• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.157-162
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• 2005

Parallel implementation and performance assessment of the grid assembly in a structured chimera grid approach is studied. The grid assembly process, involving hole cutting and searching donor, is parallelized on the PC cluster. A message passing programming model based on the MPI library is implemented using the single program multiple data(SPMD) paradigm. The coarse-grained communication is optimized with the minimized memory allocation because that the parallel grid assembly can access the decomposed geometry data in other processors by only message passing in the distributed memory system such as a PC cluster. The grid assembly workload is based on the static load balancing tied to flow solver. A goal of this work is a development of parallelized grid assembly that is suited for handling multiple moving body problems with large grid size.

• 산업경영시스템학회지
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• 제20권43호
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• pp.1-16
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• 1997

This paper improves the autonomy for supplier's schedule and the flexibility of the final assembly line. The final assembly line is a single work station and each product taking different assembly time is considered. In the assembly schedule, the heuristic method based on the goal chasing method is used. Consequently, suppliers can independently determine their output rates and thus, change their workload pattern according to their needs and priorities. Moreover, this flexibility can help to avoid expensive final-assembly-line stoppages in case of sudden part supply disruptions. The sequencing method can be easily implemented into an existing just-in-time system. In addition, the mathematical model was formulated and the algorithm was explained through the flow chart. The numerical example was given and the efficiency of this method is shown through the analysis of computational results of that example.

• 대한토목학회논문집
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• 제44권5호
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• pp.707-717
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• 2024

최근 산업현장에서 발생하는 안전사고를 줄이기 위한 해결책으로 무인화 및 자동화 기술 도입이 적극적으로 고려되고 있다. 그러나 교량 시공 현장은 날씨와 지형과 같은 현장의 복잡성과 작업이 반복적이거나 표준화되기 어렵다는 점 때문에 다른 산업에 비해 관련 연구개발이 어려운 영역으로 인식되고 있다. 본 논문에서는 철근 조립, 콘크리트 타설, 고소에서의 거푸집 해체 및 조립과 같은 작업으로 인해 고위험 작업 환경으로 여겨지는 교각 시공에 있어 무인 및 자동화 시공을 위한 거푸집 시스템을 개발하였다. 이를 위해, 거푸집은 수동으로 이루어지던 해체 및 조립 과정을 대체할 수 있도록 전동 스핀들과 자동 승하강 시스템을 적용하였다. 또한, 상부 작업대에는 철근 조립 및 콘크리트 타설 작업을 대체할 수 있는 매니퓰레이터를 도입하였다. 제안된 기술의 검증을 위해, 가조립 테스트를 통해 교각 무인 시공을 위한 자동화 거푸집 시스템의 가능성을 입증하고자 하였다.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1556-1568
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• 2021

The plate-type fuel assembly adopted in nuclear research reactor suffers from complicated effect induced by non-uniform irradiation, which might affect stress conditions, mechanical behaviors and thermal-hydraulic performance of the fuel assembly. This paper is the Part II work of a two-part study devoted to analyzing the complex unique mechanical deformation and thermal-hydraulic characteristics for the typical plate-type fuel assembly under irradiation effect, which is on the basis of developed and verified numerical thermal-fluid-structure coupling methodology under irradiation in Part I of this work. The mechanical deformation, thermal-hydraulic performance and Mises stress have been analyzed for the typical plate-type fuel assembly consisting of support plates under non-uniform irradiation. It was interesting to observe that: the plate-type fuel assembly including the fuel plates and support plates tended to bend towards the location with maximum fission rate; the hot spots in the fuel foil appeared at the location with maximum thickness increment; the maximum Mises stress of fuel foil was located at the adjacent location with the maximum plate thickness increment et al.

• 산업공학
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• 제18권2호
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• pp.136-147
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• 2005

This paper introduces a simulation study regarding the operation of the Painted Body Storage (PBS) in an automobile factory. In the paint shop of the factory, same colored bodies are grouped together in order to increase the effectiveness of process, for example decrease the loss of cleaning the painting-gun when the color of body changes from one to another. However the production of automobiles in the assembly shop is a typical example of the mixed model assembly production. Therefore PBS locates between the paint shop and the assembly shop for control the input sequence of bodies to the assembly shop, and it enables to meet the smoothing requirement of assembly sequence. There are highly restricted constraints on the assembly sequence in a assembly shop. Those are spacing restriction and smoothing restriction. If such restrictions are violated, conveyor-stop or utility work will be necessary. Thus the major objective of PBS is to control the assembly sequence in a way to meet the two restrictions. In this paper a case study of PBS in an automotive factory is introduced. The storage/retrieval algorithms are suggested and the proposed system is verified using simulation models. Sensitivity analysis for operating factors is also conducted.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2009년도 추계학술대회
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• pp.131-135
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• 2009

This paper considers the sequencing of products in car assembly lines. The sequence which minimizes overall utility work in car assembly lines reduce the cycle time and the risk of conveyor stopping. The sequencing problem is solved using Tabu Search. Tabu Search is a heuristic method which can provide a near optimal solution in real time. The performance of proposed technique is compared with existing heuristic methods in terms of solution quality and computation time. Various examples are presented and experimental results are reported to demonstrate the efficiency of the technique.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2001년도 제17회 학술발표회 논문초록집
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• pp.90-93
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• 2001

In the present work, ultrasonic testing method has been developed to evaluate adhesive layers in rocket motor case assembly for the reliability of the rocket. The main objective of the present work was to find debonding between steel and rubber layers. The relationship between adhesion ratio and reflected ultrasonic amplitude was calculated by considering reflection coefficient at the interface between steel and rubber layers. It was found that the higher amplitude of ultrasound is reflected for the debonding area, and shown good agreements with experimental results. The ultrasonic C-scan images offers good implements for the determination of debonding area. The nondestructive testing results were compared with the micrography of destruective testing. As results, ultrasonic testing could be utilized for the evaluation of adhesive layer in the rocket motor case assembly.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.349-352
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• 1988

In this study, a structured supervisory control for automatic assembly system is developed. And also diagnosis and fault-recovery capability of this supervisory control are discussed. This structured supervisory control is actually applied to Die Bonding Machine and is proved to be useful and to work well.

• 한국산업보건학회지
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• 제26권4호
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• pp.426-435
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• 2016

Objectives: The major objective of this study was to analyze stress response after a change to consecutive day shifts from day and night shifts in a motor assembly factory. Methods: Using a survey conducted by a labor union, we collected data on stress response index(SRI), lifestyle factors, work-family conflict and job stress before and after a shift system change. We analyzed the transition on the SRI among 222 workers. The cut-off point for the SRI was a T-score over 60. Results: The high risk stress response group was 20.3% of the population before the shift system change. After the shift system change it decreased to 11.3%. After the shift system change, social support improved, leisure time became more sufficient, work-family conflict declined, and sleep quality in the night shift week improved. In multivariable linear regression, among workers under 40 years old sleep quality on night shift, leisure time sufficiency, social support and work-family conflict contributed to the improvement of stress response. Among workers over 40, work-family conflict contributed to the improvement of stress response. Conclusions: The change to consecutive day shifts improved stress response and mediated with improved nighttime sleep, decreased work-family conflict, increased leisure time and improved work-family conflict.

• 한국산업융합학회 논문집
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• 제13권4호
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• pp.219-225
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• 2010

A structure of line for producing products is variously changing to be automatic and one-person Cell-Line considering the physical burden for workers in manufacturing industry of electronic goods. However, workers tend to still accuse Work-related Musculoskeletal Disorders (including shoulder, waist, hand, wrist, leg etc.) as a simply repeated work by accelerating of the production speed for productivity improvement in the assembly line. Thus manufacturing engineers in charge of changing and set up newly for an assembly line are necessary to the construct of the guideline on human engineering. Especially. There is no standardized engineering-guide and it is difficult to create the exact work environment because the risk factor analysis and the improvement for assembly line are executed once a year on the current situation. I'd like to reduce the physical burden on workers through the effective improvement of processing by the guideline on working environment fit for a characteristic on manufacturing process when the process is changed or newly installed.