• Journal of Bio-Environment Control
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• v.6 no.3
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• pp.133-142
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• 1997

Most of the greenhouses employ the roll-up type ventilation control system. Torque required to roll-up and down might be theoretically expressed with the weight times radius of the ventilation roll; however, measured torques were two times of the theoretically estimated values. As the window film of roll-up vent is used over the periods of time, the warping and crumpling of the material caused the increase of the torque in addition to a span deformation. Therefore, this study was performed to develop an empirical torque formulae to present basic torque data and to assist the development of roll-up type ventilation control system. The empirically adjusted rolling radius (r＋a) exponentially increased at the maximum span deformation. The coefficient of rolling resistance (Cr) was about 0.7―0.8 depending upon the wrinkle status of film material.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.336-341
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• 1995

종래의 Cam 구동방식 Pirn Winder에서는 낮은 권취속도와 만권시 권취 Bobbin이 Cradle에서 이탈될 때 권취 Yarn의 대량손실, Pirn 형성시 사층의 붕괴에 따른 과다권취등 기술적 난제가 대두되었다. 이러한 문제점을 해결하기 위하여 구미선진국에서는 Micom 제어 Pirn Winder가 개발되었다. 국내에서는 이 기계를 전량 수입에 의존하고 있어 수입 대체가 시급하지만 선진국의 기술보호주의 때문에 기술도입도 어려운 실정이다. 본 논문에서는 Micom제어 Pirn Winder에서 기본적으로 사층이 무너지지않기 위한 권취량, Traverse속도, 사속(Yarn Speed), 스핀들의 각속도 등을 결정함으로써 기구 학적 제어를 할 수 있는 알고리즘을 제시하고 컴퓨터 모사실험을 통하여 타당성을 보였다.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.145-149
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• 2003

벨벳 직물은 일반적인 직물과 달리 원단에 응모가 있어 보관 및 운반에 있어 각별한 주의가 요구되며 응모가 눌려지면 제품의 상품성이 상실되기 때문에 직물 표면의 형태를 유지하는 것이 매우 중요하다. 따라서 권취공정은 많은 주의가 요구되는 공정이다. 그러나 국내 벨벳 권취 업체들은 대부분 영세한 소규모 업체이고 전적으로 수 작업에 의해 작업을 진행하고있기 때문에 작업능률 저하 및 높은 불량률은 피할 수 없는 결과이다. (중략)

• Proceedings of the Korean Fiber Society Conference
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• 1999.04a
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• pp.167-172
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• 1999

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.5
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• pp.409-414
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• 2017

In the thin strip coiling process, it is necessary to use a sleeve with a mandrel to prevent excessive deformation of the strip. The stress distribution in the sleeve and strip is an important factor to determine the size of the sleeve. However, an experimental approach is almost impossible because of the accumulation of high pressure. A finite element (FE) model of the strip coiling process was developed in this study. Then, the radial and hoop stresses on the sleeve and strip were investigated using FE analyses. The theoretical values and analysis results under idealized conditions were compared to verify the FE model. The effect of the strip thickness on the stress distribution was also investigated. The radial stress increased by 6.3 times for a 1-mm-thick strip at the coil starting point. The radial stress at the sleeve increased by 14.8 % with a stacked thickness of 90 mm because of the reaction force applied by the mandrel.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.5906-5913
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• 2015

This paper analyzes the effect of adoption and complementarity of production technology bundles in horticultural greenhouse - more than 10m vinyl greenhouse ($T_1$), polyolefin film ($T_2$), winding branch ventilation ($T_3$), and more than 15 ounce lagging cover ($T_4$). The results are as follows: First, only using $T_1$, only using $T_2$, only using $T_3$, only using $T_4$, using $T_1$ and $T_3$, and using $T_1$ and $T_4$, have a higher net return. Second, when $T_3$ is used, $T_1$ and $T_2$ are complementary. Third, $T_1$ and $T_3$ are always complementary. Fourth, when $T_2$ and $T_3$ are not used, $T_1$ and $T_4$ are complementary. The results of this paper could contribute to government's technology diffusion policies and subsequent studies.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.2
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• pp.45-52
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• 1998

The contact roll is often used to regulate the winding tension as well as the entrained air in a wound roll by adjusting the contact force to the winding roll. But the contact force generated by other rolls, like assistant nip rolls, in a winding(or roll changing) process may act as disturbance to the control of the winding tension. In this paper, the mechanism of a roll change process is analysed. Ana, the behavior of the contact and the nip rolls are mathematically modeled. A nonlinear PID(NPID) controller is designed to control the winding tension and to reject the effect of disturbance generated by the nip roll on the winding tension variation. Computer simulation study showed that the performance of the suggested NPID controller is improved compared with that of the PID controller in controlling the winding tension and in rejecting the effect of the disturbance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.413-418
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• 1996

Alternate pirn winding is more difficult to control than others because starting points of its traverse strokes are changed alternately through the winding operations. However, the alternate pirn winding is ye useful method because the yarn can be hardly broken when it is unwinded from full packaged bobbin. This paper presents kinematic control algorithm for the alternate pirn. The proposed algorithm can decide the values of control variables such as bobbin speed and traverse speed from the given input parameters and constraints by using the kinematic relations of the winding mechanism. The compute simulations and experimental verifications of the developed winding control algorithm are carried out It is concluded that the proposed algorithm is an efficient and reliable alternative to traditional trial and error control methods.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.748-753
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• 1996

The contact roll is often used to regulate the winding tension as well as the entrained air in a wound roli by adjusting the contact force to the winding roll. But the contact force generated by other rolls, like assistant nip rolls, in a winding(or roll changing) process may act as disturbance to the control of the winding tension. In this paper, the mechanism of a roll change process is analyzed. And, the behavior of the contact and the assistant nip rolls are mathematically modeled. A nonlinear PID(NPID) controller is designed to control the winding tension and to reject the effect of disturbance generated by the assistant nip roll on the winding tension variation. Computer simulation study showed that the performance of the suggested NPID controller is improved compared with that of the PID controller in con trolling the winding tension and in rejecting the effect of the disturbance.

• The monthly packaging world
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• s.100
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• pp.158-161
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• 2001