• 한국생산제조학회지
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• 제20권5호
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• pp.653-658
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• 2011

In general, the purpose of packaging fasteners is a series of management activities to maintain the condition at the time of production until they get delivered to the end user. An automatic packing system for fasteners is consisted of bucket conveyor, slide feeder, vision inspection system, box-magazine conveyor system and automatic packing machine. Also, the automatic packing machine is consisted of six modules including charging device, clamping/opening device, sealing/cutting device, feeding/air-shower device, supplying/adjusting device and device frame, etc. In this paper, we proposed an automatic packing mechanism of the one station concept for packing work of fastener objects where the continuous batch work is performed in a finite space. The proposed one-station packing mechanism has been optimized through mechanical, dynamical, structural and fluid analyses. And it had been manufactured as the prototype of automatic packing machine. The field test for validation of performance was performed directly at the production line of bolt and screw. In the field test, this packing machine showed an efficiency of about 4.5 times the manual operation. It also showed 30% reduction in the consumption of packing materials compared to the manual operation. This automatic packing machine for fastener objects will be commercialized soon.

• 기계저널
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• 제20권1호
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• pp.64-66
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• 1980

전자업계에서는 그동안 LSI(Large Scale Integrated Circuit), Microprocessor등의 괄목한 개발로 각종 생산공장, 의료기구등의 측정, 가공, 제어 및 계산의 자동화를 가속 시켜주고 있으며 이러한 컴퓨터기능의 범용화로 우리 생활면에도 많은 변화를 가져오고 있다. 계산기의 대중보급화로 계산자(Slide Rule)가 없어지고 조그마한 계산기가 프로그램의 능력을 가짐으로서 통계는 물론, 수학에서는 편미분 방정식 까지도 쉽게 처리해 주며, 기계분야에서는 Beam의 계산, 사절기 구(Four Bar Mechanism)등도 쉽게 풀어주고 있다. 또한 토목분야 에서는 과거 숙달된 측정기 사에 의존하던 지형의 정밀측정이 측정의 자동화로 측정치가 정확하게 읽혀지고 있지만, 반면 아쉬운 점이라면 정밀측정사에 의존하던 정밀도등이 장비의 정밀도에 의존해 가는 경향도 무시 될 수 없겠다. 또한 안과에서는 과거에 시력측정표를 일정거리에 떨어져서 측정하던 시력검사가 이제는 기계를 안구에 대고 자동측정 하게 된 점 등 다 나열 할 수 없게된 현실이다. 그러면 우리 기술인 주변에는 어떠한 면들이 바뀌었는가, 우선 생산 Line의 자동화, 설계자체도 컴퓨터를 이용하는 많은 여건상의 변화가 일어나고 있다. 여기서 선진국등의 현황과 더불어 우리의 여건 진로 방향등을 잠시 고찰해 보고자 한다.

• 한국해양공학회지
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• 제15권4호
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• pp.86-91
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• 2001

In lateral ground flow, slope stability, and land slide problems, H-piles have been often used for a horizontally deforming ground to prevent the failure of mass of soil in a downward and outward movement of a slope. Here, Theoretical equations are derived to estimate the lateral force, assuming that the Mohr-coulomb's Plastic states occures in the ground just around H-piles. In this study, the mechanism of lateral force acting on passive pile that is in a row, situated in the ground undergoing plastic deformation was discussed, and its theoretical analysis was carried out considering the interval between H-piles. The solution of the theoretical equation derived from here showed resonable characteristic for constants of soil as well as for the interval, widths, and heights of H-pile.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.592-598
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• 1992

For a high bandwidth, accurate end of arm motion control with good disturbance rejection, the, Momentum Management Approach to Motion control (MMAM) is proposed. The MMAM is a kind of position control technique that uses inertial forces, applied at or near the end of arm to achieve, high bandwidth and accuracy in movement and in the face of force disturbances. To prove the concept of MMAM, the, end point, control of a flexible manipulator is considered. For this purpose, a flexible beam is mounted on the x-y table, and the MMAM actuator is attached on the top of the flexible beam. A mathematical model is developed for the flexible, beam being controlled by the, MMAM actuator and slide base DC motor. A system identification method is applied to estimate some system parameters in the, model which can not be determined because of the complexity of the mechanism. For the end point, control of the. flexible beam, the, optimal linear output feedback control is introduced.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1283-1288
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• 2008

The FPCB is used as the important component of the sliding mechanism of mobile phones. FPCB have been used as jumper cables(fixed wiring) in various types of circuits because of their flexibility and bending property. The dominant failure mode of the FPCB is open that was caused by fatigue. The fatigue is repeated whenever the sliding is open, so it is a mainly cause of FPCB fatigue. We examined the bending-fatigue lifetime of FPCB. we focused on observing the contact resistance degradation of FPCB of mobile phones according to different test condition of bending strain. As a result, it has proved that lifetime decreased by increasing bending strain.

• 한국재료학회지
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• 제34권6호
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• pp.261-266
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• 2024

Although most strains of escherichia coli (E. coli) are harmless, some serotypes can cause serious food poisoning in humans. It is very difficult to eliminate E. coli from our lives. Here we show that E. coli can be eliminated by hydroxyapatite (HAp). Because HAp has a positive charge, the material and E. coli are attracted through electrostatic interactions. Additionally, because the surface of HAp is porous, it enters the pores of the HAp surface removing them from the environment. The amount of adsorption was observed to increase over time, and the zeta potential value of the material tended to be similar to that of E. coli. This phenomenon is thought to have zeta potential similar to that of E. coli as it is adsorbed onto the HAp surface over time. E. coli stained with crystal violet was spread on a glass slide and HAp porous sol powder was dropped to remove the E. coli. We expect that this analysis will open a new direction for antibacterial materials.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제8권5호
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• pp.530-539
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• 2002

최근 정형화된 구조를 갖는 뉴스 동영상 비디오에 대한 아카이브 시스템을 구축하기 위한 많은 연구가 진행되어 왔다. 그러나 기존의 시스템에서는 기사에 대한 메타 데이타를 저장하는 방법이 서로 다르기 때문에 이런 데이타 사이의 호환성이 없다는 문제점을 가지고 있다. 본 논문에서는 이런 문제점을 해결하기 위하여 멀티미디어 내용 정보를 표현하기 위한 표준인 MPEC-7 MDS에 바탕을 둔 뉴스 동영상 스키마를 제안하였으며, 또한 기사를 이루는 각 샷들의 특징을 반영한 기사 요약 방법을 설계하고 구현하였다. 본 논문에서 제안한 뉴스 동영상을 위한 스키마는 뉴스 구조의 특성을 반영하여 MPEG-7 MDS의 VideoSegment, TextAnnotation 등과 같은 스키마를 이용하여 설계하였고, 요약 방법에서는 요약 비디오 데이타의 크기를 줄이기 위하여 샷들의 키프레임들만을 해당 오디오와 함께 상영하는 슬라이스 쇼 방법을 사용하였다.

• 한국기계가공학회지
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• 제14권6호
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• pp.111-121
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• 2015

The objective of this study is to develop an automatic object changer unit to improve changing process problems existing in the conventional horizontal machining center. In order to perform this objective, an upward and downward traverse unit was designed. This unit consists of a motor, reducer, chain and sprocket wheel, and an upper and lower base. This automatic object changer unit performs a sliding contact motion in a purpose built and designed frame. Constraint conditions for the upward and downward traverse unit were first designed. Then, an operation mechanism was designed and introduced as the sum of the kinetic energy for the sprocket wheel and the upper and lower base and which was based on the moment of inertia, which is the kinetic energy of the converted upward and downward traverse unit in the side of the reducer. The paper covers the design of th e Automatic Pallet Changer for th e machining center.

• 대한기계학회논문집A
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• 제20권6호
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• pp.1827-1835
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• 1996

This paper addresses the problem of a torch path generation for the 2D laser cutting of a stock plate nested with resular or irregular parts. Under the constaint of the relative positions of parts enforced by nesting, the developed torch path algorithm generate feasible cutting path. In this paper, the basic object is a polygon( a many-slide figure) with holes. A part may be represented as a number of line segments connected end-to-end in counterclockwise order, and formed a closed contour as requied for cutting paths. The objective is to tranverse this cutting contours with a minimum path length. This paper proposes a simulated annealing based dtorch path algorithm, that is an improved version of previously suggested TSP models. Since everypiercing point of parts is not fixed in advance, the algorithm solves as relazed optimization problem for the constraint, thich is one of the main features of the proposed algorithm. For aolving the torch path optimization problem, an efficient generation mechanism of neighborhood structure and as annealing shedule were introduced. In this way, a global solution can be obtained in a reasonable time. Seveeral examples are represented to ilustrate the method.

• Mycobiology
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• 제38권3호
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• pp.203-205
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• 2010

The spore of Tricholoma matsutake is considered to be the starting point of the mushroom growth cycle, but the mechanism of mycelial development from the spore stage is not yet clarified. In this study, we tried to measure how far the spores of T. matsutake disperse from a fruiting body located at a Pinus densiflora stand in Korea. We established 16 slide glasses coated with glycerin near a fruiting body in four directions separated by four different distance intervals within a mushroom productive stand after removing all other fruiting bodies from three plots. The number of dispersed spores increased with time from the first day (475 $spores/cm^2$) to the fourth day (836 $spores/cm^2$) after the pileus opened. The number of spores dispersed downward was about 1.5 times greater than that dispersed toward the ride. The number of dispersed spores decreased exponentially as the distance from each fruiting body increased. More than 95% of the spores dropped within a meter from the fruiting body, with 75% dropping within 0.5 m. Even so, the number of spores dispersed over 5 m from the fruiting body was more than 50 million when considering the total number of spores produced by a fruiting body is about 5 billion.