• Title/Summary/Keyword: Formulae

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Estimation of the Unmeasured Unbalance Responses and Identification of Bearing Parameters in Flexible Rotor-Bearing Systems (회전체 베어링계의 불균형응답 간접추정과 베어링 매개변수 규명)

  • 홍성욱;이종원
    • Journal of KSNVE
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    • v.2 no.3
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    • pp.193-202
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    • 1992
  • The unbalance response analysis is one of the essential area in the forced vibration analysis of rotor bearing systems because of it usefulness in balancing and diagnosis as well as identification of parameters involved in rotor bearing systems. However some unbalance responses are not measurable due to the fact that rotor bearing systems are often encapsulated by fixtures or safety protectors. In the present paper, an efficent estimation scheme for unmeasured unbalance responses in rotor bearing systems is developed. The fundamental fearture of the proposed method is characterized by the linear formulae to estimate the unbalance responses from the measured unbalance responses and the finite element auxilliary model equation which is constructed to be identical to the prototype excluding the uncertain parameters such as bearing coefficients. The identification formulae for bearing parameters are also derived by using the unbalance response and the finite elements auxiliary model. Simulation is provided to verify the effectiveness of the proposed method.

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A Study on Stress Analysis and Fatigue Behaviors of Carbonitrided Cr-Mo(SCM415) Steel - About the Prediction of Fatigue Strength - (침탄질화 처리된 크롬-몰리브덴(SCM415)강의 피로거동 및 응력해석 (2) -피로강도의 예측을 중심으로-)

  • 송삼홍;이상훈
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.5
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    • pp.160-167
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    • 2000
  • In this research, the fatigue behaviors of carbonitrided Cr-Mo(SCM415) steel are examined. From fatigue test results, we propose a modified fatigue strength evaluation model and modified formulae. That is, we develop improved models fur evaluating and predicting the fatigue strength of carbonitrided SCM415 by modifying specific terms in the Murakami and Endo's model which is the representative fatigue strength evaluation formulae fur high strength steel.

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A Research on the Approximate Formulae for the Speed Loss at Sea (해상에서의 선속 손실량 산정을 위한 약산식 개발 연구)

  • KWON YOUNG-JOONG;KIM DAI YOUNG
    • Journal of Ocean Engineering and Technology
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    • v.19 no.2 s.63
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    • pp.90-93
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    • 2005
  • An improved approximate formula is presented for Series 60 forms, modifying the approximate formula, developed by the Author in 1983. The weather formula is based on interpretations of detailed calculations of speed loss, due to wind(van Berlekom), motions(Maruo), and wave reflection resistance(Kwon). Comparison is made between the result of the approximate formula and the one of detailed calculation. The result of the formula is also compared with some published full-scale data for speed loss.

Effect of Bojungikgitang on Starvation Stress in Mice (보중익기탕(補中益氣湯)이 생쥐의 기아(飢餓)stress에 미치는 영향)

  • Kim, Jung-Hoon;Lee, Tae-Hee
    • Herbal Formula Science
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    • v.14 no.1
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    • pp.133-140
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    • 2006
  • Objectives: We investigated the effect of Bojungikgitang on the change of the corticosterone and the rectal temperature of the mice induced by starvation stress. Methods: After administration of Bojungikgitang three times, mice were starved. The corticosterone and rectal temperature were measured after 36.5 hours starvation stress. Results : The plasma corticosterone level in Bojungikgitang(0.25g/Kg) was decreased comparing with the Control group and the rectal temperature in the Bojungikgitang(1.0g/Kg) was increased comparing with the Control group. Conclusion : it might be recognized that Bojungikgitang has anti starvation stress effect, and also it might be needed further study in various viewpoints.

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INTEGRATION WITH RESPECT TO ANALOGUE OF WIENER MEASURE OVER PATHS IN WIENER SPACE AND ITS APPLICATIONS

  • Ryu, Kun-Sik
    • Bulletin of the Korean Mathematical Society
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    • v.47 no.1
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    • pp.131-149
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    • 2010
  • In 1992, the author introduced the definition and the properties of Wiener measure over paths in Wiener space and this measure was investigated extensively by some mathematicians. In 2002, the author and Dr. Im presented an article for analogue of Wiener measure and its applications which is the generalized theory of Wiener measure theory. In this note, we will derive the analogue of Wiener measure over paths in Wiener space and establish two integration formulae, one is similar to the Wiener integration formula and another is similar to simple formula for conditional Wiener integral. Furthermore, we will give some examples for our formulae.

ZETA FUNCTIONS OF GRAPH BUNDLES

  • Feng, Rongquan;Kwak, Jin-Ho
    • Journal of the Korean Mathematical Society
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    • v.43 no.6
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    • pp.1269-1287
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    • 2006
  • As a continuation of computing the zeta function of a regular covering graph by Mizuno and Sato in [9], we derive in this paper computational formulae for the zeta functions of a graph bundle and of any (regular or irregular) covering of a graph. If the voltages to derive them lie in an abelian or dihedral group and its fibre is a regular graph, those formulae can be simplified. As a by-product, the zeta function of the cartesian product of a graph and a regular graph is obtained. The same work is also done for a discrete torus and for a discrete Klein bottle.

Vibration Analysis of Expansion Joint with Rotary Inertia Using Transfer Matrix Method (전달행렬법을 이용하여 회전관성을 고려한 Expansion Joint의 진동해석)

  • Shin, Dong-Ho;Oh, Jae-Eung;Lee, Jung-Youn
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.04a
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    • pp.544-549
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    • 2011
  • Simplified formulae for axial and bending natural frequencies of bellows are developed using an equivalent thin-walled pipe model. The axial and bending stiffness of bellows is determined using lumped transfer matrix method. Accordingly, the Expansion Joint Manufacturers Association (EJMA) formula for axial and bending stiffness calculation is modified using two different equivalent radii. The results from the simplified formulae are verified by those from a experiment result and a finite element (FE) model and good agreement is shown between the each other.

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A Study of Short Term Forecasting of Daily Water Demand Using SSA (SSA를 이용한 일 단위 물수요량 단기 예측에 관한 연구)

  • Kwon, Hyun-Han;Moon, Young-Il
    • Journal of Korean Society of Water and Wastewater
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    • v.18 no.6
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    • pp.758-769
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    • 2004
  • The trends and seasonalities of most time series have a large variability. The result of the Singular Spectrum Analysis(SSA) processing is a decomposition of the time series into several components, which can often be identified as trends, seasonalities and other oscillatory series, or noise components. Generally, forecasting by the SSA method should be applied to time series governed (may be approximately) by linear recurrent formulae(LRF). This study examined forecasting ability of SSA-LRF model. These methods are applied to daily water demand data. These models indicate that most cases have good ability of forecasting to some extent by considering statistical and visual assessment, in particular forecasting validity shows good results during 15 days.

Effects of Lycii Radicis Cortex in HPA-Axis System on the Forced Swimming Test (지골피(地骨皮)가 강제수영부하실험에서 HPA-Axis System에 미치는 영향)

  • Koo, Beom-Mo;Lee, Tae-Hee
    • Herbal Formula Science
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    • v.18 no.2
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    • pp.215-225
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    • 2010
  • In order to investigate the antidepressant effects of Lycii Radicis Cortex on the change of HPA-Axis system, the forced swimming test was performed. The expressions of CRF and c-Fos in the PVN were measured with immunohistochemical method and the concentration of ACTH in Serum was evaluated with ELISA method. And the results obtained were as follows. Results : 1. The duration of immobility in the forced swimming test was significantly decreased in the LRC100 group and the LRC400 group(P<0.001). 2. The expressions of CRF and c-Fos were significantly reduced in the LRC100 group and the LRC400 group(P<0.001). And the concentration of ACTH in Serum were significantly reduced in the LRC 100 group(P<0.05). According to the results above mentioned, it can be considered that Lycii Radicis Cortex has antidepressant effects.

General Theory of Wave Scattering by Two Separated Particles

  • Park, Byong Chon;Kim, Myung-Whun;Kim, Jin Seung
    • Journal of the Optical Society of Korea
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    • v.18 no.2
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    • pp.188-193
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    • 2014
  • A general theory of scalar wave scattering by two separated particles is developed to give the coefficients of scattering and transmission in the form of recurrence formulae. Iterative applications of the formulae yield the coefficients in the form of power series of the coefficients obtained from single-particle scattering theories, and each term of the of power series can be interpreted as multiple scattering of the wave between the two particles in increasingly higher order.