Evaluation of cross-ply laminate stiffness with a non-uniform distribution of transverse matrix cracks by means of a computational meso-mechanic model

2018 ◽  
Vol 185 ◽  
pp. 561-572 ◽  
Author(s):  
Néstor Darío Barulich ◽  
Luis Augusto Godoy ◽  
Patricia Mónica Dardati
Keyword(s):  
Uniform Distribution ◽  
Mechanic Model ◽  
Matrix Cracks

Levels taxation countries the EU and Ukraine’s

2019 ◽  
pp. 131-160
Author(s):  
Helena Borzenko ◽  
Tamara Panfilova ◽  
Mikhail Litvin
Keyword(s):  
European Union ◽  
Uniform Distribution ◽  
Tax Burden ◽  
Tax System ◽  
Tax Legislation ◽  
Improvement Process ◽  
Tax Systems ◽  
Historical Comparative ◽  
Different Levels ◽  
The Eu

Purpose articles rassm and experience and benefits systems taxation countries European Union, manifestation iti the main limitations domestic taxlegislation and wired STI their comparisons. In general iti ways the provisiontax reporting countries Eurozone in the appropriate organs, dove STI need theintroduction Ukraine electronic methods receiving and processing such reports.define iti key directions reforming domestic tax legislation. Methodology research is to use aggregate methods: dialectical, statistical, historical, comparative. Scientific novelty is to are provided recommendations for improvement ofefficiency systems taxation of our states in international ratings characterizingtax institutions country. Therefore, despite some problems in legislation heldcomparative study systems taxation EU and Ukraine. Conclucions Coming fromof this, the main directions reforming tax systems Ukraine, in our opinion,today should become: improvement process administration, reduce scales evasiontaxes, provision more uniform distribution tax burden between taxpayers, themaximum cooperation tax bodies different levels as well adjustment systemselectronic interactions tax authorities and payers, tax system must contain ascan less unfounded benefits, consistent with the general by politics pricing.

Statistical Justification of Pearson's Criterion for Testing a Complex Hypothesis on the Uniform Distribution

2018 ◽  
pp. 45-53
Author(s):  
T. V. Oblakova
Keyword(s):  
Uniform Distribution ◽  
Degrees Of Freedom ◽  
Likelihood Function ◽  
Random Number Generator ◽  
Maximum Likelihood Estimates ◽  
Chi Square ◽  
Main Hypothesis ◽  
Pearson Criterion ◽  
Complex Hypothesis ◽  
Uniform Law

The paper is studying the justification of the Pearson criterion for checking the hypothesis on the uniform distribution of the general totality. If the distribution parameters are unknown, then estimates of the theoretical frequencies are used [1, 2, 3]. In this case the quantile of the chi-square distribution with the number of degrees of freedom, reduced by the number of parameters evaluated, is used to determine the upper threshold of the main hypothesis acceptance [7]. However, in the case of a uniform law, the application of Pearson's criterion does not extend to complex hypotheses, since the likelihood function does not allow differentiation with respect to parameters, which is used in the proof of the theorem mentioned [7, 10, 11].A statistical experiment is proposed in order to study the distribution of Pearson statistics for samples from a uniform law. The essence of the experiment is that at first a statistically significant number of one-type samples from a given uniform distribution is modeled, then for each sample Pearson statistics are calculated, and then the law of distribution of the totality of these statistics is studied. Modeling and processing of samples were performed in the Mathcad 15 package using the built-in random number generator and array processing facilities.In all the experiments carried out, the hypothesis that the Pearson statistics conform to the chi-square law was unambiguously accepted (confidence level 0.95). It is also statistically proved that the number of degrees of freedom in the case of a complex hypothesis need not be corrected. That is, the maximum likelihood estimates of the uniform law parameters implicitly used in calculating Pearson statistics do not affect the number of degrees of freedom, which is thus determined by the number of grouping intervals only.

A Time Petri Net Model Based on Uniform Distribution

2010 ◽  
Vol 33 (5) ◽  
pp. 900-907 ◽  
Author(s):  
Li PAN ◽  
Zhi-Jun DING ◽  
Gang CHEN
Keyword(s):  
Uniform Distribution ◽  
Petri Net ◽  
Model Based ◽  
Time Petri Net

scholarly journals Handling coarsened age information in the analysis of emergency department presentations

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Rhonda J. Rosychuk ◽  
Jeff W.N. Bachman ◽  
Anqi Chen ◽  
X. Joan Hu
Keyword(s):  
Emergency Department ◽  
Sample Size ◽  
Uniform Distribution ◽  
Empirical Distribution ◽  
Data Access ◽  
Recurrent Event ◽  
Fiscal Year ◽  
Recurrent Event Data ◽  
Higher Ed ◽  
Ed Visits

Abstract Background Administrative databases offer vast amounts of data that provide opportunities for cost-effective insights. They simultaneously pose significant challenges to statistical analysis such as the redaction of data because of privacy policies and the provision of data that may not be at the level of detail required. For example, ages in years rather than birthdates available at event dates can pose challenges to the analysis of recurrent event data. Methods Hu and Rosychuk provided a strategy for estimating age-varying effects in a marginal regression analysis of recurrent event times when birthdates are all missing. They analyzed emergency department (ED) visits made by children and youth and privacy rules prevented all birthdates to be released, and justified their approach via a simulation and asymptotic study. With recent changes in data access rules, we requested a new extract of data for April 2010 to March 2017 that includes patient birthdates. This allows us to compare the estimates using the Hu and Rosychuk (HR) approach for coarsened ages with estimates under the true, known ages to further examine their approach numerically. The performance of the HR approach under five scenarios is considered: uniform distribution for missing birthdates, uniform distribution for missing birthdates with supplementary data on age, empirical distribution for missing birthdates, smaller sample size, and an additional year of data. Results Data from 33,299 subjects provided 58,166 ED visits. About 67% of subjects had one ED visit and less than 9% of subjects made over three visits during the study period. Most visits (84.0%) were made by teenagers between 13 and 17 years old. The uniform distribution and the HR modeling approach capture the main trends over age of the estimates when compared to the known birthdates. Boys had higher ED visit frequencies than girls in the younger ages whereas girls had higher ED visit frequencies than boys for the older ages. Including additional age data based on age at end of fiscal year did not sufficiently narrow the widths of potential birthdate intervals to influence estimates. The empirical distribution of the known birthdates was close to a uniform distribution and therefore, use of the empirical distribution did not change the estimates provided by assuming a uniform distribution for the missing birthdates. The HR approach performed well for a smaller sample size, although estimates were less smooth when there were very few ED visits at some younger ages. When an additional year of data is added, the estimates become better at these younger ages. Conclusions Overall the Hu and Rosychuk approach for coarsened ages performed well and captured the key features of the relationships between ED visit frequency and covariates.

Oriented and Uniform Distribution of Dion–Jacobson Phase Perovskites Controlled by Quantum Well Barrier Thickness

Solar RRL ◽  
2019 ◽  
Vol 3 (9) ◽  
pp. 1900090 ◽  
Author(s):  
Yiting Zheng ◽  
Tingting Niu ◽  
Jian Qiu ◽  
Lingfeng Chao ◽  
Bixin Li ◽  
...  
Keyword(s):  
Quantum Well ◽  
Uniform Distribution ◽  
Barrier Thickness

scholarly journals Random additions in urns of integers

2021 ◽  
Vol 58 (2) ◽  
pp. 335-346
Author(s):  
Mackenzie Simper
Keyword(s):  
Finite Group ◽  
Random Process ◽  
Uniform Distribution ◽  
Discrete Time ◽  
Random Variable ◽  
Urn Model ◽  
Infinite Type ◽  
The Mean ◽  
A Finite Group ◽  
Proof Of Convergence

AbstractConsider an urn containing balls labeled with integer values. Define a discrete-time random process by drawing two balls, one at a time and with replacement, and noting the labels. Add a new ball labeled with the sum of the two drawn labels. This model was introduced by Siegmund and Yakir (2005) Ann. Prob.33, 2036 for labels taking values in a finite group, in which case the distribution defined by the urn converges to the uniform distribution on the group. For the urn of integers, the main result of this paper is an exponential limit law. The mean of the exponential is a random variable with distribution depending on the starting configuration. This is a novel urn model which combines multi-drawing and an infinite type of balls. The proof of convergence uses the contraction method for recursive distributional equations.

scholarly journals Structural Damage Identification of Composite Rotors Based on Fully Connected Neural Networks and Convolutional Neural Networks

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2005
Author(s):  
Veronika Scholz ◽  
Peter Winkler ◽  
Andreas Hornig ◽  
Maik Gude ◽  
Angelos Filippatos
Keyword(s):  
Neural Networks ◽  
Convolutional Neural Networks ◽  
Composite Structures ◽  
Damage Identification ◽  
Vibration Response ◽  
Damage Initiation ◽  
Matrix Cracks ◽  
Operational Life ◽  
Multiple Data Sets ◽  
Fully Connected

Damage identification of composite structures is a major ongoing challenge for a secure operational life-cycle due to the complex, gradual damage behaviour of composite materials. Especially for composite rotors in aero-engines and wind-turbines, a cost-intensive maintenance service has to be performed in order to avoid critical failure. A major advantage of composite structures is that they are able to safely operate after damage initiation and under ongoing damage propagation. Therefore, a robust, efficient diagnostic damage identification method would allow monitoring the damage process with intervention occurring only when necessary. This study investigates the structural vibration response of composite rotors by applying machine learning methods and the ability to identify, localise and quantify the present damage. To this end, multiple fully connected neural networks and convolutional neural networks were trained on vibration response spectra from damaged composite rotors with barely visible damage, mostly matrix cracks and local delaminations using dimensionality reduction and data augmentation. A databank containing 720 simulated test cases with different damage states is used as a basis for the generation of multiple data sets. The trained models are tested using k-fold cross validation and they are evaluated based on the sensitivity, specificity and accuracy. Convolutional neural networks perform slightly better providing a performance accuracy of up to 99.3% for the damage localisation and quantification.

Sign in / Sign up

Export Citation Format

Share Document