• 산업경영시스템학회지
• /
• 제29권1호
• /
• pp.63-71
• /
• 2006

In this paper, we consider a planning problem arising from printed circuit board manufacturing industries. Given a set of several types of PCBs, component feeders and surface mounting machines in series in a PCB assembly line, the problem is to define the feeder allocation and job sequence with the objective of minimizing the total operation time of the line. We formulate the problem as a mathematical model. And, the problem is proven to be NP-hard, so a genetic algorithm is developed. Finally, we give test results to evaluate the performance of the genetic algorithm.

• 한국정보과학회:학술대회논문집
• /
• 한국정보과학회 2003년도 가을 학술발표논문집 Vol.30 No.2 (3)
• /
• pp.547-549
• /
• 2003

위성의 개발 및 제작에는 많은 비용과 기간이 소요되며. 일반적으로 사용되는 장비들과는 전혀 다른 우주환경에서 임무를 수행하게 된다. 그리고 위성의 경우에는 발사이후에 발생하는 오류들을 수정하는 것이 거의 불가능하므로 위성의 성공적인 임무완수를 위해서는 철저한 사전검증 작업들이 필요하게 된다. 특히, 위성의 궤도, 자세를 제어하고 실제적인 임무수행을 관할하는 위성탑재소프트웨어에 대한 완벽한 검증이 필요하다. 이러한 소프트웨어의 통합 및 조립시험. 검증시험을 위해 저궤도 위성의 FSW(Flight Software) 개발단계에서 실제 위성시스템과 유사한 인터페이스를 제공하는 개발도구인 STB(Software Test Bed)가 제작되며, 제작된 STB를 통한 FSW의 검증시험 및 분석을 지원하기 위한 구문분석프로그램으로 VTSP(Verification Test Script Parser)를 개발하게 된다. 본 논문에서는 이러한 STB와 VTSP에 대한 전반적인 소개와 함께 개발된 STB와 VTSP를 이용하여 실제 위성탑재소프트웨어를 검증하기 위한 시험환경에 대해 알아보고자 한다.

• 대한안전경영과학회:학술대회논문집
• /
• 대한안전경영과학회 2005년도 춘계학술대회
• /
• pp.523-534
• /
• 2005

This paper is concerned with the integrated problem of line balancing and model sequencing in mixed model assembly lines(MMALBS), which is important to efficient utilization of the lines. In the problem, we deal with the objective of minimizing the overall line length To apply the GAs to MMALBS problems, we suggest a GA representation which suitable for its problems, an efficient decoding technique for the objective, and genetic operators which produce feasible offsprings. Extensive experiments are carried out to analyze the performance of the proposed algorithm. The computational results show that our algorithm is promising in solution quality.

• 대한안전경영과학회지
• /
• 제5권1호
• /
• pp.69-82
• /
• 2003

The sequence which minimizes overall utility work in car assembly lines reduces the cycle time, the number of utility workers, and the risk of conveyor stopping. This study suggests mathematical formulation of the sequencing problem to minimize overall utility work, and present a genetic algorithm which can provide a near optimal solution in real time. To apply a genetic algorithm to the sequencing problem in car assembly lines, the representation, selection methods, and genetic parameters are studied. Experiments are carried out to compare selection methods such as roullette wheel selection, tournament selection and ranking selection. Experimental results show that ranking selection method outperforms the others in solution quality, whereas tournament selection provides the best performance in computation time.

• 대한인간공학회:학술대회논문집
• /
• 대한인간공학회 1997년도 추계학술대회논문집
• /
• pp.433-436
• /
• 1997

Automobile assembly tasks consist of many kinds of manual work which are very stressful to workers because of repetitive poor working postures and dealing heavy weights. To decrease the level of workload, it is necessary to evaluate the workload quantitatively. In this study, a workload evaluation method based on EMG was experimentally evaluated. We measured EMG at 6 main muscles with 2 healthy male workers during doing 9 assembly tasks, which were selected as high workload jobs. The tasks were decomposed into 36 elementary tasks. The workload was calculated through an equation with %MVIS and work duration time. To evaluate the result, subjective discomfort on the tasks was assessed by 29 workers. By the calculated workload, we were able to ranked the workload of tasks, elementary tasks. The comparison between the EMG-based workload and subjective rating showed a positive correlation(P-value=0.0246). We think it is possible to adapt the EMG-based workload evaluation technique to all assembly tasks by expending the experi- ment size.

• 대한인간공학회지
• /
• 제29권6호
• /
• pp.951-957
• /
• 2010

The purpose of this study is to identify the types and features of job rotation being operated in a motor company. The types of job rotation have been classified according to the range of rotation and its cycle. Also, the features of the favorable rotation types were examined by the worker's age and their types of tasks. The results show that workers prefer broader ranges and slower cycles of rotations as they age. Moreover, older workers tend to show an increase in the preference of participating in job rotations. The result of this study is expected to be applied as fundamental data to job design.

• 한국생산제조학회지
• /
• 제20권3호
• /
• pp.322-328
• /
• 2011

This paper presents inverse kinematics and workspace analysis of a planar three degree-of-freedom (DOF) parallel manipulator. Furthermore, optimization problem of the manipulator is presented. The manipulator adopts PRR (Prismatic-Revolute-Revolute) mechanism and the prismatic actuators are fixed to the base. This leads to a reduction of the inertia of the moving links and hence enables it to move with high speed. The actuators are linear electric motors. First, the mechanism based on the geometry of the manipulator is introduced. Second, a workspace analysis is performed. Finally, design optimization is carried out to have large workspace. The proposed approach can be applied to the design optimization of various three DOF parallel manipulators in order to maximize their workspace. The performance of mechanism is improved and satisfies the requirements of workspace to align micro-components.

• 대한안전경영과학회지
• /
• 제7권3호
• /
• pp.85-96
• /
• 2005

This paper is concerned with the integrated problem of line balancing and model sequencing in mixed model assembly lines(MMALBS), which is important to efficient utilization of the lines. In the problem, we deal with the objective of minimizing the overall line length To apply the GAs to MMALBS problems, we suggest a GA representation which suitable for its problems, an efficient decoding technique for the objective, and genetic operators which produce feasible offsprings. Extensive experiments are carried out to analyze the performance of the proposed algorithm. The computational results show that our algorithm is promising in solution quality.

• 대한인간공학회지
• /
• 제25권3호
• /
• pp.61-66
• /
• 2006

Awkward work postures in workshop highly affect on work-related musculoskeletal disorders(WMSDs). Especially, in automobiles assembly process, these awkward work postures of workers may cause serious injury and illness. This study is to compare the performance among the evaluation tools which can measure the work-loads caused by the awkward work postures in automobiles assemble process. RULA, REBA and TVAL(Toyota Verification of Assembly Line) are used as the evaluation tools. The 85 jobs selected in the automobiles assembly process are applied to the three tools and their performances are analyzed after the evaluation of the work-load in each job. Through various measures of performance such as statistical test, DUNCAN test, regression test etc., the tendencies and characteristics among them are analyzed in detail.

• 한국산학기술학회:학술대회논문집
• /
• 한국산학기술학회 2001년도 춘계학술대회 발표논문집
• /
• pp.241-244
• /
• 2001

스냅핏은 일종의 결속장치로서 흔히 플라스틱 부품들을 서로 체결하는데 이용되는데, 다른 결속장치에 비해 간편하고 생산품의 조립단가를 줄일 수 있고, 또한 분리력은 큰 반면에 결합력은 작게 만들 수 있는 장점을 가지고 있어 널리 사용된다. 스냅핏의 설계는 재료에 따른 물성(property) 및 구조적 강성(stiffness)이 설계 초기단계에서 고려되어야 하고, 또한 사출성형공정에서 스냅핏의 성형성도 예측되어야 한다. 그러나 스냅핏의 형상, 치수, 위치 등을 적절히 설계합성(synthesis)하고 적절한 재료를 선택하는 작업은 공정에 관한 종합적인 지식을 지원해 주는 합리적인 설계도구가 제공되지 못했던 이유로 사출 전문가의 오랜 기간 축적된 경험과 지식에만 전적으로 의존하여 왔다. 본 연구에서는 기존의 전문가에 의존해온 스냅핏 설계방법을 개선하기 위해 사출성형에 의해 제한되어지는 지식을 규칙베이스화하고 재료의 물성과 스냅핏의 형상 및 치수에 파라 스냅핏이 갖는 결합력, 분리력, 변형하중 및 허용언더컷 등을 출력하는 지적 설계 프로그램을 제안하였다.