• Horticultural Science & Technology
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• v.19 no.1
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• pp.87-91
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• 2001

The aim of this study was to select the proper temperature for MA storage and to study the effect of sodium selenate ($Na_2SeO_4$) on storability of hydroponically grown sweet basil. Sweet basil was cultured with 1 fold using the nutrient solution developed by European Vegetable R & D Center in Belgium. Three-weeks before harvest, sodium selenate ($Na_2SeO_4$) was treated 2, 4, 6 and $8mg{\cdot}L^{-1}$ in the nutrient solution. Although electrolyte leakage of sweet basil was remarkably increased because of chilling injury at $5^{\circ}C$ MA storage, storage life was extended for three more days by selenium supplement. The weight loss was lower at $10^{\circ}C$ than at $5^{\circ}C$ and vitamin C content was higher at $10^{\circ}C$ than $5^{\circ}C$ storage treatment. Se treatment increased vitamin C content and decreased ion leakage in the plant. Accumulation of Se in the leaves of basil was increased with Se concentration of the nutrient solution. Se accumulation was $66{\mu}g{\cdot}g^{-1}$ dry mass at $2mg{\cdot}L^{-1}$ treatment and $422{\mu}g{\cdot}g^{-1}$ dry mass at $8mg{\cdot}L^{-1}$ treatment. The results suggest that storage at $10^{\circ}C$ is good for reduction of chilling injury and maintain marketability of basil. Less than $2mg{\cdot}L^{-1}$ sodium selenate treatment is acceptable for human health.

• Journal of Korea Port Economic Association
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• v.34 no.4
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• pp.69-84
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• 2018

The purpose of this study is to provide a comparative evaluation of container port criteria at four major container ports in the Bay of Bengal, including Colombo Port in Sri Lanka, Chennai Port in India, Chittagong Port in Bangladesh and Yangon Port in Myanmar. Important container port selection criteria are identified and comparisons among container ports are made using previous studies, personal interviews and questionnaires, completed by top shipping companies, freight forwarders, logistics service providers, and experts in Myanmar. The AHP method is used to verify the research model and hypothesis. This study identified five main criteria and eleven sub-criteria when choosing potential regional hub ports among the four ports in the Bay of Bengal. The main findings from the five main criteria suggest that port efficiency is the highest priority criteria, and the second priority is port costs. The criteria of geographical location and available port facilities are the third and fourth most important, respectively, and the last priority is port's hinterland. Regarding the relative competition among these ports, Colombo Port obtained the highest priority among the four influential factors except for port hinterland. This study has certain limitations that will require future research. First, the sample group for the population size is relatively small. Second, interviewees had limited experience answering questionnaires using this methodology and a limited amount of time was available for respondents for the interviews.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.69-81
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• 2021

Coastal shipping performs a pivotal role as a national transportation network and is highly valuable in terms of enabling more economical transportation at affordable prices than road transportation. In this regard, this study aimed to examine changes in the characteristics and centrality of South Korea's costal shipping sea-route networks by analyzing the centrality of domestic coastal shipping. To this end, social network analysis was used as an analysis technique that enables an analysis on the characteristics of coastal shipping networks. As a result, Jeollanam-do showed the highest degree centrality, ranking first in both the in-degree and the out-degree. Jeollanam-do also exhibited the highest betweenness centrality, and Gangwon-do registered the highest closeness centrality. In terms of hub and authority centrality, Jeollanam-do topped the list, followed by Gyeongsangnam-do and Gangwon-do in order. Lastly, Jeollanam-do ranked highest in the hub index, followed by Incheon, other regions, and Gangwon-do in order. This study is significant for suggesting the cities and provinces that play a key role in coastal shipping each year and their corresponding items. Future studies are recommended to identify the trend of coastal shipping through more detailed research on each port by city and province.

• Journal of the Korean Geographical Society
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• v.44 no.2
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• pp.187-205
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• 2009

Failures on network components of a public transportation system can give rise to the severe degradation of entire system functionality. This paper aims at exploring how potential failures can affect the system flows and reliability of subway network systems in Metropolitan Seoul. To evaluate the range of impacts of disruptions, this research employs a probabilistic approach, network reliability. Network reliability measures the network resiliency and probability of flow loss under a variety of simulated disruptions of critical network components, transfer stations in subway system. By identifying the best and worst scenarios associated with geographical impact, as well as evaluating the criticality of transfer stations, this research presents some insights for protecting current subways systems.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.85-93
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• 2015

This research try to find how to construct On & Off Marketplace to activate exporting of broadcasting contents by Delphi survey. This research is based on environment of broadcasting contents such as OTT and reinforcement for broadcasting contents marketplace of foreign countries. This research find that global marketplace of broadcasting contents should be constructed by convergence of online and offline, and should adopt new technology to make easy global distribution in new broadcasting environment, and also open global festival with offline marketplace of broadcasting contents. korea will be asia hub for global distribution of broadcasting contents through this task.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.7
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• pp.911-918
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• 1997

The turbulent viscous wake flows behind a single airfoil, two-dimensional stationary blade row and three-dimensional rotating blade row were calculated, and the numerical results were compared with experimental ones. The numerical technique was based on the SIMPLE algorithm using three turbulent closure models, standard k-.epsilon. model(WFM), low Reynolds number k-.epsilon. model(LRN) and Reynolds stress model (RSM). In the case of a single airfoil, WFM, LRN and RSM presented fairly good velocity distributions in the wake compared with experimental data. In the case of the stationary blade row, LRN and RSM presented better results than WFM for wake velocity distribution, and especially LRN showed best results among these three turbulent models. In the case of the rotating blade row, WFM and LRN showed fairly good agreement with experimental data of the three-dimensional velocity component distributions in the range from hub to mid span region. LRN was also superior to WFM in accuracy of prediction for the wake velocity distribution as same with the cases of a airfoil and the stationary blade row.

• Composites Research
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• v.18 no.4
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• pp.52-58
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• 2005

A cyclocopter propelled by the cycloidal blade system, which can be described as a horizontal rotary wing, is a new concept of VTOL vehicle. In this paper, optimized structure design is carried out for the aerodynamically optimized cyclocopter rotor system. Database is obtained fer design variables such as stacking sequence (ply angles), number of plies and spar locations through MSC/NASTRAN and optimum values are determined by RSM and some other optimizing processes. For the rotor system including optimized blade and composite hub m, the maximum stress by static analysis is within the failure criteria. And the rotor system is designed for the purpose of avoiding possible dynamic instabilities by inconsistency between frequencies of rotor rotation and some low natural frequencies of rotor.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.5
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• pp.104-110
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• 1998

In automotive industries, various processes for the cost reduction have been investigated lively. As one of them, powder metallurgy becomes influential. Compared to other methods used for he manufacture of steel components the Powder metallurgy process is competitive primarily due to the small number of production steps to reach the final geometry and thereby also the energy-efficiency. In this paper, to alter present forging process into powder metallurgy process by which the automotive clutch disc spline hub is manufactured machining process, the mechanical properties of sintered materials is investigated by specimen test. Selecting the 3 kinds of materials-SMF 4040, SMF 9060 and DHP-1, their properties according to heat treatment such as carburizing -tempering and plasma-nitrodizing are compared. By result of specimen test - tensile test, compression ring test, Impacting test, measurment of hardness, and microstructure analysis - we concluded that SMF 9060 and carburizing-tempering heat treatment is an optimal material and heat treatment method for the spline hub. It will be able to reduce manufacturing cost and weight.

• Fire Science and Engineering
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• v.16 no.2
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• pp.33-37
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• 2002

This study has investigated hydrodynamic of torque characteristics for disc of butterfly valve that is used in control for fire-protection water, The free-streamline theory is applied to predict hydrodynamic of torque characteristics. The torque characteristics of disc are corrected for the angles of attack of valve disc and surrounding velocity of flow by theoretical torque equation, and correction equation is added. The torque characteristics of disc are investigated for the ratio of hub thickness to the valve diameter. The result of prediction are shown to be successful as that show typical torque characteristics of butterfly valve. Since the velocity distribution around the disc is confirmed in a visualization, it is confirmed that the free-streamline theory can be used to predict the torque characteristics of disc.

• Journal of Korean Library and Information Science Society
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• v.48 no.3
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• pp.259-279
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• 2017

The academic library has the ideal environment as a facilitator of knowledge creation, as a space where researchers can collaborate and as a creation hub center on campus. Recently, based on the 4th Industrial Revolution and creative theories, the maker space is gradually being introduced into academic libraries in foreign countries. Maker Space of the academic library is the best place to discover new knowledge and interests, practice, and interdisciplinary education. In this study, we propose a plan to introduce the maker space of domestic university libraries through case studies of domestic and overseas university and university libraries.