• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.3
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• pp.107-114
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• 2001

Electro-mechanical battery (EMB) consists of a high-speed fly wheel with an integral motor/ generator suspended on magnetic bearings and in an evacuated housing. Permanent magnet (PM) machines as the EMB motor/ generator are a popular choice, since there are no excitation losses which means substantial increase in the efficiency. In this paper we present the comparison of conventional slotted and slotless ring-wound types, aimed at EMB and other high-speed drives. We firstly discuss the topology of each machine for this particular application. these machines are primarily designed as 1kW two-pole PM generator with the rated speed of 40000 rpm. the motoring torque of 0.51 Nm has to be enough to accelerate the flywheel to the rated speed. We then present the comparison of the open-circuit field, the armature reaction field and winding inductance. next we analyze the induced voltage and the developed torque per unit stack length and unit weight of different machines. Finally, we estimate and compare the losses and the efficiency at motoring and generating modes.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.8 no.4
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• pp.17-23
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• 2012

Due to reinforcement of international environment regulation and high oil prices, interest in renewable energy is growing. Countries participating in UNFCCC are continuously putting efforts in reducing greenhouse gas after enforcing Kyoto Protocol into effect on Feb, 2005. Energy used in buildings, which relies heavily on fossil fuel accounts for about 24% of total energy consumption. In this study, air, geothermal and water source heat pump systems for an 322 $m^2$ auditorium in an office building is simulated using TRNSYS version 17 for comparing energy consumptions. The results show that energy consumptions of air, geothermal and water source heat pumps are 14,485, 10,249, and 10,405 kWh, respectively. Annual equal payments which consider both initial and running costs become 5,734,521, 6,403,257 and 5,596,058 Won. Thus, water source heat pump is the best economical choice.

• The Research Journal of the Costume Culture
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• v.27 no.1
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• pp.33-45
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• 2019

This study identified types of online retail internationalization in the fast-fashion context and proposed driving factors of retailers' choices in online-based market entry following the logic of the Uppsala model and the eclectic theory. In particular, this study proposes three types of online-based internationalization: 1) entering a host market with a physical store first, and then expanding with an online store, 2) entering a foreign market with an online store, then expanding to physical stores, and 3) entering only with an online business. In addition, this study investigated the causal factors, ownership-specific and location advantages, that influence the choice of the type of developmental process of online-based internationalization. To develop theoretical and managerial insights into the issue researched, this study employed a qualitative research design involving case studies of three European fast-fashion retailers, H&M, TOPSHOP, and ASOS. This study suggested that fast-fashion retailers that enter a host market with high ownership-specific advantages are likely to choose to enter the market with physical stores and then expand with online stores. On the other hand, when faced with uncertainties attributable to low ownership-specific or location advantages, fast-fashion retailers are likely to choose to enter with an online store first and then expand with physical stores as conditions change. Consequently, this study provides a better understanding for fast-fashion retailers who are willing to expand their businesses to foreign markets via online stores.

• International Journal of Human Ecology
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• v.8 no.1
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• pp.67-78
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• 2007

The aim of this paper was to compare differences and similarities of farmhouses between Denmark and Korea as a cross-cultural study. Farmhouses built during the 18th and 19th centuries in Denmark, and ones from Chosun Dynasty (AD. 1392-1910) in Korea were targets of this study. Literature study and field trips to districts and open-air museums in both countries were used. Field trips were carried out during summer of 2005 in Denmark, and fall of 2005 in Korea. Detailed comparisons focused on farmhouse plans, the use of rooms and furnishing, and building materials. As a conclusion, some differences were found between the two countries. In terms of farmhouse plans, square types with four wings, and parallel types were the most frequent forms in Denmark, while a few types, such as the "I", "L", "U" shapes and square types, were more frequently found in Korea. In Denmark, the most important room was the dwelling-room, in which daily family life took place. Every member of the family slept, ate, and worked here, and kept geese and young animals during the winter season. Therefore, this room was laid out in the center of the house. However, Anbang, the most important room in Korea, was not situated in the best part of the house. Instead, the Daechung-maru occupied the center and the best place because the daechung-maru, in which the ancestral ceremony was held, was thought of as more important than a place for live people. Also the use of rooms and furnishing was quite different between the two countries, reflecting each life style. Danish furnishings represented practical daily life, while Korean furnishings reflected more conceptual aspects. It might have resulted from Confucianism in the Chosun Dynasty, which ruled daily life and even influenced use of rooms and furnishings. In other word, philosophy influenced common peoples' daily life and living environment. With reference to building materials, there was rarely a difference between the two countries. Major materials for farmhouse were quite common, such as half-timbering wood and clay, but the difference was in bricks and roof coverings. Bricks were rarely used in Korean farmhouses, while rice-straw was rare for the roof of a Danish farmhouse. Of course, the choice of materials was strongly affected by the local surroundings and overall environment. This result can give some clues for design ideas when architects and interior designers plan housing that is adapted for local peoples. This kind of cross-cultural study can also contribute to one's understanding of foreign culture, especially in housing and culture. And, it can broaden one's insight of design ideas for designers who have to compete frequently with designers in foreign countries.

• Environmental and Resource Economics Review
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• v.25 no.2
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• pp.199-228
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• 2016

This study investigates the effects of economic factors and forest environments on rural residential area development in seven north central states of the U.S. by focusing on the relative importance of not only economic factors but also forest environments by forest type as core drivers of residential development. An empirical model of locations and magnitudes of population changes since 1950 in the north central region is first constructed, and then a panel model with fixed effects for counties is used to explain population growth by age group over time at the county level. Then a set of three equations is estimated for three major age groups, and a cross-sectional model is estimated for the last time period that regresses county-level environmental amenity variables on fixed effects coefficients for counties. Finally, an equation explaining changes in rural housing density is estimated. The results imply that immigrant age is a key factor influencing the choice of the place of residence and that the effects of environmental amenity factors on population growth and subsequent housing development in a county vary according to the age group.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.6
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• pp.50-59
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• 2015

This study aimed at suggesting Willingness To Pay (WTP) for introduction of the Traffic Accident emergency Call (TAC) system by using Contingent Valuation Method (CVM) which is a general valuation method. As the method, this study suggested a WTP estimation method of the TAC system with the double-bound dichotomous choice model. In previous studies, the data are processed differently according to the type of questions and analysis models used for the calculation of willingness to pay. Therefore, we re-organized the model by the cases using the truncated data sets, and showed the difference in WTPs. The dataset was developed by more than 500 questionnaire obtained from online and offline survey with the consideration of composition ratio by age group referring housing census in 2010 to mitigate regional bias of samples. At last, this study applied various statistical methods, survival analysis, multiple regression, and Tobit model for better interpretation of the questionnaires.

• Journal of Digital Convergence
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• v.17 no.6
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• pp.417-426
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• 2019

This researched is an investigation about the youths runaways street life experienced, the crimes committed through the influenced living in the street by looking into the effectiveness of the youth welfare and make an observation of their direction. The survey was conducted on young people who met in the youth shelter and outreach program, and finally analyzed 259 copies. The results of the study are as follows. First, When comparing the ages of the runaway youths if not properly given a support, services and prevention after running away from home, these youth will live their life in the street until their adolescents. Second, Runaway youth shelter has been providing the needs of those runaway youth who came in the shelter. However, it needs necessary new policy and services that will augment the support in solving problems of the youths when they visit youth shelter to ask for help and support. Third, It can be seen that the flight behavior after the street life is increased. They are in a situation where they have no choice but to join the juveniles for street life. Finally, Street life Youth self-reliance, support for living expenses, housing facilities, job opportunities, technical and job skill training were highly desired by the youths. Eventually, the intervention of youth living in street life requires a multifaceted support such as housing, labor, education, and welfare.

• Journal of Korean Society of Transportation
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• v.34 no.6
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• pp.510-522
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• 2016

In studies involving public transport, social welfare improvement is simply explained by the increase in public transport demand. However, the increase in the demand for public transport is mostly observed by the change in the frequency of public transport service, and in-vehicle crowding in public transport has not been an object of concern. This study examines and tries to reveal the cause of the changes of the social welfare and in-vehicle crowding of the changing public transport from imposing congestion pricing. We observe that congestion pricing increases in-vehicle crowding in public transport. This predictable phenomenon is more exacerbated in case of not operating bus-only lane. It should be noted that in-vehicle crowding is more increased in suburban, but in First-best toll system it tends to get worse less than it in other congestion pricing systems. We identify that the change of in-vehicle crowding is affected by the change of proximity of the housing to workplace, the number of commuting trips, and unpredictable distortion effect of the congestion charge.

• The Journal of the Korea Contents Association
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• v.18 no.10
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• pp.279-288
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• 2018

Unlike the past, the elderly who are growing rapidly in Korea are called 'active seniors'. They prefer to live in urban silver towns despite high living cost and make their own new urban contents. The new urban contents that reflect the living characteristics of active seniors have an important impact on their choice of residential location. Therefore, the purpose of this study is to identify the location characteristics of urban silver towns, which are preferred as the main residence of active seniors, based on the urban living contents of active seniors. The location characteristics of urban silver towns considering the urban living contents of active seniors can be classified 1) public transportation, 2) nearby arterial roads, 3) culture shopping facilities, 4) medical facilities, 5) apartment complexes, and 6) natural environments. Especially, the accessibilities of medical facilities, apartment complexes, and culture shopping facilities were the main characteristics of urban silver towns. The results of this study are expected to be helpful not only the location of urban silver towns, which is the urban new content of active senior, but also for the policy on housing for the elderly.

• Journal of the Korean Geographical Society
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• v.43 no.4
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• pp.511-525
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• 2008

Residential segregation is often considered to be one of the social problems that intensify urban inequality This study reviews three different frameworks about the causes of residential segregation and tests their validity in the real world. The review focuses on racial/ethnic residential segregation in U.S. cities since it has been blamed for persistent socio-economic gap among racial/ethnic groups. The three different segregation frameworks include 'spatial assimilation' that attributes segregation to low degree of assimilation and acculturation, 'place stratification' to discriminatory practices in the housing and mortgage markets such as steering, blockbusting, and redlining, and 'resurgent ethnicity' to racial/ethnic preference in residential choice, particularly in-group attraction. As an effort to test their validity, the paper examined residential pattern changes of the four major Asian nationality groups through 1990s and found that their residences got decentralized but re-cluster in some selected suburbs. This supports 'resurgent ethnicity' largely and 'spatial assimilation' only partly.