• Title/Summary/Keyword: dutch light type

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Development of Structural Model and Analysis of Design Factors for Small Greenhouse of Urban Agriculture (도시농업을 위한 소형온실 설계요인 분석 및 구조모델 개발)

  • Kim, Hyung-Kweon;Ryou, Young-Sun;Kim, Young-Hwa;Lee, Tae-Seok;Oh, Sung-Sik;Lee, Won-Suk;Kim, Yong-Hyeon
    • Journal of Bio-Environment Control
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    • v.28 no.4
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    • pp.388-395
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    • 2019
  • The purpose of this study is to suggest structural model and analyze design factors for the development of small greenhouse standardization model. The average dimensions of small greenhouse desired by urban farmers were 3.3m in width, 1.9m in eaves height, 2.7m in ridge height, 5.7m in length. The cladding materials for small greenhouse were preferred to glass, PC board and plastic film, framework to aluminum alloy and steel, and heating method in electrical energy. In addition, it was analyzed that small greenhouses need to develop structural model by dividing them into entry-level type and high-level type. The roof type that was used for entry-level type was arch shape, framework was steel pipe, cladding material was plastic film. On the other hand, high-level type was used in even span or dutch light type, framework with square hollow steel, cladding materials with glass or PC board. In consideration of these findings and practicality, this study developed four types of small greenhouses. The width, eaves height, ridges height, and length of the small greenhouses of even span type, which were covered with 5mm thick glass and 6mm thick PC board were 3m, 2.2m, 2.9m, and 6m, respectively. The small greenhouse of dutch light type covered with 5mm thick glass was designed with 3.8m in with, 2.2m in eaves height, 2.9m in ridges height, and 6m in length. The width, eaves height, ridges height, and length of the arch shape small greenhouse covered with a 0.15mm PO film were 3m, 1.5m, 2.8m, and 6m, respectively.

Variable structure control with a PI-type reaching law (PI 타입 도달 법칙을 가지는 가변구조 제어)

  • 금길수;전경한;최봉열
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.387-390
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    • 1996
  • In this paper, A new PI-type reaching law for variable structure control is proposed to alleviate the chattering and improve the robustness properties in the presence of matched uncertainty. The proposed reaching law consists of a proportional term and an integral term. And the dynamics of switching function can easily be specified by using the second-order system analysis method. And also the proposed scheme has the advantages of alleviating the chattering than Gao's one and reducing the influence of uncertainties by band pass filter characteristic. The efficiency of the proposed method has been demonstrated by simulations for Dutch Roll damping in a light aircraft.

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