(NSE) 및 IOA(index of agreement) 등을 활용하여, 기존 연구 결과와 PSO 알고리즘을 활용한 결과를 비교 분석하고자 한다. 본 연구에서 개발한 다목적 PSO 알고리즘을 활용한 SWAT모형의 유출 해석은 보다 높은 정확도를 얻을 수 있을 것으로 예상되며, Python으로 개발되어 SWAT모형 이외에도 널리 적용될 수 있을 것으로 판단된다.

• The Korean Journal of Financial Management
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• v.24 no.3
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• pp.63-89
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• 2007

This study aims at empirically verifying whether long memory properties exist in returns and volatility of the financial time series and then, empirically observing influential factors of long-memory properties. The presence of long memory properties in the financial time series is examined with the Hurst exponent. The Hurst exponent is measured by DFA(detrended fluctuation analysis). The empirical results are summarized as follows. First, the presence of significant long memory properties is not identified in return time series. But, in volatility time series, as the Hurst exponent has the high value on average, a strong presence of long memory properties is observed. Then, according to the results empirically confirming influential factors of long memory properties, as the Hurst exponent measured with volatility of residual returns filtered by GARCH(1, 1) model reflecting properties of volatility clustering has the level of $H{\approx}0.5$ on average, long memory properties presented in the data before filtering are no longer observed. That is, we positively find out that the observed long memory properties are considerably due to volatility clustering effect.