• Title/Summary/Keyword: random variation

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REGULAR VARIATION AND STABILITY OF RANDOM MEASURES

  • Quang, Nam Bui;Dang, Phuc Ho
    • Journal of the Korean Mathematical Society
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    • v.54 no.3
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    • pp.1049-1061
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    • 2017
  • The paper presents a characterization of stable random measures, giving a canonical form of their Laplace transform. Domain of attraction of stable random measures is concerned in a theorem showing that a random measure belongs to domain of attraction of any stable random measures if and only if it varies regularly at infinity.

Cost-Efficient and Automatic Large Volume Data Acquisition Method for On-Chip Random Process Variation Measurement

  • Lee, Sooeun;Han, Seungho;Lee, Ikho;Sim, Jae-Yoon;Park, Hong-June;Kim, Byungsub
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.15 no.2
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    • pp.184-193
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    • 2015
  • This paper proposes a cost-efficient and automatic method for large data acquisition from a test chip without expensive equipment to characterize random process variation in an integrated circuit. Our method requires only a test chip, a personal computer, a cheap digital-to-analog converter, a controller and multimeters, and thus large volume measurement can be performed on an office desk at low cost. To demonstrate the proposed method, we designed a test chip with a current model logic driver and an array of 128 current mirrors that mimic the random process variation of the driver's tail current mirror. Using our method, we characterized the random process variation of the driver's voltage due to the random process variation on the driver's tail current mirror from large volume measurement data. The statistical characteristics of the driver's output voltage calculated from the measured data are compared with Monte Carlo simulation. The difference between the measured and the simulated averages and standard deviations are less than 20% showing that we can easily characterize the random process variation at low cost by using our cost-efficient automatic large data acquisition method.

Worst Case Sampling Method with Confidence Ellipse for Estimating the Impact of Random Variation on Static Random Access Memory (SRAM)

  • Oh, Sangheon;Jo, Jaesung;Lee, Hyunjae;Lee, Gyo Sub;Park, Jung-Dong;Shin, Changhwan
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.15 no.3
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    • pp.374-380
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    • 2015
  • As semiconductor devices are being scaled down, random variation becomes a critical issue, especially in the case of static random access memory (SRAM). Thus, there is an urgent need for statistical methodologies to analyze the impact of random variations on the SRAM. In this paper, we propose a novel sampling method based on the concept of a confidence ellipse. Results show that the proposed method estimates the SRAM margin metrics in high-sigma regimes more efficiently than the standard Monte Carlo (MC) method.

Stochastic response of colored noise parametric system

  • Heo, Hoon;Paik, Jong-Han;Oh, Jin-Hyoung
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10b
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    • pp.451-455
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    • 1993
  • Interaction between system and disturbance results in system with time-dependent parameter. Parameter variation due to interaction has random characteristics. Most of the randomly varying parameters in control problem is regarded as white noise random process which is not a realistic model. In real situation those random variation is colored noise random process. Modified F-P-K equation is proposed to get the response of the random parametric system using some correction factor. Proposed technique is employed to obtain the colored noise parametric system response and confirmed via Monte-Carlo Simulation.

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A Study on economically optimal Determination of the Parameters of the Stratified Random Sampling (확률추출에 의한 층별 샘플링의 경제성에 관한 연구)

  • 황의철;이영식
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.13 no.21
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    • pp.81-90
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    • 1990
  • In stratified random sampling a simple random sample must be taken in each stratum to reduce the maximum gain in precision given the minimum cost. The purpose of this paper is to deal with the propertics of the estimates and variances and obtain the economic design of stratified random sampling through the optimum allocation of the sample sizes. In addition, the between stratum variation and the within stratum variation is stratifying the population are described.

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Free vibration analysis of rotating beams with random properties

  • Hosseini, S.A.A.;Khadem, S.E.
    • Structural Engineering and Mechanics
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    • v.20 no.3
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    • pp.293-312
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    • 2005
  • In this paper, free vibration of rotating beam with random properties is studied. The cross-sectional area, elasticity modulus, moment of inertia, shear modulus and density are modeled as random fields and the rotational speed as a random variable. To study uncertainty, stochastic finite element method based on second order perturbation method is applied. To discretize random fields, the three methods of midpoint, interpolation and local average are applied and compared. The effects of rotational speed, setting angle, random property variances, discretization scheme, number of elements, correlation of random fields, correlation function form and correlation length on "Coefficient of Variation" (C.O.V.) of first mode eigenvalue are investigated completely. To determine the significant random properties on the variation of first mode eigenvalue the sensitivity analysis is performed. The results are studied for both Timoshenko and Bernoulli-Euler rotating beam. It is shown that the C.O.V. of first mode eigenvalue of Timoshenko and Bernoulli-Euler rotating beams are approximately identical. Also, compared to uncorrelated random fields, the correlated case has larger C.O.V. value. Another important result is, where correlation length is small, the convergence rate is lower and more number of elements are necessary for convergence of final response.

Characteristic Analysis of Particulate Composites According to a Random Microstructure (랜덤 미세구조에 따른 입자 복합재료의 특성분석)

  • Park, Cheon;Kang, Young-Jin;Noh, Yoojeong;Lim, O-Kaung
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.1
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    • pp.23-30
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    • 2017
  • Since shape, size and distribution of particles in particulate composites have spreaded characteristics, properties of particulate composites have variation and also system behavior using particulate composites have variation. However, it is difficult to consider spreaded characteristic of particles so that a system behavior is analysed using homogeneous techniques or using microstructure in local areas. In this study, for considering random variation of particles, RMDFs(random morphology description functions) are used to generate random microstructure and relationship between the number of gaussian functions and spreaded characteristic of particles was analysed using the geometrical moment of area. Also, multi-scale analysis was carried out for cantilever beam with full-random microstructure to study behavior of particulate composites structure. As a result, it is defined that spreaded characteristic of particles and the variation of deflections of cantilever beam are decreased as the number of Gaussian functions(N) is increased and converges at N=200.

Analysis of Random Variations and Variation-Robust Advanced Device Structures

  • Nam, Hyohyun;Lee, Gyo Sub;Lee, Hyunjae;Park, In Jun;Shin, Changhwan
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.14 no.1
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    • pp.8-22
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    • 2014
  • In the past few decades, CMOS logic technologies and devices have been successfully developed with the steady miniaturization of the feature size. At the sub-30-nm CMOS technology nodes, one of the main hurdles for continuously and successfully scaling down CMOS devices is the parametric failure caused by random variations such as line edge roughness (LER), random dopant fluctuation (RDF), and work-function variation (WFV). The characteristics of each random variation source and its effect on advanced device structures such as multigate and ultra-thin-body devices (vs. conventional planar bulk MOSFET) are discussed in detail. Further, suggested are suppression methods for the LER-, RDF-, and WFV-induced threshold voltage (VTH) variations in advanced CMOS logic technologies including the double-patterning and double-etching (2P2E) technique and in advanced device structures including the fully depleted silicon-on-insulator (FD-SOI) MOSFET and FinFET/tri-gate MOSFET at the sub-30-nm nodes. The segmented-channel MOSFET (SegFET) and junctionless transistor (JLT) that can suppress the random variations and the SegFET-/JLT-based static random access memory (SRAM) cell that enhance the read and write margins at a time, though generally with a trade-off between the read and the write margins, are introduced.

A Stochastic Analysis of Crack Propagation Life under Constant Amplitude Loading (균일진폭 하중하에서의 확률론적 균열진전 수명해석)

  • 윤한용;양영순;윤장호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.9
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    • pp.1691-1699
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    • 1992
  • The experimental results of fatigue crack propagation under constant amplitude loading show that intra-and inter-specimen variability exist. In this paper, a stochastic model for the estimation of mean and variance of crack propagation life is presented To take into account the intra-specimen variability, the material resistance against crack propagation is treated as an 1-dimensional spatial stochastic process, i. e. random field, varying along the propagation path. For the inter-specimen variability, C in paris equation is assumed to be a random variable. Compared with experimental results reported, the present method well estimate the variation in fatigue crack propagation life. And it is confirmed that the thicker the specimen thickness is, the less the variation of propagation life is.

RESPONSE ANALYSIS OF A STOCHSTIC UNDER PARAMETRIC ND EXTERNL EXCITATION HAVING COLORED NOISE CHARACTERISTICS (유색잡음 매개변수가진과 외부가진을 받는 확률 시스템의 응답해석)

  • Heo, Hoon;Paik, Jong-Han;Oh, Jin-Hyong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1993.10a
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    • pp.55-59
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    • 1993
  • Interaction between system and disturbance results in system with time-dependent parameter. Parameter variation due to interaction has random characteristics. Most of the randomly varying parameters in control problem is regarded as white noise random process, which is not a realistic model. In real situation those random variation is colored noise random process. Modified F-P-K equation is proposed to get the response of the random parametric system using some correction factor. Proposed technique is employed to obtain the colored noise parametric system response and confirmed via Monte-Carlo Simulation.

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