Statistical Uncertainty Analyses of Void Fraction Predictions Using Two Different Sampling Strategies: Latin Hypercube and Simple Random Sampling

2010 ◽  
Author(s):  
Augusto Hernandez-Solis ◽  
Christian Ekberg ◽  
Arvid O¨dega˚rd Jensen ◽  
Christophe Demaziere ◽  
Ulf Bredolt
Keyword(s):  
Steady State ◽  
Sample Size ◽  
Void Fraction ◽  
Random Sampling ◽  
Simple Random Sampling ◽  
Statistical Uncertainty ◽  
Sampling Strategies ◽  
Latin Hypercube ◽  
Fine Mesh ◽  
Uncertainty Analyses

In recent years, a more realistic safety analysis of nuclear reactors has been based on best estimate (BE) computer codes. Because their predictions are unavoidably affected by conceptual, aleatory and experimental sources of uncertainty, an uncertainty analysis is needed if useful conclusions are to be obtained from BE codes. In this paper, statistical uncertainty analyses of cross-sectional averaged void fraction calculations using the POLCA-T system code, and based on the BWR Full-Size Fine-Mesh Bundle Test (BFBT) benchmark are presented by means of two different sampling strategies: Latin Hypercube (LHS) and Simple Random Sampling (SRS). LHS has the property of densely stratifying across the range of each input probability distribution, allowing a much better coverage of the input uncertainties than SRS. The aim here is to compare both uncertainty analyses on the BWR assembly void axial profile prediction in steady-state, and on the transient void fraction prediction at a certain axial level coming from a simulated re-circulation pump trip scenario. It is shown that the replicated void fraction mean (either in steady-state or transient conditions) has less variability when using LHS than SRS for the same number of calculations (i.e. same input space sample size) even if the resulting void fraction axial profiles are non-monotonic. It is also shown that the void fraction uncertainty limits achieved with SRS by running 458 calculations (sample size required to cover 95% of 8 uncertain input parameters with a 95% confidence), result in the same uncertainty limits achieved by LHS with only 100 calculations. These are thus clear indications on the advantages of using LHS.

scholarly journals Evaluating Sampling Methods for Content Analysis of Twitter Data

2018 ◽  
Vol 4 (2) ◽  
pp. 205630511877283 ◽  
Author(s):  
Hwalbin Kim ◽  
S. Mo Jang ◽  
Sei-Hill Kim ◽  
Anan Wan
Keyword(s):  
Social Media ◽  
South Carolina ◽  
Sample Size ◽  
Random Sampling ◽  
Sampling Methods ◽  
Empirical Studies ◽  
Simple Random Sampling ◽  
Media Content ◽  
Twitter Data ◽  
Gubernatorial Election

Despite the existing evaluation of the sampling options for periodical media content, only a few empirical studies have examined whether probability sampling methods can be applicable to social media content other than simple random sampling. This article tests the efficiency of simple random sampling and constructed week sampling, by varying the sample size of Twitter content related to the 2014 South Carolina gubernatorial election. We examine how many weeks were needed to adequately represent 5 months of tweets. Our findings show that a simple random sampling is more efficient than a constructed week sampling in terms of obtaining a more efficient and representative sample of Twitter data. This study also suggests that it is necessary to produce a sufficient sample size when analyzing social media content.

scholarly journals A Microcomputer Program for Assisting in the Design of Simple Random Samples

1987 ◽  
Vol 63 (6) ◽  
pp. 422-425 ◽  
Author(s):  
P. L. Marshall
Keyword(s):  
Sample Size ◽  
Key Words ◽  
Random Sampling ◽  
Simple Random Sampling ◽  
Percentage Error ◽  
Microcomputer Program ◽  
Random Samples ◽  
Potential Applications ◽  
The Relationship

An interactive microcomputer program was developed to aid the design of simple random sampling with or without replacement. The program determines: (1) sample size for a set of given conditions for up to 20 variables; (2) combinations of conditions that will yield a given samples size; and (3) the relationship between percentage error and sample size for a given set of conditions. Potential applications are illustrated with three simple examples. Key Words: sample size, simple random sampling

scholarly journals TINGKAT KECUKUPAN ZAT GIZI MAKRO DAN STATUS GIZI PASIEN TUBERKULOSIS DENGAN SPUTUM BTA (+) DAN SPUTUM BTA (–)

2018 ◽  
Vol 11 (2) ◽  
pp. 144
Author(s):  
Rina Wasesa Aprilia Lazulfa ◽  
Bambang Wirjatmadi ◽  
Merryana Adriani
Keyword(s):  
Infectious Disease ◽  
Weight Loss ◽  
Nutritional Status ◽  
Sample Size ◽  
Random Sampling ◽  
Simple Random Sampling ◽  
Nutrition Status ◽  
Sputum Smear ◽  
Level Energy ◽  
Cross Sectional

Tuberculosis is an infectious disease caused by mycobacterium t uberculosis germs. Germs in form of droplets spread through saliva splashes out when coughing, sneezing and talking then inhaled during breathing. The degree of sputum smear positivity of patients describe the increasing number of  tuberculosis bacteria in the lungs that could potentially transmit the infection. In general, patients with  tuberculosis have decreased appetite which impact on weight loss. This research was comparative observational analytic research using cross sectional approach with simple random sampling conducted at the Hospital Asy-Syaafi  Pamekasan with a sample size of 50 people. The results of Mann Whitney test showed a signifi cant difference in  adequacy level of energy (p= 0.026), carbohydrates (p = 0.000),  protein (p = 0.001), fat (p = 0.029) and nutritional status (p = 0.022) between the groups of  tuberculosis with sputum smear (+) and sputum smear (-). It was concluded that adequacy level (energy, p rotein, fat and carbohydrates) and nutrition status among respondents t uberculosis sputum smear (+) have signifi cant differences with the respondent t uberculosis sputum smear (-).

scholarly journals DESCRIPTION OF BILIRUBIN CONDITION CHECKING ON ALCOHOL CONSUMER IN EAST POHUWATO VILLAGE, POHUWATO DISTRICT

2021 ◽  
Vol 2 (1) ◽  
pp. 28-36
Author(s):  
Fransiska Polangitan ◽  
Dede Sutriono ◽  
Natan Pasiga
Keyword(s):  
Alcohol Consumption ◽  
Sample Size ◽  
Random Sampling ◽  
Sampling Technique ◽  
Simple Random Sampling ◽  
Descriptive Research ◽  
North Sulawesi ◽  
Alcohol Consumer ◽  
High Bilirubin

Based on 2014 WHO data, 61.7% of the world's population has consumed alcohol for more than 12 months which has caused around 3.3 million deaths or 5.9% of all deaths worldwide. For the 2018 RISKESDAS data in Indonesia, the first highest alcohol consumption area is North Sulawesi 16%, followed by East Nusa Tenggara 15.6, then Bali area 14%, and for Gorontalo area 11.3%. The purpose of this study was to determine the description of bilirubin levels in alcohol consumers in Pohuwato Timur Village, Pohuwato Regency including the length of time of consumption, age, types of drinks frequently consumed, frequency of alcohol consumption, and frequency of the amount of alcohol in one drink. This research uses descriptive research which is quantitative in nature. The population in the study was 55 samples with a sample size of 36 respondents who used the sampling technique, namely simple random sampling. The results showed that of the 36 respondents where the normal bilirubin levels were 14 respondents or if the percentage was 39%, while for the abnormal or high bilirubin levels there were 22 respondents or if the percentage was 61%. Based on the results obtained, it can be concluded that the results of the examination of bilirubin levels in alcohol consumers in Pohuwato Timur Village, Pohuwato Regency are more dominant with abnormal or high levels compared to normal bilirubin levels.

scholarly journals Impact of Contract Farming on Economic Status of the Farmers Practicing Contract Farming

2019 ◽  
Vol 7 (2) ◽  
pp. 39-46
Author(s):  
N Harish
Keyword(s):  
Sample Size ◽  
Economic Impact ◽  
Random Sampling ◽  
Economic Status ◽  
Simple Random Sampling ◽  
Rural District ◽  
Economic Indicators ◽  
Sampling Techniques ◽  
Contract Farming ◽  
Karnataka State

This article focused on the economic impact of contract farming on respondents who are involved in contract farming. The various economic indicators of impact on contract framers are discussed. The study was conducted in two districts of Karnataka state viz., Bangalore Rural and Tumakuru. Two taluks each from each district, Tumakuru and Gubbi taluks from Tumakuru district and Nelamangala and Doddaballapura taluks from Bangalore Rural district were selected. Total three crops were selected based on simple random sampling techniques; the sample size was Gherkin 35, Tomato 35, Watermelon 10 and non-contract farmers 20 from each taluks of two districts.

scholarly journals Efficiency of Adaptive Cluster Sampling for Estimating Plant Disease Incidence

2010 ◽  
Vol 100 (7) ◽  
pp. 663-670 ◽  
Author(s):  
P. S. Ojiambo ◽  
H. Scherm
Keyword(s):  
Sample Size ◽  
Random Sampling ◽  
Disease Incidence ◽  
Simple Random Sampling ◽  
Cluster Sampling ◽  
Adaptive Cluster Sampling ◽  
Initial Sample ◽  
Animal Populations ◽  
Final Sample ◽  
Minimum Number

Conventional sampling designs such as simple random sampling (SRS) tend to be inefficient when assessing rare and highly clustered populations because most of the time is spent evaluating empty quadrats, leading to high error variances and high cost. In previous studies with rare plant and animal populations, adaptive cluster sampling, where sampling occurs preferentially in the neighborhood of quadrats in which the species of interest is detected during the sampling bout, has been shown to estimate population parameters with greater precision at an effort comparable to SRS. Here, we use computer simulations to evaluate the efficiency of adaptive cluster sampling for estimating low levels of disease incidence (0.1, 0.5, 1.0, and 5.0%) at various levels of aggregation of infected plants having variance-to-mean ratios (V/M) of ≈1, 3, 5, and 10. For each simulation, an initial sample size of 50, 100, and 150 quadrats was evaluated, and the condition to adapt neighborhood sampling (CA), i.e., the minimum number of infected plants per quadrat that triggers a switch from random sampling to sampling in neighboring quadrats, was varied from 1 to 4 (corresponding to 7.7 to 30.8% incidence of infected plants per quadrat). The simulations showed that cluster sampling was consistently more precise than SRS at a field-level disease incidence of 0.1 and 0.5%, especially when diseased plants were highly aggregated (V/M = 5 or 10) and when the most liberal condition to adapt (CA = 1) was used. One drawback of adaptive cluster sampling is that the final sample size is unknown at the beginning of the sampling bout because it depends on how often neighborhood sampling is triggered. In our simulations, the final sample size was close to the initial sample size for disease incidence up to 1.0%, especially when a more conservative condition to adapt (CA > 1) was used. For these conditions, the effect of disease aggregation was minor. In summary, both precision and the sample size required with adaptive cluster sampling responded similarly to disease incidence and aggregation, i.e., both were most favorable at the lowest disease incidence with the highest levels of clustering. However, whereas relative precision was optimized with the most liberal condition to adapt, the ratio of final to initial sample size was best for more conservative CA values, indicating a tradeoff. In our simulations, precision and final sample size were both simultaneously favorable for disease incidence of up to 1.0%, but only when infected plants were most aggregated (V/M = 10).

scholarly journals The relationship between job satisfaction and work performance of sub-district municipality administrators in the eastern region, Thailand

2021 ◽  
Vol 336 ◽  
pp. 09025
Author(s):  
Sakdipath Plikamin ◽  
Pongsatean Luengalongkot
Keyword(s):  
Job Satisfaction ◽  
Data Analysis ◽  
Sample Size ◽  
Random Sampling ◽  
Work Performance ◽  
Statistical Significance ◽  
Sampling Technique ◽  
Simple Random Sampling ◽  
Eastern Region ◽  
The Relationship

The purpose of this paper is to study the relationship between job satisfaction and work performance of sub- district municipality administrators in the eastern region. The population used in this research is the head and sub-head of sub-district municipality, which have offices in 7 provinces of the eastern region of Thailand, totally 531 people. The sample size consisted of 400 people. Simple random sampling technique was used to collect data. The instruments used for collecting data were questionnaires. In the data analysis, pear son product moment correlation was used to analyse the relationship between job satisfaction and work performance of sub- district municipality administrators in the eastern region by setting statistical significance at the level of 0.01. The results showed that there is a relationship between job satisfaction and work performance of sub- district municipality administrators in the eastern region.

scholarly journals Prevalence of gastrointestinal helminths in sheep raised in intermediary geographical region of Paraiba state, Brazil

2019 ◽  
Vol 26 ◽  
pp. 1-9
Author(s):  
José Gabriel Gonçalves Lins ◽  
Serginara David Rodrigues ◽  
Ana Valéria Mello de Souza Marques
Keyword(s):  
Sample Size ◽  
Random Sampling ◽  
Simple Random Sampling ◽  
Gastrointestinal Nematodes ◽  
Gastrointestinal Helminths ◽  
Faecal Samples ◽  
High Prevalence ◽  
Third Stage ◽  
Polyethylene Bags ◽  
Positive Animal

The objective of this study was to evaluate the prevalence of gastrointestinal nematodes (GIN) of sheep herds from twenty-three sheep farms spread in the Alto Sertão region of Paraíba state, Brazil. Sample size was obtained through a simple random sampling, which was determined from the total amount of sheep head of the microregion. It was collected 262 faecal samples directly from the rectum of the animals, conditioned in polyethylene bags previously identified and kept refrigerated until processing. Faecal egg counting was performed and cultures in pool of each farm were done separately. It was observed a prevalence of GN of 84.7% (222/262) to the evaluated sheep. Furthermore, it was noted the presence of unless one positive animal for helminths in 100.0% of sheep farms.  Among the 222 positive animals, 65.3% presented EPG<1000, 15.8% EPG among 1000-2000 and 18.9% presented EPG>2000. Recovered third stage larvae showed that the most prevalent nematode was Haemonchus sp. (79.6%), followed by Trichostrongylus sp. (13.8%), Oesophagostomum sp. (3.6%), Strongyloides sp. (2.4%) e Bunostomum sp. (0.6%). Sheep herd from the Alto Sertão region of Paraíba state presents a high prevalence of GIN.

E-Learning Adoption: An Empirical Study on App Based Learning Among Lower Primary Class Students in Karnataka Region

2020 ◽  
Vol 17 (9) ◽  
pp. 4350-4353
Author(s):  
M. Rizwana ◽  
Padmalini Singh ◽  
Raveendra a ◽  
Rohith Hallur
Keyword(s):  
Academic Performance ◽  
Empirical Study ◽  
Sample Size ◽  
Random Sampling ◽  
Research Work ◽  
Sampling Technique ◽  
Simple Random Sampling ◽  
The Core ◽  
Academic Activities ◽  
E Learning

The present research work essentially targets the audience who are using App based learning across Karnataka region. The core aim of the study is to identify the factors that influence the lower primary class students to opt for app based learning. The study has examined how well the students have adopted and are using the application in their day to day academic activities. By employing simple random sampling technique, a sample size of 54 respondents who are using app based learning were selected. The overall results showed that the respondents are highly satisfied with the app based learning and it has confirmed that the app based learning has helped the users enhance their academic performance.

scholarly journals Ratio Estimators Using Coefficient of Variation and Coefficient of Correlation

2014 ◽  
Vol 8 (5) ◽  
pp. 70 ◽  
Author(s):  
Prayad Sangngam
Keyword(s):  
Sample Size ◽  
Coefficient Of Variation ◽  
Random Sampling ◽  
Simple Random Sampling ◽  
Stratified Random Sampling ◽  
Size Estimation ◽  
Auxiliary Variables ◽  
Coefficient Of Correlation ◽  
Ratio Estimators ◽  
Mean Square Errors

This paper introduces ratio estimators of the population mean using the coefficient of variation of  study variable and auxiliary variables together with the coefficient of correlation between the study and auxiliary variables under simple random sampling and stratified random sampling. These ratio estimators are almost unbiased. The mean square errors of the estimators and their estimators are given. Sample size estimation in both sampling designs are presented. An optimal sample size allocation in stratified random sampling is also suggested. Based on theoretical study, it can be shown that these ratio estimators have smaller MSE than the unbiased estimators. Moreover, the empirical study indicates that these ratio estimators have smallest MSE compared to the existing ones.

Sign in / Sign up

Export Citation Format

Share Document