• Title/Summary/Keyword: the exponential function

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Noninformative Priors for the Stress-Strength Reliability in the Generalized Exponential Distributions

  • Kang, Sang-Gil;Kim, Dal-Ho;Lee, Woo-Dong
    • Communications for Statistical Applications and Methods
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    • v.18 no.4
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    • pp.467-475
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    • 2011
  • This paper develops the noninformative priors for the stress-strength reliability from one parameter generalized exponential distributions. When this reliability is a parameter of interest, we develop the first, second order matching priors, reference priors in its order of importance in parameters and Jeffreys' prior. We reveal that these probability matching priors are not the alternative coverage probability matching prior or a highest posterior density matching prior, a cumulative distribution function matching prior. In addition, we reveal that the one-at-a-time reference prior and Jeffreys' prior are actually a second order matching prior. We show that the proposed reference prior matches the target coverage probabilities in a frequentist sense through a simulation study and a provided example.

Analysis and Optimization of Bidirectional Exponential SC Power Conversion Circuits

  • Ye, Yuanmao;Peng, Wei;Jiang, Bijia;Zhang, Xianyong
    • Journal of Power Electronics
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    • v.18 no.3
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    • pp.672-680
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    • 2018
  • A bidirectional exponential-gain switched-capacitor (SC) DC-DC converter is developed in this paper. When compared with existing exponential SC converters, the number of switches is significantly reduced and its structure is simplified. The voltage transfer features, voltage ripple across capacitors, efficiency and output impedance of the proposed converter are analyzed in detail. Optimization of the output impedance is also discussed and the best type of capacitance distribution is determined. A common function of the voltage gain to the output impedance is found among the proposed converter and other popular SC voltage multipliers. Experimental evaluation is carried out with a 6-24V bidirectional prototype converter.

Three Dimensional Thermal Cycle Analysis of Mold in Repeated Forming Process of TV Glass (TV 유리의 반복 성형공정에서 3차원 금형 열사이클 해석)

  • Hwang, Jung-Hea;Choi, Joo-Ho;Kim, Jun-Bum
    • Proceedings of the KSME Conference
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    • 2000.11b
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    • pp.192-198
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    • 2000
  • Three dimensional thermal cycle analysis of the plunger is carried out in repeated forming process of the TV glass, which is continued work of two dimensional analysis where an efficient method has been proposed. The plunger undergoes temperature fluctuation during a cycle due to the repeated contact and separation from the glass, which attains a cyclic steady state having same temperature history at every cycle. Straightforward analysis of this problem brings about more than 90 cycles to get reasonable solution. An exponential function fitting method is proposed, which finds exponential function to best approximate temperature values of 3 consecutive cycles, and new cycle is restarted with the fitted value at infinite time. Number of cases are analyzed using the proposed method and compared to the result of straightforward repetition, from which one finds that the method always reaches nearly convergent solution within $9{\sim}12$ cycles, but turns around afterwards without further convergence. Two step use is found most efficient, in which the exponential fitting is carried out fer the first 12 cycles, followed by simple repetition, which shows fast convergence expending only 6 additional cycles to get the accuracy within 2 error. This reduces the computation cycle remarkably from 90 to 18, which is 80% reduction. From the parametric studies, one reveals that the overall thermal behavior of the plunger in terms of cooling parameters and time is similar to that of 2 dimensional analysis.

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ON GLOBAL EXPONENTIAL STABILITY FOR CELLULAR NEURAL NETWORKS WITH TIME-VARYING DELAYS

  • Kwon, O.M.;Park, Ju-H.;Lee, S.M.
    • Journal of applied mathematics & informatics
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    • v.26 no.5_6
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    • pp.961-972
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    • 2008
  • In this paper, we consider the global exponential stability of cellular neural networks with time-varying delays. Based on the Lyapunov function method and convex optimization approach, a novel delay-dependent criterion of the system is derived in terms of LMI (linear matrix inequality). In order to solve effectively the LMI convex optimization problem, the interior point algorithm is utilized in this work. Two numerical examples are given to show the effectiveness of our results.

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Object Size Prediction based on Statistics Adaptive Linear Regression for Object Detection (객체 검출을 위한 통계치 적응적인 선형 회귀 기반 객체 크기 예측)

  • Kwon, Yonghye;Lee, Jongseok;Sim, Donggyu
    • Journal of Broadcast Engineering
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    • v.26 no.2
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    • pp.184-196
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    • 2021
  • This paper proposes statistics adaptive linear regression-based object size prediction method for object detection. YOLOv2 and YOLOv3, which are typical deep learning-based object detection algorithms, designed the last layer of a network using statistics adaptive exponential regression model to predict the size of objects. However, an exponential regression model can propagate a high derivative of a loss function into all parameters in a network because of the property of an exponential function. We propose statistics adaptive linear regression layer to ease the gradient exploding problem of the exponential regression model. The proposed statistics adaptive linear regression model is used in the last layer of the network to predict the size of objects with statistics estimated from training dataset. We newly designed the network based on the YOLOv3tiny and it shows the higher performance compared to YOLOv3 tiny on the UFPR-ALPR dataset.

다항지수 신뢰도 함수

  • Choi, Gyu-Sik
    • Proceedings of the Korea Society of Information Technology Applications Conference
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    • 2007.05a
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    • pp.103-108
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    • 2007
  • 다항지수 신뢰도 함수(multinomial-exponential reliability function ; MERF) 는 소프트웨어의 고장/수정 공정을 세밀하게 수행하는 중에 개발되는 관계에 있다. 후에 MERF는 좀더 매우 단순화한 지수 신뢰도 함수(exponential reliability function ; EARF)로 근사화되는 공정을 거치게 된다. 이는 MERF의 특성을 대부분 가지고 있어서 두 개의 함수가 하나의 신뢰도 함수로 단일화되도록 한다. 신뢰도 모델 MERF/EARF는 소프트웨어 고장 공정을 NHPP로, 수정공정을 다항분포로 고려한다. 이 모텔은 두 개의 공정 모두가 통계적 독립인 것으로 간주한다. 본 논문에서는 모델의 이론적인 기준, 수학적 특성, 소프트웨어 신뢰도에의 응용을 검토한다. 이는 물리적 인 시스템을 검사하고 유지보수하는 선도적인 모델응용이다. 본 논문에는 소프트웨어 신뢰도 분석에 응용하는 하나의 수치 예를 포함한다.

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DISTURBANCE ATTENUATION FOR A CLASS OF DISCRETE-TIME SWITCHED SYSTEMS WITH EXPONENTIAL UNCERTAINTY

  • Li, Changlin;Long, Fei;Ren, Guohui
    • Journal of the Korean Mathematical Society
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    • v.48 no.4
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    • pp.775-795
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    • 2011
  • The disturbance attenuation problem for a class of discretetime switched linear systems with exponential uncertainties via switched state feedback and switched dynamic output feedback is investigated, respectively. By using Taylor series approximation and convex polytope technique, exponentially uncertain discrete-time switched linear system is transformed into an equivalent switched polytopic model with additive norm bounded uncertainty. For such equivalent switched model, one designs its switching strategy and associated state feedback controllers and dynamic output feedback controllers so that whole switched model is asymptotical stabilization with H-in nity disturbance attenuation base on switched Lyapunov function and LMI approach. Finally, two numerical examples are presented to illustrate our results.

Applicability of exponential stress-strain models for carbonate rocks

  • Palchik, Vyacheslav
    • Geomechanics and Engineering
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    • v.15 no.3
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    • pp.919-925
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    • 2018
  • Stress-strain responses of weak-to-strong carbonate rocks used for tunnel construction were studied. The analysis of applicability of exponential stress-strain models based on Haldane's distribution function is presented. It is revealed that these exponential equations presented in transformed forms allow us to predict stress-strain relationships over the whole pre-failure strain range without mechanical testing of rock samples under compression using a press machine and to avoid measurements of axial failure strains for which relatively large values of compressive stress are required. In this study, only one point measurement (small strain at small stress) using indentation test and uniaxial compressive strength determined by a standard Schmidt hammer are considered as input parameters to predict stress-strain response from zero strain/zero stress up to failure. Observations show good predictive capabilities of transformed stress-stress models for weak-to-strong (${\sigma}_c$ <100 MPa) heterogeneous carbonate rocks exhibiting small (< 0.5 %), intermediate (< 1 %) and large (> 1 %) axial strains.