• Environmental and Resource Economics Review
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• v.23 no.4
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• pp.553-581
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• 2014

This paper analyzes competition among service stations in the Korean gasoline market. We consider spatial differentiation as a source of product differentiation as well as the characteristics of the stations and vertical contracts between refiners and retailers as factors causing changes in equilibrium prices in the Korean gasoline retail market. The effect of the government's price disclosure policy on the retail market competition is also analyzed. Moran's I test indicates that the prices of neighboring gas stations are spatially correlated in the market. It is also found that gasoline prices for vertically integrated stations are much lower than those for independent stations. In addition, unbranded stations charge lower prices than branded stations but also induce branded stations to price more competitively. Meanwhile, the government's price disclosure policy did intensify price competition in the retail gasoline market. It is inferred that the price disclosure policy contributed to retailers gaining more bargain power in price negotiation with refiners, causing an eventual increase in retail prices.

• Journal of the Korean Institute of Rural Architecture
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• v.14 no.4
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• pp.67-76
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• 2012

The main purpose of this study is to understand the existing and the architectural characteristics of the Secondary Stations of Catholic Church in Jeju. The method of this study is to research all the literature and to visit. The time of establishment of the Secondary Stations of Catholic Church in Jeju was mostly 1950's, and that time was the heyday of the Secondary Stations of Catholic Church that was built in Korean. Catholicism was spread throughout Jeju during this time, and in the process, the Secondary Stations of Catholic Church was built. The Secondary Stations of Catholic Church in Jeju are sited mostly in coastal villages, and especially Catholicism was actively spread throughout the west of Jeju and the a large number Secondary Stations of Catholic Church were built in the west of Jeju. The Secondary Stations of Catholic Church were built between the mid-1950's to the mid-1960's. The plan type is kept as plan shaped of straight shape. When made an enlargement of the interior space and altered, framework of the Secondary Stations of Catholic Church was generally maintained. The head of the side window and the front door have the same design characteristics. When the belfry is located, it is attached to an outer wall of the Secondary Stations of Catholic Church, or is located to the left or the right the front of the Secondary Stations of Catholic Church. The design of belfry found expression in various forms. The buttress are not located in the others but in Young-su Gong-So, and it has not the structural functions but the design functions.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.3
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• pp.255-263
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• 2014

This paper deals with a construction plan of hydrogen fueling stations on express highways using geographic information system. We analyzed the existing hydrogen fueling stations and production facilities to construct the hydrogen supply system to satisfy the hydrogen demands. Also, we suggested the necessary number and locations of hydrogen fueling stations on express highways for operating fuel cell vehicles. As a result, we need to construct at least 6 hydrogen stations on express highways in 2020 and 14 hydrogen stations in 2025. In 2030, when fuel cell vehicles are expected to spread over the whole nation, 114 hydrogen stations are needed to construct on express highways. This study mainly utilized the information of distances between hydrogen production facilities and fueling stations. However, we need to analyze the other factors such as traffic and income data. Also, it is necessary to make a suitable construction plan of hydrogen fueling stations that should be constructed on each district using geographic information system.

• Industrial Engineering and Management Systems
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• v.4 no.2
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• pp.117-122
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• 2005

An assembly system (AS), a valuable tool for mass production, is generally composed of a number of workstations and a transport system. While the workstations perform some preplanned operations, the transport system moves the assemblies by special designed pallets from one station to another. One common problem associated with automatic assembly systems is that some assembly operations may have relatively long cycle times. As a consequence, the productivity, as determined by the operations with the longest cycle time, can be reduced significantly. Therefore, special forms of parallel workstations were developed to improve the performance of an assembly system. In this paper, three most commonly used parallel stations: on-line, off-line and tunnel-gated stations in a free transfer assembly system are studied via discrete event simulation. Our findings revealed that the off-line parallel system has the best performance because the two independent parallel stations can lower the buffer requirement; reduce the sensitivity to variability of processing time and balance of a line. On-line parallel systems were found to have a relatively poor performance, because the operations of two parallel stations block each other, and higher buffer capacity is required to achieve similar capacity. The tunnel-gated system was more efficient than the on-line system since the first parallel station can operate independently. More importantly, we have quantified the productivity of the three different strategies mentioned. Engineers can choose the optimal strategies for installing parallel stations under their working environment.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.4
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• pp.217-224
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• 2022

Due to the issue of the sustainability in transportation area, the number of electric vehicles has significantly increased. Most automakers have decided or planned to manufacture the electric vehicles rather than carbon fueled vehicles. However, there are still some problems to figure out for the electric vehicles such as long charging time, driving ranges, supply of charging stations. Since the speed of growing the number of electric vehicles is faster than that of the number of charging stations, there are lack of supplies of charging stations for electric vehicles and imbalances of the location of the charging stations. Thus, the location problem of charging stations is one of important issues for the electric vehicles. Studies have conducted to find the optimal locations for the charging stations. Most studies have formulated the problem with deterministic or hierarchical models. In this paper, we have investigated the fluctuations of locations and the capacity of charging stations. We proposed a mathematical model for the location problem of charging stations with the vehicle routing problem. Numerical examples provide the strategy for the location routing problems of the electric vehicles.

• Journal of Environmental Impact Assessment
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• v.21 no.5
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• pp.767-779
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• 2012

In case of executing surveys in marine ecosystems, the most important things are scientific selection measures of survey stations that can represent various ecosystems characteristics in subjected areas. The situations show a lot of differences that understand characteristics of marine ecosystems in targeted areas according to selection methods and positions in survey stations. Investigation ranges and station numbers in marine ecosystems are classified according to project characteristics and scales. But, currently a clear divisions or objective standards are not. Therefore, this study tried to provide selection measures of survey station in scientific and objective marine ecosystems through precise analysis among environmental impact statements of coastal development projects until now. In this study, impact scopes of marine ecosystems correspond to physical impact predictions by undertaking projects. Impact ranges were divided into three(physical impact ranges) coastal waters. In case of proposing numbers of survey stations according to this survey ranges, numbers of investigation stations due to minimum survey scopes in targeted projects applied 20~30% of all numbers in survey stations. Number of survey stations due to average investigation scopes within physical impact ranges applied 60~70% of all numbers in investigation stations. Numbers of survey stations due to maximum survey ranges within physical impact scopes applied 10~20% of all numbers in survey stations. So, improvement measures were deducted. Finally, according to prediction ranges in impact of various coastal development projects, several kinds of conclusions are suggested. And, it is thought to be able to use as fundamental database to select investigation stations in marine organisms through this study.

• Journal of Korean Society for Atmospheric Environment
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• v.3 no.1
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• pp.47-54
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• 1987

A new method for designing air pollution monitoring newtork is presented in this study. In this method, the magnitudes and the correlation coefficients of predicted concentrations in each grid points are examined and the monitoring stations are assigned to those stations which cover the damage cost the most. This method was applied to the Ulsan-Onsan Industrial Complex. This method turned out to be much more efficient than the method of TM coordinates and the method of concentric circles prescribed in the Standard Methods for Pollution Measurement as well as the existing monitoring system established in the area. The 21 stations selected by the method of TM coordinates could cover only 64.4% of the damage cost in the area, the 16 stations by the method of concentric circles 72.1%, and the existing 21 stations 67.8%, while 11 stations were enough to cover 90% of the damage cost in the area with this method. It also was found that this method required only 24 stations to cover the entire area.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1385-1395
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• 2008

The introduction of KTX(Korea Train Express) has brought an historic change to the overall transit system in Korea. Especially, the high-speed railway stations are expanding the scope as public transit centers. However, we cannot deny that the evaluation on the high-speed railway stations had not been performed successfully so far. The evaluation covers from the connectivity of the scope from door to the stations and the transfer service in the interior of stations. We developed the service evaluation indicators of transfer facilities in the high-speed railway stations. The indicators consist of level of service(LOS), the propriety of allocation, and the quality of information throughout the facilities in the centers. We examined the 7 stations in Korea and standardized the methodology of the evaluation process by applying the indicators. Also, the evaluation is performed easy for anyone to follow.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.49-55
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• 2006

The purpose of the present study is to analyse characteristics of the background noise for the broadband seismic stations in KMA. It is well known that the background noise arises continuously from long period microseism, sea waves, minute changes of atmospheric pressure, seasonal temperature change of the ground surface, culture activities, and etc. The background noise shows spatial and temporal changes and it has various characteristics such as its spectral amplitudes in frequency domain are not constant Such the background noise gives considerable influences on the quality of seismic record. To investigate annual variations, the background noise was separated into high frequency components of above 1Hz More larger average amplitude is found in winter than other seasons. The average amplitude for 12 seismic stations are compared. It is known that the background noise is considerably larger in stations located in island region such as Jeju, Ulleungdo, and Bagryeongdo seismic stations. However the noise is relatively small in inland stations such as Chuncheon, Chungju and Uljin seismic stations.

• Journal of Positioning, Navigation, and Timing
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• v.8 no.3
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• pp.129-138
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• 2019

In this work, we propose detection method for ionosphere storm that occurs locally using widespread GNSS reference stations. For ionosphere storm detection, we compare ionosphere condition with other reference stations and estimate direction of movement based on ionosphere time variation. The method use carrier phase measurement of dual frequency, for accuracy and precision of test statistics, are evaluated with multiple GNSS reference stations data.