• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.4
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• pp.90-104
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• 2023

This study analyzes the perceptions of college students majoring in aviation services according to the field learning program conducted during their major studies in order to reflect the educational value and academic awareness of the experience of the experiential field learning program. A survey is conducted targeting college students who experience a field learning program conducted by the Aviation Service Department of J University, a four-year university in the Chungcheong region. ANOVA (one-way analysis of variance) is conducted to analyze differences in perceptions of field learning properties, learning satisfaction, academic self-efficacy, and intention to continue studying. Additionally, text mining is conducted using 'Voyant Tools' to analyze students' field trip logs regarding field trip learning program activities. I hope that the results will be used as evidence to build an efficient and systematic learning strategy for operating field learning programs.

• Journal of the Korean Society for Heat Treatment
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• v.4 no.4
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• pp.44-52
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• 1991

The effect of deformation temperature and manganes contents on the tensile properties of duplex stainless steels with the structure of both ferrite and austenite were investigate. For this investigation, Fe-19% Cr-5% Ni-4~8% Mn alloys were prepared. The result obtained from this experiment are summerized as follows. With decreasing deformation temperature, tensile strengths of duplex stainless steel increased. Elongation showd to be increased and then decreased after representing the highest value at specific temperature. Tensile properties of duplex stainless steel were controlled by TRIP behavior in this experimental range of austenite contents. Tensile strengths decreased with increasing Mn contents. With increasing Mn contents, elongation decreased in the high temperature region, but increased in the low temperature region. The peak temperature representing the maximum elongation were changed to low temperature and the width of peak appeared to be broaden with increasing Mn contents.

• Journal of Korea Planning Association
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• v.54 no.1
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• pp.52-66
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• 2019

Travel is a factor that stimulates the vitality of the urban and is widely used as an indicator of sustainable growth of the region. In Korea, however, no studies has been made to predict changes in traffic and calculate the accessibility of the region by comprehensively considering the socio-economic conditions of the travelers. The purpose of this study is to classify commuters according to the household income and to analyse the traffic characteristics of each class. The analysis results are aggregated into two. First, the analysis of study found different transport characteristics for different income classes. This is the result that underpins the argument of a previous study that suggested that a discriminatory approach is necessary for each income in determining the accessibility of the region. Second, this study calculated utility values differently for each income class based on the transit time and cost required between each zone. Through these measures, transport characteristics were analyzed by income class using indicators that considered transportation infrastructure, and socio-economic conditions of the travelers. This study is meaningful in that it provided the basis for calculating the accessibility that could take into account the activities of the housing consumers in establishing domestic housing policies.

• Journal of Korean Society of Transportation
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• v.35 no.1
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• pp.1-10
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• 2017

The compact city usually provides good accessibility of residents with multiple transportation modes. However, in a compact city, annual average of travel distance per household by car is relatively short due to more congested traffic condition and larger travel cost than disperse city. As a result, total travel demand is decreasing when the region becomes more compact. Therefore compact development is regarded as one of the sustainable choices for future urban planning in many countries. This study aims at an empirical analysis of the relationship between urban compactness and travel demand based upon land-use and travel data for city of Seoul. In this study, 424 sub-districts with the mixed land-use patterns are assessed in a hexagonal diagram. The measurement is based on the relative deviation of each sector's characteristics including numbers of residence, manufacture, and trade & service. Multiple linear regression models are developed to analyze the effects of urban compactness on zonal trip generations. As a result, the trip generation rate in the residence-intensive and mixed-use areas is found to be relatively low. Furthermore, residents in high-compact areas tend to use public transport more often than residents in less compact areas.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.12
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• pp.529-535
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• 2006

In DC tracking power supply system, ground faults are currently detected by the potential relay, 64P. Though 64P relay detects ground fault, it cannot identify the faulted region which causes long traffic delays and safety problem to passengers. A new ground fault protective relay scheme, ${\Delta}I$ ground fault protective relay, that can identify the faulted region is presented in this paper. In ${\Delta}I$ ground fault protective relaying scheme, ground fault is detected by 59, overvoltage relay, which operates ground switch installed between the negative bus and the ground. It preliminarily chooses the faulted feeder after comparing the current increases among feeders and trips the corresponding feeder breaker. After some time delay, it then recloses the breaker if it finds the preselected feeder is not the actual faulted feeder. Whether or not the preselected feeder is the actual faulted feeder is determined by checking the breaker trip status in the neighboring substation in the direction of the tripped breaker. If the corresponding breaker in the neighboring substation is also tripped, it finally judges the preselected feeder is actually a faulted feeder. Otherwise it recloses the tripped breaker. Its algorithms is presented and verified by EMTP simulation.

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05a
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• pp.67-75
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• 2001

Anticipated water scarcity in the first half of this century is one of the most concerned international issues. However, even though the issue has an international impact and world wide monitoring is critical, there are limited number of global estimates at present. In this study, annual water availability was derived from annual runoff estimated by land surface models using Total Runoff Integrating Pathways (TRIP) with 0.5 degree by 0.5 degree longitude/latitude resolution globally. Global distribution of water withdrawal for each sector in the same horizontal spatial resolution was estimated based on country-base statistics of municipal water use, industrial water use, and agricultural intake, using global geographical information system with global distributions of population and irrigated crop land area. The total population under water stress estimated for 1995 corresponded very well with former estimates, however, the number is highly depend on how to assume the ratio how much water from outside of the region can be used for water resources within the region. It suggests the importance of regional studies evaluating the possibility of water intake as well as the validity of the investment for water resources withdrawal facilities.

• Ocean and Polar Research
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• v.43 no.4
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• pp.219-227
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• 2021

Sea surface height (SSH) anomalies were estimated from data recorded by four pressure-recording inverted echo sounders (PIESs) in the Mindanao Current region over a duration of 2 years from December 2017 to November 2019. The steric components of SSH anomalies were derived from round-trip acoustic travel times from the sea floor to the sea surface, whereas mass-loading components were derived from bottom pressures. Temporal variabilities in the total (steric and mass-loading) SSH anomalies and the steric component are extremely similar; this result implies that the steric component plays a major role in SSH anomalies in this region. Comparisons of the PIES-derived SSH anomalies with satellite-measured SSH anomalies reveal that the former has less temporal variability. Correlation coefficients between the total SSH anomalies and satellite-measured SSH anomalies are less than 0.85, which is lower than the correlation coefficient between the steric components and satellite-measured SSH anomalies.

• Journal of the Korean Geographical Society
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• v.48 no.4
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• pp.545-556
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• 2013

This study sets up nodal regions for shopping and leisure with 424 district units located in Seoul and examines the characteristics of the vertical structure and the regional system. According to the higher-order analysis result, the trip for leisure forms a greater part, and about each of the nodal regions of the first stratum, major spots for origin and destination are located in the center, and those spots are connected to adjacent district units located nearby. As the factor's eigenvalue is bigger, the spatial range gets greater, too, and is located in outsides. And in the third or higher strata, either linkage between Gangnam and Gangbuk or leapfrogging linkage according to the bipolar factors is distinctive. Linkage between nodal regions centering around Jongro-gu, Jung-gu, Gangnam-gu, or Yeoungdeungpo-gu is not distinct, and in particular, the nodal regions of Jongro Geumcheon are maintained as the upper strata being independent from other nodal regions from the second or higher strata.

• The Journal of Natural Sciences
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• v.11 no.1
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• pp.137-142
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• 1999

JC Raulston Arboretum of the North Carolina State University houses 113 species of Korean native landscape woody plants. Styrax japonicus 'Emerald Pagoda'[formerly 'Sohuksan'] is native to Korea, China, and Japan. 'Emerald pagoda' is a special cultivar found by DR. J.C. Raulston during the United States National Arboretum plant collection expedition of the island of Sohuksan at the Western end of the Korea in 1985. Incredible, thick, glossy, large-leafed form of this beautiful white flowering tree found in Korea in 1985. It was probably the most outstanding ornamental plant to come from the expedition after his trip to Sohuksan and Chindo in the harsh perilous islands of the coast of Korea. He brought this one back in his suitcase. Viburnum awabuki 'Chindo' is and evergreen broadleaf shrub. It is for screening and as fire resistant trees in the southern region of Korea, because of its compact, leathery leaves. 'Chindo' was discovered on the island of Chindo by the U.S. National arboretum plant exploration team including J.C. Raulston during its 1985 Korean trip. Cuttings were taken from this plant, and liners were produced over subsequent years. These liners are now being evaluated for hardiness and fruit production throughout the Southeast of USA.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.33-42
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• 2020

This study analyzed the bicycle traffic patterns and identified the influence factors for each traffic purpose using the household traffic conditions survey for Seoul. The results are summarized as follows. First, as a result of surveying the bicycle traffic ratios according to the administrative dongs, there was a difference of 14.2% by region. Second, various personal characteristic variables, such as age, gender, income, occupation, and housing type, affect the bicycle mode choice, and bicycle passage increases when using facilities in residential areas. Third, among the neighborhood environments, the bicycle traffic for commuting purposes appeared to increase more in the areas of higher land use mix and lower crime rates. In addition, the bicycle road density and the inclination of the area commonly affect bicycle travel for commuting, shopping, exercising, and leisure.