scholarly journals Stratification of populations with skewed distribution

2021 ◽  
Vol 47 ◽  
Author(s):  
Dalius Pumputis
Keyword(s):  
Skewed Distribution ◽  
Geometric Method ◽  
Power Method ◽  
Frequency Method ◽  
Stratification Method ◽  
Simulation Results ◽  
Root Frequency

The problem of efficient stratification in the case of skewed population is considered. Four stratification methods are examined. A new adjusted geometric stratification method is introduced. This method is compared by simulation with the Dalenius-Hodges cumulative root frequency method, the geometric method proposed by Gunning and Horgan [2], and the power method offered by Plikusas in [6]. The simulation results show that in most cases considered the power method is the most efficient one.

An Improved FFT Algorithm and its Application in the Measurement of Grounding Resistance

2012 ◽  
Vol 546-547 ◽  
pp. 260-265
Author(s):  
Wen Yan Chen ◽  
Hang Tuo
Keyword(s):  
Measurement Accuracy ◽  
Measurement Precision ◽  
Resistance Measurement ◽  
Harmonic Amplitude ◽  
Frequency Method ◽  
Grounding Resistance ◽  
Amplitude Correction ◽  
Interference Signals ◽  
Simulation Results ◽  
Grounding Resistance Measurement

For the problems of noise and clutter interference in the measurement of grounding resistance, the article designs a grounding resistance measurement method based on an improved FFT algorithm. We deduce the harmonic amplitude correction formula which can more accurately measure the frequency of the interference signals and the amplitude of the effective signals, and thus improve the measurement accuracy of grounding resistance. This paper also devises a grounding resistance measurement scheme combining the algorithm and the variation-frequency method. The simulation results and the validation of experimental data show that, the algorithm evidently reduces the noise and improves the measurement precision. The algorithm is of high practical value to the grounding resistance measurement.

Autonomous Collision Imminent Steering Maneuver in Presence of Surrounding Obstacles

2016 ◽  
Author(s):  
Rouhollah Jafari ◽  
Shuqing Zeng ◽  
Nikolai Moshchuk
Keyword(s):  
Path Planning ◽  
Real Time ◽  
Collision Avoidance ◽  
Geometric Method ◽  
Target Vehicle ◽  
Virtual Target ◽  
Planning Algorithm ◽  
Simulation Results ◽  
Collision Avoidance System ◽  
Path Planning Algorithm

In this paper, a collision avoidance system is proposed to steer away from a leading target vehicle and other surrounding obstacles. A virtual target lane is generated based on an object map resulted from perception module. The virtual target lane is used by a path planning algorithm for an evasive steering maneuver. A geometric method which is computationally fast for real-time implementations is employed. The algorithm is tested in real-time and the simulation results suggest the effectiveness of the system in avoiding collision with not only the leading target vehicle but also other surrounding obstacles.

scholarly journals Control Charts for Joint Monitoring of the Lognormal Mean and Standard Deviation

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 549
Author(s):  
Wei-Heng Huang
Keyword(s):  
Standard Deviation ◽  
Lognormal Distribution ◽  
Control Charts ◽  
Skewed Distribution ◽  
Process Mean ◽  
Joint Monitoring ◽  
Simulation Results

The Shewhart X¯- and S-charts are most commonly used for monitoring the process mean and variability based on the assumption of normality. However, many process distributions may follow a positively skewed distribution, such as the lognormal distribution. In this study, we discuss the construction of three combined X¯- and S-charts for jointly monitoring the lognormal mean and the standard deviation. The simulation results show that the combined lognormal X¯- and S-charts are more effective when the lognormal distribution is more skewed. A real example is used to demonstrate how the combined lognormal X¯- and S-charts can be applied in practice.

A geometric approach to manipulator path planning in 3D space in the presence of obstacles

Robotica ◽  
1992 ◽  
Vol 10 (4) ◽  
pp. 321-328
Author(s):  
Manja Kirćanski ◽  
Olga Timčenko
Keyword(s):  
Euclidean Space ◽  
Path Planning ◽  
Real Time ◽  
Control Level ◽  
Geometric Approach ◽  
Geometric Method ◽  
Reachable Workspace ◽  
3D Space ◽  
Simulation Results ◽  
Polyhedral Obstacles

SUMMARYThe paper presents a geometric method for collision-free manipulator path planning in 3D Euclidean space with polyhedral obstacles. It ensures that none of the links nor the manipulator tip collide with the objects. The method is computationally very cheap and it does not require intensive off-line preprocessing. Hence, it is real-time applicable if the information about obstacles positions and shapes is obtained from a higher control level. The trajectories generated lie within the reachable workspace. The method is implemented on a VAX 11/750 computer and the simulation results are included.

Precision Analysis and Simulation of Locating the Single Source Based on Double-UAVs

2013 ◽  
Vol 347-350 ◽  
pp. 3769-3773
Author(s):  
Qiu Ju Zhang ◽  
Shao Rong Xie ◽  
Jun Luo ◽  
Yan Peng ◽  
Zhou Hao Ye
Keyword(s):  
Performance Analysis ◽  
Direction Finding ◽  
Geometric Method ◽  
Single Source ◽  
Precision Analysis ◽  
Positioning Accuracy ◽  
Great Achievement ◽  
Simulation Results ◽  
And Performance ◽  
Passive Localization

The passive direction finding cross localization has got great achievement and has been widely used in military and civilian fields. Currently, the researches on passive localization have focused on AOA, TDOA and FDOA. In our system, the passive direction finding cross localization is more effective and useful. We use two UAVs to locate a single source. We apply the geometric method to analysis positioning accuracy. In order to study the performance of a passive direction finding cross localization, MATLAB is used to simulate the result. Finally, the simulation results and performance analysis provide operational technical principle for such a system.

scholarly journals An Analysis of Extent of Use of Online Utility Services in Punjab, India

2020 ◽  
pp. 109-117
Author(s):  
Anupriya Nayal ◽  
Preeti Sharma
Keyword(s):  
Urban Areas ◽  
Structured Interview ◽  
Cube Root ◽  
Mobile Banking ◽  
Frequency Method ◽  
Interval Method ◽  
Utility Services ◽  
Spss Software ◽  
Descriptive Survey ◽  
Root Frequency

Aim: To analyze the extent of use of online utility services. Study Design: Descriptive survey research design. Place and Duration of Study: Rural (Doraha and Sidhwan Bet block), peri-urban (Ayali Kalan, Sunet and Threeke villages of Ludhiana I block) and urban areas of Ludhiana district, between August 2018 to May 2019. Methodology: Using a structured interview schedule, data was collected randomly from 180 respondents having sixty online utility service users each from rural, peri-urban and urban areas of Ludhiana district of Punjab, India. The statistical tools such as frequency distribution, percentage, arithmetic mean, category interval method, Kruskal Wallis H-test for k independent samples and cumulative cube root frequency method were used for the analysis of data along with Statistical Package for Social Sciences (SPSS) software. Results: Overall, higher percentage of the respondents had moderate to high extent of use of online utility services and were using them for bill payment, online/mobile banking, entertainment, online shopping and for other miscellaneous services. Conclusion: Extent of use of different online utility services was comparatively higher among urban respondents.

scholarly journals Geometric stratification of accounting data

2004 ◽  
Author(s):  
PATRICA GUNNING ◽  
JANE MARY HORGAN ◽  
WILLIAM YANCEY
Keyword(s):  
The Other ◽  
New Method ◽  
Frequency Method ◽  
Accounting Data ◽  
The Us ◽  
Use Tax ◽  
Root Frequency

WE SUGGEST A NEW PROCEDURE FOR DEFINING THE BOUNDARIES OF THE STRATA IN HIGHLY SKEWED POPULATIONS, USUAL IN AUDITING, WHICH IS MUCH EASIER TO USE THAN THE COMMONLY USED CUMULATIVE ROOT FREQUENCY METHOD OF DALENIUS AND HODGES (1957, 1959). WE IMPLEMENT IT ON TWO AUDIT POPULATIONS, ONE A POPULATION OF DEBTORS IN AN IRISH FIRM, AND THE OTHER A POPULATION OF SALES AND USE TAX LIABILITIES IN THE US. OUR RESULTS SHOW THAT THE NEW METHOD COMPARES FAVOURABLY WITH THE CUMULATIVE ROOT FREQUENCY METHOD IN TERMS OF THE ACCURACY OF THE ESTIMATES.

Clinically Meaningful Change

Methodology ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 97-105
Author(s):  
Rodrigo Ferrer ◽  
Antonio Pardo
Keyword(s):  
Effect Size ◽  
False Negative ◽  
False Negative Rate ◽  
Point Of View ◽  
Skewed Distribution ◽  
Effect Sizes ◽  
False Negatives ◽  
Large Size ◽  
Before And After ◽  
Post Test

Abstract. In a recent paper, Ferrer and Pardo (2014) tested several distribution-based methods designed to assess when test scores obtained before and after an intervention reflect a statistically reliable change. However, we still do not know how these methods perform from the point of view of false negatives. For this purpose, we have simulated change scenarios (different effect sizes in a pre-post-test design) with distributions of different shapes and with different sample sizes. For each simulated scenario, we generated 1,000 samples. In each sample, we recorded the false-negative rate of the five distribution-based methods with the best performance from the point of view of the false positives. Our results have revealed unacceptable rates of false negatives even with effects of very large size, starting from 31.8% in an optimistic scenario (effect size of 2.0 and a normal distribution) to 99.9% in the worst scenario (effect size of 0.2 and a highly skewed distribution). Therefore, our results suggest that the widely used distribution-based methods must be applied with caution in a clinical context, because they need huge effect sizes to detect a true change. However, we made some considerations regarding the effect size and the cut-off points commonly used which allow us to be more precise in our estimates.

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