• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.424-424
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• 2019

수질오염 저감을 위한 유기물질의 처리를 위해 생물학적 처리에 중점을 둔 하 폐수 처리시설의 증가에 따라 BOD로 대표되는 생분해성 유기물질은 꾸준히 감소하였으나, COD농도의 경우 뚜렷한 감소를 보이지 않고 있다. 유기물질 중 특히 난분해성 물질의 증가는 상수원으로 사용되는 하천의 경우 조류 증식 등을 유발하고 여과공정에 영향을 미쳐 상수처리의 효율을 떨어뜨리는 등의 환경적인 문제를 야기할 수 있다. 기존 BOD, COD로 대표되는 유기물질의 경우 각 유기물질별 상관관계 및 유출특성 등에 대한 연구는 많이 이루어졌으나, 난분해성 물질에 대한 조사는 상대적으로 미진한 실정이다. 특히 동진강수계는 '새만금 제2단계 수질개선종합대책' 등 장기적인 수질개선 대책들이 추진되면서 하천의 BOD5 및 TP는 감소추세를 보이고 있으나, COD는 개선되지 않고 증가하는 추세를 보이고 있다. 동진강의 말단부의 경우 COD/BOD5의 비율이 지속적으로 증가하는 추세를 보이고 있어 상대적으로 난분해성 유기물질에 대한 관리의 중요성이 대두되고 있다. 이러한 COD 및 COD/BOD5의 증가 추세는 국내 4대강에서 전반적으로 나타나고 있는 추세로서, 정부는 2013년부터 하천 및 호소의 생활환경기준에 TOC 항목을 도입하여 2016년부터 호소환경기준의 대표항목을 COD에서 TOC로 대체하였으며, 폐수배출시설에 대해서도 점차적으로 확대 적용할 계획으로, 난분해성물질을 포함하는 총유기물질 관리를 위해서 수질 및 수생태계 환경기준에서 유기물질에 대한 환경기준을 BOD5와 COD에서 TOC로 변경하는 정책을 추진 중에 있다. 본 연구에서는 동진강 유역의 본류 및 지류에서 TOC등 유기물질의 시공간적인 분포와 오염원별 배출특성을 현장조사를 통해 조사 분석하였다. 조사 시기는 건기시, 강우시로 구분하여 수행하였으며 조사항목은 일반수질항목, 유기물질 항목, 유기물질 성상 분석 등에 대하여 수행하였다. 난분해성물질 관리를 위한 기초자료확보를 통하여 새만금호의 수질개선 및 목표수질 달성에 기여 할 것으로 판단된다.

• The Korean Journal of Applied Statistics
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• v.35 no.3
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• pp.371-384
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• 2022

The fused LASSO signal approximator (FLSA) can be applied to find change points from the data having piecewise constant mean structure. It is well-known that the FLSA is inconsistent in change points detection. This inconsistency is due to a total-variation denoising penalty of the FLSA. ℓ₁ trend filter, one of the popular tools for finding an underlying trend from data, can be used to identify change points of piecewise linear trends. Since the ℓ₁ trend filter applies the sum of absolute values of slope differences, it can be inconsistent for change points recovery as the FLSA. However, there are few studies on the inconsistency of the ℓ₁ trend filtering. In this paper, we demonstrate the inconsistency of the ℓ₁ trend filtering with a numerical study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1B
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• pp.71-80
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• 2010

This study aimed to figure out the effect of urbanization on meteorological variables (air temperature, wind speed, relative humidity, solar radiation and precipitation) and reference evapotranspiration (RET). The research area of 6 urban areas and 6 rural areas near each urban area was selected. The monthly average daily data were collected from 12 ground stations operated by Korea Meteorological Administration (KMA) and the changes in climate variables were analyzed. Results of annual analysis have shown that the reference evapotranspiration (RET) tends to increase in urban areas while decreasing in rural areas. In particular, due to rising RET in urban areas and decreasing RET in rural areas, we can infer that the urbanization has affected to the RET. Results of monthly analysis showed that the urbanization has effects on the RET of July compared to other months (January, April and October). The yearly and monthly effects of urbanization on RET were closely related to solar radiation, relative humidity and change in temperature, and related to wind speed.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.87-97
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• 2014

City is currently developing into intelligent city which adopts the ICT technology to resolve the problems and increase the competitiveness. This intelligent city is promoted under the name of U-City or Smart City, yet it is also criticized in the trend for what the differences between U-City and Smart City are. In this study, we draws the differences between U-City and Smart City from our distinctive research method, text mining which analyzes the trend of research papers, and contribute to direction of U-City study in the future. Through this analysis, the study results in that U-City focuses practical implementation in domestic cities while Smart City focuses technological development and provision of single service. However, this paper has a limitation as the subjective opinion was reflected to configure the sets of keywords, and only keywords and s were analyzed. Therefore, further studies are needed to confirm the differences between U-City and Smart City with related research papers and reports.

• The Korean Journal of Applied Statistics
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• v.29 no.5
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• pp.935-947
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• 2016

This paper considers the analysis of patterns in meteorological research and development using a text-mining algorithm as the method of analyzing unstructured data. To analyze text data, we define a list of terms related to meteorological research and development, construct times series of a term-document matrix through data preprocessing, and identify terms that have upward or downward patterns over time. The proposed methodology is applied to multi-year plans funded by Korea Meteorological Administration research and development programs from 2011 to 2015.

• The Korean Journal of Applied Statistics
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• v.36 no.6
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• pp.573-589
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• 2023

In a piecewise linear trend model, the change points coincide with the mean change points of the first differenced time series. Therefore, by detecting the mean change points of the first differenced time series, one can estimate the change points of the piecewise linear trend model. In this paper, based on this fact, a method is proposed for detecting change points of the piecewise linear trend model using the simple moving average of the first differenced time series rather than estimates of the slope or residuals. Our Monte Carlo simulation experiments show that the proposed method performs well in estimating the number of change points not only when the error terms in the piecewise linear trend model are independent but also when they are serially correlated.

• The Korean Journal of Applied Statistics
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• v.10 no.1
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• pp.163-175
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• 1997

Randomization of the run order within a block is a technique commonly employed by the experimenters of block designs to avoid biases in the estimates of the effects of interest. In practice, however the experimental responses are sometimes affected by the spatial or temporal position of the experimental units within a block. In such cases, it is preferable to use a systematic ordering of the treatments. It is often possible to find an ordering which will allow the estimation of treatment effects independently of any trend is known as a trend-free block designs. In many idustrial and agricultural experiments, treatments are applied to experimental units sequentially in time or space. This paper begins with a review of concepts and properties of trend-free designs. We, then devise algorithms to generate linear trend-free designs. We extend and modify the existing algorithm which is given by Bradley and Odeh(1988). Also, the algorithm which generate all possible linear trend-free designs in provided.

• The Korean Journal of Applied Statistics
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• v.11 no.2
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• pp.221-232
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• 1998

There was a large reform in administrative districts during 1990-95, which might influence the estimates of migration according to the definition of migration. An indirect method has been worked out in this paper to measure the influence of the district reforms on migration estimation and to provide more accurate recent trend of migration. The district reform during 1950-95 tended to decrease the estimate of total migrants and influenced substantially the estimates of migrants between urban and rural. When the influences of district rewarm were removed, it was found that total migrations increased by 8.5%, between two periods 1985-'90 and 1990-'95, and the net migrants in the rural areas reduced drastically. It was also found that the change in migration trend between urban and rural was no more a local but a nation wide phenomenon.

• The Journal of Sustainable Design and Educational Environment Research
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• v.15 no.1
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• pp.30-39
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• 2016

Students receiving plan is not based on short-term indicators, such as student-centered, student-induced factor to address school needs new complaint, it is necessary to establish the school in the center of a long-term (30 years) perspective. Therefore, analysis of Cheongju students can examine the entire 30 years of the elementary school in this study are as follows: First, given the increasing number of students in seven models and presented the case to its types. Second, considering the geographical characteristics and the development of regional characteristics classify 55 elementary Schools in Cheongju City by dividing the number of students increase or decrease trend to 10 zones the results are as follows: Students Number increasing school group of 4 schools, 15 schools students Number fell in shot Term, the Students Number dropped in middle Term 26 schools, 10 was a small school. In particular, it is urgently necessary to establish measures for these small schools. Third, despite the reduced number of students indicated in the analysis result, caused the social conflict factors by excessive new school requirements. It also caused a number of students from schools when the Curve of Students Number are to remain flat or decline. It shows that no additional new demand of School in the region. Fourth, the number of students increasing trend forecasting model

• Journal of Korean Library and Information Science Society
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• v.41 no.4
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• pp.35-50
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• 2010

The purpose of this study was to analyse the ralative efficiency of 15 public libraries over a time period(2006-2008) by Data Envelopment Analysis(DEA). The selected input variables were total staff, total area and total holdings. And the selected output variables were total circulations and total user. The results are as followed. First, a technical efficiency trend of public libraries has been improved since 2006. Second, a technical efficiency increase can be explained by increase of a pure technical and scale efficiency both.