• Journal of the Economic Geographical Society of Korea
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• v.15 no.1
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• pp.95-115
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• 2012

The initial market of alternative-fuel vehicle (AFV) will show geographically uneven distribution due to AFV's high price, and thus efficient location model should consider spatial variation of demand. This paper estimates AFV trips by incorporating an AFV demand estimation model with origin-destination (OD) trips. The estimates are the input for the flow-refueling location model that maximizes the OD flows that can be refueled by the given number of stations considering AFV's limited range per refueling. A scenario analysis is conducted by varying assumptions in estimating demands and AFV acceptance rate. Optimal location alternatives for Orland metropolitan area are provided and results are compared.

• Journal of the Korea Society of Computer and Information
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• v.22 no.10
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• pp.63-71
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• 2017

In this paper, we develop the system for audio volume equalization of video on demand(VoD) content and propose the solution for it. In recent years, there has been a steady increase in the number of VoD users in addition to linear channels. However, viewers ought to sit in an uncomfortable way, adjusting the volume intermittently while they are broadcasted. Sudden changes of volume occur between the broadcasting channels, the programs from the co-channel, or the linear channels and the VoDs. Especially, upsurged dissatisfaction from the televiewers has been found due to the unequalized volume when shifting between the linear channel and the VoD. In order to solve this problem, multilateral efforts were put forth, such as a system for keeping the volume at a certain level in digital broadcasting program has been legislated domestically. It leads success in equalizing linear channel volume. On contrary, too little notice has been taken for distorted volume problem of video on demand(VoD) content. In this paper, we developed and applied the volume equalization system into VoD content to achieve uniformization, a similar condition with linear channel(-24LKFS). This suggestion helped uneven current of volume which was in the stage -16 ~ -20LKFS to stable condition by lowering into the stage of -24LKFS. It also brought 20% increase in perspective of volume quality satisfaction level.

• Journal of Distribution Science
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• v.20 no.10
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• pp.1-9
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• 2022

Purpose: This study examines the economic and technical reasons for the uneven distribution of broadband internet services in Indonesia before and during the recession due to the C19 pandemic, and examines its effect on the country's economy. Research design, data and methodology: The research was designed by conducting an economic feasibility, which was verified through area observations and interviews with providers and their association, as well as the Regulator. Results: The results show that during the C19 pandemic, there has been an increase in the distribution of broadband internet services in Indonesia since there has been an increase in demand for cellular services and fixed services together. However, the increase in broadband internet service coverage is still not evenly distributed in the country and unable to boost the decline in Gross Domestic Product during the C19 pandemic. Conclusions: The increase in fixed broadband coverage by seventy percent is an indication for the state to make policies to encourage bundling techniques between operators with the aim of internet services being more evenly distributed throughout the country. Where, the influence of a more even distribution of broadband internet services in all countries is believed to be able to support the country's economy.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.8
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• pp.334-340
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• 2006

Copper is widely used in electric wire, cable, conductor in electric devices. As the demand for electric power is increasing rapidly, electric power devices are getting amazingly bigger and complicated. The using of light-weight conductor can reduce the size and making cost of the electric devices. In high-frequency application, Electric current in a conductor tends to shift to the surface of the conductor, resulting in an uneven current distribution in the inner conductor. In the extreme case the current may essentially concentrate in the 'skin' of the inner conductor as a surface current. In high frequency application, therefore, inner area of copper conductor may replace with aluminum conductor, which reduces the weight of conductor. This paper describes the manufacture and evaluation of composite conductors made of copper and aluminum. The optimum extruding ratio was 16 at $300^{\circ}C$. The electrical resistance of manufactured composite bus bar was $57{\mu}{\Omega}$ at DC and $49.5{\mu}\{Omega}$ at 300Hz.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.633-635
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• 2007

To cope with increasing power demand in metropolitan area, the power system in Korea has equipped with unit generator of large capacity, high density and uneven distribution, and transmission line of long distance, large capacity and high voltage. As the power system growing up enormous, it has become difficult to maintain the standard voltage in case of radical fluctuation of load or severe change of voltage by power system fault for its weakness of responsive characteristics although the power condenser has been installed to solve the unstability by lack of reactive power. Consequently, we review harmonic wave production and control characteristics to solve unstability problem of voltage in northern metropolitan, to reduce transmission restriction cost and to minimize load shedding by relocation of SVC (Static Var Compensator), which is highly effective for improvement of responsive characteristics for radical voltage fluctuation.

• Journal of Soil and Groundwater Environment
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• v.20 no.2
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• pp.1-9
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• 2015

Groundwater has been a very precious resource for human life and economic development in the world. With increasing population and food demand, the groundwater use especially for agriculture is largely elevated worldwide. The very much large groundwater use results in depletion of major aquifers, land subsidences in many large cities, anthropogenic groundwater contamination, seawater intrusion in coastal areas and accompanying severe conflicts for water security. Furthermore, with the advent of changing climate, securing freshwater supply including groundwater becomes a pressing and critical issue for sustainable societal development in every country because prediction of precipitation is more difficult, its uneven distribution is aggravating, weather extremes are more frequent, and rising sea level is also threatening the freshwater resource. Under these difficulties, can groundwater be sustaining its role as essential element for human and society in the near future? We have to focus our efforts and wisdom on answering the question. Korean government should increase its investment in securing groundwater resources for changing climate.

• Journal of the Korean Geographical Society
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• v.42 no.2 s.119
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• pp.177-195
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• 2007

The central aim of this paper is to identify the distributional pattern of poverty and to investigate the spatial relationship between poverty and welfare service providers in Busan, Korea. It is intended to explain how the relationship of service-dependency between impoverished people and social welfare services leads to uneven social geography. Welfare services controlled by public or private agencies may support the impoverished people in different ways, generating social outcomes. By exploiting the spatial variations in the incidence of poverty and the provisions of social welfare services, this paper is to understand the dynamics of the geography of poverty from a local scale so that it can help us understand how various governmental and nongovernmental area-based service providers are spatially uneven when they are compared to the distribution of service dependency group such as impoverished people. From this research, it is finally argued that the implications of locational interdependence between such needed groups and social welfare services for their support demand a paradigm for urban social geography that centers on the changing welfare provision structure and the linkages between population and service-provision.

• Journal of the Economic Geographical Society of Korea
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• v.5 no.1
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• pp.69-87
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• 2002

This study examines the spatial diffusion and locational charateristics of convenience stores in Daegu which had increased rapidly in the 1990s. The first convenience store (CVS) was introduced in the zone of transition of (Namgu district) adjacent to the city center or CBD in 1992. Thereafter they diffused into CBD and residential areas, but they have centered around places where their steady purchasing population was distributed. As a result, the spatial distribution of CVSs in Daegu shows a very uneven pattern concentrated in areas with many high school, in commercial and business areas, and apartment residential areas. It seems that this pattern is derived from two basic locational factors. Primarily, the location of CVSs in Daegu is very closely related with the spatial distribution of the demand population which will be clients for CVSs. Secondarily, it is also affected by the accessibility of streets which the demand population utilizes easily.

• Earthquakes and Structures
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• v.25 no.6
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• pp.417-427
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• 2023

If the center of mass and center of stiffness or strength of a structure plan do not coincide, the structure is considered asymmetric. During an earthquake, in addition to lateral vibration, the structure experiences torsional vibration as well. Lateraltorsional coupling in asymmetric structures in the plan will increase lateral displacement at the ends of the structure plan and, as a result, uneven deformation demand in seismically resistant frames. The demand for displacement in resistant frames depends on the magnitude of transitional displacement to rotational displacement in the plan and the correlation between these two. With regard to the inability to eliminate the asymmetrical condition due to various reasons, such as architectural issues, this study has attempted to use supplemental viscous dampers to decrease the correlation between lateral and torsional acceleration or displacement in the plan. This results in an almost even demand for lateral deformation and acceleration of seismic resistant frames. On this basis, using the concept of Torsional Balance, adequate distribution of viscous dampers for the decrease of this correlation was determined by transferring the "Empirical Center of Balance" (ECB) to the geometrical center of the structure plan and thus obtaining an equal mean square value of displacement and acceleration of the plan edges. This study analyzed stiff and flexible torsional structures with one-way and two-way mass asymmetry in the Opensees software. By implementing the Particle Swarm Optimization (PSO) algorithm, the optimum formation of dampers for controlling lateral displacement and acceleration is determined. The results indicate that with the appropriate distribution of viscous dampers, not only does the lateral displacement and acceleration of structure edges decrease but the lateral displacement or acceleration of the structure edges also become equal. It is also observed that the optimized center of viscous dampers for control of displacement and acceleration of structure depends on the amount of mass eccentricity, the ratio of uncoupled torsional-to-lateral frequency, and the amount of supplemental damping ratio. Accordingly, distributions of viscous dampers in the structure plan are presented to control the structure's torsion based on the parameters mentioned.

• Journal of The Korean Society of Agricultural Engineers
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• v.66 no.3
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• pp.25-37
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• 2024

Global warming-induced drought inflicts significant socio-economic and environmental damage. In Korea, the persistent drought in the southern region since 2022 has severely affected water supplies, agriculture, forests, and ecosystems due to uneven precipitation distribution. To effectively prepare for and mitigate such impacts, it is imperative to develop proactive measures supported by early monitoring systems. In this study, we analyzed the spatiotemporal changes of multiple evapotranspiration-based drought indices, focusing on the flash drought event in the southern region in 2022. The indices included the Evaporative Demand Drought Index (EDDI), Standardized Precipitation Evapotranspiration Index (SPEI) considering precipitation and temperature, and the Evaporative Stress Index (ESI) based on satellite images. The Standardized Precipitation Index (SPI) and SPEI indices utilized temperature and precipitation data from meteorological observation stations, while the ESI index was based on satellite image data provided by the MODIS sensor on the Terra satellite. Additionally, we utilized the Evaporative Demand Drought Index (EDDI) provided by the North Oceanic and Atmospheric Administration (NOAA) as a supplementary index to ESI, enabling us to perform more effective drought monitoring. We compared the degree and extent of drought in the southern region through four drought indices, and analyzed the causes and effects of drought from various perspectives. Findings indicate that the ESI is more sensitive in detecting the timing and scope of drought, aligning closely with observed drought trends.