• Title, Summary, Keyword: low-maintenance

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A Turnout without Movable Parts for Magnetically Levitated Vehicles with Hybrid Magnets

  • Kakinoki, Toshio;Yamaguchi, Hitoshi;Yoshinaga, Naoya;Mukai, Eiichi;Nishi, Hiroyuki
    • Journal of international Conference on Electrical Machines and Systems
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    • v.3 no.3
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    • pp.312-316
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    • 2014
  • This paper describes a turnout without movable parts for magnetically levitated vehicles with hybrid magnets, which have been studied by the authors in place of streetcars. Their low construction cost and low maintenance is key to their practical use. Magnetic levitation systems using forces of attraction can generate guidance force automatically, but the damping force against lateral motion is negligible. However, the lateral damping characteristic was improved by using divided iron type magnets and rails. Using this turnout without movable parts will facilitate smooth direction switching.

The Investigation of Faunal Habitat Based on Ecological Rostoration of Urban Streams in Ulsan (울산시 도심하천의 생태하천 복원사업에 따른 동물상 서식실태 조사 분석)

  • Cho, Hong Je;Kang, Ho Seon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.16 no.5
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    • pp.1-17
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    • 2013
  • We researched the fauna restoration of 5 urban streams in Ulsan established as ecological streams by improving water quality and river environment. The fauna inhabitation were compared according to the conditions of geometrical feature such as river width, low-water channel width, ect and water quality, water volumn, inland and forceland. The Mugeo cheon has clearly shown the fauna restoration effects resulting from supplying sustainable maintenance water and wastewater treatments. In the Yaksa cheon, on the other hand, the restoration effects were low due to the inflow of wastewater and sledges in some part of stream ever though the improvement of water quality. The Yeocheon cheon was found to have disadvantage on the ecological inhabitations due to supplying the maintenance water with highly concentrated salinity. The fauna restoration effect of the Meongjeong cheon was low due to the inflow of wastewater to the down stream. Therefore by supplying the maintenance water and improving the connection to the Taehwa river at the estuary, better restoration effects could be observed. In the Cheokgwa cheon, which is almost a natural river, the ecological integrity of the fauna population has been maintained quite well. It was concluded that the project to transform urban streams into ecological streams should focus on not only keeping water volume and quality but also maintaining favorable conditions for the migration and settlement of animal species close to the natural state.

Longitudinal Study of Child-Teacher Relationship and Peer Interactions Based on Latent Profile Analysis (유아-교사 관계의 잠재프로파일 집단이 유아의 또래 상호작용에 미치는 영향에 관한 종단 연구)

  • Yi, Ye Jin;Shin, Yoolim
    • Family and Environment Research
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    • v.54 no.3
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    • pp.321-332
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    • 2016
  • This study clarified the maintenance of relationship between children and teachers based on longitudinal data and explored the latent classes. It clarified the latent classes connection with the children's peer play interaction. The subjects of this study were 194 children (aged 3) who attended 11 different kindergartens and daycare centers. We collected data three times (once every 6 months) until they reached age 4. The results of this study were: first, closeness, conflict, and dependence of child-teacher relationship that showed a continuous short-term connection. Second, we classified the child-teacher relationship into three groups according to longitudinal data. Those groups were, 'low level maintenance group' which had the lowest conflict and dependence compared to the highest closeness with teacher, 'middle level maintenance group' which had the teacher relationship in the middle level of the sub element area, and 'high level maintenance group' which showed high conflict and dependence compared to low closeness with the teacher. Third, the group which maintains a longitudinal high conflict.dependence showed more interruption and disruption behavior than the group which maintained a low conflict and dependence. In conclusion, the child-teacher relationship seemed to be the steady characteristic because it showed the early formation of a stable relationship. It was possible to predict the child's peer interaction through an early child-teacher relationship. Teachers need to be educated by the kindergarten and daily care center because the early formation of a child-teacher relationship can be the foundation of child's later peer and teacher relationships.

An Analysis on the Maintenance Effect of the HVAC System with On-line Management Method (공조설비의 온라인 유지관리 효과 분석)

  • Kim, Yong-Ki;Lee, Tae-Won;Kang, Sung-Ju;Woo, Nam-Sub
    • Proceedings of the SAREK Conference
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    • pp.54-59
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    • 2008
  • The poor maintenance and management of HVAC systems finally lead to the shortening of the life expectancy and result in the increase of operating costs and energy consumptions due to low efficiencies. Also, it is essential to try to develop ways to adequately maintain and to use the building facilities efficiently in order to preserve earth environment and the limited resource. In this study, an analysis on the maintenance and management cost for HVAC systems was carried out with the capacity of equipment. Besides, the LCC(Life Cycle Cost) based analysis was carried out to verify the effect of the doing maintenance and management. As the results, the case of the good maintenance and management is able to save LCC to 11 % than the case of the poor method.

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A Study on the Application of Quality Management to Fire Door Construction (방화문 시공시 현장품질관리지침 적용에 관한 연구)

  • Choi, Dong-ho
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.90-91
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    • 2019
  • When the fire door is recently installed in the field, there are frequent cases where the fire door is manufactured with fire door having low quality or different structure compared to the performance that the fire door producer has confirmed in the performance test or the construction specification. Accordingly, on-site quality management and maintenance guideline for fire doors were presented. In this paper, we tried to explain the requirements for the construction of fire doors during the on-site quality management and maintenance guideline for fire doors presented in the study.

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Research directions for maintenance criteria in Slab Track (콘크리트궤도 유지보수기준 정립을 위한 연구방향)

  • Eom, Jong-Woo;Lee, Myung-Suk;Kwon, Jin-Soo;Kim, Soo-Jung
    • Proceedings of the KSR Conference
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    • pp.979-987
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    • 2011
  • The Ballast Track has been widely applied in traditionally due to low initial cost and abundant elastic property. But the disadvantages of Ballast track are; labor-intensive and costly maintenance, weak in high-speed and heavy axial load, in additionally need wide cross section of tunnel and massive substructure in viaduct. Therefore, recent applications tend to more and more towards slab track such as Gyeungbu high speed rail and existing line. The slab track increased the stability, resistance and durability of track, and save maintenance cost compare to the Ballast Track. But the slab track have weakness of track elongation by sub-ballast differential settlement and that threat safety of train operation. Therefor the slab track need to prevent cracks in concrete ballast for insure the durability of slab track. In this paper, review main items and its expected effects of the slab track maintenance standards that control sub-ballast settlement and concrete ballast cracks.

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Improving Overall Equipment Effectiveness(OEE) in Korean Small and Medium Manufacturing Industries (중소제조업체의 설비효율향상 방안에 대한 연구)

  • Baek, Jong-Yeop;Gang, Yun-Jin;Gang, Gyeong-Sik
    • Proceedings of the Safety Management and Science Conference
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    • pp.219-230
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    • 2010
  • Remarkably improvements have occurred recently in the maintenance management of physical assets and productive systems, so that less wastages of energy and resources occur. The technology of maintenance is about finding and applying cost-effective ways of avoiding or overcoming performance deterioration. Maintenance is thus a vital support function in business, especially as increasingly large investments are being required in physical assets. TPM(Total Productive Maintenance) focuses on optimizing planning scheduling. Availability, performance and quality rate are other factors that affect productivity. Especially there are some losses that affect the overall equipment effectiveness(OEE). These losses lead to low values of OEE, which provides an indication of how effective the production precess is. This study explores the ways in which Korean small and medium manufacturing industries can improve OEE.

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Maintenance Management System for School Buildings (학교시설물 유지관리 시스템 기능 제안)

  • Ahn, Sang-Hyun;Moon, Gi-Song;Yu, Jung-Ho;Kim, Chang-Duk
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • pp.545-548
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    • 2007
  • The 10,876 school buildings(year 2006) including elementary, junior high and high schools have been operated and the number of school buildings will increase with BTL(Build Transfer Lease) projects. However, as population is expected to decrease rapidly with low birth rate, it needs to pay more attention to managing existing school buildings. The present maintenance and management system is not being operating with regular plans but with making repairs when if problem happens. Therefore, in this study I will propose a new maintenance and management system which will improve the process of maintenance and management works and reflect the needs of related officials in charge of with analyzing a present maintenance and management system through making research into documents and questionnaires. It enables to simplify maintenance and management work, to manage budget with transparency and to make better communication between each work so that it promotes efficiency of maintenance and management work.

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Single Line-to-ground Fault Location and Information Modeling Based on the Interaction between Intelligent Distribution Equipment

  • Wang, Lei;Luo, Wei;Weng, Liangjie;Hu, Yongbo;Li, Bing
    • Journal of Electrical Engineering and Technology
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    • v.13 no.5
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    • pp.1807-1813
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    • 2018
  • In this paper, the fault line selection and location problems of single line-to-ground (SLG) fault in distribution network are addressed. Firstly, the adaptive filtering property for empirical mode decomposition is formulated. Then in view of the different characteristics showed by the intrinsic mode functions(IMF) under different fault inception angles obtained by empirical mode decomposition, the sign of peak value about the low-frequency IMF and the capacitance transient energy is chosen as the fault line selection criteria according to the different proportion occupied by the low-frequency components. Finally, the fault location is determined based upon the comparison result with adjacent fault passage indicators' (FPI) waveform on the strength of the interaction between the distribution terminal unit(DTU) and the FPI. Moreover, the logic nodes regarding to fault line selection and location are newly expanded according to IEC61850, which also provides reference to acquaint the DTU or FPI's function and monitoring. The simulation results validate the effectiveness of the proposed fault line selection and location methods.