• TTA Journal
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• s.51
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• pp.73-78
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• 1997

• TTA Journal
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• s.44
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• pp.34-43
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• 1996

• TTA Journal
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• s.50
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• pp.88-94
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• 1997

• Journal of Educational Research in Mathematics
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• v.26 no.2
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• pp.269-285
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• 2016

PCK(pedagogical content knowledge) has been frequently discussed in the field of subject matter education as well as education in general. Considering the fact that PCK characterizes teacher professionalism, and the distinction of mathematics education from neighboring disciplines, PCK is one of the core concepts in the discourse of mathematics education. This study focused on KCS(knowledge of content and students) among the areas of PCK. The purpose of this study to investigate the KCS of pre-service teachers attending a private university located in Seoul. An in-depth interview with 30 pre-service teachers was conducted in a semi-structured manner, using four questions dealing with common student errors, students' understanding of content, and student developmental sequences. The pre-service teachers gave mathematical answers while in others they gave priority to pedagogical considerations. The implication drawn from the interview data is that the teacher training program should fully reflect the complexity of mathematical concepts which appeared in school mathematics over several grade levels and content areas.

• Journal of Advanced Navigation Technology
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• v.24 no.1
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• pp.28-36
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• 2020

Korea augmentation satellite system (KASS) is the Korean satellite based augmentation system (SBAS) developed by ministry of land, infrastructure, and transport (MOLIT) since 2014. Since KASS is the safety critical system that can affect to the safety of airplane, the software of KASS is developed according to the DO178B software level induced from safety analysis. In case of KASS control station (KCS), most of the software of KCS get assigned software level E in DO178B. In that case, ECSS-Q-ST-80C category D is assigned as a software product assurance standard. In this paper, the software related standard ECSS-E-ST-40C, ECSS-Q-HB-80-04A are analyzed to satisfy ECSS-Q-ST-80C and as a result the software product assurance activities regarding software life cycle and the software quality model, metric is proposed for the product assurance of the KCS software.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.1
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• pp.1-8
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• 2022

To understand physical phenomena of ship maneuvering deeply, a numerical study based on computational fluid dynamics is required. A computational method that can simulate the interaction between the ship hull, propeller, and rudder will provide informative local flows during ship maneuvering tests. The analysis of local flows can be applied to improve a physical model of ship maneuvering that has been widely used in maneuvering simulations. In this study, the numerical program named as WAVIS that has been developed for ship resistance and propulsion problems is extended to simulate ship maneuvering by free-running tests. The six degree-of-freedom of ship motion is implemented based on Euler angles and the overset technique is applied to treat the moving grid of ship hull and rudder. The propulsion force due to a propeller is calculated by a panel method that is based on the lifting-surface theory. The newly extended code is applied to simulate turning and zig-zag tests of KCS and the comparison with the available experimental data has been made.

• Journal of Veterinary Science
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• v.24 no.2
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• pp.32.1-32.10
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• 2023

Background: The association between vitamin D and canine keratoconjunctivitis sicca (KCS) has not been investigated in dogs. Objectives: To investigate the association of serum 25-hydroxyvitamin D [25(OH)D] concentrations with Schirmer tear test 1 (STT-1) and tear film breakup time (TFBUT) in dogs. Methods: Sixty-one clinically healthy, client-owned dogs were enrolled. STT-1 and TFBUT were measured in 122 (61dogs) and 82 (41 dogs out of total 61 dogs) eyes, respectively. Serum 25(OH)D concentrations were evaluated by quantitative chemiluminescent immunoassay. The dogs were classified into 6 groups according to the evaluations (STT-1: group 1, normal [≥ 15 mm/min] in both eyes; group 2, normal in one eye and abnormal [< 15 mm/min] in the fellow eye; group 3, abnormal in both eyes; TFBUT: group 4, normal [≥ 20 sec] in both eyes; group 5, normal in one eye and abnormal [< 20 sec] in the fellow eye; group 6, abnormal in both eyes). Results: STT-1 was positively correlated with TFBUT (p < 0.001). Among the STT-1 groups, the mean serum 25(OH)D concentration in group 1 was significantly higher than in groups 2 and 3 with positive correlation (p < 0.001). However, there were no significant differences among the TFBUT groups 4, 5, and 6. Conclusions: In dogs, it was found that serum 25(OH)D concentrations had a greater effect on quantitative KCS than qualitative KCS. Therefore, it is considered that measurement of serum 25(OH)D concentration could be included in the diagnostic tests in canine quantitative KCS patients.

• Journal of Navigation and Port Research
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• v.37 no.1
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• pp.63-69
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• 2013

Since most merchant vessels are mainly influenced by the added resistance in an actual sea, they could be navigated more efficiently if this added resistance could be precisely predicted and then effectively reduced. In this paper, we have computed the effective horsepower based on the resistance performance in still water and then calculated the added resistance in regular wave in order to estimate a ship's propulsion performance on a voyage. Firstly, we have performed experiments using a model of KCS in a circulating water channel to estimate the flow characteristics around a container ship and the ship's resistance in still water. Then we have calculated the motion response function in regular wave as well as the values for the increase in resistance, and evaluated the ship's motion performance in waves according to the calculated response function. It was found that the resistance in waves increased because the ship's motion response value became larger as the ship's speed increased in the case of head sea. The effect of the added resistance could be reduced by maneuvering the ship to the encounter angle of $120^{\circ}$ in areas of long wavelengths and to head sea in areas of short wavelengths.

• 한국디지털정책학회:학술대회논문집
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• 2006.06a
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• pp.45-53
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• 2006

Ever since the computer came into being in early 20th century, rapid development of the information technology has led to the opening of the ubiquitous age where daily works can be done anywhere, anytime, and with any devices. The information technology has drawn attention from Customs around the world as a key means to fulfill multi-faced responsibilities of strengthening regional cooperation in the international trade, simplifying clearance procedures, expediting logistics flow, and ensuring security in the global supply chain. Korea Customs Service, which began the informatization effort by establishing the electronic export declaration system in 1992, completed the 100% electronic clearance system in 2000, with a number of countries now conducting benchmarking studies on the successful use of IT by KCS. This paper is to address the changes brought to the Customs administration in the information age, the progress and achievement of the Customs informatization as a proactive strategy to deal with the changing environment, and the exportation to overseas administration of the e-clearance system of KCS which strives to become the global leader of Customs informatization. The exportation. in particular, will not only lead to increased foreign currency earnings and shared know how, but also create an opportunity to reflect Korea's system in the standardization of Customs procedures around the world.

• Journal of Advanced Research in Ocean Engineering
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• v.2 no.2
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• pp.48-60
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• 2016

Accurate simulation of free-surface wave flows around a ship is very important for better hull-form design. In this paper, a computational fluid dynamics (CFD) code which is based on the open source libraries, OpenFOAM, was developed to predict the wave patterns around a ship. Additional anti-diffusion source term for minimizing a numerical diffusion, which was caused by convection differencing scheme, was considered in the volume-fraction transport equation. The influence of the anti-diffusion source term was tested by applying it to free-surface wave flow around the Wigley and KCS model ships. In results, the wave patterns and hull wave profiles of the Wigley and KCS model ships for various anti-diffusion coefficients showed quite close patterns. While, the band width of the water volume-fraction values between 0.1 to 0.9 at the Wigley and KCS model hull surfaces was narrowed by considering the anti-diffusion term. From the results, anti-diffusion source term decreased free-surface smearing.