• Korean Journal of Materials Research
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• v.26 no.3
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• pp.154-159
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• 2016

A roll-bonding process was applied to fabricate an AA1050/AZ91/AA1050 laminate complex sheet. Two AA1050 and one AZ91 magnesium sheets of 2 mm thickness, 30 mm width and 200 mm length were stacked up after surface treatment that included degreasing and wire brushing; material was then reduced to a thickness of 3 mm by one-pass cold rolling. The laminate sheet bonded by the rolling was further reduced to 2 mm in thickness by conventional rolling. The rolling was performed at 623K without lubricant using a 2-high mill with a roll diameter of 210 mm. The rolling speed was 15.9 m/min. The AA1050/AZ91/AA1050 laminate complex sheet fabricated by roll bonding was then annealed at 373~573K for 0.5h. The microstructure of the complex sheets was revealed by electron back scatter diffraction (EBSD) measurement; the mechanical properties were investigated by tensile testing and hardness testing. The strength of the complex sheet was found to increase by 11 % and the tensile elongation decreased by 7%, compared to those values of the starting material. In addition, the hardness of the AZ91 Mg region was slightly higher than those of the AA1050 regions. Both AA1050 and AZ91 showed a typical deformation structure in which the grains were elongated in the rolling direction; however, the mis-orientation distribution of grain boundaries varied greatly between the two materials.

• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.485-489
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• 2003

The region of Kochang(Chollabuk-Do) located in the west-southern area of the Korea and passed by the West Coast Expressway has the yellow collar soil(Hwang-To) primarily containing clay. Hwang-To serves as a soil appropriate for growing the watermelon and yam, but as a subgrade material not strong for constructing the roads. Particularly, the subgrade material of this study site was not qualified for the standard of the subgrade material quality. The properties of the subgrade layer showed that the strength of the subgrade material was not strong enough to sustain the subgrade strength in constructing the roads since the passing ratio of the No. 200 sieve was about 25％ to 82％ and the ground water level was early equal to subgrade one. Thus, the objective of this study was to present the methods obtaining the proper subgrade strength of cutting area to construct the secure and solid expressways in the fragile area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.8
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• pp.1619-1625
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• 2017

Civil global navigation satellite system (GNSS) does not meet user performance requirements for specific PNT (Positioning, Navigation, and Time) applications. Therefore, various differential systems are used to augment GNSS for improving positioning accuracy and integrity. The MTSAT satellite augmentation system (MSAS) is the Japanese satellite based augmentation system. This paper is for analyzing the characteristics of Japanese MSAS in Korean peninsula. First of all, it was done for analyzing not only DGNSS navigation signal but also the navigation parameter through simulation and experimental tests. As a result of data analyses, the sufficient navigation satellites to determine 3-D position based on DGNSS are simultaneously available at MSAS monitering station and the southern region of Korean peninsula. It was verified that the carrier to noise signals are stable to maintain the reliable 3-D position and that the level of 2m (2drms) accuracy is very similar to the ordinary worldwide DGNSS as well.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.12 no.1
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• pp.21-29
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• 2005

Purpose: The purpose of this study was to identify the frequency with which nursing interventions according to domains and classes, and core nursing interventions of the Nursing Intervention Classification (NIC) were performed by nurses on orthopedic surgery nursing units. Method: For this purpose, the third edition of NIC was used. Of the 486 nursing interventions, 424 were selected at 75% consent by experts. Data were collected from June, 2003 to July, 2003 5 hospitals and 69 nurses(return rate : 95.8%) in Gwang-ju and Chonnam region. 5 point Likert scale describing frequency was used. Results: The most frequently performed domain was 'physiological : basic'($2.97{\pm}.60$), followed by 'health system'($2.65{\pm}.65$) and 'physiological : complex'($2.55{\pm}.46$). The most frequently performed class was 'activity and exercise management'($3.82{\pm}.89$), followed by 'immobility management'($3.64{\pm}.62$), 'skin/wound management'($3.41 {\pm}.60$), 'physical comfort promotion'($3.23{\pm}.68$) and 'thermoregulation'($3.01{\pm}.91$). The most frequently performed nursing intervention was 'medication administration' ($4.96{\pm}.21$), followed by 'medication administration : intravenous'($4.93{\pm}.31$), 'analgesic administration'($4.91{\pm}.51$), 'pain management'($4.87{\pm}.34$) and 'medication administration : intramuscular'($4.78{\pm}.68$). Conclusion: In conclusion, the third edition of NIC was found to be a general and comprehensive classification system for application on orthopedic surgery nursing units. These findings will help in building of a standardized language for orthopedic surgery nursing units and enhance the quality of nursing care.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.890-897
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• 2021

Since the enforcement of strict regulations on marine fuel oil sulfur content, demand for Low Sulfur Fuel Oil (LSFO) has been increasing. However, as LSFO properties vary greatly depending on the supply timing, region, and supplier, LSFOs can experience problems with sludge formation, blending compatibility, and stability once mixed into storage tanks. This study investigates using ultrasound cavitation effects to improve the quality of LSFOs in storage tanks. For marine gas oil (MGO), the results showed that the relative ratio of high molecular weight compounds to those of low molecular weight decreased after ultrasonic irradiation, due to cavitation-induced cracking of chemical bonds. For marine diesel oil (MDO) and blended oil, a small increase in the relative abundance of low weight molecular compounds was observed after treatment. However, no correlation between time and relative abundance was observed.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.1
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• pp.40-48
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• 2021

Through a series of bollard pull tests of a propeller in partially submerged condition, thrust, torque, and shaft excitation force of a conventional propeller model were measured using a six-component load cell. By variation of the Weber number and Reynolds number, a consistent towing tank model test condition was derived. The effects of propeller immersion depth on the ventilation behavior and change of force and moment acting onto the propeller shaft were investigated. The decrease in thrust owing to the inception of ventilation was confirmed, and a large degree of dispersion of the thrust and torque coefficients were also observed in the transition region where the blade tip was under the water surface. The shaft excitation force was derived from the force and moment onto the propeller shaft.

• Journal of Cadastre & Land InformatiX
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• v.49 no.1
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• pp.145-156
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• 2019

This study analyses land related problems and its features which stems from a concession established by the imperialist countries from the late Joseon Dynasty to the Japanese colonial period. In order to achieve the purpose of this study, literature review related to the installation of the treaty ports and a concession was conducted and a chronological analysis was applied. As a result of the study, the East China Sea and the Japan were opened by the Western powers in prior to the East Asia region, Korea was an open harbor port led by Japan, which had experience installing an open harbor. In this circumstance there was a system that allowed foreigners to freely reside and exercise exertion rights (exercise one's extraterritoriality), which was a disadvantage to Joseon. In addition, the Japanese-style land area unit "Pyeong" was used in Japan's highly influential prefecture, and later became the basis of the unit of land used in the 1910 land survey project.

• Journal of Navigation and Port Research
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• v.43 no.2
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• pp.122-133
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• 2019

The maritime industry has emerged as a new growth engine. The municipalities that own the port are trying to add value through the maritime industry. Overseas port cities are also creating maritime industrial clusters to generate profits and strengthen competitiveness. Therefore, it is very important to understand the comparative status of the domestic maritime industry by region. Based on this analysis, it is possible to establish maritime industrial clusters and strategies for integration. This study analyzed the structure of the maritime industry located in Jeollanamdo province, the southwestern part of Korea. Through the analysis of existing literature, the maritime industry was reclassified into 5 major categories, 21 subcategories, and 84 subcategories. Based on the reclassified maritime industry, the analysis of the Jeollanamdo province maritime industry was based on applying the location quotient and the shift-share analysis. As a result of analyzing the geographical location of Jeollanamdo province, other industries showed the highest value of 2.790, followed by fisheries (2.227), shipbuilding industry (1.164) and marine tourism industry (0.554). The growth effect of the maritime industry in Jeollanamdo province was 35,323 people, and net growth effect excluding national growth effect was 11,945 people. In particular, the net growth effect of the shipbuilding industry was the highest at 11,320, followed by shipping logistics (6,371) and marine tourism (1,529). On the other hand, there was no net growth effect in fisheries. The results of this study can be used as basic data for the construction of the maritime industrial cluster for Jellanamdo province in the future.

• Journal of the Korea Society of Computer and Information
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• v.26 no.1
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• pp.179-188
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• 2021

This study investigated the purchase status, wearing status, purchase satisfaction, selection criteria, and improvement marin leports wear for subjects who enjoy marine leisure sports in the southwestern region of Jeollanam-do, and examines the correlation between age and body type and the correlation between variables. SPSS Ver. 26.0 program was used for analysis. In the correlation between the motivation for participation and the selection criteria, when participating to increase physical strength, it was selected based on the fit. When participating for leisure or hobbies, they were selected based on design and color. The relationship between the selection criteria and purchase satisfaction was not satisfied in terms of price when they were selected based on activity or utilization of other uses. As for the selection criteria according to the body type, clothing was selected based on price and fashion for large triangles and squares, and elasticity for inverted triangles. As for the preferred color by age, only those in their 40s preferred blue and other age groups preferred achromatic color. In future studies, it is thought that a study on the preference of each marine leisure sports item should be conducted.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1339-1348
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• 2021

There are variety of reasons for renewable energy curtailment, including lack of transmission availability and grid system stability. In the Jeju island region, there are many cases in which the supply of electricity is already increased compared to the demand for electricity due to the increase of solar and wind power generation facilities, and accordingly, the number of curtailments for wind power generation is increasing. This research aims to find the direction of efficient reception of renewable energy and stable operation of the power system using HVDC(High Voltage Direct Current) and BESS(Battery Energy Storage System) facilities that are in charge of power supply in Jeju island. And the paper suggests a practical operation plan for optimal system operation, and the direction of system operation of the land power system due to the expansion of solar and wind power generation facilities in the future.