• Journal of the Society of Naval Architects of Korea
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• v.46 no.6
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• pp.587-594
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• 2009

In the paper the effect of a stern-plate attached to a ship was taken into account. The relationship between the trim angle of a ship and the wave-resistance coefficient induced by the a stern-plate was studied using the potential flow analysis method. Numerical algorithm was described using the panel method and the vortex lattice method(VLM) to simulate the flow phenomena around a ship. The non-linearity of the free surface boundary conditions were considered using the iterative method and the IGE-GMRES(Incomplete Gaussian Elimination-The Generalized Minimal RESidual) algorithm was adopted to solve the linear equation at each iterative step. Numerical calculations were carried out to investigate the validity of the adopted algorithm using KCS(KRISO 3600 TEU Container) hull. Possible cases for attachment of the plate were checked. The results showed that the numerical algorithm could be physically appropriate.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.285-297
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• 2018

The purpose of this study is to examine the trends of import and export of Korea by each continent and to find ways to increase export to Korea in the future. Each continent selected Asia, Europe, North America, Central and South America, and the Middle East. The analysis period was 220 months from January 2000 to April 2018, and data were collected from the KCS. Regression analysis showed that the coefficient was higher in Asia, Europe, North America, Middle East and Latin America. The markets of each continent moved independently of each other and were statistically significant at t statistic and p-value(${\leq}0.01$). As a result of this study, Asia and North America have been major export markets in Korea. Europe, the Middle East and Central and South America are emerging as new markets in Korea. In order to increase Korea's exports in the future, there is a need for continued interest in Asian markets including China & Southeast Asia.

• Resources Recycling
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• v.28 no.3
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• pp.68-76
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• 2019

It is very necessary for the metal recycling industries and the researchers to understand the current status of demand and supply of non-ferrous metals and their scraps. Domestic demand and supply of non-ferrous metals and their scraps have been surveyed and reported on the journal of the Korean Institute of Resources Recycling since ten years before. However, it was confined to six major non-ferrous metals such as copper, aluminum, zinc, lead, nickel and magnesium because there are so many kind of non-ferrous metals. In this article also, demand and supply of these non-ferrous metals in addition tin during recent five years (2014 ~ 2018) in Korean markets were reviewed, and their recycling ratio of scraps were briefly estimated. The statistical data were mainly cited from the data issued by Korea Customs Service (KCS) and Korea Non-Ferrous Metal Association, and some fragmental published review articles from magazines and other technical reports.

• Communications of Mathematical Education
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• v.33 no.2
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• pp.85-104
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• 2019

The purpose of this study is to analyze the tasks developed through task development activities with emphasis on mathematical connectivity, and to provide implications for teacher education to enhance teacher's competence. For this purpose, I analyzed the task developed by 52 pre-teachers through the activities. As a result, they combined mathematics with 'other subjects', 'mathematics', 'phenomenon', 'technology' and 'real life'. And they also made various internal connections of 'Different representation', 'Part-whole relationship', 'Implication', 'Procedure', and 'Instruction-oriented connection'. From the point of view of teacher knowledge, the study revealed that CCK and SCK were positive in terms of 'logical' and 'expression', and KCT as 'strategic' was meaningful but disappointing in diversity; however in terms of 'level', the KCS was limited due to tasks that did not meet the level of students. As such, this analysis reveals that teachers continue to struggle with understanding students' level, but exhibit little difficulty with 'logic', 'expression' and 'strategy. This being the case, teacher education needs to place additional emphasis in understanding students' levels and planning corresponding activities.

• Journal of the Korean School Mathematics Society
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• v.23 no.4
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• pp.427-448
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• 2020

The purpose of this study is to confirm the MKT(Mathematical Knowledge for Teaching) of the pre-service mathematics teachers on the normal distribution through the comparative analysis between the sub-elements of the MKT. In addition, it is to examine the factors that cause the difference of the subjects' MKT. To accomplish this, by the subject of 24 secondary pre-service mathematics teachers, in this study the test items of the MKT on the normal distribution were developed and data were collected and analyzed. As a result of the analysis of the MKT test sheet, the CCK(Common Content Knowledge) of the preparatory mathematics teacher was confirmed as a high score, whereas the SCK(Specialized Content Knowledge) and KCS(Knowledge of Content and Students) were confirmed as low scores. In addition, through these results, it could be confirmed that the difference in MKT of preparatory mathematicians occurred.

• Herbal Formula Science
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• v.31 no.4
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• pp.253-264
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• 2023

Objectives : Bambusae Caulis in Liquamen (BCL), a traditional herbal medicine, is a distilled product of condensation from the burning of fresh bamboo stems. We previously identified the anti-oxidant capacity of BCL in hepatocytes and suggested that BCL is a promising therapeutic candidate for treating oxidative stress-induced hepatocellular damage. Despite the importance of the role played by Kupffer cells in liver disease, the efficacy of BCL on Kupffer cells is unclear. Therefore, this study aimed to determine whether BCL could suppress LPS-induced inflammation and LPS+ATP-induced inflammasomes in Kupffer cells. Methods : We used ImKCs, a murine immortalized Kupffer cell line to examined whether BCL inhibited LPS-induced inflammation response and oxidave stress. And, we prepared a total of 18 L of BCL, purchased from Bamboo Forest Foods Co., Ltd. (648 Samdari, Damyang-eup, Damyang-gun, Jeollanam-do, Republic of Korea), was concentrated using a decompression concentrator. Result : The LPS-induced release of inflammatory cytokines was abolished by BCL treatment. Also, BCL treatment suppressed the LPS+ATP-induced expression of inflammasome proteins (NLRP3, IL-1, and IL-18), and inhib β ited the release of IL-1 . BCL decreased LPS-or LPS+ATP-induc β ed reactive oxygen species production. In addition, BCL increased nuclear translocation of Nrf2 and the expression of HO-1 in a time-dependent manner. Conclusion : These results suggest the efficacy of BCL with respect to its anti-inflammatory and anti-inflammasome effects mediated by Nrf2 in Kupffer cells.

• International Commerce and Information Review
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• v.15 no.2
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• pp.207-232
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• 2013

FTA(Free Trade Agreement) of South Korea and European Union(EU) took effect from July 1, 2011. Korea signed a contract FTA with the European Union by first among Asian country, and Korea EU FTA is evaluated that it is wide, comprehensive and high level FTA. Therefore, Korea EU FTA will become FTA that dimension is high, and FTA fermentation with the European Union may activate the Korean economy through extension of export. By the way, in Korea EU FTA, the stipulations on import and export clearance system is different compared with other FTA. Therefore, exporter and importers should compare thoroughly on essential factor of origin standard and preferential tariff which is set in FTA Agreement. In this study, I analyzed 'conditions of direct transport' that is prescribed in article 13 of Korea EU FTA. Particular, I analyzed recently example of appeal for review that decision is made in the Korea Customs Service(KCS). Laying stress on counter measure of business, conclusion in this study is as following. First, companies must understand correctly a single consignment and a single transport document under Korea EU FTA. Second, companies must not analyze wrong 'conditions of direct transport'. Third, when simplicity transshipment or temporary custody is consisted, companies must secure documentary evidence as soon as possible. Fourth, in case goods pass third country, companies must understand uprightly 'a single consignment'. Finally, companies should keep in mind to truth that European Union and EFTA are different FTA.

• Journal of the Ergonomics Society of Korea
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• v.32 no.3
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• pp.279-291
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• 2013

Objective: The aim of this study was to compare old standard EN 954-1 and new standard EN ISO 13849-1 through case study and provide necessity of adaptation of EN ISO 13849-1 in Korea. Background: International and EU harmonized standard EN ISO 13849 "safety of machinery - Safety-related parts of control system" is classified into Part 1: General principles for design and Part 2: Validation. EN ISO 13849-1 standard was introduced in Official Journal of the European Union on September 8, 2009 as harmonized standard, and old standard EN 954-1 was withdrawn on December 31, 2011. So, EU decided to use of EN ISO 13849-1 standard forcibly from January 1, 2012 for safety of machinery. New machines need to be CE marked if they are to be placed on the market in the European Economic Area(EEA), Switzerland or Turkey, and Korean machine builder should apply EN ISO 3849-1 standard for safety of machinery accordingly. However, current Korean Safety Certification system(KCs mark) for dangerous machinery is not referred to EN ISO 13849-1 standard as safety standard. There is a need of research for adaptation of EN ISO 13849-1 standard in Korea as safety standards for new design of safety-related control system which use mostly electronic components. Method: Five case studies of representative designs for safety-related control system in accordance with EN 954-1were selected according to safety category from B to 4. And these five representative designs were tried to change new design in accordance with EN ISO 13849-1 standard. The results of comparison were analyzed in aspect of economy and technical complexity. Results: The results showed that EN ISO 13849-1 provided quantitative method of application and it enabled designers to create safety-related control systems that require fewer components and less wiring, with many of the components being to a lower specification and, therefore, less costly. Conclusion: EN ISO 13849-1 standard is good for electronic safety-related control systems compare to EN 954-1. By considering the importance of application of EN ISO 13849-1 and benefits, the application of EN ISO 13849-1 as safety standard for safety of machinery is urgent in Korea. Application: The results of comparing EN 954-1 and EN ISO 13849-1 standard might help to determine the adaptation of EN ISO 13849-1 standard for safety of industrial machinery in Korea.