• 한국안전학회지
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• 제27권3호
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• pp.131-140
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• 2012

Though there might exist not a few differences between cyclic works and atypical works, many researchers have applied the same assessment techniques that used for repetitive works, which may result introduce bias in their conclusions. This research aimed to verify whether there exist non-negligible work characteristics and/or dissimilarity among works with different work nature and whether one of the most prevalent assessment techniques for assessing ergonomic hazards of musculoskeletal disorders, REBA, can be applied to atypical works. For a general hospital, an automobile repair shop, and two auto-part assembly plants which manufactures quite different parts, a questionnaire survey and field investigation and ergonomic assessment were carried out and analyzed statistically with reference to the 3rd Quantification technique. The results showed that there exist remarkable difference between physical factors in cyclic works and atypical non-cyclic works. As for repetitive work, body posture was significant factors affecting on musculoskeletal disorders while atypical works seemed to have none which implied that the necessity of taking psychosocial factors into account for assessment of hazards. Complain rate in repetitive works was highest shoulder, back, and neck or wrist in sequence. However, there existed no consistent trend in complain rate in atypical works. And, though weight of manufacturing objects was a common factor that can partly explain musculoskeletal complain, time duration was significant in atypical work whereas repeatability and body posture were significant in repetitive works. As being the results, to summarize, it could be said that application of conventional ergonomic assessment techniques regardless of repetitiveness would be fruitless, and that the necessity of a unique methodology focused on atypical non-cyclic works should not be neglected.

• 한국시뮬레이션학회논문지
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• 제21권1호
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• pp.69-79
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• 2012

대량 맞춤화 생산에서 목표 중 하나는 생산 비용이나 제품 인도 스케줄을 크게 변화시키지 않고 특정 고객의 요구를 만족시키는 생산을 달성하는 것이다. 조선 항공과 같은 대형 조립-생산 산업에서의 맞춤화는 이에 따른 부품이나 또는 부품의 중간조립품인 모듈의 변화를 가져오게 된다. 본 연구는 조선 분야에서의 사례 연구를 통하여 고객의 맞춤화에 따른 생산 스케줄의 변화가 선박 인도에 미치는 영향을 분석하고자 한다. 대단위 조립 생산에서 대량 맞춤화는 맞춤화의 요구 수준에 따라 엔지니어링 및 조립-생산 시간이 변화한다. 본 연구는 조선 산업에서 처음으로 대량 맞춤화를 수행하는 생산 방안을 제안하고 이론적조선 생산 과정을 간략히 기술한 시뮬레이션 모형을 통하여 다양한 수준에서의 대량 맞춤화가 선박 인도 일정에 어떠한 영향을 미치는가를 평가하였다.

• 시스템엔지니어링학술지
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• 제16권1호
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• pp.68-77
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• 2020

The shipbuilding and offshore industry is a large and complex assembly industry, which causes many safety accidents. The major accidents in the shipbuilding and offshore industry workplaces are stenosis, falling objects, dust, fire, explosions, and gas poisoning. The accident by worker in this industry mainly has three factors: frequent movement, narrow work space, and increased use of subcontractors. To control these factors, it is necessary to monitor the worker's location and work status. In this paper, a worker location monitoring system using inaudible sound wave was designd that can be used in environments with many metal barriers. The process included deriving stakeholder requirements, transforming to system requirements, designing system architecture, and developing prototype. The prototype was validated by third-party testing agency. As a result, it satisfied the designed performance and verified its feasibility.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.581-584
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• 2008

A generation of a particle beam is the key technique in a flow cytometry that measures the fluorescence and light scattering of individual cell and other particulate or molecular analytes in biomedical research. Recent methods performing this function require a laborious and time-consuming assembly. In the present work, we propose a novel device for the generation of an axisymmetrical focusing beam of microparticles (3-D focusing) in a single capillary without sheath flows. This work uses the concept that the particles migrate toward the centerline of the channel when they lag behind the parabolic velocity profile. Particle focusing of spherical particles was successfully made with a beam diameter of about 10 ${\mu}$m. Proposed device provides crucial solutions for simple and innovative 3-D particle focusing method for the applications to the MEMS-based micro-flow cytometry. We believe that this device can be utilized in a wide variety of applications, such as biomedical/ biochemical engineering.

• 한국정보시스템학회:학술대회논문집
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• 한국정보시스템학회 1996년도 추계학술발표회 발표논문집
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• pp.217-227
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• 1996

The new field of learning control develops controllers that learn to improve their performance at executing a given task, based on experience performin this specific task. In a previous work［6］, the authors presented a theory of indirect learning control based on use of indirect adaptive control concepts employing simultaneous identification ad control. This paper develops improved indirect learning control algorithms, and studies the use of such controllers in decentralized systems. The original motivation of the learning control field was learning in robots doing repetitive tasks such as on an assembly line. This paper starts with decentralized discrete time systems, and progresses to the robot application, modeling the robot as a time varying linear system in the neighborhood of the nominal trajectory, and using the usual robot controllers that are decentralized, treating each link as if it is independent of any coupling with other links. The basic result of the paper is to show that stability of the indirect learning controllers for all subsystems when the coupling between subsystems is turned off, assures convergence to zero tracking error of the decentralized indirect learning control of the coupled system, provided that the sample time in the digital learning controller is sufficiently short.

• Design & Manufacturing
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• 제2권4호
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• pp.54-61
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• 2008

Warpage, which is one of the molding trouble, acts as possible factor which results in defect in assembly. In this study, a mold was designed to produce specimens with rib parallel to flow direction, specimens with rib perpendicular to flow direction and specimens without rib. This work researched change of warpage according to injection molding condition such as injection pressure, packing pressure, packing time, resin temperature, mold temperature in non-crystalline resins(PC, ABS), crystalline resins(PP, PA66), and 30% glass fiber reinforced-resins(PC, ABS, PP, PA66).Specimens with rib and Crystalline resins show more warpage than specimens without rib and non-crystalline resins, respectively. Glass fiber reinforced-resins and specimens with rib parallel to flow direction show smaller warpage than conventional resins and specimens with rib perpendicular to flow, respectively. Specimens with rib and specimens without rib show reduced warpage as packing time increases. In addition, warpage increase as resin temperature increases. It is found that CAE shows similar tendency with experiment as packing time, resin temperature. when the rib is caused, warpage will reduce and prevent the transformation. product of a irregular form occurs warpage. In the study It'll be basic data that product occurs warpage, preferablity.

• 경영과학
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• 제10권2호
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• pp.121-143
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• 1993

Traditional Manufacturing method is push system by plan made in advance and Japanese manufacturing method represented by JUST-IN-TIME is pull system which respond's to the demand flexibly. Both have their pros and cons. In general, it is well understood that push system is faster than pull system in the sense of manufacturing speed. However, pull system such as JIT excelles dramatically in the sense of work in process. Therefore, this paper is trying to put together to get alternative which has the advantage of both system. The objective of the paper is to enhance the effect of built-in manufacturing system without paying extra cost by way of introducing the alternative of the pull-push manufacturing strategic operational method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.968-973
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• 1991

Seven axis modular type pneumatic manipulator is composed of electro-pneumatic automation system which contributes to factory automation by performing loading & unloading process successively which is simple routine work of dealing item of machine tool, catapult, assembly machine, welding machine and so on. In this study, we obtained soft and quick movement in a large space and good reliability motion of various function by combining several actuators which perform rotation movement as well as linear movement at the same time. Gripper which apply to rotary sensor transmitted a structure to demanded position. This development item of 5kgf load prevent stick-slip phenomena of stroke end by designing high cushion internal. We develope flexible manipulator which conforms to demand of user by applying multiple sequence program.

• Bulletin of the Korean Chemical Society
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• 제26권3호
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• pp.418-422
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• 2005

By introducing spin-coating method to the evaporation induced self-assembly (EISA) process, a simple and reproducible route in controlling the mesophase of silica thin films has been developed for the first time in this work. When a comparatively solvent-rich Si-sol (The atomic ratio of TEOS : F127 : HCl : $H_2O$ : EtOH = 1 : 0.006 : 0.2 : 9.2 : 30) was used as coating solution, the mesophase of resultant silica films was selectively controlled by adjusting the spin-on speed. The cubic mesophase has been obtained from the coating at a low rpm, such as 600 rpm, while the 2-D hexagonal mesophase is formed at a high rpm, such as 2,500 rpm. At a medium coating speed, a mixture of cubic and hexagonal mesophase has been found in the fabricated films. The present results confirm that the evaporation rate of volatile components at initial step is critical for the determination of mesopore structures during the EISA process.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.412-412
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• 2000

This paper presents a task teaching method for off-line programming of a multi-robot system. Teaching commands were developed in order to simplify a complex teaching process, to shorten the setup time for new working environment and to have flexibility for changes in working environment. Four teaching commands can be used to automatically generate trajectories of an end-effector of the robot in electronics assembly line. The robots used in the work cell are a four-axis SCARA robot and six-axis articulated robot. Each robot is controlled in a independent way while objects, working environment and robots are modeled in corresponding modules, respectively. The off- line programming system developed uses OpenGL for a smooth graphic effect in Window s where three dimensional CAD data can be leaded for graphical modeling.