• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.6
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• pp.722-728
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• 2012

Urban sewer systems has a limitation of capacity of rainwater storage and problem of occurrence of untreated sewage, so adopting a storage facility for sewer flooding prevention and urban non-point pollution reduction has a big attention. The Korea Ministry of Environment has recently introduced a new concept of "multi-functional storage facility", which is crucial not only in preventive stormwater management but also in dealing with combined sewer overflow and sanitary sewer discharge, and also has been promoting its adoption. However, reserving a space for a single large-scale storage facility might be difficult especially in urban areas. Thus, decentralized construction of small- and midium-sized storage facilities and its operation have been introduced as an alternative way. In this paper, we propose a model predictive control scheme for an optimized operation of distributed storage facilities and sewer networks. To this aim, we first describe the mathematical model of each component of networks system which enables us to analyze its detailed dynamic behavior. Second, overflow locations and volumes will be predicted based on the developed network model with data on the external inflow occurred at specific locations of the network. MPC scheme based on the introduced particle swarm optimization technique then produces the optimized the gate setting for sewer network flow control, which minimizes sewer flooding and maximizes the potential storage capacity. Finally, the operational efficacy of the proposed control scheme is demonstrated by simulation study with virtual rainstorm event.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.6
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• pp.706-714
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• 2012

The Korea Meteorological Administration provided the recent four-years records of weather dataset for our very short-term heavy rainfall prediction. We divided the dataset into three parts: train, validation and test set. Through feature selection, we select only important features among 72 features to avoid significant increase of solution space that arises when growing exponentially with the dimensionality. We used a differential evolution algorithm and two classifiers as the fitness function of evolutionary computation to select more accurate feature subset. One of the classifiers is Support Vector Machine (SVM) that shows high performance, and the other is k-Nearest Neighbor (k-NN) that is fast in general. The test results of SVM were more prominent than those of k-NN in our experiments. Also we processed the weather data using undersampling and normalization techniques. The test results of our differential evolution algorithm performed about five times better than those using all features and about 1.36 times better than those using a genetic algorithm, which is the best known. Running times when using a genetic algorithm were about twenty times longer than those when using a differential evolution algorithm.

• Korean Journal of Construction Engineering and Management
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• v.9 no.3
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• pp.206-213
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• 2008

Due to the following reasons, the management of curtain wall parts and material is very Important. Firstly, curtain wall work is one of the main works in High-rise building construction for it takes about $10{\sim}15%$ of the total construction cost. Secondly, the whole process of curtain wall work including manu acture, delivery, storage, installation and maintenance is very complicated and sometimes more than 30 companies involve in the process. Thus there are many control points for curtain wall units. Thirdly, there are not enough space on site for material storage and this situation is more serious for sites in urban area. The purpose of this research is to validate an information systems using RFID technology that is developed to manage the curtain wall units following the process of curtain wall work. For the validation, the cycle times of curtain wall work before and a ter the system was used. The results show that using the systems shorten the cycle time of the curtain wall work. Thus it is concluded that the system can increase the efficiency of managing curtain wall work.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.21 no.3
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• pp.151-163
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• 2010

It is necessary, due to changes in the information environment, to investigate problems in existing information retrieval systems. Ontologies and social tagging, which are a relatively new means of information organization, enable exploratory discovery of information. These two connect a thought of a user with the thoughts of numerous other people on the Internet. With these connection chains through the interactions, users are foraging information actively and exploratively. Thus, the purpose of this study is, through qualitative research methods, to identify numerous discovery facilitators provided by ontologies and social tagging, and to create an exploratory discovery model based on them. The results show that there are three uppermost categories in which 5, 4 and 4 subcategories are enumerated respectively. The first category, 'Browsing and Monitoring,' has 5 sub categories: Noticing the Needs, Being Aware, Perceiving, Stopping, and Examining a Resource. The second category, Actively Participating, has 4 categories: Constructing Meaning, Social Bookmarking and Tagging, Sharing on Social Networking, Specifying the Original Needs. The third category, Actively Extends Thinking, also has 4 categories: Social Learning, Emerging Fortuitous Discovery, Creative Thinking, Enhancing Problem Solving Abilities. This model could contribute to the design of information systems, which enhance the ability of exploratory discovery.

• Korean Journal of Social Welfare Studies
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• v.47 no.1
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• pp.57-92
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• 2016

The Correlations Between the Labour Market Structure and Poverty of the Regions The main objectives of this study are to make an investigation into the spatial characteristics of poverty and to analyze the effects of regional labour market structure. Most previous studies on poverty were more likely to examine internal factors like the characteristics of poor households or family structures than external factors in terms of the regional environments. In order to achieve these goals, this study used the Small Area Estimation designed to estimate the income of each household and then calculate the poverty rate of each local area in order to examine the spatial characteristics of poverty. The poverty distribution in Korea showed the local labour market structures effect on the region poverty rate. The Korean economy now exhibits a big gap between the haves and the have-nots and between urban areas and rural areas. The poverty rate of particular regions will increase and those in the areas will face deteriorated circumstances falling into poverty traps. This study reflects this stern reality and empirically proved the strong need for consideration of regional characteristics in conducting studies on poverty and related policy amendments.

• Korean Journal of Comparative Education
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• v.28 no.3
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• pp.333-354
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• 2018

The study aimed to compare and analyze Nuri curriculum and contents for mathematics in Korea and the Common Core State Standards(CCSS) and New Jersey Preschool Standards for mathematics in the United States. With the results as basis, this study intended to provide suggestions and directions for improving Nuri curriculum of mathematics for young children. For the goal of this study, educational goals, categories of contents, and specific contents were reviewed. First, results of this study indicated that Nuri curriculum for mathematics provides comprehensive educational goals that promote problem-solving ability in everyday contexts with composing mathematical knowledge. On the contrary, CCSS and Preschool Standards provide specific educational goals that focus on children's mathematical skills and concepts. Second, the contents of both countries' curriculum concentrate on 'counting and cardinality', 'measurement', and 'spatial and geometric sense.' There are 5 categories of CCSS, 4 categories of Preschool Standards based on CCSS and one category of Nuri curriculum for mathematics. Third, there are the differences between the two countries' curriculum in continuity from kindergarten to first grade and description method for curriculum.

• Korean Journal of Social Welfare Studies
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• v.44 no.3
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• pp.31-56
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• 2013

The purpose of this study was to investigate the changes that family caregivers have experienced since using the Korean Long-Term Care Insurance(LTCI) system. In-depth interviews were conducted to determine how the services offered within the LTCI program had affected family caregiving and what changes they had incurred. Results from the qualitative content analysis show that the LTCI program significantly reduced the caregiving burden among family caregivers although burdens that family caregiver perceived varied greatly depending on the types of service that the family selected, and assigned family caregivers different identities and diverse roles(i.e., service user, family caregiver, certified care provider) depending on the service they use. The phenomenon of 'certified family care provider', which was not an intention of LTCI, demonstrates the practical need of elderly persons who require both care and the comfort of family and economic status of the family. Despite the positive impact of the LTCI policy on the family caregivers' burden and family relationship, the current LTCI system should be modified in order to better meet the needs of beneficiaries and their family caregivers.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.509-509
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• 2015

물 수요관리측면에 대한 정책을 수립하기 위해서는 현재 또는 장래에 대한 용수수급의 정확한 이해를 필요로 한다. 이를 위해서는 용수 수요량 및 공급량뿐만 아니라 여러 산정요소를 필요로 하는데, 그 중 회귀수량은 물이 이용되고 다시 하천으로 회귀되어 이용될 가능성이 있는 수량으로 정의되며, 용수수급 및 용수절약 측면에서 회귀 수량은 중요한 요소라 할 수 있다. 회귀수량 조사는 유역조사 사업 이래, 10년간 생?공용수를 중심으로 미시적, 거시적으로 조사를 시행하였으나, 측정 자료의 신뢰도, 조사방법 및 지점선정 등의 문제로 인하여 조사 성과의 활용성이 매우 낮은 실정이다. 수자원장기종합계획등에서는 수자원관련 계획 수립시 생?공용수의 회귀율을 65 %로 적용하고 있으나, 이는 1970년대 말의 사회적 여건 및 경제적 상황이 반연된 결과로 현재 상황에 적용되기 곤란하다. 따라서, 현재 실정에 맞는 회귀율 산정은 반드시 필요하게 된다. 본 연구에서는 기존 생활용수 회귀수량 산정 연구 한계를 보완하고 유역조사 시행을 위한 개선된 회귀수량을 산정하고자 한다. 본 연구는 서울시 중랑물재생센터 처리구역을 기반으로 중랑천유역을 시험유역으로 선정하였다. 기존 회귀수량 산정방법을 개선하기 위해 시험유역 회귀수량 산정을 위한 가용 자료 분석 및 용수흐름 네트워크 공간분석을 추가로 진행하였다. 가용자료로 시험 유역내 상수공급자료(정수장 공급량, 상수계통도, 유수 및 누수율), 하수처리자료(하수처리구역도, 하수처리계통도, 유입량 및 방류량) 및 기상자료(기상청 지점 및 AWS 강우자료)를 구축하였고 각각의 상수계통도 및 하수처리계통도로부터 용수 흐름 네트워크망을 구축하였다. 상수공급자료로부터 상수계통도 공급지역을 구분하여 월별 유수율에 따른 월별 실 공급량을 산정하였다. 하수처리자료로부터 시험유역에서의 월별하수처리 유입량 및 방류량을 산정하였다. 최종적으로 회귀율(하수처리 방류량/실 공급량)을 산정한 결과 연평균 회귀율은 각각 93.97 %(2011년), 95.02%(2012년)로 과잉 추정 되었으며 7 ~ 9월의 회귀율은 110 ~ 120 %로 유입량을 초과하였다. 이는, 하수처리로 유입되는 유입량의 하수관거는 합류식으로 구축되어 7 ~ 9월에 많은 양의 강우량이 우수관을 통해 하수처리장으로 이송되어 생활용수 이외에 자연적인 공급량으로 인한 것으로 분석되었다. 따라서, 월별 회귀율 산정을 위해서는 불투수층에서의 면적강우량(mm)을 유입량(m3/s)으로 환산된 값을 고려하여 회귀율을 재산정하였다. 그 결과 연평균 회귀율은 각각 78.27 %(2011년), 77.58 %(2012년)로 나타났다.각각의 월별 회귀율도 매우 유사하게 나타났으며 과거 관용적으로 사용된 65 % 회귀율보다 약 12 ~ 13%로 증가하였으며 이는, 하수처리시설 구축 및 처리효율의 증가와 상수처리시설의 관로시설의 개량으로 인한 유수율 및 누수율 감소로 회귀율이 증가한 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.323-323
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• 2016

최근 강우강도 등의 기후변화로 인한 표토침식량이 증가하고 있고, 이에 따른 사회적 환경적 문제가 부각되고 있다. 특히 표토는 인류에게 식량생산의 기반이 되고, 정주공간을 제공할 뿐만 아니라 에너지 생산, 수자원 함양, 기후변화 대응, 생물 다양성 유지, 생태계의 건전성, 자원함양 및 순환, 오염물질 정화 등 소중한 생명자원이다. 이에 환경부에서는 2012월 12월 표토의 침식현황에 관한 고시를 제정하고, 표토 유실 대책 방안을 수립하기 위한 노력을 기울이고 있다. 이에 자원으로서의 표토를 보전하기 위한 단기적 관점의 대책 수립을 위한 웹GIS 기반 단일 강우에 의한 표토침식량을 예측하는 시스템을 개발하였다. 본 연구는 크게 표토침식 예측 모듈 개발과 정확성 평가를 위한 시험포 단위 모니터링 그리고 모듈을 적용한 웹GIS 시스템 개발, 시범적용을 위한 강원도 홍천군 자운리 DB 구축으로 구분된다. 표토침식예측 모듈의 정확성을 검증하기 위하여 가로 4m ${\times}$ 세로 22m, 경사도 3%, 9% 시험포 2개를 조성, 2015년 5월 11일부터 2015년 11월 23일까지 강우량, 유출량, 표토침식량을 조사하였으며, 웹 GIS 시스템은 Open Source Software인 Geoserver, PostGIS, OpenLayers를 활용하여 개발하였다. 마지막으로 개발된 웹GIS 표토침식예측시스템의 시범적용을 위하여 강원도 홍천군 자운리의 농경지 경계, 경사도, 경사장, 작물특성 등에 대한 GIS DB를 구축하였다. 시험포 모니터링 결과 강우발생일수는 총 64일로 관측되었고, 이중 유출은 총 30회가 발생되었다. 이 결과를 활용하여 표토침식 예측 모듈을 검증한 결과 3 % 시험포의 유출량 NSE : 0.88, $R^2$ : 0.91, 표토침식량 NSE : 0.87, $R^2$ : 0.90, 9 % 시험포의 유출량 NSE : 0.76, $R^2$ : 0.82, 표토 침식량 NSE : 0.82, $R^2$ : 0.88로 나타났다. 웹GIS 표토침식 예측 시스템은 Layer 정보, 맵, GIS tool, 경작기 정보, 날씨 정보 등으로 구성되어 있으며, 기상청 Open API와 연동하여 당일의 강수량 예보 데이터와 표토침식량 산정 모듈을 이용하여 예측 표토 침식량 데이터를 제공한다. 하루가 지나면 기상청에서 실측한 강수량 데이터를 이용하여 표토 침식량 산정모듈이 자동적으로 수행된 뒤 실측 강우량에 대한 표토침식량 정보가 제공된다 본 연구에서 개발된 웹GIS기반 표토침식 예측 시스템은 시범 대상 유역인 강원도 홍천군 자운리 유역을 대상으로 구축되었으며, 지속적으로 대상유역을 확대할 계획이다.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1545-1557
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• 2021

Crops show sensitive spectral characteristics according to their species and growth conditions and although frequent observation is required especially in summer, it is difficult to utilize optical satellite images due to the rainy season. To solve this problem, Constrained Cloud-Maximum Normalized difference vegetation index Composite (CC-MNC) algorithm was developed to generate periodic composite images with minimal cloud effect. In thisstudy, using this method, monthly Sentinel-2A/B Normalized Difference Vegetation Index (NDVI) composite images were produced for paddies and high-latitude cabbage fields from 2019 to 2021. In August 2020, which received 200mm more precipitation than other periods, the effect of clouds, was also significant in MODIS NDVI 16-day composite product. Except for this period, the CC-MNC method was able to reduce the cloud ratio of 45.4% of the original daily image to 14.9%. In the case of rice paddy, there was no significant difference between Sentinel-2A/B and MODIS NDVI values. In addition, it was possible to monitor the rice growth cycle well even with a revisit cycle 5 days. In the case of high-latitude cabbage fields, Sentinel-2A/B showed the short growth cycle of cabbage well, but MODIS showed limitations in spatial resolution. In addition, the CC-MNC method showed that cloud pixels were used for compositing at the harvest time, suggesting that the View Zenith Angle (VZA) threshold needsto be adjusted according to the domestic region.