• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.183-191
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• 2021

Non-intrusive load monitoring is a technology that can be used for predicting and classifying the type of appliances through real-time monitoring of user power consumption, and it has recently got interested as a means of energy-saving. In this paper, we propose a system for classifying appliances from user consumption data by combining GAF(Gramian angular field) technique that can be used for converting one-dimensional data to the two-dimensional matrix with convolutional neural networks. We use REDD(residential energy disaggregation dataset) that is the public appliances power data and confirm the classification accuracy of the GASF(Gramian angular summation field) and GADF(Gramian angular difference field). Simulation results show that both models showed 94% accuracy on appliances with binary-state(on/off) and that GASF showed 93.5% accuracy that is 3% higher than GADF on appliances with multi-state. In later studies, we plan to increase the dataset and optimize the model to improve accuracy and speed.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.5
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• pp.9-16
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• 2019

In today's global energy market, the importance of green energy is emerging. Hydrogen energy is the future clean energy source and one of the pollution-free energy sources. In particular, the fuel cell method using hydrogen enhances the flexibility of renewable energy and enables energy storage and conversion for a long time. Therefore, it is considered to be a solution that can solve environmental problems caused by the use of fossil resources and energy problems caused by exhaustion of resources simultaneously. The purpose of this study is to efficiently produce hydrogen using plasma, and to study the optimization of DME reforming by checking the reforming reaction and yield according to temperature. The research method uses a 2.45 GHz electromagnetic plasma torch to produce hydrogen by reforming DME(Di Methyl Ether), a clean fuel. Gasification analysis was performed under low temperature conditions ($T3=1100^{\circ}C$), low temperature peroxygen conditions ($T3=1100^{\circ}C$), and high temperature conditions ($T3=1376^{\circ}C$). The low temperature gasification analysis showed that methane is generated due to unstable reforming reaction near $1100^{\circ}C$. The low temperature peroxygen gasification analysis showed less hydrogen but more carbon dioxide than the low temperature gasification analysis. Gasification analysis at high temperature indicated that methane was generated from about $1150^{\circ}C$, but it was not generated above $1200^{\circ}C$. In conclusion, the higher the temperature during the reforming reaction, the higher the proportion of hydrogen, but the higher the proportion of CO. However, it was confirmed that the problem of heat loss and reforming occurred due to the structural problem of the gasifier. In future developments, there is a need to reduce incomplete combustion by improving gasifiers to obtain high yields of hydrogen and to reduce the generation of gases such as carbon monoxide and methane. The optimization plan to produce hydrogen by steam plasma reforming of DME proposed in this study is expected to make a meaningful contribution to producing eco-friendly and renewable energy in the future.

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.2
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• pp.24-31
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• 2008

Studies for demarcation of urban areas by ecological type have been developed, but the demarcation of urban areas by ecological perception is thus far dependent on artificial land use. Therefore, the purpose of this study is to find factors that account for the urban area ecosystems by surveying a variety of ecosystem factors. By land use type, the urban area of Gangdong District, Seoul was defined. Then ecological factors in each polygon were surveyed. Ecological factors are associated with energy use(building coverage ratio, floor area ratio and ground temperature), water circulation(biotope area factors and impermeable pave ratio) and biological diversity(bird appearance index and green area ratio). The correlation between each factor was analyzed. The results indicate that urban ground temperature is divided into three groups(high, middle and low) by the biotope area factor. The bird population is divided into two groups(abundant and scarce) by the green area ratio. Therefore, demarcating the urban areas by ecological type is applicable to the biotope area factor and green area ratio.

• Journal of Climate Change Research
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• v.4 no.2
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• pp.159-175
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• 2013

Emission reduction targets to respond to climate change have been discussed and set locally, nationally and globally. After Korean government set the national target in 2009, 16 metropolitan cities established voluntary emission reduction targets by 2020. This study review and compare historical greenhouse gas emissions, reduction target by 2020 and strategies in 16 metropolitan cities. Most cities chose a consumption-based inventory approach. Some cities set the reduction target excluding land use change and forestry (LUCF) at 30% against business-as-usual by 2020, while others set the absolute reduction target against past year including LUCF. The stringency of reduction target in metropolitan cities was evaluated differently according to the comparative indicators such as the targets against BAU or past year and per capita emission, etc. Key mitigation sectors were different across metropolitan cities. It is suggested that national government share detailed raw data for metropolitan cities' emission inventory with the local government. Using advanced mitigation model and two types' target based on BAU and historical year and integrating local government's climate change plan with its energy plan are also required.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.51.4-52
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• 2015

From 2010 to 2014, CQUEAN (Camera for QUasars in EArly uNiverse) has been operated for the observation at the 82 inch Otto Struve Telescope of the McDonald Observatory, US. This camera is optimized at wavelength range of 0.7 - 1.1 um with seven (g', r', I', z', Y, Iz and Is) broad-band filters for the survey of high redshift (z > 5) quasars in the early universe. We are upgrading this system to identify more details of SED (Spectral Energy Distribution) of quasar candidates and other astronomical sources. The SQUEAN is comprised of a focal reducer, a CCD camera, a new filter wheel, new auto guiding system and new control software. The new filter wheel consists of interchangeable cartridges for various wavelength and size of filters. 50 nm medium bandwidth filters from 600 - 1050 nm, seven SDSS (Sloan Digital Sky Survey) filters and Johnson-Cousin BVRI filters are installed for now. We also have a plan to use narrow band interference filters to classify high redshift quasars or to obtain SEDs of interesting astronomical sources in details more efficiently. We also developed KAP82 (Kyung Hee University Auto guiding Package for 82 inch telescope) for auto guiding software. CQUEAN and SQUEAN have been developed by CEOU (Center for the Exploration of the Origin of the Universe).

• Journal of Environmental Impact Assessment
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• v.17 no.5
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• pp.271-278
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• 2008

The purpose of this research provides the basic solution about waterfront and promotes the inherent capability, that recoveries both the river and gives the river for water quality to improve plan. In this study, we compare and analysis the slope contact between filter media of the porous concrete and planting concrete. As a result, when appling the porous concrete, it can show the removal efficiency is SS 53%, BOD 39%, COD 20%, T-N 36% T-P 42% and appling planting concrete is SS 58%, BOD42%, COD 26%, T-N 45%, T-P 53%. Therefore, planting concrete is higher removal efficiency (SS 5%, BOD 3%, COD 6%, T-N 9%, T-P 10%) than porous concrete. The experimental results show that using purification filter media on planting concrete is better than on porous concrete, because it have the higher purification filter efficiency. The quality of water improves vegetarian concrete, that can expect the increase of the self-purification capacity and improve the spectacle for providing the waterside and planting of planting concrete. In addition, it can complete and apply the research if having enough time for experimentation and accurate study for mechanism by plant, we can use both planting concrete filter media and the existing dike. As a result, we can gain the better quality of the water of the city's rivers and good economic value, that is spread by all cities applicable technologies. So it can be expected using well for future.

• KIEAE Journal
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• v.11 no.4
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• pp.87-94
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• 2011

This study was suggested to develop sustainable durability design system and proposed the plan to evaluate design conditions that meet the intended service life and $LCCO_{2}$ reduction level of reinforced concrete structure easily from the early design stage. For that the W/B and covering depth of the concrete structure were calculated through calculation of service life based on standard specification expression and the quantitative reduction rate of the vertical member of reinforced concrete structure by the calculated W/B was applied. Life cycle of building classified into construction stage, operation stage, maintenance stage, and demolition/disposal stage and the method of $CO_{2}$ evaluation of each stage was proposed. For construction stage, the major construction materials that take up over 80% $CO_{2}$ emitting during building construction were selected and the $CO_{2}$ evaluation method for 5 standard apartment houses was proposed. Also, for operation stage, $CO_{2}$ emission was calculated through calculation of heating load by energy efficiency rating certification system. For maintenance stage, $CO_{2}$ emission was calculated using concept of re-construction by life and for demolition/disposal stage was calculated with the use of construction standard estimate. As a result of the case study by such evaluation methods, 80 years of service life and 17 specifications of sustainable durability design that meet the 40% intended $LCCO_{2}$ reduction level were deduced. The Maximum $LCCO_{2}$ reduction rate was analyzed by 47.2%.

• Korean Journal of Human Ecology
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• v.20 no.1
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• pp.243-255
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• 2011

The purpose of this study was to learn the lifestyles of college students based on the green building certification system. The importance for environmentally friendly housing patterns will be changed and predicted to provide the basis for future residential development. The subjects of this research were 706 college students living in Jeonbuk province. The results of this research were as follows. College students' lifestyles were measured by self-confidence, family orientation, leisure orientation, economic orientation, and a digital directivity by factor analysis. In eco-friendly residential ratings, as the results of analysis according to the land use, the transportation, the energy resources, the environment load, the ecosystems, the interior environment, and the soundproofing of the interior environment came out to be higher than other factors. While coming out to be higher in the lower group in a digital directivity, the life style of the college students mostly came to be higher in the average of importance for environment-friendly housing. This result means that the college students want environment-friendly housing while attaching importance to the convenience of daily life, especially a digital directivity of housing. Thus, when we plan residences in the future, we will have to reflect the environment-friendly housing on the basis of the results of this research, and improve the environment which is contributing to help form college students' characters well.

• Journal of the Korean School Mathematics Society
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• v.12 no.4
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• pp.433-452
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• 2009

This study investigated the teaching strategies of two exemplary American teachers regarding word problems and their impact on students' ability to both understanding and solving word problems. The teachers commonly explained the background details of the background of the word problems. The explanation motivated the students' mathematical problem solving, helped students understand the word problems clearly, and helped students use various solving strategies. Emphasizing communication, the teachers also provided comfortable atmosphere for students to discuss mathematical ideas with another. The teachers' continuous questions became the energy for students to plan various problem solving strategies and reflect the solutions. Also, this research suggested a complementary model for Polya's problem solving strategies.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.371-379
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• 2010

Since Kyoto Protocol to the United Nations Framework Convention on Climate Change in 2005 takes effect, the transportation policies of most countries move toward encouraging the use of the transit mode with energy efficient and low carbon. Korea is 8th country of producing Co2 emissions and will be one of obligation countries decreasing Co2 after year 2013. In order to improve the efficiency of national transport system investment, this study developed the strategies toward rail-oriented transport system by considering operational speed and accessability, rail-oriented development, and introduce of ubiquitous technique in railway. The four major strategies targeted for future year are introduced here such as One-hour rail(connecting major cities within one hour), Seamless 30(accessing major railway stations within 30 minutes, Rail urbanism (railway-based urban planning), and U-rail (railway service with ubiquitous technique). Each strategy includes several action plans and their priorities are investigated using AHP(Analytic Hierarchy Process) to organize them by time scheme as short, mid, and long term perspective.