• The Korean Journal of Community Living Science
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• v.18 no.3
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• pp.493-505
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• 2007

The purpose of this study is to examine the regional differences of 0-12 aged children's environment based on their parents' socioeconomic class and on the character of the settlement. One thousand and two hundred households were investigated and the results are as follows. It is revealed that families in low socio-economic class are more likely to be exposed to noise and home crowdedness. Families living in spontaneous settlement are deprived of natural light and the roads to their homes are steep and narrow. Low income families face a housing affordability crisis. Most of them pay housing rent on monthly basis. The basic infrastructure of low income neighborhood is lacking convenient facilities like shopping centers, public transportation systems, banks, public parks, and libraries. This lack of facilities is more severe in spontaneous settlement. Instead, bars and taverns are located in their neighborhood. Accessibility to parks and resource centers is an important factor that makes both middle and low income families consider their neighborhood to be positive and this condition is counted better in social housing area than in spontaneous settlement. On the contrary, social networks like friends and relatives are strong in spontaneous settlement and families in poverty value these relationships. Such networks are weak in social housing area and this difference is not related to their residential period. Low income families living in social housing area are more pessimistic about their future and this view might result from their counterpart middle class neighbors and the weak social networks.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.49-59
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• 2004

In order to be a hub-port in Northeast Asia, current China government has intensively invested in port development. Further, this development Project is significantly big scale, compared with those projects which Korea and Japan have. Thus, China is beginning to threaten Korean ports, especially Busan port which try to be a hub port in Northeast Asia. For this reason, recently many studies to evaluate competitiveness between Korean ports, especially Busan and Gwangyang, and Chinese ports have been conducted. In the mean time, implications of those pervious research has mainly been based on evaluation of port competitiveness using evaluation methodologies, such as AHP(Analytical Hierarchy Process) and HFP(Hierarchical Fuzzy Process). However, as previous evaluation algorithms are methodologies that only calculate ranking of ports by competitiveness level, from the results of analysis, critical weak points affected current port competitiveness could not clearly fine out. That is, because there has not been any algorithm that can extract critical points from the evaluation results. The aim of this paper is to present critical points that affect port competitiveness using an algorithm based on IRFE(Inverse Relation of Fuzzy Evaluation), and scenario analysis, from previous results of evaluation of port competitiveness. And The research scope is to covey the subjective ports of Korea and China's 7 major ports (Busan, Gwangyang, Sanghai, Qingdao, Tienjin, Dalian and Kaoshuing). From analysis, it was found that critical weak point of Busan port is the level of hinterland including availability of free trade zone.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.597-603
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• 2012

The cases for selecting contact materials of Ag and AgC for Bias Track Relay are the studies and their safety evaluations are proposed in this paper. The welding at the relative low current has occurred in Ag contacts, but the one has not occurred in AgC contacts although the high currents flow since it has an excellent temperature characteristic. In the repetitive switching experiment, more unstable resistance and transfer phenomena has occurred in contacts as the switching numbers of AgC contacts increase, which results in more consumption of contacts. In the experiments, there exists a trade off relationship between welding and resistance variation. AgC contacts have excellent characteristics in welding, but the caution is required in using them since a lot of repetition switching produces much resistance variation. However, Ag contacts have excellent characteristics in repetitive switching, but weak ones in welding.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.783-788
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• 2021

Although the Korean government (Ministry of Ocean and Fisheries) and related organizations are enforcing many policies to improve the marine safety of vessels with weak safety management, the effectiveness of each policy is deficient due to the lack of a risk assessment method for ship safety management. Most previous studies in Korea of the risk assessment of ships only dealt with fragmentary risks of individual marine accident risks, so a new assessment method for comprehensive marine accident risk is needed. Examples of comprehensive risk assessments for ship safety management are the selection method for inspection targets by the Port State Control and the Norwegian Maritime Authority. In this study, indicators for the comprehensive risk assessment of ship safety management were developed for and applied to coastal/offshore fishing vessels that occupy a high proportion of the registrations and marine accidents in Korea. As a result, the risk of each ship was confirmed quantitatively, and a ranking of the weakness factors for ship safety management was identified.

• Journal of Environmental Science International
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• v.27 no.10
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• pp.845-851
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• 2018

In this study, the runoff characteristics of the non-rainfall period were examined using daily rainfall data from 1977 to 2017 and the data of runoff into the dam. Results showed that, the mean runoff decreases with longer non-rainfall periods in the Andong dam basin. The correlation coefficient between non-rainfall days and average runoff reaches 0.85. The results of the analysis of the runoff characteristics during the non-rainfall period, based on the preceding rainfall of Andong dam are as follows. The runoff characteristics of the entire non-rainfall period, shows that, for a rainfall of 1.0 mm or less, the runoff height was larger than the rainfall size and the base runoff larger. The correlation between the antecedent rainfall and runoff height was reached as high as 0.9864 in the 30 ~ 50 mm interval of the antecedent rainfall period, and this is the interval where the linearity of rainfall and runoff was at its maximum in the Andong dam basin. The correlation between the antecedent rainfall and the runoff height reached 0.92 for rainfalls of 100.0 mm. However, for rainfalls of 100.0 mm greater, the correlation between the antecedent rainfall and runoff height during the rainfall period was 0.64, which is relatively small. In this study, we investigated the runoff characteristics of the rainfall period in the Andong dam watershed. As a result, it was confirmed that the mean runoff decreased with rainfall duration. The linearity was found to be weak for rainfall events greater than 100.0 mm. The results of this study can be used as data for water balance analysis and for formulating a water supply plan to establish water resource management of Andong dam.

• Journal of Korean Society of Transportation
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• v.22 no.5
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• pp.47-57
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• 2004

This study introduces the areawide road safety improvement program, which was developed to overcome the weak points of conventional black spot improvement programs. The latter has been criticized in terms of that it can cause the problem of accident migration and that it prevents from identifying causes of road accident in the comprehensive scope. On the other hand, the areawide road safety improvement program can allow us to find the route or areas that have quite a number of road accidents with the common causes. Therefore, we can take countermeasures effectively in a different framework in this approach. This study explains in detail about the concept, procedures, and effects of areawide road safety improvement programs including the example. This study may contribute to bringing a new framework of road safety improvement program in Korea.

• Journal of Korean Society of Transportation
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• v.27 no.5
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• pp.75-82
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• 2009

Air transport markets are composed of airlines' networks through their base airports. The analysis of an air transport market has been focusing on determining the efficiency or competitiveness of airports or airlines in the market using number of routes, number of passengers, transfer rates, revenues, costs, and other data. However, little work has been done in analyzing the airport network itself. Assuming the air transport markets of Korea, China, and Japan are integrated, this paper aims to analyze the characteristics of the resulting airport network. To that end, the degree of connectivity, the degree of closeness, and the betweenness of centrality are employed. The analysis shows that Incheon International Airport is better than most other airports in terms of the degree of connectivity and that of closeness. Airports in Japan, however, exhibit strong connectivity but weak closeness and betweenness of centrality. Although it has low connectivity, Shenyang Airport has a possibility of becoming an attractive point of the integrated market in the future due to its high degree of closeness.

• Journal of Ceramic Processing Research
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• v.20 no.2
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• pp.158-163
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• 2019

Er3+/Yb3+-codoped NaLa(MoO4)2 colloidal nanocrystals were synthesized by pulsed laser ablations in de-ionized water and sodium dodecyl sulfate (NaC12H25SO4, SDS) aqueous solution for up-conversion (UC) luminescence bio-labeling applications. The influences of the SDS molecules on the crystallinities, crystal morphologies, crystallite sizes, and UC luminescence properties of the prepared Er3+/Yb3+-codoped NaLa(MoO4)2 colloidal nanocrystals were investigated in detail. Under a 980-nm excitation, the Er3+/Yb3+-codoped nanocolloidal NaLa(MoO4)2 suspension exhibited a weak red emission near 670 nm and strong green UC emissions at 530 and 550 nm, corresponding to the intra 4f transitions of Er3+ (4F9/2, 2H11/2, 4S3/2) → Er3+ (4I15/2). When the SDS solution was used, a smaller average crystallite size, narrower size distribution, and enhanced UC luminescence were observed. These characteristics were attributed to the amphoteric SDS molecules attached to the positively charged Er3+/Yb3+-codoped NaLa(MoO4)2 colloidal nanocrystals, effectively occupying the oxygen defect on their surfaces. The Er3+/Yb3+-codoped nanocrystalline NaLa(MoO4)2 suspension prepared in the SDS solution exhibited a remarkably strong green emission visible to the naked eyes.

• The Journal of the Petrological Society of Korea
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• v.24 no.3
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• pp.181-191
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• 2015

The Bakseok of Geunjeongjeon Hall in Gyeongbokgung Palace is platy floor stone acting as drainage, protected glaring and sliding. The Bakseoks were composed of anisotropic medium-grained biotite granite with a weak myrmekitic texture. Interpretation of transportation process for the Bakseok and original granite provenance trace of and analyze of identity based on ancient writings and detail field survey. As a result, the very similar granite with the Bakseok in lithology, composition mineral, texture and geochemical characteristics was found around Mt. Nakgasan in the Seokmodo Island. There were interpreted stonework process of the Bakseok used exfoliation granite dome with physical weathering properties in Seokmodo Island, to get platy stone economically stonework at the state level as a minimized on burden of supply and men power.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.4
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• pp.91-99
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• 2022

By applying METHOD 514.8 of the US military standard MIL-STD-810H, vibration analysis of the winding core automatic feeding device was performed during vehicle transportation. The contact point between the LM guide and main support frame was weak in the vertical axis, transverse axis, and longitudinal axis during the transportation of the automatic winding core feeder vehicle, and the maximum equivalent stress was 236.31 MPa in the longitudinal axis. When random vibration was applied, the safety margin in the longitudinal direction was 0.26, indicating low safety. The safety margin was changed by increasing the damage factor to 0.1. Finally, the safety margin was improved to 3.48 to secure safety. Resonance occurred with a Q factor of 9.34 in the harmonic response to which the RMS value of the ASD data was input, and the vertical axis safety margin was derived as 0.16. When the damping factor was 0.15, the Q factor was 3.37, and resonance was avoided with a safety margin of 6.62.