• 한국생산제조학회지
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• 제22권5호
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• pp.795-799
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• 2013

This paper describes a novel hybrid surface polishing process combining non-traditional electrochemical polishing (ECP) with external artificial ultrasonic vibration. The purpose of this study is to develop an easier method for improving stainless steel surfaces. To this end, vibration electrochemical polishing (VECP), a novel ultrasonic manufacturing process, for enhancing electrochemical reaction and surface quality compared with that achieved using conventional ECP is suggested. In addition, for finding the optimized experimental conditions, the two methods are compared under various current densities. Localized roughness of the work material is measured with atomic force microscopy (AFM) and scanning electron microscopy (SEM) for obtaining detailed surface information.

• Journal of Advanced Marine Engineering and Technology
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• 제36권7호
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• pp.910-918
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• 2012

Carbon monoxide (CO) is a primary air pollutant as an indicator of air quality released from motor vehicle combustion. A comparative study of the distributions of CO concentration with no heat source in two tunnel models open and closed at both end sides is simulated with a commercial CFD code. The tunnel models are used to investigate the CO concentration distributions at three Reynolds numbers, which are computed by the inlet velocities of 0.3, 0.6 and 1.0 m/s. For a better tunnel design, the CFD predictive approaches are available in qualitatively studying the distributions of CO concentration. In the case of the tunnel open at both end sides in sixty seconds, the total CO concentrations are approximately twenty eight percent higher than those in the closed case.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2018년도 제57차 동계학술대회논문집 26권1호
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• pp.31-34
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• 2018

We live in the digital era, and the characteristics of our customers in the digital era are constantly changing. That's why understanding business requirements and converting them to technical requirements is essential, and you have to understand the data model behind the business layout. Moreover, BI(Business Intelligence) is at the crux of revolutionizing enterprise to minimize losses and maximize profits. In this paper, we have described a leading study about the situation of desk-top BI(software product & programming language) in aspect of front-end side and the Data Lake platform based on Big Data by data modeling in aspect of back-end side to support the business intelligence.

• 한국작물학회지
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• 제36권2호
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• pp.185-196
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• 1991

도작은 동아 습윤지 농작물의 가장 대표적인 것으로서 고금을 통하여 국가의 재정과 식량원을 조달하는 주역의 위치를 차지해 왔었다. 또한 이러한 위상은, 물론 동남아 제국을 포함하여, 중국대륙과 한반도 및 일반열도로 이어지는 지역을 중심으로 기술교류와 이해관계를 맺어오면서 형성되어 왔음에 틀림이 없다. 특히 우리나라는 지리적 위치로 인하여 더욱 두드러진 교양적 역할을 담당할 수밖에 없었고, 더우기 문화적 교체는 물론 외침과 내환을 수없이 겪는 동안 농업조건은 개간과 황폐 및 회복을 거듭하였고, 이 위에서 도작과 도작기술의 수용발전은 칠전팔기하여 왔음도 분명하다. 그럼에도 불구하고 우리나라 역사는 왕조실록을 중심으로한 조정의 기록은 풍부한 반면에 지방과 농촌의 기록은 지극히 비약한 것을 특징으로 하기 때문에 도작과 도작기술의 변천상을 알 수 있는 길 또한 지극히 제한되어 있었으며, 결국은 조선시대 초기부터 편찬되기 시작했던 농서들을 시대별로 구분하여 검토하고, 다시 종합적으로 비교고찰하면서 맥락을 더듬는 도리밖에 없다. 본 연구는 우리나라 도작기술이 여말까지 직수입 되었던 고대중국의 한전식 기술로 부터 어떻게 우리의 실정에 맞추어 성립될 수 있었고, 또한 이들로부터 독창성을 찾아 재정립된 기간은 무엇이며, 이들이 조선시대의 파란많은 내외란을 통하는 동안 어떻게 존속되고 변천해 왔으며, 이들 결과가 선말에 이르러 존속 발전하면서 치루어낸 역할이 시사하는 바가 무엇이었는지를 고찰하고자 하였다.

• 대한수학회논문집
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• 제20권4호
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• pp.861-873
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• 2005

In this paper we approximate a cylindrical helix by bi-conic and bi-quadratic Bezier curves. Each approximation method is $G^1$ end-points interpolation of the helix. We present a sharp upper bound of the Hausdorff distance between the helix and each approximation curve. We also show that the error bound has the approximation order three and monotone increases as the length of the helix increases. As an illustration we give some numerical examples.

• 한국수학사학회지
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• 제11권1호
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• pp.36-41
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• 1998

In the Chosun Dynasty Nam, Byung-Gil(another name is Nam, Sang-Gil alias Won-Sang; 1820-1869) made a research comparing Chinese traditional mathematics with western mathematics, which missionaries who came to China at the end of Ming Dynasty introduced. He particularly studied fundamental differences between Chinese and western methods to solve algebraic equations. He wrote an article "Moo-Ee-Hae", in which he insisted that the two methods are eventually same though they are different in the고 expressions. His article has big significance as the first mathematic paper in the history of Korean mathematics.thematics.

• 호남수학학술지
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• 제30권4호
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• pp.617-629
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• 2008

In this paper, the authors have found an equivalent condition of the endomorphism ring End(M) of a projective module M being von Neumann regular(Theorem 1.14) and found an equivalent condition of any associative ring R being von Neumann regular (Theorem 1.13).

• 한국가구학회지
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• 제18권1호
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• pp.1-12
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• 2007

Korea has a dark age in terms of culture in the last 20th century. Korea had been struggling between the Great Powers of the world in the imperialism and had sacrifice to keep our own culture itself. Japanese imperialist's a invasion, culture liquidation by Japan, Independence from Japan, Korean war and Influence by US are major bitter historical affair after close of Chosun Dynasty in the process of modernization. Therefore Korea couldn't stay in the center of world cultural core parts and was degraded as cultural consumption country which was provided oversea culture by other countries. Then Korea couldn't develop our unique traditional idea and culture. In the meantime there are both extreme phenomena; one is expulsion of other cultures absolutely and the other is only following western culture unconditionally like trimming policy in the end of colony age. These discreet and unfiltered western culture had been influenced Korea culture over the wide range strongly and resulted in cultural colony situation to produce western imitation culture without philosophy and traditional spirit. Even though Korea has met opportunity in the culture, we called "Han Trend", no formation of own culture is main reason for psychological panic. Korea furniture design is one of parts of lost of tradition culture and typical parts in reproducing western imitation culture. As a result furniture industry's major reason for loss value as exporting industry compared to other industries result in most of the furniture products without our unique identity. This situation become more deepen unfortunately. This report would like to suggest the direction of design with global competition capability and cultural identity to boost Korean furniture design industry by comparing, analyzing and speculating between design of Chosun dynasty and philosophy of modernism in western.

• Journal of Preventive Medicine and Public Health
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• 제5권1호
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• pp.43-48
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• 1972

5 bed sand filter, applying biological oxidation, was designed and studied on the treatment of water works. Never using any coagulant agent (drugs), which may cause water pollution in pre-treatment of head water, the auther attempt a high rate filtration by the microorganism (nitrofication bacteria) end plant which populate in multi layer sand beds. The result are as follows : In order to evaluate the oxygen effect on filtration, oxygen was injected in aeration tank attached to each filter tank while filtration, and $NH_3$ was tested as a representaiive ingredient. It was found out that the aeration method was more effective, with over 33% of $NH_3$ removal capacity, than the anerobic and this 5 bed filter showed double removal capacity of $NH_3$ by comparing with conventional sand bed (2 stage bed). According to the examination of two kind of head water, pre-treated with coagulant agent and activated carton, the filtration capacity was affected by the polluted condition of head water, resulting that lower value of pollution and slower velocity of filtration showed more efficiency of $NH_3$ removal. In this experiment $NH_3$ content tested in treated water had a fairly good correlation with others.

• 수산해양교육연구
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• 제11권1호
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• pp.69-87
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• 1999

This study had been analysed the establishment, the closing and the actual conditions of the fisheries school according to the four times revision and promulgation of the law of education of korea which were devided by the early term (the first Chosun educational decree), the middle term (the second Chosun educational decree) and the last term (the third and fourth Chosun educational decree), and also been investigated how the fisheries education of the school had been acted to the mobocracy and the assimilation policy and together with it's back ground through this analysis. The aim of this study is to contribute to the study of the history of the fisheries school education, analysis of change of the fisheries school education according to practical application of the Chosun educational decree. The summary of the characteristic of the each term are as under. First, in the early term of the fisheries education under the first Chosun educational decree, Experts were despatched to the each province with donated money from emperor and opened seasonal the fishing training centre, a kind of social fisheries education, and trained directly fishing technic and were going to train fisheries trainees regularly under name of elementary fisheries school. Japanese imperialism attached great importance to the vocational education in order to snack economical products from colonized Korea but actually had a purpose to train low quality technician who follow blindly their colony policy of Japanese imperialism. The fisheries schools in the circle of system in early time of Japanese imperialism, Kunsan public elementary fisheries school was established in April 1915, Yosu public elementary fisheries school was established ill May 1917 and Kyungnam Tongyoung training school was established in March 1917. Secondly, After 3.1 movement, the Japanese imperialism established an appeasement policy so called cultural politics and continued assimilation policy with skilful methods. After revision of the second Chosun educational decree, the Elementary vocational school was changed as the vocational training school. The school of fisheries education in middle of Japanese imperialism trained low quality technicians to snack fisheries resources from colonized Korea. After the middle of Japanese imperialism they paid attention on training fisheries technician through fisheries school rather than training school. With high interest and crowded volunteers, Kunsan public fisheries school was promoted in 1922, Tongyoung public fisheries school was promoted in 1923, Yongampo fisheries training school established in 1922 was promoted as Yongampo public fisheries school in 1926. Thirdly, in the time of the third and fourth Chosun educational decree, the end of Japanese imperialism, they met Pacific war after Japan vs China war. During the war time they considered the vocational school as the source of supply for materials and manpower and consequently had to expanded vocational education and systematically despatched students to war field and practiced military training. In 1938, Namhae public fisheries school was established and Chungjin fisheries school was permitted. But in order to supply manpower to Pacific war, the study period of Yosu public fisheries school was shorten from 5 years to 4 year in 1943 and also that of Tongyoung public fisheries school shorten in 1944.