scholarly journals Estimating Cycling Aerodynamic Performance Using Anthropometric Measures

2020 ◽  
Vol 10 (23) ◽  
pp. 8635
Author(s):  
Raman Garimella ◽  
Thomas Peeters ◽  
Eduardo Parrilla ◽  
Jordi Uriel ◽  
Seppe Sels ◽  
...  
Keyword(s):  
Drag Force ◽  
Joint Angle ◽  
Aerodynamic Drag ◽  
Linear Regression Analysis ◽  
3D Models ◽  
Frontal Area ◽  
Coefficient Of Determination ◽  
Anthropometric Measures ◽  
Aerodynamic Efficiency ◽  
Angle Data

Aerodynamic drag force and projected frontal area (A) are commonly used indicators of aerodynamic cycling efficiency. This study investigated the accuracy of estimating these quantities using easy-to-acquire anthropometric and pose measures. In the first part, computational fluid dynamics (CFD) drag force calculations and A (m2) values from photogrammetry methods were compared using predicted 3D cycling models for 10 male amateur cyclists. The shape of the 3D models was predicted using anthropometric measures. Subsequently, the models were reposed from a standing to a cycling pose using joint angle data from an optical motion capture (mocap) system. In the second part, a linear regression analysis was performed to predict A using 26 anthropometric measures combined with joint angle data from two sources (optical and inertial mocap, separately). Drag calculations were strongly correlated with benchmark projected frontal area (coefficient of determination R2 = 0.72). A can accurately be predicted using anthropometric data and joint angles from optical mocap (root mean square error (RMSE) = 0.037 m2) or inertial mocap (RMSE = 0.032 m2). This study showed that aerodynamic efficiency can be predicted using anthropometric and joint angle data from commercially available, inexpensive posture tracking methods. The practical relevance for cyclists is to quantify and train posture during cycling for improving aerodynamic efficiency and hence performance.

A Novel Training Bike and Camera System to Evaluate Pose of Cyclists

2020 ◽  
Author(s):  
Raman Garimella ◽  
Koen Beyers ◽  
Thomas Peeters ◽  
Stijn Verwulgen ◽  
Seppe Sels ◽  
...  
Keyword(s):  
Inertial Sensors ◽  
Sagittal Plane ◽  
Aerodynamic Drag ◽  
Linear Regression Analysis ◽  
The Body ◽  
Frontal Area ◽  
Motion Sensors ◽  
Joint Angles ◽  
Camera System ◽  
Flexion Extension

Abstract Aerodynamic drag force can account for up to 90% of the opposing force experienced by a cyclist. Therefore, aerodynamic testing and efficiency is a priority in cycling. An inexpensive method to optimize performance is required. In this study, we evaluate a novel indoor setup as a tool for aerodynamic pose training. The setup consists of a bike, indoor home trainer, camera, and wearable inertial motion sensors. A camera calculates frontal area of the cyclist and the trainer varies resistance to the cyclist by using this as an input. To guide a cyclist to assume an optimal pose, joint angles of the body are an objective metric. To track joint angles, two methods were evaluated: optical (RGB camera for the two-dimensional angles in sagittal plane of 6 joints), and inertial sensors (wearable sensors for three-dimensional angles of 13 joints). One (1) male amateur cyclist was instructed to recreate certain static and dynamic poses on the bike. The inertial sensors provide excellent results (absolute error = 0.28°) for knee joint. Based on linear regression analysis, frontal area can be best predicted (correlation > 0.4) by chest anterior/posterior tilt, pelvis left/right rotation, neck flexion/extension, chest left/right rotation, and chest left/right lateral tilt (p < 0.01).

Methodology for the Estimation of the Aerodynamic Drag Parameters of Cyclists

2019 ◽  
Author(s):  
Alejandra Polanco ◽  
Juan Fuentes ◽  
Sebastián Porras ◽  
Daniel Castiblanco ◽  
Julián Uribe ◽  
...  
Keyword(s):  
Drag Force ◽  
Aerodynamic Drag ◽  
Cycling Performance ◽  
Experimental Methodology ◽  
Frontal Area ◽  
Relevant Effect ◽  
Aerodynamic Parameters ◽  
Resistive Forces ◽  
Drag Area

Abstract The aerodynamic drag force has a relevant effect on cycling performance since it is one of the major resistive forces acting on the bicycle. For this reason, this paper presents the development of an experimental methodology to estimate the aerodynamic parameters of a bicycle-cyclist set. The methodology combines outdoor measurements to estimate the drag area with indoor measurements to measure the projected frontal area. The methodology was implemented to quantify the effect of posture in the aerodynamic parameters of a group of cyclists. The tests were performed to characterize the drag parameters associated with three postures defined by the position of the grip on the handlebar: tops, hoods, and drops. Significant differences in the aerodynamic parameters were found for the postures studied through the proposed methodology. The posture variation led to reductions of up to 11.8% in the drag area of the cyclists when passing from tops to drops posture. The results obtained are in agreement with the literature indicating that the implementation of the methodology is feasible for the estimation of the aerodynamic parameters in cycling.

Parametric Study of Drag Force on a Formula Student Electric Race Car Using CFD

2014 ◽  
Vol 575 ◽  
pp. 300-305 ◽  
Author(s):  
Lalit Patidar ◽  
Sri Ramya Bhamidipati
Keyword(s):  
Drag Force ◽  
Fuel Economy ◽  
Aerodynamic Drag ◽  
Pressure Coefficient ◽  
Substantial Reduction ◽  
Frontal Area ◽  
Test Case ◽  
Electric Cars ◽  
Race Car ◽  
Set Up

Aerodynamic drag plays an important role in fuel economy of the vehicle especially for electric cars directly affecting the range. The objective of Aerodynamics subsystem of IIT Bombay racing team is to predict and minimize drag force on the Formula student electric race car thereby improving the performance. A standard generic car body known as Ahmed body is taken to set up simulation parameters in FLUENT by validating a test case against the experimental data available in literature. Variation and dependence of drag force on parameters such as frontal area, distribution of pressure coefficient and pressure loss in wake region is studied numerically. Comparison is made between Formula Student 2013 car Evo2 and newly designed car Evo3 for coming season of Formula Student 2014. A substantial reduction in drag force of 18.8% is achieved which can be attributed to lower frontal area and streamlined bodyworks design. Energy consumption of the vehicle for endurance race is reduced by 11.5 % improving the fuel economy.

IMPACT OF AIS AND STRESSED OUT AN EMPLOYEES TO THEIR PERFORMANCE AT PT EFRATA RETAILINDO

2019 ◽  
Vol 5 (1) ◽  
pp. 22-30
Author(s):  
Wiwit Ayu Retno Sari ◽  
Suhendro Suhendro ◽  
R. Riana Dewi
Keyword(s):  
Information Systems ◽  
Work Stress ◽  
Quantitative Research ◽  
Linear Regression Analysis ◽  
Accounting Information ◽  
Multiple Linear Regression Analysis ◽  
Primary Data ◽  
Coefficient Of Determination ◽  
Accounting Information System ◽  
Accounting Information Systems

This research aims to test the influence of accounting information system and work stress on performance of employees of PT Efrata Retailindo. The type of research used in this research is quantitative research. The source of the data in the research is primary data. The population in this study are all employees of PT Efrata Retailindo totalling 47 people. Sampling techniques in the study using a purposive sample. While the data collection method used is to use the questionnaire to all employees of PT Efrata Retailindo. Data analysis techniques using multiple linear regression analysis. Based on the results of the study it can be concluded that work stress had no effect on performance of employees of PT Efrata Retailindo, while information systems accounting effect on the performance of the employees of PT Efrata Retailindo. The value of the coefficient of determination (R2) amounting to 0.106. This indicates that variansi on a variable performance practice undertaken by the company PT Efrata Retailindo of 10.6% can be explained by work stress variables and accounting information systems, while the remaining 89.4% explained by other factors outside the researched.

PENGARUH KEPEMIMPINAN TRANSFORMASIONAL, KEPUASAN KERJA, KEPERCAYAAN KEPADA PEMIMPIN TERHADAP KETERIKATAN KERJA KARYAWAN PADA PT. BALI BIJAKSANA NUSA DUA – BALI

2019 ◽  
Vol 14 (4) ◽  
pp. 2455
Author(s):  
I Putu Dharmawan Pradhana ◽  
Putu Nova Kusuma Hendra
Keyword(s):  
Job Satisfaction ◽  
Transformational Leadership ◽  
Employee Engagement ◽  
Regression Coefficient ◽  
Linear Regression Analysis ◽  
Simple Random Sampling ◽  
Multiple Linear Regression Analysis ◽  
Coefficient Of Determination ◽  
Positive Effects ◽  
Trust In Leaders

The purpose of this study was to determine the effect of transformational leadership, job satisfaction, trust in leaders on employee engagement at PT.Bali Bijaksana Nusa Dua – Bali. The number of samples in this study were 75 employees with a simple random sampling method. Data collection used questionnaire. The data analysis technique used is the classical assumption test, multiple linear regression analysis, t-test, F-test and test coefficient of determination. The results of the study show that there are positive and partial positive effects of transformational leadership, job satisfaction, and trust in leaders in increasing employee engagement at PT. Bali Bijaksana Nusa Dua – Bali. The results showed that the transformational leadership regression coefficient (X1) was 0.268 with a value that meant that each increase in transformational leadership variables could increase employee engagement at PT. Bali Bijaksana Nusa Dua – Bali. Job satisfaction regression coefficient (X2) is equal to 0.303, which means that every increase in job satisfaction variables can increase employee engagement at PT. Bali Bijaksana Nusa Dua – Bali. Regression coefficient value to leader (X3) is equal to 0.256, which means that every increase in the trust variable in the leader can increase employee engagement at PT. Bali Bijaksana Nusa Dua – Bali. As  the results of the determination coefficient of 0.657, its means that 65.7% can explain the model or influence of each variable on work engagement, while the rest (100% -65.7% = 34,3%) is explained by other reasons outside research model.

The Effect of Investments and Risk Based Capital (RBC) of Tabarru Funds on Company (Case Study of Sharia Insurance in Indonesia for 2014-2019)

2020 ◽  
Vol 8 (1) ◽  
pp. 87-97
Author(s):  
Nana Diana ◽  
Tati Apriani
Keyword(s):  
Life Insurance ◽  
Statistical Tests ◽  
Linear Regression Analysis ◽  
Sampling Technique ◽  
Multiple Linear Regression Analysis ◽  
Insurance Companies ◽  
Coefficient Of Determination ◽  
Verification Method ◽  
Investment Returns ◽  
The Government

This study aims to examine the influence of investment returns and Risk Based Capital (RBC) Tabarru Funds to the profit of sharia life insurance in Indonesia from 2014-2019. This study The type of this research is quantitative research with descriptive verification as a method. This research method uses descriptive verification method with quantitative approach. The data used in this study were sourced from the financial statements of Islamic life insurance companies in Indonesia for the 2014-2019 period. Then the data obtained were analyzed using multiple linear regression analysis and hypothesis testing consisting of t test and f test with the help of SPSS 21 software. The sampling technique uses non probability sampling with purposive sampling technique. Based on the results of the study it can be seen that the development of investment returns on Sharia Life Insurance in Indonesia has fluctuated and even suffered losses. While the development of Risk Based Capital (RBC) has increased and decreased but overall above 120% as determined by the government. Likewise, the profits earned in each year fluctuate. The results of statistical tests show that investment results partially have a positive effect on profit and Risk Based Capital (RBC) of Tabarru funds partially has a negative effect on profit. Simultaneously investment return and Risk Based Capital (RBC) affect on profit. In addition, the results of the coefficient of determination (R2) were obtained which obtained a value of 81%. This shows that the variable investment returns and Risk Based Capital (RBC) can affect earnings by 81% and the remaining 19% is influenced by other variables not used in this study.

FRAUD CONFIRMATION, CLIENT SATISFACTION AND CLIENT LOYALTY

2019 ◽  
Vol 1 (1) ◽  
pp. 39
Author(s):  
Ngurah Pandji Mertha Agung Durya
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Client Satisfaction ◽  
Audit Quality ◽  
Hypothesis Test ◽  
Linear Regression Analysis ◽  
Quality Attributes ◽  
Path Model ◽  
Coefficient Of Determination ◽  
The Government

<p>This study aims to find evidence, the influence of Audit Quality Attributes, Client Satisfaction and Client Loyalty, which are moderated by Fraud Confirmation. The research was conducted at the BKM, a community-based organization, formed by the Government, through the <em>Kotaku</em> Program. The research used Regression statistical analysis and conducted a hypothesis test. Regression analysis used includes Simple Linear Regression Analysis, Multiple Regression Analysis, and MRA Regression Analysis, and Path Model Linear Regression Analysis. This study also pays attention to the calculation of the coefficient of determination to give an idea of the ability of the model in explaining the phenomenon of Client Satisfaction and Client Loyalty. The result that both partially and simultaneously, Audit Quality Attributes, Fraud Confirmation affected Client Satisfaction and Loyalty. The research also succeeded in proving that Client Satisfaction mediates the effect of Audit Quality Attributes on Client Loyalty, but failed to provide empirical evidence, that the Fraud Confirmation moderated the effect of Audit Quality Attributes on Client Satisfaction and Loyalty. Contribution to audit practices, where it is important to realize Client Satisfaction through Audit Quality Attributes and Fraud Confirmation, especially in situations where Fraud acts are suspected.</p>

PENGARUH CITRA MEREK DAN KUALITAS BENIH TERHADAP KEPUTUSAN PEMBELIAN PADA PT.PRABU ARGO MANDIRI (Studi Kasus Penjualan Benih Tomat Merk Maya di Purwkarta)

2017 ◽  
Vol 6 (2) ◽  
Author(s):  
Ahmad Iskandar
Keyword(s):  
Product Quality ◽  
Brand Image ◽  
Hypothesis Test ◽  
Descriptive Analysis ◽  
Linear Regression Analysis ◽  
Coefficient Of Determination ◽  
Decision Variable ◽  
Purchasing Decisions ◽  
Business World

In the era of globalization, the competition in the business world becomes very tight. Companies vying to be able to continue to compete and survive in the business world. Each consumer must have had the expectation that the products they buy are able to provide satisfaction for them to be making purchasing decisions. Consumer purchasing decisions of companies to seeds virtual brand still low due to the brand image and quality of seeds that are still unsatisfactory.This study aims to determine the responses of respondents regarding brand image, product quality, purchasing decisions and how big an impact on the brand image itself against purchase decisions on the PT. Prabu Argo Mandiri Bandung and how much influence the quality of products on the purchase decision.The method by which the samples is Simple Random Sampling consists of 80 respondents. The method of analysis in this research using descriptive analysis and verification which is composed of multiple linear regression analysis. Product moment correlation analysis, and the coefficient of determination used to measure the level of influence of brand image and product quality on purchasing decisions.The results based on descriptive analysis of brand image variable is in good enough category, variable quality of the product is in the unfavorable category, and the purchase decision variable is in the unfavorable category. The results based on correlation test showed that the brand image is partially significant effect on purchasing decisions by 68% and the product quality is partially significant effect on purchasing decisions by 13%. Hypothesis test results suggested that the increased purchasing decisions partially and simultaneously influence through brand image and product quality.

PENGARUH KUALITAS PELAYANAN, HARGA DAN CITRA MEREK TERHADAP KEPUASAN MAHASISWA

2019 ◽  
Vol 8 (2) ◽  
pp. 104
Author(s):  
Titim Nurlia
Keyword(s):  
Service Quality ◽  
Student Satisfaction ◽  
Significant Influence ◽  
Brand Image ◽  
Linear Regression Analysis ◽  
Research Result ◽  
Coefficient Of Determination ◽  
F Test ◽  
Fierce Competition ◽  
Students Satisfaction

<p>Highly competition requires university to be more sensitive to the interest students as one of stakeholders. Polytechnic LP3I Jakarta Campus Cimone has many competitors amid the dynamics of increasingly fierce competition of higher education. This research aims to analyze the effect of Service quality, Price and Brand Image of Students Satisfaction. A theory used in research is based on opinion from Andriyani, Suwandi Mananeke &amp; Taroreh, Fatriansyah. There is an effect between Service Quality, Price and Brand Image to Customer Satisfaction. This research use a quantitative method by distributing a questionnaire. The amount of population are 408 students and the sample is 80 people by Slovin formulas. Based on research result using linear regression analysis multiple SPSS version 20 indicated that: The independent variable Service Quality, Price and Brand Image jointly tested by F test proved positive and significant influence on the Student Satisfaction and the magnitude of the effect seen from the coefficient of determination (R<sub>2</sub>) was 41,8 %. To test the hypothesis of the use F test and t test. While price do not have effect significant influence on students satisfaction.</p><p> </p><strong>Keywords:</strong> service quality, price, brand image, student’s satisfaction

PENGARUH KEPUASAN KERJA DAN KOMPETENSI TERHADAP KINERJA KARYAWAN PERUSAHAAN AIRNAV INDONESIA

2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Nuridin Nurudin ◽  
Yuli Anggraini S
Keyword(s):  
Random Sampling ◽  
Employee Performance ◽  
Hypothesis Test ◽  
Linear Regression Analysis ◽  
Work Satisfaction ◽  
Sampling Technique ◽  
Multiple Linear Regression Analysis ◽  
Coefficient Of Determination ◽  
Main Determinants ◽  
A Company

<em>One of the main determinants that influence the success rate of a company is employee performance. Efforts to improve employee performance, including by pay attention to work satisfaction and competence. This research was aimed to determine the effect of work satisfaction and competence to employees performance of AirNav Indonesia company. The population in this research were employess of AirNav Indonesia company at financial department were amounted to 387 people. The sample in this study were amounted to 80 employees using Slovin formula with random sampling technique. The method of data technique which used in the research was using multiple linear regression analysis, coefficient of determination and hypothesis test. Before being analyzed the instrument test was carried out. The results of this research can be known that work satisfaction and competence have a positive and significant influence to employees performance of AirNav Indonesia company.</em>

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