• Title/Summary/Keyword: Jeong Yag-yong

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Jeong YagYong's Perceptions of Sea Refugees and Maritime borderlines (다산 정약용의 표류민과 해상국경에 대한 인식)

  • Shin, Jae-Hoon
    • Strategy21
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    • pp.215-240
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    • 2015
  • Jeong YagYong, who are the SilHak Scholar during 18th to 19th century, wrote the Sadaegore with his pupil Lee Cheong. This work is the guide of diplomacy, which are asked to write from King Jeongjo. Although this book was completed after King Jeongjo's death, it harbors the King's thoughts about diplomacy or the relationship with China. Haebanggo, one chapter of the book, is about marine policy and how to treat the castaways. In this chapter, Jeong YagYong provides various ways to deal with these problems in marine area and sea refugee I will examine the Jeong YagYong's thought about the problems and ways to address these problems. Futhermore, I will inquire Jeong's opinion on the boundary in marine area. He recognized that many border transgressions happened in marine area at that time and considered that as urgent political affairs. Haebanggo consists of two parts. First part of the book is about protect own island from other countries. The rest part is about cases of dealing with castaways and their transgression. I argue that Jeong YagYong intended to make distinct borderlines in marine area and empathized the necessity of protecting Joseon's islands from other countries.

An Analysis of the Contents and Expression Methods of Jeong Yag-yong's 『Gugo Wonlyu』 (정약용의 『구고원류』의 내용과 표현방법 분석)

  • Lee, Kyung Eon
    • Journal for History of Mathematics
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    • v.29 no.1
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    • pp.1-16
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    • 2016
  • This study analyzes the contents and expression methods of Jeong Yag-yong's "Gugo Wonlyu". The 530-page long "Gugo Wonlyu" discusses 1541 formulas about Gu, Go, Hyun, Hwa, Gyo; however, it has only the results of formulas and no explanations about their inducement method. Therefore we do not know how he derives and verifies the formulas. In addition, it did not follow the basic form of oriental mathematics textbooks: problem-answer-solution, and presented all the formulas only with characters without using numbers. This is a very distinctive aspect compared to other mathematical textbooks. In addition, the formulas about 5-Hwa and 5-Gyo are addressed exactly in fixed order and covers a formula in various directions. This is a clear evidence that Jeong Yag-yong analyzed and studied the Gugosul thoroughly.

Gugo Wonlyu of Jeong Yag-yong (정약용의 구고원류)

  • Kim, Young Wook
    • Journal for History of Mathematics
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    • v.32 no.3
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    • pp.97-108
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    • 2019
  • This paper is an outgrowth of a study on recent papers and presentations of Hong Sung Sa, Hong Young Hee and/or Lee Seung On on Gugo Wonlyu which is believed to be written by the famous Joseon scholar Jeong Yag-yong. Most of what is discussed here is already explained in these papers and presentations but due to brevity of the papers it is not understood by most of us. Here we present them in more explicit and mathematical ways which, we hope, will make them more accessible to those who have little background in history of classical Joseon mathematics. We also explain them using elementary projective geometry which allow us to visualize Pythagorean polynomials geometrically.

Mathematical Structures of Polynomials in Jeong Yag-yong's Gugo Wonlyu (정약용(丁若鏞)의 산서(算書) 구고원류(勾股源流)의 다항식(多項式)의 수학적(數學的) 구조(構造))

  • Hong, Sung Sa;Hong, Young Hee;Lee, Seung On
    • Journal for History of Mathematics
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    • v.29 no.5
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    • pp.257-266
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    • 2016
  • This paper is a sequel to our paper [3]. Although polynomials in the tianyuanshu induce perfectly the algebraic structure of polynomials, the tianyuan(天元) is always chosen by a specific unknown in a given problem, it can't carry out the role of the indeterminate in ordinary polynomials. Further, taking the indeterminate as a variable, one can study mathematical structures of polynomials via those of polynomial functions. Thus the theory of polynomials in East Asian mathematics could not be completely materialized. In the previous paper [3], we show that Jeong Yag-yong disclosed in his Gugo Wonlyu(勾股源流) the mathematical structures of Pythagorean polynomials, namely polynomials p(a, b, c) where a, b, c are the three sides gou(勾), gu(股), xian(弦) of a right triangle, respectively. In this paper, we show that Jeong obtained his results through his recognizing Pythagorean polynomials as polynomial functions of three variables a, b, c.

Mathematical Structures of Jeong Yag-yong's Gugo Wonlyu (정약용(丁若鏞)의 산서(算書) 구고원류(勾股源流)의 수학적(數學的) 구조(構造))

  • HONG, Sung Sa;HONG, Young Hee;LEE, Seung On
    • Journal for History of Mathematics
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    • v.28 no.6
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    • pp.301-310
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    • 2015
  • Since Jiuzhang Suanshu, the main tools in the theory of right triangles, known as Gougushu in East Asia were algebraic identities about three sides of a right triangle derived from the Pythagorean theorem. Using tianyuanshu up to siyuanshu, Song-Yuan mathematicians could skip over those identities in the theory. Chinese Mathematics in the 17-18th centuries were mainly concerned with the identities along with the western geometrical proofs. Jeong Yag-yong (1762-1836), a well known Joseon scholar and writer of the school of Silhak, noticed that those identities can be derived through algebra and then wrote Gugo Wonlyu (勾股源流) in the early 19th century. We show that Jeong reveals the algebraic structure of polynomials with the three indeterminates in the book along with their order structure. Although the title refers to right triangles, it is the first pure algebra book in Joseon mathematics, if not in East Asia.

Finite element analysis for prediction of bead shape of Nd:YAG laser butt welding (Nd:YAG 레이저 맞대기 용접의 비드형상 예측에 관한 유한요소해석)

  • Kim, Kwan-Woo;Nam, Gi-Jeong;Lee, Jae-Hoon;Suh, Jeong;Cho, Hae-Yong
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.1
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    • pp.137-146
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    • 2008
  • Nd:YAG pulse laser welding of stainless steel plate was simulated to find welding condition by using commercial finite element code MARC. Due to geometric symmetry, a half model of AISI 304 stainless steel plate was considered and user subroutines were applied to boundary condition for the heat transfer. Material properties such as conductivity, specific heat, mass density and latent heat were given as a function of temperature. As results, Three dimensional heat source model for pulse laser beam conditions of butt welding has been designed by the comparison between the finite element analysis results and experimental data on AISI 304 stainless steel plate. Nd:YAG laser welding for AISI 304 stainless steel was successfully simulated and it should be useful to determine optimal welding condition.

Finite Element Analysis of Nd:YAG Pulse Laser Welding for AISI 304 Stainless Steel Plate (AISI 304 스테인리스 강판의 Nd:YAG 펄스 레이저 용접에 관한 유한요소해석)

  • Nam Gi-Jeong;Kim Kwan-Woo;Hong Jin-Uk;Lee Jae-Hoon;Suh Jeong;Cho Hae-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.4
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    • pp.428-434
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    • 2006
  • Pulse laser welding of AISI 304 stainless steel plate was simulated to find optimal welding conditions by using commercial finite element code MARC. Due to geometric symmetry, a half model of AISI 304 stainless steel plate was considered and user subroutines were applied to boundary condition for the heat transfer. Material properties such as conductivity, specific heat, mass density and latent heat were given as a function of temperature. A moving heat source was designed on the basis of experimental data. As a result, Nd:YAG laser welding for AISI 304 stainless steel was successfully simulated and it should be useful to determine optimal welding condition.

Finite Element Analysis for Prediction of Bead Shape of Nd:YAG Laser Fillet Welding (Nd:YAG 레이저 필렛 용접의 비드형상 예측에 관한 유한요소해석)

  • Kim, Kwan-Woo;Lee, Jae-Roon;Suh, Jeong;Cho, Hae-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.8
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    • pp.839-846
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    • 2007
  • Nd:YAG pulse laser fillet welding of stainless steel plate was simulated to find welding condition by using commercial finite element code MARC. Full model of AISI 304 stainless steel plate was considered and user subroutines were applied to boundary condition for the heat transfer. Material properties such as conductivity, specific heat, mass density and latent heat were given as a function of temperature. As results, Three dimensional heat source model for pulse laser beam conditions of fillet welding has been designed by the comparison between the finite element analysis results and experimental data on AISI 304 stainless steel plate. Nd:YAG laser welding for AISI 304 stainless steel was successfully simulated and it should be useful to determine optimal welding condition.

The characteristics of Surface Transformation Hardening for Rod-shaped SM45C Carbon Steel by CW Nd:YAG Laser (CW Nd:YAG Laser를 이용한 SM45C 환봉의 표면 열처리 특성)

  • Kim Jong-Do;Gang Un-Ju;Lee Chang-Je;Lee Je-Hun;Seo Jeong;Lee Mun-Yong
    • Proceedings of the KWS Conference
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    • pp.248-250
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    • 2006
  • The study on a surface transformation hardening of a rod-shaped SM45C carbon steel is carried out by using CW Nd:YAG laser. Conventionally, $CO_2$ laser has been usually used as a laser source for a transformation hardening. however, it is needed to an additional absorbent coating like a colloidal graphite owing to a lower absorbtion rate. On the other hand, no cost and post-removal process of coating is required to Nd:YAG laser, due to a higher absorbtion rate relatively. Moreover, there is a merit which is capable of building up the more flexible processing system resulted from a beam delivery through a optical fiber. In this study, we were going to recognize characteristics of a transformation hardening using a optic head with a gaussian beam distribution.

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