• Title/Summary/Keyword: soundness

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Excess Vibration Phenomena and Soundness of Drain Piping in Moisture Separator Reheat Exchanger (습분 분리 재열기 배수배관의 과도진동과 배관 건전성)

  • Kim, Yeon-Whan;Kim, Hee-Soo;Bae, Yong-Chae;Lee, Hyun;Lee, Young-Shin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.393-398
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    • 2001
  • Pulsations, vibration and stress are the basic dynamic phenomena in power plant piping systems which directly affect system reliability. These phenomena are both acoustical and mechanical in nature and are closely interrelated. It was noticed that thermodynamic parameters were changed after replacing with new type tube bundles of reheat exchanger. It was reported later that the drain piping connecting the new bundle header with the associated drain tank is regularly pulsating at about every 3 second with 13.4㎐ and 7.5mm, p-p in amplitude. This amplitude is about 6 times higher than reference level of sound piping. The results of finite element analysis of the pipeline showed that its dominant natural frequency is 13.4㎐. The soundness is predicted whether the bending dynamic stress evaluated excesses the maximum allowable high cycle fatigue stress or not by the measured amplitude of vibration.

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Leakage Current Measurement and Management of Arresters Installed in Feeder Lines (급전선로에 설치되어 있는 피뢰기의 누설전류 측정과 관리방안)

  • Han Ju-Seop;Seo Hwang-Dong;Kil Gyung-Suk;Han Moon-Seob;Jang Dong-Uk
    • Proceedings of the KSR Conference
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    • 2005.05a
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    • pp.819-824
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    • 2005
  • This paper describes the measurement result of leakage current flowing arresters connected in feeder lines to propose an optimal management method. Twenty seven arresters set in seven areas were analyzed on a regular basis for 4 months. The results showed that the RMS and the peak value of the total leakage currents for soundness arresters were a range of $200uA{\sim}00uA$. respectively. During the period of measurement, the magnitude of the leakage current didn't show conspicious changes and there were impossible places to analyze arrester's status due to including high THD rate in a feeder line, From the study, leakage current measurement has to be performed at a condition without running an electric train in the line, and the allowable RMS value of soundness arrester is bellow 600uA.

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A Study on the Non-destructive Inspection for End Closure Welding of Nuclear Fuel Elements for the Irradiation Test (조사시험용 핵연료봉 용접부 비파괴검사에 관한 연구)

  • 김웅기;김수성;이철용;이도연;이정원
    • Proceedings of the KWS Conference
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    • 2004.05a
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    • pp.302-304
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    • 2004
  • Nuclear fuel elements containing dry recycling nuclear fuel pellets for the irradiation test in a reactor were remotely fabricated from spent PWR fuel materials in a hot cell. End closure welding as well as seal tube welding for thermal sensor of the elements was performed by Nd:YAG laser. The soundness of the end closure welds and seal tube welds for the elements were evaluated by a precise X-ray inspection system composed of a micro-focus X-ray generator with an image intensifier and a real time camera system. Then, helium leak test was performed for the elements. The soundness of the welds of the fuel elements was confirmed by the X-ray inspection and helium leak test. The irradiation test for the fuel elements were successfully completed at the HANARO research reactor.

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The Public-Private Partnerships and the Fiscal Soundness of Local Governments in Korea

  • LEE, HOJUN
    • KDI Journal of Economic Policy
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    • v.39 no.1
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    • pp.41-82
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    • 2017
  • This paper studies the risks associated with local finance in Korea by identifying the financial status of each local government, including the financial burdens of PPP projects, and examined governmental future burdens related to PPP projects. We reviewed all fiscal burdens associated with projects, such as, for BTL (Build-Transfer-Lease) types of projects, facility lease and operating expenses, and, for the BTO (Build-Transfer-Operate) types of projects, construction subsidies that are paid at the construction stage, MRG (Minimum Revenue Guarantee) payments and the government's share of payment. Furthermore, we compared the annual expenditures of local governments on PPP projects against their annual budgets and checked if the 2% ceiling rule could be applied.

The Sound and Complete Gentzen Deduction System for the Modalized Łukasiewicz Three-Valued Logic

  • Cao, Cungen;Sui, Yuefei
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.16 no.3
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    • pp.147-156
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    • 2016
  • A modalized Łukasiewicz three-valued propositional logic will be proposed in this paper which there are three modalities [t]; [m]; [f] to represent the three values t; m; f; respectively. And a Gentzen-typed deduction system will be given so that the the system is sound and complete with respect to the Łukasiewicz three-valued semantics Ł$_3$, which are given in soundness theorem and completeness theorem.

Resonance avoidance and Safety Evaluation of Vertical Pump (입형펌프의 공진회피와 안전성 평가)

  • Jeong, Wooyoung;Song, Jindae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.04a
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    • pp.698-702
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    • 2013
  • This paper considers the vertical pumps resonance and soundness. Normally large vertical pump's rotating speed is low, so the low natural mode can make a resonance on the motor and motor stand assembly. The pump resonance makes a very high vibration and trouble on the pump systems. Thus to avoid pump resonance when the pump is on the resonance region, we give the added mass method and evaluate the structure soundness by computer simulation and test on the site. Furthermore we evaluate the modal sensitivity and expect running conditions by the using ISO10814.

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A Study on the Deterioration Progress of Railway Arresters (철도용 피뢰기의 열화진전에 관한 연구)

  • 길경석;한주섭;한문섭
    • Journal of the Korean Society for Railway
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    • v.7 no.4
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    • pp.307-311
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    • 2004
  • Arresters are the best protective device on electrical power systems against transient overvoltages generated by lightning and/or switching operation. Nonetheless, arresters are deteriorated by absorption of moisture in the environments of its use, repetition in the protective operation to overvoltages, and some defects at manufacturing. It is therefore important to estimate the electrical characteristic changes of ZnO blocks. In this paper, an accelerated ageing test by a standard lightning impulse current was carried out to extract parameters needed for arrester diagnosis, and leakage current components were measured. Total energy applied to the ZnO blocks at each time is about 1,050[J] in 8/20[${\mu}\textrm{s}$] impulse current. From the experimental results, we proposed electrical parameters and leakage current level to diagnose arrester soundness.

Structual Design Verification and Design Optimization of Pantograph for Korean Very High Speed Train (한국형 고속전철용 판토그라프 구조설계 검증 및 설계 최적화)

  • 정경렬;김휘준;백진성;박수홍
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.1229-1234
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    • 2001
  • There are three items, which are panhead displacement, tilting angle of pan head, required moment of main shaft, which representing kinematic performance of pantograph. Kinematic variables effective on kinematic performance are length of each components and installation angle, In this study, cost function is defined with 3 items, By this cost function, length of thrust rod was optimized. Finite element analysis was used to consider structural soundness. Finite element model was qualified by comparison between analysis result with experiment result. By qualified F.E, model various severe condition was simulated to consider structural soundness.

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Computerization and Application of the Korean Standard Pronunciation Rules (한국어 표준발음법의 전산화 및 응용)

  • 이계영;임재걸
    • Language and Information
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    • v.7 no.2
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    • pp.81-101
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    • 2003
  • This paper introduces a computerized version of the Korean Standard Pronunciation Rules that can be used in speech engineering systems such as Korean speech synthesis and recognition systems. For this purpose, we build Petri net models for each item of the Standard Pronunciation Rules, and then integrate them into the sound conversion table. The reversion of the Korean Standard Pronunciation Rules regulates the way of matching sounds into grammatically correct written characters. This paper presents not only the sound conversion table but also the character conversion table obtained by reversely converting the sound conversion table. Malting use of these tables, we have implemented a Korean character into a sound system and a Korean sound into the character conversion system, and tested them with various data sets reflecting all the items of the Standard Pronunciation Rules to verify the soundness and completeness of our tables. The test results show that the tables improve the process speed in addition to the soundness and completeness.

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Closest Vector Problem Based Interactive Proof (Closest Vector Problem에 기반한 Interactive Proof)

  • Lee, Kyunghee;Nyang, DaeHun
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.22 no.6
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    • pp.1265-1270
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    • 2012
  • In this paper, we propose a new closest vector problem based interactive proof that is useful for authentication. Contribution of this paper is that the proposed protocol does not use a special form of a lattice, but a general lattice, which makes the protocol design very simple and easy to be proved. We prove its security in terms of completeness, soundness, simulatability.