• Bulletin of the Society of Naval Architects of Korea
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• v.53 no.4
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• pp.27-34
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• 2016

현재 국내 대부분 조선소에서는 선박 외판 곡 가공 작업시 곡률이 작은 부재는 일반 낱개 형상의 목형 틀을, 선수 및 선미 구간 중 곡률이 큰 부재는 입체 형상의 목형 틀을 제작하여 선상 가열 작업 중 이를 참조하여 철판의 곡형을 생성한다. 이 중 입체형상의 목형 틀을 상형곡형이라고 한다. 이러한 상형곡형 제작정보를 생성하는 방법은 각 조선소마다 조금씩 다르기는 하지만 대부분이 수작업에 의해서 목형 제작정보를 생성한다. 현장 작업자가 선형도면을 직접 참조해서 작도 및 계산을 통하여 입체형상에 대한 각각의 정보를 수작업으로 산출하거나 또는 설계 작업자가 입체형상 구성에 필요한 모든 단면을 개별적으로 모델링하여 제작정보를 현장에 제공한다. 이 과정에서 작업 공수가 과다 소요되며 수작업에 의한 제작정보 오류가 종종 발생하여 외판 곡 가공 공정에 문제가 발생하기도 한다. 그렇기 때문에 본 연구에서는 상형곡형 제작에 필요한 생산 정보를 설계 작업자 또는 현장 작업자 어느 누구라도 쉽고 간단하게 산출할 수 있도록 생산지원 시스템을 개발하였다. 이로 인해 상형곡형 제작이 필요한 외판부재의 경우 즉시 제작정보를 산출하여 제작하도록 함으로써 작업시간을 비약적으로 절감이 가능하게 될 것이다.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.58-58
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• 2009

선박의 선체부분인 선수, 선미 등을 이루고 있는 곡형 외판의 제작은 강판을 원하는 형상으로 성형하기 위하여 벤딩롤러 및 유압프레스를 이용한 냉간가공과 산소-프로판가스 화염을 적용한 선상가열, 삼각가열을 이용한 열간가공으로 크게 구분할 수 있다. 선상가열을 이용한 곡면가공의 원리는 가열토치를 이용하여 강판을 가열하면 가열부는 팽창하게 되고 냉각시에는 수축하게 된다. 이 때 두께방향으로의 소성변형으로 인한 수축량의 차이로 인해 굽혀지게 된다. 최근에는 선박이 고기능 및 대형화로 인해 3차원 곡형 외판 형상이 복잡해지고, 강도를 향상시키기 위하여 합금원소(C, Nb, V, Ti)를 첨가하거나 열처리(노말라이징)를 이용한 고장력강재인 중후판의 적용이 증가하고 있다. 이러한 고강도강재를 선상가열공정으로 제작한 곡형 외판재는 가열, 냉각의 열사이클로 인해 취화되어 인성이 저하 될 수 있다. 본 연구에서는 Normalizing 열처리재인 490MPa급 강재를 이용하여, 현장에서 작업자의 미숙련으로 인해 발생 할 수 있는 최대의 가혹한 조건과 재질에 큰 영향을 미치지 않는 범위를 선정하여 선상가열시의 가열, 냉각조건에 따른 강재의 재질특성을 조사하고자 한다. 이를 위해 가열시 가열부위의 정확한 온도 측정에 역점을 두었으며, 각각 다른 선상가열 조건에 따른 시편을 제작하기 위하여 선상가열 실험장치를 제작하였다. 선상가열 실험 결과 최고가열온도 $1300^{\circ}C,\;950^{\circ}C$에서 수냉 조건인 경우 급격한 인성저하 현상이 발생하며 비록 공냉이라 하더라도 결정립 조대화로 인성 저하가 발생하였다. $800^{\circ}C$가열 후 수냉개시온도를 $700^{\circ}C$이하로 수냉한 경우에는 인성 저하 현상이 개선되고 있음을 알 수 있다.

• Proceedings of the KOR-KST Conference
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• 1996.06a
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• pp.95-128
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• 1996

Dipped track profiles between rail transit stations can significantly reduce propulsive energy, braking energy and travel times. This work quantifies their potential benefits for circumstances reflected in various values for dips, speed and acceleration limits, station spacings, and available power. A deterministic simulation model has been developed to precisely estimate train motions and performance using basic equations for kinematics, resistance, power and braking. For a dip of 1% of station spacing, in which gradients never exceed 4%, our results show savings (compared with level tracks) exceeding 9% for propulsive energy, 15% for braking energy and 5% for travel time between stations.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.2
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• pp.136-143
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• 2018

3-D templates are produced to evaluate completeness of the shell plates during the forming process, which is an essential step for the ship production. They are mostly produced in advance during the detail/production design stage, but occasionally they are requested by the shell plate forming department, because it is impossible to predict accurately the necessities of them at the design stage. This results in a huge loss of man-hour and a bottleneck. In order to resolve this issue while reducing the dependence on other department, the process of manufacturing the 3-D templates needs to be automated. Therefore, this study proposes an automatic system that calculates the manufacturing information of the 3-D templates with only geometric information of the shell plates. The system considers the thickness and the cutting method of the parts of the 3-D templates and some options are provided to reflect the intention of the worker.

• Special Issue of the Society of Naval Architects of Korea
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• 2011.09a
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• pp.32-35
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• 2011

Template has been widely used for hull forming process in most of shipyards. It is used to estimate the curvature of deformed shape in comparison with design shape. SHI (Samsung Heavy Industry) had used AutoKon system for ship manufacturing design in the past. The AutoKon used the global coordinate system of ship (frame, water line and so on) to create template data. It brought the mismatched angles between templates and a curved shell plate. The mismatched angle is measured by forming worker to place template on shell forming stage. However, the mismatched angle is difficult to place template with exactly required angle because the shell plates have various curvature and size. It causes incorrect shape of formed shell plates. The attached angle of template should be 90 degree to place template easily on forming shell plates. Currently, SHI has been applied GSCAD for ship manufacturing design process which is 3D solid modeling system. The GSCAD is the rule-based system which can automate 3D modeling and control the manufacturing data by rule. The rule can easily provide methods to create and automate template object with regular attached angle in comparison with AutoKon system. Therefore, SHI developed new template rule which it can automatically create template object with regular attached angle in GSCAD.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.4
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• pp.317-324
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• 2016

Stress tests were conducted in the carbody of the railroad car to check the structural strength of the body of the railroad car. The objective of this study was to evaluate safety of the carbody of a railroad car under the maximal strength. The carbody of rolling stock is a principal structure that supports major equipment of the underframe and the freight. Therefore, the strength evaluation of this structure is important. This study was carried out to analyze the structure of carbody and evaluate safety under maximum vertical load, compressive load, and torsional load. Accordingly, stress tests were conducted on the carbody to measure the stress on each of their parts. Before the load test, a structural-analysis program was used for the stress distribution analysis of the body structure.

• The Korean Journal of Ecology
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• v.1 no.2
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• pp.49-56
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• 1977

For the culture the population growth, shell length and spawning seasons of Gomphina veneriformis, and its environmental factors, were investigated at the Jeju coastal regions. from Feburuary, 1975 to March, 1976. The soil movements of the tidal flats where the clams inhabited were relatively rapid during the strong tidal actions. The rate of population growth were rapid from April to September, then became obsure. The relative growth equations of the shell height (SH) and the shell breadth (SB) against the shell length (SL) of the clams were as follows: Changhung : SH=0.751 SL + 0.685, SB=0.448 SL-0.630 Pyoson : SH-0.775 SL - 0.115, SB=0.464 SL-1.008 Hwhason : SH=0.794 SL - 0.923, SB=0.485 SL-1.155 Kwhagzee : SH=0.771 SL - 0.644, SB=0.455 SL-1.049 The meat weight increases of the clams were continued from March to late June, then it decreased sharply up to late August. The spawning of the clams seems to be late from June to Spetember in the regions studied.

• Korean Journal of Computational Design and Engineering
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• v.17 no.6
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• pp.426-435
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• 2012

This paper starts with an approach to Korean traditional building design using BIM tool as a design methodology where Korean traditional buildings show some difference rather as weaknesses in handling curves and curved members and the construction. BIM design tools, that are adequate in treating modern architectural design vocabularies, show some disadvantages not having necessary elements and components as building libraries. In this paper we build our own libraries adequate to the proper assembling way of Korean traditional buildings. In contrast to the diverse use of straight building members, Korean traditional buildings show rare use of curves and/or curved members in their assemblage. Moreover, in the case of a circular plan, mostly a circle is interpreted in terms of polygons such as square, hexagon or octagon. In this paper, we examine Gwanram-Jung in Changduk Palace, which is probably the only example in Korea showing a use of curves and/or curved members in assemblage. We try to interpret the case as an incomplete prototype and apply in a modern way to complete a circular plan in terms of circular arcade.

• Journal of the Korean housing association
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• v.21 no.5
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• pp.137-144
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• 2010

The purpose of this study is to clarify locational characteristics and the road systems of existing 22 old settlements in Cheongju downtown of Korea. These old settlements are classified largely into two types by geographical feature; Hill type located in ridge and Valley type in the valley from the ridge. The Hill type is further categorized into San-rock located on ridge and Gogae located on hillside, and the Valley type into closed large and small valley, that is, Daegok and Sogok by the shape and size of the valley. The road systems are classified into outer road, approaching road, inner road, and side road. In San-rock type villages, Inner road is changed side roads by new arterial road, and new ones become inner road. The outer road are almost cut off, but side roads maintain. In the case of the Gogae type, main road becomes inner road, maintain old hierarchical road, and in other cases, villages are formed around side roads derived from main road, and outer road and inner road are cut off. Among the Valley type, Daegok type maintains old hierarchical road, while for Sogok type, outer roads are cut off, and new roads are outer road.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.3
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• pp.233-238
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• 1990

Weedy rice(red rice) collected in Korea were crossed with the Japonica, Javanica and Indica tester cultivars, and also crossed among those collected lines. Their seed fertility was counted and refered to their cross affinities. Some tester cultivars such as, Suweongjo, Malagkit Sinaguing and wx 817 which were regarded as belong to the Japonica, Javanica and Indica respectively, showed the typical tendencies of hybrid sterility when they were crossed each other. But, other testers such as Kwanak, Tapaiko, Belle Patna and Tarichaosun showed some differencies from those typical patterns, implying some varigations within a ecotype. The hybrids of weedy rice crossed to the Japonica testers showed higher fertility with a few semisterilities. While the crosses of weedy rice to the Javanicas or Indicas showed high sterility implying closer affinity relationships of weedy rice to the Japonicas. Even those weedy rice lines such as Samsanmyeon 8 and Sanchungaengmi B which showed semi-sterility when they were crossed to the Japonica testers showed high sterility when they were crossed to both Javanicas and Indicas. The hybrids among weedy rice lines showed high fertility raning 69% to 96%. Even those weedy rice lines which showed semi-sterility in the crosses with Japonica testers, showed high-fertility when they were crossed with those weedy rice lines. Though the amylose content, Alkali Digestive Value, Phenol reaction and grain shapes of theose weedy rice lines showed divers variations, the cross affinities of them showed closer phylogenie relationship to the Japonicas than to Japvanicas or Indicas. But the genetic influinces of Indicas to those weedy rices were not ignorable.