scholarly journals Improvements of Rackwitz–Fiessler Method for Correlated Structural Reliability Analysis

2019 ◽  
Vol 17 (06) ◽  
pp. 1950077 ◽  
Author(s):  
Sheng-Tong Zhou ◽  
Qian Xiao ◽  
Jian-Min Zhou ◽  
Hong-Guang Li
Keyword(s):  
Structural Reliability ◽  
Pearson Correlation ◽  
Computational Cost ◽  
Transformation Process ◽  
Point Of View ◽  
Gaussian Copula ◽  
Normal Space ◽  
Copula Theory ◽  
Geometric Point ◽  
Nataf Transformation

Rackwitz–Fiessler (RF) method is well accepted as an efficient way to solve the uncorrelated non-Normal reliability problems by transforming original non-Normal variables into equivalent Normal variables based on the equivalent Normal conditions. However, this traditional RF method is often abandoned when correlated reliability problems are involved, because the point-by-point implementation property of equivalent Normal conditions makes the RF method hard to clearly describe the correlations of transformed variables. To this end, some improvements on the traditional RF method are presented from the isoprobabilistic transformation and copula theory viewpoints. First of all, the forward transformation process of RF method from the original space to the standard Normal space is interpreted as the isoprobabilistic transformation from the geometric point of view. This viewpoint makes us reasonably describe the stochastic dependence of transformed variables same as that in Nataf transformation (NATAF). Thus, a corresponding enhanced RF (EnRF) method is proposed to deal with the correlated reliability problems described by Pearson linear correlation. Further, we uncover the implicit Gaussian copula hypothesis of RF method according to the invariant theorem of copula and the strictly increasing isoprobabilistic transformation. Meanwhile, based on the copula-only rank correlations such as the Spearman and Kendall correlations, two improved RF (IRF) methods are introduced to overcome the potential pitfalls of Pearson correlation in EnRF. Later, taking NATAF as a reference, the computational cost and efficiency of above three proposed RF methods are also discussed in Hasofer–Lind reliability algorithm. Finally, four illustrative structure reliability examples are demonstrated to validate the availability and advantages of the new proposed RF methods.

scholarly journals Joint Modeling of Precipitation and Temperature Using Copula Theory for Current and Future Prediction under Climate Change Scenarios in Arid Lands (Case Study, Kerman Province, Iran)

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
T. Mesbahzadeh ◽  
M. M. Miglietta ◽  
M. Mirakbari ◽  
F. Soleimani Sardoo ◽  
M. Abdolhoseini
Keyword(s):  
Climate Change ◽  
Goodness Of Fit ◽  
Joint Modeling ◽  
Copula Function ◽  
Gaussian Copula ◽  
Climate Change Scenarios ◽  
Climatic Parameters ◽  
Goodness Of Fit Test ◽  
Copula Theory ◽  
Precipitation And Temperature

Precipitation and temperature are very important climatic parameters as their changes may affect life conditions. Therefore, predicting temporal trends of precipitation and temperature is very useful for societal and urban planning. In this research, in order to study the future trends in precipitation and temperature, we have applied scenarios of the fifth assessment report of IPCC. The results suggest that both parameters will be increasing in the studied area (Iran) in future. Since there is interdependence between these two climatic parameters, the independent analysis of the two fields will generate errors in the interpretation of model simulations. Therefore, in this study, copula theory was used for joint modeling of precipitation and temperature under climate change scenarios. By the joint distribution, we can find the structure of interdependence of precipitation and temperature in current and future under climate change conditions, which can assist in the risk assessment of extreme hydrological and meteorological events. Based on the results of goodness of fit test, the Frank copula function was selected for modeling of recorded and constructed data under RCP2.6 scenario and the Gaussian copula function was used for joint modeling of the constructed data under the RCP4.5 and RCP8.5 scenarios.

scholarly journals Laws of the iterated logarithm on covering graphs with groups of polynomial volume growth

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ryuya Namba
Keyword(s):  
Random Walks ◽  
Quadratic Forms ◽  
Volume Growth ◽  
Moderate Deviation ◽  
Point Of View ◽  
Iterated Logarithm ◽  
Large Numbers ◽  
Geometric Point ◽  
Rate Functions ◽  
The Given

AbstractModerate deviation principles (MDPs) for random walks on covering graphs with groups of polynomial volume growth are discussed in a geometric point of view. They deal with any intermediate spatial scalings between those of laws of large numbers and those of central limit theorems. The corresponding rate functions are given by quadratic forms determined by the Albanese metric associated with the given random walks. We apply MDPs to establish laws of the iterated logarithm on the covering graphs by characterizing the set of all limit points of the normalized random walks.

Dynamics of Multibody Systems: Generalized Mass Metric in Riemannian Velocity Space and Recursive Momentum Formulation

2007 ◽  
Author(s):  
Qiang Zhao ◽  
Hong Tao Wu
Keyword(s):  
Point Of View ◽  
Velocity Space ◽  
Motion Equations ◽  
Closed Loop Systems ◽  
Dynamics Of Multibody Systems ◽  
Operator Factorization ◽  
Geometric Point ◽  
Mass Tensor ◽  
Generalized Momentum ◽  
Serial Chains

This paper describes two aspects of multibody system (MBS) dynamics on a generalized mass metric in Riemannian velocity space and recursive momentum formulation. Firstly, we present a detailed expression of the Riemannian metric and operator factorization of a generalized mass tensor for the dynamics of general-topology rigid MBS. The derived expression allows a clearly understanding the components of the generalized mass tensor, which also constitute a metric of the Riemannian velocity space. It is being the fact that there does exist a common metric in Lagrange and recursive Newton-Euler dynamic equation, we can determine, from the Riemannian geometric point of view, that there is the equivalent relationship between the two approaches to a given MBS. Next, from the generalized momentum definition in the derivation of the Riemannian velocity metrics, recursive momentum equations of MBS dynamics are developed for progressively more complex systems: serial chains, topological trees, and closed-loop systems. Through the principle of impulse and momentum, a new method is proposed for reorienting and locating the MBS form a given initial orientation and location to desired final ones without needing to solve the motion equations.

scholarly journals Criteria for evaluating the competencies of the school counselor at the basic education stage from the point of view of school principals in the state of Khartoum: معايير تقويم كفايات المرشد المدرسي بمرحلة تعليم الاساس من وجهة نظر مدراء المدارس بولاية الخرطوم

2017 ◽  
Vol 1 (3) ◽  
Author(s):  
Ikhlas Hassan Sayyid Echriya ◽  
Reham Anwar Mohammed Hassan
Keyword(s):  
School Counselor ◽  
Basic Education ◽  
School Principals ◽  
Pearson Correlation ◽  
Statistical Significance ◽  
Correlation Equation ◽  
Significance Test ◽  
Point Of View ◽  
The Stability ◽  
Extension Process

The aim of this study was to investigate the criteria of evaluating the competencies of the school counselor in the basic education stage, from the point of view of the school principals in Khartoum State, to achieve the objectives of the study. The researchers prepared a questionnaire that was applied during the academic year 2014-2015 to a random sample of 20 managers in basic education Khartoum, a maritime locality, the questionnaire contains six criteria for evaluating the school's competencies: planning the extension process, implementing the extension process, designing the extension programs, effective communication skills, using the technique in the extension process, In order to ascertain the stability and validity of the questionnaire, by means of the Alpha Kronbach equation and to verify the persistence of the questionnaire by Pearson correlation equation for the questionnaire items in the overall degree of the questionnaire, the sincerity of the arbitrators was measured by presenting it to a number of curriculum experts and pedagogic and educational psychologists in different Sudanese universities. Statistical packages of social sciences (SPSS), and statistical methods used to analyze repetitive data: percentages, arithmetical averages, standard deviations, mono variance, applied statistical significance test (T) The results of the study were reached by a number of recommendations, the most important of which are the need to develop an integrated methodology and a clear job description. For the role of the educational guide, and the process of educational guidance of schools based on the academic procedures of higher education, the need to contribute sections of educational psychology in the quality models and procedures to control and follow up the implementation of strategic plans for the tasks of the school guide and evaluate, The number of educational counselors for the number of learners and the creation of the guiding environment.

scholarly journals Pentingnya Membangun Platform Kolaborasi Multi-Stakeholder sebagai Key Enabling Factor dalam Membangun Ekosistem Inovasi Industri 4.0 di Era New Normal

2021 ◽  
Vol 6 (1) ◽  
pp. 67
Author(s):  
Satrio Utomo ◽  
Agus Nugroho Harjono
Keyword(s):  
Industry 4.0 ◽  
Industrial Development ◽  
Industrial Revolution ◽  
Transformation Process ◽  
Point Of View ◽  
Industrial Transformation ◽  
Program Manager ◽  
National Priority ◽  
Industry Policy ◽  
Multi Stakeholder

Industry 4.0 is an era of technological disruption or industrial revolution 4.0 because it puts more emphasis on system automation and connectivity which will make the mobility of the industrial world movement and  job competition non-linear . The use of digital technology is one of the keys. Industry opportunities for industrial development 4.0 are an effort to increase industrial competitiveness, but many industries do not yet understand the concept and how to start the stages. One of the ways proposed as a policy in preparing industry 4.0 should be taken a multi-stakeholder collaborative approach to facilitate development, including gathering digital transformation initiatives so that limited resources can be optimal. As a form of soft industry policy, a platform organization is also needed as a sustainable program manager and provides technical facilities. From a technical point of view, it is necessary to prepare enabling technology that can be utilized by all actors in the cross-sectoral digital economy in an affordable manner. The Ecosystem Platform becomes a medium to be able to build synergy and collaborative across industries with all stakeholders in an effort to accelerate the transformation of industry 4.0 according to the national priority program of Making Indonesia 4.0. In line with that, coordination was carried out between parties in the industrial transformation 4.0 process, as well as building networks to develop positive cooperation, including government, academics or R&D, industry players / associations, technical providers, consultants and of course financial actors in accelerating the industrial transformation process 4.0.

scholarly journals Reasons for Lying in Kindergarten Children from the Kindergarten Teachers’ Point of View: A Comparative Study between Males and Females

2021 ◽  
Vol 32 (3) ◽  
pp. 58-70
Author(s):  
Sajlaa Faiq Hashem ◽  
Kalthoom Abd Aon Radam
Keyword(s):  
Pearson Correlation ◽  
T Test ◽  
Point Of View ◽  
Kindergarten Children ◽  
Males And Females ◽  
The Difference ◽  
The Individual ◽  
Teachers Perspectives ◽  
Academic Year ◽  
Concrete Reality

Lying is considered a dangerous tendency among children if it has become a habit. It results in many social problems, such as child’s loss of confidence, lack of others’ respect to him, and his lack of respect to the desired values ​​of the society, such as honesty and trust. Consequently, he will be led to a deviation when he becomes old; especially if the child’s socially unaccepted behavior has not been directed. The research, thus, aims to examine the causes of lying in the most important stage of children’s life; that is, between (4-6) years. Such an aim helps to know about the individual reasons of lying among males and females from teachers’ perspectives. To meet the objective of the study, a number of (128) children has been randomly selected from the children of the Kindergarten Department during the academic year 2019-2020, together with (28) she-teachers. In addition, a questionnaire has been designed for the purpose of discovering the reasons behind a child’s lying in the Kindergarten. The researchers have used many statistical means, such as: T-test for one sample and T-test for two independent samples, Pearson correlation coefficient, and Kay square to find the difference between home and kindergarten regarding reasons of lying. Results have shown that the fe(male) children in the kindergarten live in a social environment that lacks honesty; especially the case with male children. Moreover, female kindergarten children enjoy a wide imagination; which is characterized by being exaggerating, abundance,, creativity, and lack of adherence to concrete reality. The reasons to lie for kindergarten male children are higher than that of female’. 

NONLINEARITY AND LEAST SQUARES

CISM journal ◽  
1988 ◽  
Vol 42 (4) ◽  
pp. 321-330 ◽  
Author(s):  
P.J.G. Teunissen ◽  
E.H. Knickmeyer
Keyword(s):  
Least Squares ◽  
Covariance Structure ◽  
Point Of View ◽  
Helmert Transformation ◽  
Know How ◽  
Least Squares Estimators ◽  
Functional Relations ◽  
Geometric Point ◽  
Rotational Invariant ◽  
Almost All

Since almost all functional relations in our geodetic models are nonlinear, it is important, especially from a statistical inference point of view, to know how nonlinearity manifests itself at the various stages of an adjustment. In this paper particular attention is given to the effect of nonlinearity on the first two moments of least squares estimators. Expressions for the moments of least squares estimators of parameters, residuals and functions derived from parameters, are given. The measures of nonlinearity are discussed both from a statistical and differential geometric point of view. Finally, our results are applied to the 2D symmetric Helmert transformation with a rotational invariant covariance structure.

scholarly journals A teaching proposal for the study of Eigenvectors and Eigenvalues

2017 ◽  
Vol 7 (1) ◽  
pp. 100 ◽  
Author(s):  
María José Beltrán Meneu ◽  
Marina Murillo Arcila ◽  
Enrique Jordá Mora
Keyword(s):  
Rigid Body ◽  
Mathematical Thinking ◽  
Point Of View ◽  
Moment Of Inertia ◽  
Geometric Point ◽  
The Moment ◽  
Eigenvectors And Eigenvalues

In this work, we present a teaching proposal which emphasizes on visualization and physical applications in the study of eigenvectors and eigenvalues. These concepts are introduced using the notion of the moment of inertia of a rigid body and the GeoGebra software. The proposal was motivated after observing students’ difficulties when treating eigenvectors and eigenvalues from a geometric point of view. It was designed following a particular sequence of activities with the schema: exploration, introduction of concepts, structuring of knowledge and application, and considering the three worlds of mathematical thinking provided by Tall: embodied, symbolic and formal.

Sign in / Sign up

Export Citation Format

Share Document