• Journal of Navigation and Port Research
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• v.26 no.4
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• pp.383-390
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• 2002

The time cost of ship end cargoes is one of the most important data for decision-making of port investment and operational efficiency. Studies in this area were initiated internationally by Goss and Mann in late 70's and also done in Korea 10 years ago using the same methodology as Goss. The main purpose of this paper is to revisit to estimate the time cost using updated data. The estimation was undertaken sampling data on various investment and operating costs by vessel from 205 vessels, comprising 47.5％ of the notional fleet in Korea as well as on cargoes from international trade statistics. Compared with the study of 10 years ago, major finding of this research is that time costs of liquid and dry bulk carriers have increased, in case of the former type, showing almost doubled cost increase. The increase is deemed to be caused by very expensive LNG carriers. Lowered social discount rate in this study compared with 10 years ago, in general, has mused the costs to stay at similar level to the previous study. Sensitivity tests were conducted using various social discount rates.

• The Journal of the Convergence on Culture Technology
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• v.5 no.1
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• pp.361-369
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• 2019

With the commercialization of the ADAS functions, the need for the experience of the autonomous driving system is increasing, and the role of the artificial intelligence agent is attracting attention. This study is an autonomous driving experience experiment that verifies the effect of self-efficacy and agent embodiment. Through a simulator experiment, we measured the effect of existence of self-efficacy and agent embodiment on social presence, perceived risk, and perceived ease of use. Results show that self-efficacy had a positive effect on social presence and perceived risk, and agent embodiment negatively affected perceived ease of use. Based on the results of the study, we proposed guidelines for agent design that can increase the acceptance of the semi-autonomous driving system.

• 한국정보교육학회:학술대회논문집
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• 2021.08a
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• pp.419-424
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• 2021

The purpose of this study is to understand the educational context including the actual learning process and learner perception using the embodied metaphor in AI education. To this end, a class was designed to utilize the embodied metaphor-based unplugged activity through a qualitative approach. Matrix analysis technique was used to analyze the data collected throughout the course of the class to analyze the experiences and perceptions according to the characteristics of the learner, and the learning context. The results of the study were: First, there was a difference according to the learner's prior experience in the effect on the representative knowledge and the subsequent practice process. Next, the embodied metaphor-based unplugged activity showed soft landing effects on practice and text coding. Finally, the organic integration of unplugged and plugged-in classes helped learners understand the potential of computational thinking.

• Analytical Science and Technology
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• v.26 no.1
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• pp.19-26
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• 2013

Gibberllic acid ($GA_3$) is one of gibberellins (GAs) that are a class of plant growth hormones that exert profound and diverse effects on plant growth and development. $GA_3$ is essentially non-UV absorbing and is difficult to assay by UV-detector. For effective extraction of gibberellic acid from fruits by using liquid-liquid extraction, optimized pH and extraction solvent were established. The selective and sensitive derivative of $GA_3$ for HPLC/UV-vis was derivatized using phenacyl bromide, and the experimental factors, including reaction time, reaction temperature and amount of derivatizing reagent and base were investigated for the effective synthesis. The derivatized $GA_3$ with phenacyl bromide was effectively analyzed by HPLC/UV-vis. The structure of derivatized $GA_3$ was confirmed by HPLC/ESI-MS. For apple, LOD and LOQ were 0.008 mg/kg and 0.027 mg/kg, respectively. For pear, LOD and LOQ were 0.003 mg/kg, 0.012 mg/kg, respectively. The established method can be applied to more effective analysis of $GA_3$ from plant and food.

• 월간낙농육우
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• v.18 no.5 s.193
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• pp.71-75
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• 1998

• Korea Logistics Conference
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• v.10 no.2
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• pp.303-328
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• 2002

• 종축개량
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• v.9 no.4
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• pp.1-4
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• 1987

• 한국게임학회지
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• v.9 no.1
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• pp.29-33
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• 2012

• 월간낙농육우
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• s.65
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• pp.32-39
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• 1987

• 월간낙농육우
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• v.17 no.2 s.178
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• pp.109-113
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• 1997