scholarly journals Steady-State Car-Following Time Gaps: An Empirical Study Using Naturalistic Driving Data

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Amara Loulizi ◽  
Youssef Bichiou ◽  
Hesham Rakha
Keyword(s):  
Steady State ◽  
Goodness Of Fit ◽  
Statistical Tests ◽  
Chi Square ◽  
Large Variability ◽  
Empirical Measures ◽  
Car Following ◽  
Access Road ◽  
Time Gap ◽  
Naturalistic Driving

The time gap is defined as the time difference between the rear of a vehicle and the front of its follower, which affects both safety and the saturation flow rate of a roadway segment. In this study, naturalistic driving data were examined to measure time gaps from seven different drivers in a car-following scenario within steady-state conditions. The measurements were taken from a 13-km section of a Dulles Airport access road in Washington, DC. In total, 168,053 time gap samples were obtained covering seven speed intervals. Analysis of the data revealed a large variation in time gaps within individual drivers’ driving data, with coefficients of variation as high as 63.8% observed for some drivers. Results also showed that the variability within drivers was more significant at speeds higher than 54 km/h. In addition, there was a large variability between drivers. At speeds above 108 km/h, minimum time gaps left by some drivers could be 1.6 times longer than those left by others. Several statistical distributions were used to fit the data of the seven drivers as well as the data for all drivers combined for each speed interval. The selected distributions passed the goodness-of-fit (Kolmogorov-Smirnov, Chi-square, and Anderson-Darling) criteria only when the number of samples was reduced. Data reduction was not performed randomly, but rather in a manner intended to maintain the same observed distribution when all the samples were used. It is therefore recommended that empirical measures of distributions be used in traffic microsimulation software rather than theoretically fit distributions obtained based on statistical tests. This will lead to better naturalistic traffic behavior simulations, resulting in more precise predicted measures of performance (travel time, fuel consumption, and gas emissions).

scholarly journals Visual Assessment vs. Statistical Goodness of Fit Tests for Identifying Parent Population

1988 ◽  
Vol 32 (7) ◽  
pp. 460-464
Author(s):  
Mari Berry ◽  
Brian Peacock ◽  
Bobbie Foote ◽  
Lawrence Leemis
Keyword(s):  
Goodness Of Fit ◽  
Statistical Tests ◽  
Visual Assessment ◽  
Discrete Distributions ◽  
Human Observer ◽  
Chi Square ◽  
Data Set ◽  
Goodness Of Fit Tests ◽  
Parent Distribution ◽  
Chi Square Test

Statistical tests are used to identify the parent distribution corresponding to a data set. A human observer looking at a histogram can also identify a probability distribution that models the parent distribution. The accuracy of a human observer was compared to the chi-square test for discrete data and the Kolmogorov-Smirnov and chi-square tests for continuous data. The human observer proved more accurate in identifying continuous distributions and the chi-square test proved to be superior in identifying discrete distributions. The effect of sample size and number of intervals in the histogram was included in the experimental design.

scholarly journals Factors of Purchase of Bread – Prospect to Regain the Market Share?

2016 ◽  
Vol 64 (3) ◽  
pp. 1067-1072 ◽  
Author(s):  
Ladislav Skořepa ◽  
Kamil Pícha
Keyword(s):  
Goodness Of Fit ◽  
Statistical Tests ◽  
P Value ◽  
Goodness Of Fit Test ◽  
Chi Square ◽  
Significance Level ◽  
Pearson Coefficient ◽  
The Family ◽  
Statistical Hypotheses ◽  
Buying Behaviour

The aim of the article is to assess the consumers’ buying behaviour and decision-making process when purchasing bread and to propose the ways of how to improve the position of bread in the market. 1601 properly filled questionnaires were used for the analysis. Results are presented under the form of frequencies of answers and statistical tests. The analysis included evaluation of statistical hypotheses about the independence (significance level α = 0.01) using the chi-square goodness of fit test and Pearson coefficient of contingency. The significance level was then compared with the value p-value, for p-value > α, the null hypothesis was not rejected. The most important factors of choosing bread are freshness, appearance habit and price. The importance of the price grows with the increasing age of respondents and decreases with the increasing income of questioned consumers. The importance of the brand, as well as the reference or recommendation from the family and friends slightly strengthens with the increasing income of the consumers. Most of the respondents make no difference between both (yeast and rye leaven) technologies of baking bread when making their buying decision. We cannot say, however, the preference to the rye leaven bread grows with the increasing age of respondents to the detriment of the yeast bread or vice versa.

Spectral Power Analysis of Drivers’ Gas Pedal Control during Steady-state Car-following on Freeways

2016 ◽  
Vol 60 (1) ◽  
pp. 729-733
Author(s):  
Fred Feng ◽  
Shan Bao ◽  
James Sayer ◽  
David LeBlanc
Keyword(s):  
Steady State ◽  
Time Series Data ◽  
Spectral Power ◽  
Cutoff Frequency ◽  
Frequency Component ◽  
Sensor Data ◽  
Series Data ◽  
Car Following ◽  
Naturalistic Driving ◽  
Lead Vehicle

This paper investigated the frequency characteristics of drivers’ gas pedal control in steady-state car-following on freeways by using vehicle sensor data from an existing naturalistic driving study. The main objectives were to examine the frequency range and distributions of a driver operating the gas pedal when following a lead vehicle, and whether the higher and lower frequency components of the gas pedal signal would vary when following a lead vehicle with varying distances. A total of 1,461 driving segments each with 90-seconds of steady-state freeway car-following were extracted from the naturalistic driving data. Fourier analysis was performed to convert the time series data of drivers’ gas pedal control to the frequency domain. The results show that during steady-state freeway car-following, the power of the gas pedal control peaks at around 0.033 Hz or 15 s per pedal movement (derived using the median of the peak frequency), and the upper limit of the frequency is around 0.94 Hz or 0.5 s per pedal movement (derived using the 95th percentile of the cutoff frequency). Further analysis showed that following a lead vehicle with smaller gap was associated with a larger proportion of the higher frequency component ( p < .001), and following a lead vehicle with larger gap was associated with a larger proportion of the lower frequency component ( p < .001). This suggests that the larger gap may allow the driver to relax control of the gas pedal with smoother operation. Potential applications of this paper include developing more realistic driver models that could be used in designing advanced driver assistance systems.

Comparação de testes coproparasitológicos em criadouro comercial de psitacídeos exóticos

2020 ◽  
Vol 3 (5) ◽  
pp. 100-107
Author(s):  
Marina Camargo de Sousa ◽  
◽  
Julia Ronzani Vial ◽  
Rodrigo Hidalgo Friciello Teixeira ◽  
Andrea Cristina Higa Nakaghi ◽  
...  
Keyword(s):  
Statistical Tests ◽  
Companion Animals ◽  
Clinical Importance ◽  
Breeding Site ◽  
Chi Square ◽  
Fecal Samples ◽  
Breeding Sites ◽  
Specificity And Sensitivity ◽  
Nematode Eggs ◽  
Commercial Breeding

Birds of the psittaciform order, composed by the Psittacidae and Loridae family have several characteristics making them more frequently kept as companion animals, promoting the increase of breeding sites in Brazil. The present study aimed to analyze the specificity and sensitivity of three different coproparasitological tests, Willis, Hoffman and Direto de feces, through statistical tests: Chi-Square and Kappa. 70 fecal samples of exotic parrots were collected from a commercial breeding site and these were submitted to the three tests, totaling 210 coproparasitological exams. Among the tests performed, 29,5% were positive for nematode eggs, cestodes and oocysts. Coproparasitological exams are inexpensive, have clinical importance, indicating the population of endoparasites and therapeutic treatments.

Analisis Faktor Determinan Pelaksanaan Inisiasi Menyusu Dini Oleh Bidan Di Rumah Sakit Umum Anutapura Palu

2018 ◽  
Vol 1 (1) ◽  
pp. 34
Author(s):  
Ni Nyoman Novita ◽  
Gusman Arsyad
Keyword(s):  
Emergency Room ◽  
Peer Support ◽  
Statistical Tests ◽  
Bivariate Analysis ◽  
P Value ◽  
Chi Square ◽  
Cross Sectional ◽  
Implementation Processes ◽  
Chi Square Test ◽  
The Government

Implementation of IMD in hospitals has decreased from the previous year and has not reached the target set by the government. Some IMD implementation processes have not been carried out according to applicable standards. So that babies do not get an IMD in accordance with existing SOPs. The purpose of this study was to determine the determinant factors associated with the implementation of the IMD by midwives in the Midwifery and Maternity Room Emergency Room (IGD) at the Anutapura General Hospital in Palu. This research method is analytical with cross sectional approach. The population of this study was that all midwives in the obstetrics emergency room and maternity room at Anutapura Palu Hospital were 37 respondents. The sample in this study is total sampling. The analysis used was univariate, and bivariate analysis using the chi square test with a confidence level of 95% (α = 0.05). The results of statistical tests on variable knowledge of midwives with the implementation of IMD p value: 0.018 (p value <0.05). APN training with the implementation of IMD p value: 0.697 (p value> 0.05). length of work with the implementation of IMD p value: 0.029 (p value <0.05). and peer support with the implementation of IMD p value: 0.007 (p value <0.05). Conclusions there is a relationship between knowledge, length of work, peer support with the implementation of the IMD, and training factors that have nothing to do with IMD implementation. The strongest factor in the relationship is peer support. It is recommended that the Anutarapura Palu Hospital be able to motivate midwives so that they can further enhance their role in the implementation and provide support to their colleagues so that the implementation of the IMD can be carried out in accordance with applicable standards.Keywords: Knowledge, APN Training, Duration of work, Implementation of IMD

Prediction of Haemoglobin Level by Some Probability Distribution

2020 ◽  
Vol 9 (1) ◽  
pp. 84-88
Author(s):  
Govinda Prasad Dhungana ◽  
Laxmi Prasad Sapkota
Keyword(s):  
Probability Distribution ◽  
Normal Distribution ◽  
Goodness Of Fit ◽  
Continuous Variable ◽  
Hemoglobin Level ◽  
Chi Square ◽  
Chi Square Test ◽  
Log Normal ◽  
Two Parameters ◽  
Best Fit

 Hemoglobin level is a continuous variable. So, it follows some theoretical probability distribution Normal, Log-normal, Gamma and Weibull distribution having two parameters. There is low variation in observed and expected frequency of Normal distribution in bar diagram. Similarly, calculated value of chi-square test (goodness of fit) is observed which is lower in Normal distribution. Furthermore, plot of PDFof Normal distribution covers larger area of histogram than all of other distribution. Hence Normal distribution is the best fit to predict the hemoglobin level in future.

HUBUNGAN ANTARA PENDIDIKAN DAN PEKERJAAN IBU HAMIL DENGAN PEMERIKSAAN KEHAMILAN DI PUSKESMAS MARIANA KECAMATAN BANYUASIN I KABUPATEN BANYUASIN TAHUN 2011

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Leny Leny
Keyword(s):  
Prenatal Care ◽  
Pregnant Women ◽  
Maternal Education ◽  
Statistical Tests ◽  
Univariate Analysis ◽  
World Health ◽  
P Value ◽  
Chi Square ◽  
Cross Sectional ◽  
Health Organization

ABSTRACT Prenatal care is health care by health personnel to care the pregnant according to standards. Worlrd Health Organization (WHO) estimates more than 500.000 women die during pregnancy or childbirth. Maternal mortality in Indonesia is 307 per 100,000 live births. The quantity of pregnant women’s visit in Kabupaten Banyuasin in 2009 of 89.1%. The purpose of this study to determine the relationship between education and occupation with prenatal care at Puskesmas Mariana  Kecamatan Banyuasin I Kabupaten Banyuasin in 2011. This study uses analytic approach survey by Cross Sectional methods, the population are 1.946 pregnant women and the samples as many as 332 people. The results of univariate analysis study of pregnant women who are higher education as much as 45.2%, and  low maternal education as much as 54.8%. In pregnant women who work of 43.4%, and pregnant women who do not work for 56.6%. From the results of bivariate analysis and Chi-Square statistical tests found a significant association between education of pregnant women with prenatal care with P Value = 0.000, and there was a significant association between occupation of pregnant women with prenatal care with P Value = 0.000. Can be concluded that there is a relationship between education and occupation of pregnant women with prenatal care. Expected to health workers to provide counseling on the importance of prenatal care in pregnant women and expected future studies may explore again the factors associated with prenatal care with the different variables.   ABSTRAK Pemeriksaan kehamilan adalah pelayanan kesehatan oleh tenaga kesehatan untuk memeriksakan ibu hamil sesuai standar. World Health Organization (WHO) memperkirakan lebih dari 500.000 ibu pertahunnya meninggal saat hamil atau bersalin. AKI di Indonesia 307 per 100.000 kelahiran hidup. Jumlah kunjungan ibu hamil di Kabupaten Banyuasin tahun 2009 sebesar 89,1%. Tujuan penelitian ini untuk mengetahui hubungan antara pendidikan dan pekerjaan dengan pemeriksaan kehamilan di Puskesmas Mariana Kecamatan Banyuasin I Kabupaten Banyuasin tahun  2011. Penelitian ini menggunakan metode survey analitik dengan pendekatan Cross Sectional, populasi ibu hamil dengan jumlah 1.946 orang dan jumlah sampel sebanyak 332 orang. Hasil penelitian Analisa Univariat adalah ibu hamil yang pendidikan tinggi sebanyak 45,2%, dan pendidikan rendah ibu hamil sebanyak 54,8%. Pada variabel pekerjaan ibu hamil yang bekerja sebesar 43,4%, dan ibu hamil yang tidak bekerja sebesar 56,6%. Dari hasil analisa bivariat dan uji statistik Chi-Square  didapatkan hubungan yang bermakna antara pendidikan ibu hamil dengan pemeriksaan kehamilan dengan  P Value = 0,000, dan ada hubungan yang bermakna antara pekerjaan ibu hamil dengan pemeriksaan kehamilan dengan P Value = 0,000. Dapat disimpulkan bahwa ada hubungan antara pendidikan dan pekerjaan ibu hamil dengan pemeriksaan kehamilan. Diharapkan kepada petugas kesehatan agar dapat memberikan penyuluhan tentang pentingnya pemeriksaan pada ibu hamil dan diharapkan penelitian yang akan datang dapat menggali lagi faktor-faktor yang berhubungan dengan pemeriksaan kehamilan dengan variabel yang berbeda.

The ffs Allele Conditions Flower Stem Fasciation in Red Beet

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 527f-528
Author(s):  
I.L. Goldman
Keyword(s):  
Genetic Control ◽  
Inbred Line ◽  
Goodness Of Fit ◽  
Female Parent ◽  
Inbred Lines ◽  
Chi Square ◽  
Recessive Character ◽  
Variable Expression ◽  
Red Beet ◽  
Flower Stem

A fasciated flower stem character arose spontaneously during development of the red beet (Beta vulgaris L.) inbred line W411. The fasciated character is manifest by a flattened flower stem with petioles coalesced into a twisted, ribbonlike appearance. No fasciation is present in the vegetative stem or petioles. An inheritance study was conducted to determine the genetic control of flower stem fasciation. The inbred line W411 was used both as a male and female parent in crosses with four red beet inbred lines. Segregating progenies in both the BC1 and F2 generations were developed and scored for the fasciated flower stem character. Variable expression of the fasciated flower stem phenotype was observed in these progenies; however, the presence of flattened flower stems at the stem/hypocotyl junction was unequivocal. Chi-square goodness-of-fit tests in both the BC1 and F2 generations did not deviate significantly from expected ratios for a monogenic recessive character for each genetic background. No reciprocal differences were detected for any cross in this group of four inbred lines, which suggests the lack of maternal effect for the fasciated character. The symbol ffs is proposed to describe the genetic control of the fasciated flower stem phenotype.

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