• Bulletin of the Society of Naval Architects of Korea
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• v.2 no.1
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• pp.20-23
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• 1965

우리나라는 연해(沿海)에 풍부(豊富)한 수산자원(水産資源)을 가진 동서남(東西南)의 삼해(三海)에 면(面)해서 멀리 탁 트인 태평양(太平洋)을 바라보는 위치(位置)에 있다. 이와같은 지리적(地理的)인 조건(條件)을 구비(具備)하고 있는 우리로서 어찌 바다에 관심(關心)을 갖지 않을 수 있겠는가? 풍부(豊富)한 수산자원(水産資源)이 있음에도 "배"의 부족(不足)으로 마음껏 이를 획득(獲得)하지 못함은 실(實)로 안타까운 일이다. 건국이래(建國以來) 조선산업(造船事業)에 힘을 기우려 이를 발전(發展)시켜왔으나 아직도 수요량(需要量)에 미달(未達)하여 약(約) 256,000여톤(餘屯)의 선박(船舶)이 부족(不足)한 실정(實情)에 있으며, 매년(每年) 1,3000여만불(餘萬弗)의 외화(外貨)가 선박운임(船舶運賃)으로 지출(支出)되는 현시(現時)에, 조선(造船)에 여러가지 애로(隘路)가 많다고 좌수방관(座手傍觀)하고만 있을 수는 없다. 이웃나라의 일본(日本)은 자국선박(自國船舶)뿐 아니라 널리 선박수출(船舶輸出)의 해외시장(海外市場)을 가지고 연간(年間) 200여만톤(餘萬屯)의 건조량(建造量)을 자랑하고 있다. 그러나 우리의 역사(歷史)위에도 통일신라시대(統一新羅時代)의 해양제패(海洋制覇)의 기록(記錄)과 임진란당시(壬辰亂當時) 우리해군(海軍)의 활동(活動) 등 우리선조(先祖)들이 그분들의 손으로 건조(建造)한 선박(船舶)으로써 활약(活躍)한 바 있고 지금의 우리도 차츰 조선업(造船業)을 부흥(復興)시켜 현재(現在) 4,000톤급(屯級)의 선박(船舶)을 건조(建造)하는 단계(段階)에 이르고 있는 것이다.

• Journal for History of Mathematics
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• v.22 no.2
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• pp.117-130
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• 2009

This study shows how to use effectively construction and solution of the quadratic equation developed by mathematicians such as Gyung Sun-jing, Hong Jung-ha, Hong Dae-yong, Lee Sang-hyuk, and Nam Byung-gil through mathematics history of Chosun Dynasty. Mathematics history of Chosun Dynasty can be used in order to enhance comprehension and increase interest in an introduction to the quadratic equation. It also can be used to help motivate middle school students to solve the quadratic equation with much interest during the development phase, and develope conceptual thinking and reflective thinking in the practical phase.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.8
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• pp.1434-1440
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• 2008

Performance of TCP/IP is studied on the wireless network using flow control and congestion control mechanism based on transmission rate. We discuss the elimination or the reduction of various phenomena of burst by flow controlling on transmission rate and verify that there are TCP ACK compression promblems on the queue by burst reaction while executing transmission rate controlled channels. Analyzing periodic burst reaction on the queue of source IP, the maximum value of queue is expected, which represents the applible expectation of throughput reduce and shows the improvement of performance by the reduce of throughput due to hi-directional traffic.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.4
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• pp.291-297
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• 2019

Polyurethane foam is the most efficient, high-performance insulation material, used for liquefied natural gas carrier (LNGC) insulation. Because LNGC is exposed to sloshing impact load due to ship motion of 6 degrees of freedom, polyurethane foam should be sufficient dynamic properties. The dynamic properties of these polyurethane foam depends on temperature and density. Therefore, this study investigates the dynamic response of polyurethane foam for various temperature($25^{\circ}C$, $-70^{\circ}C$, $-163^{\circ}C$) and density($90kg/m^3$, $113kg/m^3$, $134kg/m^3$, $150kg/m^3$) under drop impact test with impact energy of 20J, 50J, and 80J. For dynamic response was evaluated in terms of peak force, peak displacement, absorb energy, and the mechanical property with minimized density effects. The results show the effect of temperature and density on the polyurethane foam material for the dynamic response.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.2
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• pp.152-160
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• 2019

In this study, we propose a piping material supply management method using CAD system. The piping materials installed in super large offshore plants have very complicated connection conditions. Therefore, it is very difficult to determine the order of receipt of a large number of installation materials. Therefore, we have developed a system that can automatically check the preparation rate of installation materials prior to the installation process. We have developed an algorithm to obtain connection information among installation items from PDMS system. We have developed an algorithm that can determine the order of installation materials to be installed using the connection information. The order of the installation material is determined by taking into account the constraint conditions for the complete installation of the piping material. We confirm the effectiveness of the developed algorithms in the operating system. This system is also used to manage installation schedules and plan the installation manpower.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.1
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• pp.32-39
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• 2021

Korean coastal fishery suffers from profitability degradation due to a decrease in fisheries resources, pollution in coastal waters, fuel coast increase, and market opening for aquaculture products. The next generation Korean fishing vessel aims at the improvement of energy efficiency, enhancement of crew welfare, and safety. These purposes can be accomplished by adopting a new standard hull form with improved resistance performance and a modernized residence facility on the deck. In order to improve resistance performance, this study attempts to optimize design variables for stern flaps for three kinds of fishing vessels - coastal multi-purpose, coastal trap, and dredged nets. A series of model tests for these fishing vessels was carried out in the towing tank of Pusan National University. The results indicate that for some cases, the stern flap caused the stern trim of the vessel to decrease, leading to the resistance reduction.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.6
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• pp.381-387
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• 2020

According to the increase of concern for environmental problems, the energy saving becomes an important issue because it is one of the most effective methods of decreasing CO2 which is major environmental problem. In the present study, the post device after propeller related with rudder has been focussed. Recently the full-spade twisted rudder has been frequently used not only to increase the efficiency but also to remove the cavitation risk on leading edge. In addition to that the rudder bulb is also applied to the rudder to increase the propulsion efficiency as well as to minimize the cavitation erosion risk around twisting part. The parametric study has been conducted for investigating the optimum configuration of twisting rudder with bulb by CFD. The present optimization has been applied to the KVLCC2 full-body ship. The verification of the computed results is also expected to be conducted by the comparison with experimental results in the near future.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.2
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• pp.118-124
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• 2022

Marine environment analysis and ship motion prediction during ship navigation are important technologies for safe and economical operation of autonomous ships. As a marine environment analysis technology, there is a method of analyzing waves by measuring the sea states through images acquired based on radar(radio detection and ranging) signal. However, in the process of deriving marine environment information from radar images, noises generated by external factors are included, limiting the interpretation of the marine environment. Therefore, image processing for noise removal is required. In this study, image inpainting by partial convolutional neural network model is proposed as a method to remove noises and reconstruct radar images.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.1
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• pp.48-56
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• 2023

This paper implements many-to-many communication between users and develops a multi-functional smart helmet for worker protection and environmental safety in the shipbuilding and shipping industry. First, the communication situation is recorded in the field to perform signal processing for noise that interferes with communication. Then, it deals with the contents of developing smart helmets, data acquisition, algorithms, and simulations. The simulation results analyzed by applying the adaptive algorithm are shown, and their usefulness is confirmed. In conclusion, looking at the optimization process for the convergence factor of the Least Mean Square and Filtered-x Least Mean Square Adaptation Algorithm was possible. It is thought that it has laid the foundation for implementing many-to-many communication, the function of smart helmets that reduces or removes various noises at the shipyard in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.131-133
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• 2021

The Annals of the Joseon Dynasty are important records registered in UNESCO. This paper proposes a method to analyze big data by examining the frequency of words in the Annals of the Joseon Dynasty translated into Korean. When you access the Annals of the Joseon Dynasty from an Internet site and try to investigate the frequency of words, if you directly access the source included in the page, the keywords necessary for the HTML grammar are included, so that it is difficult to analyze big data based on the frequency of words in the necessary text. In this paper, we propose a method to analyze the text of the Annals of the Joseon Dynasty using Java's Jsoup crawling function. In the experiment, only the Taejo part of the Annals of the Joseon Dynasty was extracted to verify the validity of this method.