• 제목/요약/키워드: Mean lifetime

검색결과 173건 처리시간 0.028초

Comparative Dynamics of $tRNA^{val}$ and pBluescript II SK(+) Phagemid Studied with Ethidium Bromide and a Long-lifetime Metal-ligand Complex

  • Kang, Jung-Sook;Yoon, Ji-Hye
    • Journal of Photoscience
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    • 제11권3호
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    • pp.133-139
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    • 2004
  • The metal-ligand complex, $[Ru(phen)_2(dppz)]^{2+}$ (phen=1,10-phenanthroline, dppz=dipyrido[3,2-a:2',3'-c]phenazine) (RuPD), was used as a spectroscopic probe for studying nucleic acid dynamics. The RuPD complex displays a long lifetime and a molecular light switch property upon DNA binding due to shielding of its dppz ligand from water. To show the usefulness of this luminophore (RuPD) for probing nucleic acid dynamics, we compared its intensity and anisotropy decays when intercalated into the $tRNA^{val}$ and pBluescript (pBS) II SK(+) phagemid through a comparison with ethidium bromide (EB), a conventional nucleic acid probe. We used frequency-domain fluorometry with a blue light-emitting diode (LED) as the modulated light source. The mean lifetime for the $tRNA^{val}$ (<${\tau}$> = 166.5 ns) was much shorter than that for the pBS II SK(+) phagemid (<${\tau}$> = 481.3 ns), suggesting a much more efficient shielding from water by the phagemid. Because of their size difference, the anisotropy decay data showed a much shorter rotational correlation times for the $tRNA^{val}$ (99.9 and 23.6 ns) than for the pBS II SK(+) phagemid (968.7 and 39.5 ns). These results indicate that RuPD can be useful for studying nucleic acid dynamics.

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희토류 원소 첨가 비정질 찰코지나이드 : 형광 수명과 유리 구조 변화의 관계 (Amorphous Chalcogenide Solids Doped with Rare-Earth Element : Fluorescence Lifetimes and the Glass Structural Changes)

  • 최용규
    • 한국세라믹학회지
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    • 제41권9호
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    • pp.696-702
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    • 2004
  • 찰코지나이드 유리에 첨가된 희토류 원소의 4f 전자 궤도를 구성하는 여기 상태 에너지 준위의 수명은 기지 재료의 단거리 구조 변화뿐만 아니라 중거리 구조 변화에도 매우 민감하다 Pr$^{3+}$ 이온을 첨가한 다양한 조성의 Ge-Sb-Se 계열 찰코지나이드 샘플을 대상으로 Pr$^{3+}$ ($^3$F$_3$, $^3$F$_4$)\$\longrightarrow$$^3$H$_4$천이로부터 발생하는 1.6$\mu\textrm{m}$ 형광의 수명을 측정한 결과, 해당 형광 수명은 mean coordination number가 -2.67이 되는 조성에서 최대 값을 나타내었다. 이는 유리의 구조가 2차원 구조에서 3차원 구조로 전환됨에 따라 희토류 이온의 분포도가 변화하기 때문이며 소위 topological structure 모델과 chemically ordered network모델로써 공유 결합성이 강한 찰코지나이드 유리에 첨가된 희토류 이온의 발광 특성에 대한 해석이 가능하였다. 이러한 결과는 희토류 원소의 분포 및 형광 수명을 단지 찰코지나이드 재료의 성분비만으로 예측할 수 있다는 새로운 관점이 타당함을 의미한다

NHPCI 지표를 활용한 공용성 추정과 수명 산정 (Estimation of Performance and Pavement Life using National Highway Pavement Condition Index)

  • 도명식;이용준;임광수;권수안
    • 한국도로학회논문집
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    • 제14권5호
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    • pp.11-19
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    • 2012
  • PURPOSES: The new methodology is proposed for estimation of long-term performance and pavement life based on the national highway database in Daejeon area. Furthermore, this study tried to verify the applicability of performance estimation using NHPCI (National Highway Pavement Condition Index) on tendency of pavement deterioration as time goes by under Korean road environments. METHODS: Reliability theories are applied to estimate the mean life and to determine the appropriate distribution using 3 levels of traffic loads (high, medium, low) based on maintenance and rehabilitation history data for 15 years. RESULTS: As a result, Lognormal distribution is suitable for explanation of pavement lifetime in Daejeon area regardless of traffic loads. In addition, we found that the results of mean life and maintenance timing based on NHPCI for the pavement sections of 3 levels of traffic loads are available. CONCLUSIONS: Based on this study, it was found that mean life of high, medium and low levels of traffic loads are about 8.1 years, 12.2 years and 12.7 years, respectively. Higher level of traffic loads shorten the pavement mean life.

코히어런트 시스템에서 평균잔여수명함수(平均殘餘壽命函數)의 추정(推定) (Estimation of Mean Residual Life Function for a Coherent System)

  • 박병구
    • Journal of the Korean Data and Information Science Society
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    • 제4권
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    • pp.97-107
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    • 1993
  • In this paper we propose a nonparametric estimator of the men residual life function (MRLF) on a coherent system under the condition that the component lifetimes are censored by system lifetime. It is shown that the proposed estimator, considered as a function of age t, converges weakly to a Gaussian process on a fixed interval. A consistent estimator of asymptotic variance of the proposed estimator is also given.

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교량 충격하중의 확률론적 모델 (Reliability-Based Dynamic Load Model for Bridges)

  • 황의승
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1991년도 가을 학술발표회 논문집
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    • pp.69-72
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    • 1991
  • The purpose of this study is to develop the reliability-based dynamic load model for bridges. Analytial procedure to calculate the dynamic load is developed. Truck traffic is simulated using Monte Carlo method. Static and dynamic loads(deflections) are plotted on the normal probability paper to estimate the mean maximum dynamic load in bridge lifetime. The results may be served as a basis for new LRFD bridge design code.

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EMPIRICAL BAYES TESTING FOR MEAN LIFE TIME OF RAYLEIGH DISTRIBUTION

  • Liang, TaChen
    • Journal of applied mathematics & informatics
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    • 제25권1_2호
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    • pp.1-15
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    • 2007
  • Consider a Rayleigh distribution with $$pdf\;p(x/{\theta})\;=\;2x{\theta}^{-1}\;{\exp}\;({-x^2}/{\theta})$$ and mean lifetime ${\mu}\;=\;\sqrt{\pi\theta}/2$. We study the two-action problem of testing the hypotheses $H_{0}\;:\;{\mu}{\leq}{\mu}_{0}$ against $H_{1}\;:\;{\mu}\;>\;{\mu}_{0}$ using a linear error loss of ${\mid}{\mu}\;-\;{\mu}_{0}{\mid}$ via the empirical Bayes approach. We construct a monotone empirical Bayes test ${\delta}^{*}_{n}$ and study its associated asymptotic optimality. It is shown that the regret of ${\delta}^{*}_{n}$ converges to zero at a rate $\frac{{\ln}^{2}n}{n}$, where n is the number of past data available when the present testing problem is considered.

지수고장분포(指數故障分布) 및 단속검사하(斷續檢査下)의 최적(最適) 가속수명시험(加速壽命侍險)의 설계(設計) (Design of Optimal Accelerated Life Tests for the Exponential Failure Distribution under Intermittent Inspection)

  • 서순근;최종덕
    • 대한산업공학회지
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    • 제17권1호
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    • pp.95-108
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    • 1991
  • For the case where the lifetime at a constant stress level has exponential distribution, optimal accelerated life test plans are developed under the assumptions of intermittent inspection and Type I censoring. In a optimal plan, the low and high stress levels, the proportion of test units allocated and the inspection times at each stress are determined such that the asymptotic variance of the maximum likelihood estimator of logarithmic transformed mean at the use condition is minimized. In addition to the optimal plan in which numerical technique to solve the set of nonlinear equations must be employed to determine inspection times at each stress level, we also propose another plans which employ equally-spaced or equal probability inspection schemes at two overstress levels of corresponding optimal one. For both optimal and proposed plans, computational results indicate that the asymptotic variance of the estimated mean at the use stress is insensitive to number of inspections at overstress levels for the range of parameter values considered.

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THE SOJOURN TIME AND RELATED CHARACTERISTICS OF THE AGE-DEPENDENT BRANCHING PROCESS

  • Kumar, B.-Krishba;Vijayakumar, A.
    • Journal of applied mathematics & informatics
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    • 제14권1_2호
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    • pp.157-172
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    • 2004
  • An age-dependent branching process where disasters occur as a renewal process leading to annihilation or survival of all the cells, is considered. For such a process, the total mean sojourn time of all the cells in the system is analysed using the regeneration point technique. The mean number of cells which die in time t and its asymptotic behaviour are discussed. When the disasters arrival as a Poisson process and the lifetime of the cells follows exponential distribution, elegant inter- relationships are found among the means of (i) the total number of cells which die in time t (ii) the total sojourn time of all cells in the system upto time t and (iii) the number of living cells at time t. Some of the existing results are deduced as special cases for related processes.

HeMOSU-1호 관측풍속의 불확실성을 고려한 서남해안의 풍력 발전량 예측 (Prediction of Wind Power Generation at Southwest Coast of Korea Considering Uncertainty of HeMOSU-1 Wind Speed Data)

  • 이기남;김동현;권오순
    • 신재생에너지
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    • 제10권2호
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    • pp.19-28
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    • 2014
  • Wind power generation of 5 MW wind turbine was predicted by using wind measurement data from HeMOSU-1 which is at south west coast of Korea. Time histories of turbulent wind was generated from 10-min mean wind speed and then they were used as input to Bladed to estimated electric power. Those estimated powers are used in both polynominal regression and neural network training. They were compared with each other for daily production and yearly production. Effect of mean wind speed and turbulence intensity were quantitatively analyzed and discussed. This technique further can be used to assess lifetime power of wind turbine.

미세변동공정관리를 위한 가속수명시험관리도 설계 (Design of ALT Control Chart for Small Process Variation)

  • 김종걸;엄상준
    • 대한안전경영과학회지
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    • 제14권3호
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    • pp.167-174
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    • 2012
  • In the manufacturing process the most widely used $\bar{X}$ chart has been applied to control the process mean. Also, Accelerated Life Test(ALT) is commonly used for efficient assurance of product life in development phases, which can be applied in production reliability acceptance test. When life data has lognormal distribution, through censored ALT design so that censored ALT data has asymptotic normal distribution, $ALT\bar{X}$ control chart integrating $\bar{X}$ chart and ALT procedure could be applied to control the mean of process in the manufacturing process. In the situation that process variation is controlled, $Z_p$ control chart is an effective method for the very small fraction nonconforming of quality characteristic. A simultaneous control scheme with $ALT\bar{X}$ control chart and $Z_p$ control chart is designed for the very small fraction nonconforming of product lifetime.