• Title/Summary/Keyword: 포그

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Development of CFD Model for Estimation of Cooling Effects of Fog Cooling System in Greenhouse (온실 포그냉방시스템의 냉방효과 예측을 위한 CFD 모델의 개발)

  • 유인호;김문기;권혁진
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 2001.11a
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    • pp.78-81
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    • 2001
  • 포그냉방시스템에 관한 연구는 대부분 VETH선도 등을 이용하여 온실 환경이 전체적으로 동질이라는 가정하에서 환기량 및 전체 분무수량 등을 계산하는 정도였으나, 1990년대 중반에 들어서면서 CFD 기법을 이용하여 온실 환경을 보다 정확하게 해석할 목적으로 CFD 기법을 이용하는 연구가 활발하게 이루어지고 있다. (중략)

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Hybrid Main Memory based Buffer Cache Scheme by Using Characteristics of Mobile Applications (모바일 애플리케이션의 특성을 이용한 하이브리드 메모리 기반 버퍼 캐시 정책)

  • Oh, Chansoo;Kang, Dong Hyun;Lee, Minho;Eom, Young Ik
    • Journal of KIISE
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    • v.42 no.11
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    • pp.1314-1321
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    • 2015
  • Mobile devices employ buffer cache mechanisms, just as in computer systems such as desktops or servers, to mitigate the performance gap between main memory and secondary storage. However, DRAM has a problem in that it accelerates battery consumption by performing refresh operations periodically to maintain the stored data. In this paper, we propose a novel buffer cache scheme to increase the battery lifecycle in mobile devices based on a hybrid main memory architecture consisting of DRAM and non-volatile PCM. We also suggest a new buffer cache policy that allocates buffers based on process states to optimize the performance and endurance of PCM. In particular, our algorithm allocates each page to the appropriate position corresponding to the state of the application that owns the page, and tries to ensure a rapid response of foreground applications even with a small amount of DRAM memory. The experimental results indicate that the proposed scheme reduces the elapsed time of foreground applications by 58% on average and power consumption by 23% on average without negatively impacting the performance of background applications.

Actual State of Practical Use and Cooling Effect of Evaporative Cooling Systems (증발냉각시스템의 활용실태 및 냉방효과)

  • 김문기;유인호;김기성
    • Journal of Bio-Environment Control
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    • v.8 no.4
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    • pp.281-287
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    • 1999
  • In order to take a good look at effectiveness of cooling of Fog system and Pad-Fan system, we chose 49 farm households which were installed evaporative cooling system and 2 farm households which were installed Pad-Fan system and Fog system for a test. We execute the test on 29 households out of 49.6 households, which were installed Pad-Fan system, were able to use; however, 6 household out of 9 which were installed Fog system couldn't use it. The main reason was the clogged on nozzle. The cooling efficiency on Pad-Fan system was 77.4%, but it was very poor on Fog system. Since there are many problems on Fog system, we need more research on size of fog, the location of nozzle, control of Fog systems.

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Control of Bemisia tabaci by Two-Fluid Fogging System (이류체 포그시스템을 활용한 가루이 방제)

  • Kim, Sung-Eun;Lee, Sang-Don;Sim, Sang-Youn;Kim, Young-Shik
    • Journal of Bio-Environment Control
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    • v.20 no.4
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    • pp.394-398
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    • 2011
  • The effect of two-fluid fogging system on the control of Bemisia tabaci in tomato cultivation was evaluated in a greenhouse. The number of Bemisia tabaci was decreased by 87% from the fog treatment for 7 days. During the fog treatment, the mean daily temperature was decreased by $2^{\circ}C$ and the mean daily relative humidity was increased by 3~4% as compared to the non-treatment. The reduction of Bemisia tabaci in the treatment might not be resulted from the differences in temperature and humidity in the greenhouse. The sound coming from the two-fluid fogging system did not affect when it was operated without water inside. Therefore it was concluded that water droplets coming out the nozzle reduced the growth and the movement of whiteflies because the suspension of tiny water droplets were attached on the skin of whiteflies.

Eco-friendly Control of Whiteflies by Two-Fluid Fogging System with Natural Substances in Greenhouses (이류체 포그시스템 및 천연물을 이용한 친환경적 가루이 방제)

  • Kim, Sung-Eun;Lee, Sang-Don;Lee, Moon-Haeng;Kim, Young-Shik
    • Journal of Bio-Environment Control
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    • v.21 no.2
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    • pp.114-119
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    • 2012
  • We have conducted 4 experiments to develop the most environmental and effective use of the two-fluid fog system to prevent and exterminate whiteflies in tomato cultivation. In particular, these experiments used Vitamini tomatoes grown in stand-alone greenhouses at Buyeo Tomato Experiment Station as subjects. Each experiment utilized the fog system in a different way. The first experiment provided the control group, which was subject to the two-fluid fog system without additional humidity control. In the second experiment, the two-fluid fog system controlled the humidity level to be above 70%. The third and the fourth experiment utilized natural substances, which were 1.5 mg/L of Neem Oil and 2 mg/L of Oleic acid respectively, without additional humidity control. From the first experiment, we could observe that a simple use of the two-fluid fog system decreased the density of whiteflies in the greenhouses. This impact of the fog system on whiteflies was greater in the second experiment. By comparing the first and the second experiment, we concluded that whiteflies are more effectively prevented by maintaining a higher humidity level via the fog system's smaller water droplets that float in the air for longer time than the standard fog system in rather dry condition. In the third and the fourth experiments, the extermination level was 78% and 76.4% respectively, comparing only 53% in the first experiment without the humidity control. Therefore, using the natural substances in addition to the humidity control increases the extermination effectiveness. Considering the similar results from the 3rd and the 4th experiments, Oleic acid has a greater appeal for its lower price. Using the two-fluid fog system to both control the humidity on a daily basis and spray the substances for occasional extermination would reduce labor cost and increase production in an environmental way.

Fine Dust Monitoring and Removal Method in Urban Construction Sites Using Autonomous Mobile Vehicle and Dry Fog System (자율이동체와 드라이포그를 활용한 도심지 건설현장 미세먼지 모니터링 및 대응 방안)

  • Kim, Kyoon Tai
    • Ecology and Resilient Infrastructure
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    • v.6 no.4
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    • pp.277-286
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    • 2019
  • The construction industry is known to be one of the representative industries that generate fine dust. Therefore, reducing the amount of fine dust generated in construction sites is very important for the overall fine dust management. Based on this, this study proposed the fine dust measurement and removal technology combined with advanced technologies such as autonomous mobile vehicle IoT and DFS. The qualitative, quantitative and risk elimination effects that can be expected when applying the proposed technique are analyzed. The proposed technique will be validated through system development and field application and evaluated specific economics through cost analysis.

A Resource Management Scheme Based on Live Migrations for Mobility Support in Edge-Based Fog Computing Environments (에지 기반 포그 컴퓨팅 환경에서 이동성 지원을 위한 라이브 마이그레이션 기반 자원 관리 기법)

  • Lim, JongBeom
    • KIPS Transactions on Software and Data Engineering
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    • v.11 no.4
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    • pp.163-168
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    • 2022
  • As cloud computing and the Internet of things are getting popular, the number of devices in the Internet of things computing environments is increasing. In addition, there exist various Internet-based applications, such as home automation and healthcare. In turn, existing studies explored the quality of service, such as downtime and reliability of tasks for Internet of things applications. To enhance the quality of service of Internet of things applications, cloud-fog computing (combining cloud computing and edge computing) can be used for offloading burdens from the central cloud server to edge servers. However, when devices inherit the mobility property, continuity and the quality of service of Internet of things applications can be reduced. In this paper, we propose a resource management scheme based on live migrations for mobility support in edge-based fog computing environments. The proposed resource management algorithm is based on the mobility direction and pace to predict the expected position, and migrates tasks to the target edge server. The performance results show that our proposed resource management algorithm improves the reliability of tasks and reduces downtime of services.