• 산업공학
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• 제12권3호
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• pp.395-400
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• 1999

Shipbuilding process is composed of hull construction, in which the structural body of a ship is formed, and outfitting, in which all the non-structural parts such as pipes, derricks, engines, machinery, electrical cable, etc. are manufactured, added and assembled. Hull construction can be classified into parts fabrication, block assembly and hull erection. Among them, the parts fabrication is the first manufacturing stage that produces components or zones needed for block assembly and hull construction. More specifically, the parts fabrication is performed through machining processes including marking, cutting, pressing, and/or forming. When material is entering into the parts fabrication stage, it is important for achieving the total efficiency of production to select one of production division, so-called 'bay,' as well as machine tools on which the part is fabricated. In this paper, given production quantities of parts in the fabrication stage, the problem is to optimally select machine tools and production division, such that the total flow-time is minimized as well as the workload among machines is balanced. Specifically, three mathematical models for flow-time minimization, load balance, and simultaneously considering both objectives, and a numerical example are analyzed and presented.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.425-429
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• 2002

It has been used many kinds of horizontal butt-welding methods at block-to-block erection stage in shipbuilding companies. For examples, some companies use conventional FCA W process with one side or both sides groove joint welding, others use carriage with torch holder type mechanized welding method. Although lots of efforts were done until now, some problems in quality and productivity still remain in ship's hull welding. In this study, we have attempted to raise productivity and quality on horizontal position of welding with following 3 items. 1) Prepare groove condition with no root gap for making easy fit-up work. 2) Develop improved MAG (100% $CO_2$ gas shielding) welding process with solid wire for making sound root bead from one side. 3) Develop and apply quite new automatic welding carriage. The stability of new welding process was confirmed by conducting mechanical tests of weldments to verify the soundness of weldments.

• 한국CDE학회논문집
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• 제17권1호
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• pp.17-25
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• 2012

Recently, requests for accurate process planning using simulation have been increasing in many engineering fields including the shipbuilding industry, and many application systems for simulation have been developed. It is difficult, however, for a user to reuse the developed systems, because simulation models in the system are defined by its own method. In addition, the simulation model should be modified whenever a simulation sequence, which is called simulation scenario, is changed. Therefore, in this study, an elementary simulation object is proposed to modularize a simulation model. And the management scheme of simulation scenario is proposed to manage the scenario outside of the simulation models. Also, a simulation template is proposed to increase the development efficiency. To verify the efficiency of the proposed methods, application examples for shipbuilding process planning are implemented.

• Journal of Welding and Joining
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• 제28권1호
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• pp.54-59
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• 2010

Ship Blocks are assembled by welding, and among them, welding between large blocks (Pre-erection stage) is used as feature of butt. In this process, local material has a experience of thermal cycle and become finally shrunk. As for inconsistency of shrunk weldments and adjacent regions, ship structure would be deformed locally and globally. Thermal distortion analyses are done for control of these processes, and methodologies capable of ship block size among them are using 2-D shell element in FEM. A shell element takes charge of plate, so it has its thickness which is important for angular distortion by welding. By the way, a butt-welding consists normally of several passes, and weldment thickness are different at each pass. If a calculated final one-time welding shrinkage is acting on the shell element whose thickness is same as it of plate, then deformation value must be underestimated. This research developed a methodology that total deformation after multi-pass welding can be analyzed by one time at shell element having original thickness of its plate. We use the SDB thermal distortion analysis method and verified by several experiment. The both experimental and analysis results showed good agreements.

• International Journal of Korean Welding Society
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• 제3권1호
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• pp.34-38
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• 2003

It has been used many kinds of horizontal butt-welding methods at block-to-block erection stage in shipbuilding companies. For examples, some companies use conventional FCAW process with one side or both sides groove joint welding, others use carriage with torch holder type mechanized welding method. Although lots of efforts were done until now, some problems in quality and productivity still remain in ship's hull welding. In this study, we have attempted to raise productivity and quality on horizontal position of welding with following 3 items. 1) Prepare groove condition with no root gap for making easy fit-up work. 2) Develop improved MAG (100% $CO_2$ gas shielding) welding process with solid wire for making sound root bead from one side. 3) Develop and apply quite new automatic welding carriage. The stability of new welding process was confirmed by conducting mechanical tests of weldments to verify the soundness of weldments.

• 대한조선학회논문집
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• 제44권1호
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• pp.48-54
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• 2007

Higher productivity and less cost during the manufacturing process of ships are required to maintain international competitiveness of modern shipbuilding industries. The integrated hull/ outfitting/ painting scheduling(IHOP) process is a final point, where logistics are finally being integrated and upcoming schedules are made. Therefore, more profits are expected from IHOP by effective management. In this thesis, IHOP is proposed in order to solve how to choose block erection date with IHOP scheduling logic. The result of IHOP scheduling is highly advised to utilize fabrication, outfitting shops. A standardized operation and load of resource will eventually be applied in long-term time span point of view for this will make it easy to enable capacity planning and workforce planning. It is also expected to eliminate inefficiency in overtime work and efficiently utilize manpower in short-term.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 춘계학술대회 논문집
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• pp.47-50
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• 2002

선반건조 일정계획에 있어서 탑재 공정은 전체 생산일정 계획 중 선박 한 척에 대한 계획의 시발점이 되며, 병목현상 등을 유발하여 다른 일정에 가장 큰 영향을 주게 되는 공정이다. 최근 많은 조선소에서 하나의 Dock 내에서 두 착 이상의 배를 동시에 건조하는 tandem 방식을 택하고 있어 dock 내의 한정된 Crane 의 개수와 Crane의 Capacity, 공수 등의 자원, 그리고 작업환경에서 일어날 수 있는 여러 가지 변수들을 제대로 고려하지 못 했을 시에는 일정의 차질과 Dock의 회전율을 떨어트리게 한다. 본 논문에서는 가상공간에 하나의 Dock 를 만들어서 일정계획에서 작성한 Network를 사용하여 실제 작업하게 해서 그 Network가 현장에서의 최적한가를 점검하게 하고 현장에서 수정하는 작업을 줄이게 하는 것의 방법으로 simulation을 개발하였다.

• The Korean Journal of Pain
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• 제8권2호
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• pp.336-340
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• 1995

Impairment of erectile function, although normally a benign disorder, has a profound impact on the well-being of many men. Penile erection is produced by a complex series of events involving cognition, peripheral sensory input, central and peripheral autonomic nervous events and hormonal vascular events. The multiplicity of potential determinants identified suggest that impotence does not inexorably accompany age, but it is an arugmented significantly modifiable paraaging phenomena. A 53 year old male patients developed sudden impotence. The patients did not respond to intracavernous injection of papaverine. This patient was successfuly treated with 4 repeated stellate ganglion blocks.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2001년도 학술대회지
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• pp.214-221
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• 2001

인천국제공항 교통센터의 Great Hall은 3차원의 입체적 곡면 Truss로 구성되어 있고, Great Hall Roof Truss는 최대 경간162m, 480Ton인 Truss을 포함한 13개의 Main Steel Truss로 구성되어 있다. Great Hall Roof Truss는 총 중량 6,300Ton, 9,600 Pieces로 1개의 절점당 최대 13개의 다른 부재가 접합하게 되어 있고, 12개의 Fabric 기초에 의해 지지된다. 경제적인 효과와 공기적 측면을 고려하여 기존 재래식(가설 Bent) 공법보다 Block화 공법 및 Sliding공법을 채택하였다. Roof 구조물은 3,550Ton과 2,700Ton 중량인 두 Block으로 나누고 구조물 외부에 설치 된 Giant Sleigh에 선 조립 후 Tandem Pulling Jack과 Strand를 이용하여 181m를 Sliding하여 본 구조물의 위치에 설치되었다.

• 한국산업보건학회지
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• 제25권4호
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• pp.472-481
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• 2015

Objectives: Welding is a major task in shipbuilding yards that generates welding fumes. A significant amount of welding in shipbuilding yards is done on steel. Inevitably, manganese is present in the base metals being joined and the filler wire being used and, consequently, in the fumes to which workers are exposed. The objective of this work was to characterize manganese exposure associated with work area, total and particle size-selective mass concentration, and compare the mass concentrations obtained using a three-piece cassette sampler, size-selective impactor sampler and blood manganese concentrations. Materials: All samples were collected from the main work areas at one shipbuilding yard. We used a three piece cassette sampler and the eight stage cascade impactor sampler for the airborne manganese mass concentration of total and all size fractions, respectively. In addition, we used the results of health examination of workers sampled for airborne manganese. Results: The oder of high concentration of airborne manganese in shipbuilding processes was as follows; block assembly, block erection, outfitting installation, steel cutting, and outfitting preparation. The percentages of samples that exceeded the OES of the ministry of employment and labor by the cassette sampling method was 12.5%, however 59.1% of sampled workers by the impactor sampling method exceeded the TLV of the ACGIH. Conclusions: Even though the manganese concentrations in blood of workers exposed to higher airborne manganese concentration were higher than among those exposed to lower concentrations, there was no difference in blood manganese concentrations among work duration. The data analyzed here by characterizing size-selective mass concentrations indicates that the inhaled manganese of welders in shipbuilding yards could be mostly manganese-containing respirable particle sizes.