• Journal of Soil and Groundwater Environment
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• v.13 no.6
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• pp.103-107
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• 2008

In this work, soil environment policy which should be taken into account at brownfield redevelopment projects was deduced from investigation on their environmental impact assessment statements. Soil contamination sources such as small-scale factories were found at a few large-scale brownfield projects, so contaminated soils did often exist at these sites. Especially, military facilities within the sites caused severe soil contamination problems. Therefore, soil environment policy was presented in detail to solve soil contamination problem at brownfield redevelopment projects. Furthermore, land-use planning focusing on greening (soil and vegetation) should be pursued at brownfield redevelopment projects in order to maximize environmental benefits of greenspace.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.3
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• pp.56-63
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• 1999

In power system, substation facilities have become too complex and large according to extended power system. Also, some facilities becorre old and often break down unexpectedly. In order to improve the sectrity of transformer out of substation facilities, the development of diagnosis technique to transformer is very needed. In this paper, we developed a method to be analysis the origin and degree of aging by KSOM based on the dissolved gases in power transfonrer. KSOM can do topological mapping for the multi-dimensional pattern based on the dissolved gases to two dimensional plane. And potential possibility and degree of aging for nonna1 transfonrer are presented using the proposed quantitative criterion. Furtherrrore, the aging process of transfonrer is analyzed based on the proposed criterion to special transfonrer. To demonstrate the validity of peoposed method, case study is performed and its results are presented.sented.

• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.85-93
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• 1999

The destruction of hazardous chemicals such as chlorinated organic compounds(COCs) and nitroaromatic compounds(NACs) by zero-valent iron powder is one of the latest innovative technologies. In this paper. the rapid dechlorination of chlorinated compounds as well as transformation of nitro functional group to amine functional group in the nitroaromatic compounds using synthesized zero-valent iron powder with nanoscale were studied in anaerobic batch system. Nanoscale iron, characterized by high surface area to mass ratios(31.4$\textrm{m}^2$/g) and high reactivity, could quickly reacts with compounds such as TCE, chloroform, nitrobenzene, nitrotoluene, dinitrobenzene and dinitrotoluene, at concentration of 10mg/L in aqueous solution at room temperature and pressure. In this study, the TCE was dechlorinated to ethane and chloroform to methane and nitro groups in NACs were transformed to amino groups in less than 30min. These results indicated that this chemical method using nanoscale iron powder has the high potential for the remediation of soils and groundwater contaminated with hazardous toxic chemicals including chlorinated organic compounds and nitro aromatic compounds.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.513-518
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• 2015

Salinity gradient power (SGP) has attracted significant attention because of its high potential. In this study, we evaluate reverse electrodialysis (RED) with various compositions of available resources. The polarization curve (I-V characteristics) shows linear behavior, and therefore the power density curve has a parabolic shape. We measure the power density with varying compartment thicknesses and inlet flow rates. The gross power density increases with decreasing compartment thickness and increasing flow rate. The net power density, which is the gross power density minus the pumping power, has a maximum value at a compartment thickness of 0.2 mm and an inlet flow rate of 22.5 mL/min. The power density in RED is also evaluated with compositions of desalination brines, seawater, river water, wastewater, and brackish water. A maximum power density of $1.75W/m^2$ is obtained when brine discharged from forward osmosis (FO) and river water are used as the concentrated and the diluted solutions, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.5
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• pp.347-352
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• 2017

Reverse electrodialysis (RED), which generates electrical energy from the difference in concentration of two solutions, has been actively studied owing to its high potential and the increased interest in renewable energy resulting from the Paris Agreement on climate change. For RED commercialization, its power density needs to be maximized, and therefore various methods have been discussed. In this paper, the power density was measured using various flow shapes based on the aspect ratio, opening ratio, and number of distribution channels. We found that the power density is enhanced with a decrease in the aspect ratio and an increase in the opening ratio and number of distribution channels.

• Journal of the Korean Institute of Gas
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• v.26 no.5
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• pp.10-15
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• 2022

Currently, some urban gas companies are conducting their own gas AMI meter verification projects, along with the demonstration of gas AMI (Advanced Metering Infrastructure) meters under the supervision of the government. There are many positive factors such as remote meter reading and ensuring user gas safety through AMI meter installation, but on the other hand, there are also many problems such as battery discharge, expensive price, and decreased reliability of remote meter data. This study sought various improvements in gas AMI meters along with prevention of serious civil disasters by preemptively eliminating structural safety problems and potential risks from gas leakage due to the expansion of gas AMI meters, and it is expected that this study will contribute to the government's policy to advance gas AMI.

• Korean Journal of Ecology and Environment
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• v.50 no.3
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• pp.337-354
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• 2017

Cyanobacteria Aphanizomenon population is widely distributed in the world, and well known as harmful algae by producing toxins and off-flavor materials, thus belonging to one of the taxa that became more interested in the field of limnoecology. In this study, the frequency, intensity, and duration of Aphanizomenon occurrence were increased with the abnormal drawdown of water level in the winter in Boryeong Reservoir, and the spatial and temporal characteristics of them are compared with each other in the perspective of hydrometeorology (1998 to 2017) and limnology (2010 to 2017). In Korea, Aphanizomenon flourished mainly in high temperature, and the appearance in the low temperature was rare in total five times. The harmful cyanobacteria Aphanizomenon was observed in the low temperature (December to February) in Boryeong Reservoir from 2014, and then reached a maximum value of $2,160cells\;mL^{-1}$ in January 2017. In addition, the period exceeding $1,000cells\;mL^{-1}$ at this time was more than 3 months. This was simultaneously associated with abnormal water level fluctuation in the low temperature ($<10^{\circ}C$). The large drawdown of water level in the winter season has the potential to promote or amplify the germination and development of harmful algae. Also, subsequent water quality and ecological impacts(e.g., algal toxins and off-flavor substances) need to be considered carefully.

• Journal of Korea Technology Innovation Society
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• v.21 no.4
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• pp.1207-1236
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• 2018

This paper explores the life cycle of innovation cluster, especially focussing on the Korean representative innovation cluster, Daedeok Innopolis. For this purpose, we review theoretically how an innovation cluster has been growing up. In particular, we discuss how a cluster has been formed and activated by governmental innovation policies from an evolutionary perspective. By doing so, the study identifies the typical features of an innovation cluster according to each dimensions of the cluster life cycle. The results of this study are as follows: First, in this study, Daedeok Innopolis has characteristics of latency, emergence, growth, and maturity from evolutionary perspective. Second, the governmental structure of the Daedeok Innopolis is a strong government-led and top-down structure, which has features of inclusiveness and flexibility such as umbrella policy. Third, the Daedeok Innopolis can be seen that adaptive or renewal development, as while, it can be applied fine adjustment the innovation cluster policy towards the recognition of innovation obstacle at each dimensions of the life cycle. Therefore, these discussions expose what kind of policy interventions should be addressed to form and develop the innovation cluster according to the cluster life cycle, as while, the development of adaptive policies during the risk and take-off period. Ultimately, the study provides that a different kind of policy instruments and tools should be implemented according to innovation cluster development and its distinctive characteristic per each dimensions of the cluster life cycle.

• Journal of Intelligence and Information Systems
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• v.28 no.3
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• pp.119-137
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• 2022

Recent recommendation system studies apply various deep learning models to represent user and item interactions better. One of the noteworthy studies is ONCF(Outer product-based Neural Collaborative Filtering) which builds a two-dimensional interaction map via outer product and employs CNN (Convolutional Neural Networks) to learn high-order correlations from the map. However, ONCF has limitations in recommendation performance due to the problems with CNN and the absence of side information. ONCF using CNN has an inductive bias problem that causes poor performances for data with a distribution that does not appear in the training data. This paper proposes to employ a Vision Transformer (ViT) instead of the vanilla CNN used in ONCF. The reason is that ViT showed better results than state-of-the-art CNN in many image classification cases. In addition, we propose a new architecture to reflect side information that ONCF did not consider. Unlike previous studies that reflect side information in a neural network using simple input combination methods, this study uses an independent auxiliary classifier to reflect side information more effectively in the recommender system. ONCF used a single latent vector for user and item, but in this study, a channel is constructed using multiple vectors to enable the model to learn more diverse expressions and to obtain an ensemble effect. The experiments showed our deep learning model improved performance in recommendation compared to ONCF.

• Journal of Korean Home Economics Education Association
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• v.33 no.4
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• pp.31-48
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• 2021

The purpose of this study was to provide an understanding of the trajectories of multidimensional health among older adults, including depression, chronic diseases, and cognitive function. Data were drawn from the 1-6 waves of the Korean Longitudinal Study of Ageing(KLoSA), and a sample of 2,059 respondents aged 65 and older at baseline was used for the analyses. Latent growth curve models and growth mixture models were used to explore the changes in depression, chronic diseases, cognitive function, and heterogeneous trajectories among them. One-way ANOVAs with Scheffé post-hoc analysis and chi-square tests were used to find differences in sociodemographic characteristics, health behaviors, and life satisfaction across the latent trajectory classes. Latent growth curve models revealed that depressive symptoms and the number of chronic diseases increased over time, while cognitive function showed gradual decreases. Three heterogeneous patterns of multidimensional health trajectories were identified: normal aging, increase in chronic diseases, and chronic deterioration. Significant differences were observed in sociodemographic characteristics, health behaviors, and life satisfaction across the three latent classes. In particular, low educational attainment, household income, and life satisfaction were associated with the chronic deterioration class. Based on the findings, we discussed suggestions for health promotion education targeting older adults. This study also emphasizes the importance of home economics education in promoting health literacy across the life course.