• Title/Summary/Keyword: isolation systems

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Reports on the Meetings of ISO/TC108 Mechanical Vibration and Shock and ISO/TC108/SC3 Use and Calibration of Shock Measuring Instruments Tokyo, Nov. 4-8, 2002

  • Kim, Kwang-Joon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.468-474
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    • 2003
  • 1. Schedule for the meetings of ISO/TC108 Mechanical vibration and shock and ISO/TC108/SC3 Use and calibration of shock measuring instruments 2. Minutes for the seventh meeting of ISO/TC108/WG23 Mechanical vibration and shock - Resilient mounting systems - Information for the application of source and receiver isolation (omitted)

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Design Methodology of the Korean High Speed Train (한국 고유형 고속전철 디자인 방법론)

  • 이병종;정경렬
    • Proceedings of the KSR Conference
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    • 2002.05a
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    • pp.344-350
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    • 2002
  • This paper proposes the Systematic Design Methodology of the Korean High Speed Train. High Speed Train do not operate in isolation and are part of a rail system which is influenced through input and output effects from the environment and from the neighbouring system. To fulfil its overall desired function, such input and output relationships between the systems must be considered in the system boundary conditions. Therefore, the overall interrelationship of all these effects has to be carefully considered during the design process. Here proposed methodology may provide a guide line and criteria for the systematic problem solving method of that highly complex High Speed Train System.

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Evaluation of Vertical Vibration Performance of Tridimensional Hybrid Isolation System for Traffic Loads (교통하중에 대한 3차원 하이브리드 면진시스템의 수직 진동성능 평가)

  • Yonghun Lee;Sang-Hyun Lee;Moo-Won Hur
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.28 no.1
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    • pp.70-81
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    • 2024
  • In this study, Tridimensional Hybrid Isolation System(THIS) was proposed as a vibration isolator for traffic loads, combining vertical and horizontal isolation systems. Its efficacy in improving serviceability for vertical vibration was analytically evaluated. Firstly, for the analysis, the major vibration modes of the existing apartment were identified through eigenvalue analysis for the system and pulse response analysis for the bedroom slab using commercial structural analysis software. Subsequently, a 16-story model with horizontal, vertical and rotational degrees of freedom for each slab was numerically organized to represent the achieved modes. The dynamic analysis for the measured acceleration from an adjacent ground to high-speed railway was performed by state-space equations with the stiffness and damping ratio of THIS as variables. The result indicated that as the vertical period ratio increased, the threshold period ratio where the slab response started to be suppressed varied. Specifically, when the period ratio is greater than or equal to 5, the acceleration levels of all slabs decreased to approximately 70% or less compared to the non-isolated condition. On the other hand, it was ascertained that the influence of damping ratios on the response control of THIS is inconsequential in the analysis. Finally, the improvement in vertical vibration performance of THIS was evaluated according to design guidelines for floor vibration of AIJ, SCI and AISC. It was confirmed that, after the application of THIS, the residential performance criteria were met, whereas the non-isolated structure failed to satisfy them.

Piecewise exact solution for seismic mitigation analysis of bridges equipped with sliding-type isolators

  • Tsai, C.S.;Lin, Yung-Chang;Chen, Wen-Shin;Chiang, Tsu-Cheng;Chen, Bo-Jen
    • Structural Engineering and Mechanics
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    • v.35 no.2
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    • pp.205-215
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    • 2010
  • Recently, earthquake proof technology has been widely applied to both new and existing structures and bridges. The analysis of bridge systems equipped with structural control devices, which possess large degrees of freedom and nonlinear characteristics, is a result in time-consuming task. Therefore, a piecewise exact solution is proposed in this study to simplify the seismic mitigation analysis process for bridge systems equipped with sliding-type isolators. In this study, the simplified system having two degrees of freedom, to reasonably represent the large number of degrees of freedom of a bridge, and is modeled to obtain a piecewise exact solution for system responses during earthquakes. Simultaneously, we used the nonlinear finite element computer program to analyze the bridge responses and verify the accuracy of the proposed piecewise exact solution for bridge systems equipped with sliding-type isolators. The conclusions derived by comparing the results obtained from the piecewise exact solution and nonlinear finite element analysis reveal that the proposed solution not only simplifies the calculation process but also provides highly accurate seismic responses of isolated bridges under earthquakes.

A Leaf-Inhabiting Endophytic Bacterium, Rhodococcus sp. KB6, Enhances Sweet Potato Resistance to Black Rot Disease Caused by Ceratocystis fimbriata

  • Hong, Chi Eun;Jeong, Haeyoung;Jo, Sung Hee;Jeong, Jae Cheol;Kwon, Suk Yoon;An, Donghwan;Park, Jeong Mee
    • Journal of Microbiology and Biotechnology
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    • v.26 no.3
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    • pp.488-492
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    • 2016
  • Rhodococcus species have become increasingly important owing to their ability to degrade a wide range of toxic chemicals and produce bioactive compounds. Here, we report isolation of the Rhodococcus sp. KB6, which is a new leaf-inhabiting endophytic bacterium that suppresses black rot disease in sweet potato leaves. We determined the 7.0 Mb draft genome sequence of KB6 and have predicted 19 biosynthetic gene clusters for secondary metabolites, including heterobactins, which are a new class of siderophores. Notably, we showed the first internal colonization of host plants with Rhodococcus sp. KB6 and discuss its potential as a biocontrol agent for sustainable agriculture.

Improving Database System Performance by Applying NoSQL

  • Choi, Yong-Lak;Jeon, Woo-Seong;Yoon, Seok-Hwan
    • Journal of Information Processing Systems
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    • v.10 no.3
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    • pp.355-364
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    • 2014
  • Internet accessibility has been growing due to the diffusion of smartphones in today's society. Therefore, people can generate data anywhere and are confronted with the challenge that they should process a large amount of data. Since the appearance of relational database management system (RDBMS), most of the recent information systems are built by utilizing it. RDBMS uses foreign-keys to avoid data duplication. The transactions in the database use attributes, such as atomicity, consistency, isolation, durability (ACID), which ensures that data integrity and processing results are stably managed. The characteristic of RDBMS is that there is high data reliability. However, this results in performance degradation. Meanwhile, from among these information systems, some systems only require high-performance rather than high reliability. In this case, if we only consider performance, the use of NoSQL provides many advantages. It is possible to reduce the maintenance cost of the information system that continues to increase in the use of open source software based NoSQL. And has a huge advantage that is easy to use NoSQL. Therefore, in this study, we prove that the leverage of NoSQL will ensure high performance than RDBMS by applying NoSQL to database systems that implement RDBMS.

Drive Circuit of 4-Level Inverter for 42V Power System

  • Park, Yong-Won;Sul, Seung-Ki
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.11B no.3
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    • pp.112-118
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    • 2001
  • In the near future, the voltage of power system for passenger vehicle will be changed to 42V from existing 14V./ Because of increasing power and voltage ratings used in the vehicle the motor drive system has high switching dv/dt and it generates electromagnetic interference (EMI) To solve these problems multi-level inverter system may be used The feature of multi-level inverter is the output voltage to be synthesized from several levels of voltage Because of this feature high switching dv/dt and EMI can be reduced in the multi-level inverter system But as the number of level is increased manufacturing cost is getting expensive and system size is getting large. Because of these disadvantages the application of multi-level inverter has been restricted only to high power drives. The method to reduce manufacturing cost and system size is to integrate circuit of multi-level inverter into a few chips But isolated power supply and signal isolation circuit using transformer or opto-coupler for drive circuit are obstacles to implement the integrated circuit (IC) In this paper a drive circuit of 4-level inverter suitable for integration to hybrid or one chip is proposed In the proposed drive circuit DC link voltage is used directly as the power source of each gate drive circuit NPN transistors and PNP transistors are used to isolate to transfer the control signals. So the proposed drive circuit needs no transformers and opto-couplers for electrical isolation of drive circuit and is constructed only using components to be implemented on a silicon wafer With th e proposed drive circuit 4- level inverter system will be possible to be implemented through integrated circuit technology Using the proposed drive circuit 4- level inverter system is constructed and the validity and characteristics of the proposed drive circuit are proved through the experiments.

Comparison of Total RNA Isolation Methods for Analysis of Immune-Related microRNAs in Market Milks

  • Oh, Sangnam;Park, Mi Ri;Son, Seok Jun;Kim, Younghoon
    • Food Science of Animal Resources
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    • v.35 no.4
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    • pp.459-465
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    • 2015
  • Bovine milk provides essential nutrients, including immunologically important molecules, as the primary source of nutrition to newborns. Recent studies showed that RNAs from bovine milk contain immune-related microRNAs (miRNA) that regulate various immune systems. To evaluate the biological and immunological activity of miRNAs from milk products, isolation methods need to be established. Six methods for extracting total RNAs from bovine colostrums were adopted to evaluate the isolating efficiency and expression of miRNAs. Total RNA from milk was presented in formulation of small RNAs, rather than ribosomal RNAs. Column-combined phenol isolating methods showed high recovery of total RNAs, especially the commercial columns for biofluid samples, which demonstrated outstanding efficiency for recovering miRNAs. We also evaluated the quantity of five immune-related miRNAs (miR-93, miR-106a, miR-155, miR-181a, miR-451) in milk processed by temperature treatments including low temperature for long time (LTLT, 63℃ for 30 min)-, high temperature for short time (HTST, 75℃ for 15 s)-, and ultra heat treatment (UHT, 120-130℃ for 0.5-4 s). All targeted miRNAs had significantly reduced levels in processed milks compared to colostrum and raw mature milk. Interestingly, the amount of immune-related miRNAs from HTST milk was more resistant than those of LTLT and UHT milks. Our present study examined defined methods of RNA isolation and quantification of immune-specific miRNAs from small volumes of milk for use in further analysis.

An Analytical Study on the Shape Development of U-shaped Steel Damper for Seismic Isolation System (면진시스템용 U형 강재댐퍼의 형상 개발에 대한 해석적 연구)

  • Quan, Chun-Ri;Oh, Sang-Hoon;Lee, Sang-Ho
    • Journal of Korean Society of Steel Construction
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    • v.22 no.1
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    • pp.43-53
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    • 2010
  • Seismic isolation is one of the most widely implemented and accepted seismic protection systems to limit or avoid damages from unforeseeable earthquakes. As an energy absorption device, however, the supplemental lead itself tends to pollute the environment. Consequently, it is predicted that the use of lead would be controlled. Considering the pollution caused by lead, several researchers are interested in the viability of using steel in place of lead. In this study, first, based on the results of a non-linear finite element analysis, the excellent deformation capacity of a very tough steel damper was demonstrated by comparing it with that of the SS400 damper and determining the effects of main parameters (the aspect ratio, thickness, and width) on the deformation capacity. Second, an optimum shape and design equation for a U-shaped damper with an opening based on stress distribution was suggested.