• 한국자동차공학회논문집
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• 제16권5호
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• pp.8-14
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• 2008

For nondestructive inspection of electron beam (EB) welding part in automotive power transmission assembly, a pulse-echo ultrasonic testing apparatus in water immersion has been applied using the ultrasonic waves with a frequency of 10MHz. However various problems have appeared during the ultrasonic inspection, which led to some significant mistakes in automatic quality evaluation of the welding parts. Experimental study showed that the state of water couplant medium containing some amount of contaminants, rusts and anti-corrosion agents had considerable influences on the reduction of ultrasonic amplitudes during wave propagation. The amplitude reduction depending on the coupling medium state could bring about some mis-diagnoses for defects in the welding parts. The results proposed that for a reliable inspection of defects in welds the state of water medium should be kept in about 15 volume fractions (vol.%) of anti-corrosion agents and in minimized contaminants.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.637-642
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• 2008

The concept of district heating involves centralised heat production where heat is distributed to consumer via a piping network. The objective of this work is to identify the Flexible Pipe from an economy, execution, maintenance point of view. Flexible Pipe has in some countries, especially in Europe, been used for many years in district heating. In spite of years of experience, there still exist doubts about the possibilities of using flexible pipes in district heating applications, mostly because of no experiences in domestic market. The advantage of flexible pipe systems is their flexibility. This holds not only for the inner pipe but also for the total pipe system including insulation and jacket. Even for the largest diameter the minimum radius of curvature is given to 1.5m. The most important difference between flexible pipe systems and preinsulated steel pipes is their simple and quick assembly. Such information could provide a basis for making reasonable hypotheses about consumer preferences, to foam a basis for making future marketing more effective.

• Animal cells and systems
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• 제6권4호
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• pp.327-333
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• 2002

Among the silk glands in the black widow spider Latrodectus mactans, the ampullate one is the most predominant gland in both sexes, and is com-posed of three functional parts - excretory duct, storage ampulla and convoluted tail regions. This experiment was performed using mechanical pulling stimulation with electric motor equipment to reveal a correlation between silk usage and silk producing system in this poisonous spider. The mature secretory products in glandular epithelium are closely packed and appear as electron-opaque spherical vesicles. A part of the vesicles with fine fibrillar paracrystalline texture seems to store some proteins which will function at the time of final assembly into fibrils. Most of the secretory silk products which originated from the rough endoplasmic reticula of the glandular epithelial cells are grown by fusion with surrounding small vesi-cles. However, the Golgi complex does not seem to play an important role in this process of secretion. According to progressive maturation of secre-tory silk product, these granules are progressively filled with a fine fibrillar material, and thus appear much more electron-dense than those of earlier states. When the secretory product is extruded from the glandular cavity, the epithelium is rapidly changed to a thinner layer of tall columnar cells with less definitive cell membranes. After extruding there ave a few secre-tory droplets within these cells, thus causing this region to stain much lighter.

• 전자공학회논문지B
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• 제32B권11호
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• pp.1393-1404
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• 1995

For the factory automation(FA) of production or assembly lines, computer vision techniques have been widely used for the recognition and position-control of objects. In this application, it is very important to analyze characteristic features of each object and to find an efficient matching algorithm using the selected features. If the object has regular or homogeneous patterns, the problem is relatively simple. However, If the object is shifted or rotated, and if the depth of the input visual system is not fixed, the problem becomes very complicated. Also, in order to understand and recognize objects with concentric noise patterns, it is more effective to use feature-information represented in polar coordinates than in cartesian coordinates. In this paper, an algorithm for the recognition of objects with concentric circular noise-patterns is proposed. And position-conrtol information is calculated with the matching result. First, a filtering algorithm for eliminating concentric noise patterns is proposed to obtain concentric-feature patterns. Then a shift, rotation and scale invariant alogrithm is proposed for the recognition and position-control of objects uusing invariant feature information. Experimental results indicate the effectiveness of the proposed alogrithm.

• 대한산업공학회지
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• 제41권5호
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• pp.470-480
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• 2015

There are many challenges in manufacturing system for new factory construction. Although factories produce same product, the layout of each factory may be different. The body shop in an automotive factory is a typical flow line with assembly, but the layout concept of the line varies among factories. In this paper, two types of layouts in the body shops of automotive factories, one for layered build and the other for modular build, are compared using simulation study. The simulation experiments indicate that the modular build layout is better than the layered build layout with respect to production rate. The effects of various failure distributions on the throughputs are also investigated, and some insights are suggested regarding the layout concept.

• 대한조선학회논문집
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• 제42권2호
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• pp.165-174
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• 2005

Recently, world leading companies on manufacturing field are trying to adopt a PLM methodology, which is a new production paradigm, for a survival and strengthening the competitiveness. Some projects for a digital shipyard including a methodology of a digital simulation framework are going on by Seoul national university and Samsung heavy industry. A Database methodology for a scheduling data, an interfacing methodology for a simulation input and output, and a synchronized simulation related methodology are required for enhancing the value of the digital simulation for shipbuilding. In this paper, such a methodologies and a related case study for a fabrication factory and an assembly factory are presented.

• 한국시뮬레이션학회논문지
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• 제19권2호
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• pp.107-118
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• 2010

자동차 제조업은 수천 가지의 다른 구성품 또는 부품의 조립이 필요한 복잡한 생산시스템이다. 엔진과 트랜스미션은 자동차의 동력을 담당하는 주요 구성품이다. 엔진의 경우 생산공정이 대부분 유사한 공정들로 구성되어 있음에도 불구하고 공장별로 생산시스템의 배치안은 상이하다. 그 이유는 각 공장마다 기계들을 어떠한 직렬구조와 병렬구조를 조합하여 배치하는지에 대한 개념이 다르기 때문이다. 이 논문에서는 서로 다른 공장에서 적용하고 있는 세 종류의 엔진 라인을 소개한다. 그리고 시뮬레이션을 이용하여 각 라인의 설계개념이 라인의 성과에 미치는 영향에 대해 비교분석하고자 한다.

• 한국가축번식학회지
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• 제27권3호
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• pp.197-206
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• 2003

hFSH는 $\alpha$와 $\beta$ subunit으로 구성된 heterodimer로서 두 subunit의 조합은 활성을 지닌 호르몬의 생산에 있어서 매우 중요한 단계이다. 이 조합과정의 효율을 증대하기 위하여 본 연구에서는 hFSH를 단일사슬의 단백질로 구축하고자 하였으며, 이의 일환으로 각 subunit 대한 cDNA단편을 연결하는 서열로 CTP linker를 도입하였다. 재조합한 hFSH-CTP 유전자는 pseudotype의 retrovirus vector system을 이용하여 CHO 세포와 닭의 배로 각각 전이되었다. CHO 세포에서의 FSH의 생산은 $\alpha$와 $\beta$를 각각 전이한 경우에 비해 hFSH-CTP를 전이한 경우에서 17배 이상 높은 것으로 나타났다. 닭에서는 유전자 전이를 시도한 62개체 중에서 11마리가 부화하였으며 그 중 10마리가 형질전환된 닭인 것으로 RT-PCR을 통하여 확인되었다. 그러나 개체의 혈중 FSH의 생산은 확인하지 못하였다. 이상의 실험 결과를 바탕으로 하여 재조합된 hFSH-CTP는 FSH의 발현에 매우 효율적인 구조로 생각되며, 또한 retrovirus를 이용한 유전자 전이 방법은 형질전환 가금의 생산에 있어서 매우 적절한 방법으로 사료된다.

• 한국해양공학회지
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• 제26권5호
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• pp.63-72
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• 2012

The product lifecycle of a marine vessel can be classified into the design-production, operation-maintenance, and disposal phases. During the operation and maintenance phase, status data should be gathered from the major machinery and instruments installed on the marine vessel in order to perform efficient maintenance work. Although a PLM (product lifecycle management) system can manage the product information during the design and assembly stage, a PLM based on asset management technology is more appropriate for product information management during the operation stage. Product embedded information devices (PEIDs) are suggested for gathering real-time maintenance information during the operation and maintenance lifecycle. A PEID allows PLM to provide the capability of offering active information exchange between the lifecycle management system and equipment. This study designed a PEID to effectively obtain information and interact with a PLM system. It consists of sensors, wireless communication, and a micro-processor, which allow it to accumulate status data on the PLM system. The embedded information device and PLM enable the seamless information flow, tracking, and updating of MRO (maintenance repair and overhaul) information for a product throughout the middle of the product lifecycle.

• 한국시뮬레이션학회논문지
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• 제27권4호
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• pp.69-77
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• 2018

발사관은 탑재물을 보관하고 외부 환경으로부터 부식 및 파손되는 것을 방지하는 역할을 한다. 발사관과 유도탄의 제작, 조립 그리고 장입 상태에 따라 발사할 때 유도탄의 초기 거동을 결정하게 된다. 본 연구의 목적은 유도탄이 발사관에서 사출될 때 유도탄의 초기 거동을 결정하는 요소를 통계적으로 분석하여 발사관의 안전성을 확인하는 것이다. 유도탄이 발사될 때 거동에 영향을 주는 오차 요소들을 선정한 후 Monte-Carlo 시뮬레이션을 수행하여 통계적으로 분석하였다. 시뮬레이션 결과를 바탕으로, 각 오차 요소들을 고려한 다물체 동역학 해석을 상용프로그램인 Recurdyn을 이용하여 동역학 해석을 수행하여 유도탄 발사할 때 발생하는 중력 침하 및 레일과 슈 사이에 발생하는 응력을 구하였다. 해당 결과를 바탕으로 현재 설계된 발사관에 대한 안전성을 검증하였다.