scholarly journals Asymptotic formulae for estimating statistical significance in particle physics analyses

2021 ◽  
Author(s):  
Matthew Joseph Basso
Keyword(s):  
Closed Form ◽  
Particle Physics ◽  
Statistical Tests ◽  
Statistical Significance ◽  
Measurement Model ◽  
Asymptotic Approximations ◽  
Computationally Efficient ◽  
Measurement Models ◽  
Asymptotic Formulae ◽  
Simplifying Assumptions

Abstract Within the framework of likelihood-based statistical tests for particle physics measurements, we derive expressions for estimating the statistical significance of discovery using the asymptotic approximations of Wilks and Wald for four measurement models. These models include arbitrary numbers of signal regions, control regions, and Gaussian constraints. We extend our expressions to use the representative or "Asimov" dataset proposed by Cowan et al. such that they are made data-free. While many of the expressions are complicated and often involve solving systems of coupled, multivariate equations, we show these expressions reduce to closed-form results under simplifying assumptions. We also validate the predicted significances using toy-based data in select cases and show the asymptotic formulae to be more computationally efficient than the toy-based approach. Additionally, different parameters within each measurement model are varied in order to understand their effect on the predicted significance.

scholarly journals Measuring the Refined Theory of Individual Values in 49 Cultural Groups: Psychometrics of the Revised Portrait Value Questionnaire

Assessment ◽  
2021 ◽  
pp. 107319112199876
Author(s):  
Shalom H. Schwartz ◽  
Jan Cieciuch
Keyword(s):  
Measurement Model ◽  
Scaling Analysis ◽  
Refined Theory ◽  
Cultural Groups ◽  
Individual Values ◽  
Internal Reliability ◽  
Measurement Models ◽  
Circular Structure ◽  
Almost All ◽  
Portrait Value Questionnaire

Researchers around the world are applying the recently revised Portrait Value Questionnaire (PVQ-RR) to measure the 19 values in Schwartz’s refined values theory. We assessed the internal reliability, circular structure, measurement model, and measurement invariance of values measured by this questionnaire across 49 cultural groups ( N = 53,472) and 32 language versions. The PVQ-RR reliably measured 15 of the 19 values in the vast majority of groups and two others in most groups. The fit of the theory-based measurement models supported the differentiation of almost all values in every cultural group. Almost all values were measured invariantly across groups at the configural and metric level. A multidimensional scaling analysis revealed that the PVQ-RR perfectly reproduced the theorized order of the 19 values around the circle across groups. The current study established the PVQ-RR as a sound instrument to measure and to compare the hierarchies and correlates of values across cultures.

scholarly journals A Bayesian solution to the Behrens–Fisher problem

2021 ◽  
Vol 115 (4) ◽  
Author(s):  
Fco. Javier Girón ◽  
Carmen del Castillo
Keyword(s):  
Closed Form ◽  
Hierarchical Model ◽  
Bayes Factor ◽  
Bayes Factors ◽  
Simple Solution ◽  
Asymptotic Approximations ◽  
Normal Distributions ◽  
Fisher Distribution ◽  
Leibler Divergence

AbstractA simple solution to the Behrens–Fisher problem based on Bayes factors is presented, and its relation with the Behrens–Fisher distribution is explored. The construction of the Bayes factor is based on a simple hierarchical model, and has a closed form based on the densities of general Behrens–Fisher distributions. Simple asymptotic approximations of the Bayes factor, which are functions of the Kullback–Leibler divergence between normal distributions, are given, and it is also proved to be consistent. Some examples and comparisons are also presented.

scholarly journals Design of Cut off-Frequency Fixing Filters by Error Compensation of MAXFLAT FIR Filters

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 553
Author(s):  
Daewon Chung ◽  
Woon Cho ◽  
Inyeob Jeong ◽  
Joonhyeon Jeon
Keyword(s):  
Closed Form ◽  
Error Compensation ◽  
Finite Impulse Response ◽  
Cutoff Frequency ◽  
Closed Form Solution ◽  
Form Solution ◽  
Fir Filters ◽  
Frequency Error ◽  
Computationally Efficient ◽  
Filter Type

Maximally-flat (MAXFLAT) finite impulse response (FIR) filters often face a problem of the cutoff-frequency error due to approximation of the desired frequency response by some closed-form solution. So far, there have been plenty of efforts to design such a filter with an arbitrarily specified cut off-frequency, but this filter type requires extensive computation and is not MAXFLAT anymore. Thus, a computationally efficient and effective design is needed for highly accurate filters with desired frequency characteristics. This paper describes a new method for designing cutoff-frequency-fixing FIR filters through the cutoff-frequency error compensation of MAXFLAT FIR filters. The proposed method provides a closed-form Chebyshev polynomial containing a cutoff-error compensation function, which can characterize the “cutoff-error-free” filters in terms of the degree of flatness for a given order of filter and cut off-frequency. This method also allows a computationally efficient and accurate formula to directly determine the degree of flatness, so that this filter type has a flat magnitude characteristic both in the passband and the stopband. The remarkable effectiveness of the proposed method in design efficiency and accuracy is clearly demonstrated through various examples, indicating that the cutoff-fixing filters exhibit amplitude distortion error of less than 10−14 and no cut off-frequency error. This new approach is shown to provide significant advantages over the previous works in design flexibility and accuracy.

Aspects of project learning in construction: a socio-technical model

2014 ◽  
Vol 14 (2) ◽  
pp. 229-244 ◽  
Author(s):  
Ali Mohammed Alashwal ◽  
Hamzah Abdul-Rahman
Keyword(s):  
Latent Variable ◽  
Construction Projects ◽  
Team Building ◽  
Principal Component ◽  
Measurement Model ◽  
Survey Method ◽  
Path Modeling ◽  
Content Type ◽  
Measurement Models ◽  
Project Learning

Purpose – The purpose of this paper is to determine the measurement constructs of learning within construction projects' milieu. The literature indicated some mechanisms of learning in projects under four aspects, namely knowledge sharing, knowledge creation, team action to learn, and learning support. The empirical study attempts to verify whether intra-project learning can be measured through these aspects. Design/methodology/approach – The study used a survey method to collect the data from 36 mega-sized building projects in Malaysia. In total, 203 questionnaires were collected from professionals working in the sites of these projects. The data were analysed using principal component analysis (PCA) to determine the constructs of intra-project learning. Partial least squares-path modeling was used then to confirm the results of PCA and determine the contribution of each construct to intra-project learning. Findings – The results affirmed two constructs of intra-project learning, named, social and technical and each consisted of four indicators of learning. Originality/value – The paper emphasized the socio-technical perspective of learning and contributed to developing a hierarchical measurement model of learning in construction project. A project manager can propose new initiatives in response to the new perspective of learning for team building and continuous development. Lastly, the paper provides a comprehensive presentation of how to estimate the hierarchical measurement models of project learning as a latent variable.

scholarly journals Model Calibration for a Rigid Hexapod-Based End-Effector with Integrated Force Sensors

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3537
Author(s):  
Christian Friedrich ◽  
Steffen Ihlenfeldt
Keyword(s):  
Parameter Identification ◽  
Degrees Of Freedom ◽  
Force Measurement ◽  
Experimental Studies ◽  
Measurement Model ◽  
Calibration Procedure ◽  
Force Sensors ◽  
End Effector ◽  
Measurement Models ◽  
Fast Procedure

Integrated single-axis force sensors allow an accurate and cost-efficient force measurement in 6 degrees of freedom for hexapod structures and kinematics. Depending on the sensor placement, the measurement is affected by internal forces that need to be compensated for by a measurement model. Since the parameters of the model can change during machine usage, a fast and easy calibration procedure is requested. This work studies parameter identification procedures for force measurement models on the example of a rigid hexapod-based end-effector. First, measurement and identification models are presented and parameter sensitivities are analysed. Next, two excitation strategies are applied and discussed: identification from quasi-static poses and identification from accelerated continuous trajectories. Both poses and trajectories are optimized by different criteria and evaluated in comparison. Finally, the procedures are validated by experimental studies with reference payloads. In conclusion, both strategies allow accurate parameter identification within a fast procedure in an operational machine state.

Uncertainty quantification for aerodynamic pressure probes, using adaptive quasi-Monte Carlo

2021 ◽  
Author(s):  
Alexandros Christos Chasoglou ◽  
Panagiotis Tsirikoglou ◽  
Anestis I Kalfas ◽  
Reza S Abhari
Keyword(s):  
Monte Carlo ◽  
Measurement Model ◽  
Fast Response ◽  
Two Stage ◽  
Detailed Measurement ◽  
Underlying Distribution ◽  
Factors Affecting ◽  
Quasi Monte Carlo ◽  
Measurement Models ◽  
Aerodynamic Pressure

Abstract In the present study, an adaptive randomized Quasi Monte Carlo methodology is presented, combining Stein’s two-stage adaptive scheme and Low Discrepancy Sobol sequences. The method is used for the propagation and calculation of uncertainties related to aerodynamic pneumatic probes and high frequency fast response aerodynamic probes (FRAP). The proposed methodology allows the fast and accurate, in a probabilistic sense, calculation of uncertainties, ensuring that the total number of Monte Carlo (MC) trials is kept low based on the desired numerical accuracy. Thus, this method is well-suited for aerodynamic pressure probes, where multiple points are evaluated in their calibration space. Complete and detailed measurement models are presented for both a pneumatic probe and FRAP. The models are segregated in sub-problems allowing the evaluation and inspection of intermediate steps of MC in a transparent manner, also enabling the calculation of the relative contributions of the elemental uncertainties on the measured quantities. Various, commonly used sampling techniques for MC simulation and different adaptive MC schemes are compared, using both theoretical toy distributions and actual examples from aerodynamic probes' measurement models. The robustness of Stein's two-stage scheme is demonstrated even in cases when signiffcant deviation from normality is observed in the underlying distribution of the output of the MC. With regards to FRAP, two issues related to piezo-resistive sensors are addressed, namely temperature dependent pressure hysteresis and temporal sensor drift, and their uncertainties are accounted for in the measurement model. These effects are the most dominant factors, affecting all flow quantities' uncertainties, with signiffcance that varies mainly with Mach and operating temperature. This work highlights the need to construct accurate and detailed measurement models for aerodynamic probes, that otherwise will result in signiffcant underestimation (in most cases in excess of 50%) of the final uncertainties.

scholarly journals Use of a Simple Anthropometric Measurement to Identify Low-Birth-Weight Infants in Enugu, Nigeria

2018 ◽  
Vol 5 ◽  
pp. 2333794X1878817
Author(s):  
Ndubuisi Kennedy Chukwudi ◽  
Huldah Ijeoma Nwokeukwu ◽  
Gilbert Nwadiakanma Adimorah
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Statistical Tests ◽  
Statistical Significance ◽  
Linear Regression Analysis ◽  
Cutoff Point ◽  
Chest Circumference ◽  
Anthropometric Measurement ◽  
Suitable Alternative ◽  
Study Population

Background. This prospective study was conducted to identify a suitable alternative to birth weight and establish its cutoff point to facilitate the identification of low-birth-weight (LBW) infants in Enugu, Southeast Nigeria. Methods. The study involved newborn babies within the first 48 hours of life. Five anthropometric measurements (head, chest, mid-arm and calf circumferences, as well as abdominal girth) were taken using a tape measure while supine length was measured with an aluminum infantometer. Birth weight was also recorded. Linear regression analysis was done to identify the measurement with the highest coefficient of determination with birth weight while its cutoff point was defined using a receiver operating characteristic curve. Standard statistical tests were used to determine the statistical significance of the findings. Results. The LBW prevalence for the study population was 21.41%. Chest circumference had the highest R2 value of 0.83 for the general study population and 0.72 for the LBW infants. The identified cutoff point for chest circumference is ⩽30 cm. Conclusion. Chest circumference is the best alternative to birth weight in identifying LBW babies within the first 48 hours of life in this environment.

Customer experience management in medical tourism (case study: Iranian hospital’s medical tourists)

2021 ◽  
Vol 13 (1) ◽  
pp. 198-226
Author(s):  
Hamed Dabaghi ◽  
Saeid Saieda Ardakani ◽  
Seyed Mohammad Tabataba’i-Nasab
Keyword(s):  
Medical Tourism ◽  
Statistical Tests ◽  
Statistical Significance ◽  
Data Gathering ◽  
Customer Experience ◽  
Research Literature ◽  
Content Type ◽  
Research Areas ◽  
Customer Experience Management ◽  
Data Saturation

Purpose The purpose of this paper is to focus on the emerging phenomenon of medical tourism in the context of Iran from a customer experience management perspective and benchmark of their judgment including positive or negative, of the experience they have achieved of the Iranian health (medical) experience (CE) and suggest scenarios for the improvement of the Iranian customer experience management (CEM). Design/methodology/approach The research methodologies and research methods that are used in this descriptive-analytical research are based on an inspection of the remarkable literature related to medical tourism and customer experience management. The data gathering instrument is a researcher-made questionnaire based on the variables in the conceptual model extracted from the research literature. The study was conducted from May to August 2019. The population cohort of this study was the foreign patients calling selected Iranian hospitals and the sampling method was a purposive and snowball sample of prospective medical tourists. As the study was conducted throughout Iran, some important hospitals in Iran were selected by stratified sampling Yang et al. (2020b). The sample size and data saturation were 500 participants Lv and Song (2019). The collected data using the questionnaire were analyzed by SPSS software and statistical tests. Findings According to the results, the customer experience management statistical significance in the task aspect is (p = 0.0523), in the mechanical aspect is (p = 0.0563), in the human aspect is (p = 0.0544). The study showed positive customer experience among the patients who had been treated in the Iranian hospitals. Originality/value There is a lack of study that focuses on medical tourism and customer experience management in Iran. Therefore, based on the results of this study, the experience of medical tourists in Iran proved to be positive and satisfying. As little research has been conducted in the area of customer experience management (CEM) in Iranian medical tourism, future researchers can use these valuable results precisely and in more detail to benchmark more accurately the customer experience in all areas of medical and health tourism and other research areas in different aspects of CEM in Iran.

Prediction of Bubbles, Crashes, and Antibubbles

2017 ◽  
Author(s):  
Didier Sornette
Keyword(s):  
Stock Market ◽  
Case Studies ◽  
Power Law ◽  
Statistical Tests ◽  
Statistical Significance ◽  
Large Market ◽  
Simple Power ◽  
Market Crashes ◽  
Successes And Failures

This chapter examines how to predict stock market crashes and other large market events as well as the limitations of forecasting, in particular in terms of the horizon of visibility and expected precision. Several case studies are presented in detail, with a careful count of successes and failures. After providing an overview of the nature of predictions, the chapter explains how to develop and interpret statistical tests of log-periodicity. It then considers the concept of an “antibubble,” using as an example the Japanese collapse from the beginning of 1990 to the present. It also describes the first guidelines for prediction, a hierarchy of prediction schemes that includes the simple power law, and the statistical significance of the forward predictions.

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