scholarly journals Study of the temporal distribution density of the shot sheaf span to create a simulation model of the optical sensor signal

2021 ◽  
Vol 5 (45) ◽  
pp. 779-783
Author(s):  
A.Yu. Vdovin
Keyword(s):  
Simulation Model ◽  
Optical Sensor ◽  
Mathematical Expectation ◽  
Distribution Density ◽  
Scale Parameter ◽  
Measurement Data ◽  
Temporal Distribution ◽  
Rayleigh Distribution ◽  
Time Span ◽  
Sensor Signal

When studying the space path of a cloud of pellets from a shotgun and evaluating its parameters, it is advisable to have a simulation model of the optical sensor signal when a shot sheaf crosses the light screen. To create such a model, you need to get the relationship between the scale parameter in the Rayleigh distribution and the time span of the shot sheaf. Studies of the temporal distribution density of the shot sheaf span are performed, and graphs of the distribution density of the span for near-real situations are constructed. A linear dependence of the mathematical expectation of the span distribution density on the scale parameter in the Rayleigh distribution is established. A simplified expression is obtained for calculating the mathematical expectation of the time span of the shot sheaf. Statistical modeling confirmed the possibility of the practical use of the proposed formulas, including with a large number of pellets (up to 1000). The dependence of the mathematical expectation of the span on the number of pellets is investigated, its approximation by various functions is carried out, and the approximation errors are estimated. The research conducted allows us to create a simulation model of the optical sensor signal when the shot sheaf crosses the light screen on the basis of empirical data on the real-signal duration (with averaged measurement data for several shots being helpful).

scholarly journals On double stage minimax-shrinkage estimator for generalized Rayleigh model

2016 ◽  
Vol 5 (1) ◽  
pp. 39 ◽  
Author(s):  
Abbas Najim Salman ◽  
Maymona Ameen
Keyword(s):  
Sample Size ◽  
Shape Parameter ◽  
Mean Squared Error ◽  
Scale Parameter ◽  
Rayleigh Distribution ◽  
Shrinkage Estimator ◽  
Squared Error ◽  
Expected Sample Size ◽  
Generalized Rayleigh Distribution ◽  
The Mean

<p>This paper is concerned with minimax shrinkage estimator using double stage shrinkage technique for lowering the mean squared error, intended for estimate the shape parameter (a) of Generalized Rayleigh distribution in a region (R) around available prior knowledge (a<sub>0</sub>) about the actual value (a) as initial estimate in case when the scale parameter (l) is known .</p><p>In situation where the experimentations are time consuming or very costly, a double stage procedure can be used to reduce the expected sample size needed to obtain the estimator.</p><p>The proposed estimator is shown to have smaller mean squared error for certain choice of the shrinkage weight factor y(<strong>×</strong>) and suitable region R.</p><p>Expressions for Bias, Mean squared error (MSE), Expected sample size [E (n/a, R)], Expected sample size proportion [E(n/a,R)/n], probability for avoiding the second sample and percentage of overall sample saved  for the proposed estimator are derived.</p><p>Numerical results and conclusions for the expressions mentioned above were displayed when the consider estimator are testimator of level of significanceD.</p><p>Comparisons with the minimax estimator and with the most recent studies were made to shown the effectiveness of the proposed estimator.</p>

scholarly journals Wind speed modeling based on measurement data to predict future wind speed with modified Rayleigh model

2021 ◽  
Vol 12 (3) ◽  
pp. 1823
Author(s):  
Suwarno Suwarno ◽  
Rohana Rohana
Keyword(s):  
Wind Speed ◽  
Measurement Data ◽  
Rayleigh Distribution ◽  
Scale Factor ◽  
Percentage Error ◽  
Monthly Data ◽  
Wind Speeds ◽  
Wind Characteristics ◽  
One Year ◽  
The Many

The development of modeling wind speed plays a very important in helping to obtain the actual wind speed data for the benefit of the power plant planning in the future. The wind speed in this paper is obtained from a PCE-FWS 20 type measuring instrument with a duration of 30 minutes which is accumulated into monthly data for one year (2019). Despite the many wind speed modeling that has been done by researchers. Modeling wind speeds proposed in this study were obtained from the modified Rayleigh distribution. In this study, the Rayleigh scale factor (<em>C<sub>r</sub></em>) and modified Rayleigh scale factor (<em>C<sub>m</sub></em>) were calculated. The observed wind speed is compared with the predicted wind characteristics. The data fit test used correlation coefficient (R<sup>2</sup>), root means square error (RMSE), and mean absolute percentage error (MAPE). The results of the proposed modified Rayleigh model provide very good results for users.

A Study of Impeller-Diffuser-Volute Interaction in a Centrifugal Fan

2005 ◽  
Vol 127 (1) ◽  
pp. 84-90 ◽  
Author(s):  
Tarek Meakhail ◽  
Seung O. Park
Keyword(s):  
Simulation Model ◽  
Velocity Measurement ◽  
Measurement Data ◽  
Flow Simulation ◽  
Separated Flow ◽  
Quantitative Agreement ◽  
Initial Guess ◽  
Centrifugal Fan ◽  
Vaned Diffuser ◽  
Commercial Code

This paper reports velocity measurement data in the interaction region between the impeller and vaned diffuser and the results of numerical flow simulation of the whole machine (impeller, vaned diffuser and volute) of a single stage centrifugal fan. Two-dimensional instantaneous velocity measurement is done using particle image velocimetry (PIV). Numerical simulation of impeller-diffuser-volute interaction is performed using CFX-Tascflow commercial code. A frozen rotor simulation model is used for the steady calculation and a rotor-stator simulation model is used for the unsteady calculation using the steady results as an initial guess. The simulation results show that the separated flow regime near the diffuser hub extends to the volute. Comparison between the unsteady computation and those of measurement indicates that the rotor/stator model employed in the simulation predicts essential characteristics of unsteady flow in the centrifugal fan. However, quantitative agreement remains rather poor.

Study on the Finite Element Strain Simulation Model Updating Method Based on the Real Measurement Data

2013 ◽  
Vol 444-445 ◽  
pp. 1132-1139
Author(s):  
Li Feng Xiao ◽  
Ran Duan ◽  
Hui Tian
Keyword(s):  
Finite Element ◽  
Simulation Model ◽  
Model Updating ◽  
Measurement Data ◽  
Estimation Method ◽  
Element Model ◽  
Boundary Region ◽  
Strain Data ◽  
Before And After ◽  
Kriging Estimation

When using electrometric method to measure the static strain of a structure, the results are often accurate, but the number of measuring points is limited; when using the finite element method to model and analyze the practical structures, there often exist many assumptions of uncertain factors, so the accuracy of simulation results is poor, but the strain values of all the nodes in the grid of simulation structure are available, so the number of measuring points is large. In view of this situation, this paper applied Bayes-Kriging estimation method through the measurement strain data to update the strain on the surface of finite element strain simulation model. We applied the measurement strain data at different stages of the fatigue process to update finite element model. With the comparison of the strain data between before-and after-updating, we can find that at the boundary region and fatigue crack extending direction, the updating result is inaccurate, but the updating effect is good at other position. This method can improve the accuracy of these positions' strain value and make the strain value closer to the actual strain value.

Analyzing wind speed data and wind power density of Tetouan city in Morocco by adjustment to Weibull and Rayleigh distribution functions

2017 ◽  
Vol 41 (3) ◽  
pp. 174-184 ◽  
Author(s):  
Mohamed Hatim Ouahabi ◽  
Farid Benabdelouahab ◽  
Abdellatif Khamlichi
Keyword(s):  
Wind Speed ◽  
Measurement Data ◽  
Rayleigh Distribution ◽  
Distribution Functions ◽  
Statistical Distributions ◽  
Energy Potential ◽  
Distribution Models ◽  
Wind Speed Data ◽  
Resource Characteristics ◽  
Wind Resource

Several statistical distributions have been considered to model wind speed data. However, Weibull and Rayleigh statistical distributions are the most widely used methods for analyzing wind speed measurements and determining wind energy potential. In this work, these statistical distributions were applied in order to evaluate the wind resources in the northern Moroccan city of Tetouan. Adjustment of wind measurement data was performed. Then, the obtained results were compared with the provided wind data to test their accuracy based on common statistical indicators for performance. It was found that the Weibull and Rayleigh distribution models provide adequate description of the frequencies of actual wind records in Tetouan. They can be advantageously used to assess wind resource characteristics in this region.

scholarly journals Applying the Shrinkage Technique for Estimating the Scale Parameter of Weighted Rayleigh Distribution

2020 ◽  
pp. 2335-2340
Author(s):  
Intesar Obeid Hassoun ◽  
Adel Abdulkadhim Hussein
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Mean Squared Error ◽  
Scale Parameter ◽  
Rayleigh Distribution ◽  
Squared Error ◽  
Simulation Based

This paper includes the estimation of the scale parameter of weighted Rayleigh distribution using well-known methods of estimation (classical and Bayesian). The proposed estimators were compared using Monte Carlo simulation based on mean squared error (MSE) criteria. Then, all the results of simulation and comparisons were demonstrated in tables. 

scholarly journals Two Different Classes of Shrinkage Estimators for the Scale Parameter of the Rayleigh Distribution

2021 ◽  
Vol 19 (1) ◽  
pp. 2-21
Author(s):  
Talha Omer ◽  
Zawar Hussain ◽  
Muhammad Qasim ◽  
Said Farooq Shah ◽  
Akbar Ali Khan
Keyword(s):  
Simulation Study ◽  
Mean Squared Error ◽  
Scale Parameter ◽  
Rayleigh Distribution ◽  
Shrinkage Estimators ◽  
Unbiased Estimators ◽  
Squared Error ◽  
The Mean ◽  
Simulation Results

Shrinkage estimators are introduced for the scale parameter of the Rayleigh distribution by using two different shrinkage techniques. The mean squared error properties of the proposed estimator have been derived. The comparison of proposed classes of the estimators is made with the respective conventional unbiased estimators by means of mean squared error in the simulation study. Simulation results show that the proposed shrinkage estimators yield smaller mean squared error than the existence of unbiased estimators.

Simulating Crime Against Properties Using Swarm Intelligence and Social Networks

2011 ◽  
pp. 1142-1159
Author(s):  
Vasco Furtado ◽  
Adriano Melo ◽  
André L.V. Coelho ◽  
Ronaldo Menezes ◽  
Mairon Belchior
Keyword(s):  
Social Networks ◽  
Spatial Distribution ◽  
Simulation Model ◽  
Swarm Intelligence ◽  
Criminal Behavior ◽  
Temporal Distribution ◽  
Social Aspect ◽  
Urban Centers ◽  
Distribution Profile ◽  
Learning Factors

Experience in the domain of criminology has shown that the spatial distribution of some types of crimes in urban centers follows Zipf’s Law in which most of the crime events are concentrated in a few places while other places have few crimes. Moreover, the temporal distribution of these crime events follows an exponential law. In order to reproduce and better understand the nuances of such crime distribution profile, we introduce in this chapter a novel multi-agent-based crime simulation model that is directly inspired by the swarm intelligence paradigm. In this model, criminals are regarded as agents endowed with the capability to pursue self-organizing behavior by considering their individual (local) activities as well as the influence of other criminals pertaining to their social networks. Through controlled experiments with the simulation model, we could indeed observe that self-organization phenomena (i.e., criminal behavior toward crime) emerge as the result of both individual and social learning factors. As expected, our experiments reveal that the spatial distribution of crime occurrences achieved with the simulation model provides a good approximation of the real-crime data distribution. A detailed analysis of the social aspect is also conducted here as this factor is shown to be instrumental for the accurate reproduction of the spatial pattern of crime occurrences.

On estimating the scale parameter of the Rayleigh distribution from doubly censored samples

1980 ◽  
Vol 21 (1) ◽  
pp. 14-29 ◽  
Author(s):  
Kwan R. Lee ◽  
C. H. Kapadia ◽  
Dwight B. Brock
Keyword(s):  
Scale Parameter ◽  
Rayleigh Distribution ◽  
Censored Samples ◽  
Doubly Censored
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