scholarly journals Correlation Analysis of Roughness Surface Height Distribution Parameters and Maximum Mises Stress

2021 ◽  
Author(s):  
Duo Yang ◽  
Qibo Wang ◽  
Jinyuan Tang ◽  
Fujia Xia ◽  
Wei Zhou ◽  
...  
Keyword(s):  
Correlation Analysis ◽  
Rough Surface ◽  
Contact Stress ◽  
Extreme Values ◽  
Combination Method ◽  
Particle Swarm Algorithm ◽  
Height Distribution ◽  
Roughness Surface ◽  
Distribution Parameters ◽  
The Relationship

Abstract Roughness surfaces contact analysis is an advanced research topic in interface design. The 3D rough surface amplitude distribution characterized by height distribution parameters(Sq (root mean square), Ssk (skewness), Sku (kurtosis)) has a great influence on the extreme value and distribution of the interface contact stress. However, the relationship between height distribution parameters and surface maximum mises stress (σmax) is still unclear and lacks of in-depth study. With the assistance of roughness surface reconstruction and contact stress algorithm proposed by the research group, σmax under a large sample was calculated and used as the data support for correlation analysis. Through BP neural network, global sensitivity qualitative (Morris) and quantitative (Sobol) analysis methods, the relationship between Sq, Ssk, Sku and σmax under different loads is studied. Based on complete polynomial and permutation combination method, the optimal correlation model between height distribution parameters and σmax was established, and particle swarm algorithm was introduced to analyze σmax extreme values under different Sq. The results show that: (1) Under different loads, the order about height distribution parameters influence on surface contact stress is: Sq> Ssk > Sku, and as the load increases, the influence of Ssk and Sku gradually decreases. (2) In different roughness surfaces, the influence of Ssk and Sku on the contact performance is significantly full of discrepancy. The research results provide reference and technical support for active design of rough surface microstructure to improved contact performance.

scholarly journals A Comparative Study on Asperity Peak Modeling Methods

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Wei Zhou ◽  
Daiyan Zhao ◽  
Jinyuan Tang ◽  
Jun Yi
Keyword(s):  
Rough Surface ◽  
Surface Profile ◽  
Statistical Characteristics ◽  
Height Distribution ◽  
Statistical Distributions ◽  
Spectral Moment ◽  
Correlation Pattern ◽  
Modeling Methods ◽  
Distribution Parameters ◽  
Moment Approach

AbstractThe peak identification scheme based method (three-point definition) and the spectral moments based method (spectral moment approach) are both widely used for asperity peak modeling in tribology. To discover the differences between the two methods, a great number of rough surface profile samples with various statistical distributions are first randomly generated using FFT. Then the distribution parameters of asperity peaks are calculated for the generated samples with both methods. The obtained results are compared and verified by experiment. The variation rules of the differences between the two methods with statistical characteristics of rough surfaces are investigated. To explain for the discovered differences, the assumptions by spectral moment approach that the joint distribution of surface height, slope and curvature is normal and that the height distribution of asperities is Gaussian, are examined. The results show that it is unreasonable to assume a joint normal distribution without inspecting the correlation pattern of [z], [z′] and [z′′], and that the height distribution of asperities is not exactly Gaussian before correlation length of rough surface increases to a certain extent, 20 for instance.

scholarly journals A Comparative Study on Asperity Peak Modeling Methods

2020 ◽  
Author(s):  
Wei Zhou ◽  
Jin-Yuan Tang ◽  
Jun Yi
Keyword(s):  
Rough Surface ◽  
Surface Profile ◽  
Statistical Characteristics ◽  
Height Distribution ◽  
Statistical Distributions ◽  
Spectral Moment ◽  
Correlation Pattern ◽  
Modeling Methods ◽  
Distribution Parameters ◽  
Moment Approach

Abstract The peak identification scheme based method (three-point definition) and the spectral moments based method (spectral moment approach) are both widely used for asperity peak modeling in tribology. To discover the differences between the two methods, a great number of rough surface profile samples with various statistical distributions are first randomly generated using FFT. Then the distribution parameters of asperity peaks are calculated for the generated samples with both methods. The obtained results are compared and verified by experiment. The variation rules of the differences between the two methods with statistical characteristics of rough surfaces are investigated. To explain for the discovered differences, the assumptions by spectral moment approach that the joint distribution of surface height, slope and curvature is normal and that the height distribution of asperities is Gaussian, are examined. The results show that it is unreasonable to assume a joint normal distribution without inspecting the correlation pattern of [z], [z′] and [z′′], and that the height distribution of asperities is not exactly Gaussian before correlation length of rough surface increases to a certain extent, 20 for instance.

Analysis of Maximum Expiratory Flow Volume Curves Using Canonical Correlation Analysis

1985 ◽  
Vol 24 (02) ◽  
pp. 91-100 ◽  
Author(s):  
W. van Pelt ◽  
Ph. H. Quanjer ◽  
M. E. Wise ◽  
E. van der Burg ◽  
R. van der Lende
Keyword(s):  
Correlation Analysis ◽  
Canonical Correlation Analysis ◽  
Canonical Correlation ◽  
Flow Volume ◽  
Non Linear ◽  
Maximum Expiratory Flow ◽  
Expiratory Flow ◽  
Relationship Of ◽  
The Relationship ◽  
Age And Sex

SummaryAs part of a population study on chronic lung disease in the Netherlands, an investigation is made of the relationship of both age and sex with indices describing the maximum expiratory flow-volume (MEFV) curve. To determine the relationship, non-linear canonical correlation was used as realized in the computer program CANALS, a combination of ordinary canonical correlation analysis (CCA) and non-linear transformations of the variables. This method enhances the generality of the relationship to be found and has the advantage of showing the relative importance of categories or ranges within a variable with respect to that relationship. The above is exemplified by describing the relationship of age and sex with variables concerning respiratory symptoms and smoking habits. The analysis of age and sex with MEFV curve indices shows that non-linear canonical correlation analysis is an efficient tool in analysing size and shape of the MEFV curve and can be used to derive parameters concerning the whole curve.

THE EFFECT OF TRADE RECEIVABLES ON THE LIQUIDITY OF THE COMPANY PT. GRAHA TUMARIMA, CITY OF SUKABUMI

2020 ◽  
Author(s):  
endang naryono
Keyword(s):  
Correlation Analysis ◽  
Hypothesis Testing ◽  
Sampling Technique ◽  
Strong Relationship ◽  
T Test ◽  
Financial Statement ◽  
Positive Meaning ◽  
The Relationship ◽  
Purposive Sample ◽  
Analysis Determination

This study examines the influence of receivables on liquidity at PT. Graha Tumarima. Sukabumi City for 5 years, with a sampling technique using a purposive sample in the form of financial statement data from 2010 to 2014 using a table of trade receivables and company liquidity. In this study, researchers refer to the theory of Bambang Riyanto (2008: 94) as the connecting theory of the title. This study aims to determine whether there is a relationship and influence between receivables and liquidity at PT. Graha Tumarima. The research design uses the method of exposing the facto, the method of data collection aims to test the hypothesis by using correlation analysis, determination, regression and hypothesis testing with t-test. The results of this study show the influence of receivables on liquidity is shown by the value of r = 0.888, meaning that receivables have a very strong relationship to liquidity. The nature of the relationship is positive, meaning that if the value of cooperative credit is higher the liquidity will be higher. Conversely, if the value of receivables decreases, liquidity will decrease. The magnitude of the influence of receivables on liquidity is shown by the value of R Square / Determination Coefficient of 0.789 or 78.9% thus the receivables have an effect of 78.9% on cooperative liquidity. Hypothesis testing uses the t test, that t arithmetic = 3.347 while t table = 3.182 means t arithmetic> t table. Means that Ho is rejected and Ha is accepted. There is an influence between the receivables on liquidity at PT. Graha Tumarima, Sukabumi City

Absorption, Wicking and Drying Characteristics of Compression Garments

2015 ◽  
Vol 10 (3) ◽  
pp. 155892501501000 ◽  
Author(s):  
Canan Saricam
Keyword(s):  
Correlation Analysis ◽  
T Test ◽  
Test Analysis ◽  
Drying Characteristics ◽  
Compression Garments ◽  
Production Parameters ◽  
The Relationship

This paper discusses the influence of the production parameters on the moisture related comfort characteristics of the compression garments that differ according to the tension applied during the production and elastane count. Correlation analysis, two sided independent t-test analysis and ANOVA tests were applied to analyze the relationship between the production parameters and comfort characteristics which are absorption, vertical and transfer wicking and drying. It was found that tension and elastane composition affect the comfort characteristics by changing the porosity, thickness and the pathways within the fabric.

POWER LAW AND STRETCHED EXPONENTIAL EFFECTS OF EXTREME EVENTS IN CHINESE STOCK MARKETS

2010 ◽  
Vol 09 (02) ◽  
pp. 203-217 ◽  
Author(s):  
XIAOJUN ZHAO ◽  
PENGJIAN SHANG ◽  
YULEI PANG
Keyword(s):  
Correlation Analysis ◽  
Power Law ◽  
Extreme Events ◽  
Stock Markets ◽  
Cross Correlation ◽  
Extreme Values ◽  
Cumulative Distribution ◽  
Stretched Exponential ◽  
Cross Correlation Analysis ◽  
Chinese Stock Markets

This paper reports the statistics of extreme values and positions of extreme events in Chinese stock markets. An extreme event is defined as the event exceeding a certain threshold of normalized logarithmic return. Extreme values follow a piecewise function or a power law distribution determined by the threshold due to a crossover. Extreme positions are studied by return intervals of extreme events, and it is found that return intervals yield a stretched exponential function. According to correlation analysis, extreme values and return intervals are weakly correlated and the correlation decreases with increasing threshold. No long-term cross-correlation exists by using the detrended cross-correlation analysis (DCCA) method. We successfully introduce a modification specific to the correlation and derive the joint cumulative distribution of extreme values and return intervals at 95% confidence level.

scholarly journals Correlating Capsaicinoid Levels and Physicochemical Proper-ties of Kimchi and Its Perceived Spiciness

Foods ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 86
Author(s):  
So-Ra Yoon ◽  
Yun-Mi Dang ◽  
Su-Yeon Kim ◽  
Su-Yeon You ◽  
Mina K. Kim ◽  
...  
Keyword(s):  
Correlation Analysis ◽  
Physicochemical Properties ◽  
Correlation Coefficient ◽  
Partial Correlation ◽  
Sugar Content ◽  
Amino Acid Content ◽  
Titratable Acidity ◽  
Free Sugar ◽  
Partial Correlation Analysis ◽  
The Relationship

Capsaicinoid content, among other factors, affects the perception of spiciness of commercial kimchi. Here, we investigated whether the physicochemical properties of kimchi affect the spicy taste of capsaicinoids perceived by the tasting. High-performance liquid chromatography (HPLC) was used to evaluate the capsaicinoid content (mg/kg) of thirteen types of commercial kimchi. The physicochemical properties such as pH, titratable acidity, salinity, free sugar content, and free amino acid content were evaluated, and the spicy strength grade was determined by selected panel to analyze the correlation between these properties. Panels were trained for 48 h prior to actual evaluation by panel leaders trained for over 1000 h according to the SpectrumTM method. Partial correlation analysis was performed to examine other candidate parameters that interfere with the sensory evaluation of spiciness and capsaicinoid content. To express the specific variance after eliminating the effects of other variables, partial correlations were used to estimate the relationships between two variables. We observed a strong correlation between spiciness intensity ratings and capsaicinoid content, with a Pearson’s correlation coefficient of 0.78 at p ≤ 0.001. However, other specific variables may have influenced the relationship between spiciness intensity and total capsaicinoid content. Partial correlation analysis indicated that the free sugar content most strongly affected the relationship between spiciness intensity and capsaicinoid content, showing the largest first-order partial correlation coefficient (rxy/z: 0.091, p ≤ 0.01).

Hubungan antara Penilaian Pembelajaran dengan Tingkah Laku Pegawai Agama dalam Usaha Dakwah kepada Odha di Malaysia

2016 ◽  
Vol 1 (1) ◽  
pp. 27-42
Author(s):  
Hazlin Kadir @ Shahar ◽  
Razaleigh Muhamat @ Kawangit ◽  
Rosmawati Mohamad Rasit ◽  
Badlihisham Mohd Nasir
Keyword(s):  
Correlation Analysis ◽  
Quantitative Methods ◽  
Pearson Correlation ◽  
People Living With Hiv ◽  
Strong Positive Correlation ◽  
Learning Evaluation ◽  
Pearson Correlation Analysis ◽  
Training Programmes ◽  
The Relationship ◽  
Hiv Aids

This article examines the relationship between learning and behavioural evaluation among religious officers in Malaysia after attending the Manual on HIV/AIDS in Islam Training Programmes organized by the Islamic Development Department of Malaysia (JAKIM). The training programmes were implemented to deliver the most accurate and the latest information on HIV / AIDS as well as to train religious officers in Malaysia to address the issues among Muslims. The training programmes apply the theoretical and practical activities where participants had the opportunity to carry out outreach activities with People Living with HIV / AIDS (ODHA). Quantitative methods through questionnaires were used to obtain data. A total of 350 religious officers who had attended the training programmes were selected as respondents by simple random sampling technique. Pearson correlation analysis was conducted to determine the relationship between the learning and behavioural evaluation. The results of the Pearson correlation analysis found that there was a significant relationship between learning evaluation in terms of the information obtained from programmes’ contents and behaviour evaluation with r = 0.489 and sig = 0.000 (p <0.05) at the medium positive range.. While the relationship between learning evaluation in terms of the information obtained from outreach activities with behavioural evaluation showed a strong positive correlation with the strength values obtained were r = 0.539 and sig = 0.000 (p <0.05). This analysis shows that the information acquired through the training program Manual Islam and HIV / AIDS has been successful in changing the behaviour of religious officers’ awareness in terms of the role of dakwah to ODHA. ABSTRAK Artikel ini bertujuan melihat hubungan antara penilaian pembelajaran dengan penilaian tingkah laku dalam kalangan Pegawai Agama di Malaysia setelah mengikuti Program Latihan Manual Islam dan HIV/AIDS anjuran Jabatan Kemajuan Islam Malaysia (JAKIM). Program latihan ini dilaksanakan untuk menyampaikan maklumat yang tepat serta informasi terkini isu HIV/AIDS di samping melatih Pegawai-pegawai Agama di Malaysia untuk menangani isu tersebut dalam kalangan umat Islam. Program latihan ini berbentuk teori dan praktikal di mana peserta program berpeluang melaksanakan dakwah secara temu seru (outreach) dengan Orang Yang Hidup dengan HIV/AIDS (ODHA) secara langsung. Kaedah kuantitatif melalui soal selidik telah digunakan untuk memperoleh data. Seramai 350 orang Pegawai Agama yang telah mengikuti program latihan ini dipilih sebagai responden melalui teknik pensampelan rawak mudah. Analisis korelasi Pearson dijalankan bagi mengenal pasti hubungan di antara penilaian pembelajaran dengan penilaian tingkah laku peserta yang mengikuti Program Latihan Manual Islam dan HIV/AIDS. Hasil analisis ujian korelasi Pearson tersebut mendapati bahawa terdapat hubungan yang signifikan di antara penilaian pembelajaran dari segi maklumat yang diperoleh daripada kandungan program dengan penilaian tingkah laku dengan nilai r = 0.489 dan sig = 0.000 (p<0.05). Kekuatan hubungan ialah positif sederhana. Manakala hubungan antara penilaian pembelajaran dari segi maklumat yang diperoleh daripada program temu seru dengan penilaian tingkah laku pula menunjukkan kekuatan hubungan positif kuat dengan nilai yang diperoleh ialah r = 0.539 dan sig = 0.000 (p<0.05). Analisis ini menunjukkan bahawa pembelajaran yang diperoleh melalui program latihan Manual Islam dan HIV/AIDS ini telah berjaya mengubah tingkah laku Pegawai Agama dari segi kesedaran peranan berdakwah kepada ODHA.

Utilizarea teoriei valorilor extreme în climatologie

2019 ◽  
Author(s):  
Valentin Raileanu ◽  
Keyword(s):  
Maximum Likelihood ◽  
Extreme Values ◽  
Probability Distributions ◽  
Simulated Data ◽  
Likelihood Estimation ◽  
R Software ◽  
Data Set ◽  
Data Format ◽  
Generalized Pareto ◽  
Distribution Parameters

The article briefly describes the history and fields of application of the theory of extreme values, including climatology. The data format, the Generalized Extreme Value (GEV) probability distributions with Bock Maxima, the Generalized Pareto (GP) distributions with Point of Threshold (POT) and the analysis methods are presented. Estimating the distribution parameters is done using the Maximum Likelihood Estimation (MLE) method. Free R software installation, the minimum set of required commands and the GUI in2extRemes graphical package are described. As an example, the results of the GEV analysis of a simulated data set in in2extRemes are presented.

Sign in / Sign up

Export Citation Format

Share Document