cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Averages for Multivariate Random Vectors with Random Weights
Creators: name: Soltani, A.R.
name: Roozegar, Rasool
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: We consider a random weights average of n independent continuous random vectors X1, ..., Xn, where random weights are cuts of [0, 1] by an increasing sequence of the order statistics of a random sample from a uniform [0, 1]. We employ the multivariate Stieltjes transform and Watson [15] celebrated formula involving the multivariate B-spline functions for distributional identification of multivariate random weights averages. We show that certain classes of Dirichlet and random scale stable random vectors are random weightes averages.
description: REVSTAT-Statistical Journal, Vol. 18 No. 4 (2020): REVSTAT-Statistical Journal
Utilization of MRI in surgical decision making in the shoulder
Creators: name: Simon, Maciej J. K.
name: Regan, William D.
Publisher: name: BioMed Central
Year: 2022

description: Background The aim of this study is to evaluate both the utility of MRI scans and reports used in the current practice routine of shoulder surgeons and their surgical decision-making process. Methods Ninety-three shoulder-specialised orthopaedic surgeons of the Canadian Shoulder and Elbow Society (CSES) Orthopaedic Association were surveyed in 2020 anonymously online to help identify the use of MR-imaging and reports in managing shoulder disorders and surgical decision process. Results Thirty out of 93 (32.25%) CSES fellowship-trained orthopaedic surgeons participated. Respondents request MRI scans in about 55% of rotator cuff (RC) pathology and 48% of shoulder instability cases. Fifty percent of patients with potential RC pathology arrive with a completed MRI scan prior first orthopaedic consult. Their surgical decision is primarily based on patient history (45–55%) and physical examination (23–42%) followed by MRI scan review (2.6–18%), reading MRI reports (0–1.6%) or viewing other imaging (3–23%) depending on the shoulder disease. Ninety percent of surgeons would not decide on surgery in ambiguous cases unless the MR-images were personally reviewed. Respondents stated that shoulder MRI scans are ordered too frequently prior specialist visit as identified in more than 50% of cases depending on pathology. Conclusions The decision-making process for shoulder surgery depends on the underlying pathology and patient history. The results demonstrate that orthopaedic surgeons are comfortable reviewing shoulder MRI scans without necessarily reading the MRI report prior to a surgical decision. MRI scans are becoming an increasingly important part of surgical management in shoulder pathologies but should not be used without assessment of patient history and or physical examination.
Parameters Estimation for Constant-Stress Partially Accelerated Life Tests of Generalized Half-Logistic Distribution Based on Progressive Type-II Censoring
Creators: name: M. Almarashi, Abdullah
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: In product-life testing experiments, the accelerated life testing (ALT) is applied to reduce the time and cost of tests. We consider the constant-stress partially ALT model when the lifetime of units under normal conditions follow the generalized half-logistic lifetime distribution based on progressive Type-II censored schemes. The likelihood functions of the parameters are derived and solved to present the maximum likelihood estimators of the model parameters. The approximate and two bootstrap confidence intervals are also proposed. The performance of the different methods were measured and compared through Monte Carlo simulation study. Finally, the results of a numerical example are discussed.
description: REVSTAT-Statistical Journal, Vol. 18 No. 4 (2020): REVSTAT-Statistical Journal
Quantile Regression Model for Bounded Responses Based on the Exponential-Geometric Distribution
Creators: name: Jodrá, Pedro
name: Jiménez-Gamero, María Dolores
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: The paper first introduces a new two-parameter continuous probability distribution with bounded support from the extended exponential-geometric distribution. Closed-form expressions are given for the moments, moments of the order statistics and quantile function of the new law; it is also shown that the members of this family of distributions can be ordered in terms of the likelihood ratio order. The parameter estimation is carried out by the method of maximum likelihood and a closed-form expression is given for the Fisher information matrix, which is helpful for asymptotic inferences. Then, a new regression model is introduced by considering the proposed distribution, which is adequate for situations where the response variable is restricted to a bounded interval, as an alternative to the well-known beta regression model, among others. It relates the median response to a linear predictor through a link function. Extensions for other quantiles can be similarly performed. The suitability of this regression model is exemplified by means of a real data application.
description: REVSTAT-Statistical Journal, Vol. 18 No. 4 (2020): REVSTAT-Statistical Journal
Block Bootstrap Prediction Intervals for GARCH Processes
Creators: name: Hamiye Beyaztas, Beste
name: Beyaztas, Ufuk
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: In this paper, we propose a new resampling algorithm based on block bootstrap to obtain prediction intervals for future returns and volatilities of GARCH processes. The finite sample properties of the proposed methods are illustrated by an extensive simulation study and they are applied to Japan Yen (JPY) / U.S. dollar (USD) daily exchange rate data. Our results indicate that: (i) the proposed algorithm is a good competitor or even better and (ii) computationally more efficient than traditional method(s).
description: REVSTAT-Statistical Journal, Vol. 18 No. 4 (2020): REVSTAT-Statistical Journal
Bootstrap Prediction Interval for ARMA Models with Unknown Orders
Creators: name: Lu, Xingyu
name: Wang, Lihong
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: This paper aims to investigate the construction of the prediction intervals for ARMA (p, q) models with unknown orders. We present the bootstrap algorithms for the prediction intervals based on the bootstrap distribution of orders (p, q). The asymptotic properties of the intervals are also discussed. The Monte Carlo simulation studies show that the proposed algorithm significantly improves the coverage accuracy of the prediction interval compared to the methods using pre-estimated values of orders, especially when the sample size is small and the true model order is low.
description: REVSTAT-Statistical Journal, Vol. 18 No. 3 (2020): REVSTAT-Statistical Journal
Independence Characterization for Wishart and Kummer Random Matrices
Creators: name: Ko Lodziejek, Bartosz
name: Piliszek, Agnieszka
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: We generalize the following univariate characterization of the Kummer and Gamma distributions to the cone of symmetric positive definite matrices: let X and Y be independent, non-degenerate random variables valued in (0,∞), then U = Y /(1 +X) and V = X(1 + U) are independent if and only if X follows the Kummer distribution and Y follows the the Gamma distribution with appropriate parameters. We solve a related functional equation in the cone of symmetric positive definite matrices, which is our first main result and apply its solution to prove the characterization of Wishart and matrix-Kummer distributions, which is our second main result.
description: REVSTAT-Statistical Journal, Vol. 18 No. 3 (2020): REVSTAT-Statistical Journal
Kernel Hazard Rate Function Estimate for Associated and Left Truncated Data
Creators: name: Guessoum, Zohra
name: Tatachak, Abdelkader
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: Let {XN , N ≥ 1} be a sequence of strictly stationary associated random variables of interest, and {TN , N ≥ 1} be a sequence of random truncating variables assumed to be independent from {XN , N ≥ 1}. In this paper, we establish the strong uniform consistency with a rate of a kernel hazard rate function estimator, when the variable of interest is subject to random left truncation under association condition. Simulation results are also provided to evaluate the finite-sample performances of the proposed estimator.
description: REVSTAT-Statistical Journal, Vol. 18 No. 3 (2020): REVSTAT-Statistical Journal
Efficiency of the Principal Component Liu-Type Estimator in Logistic Regression
Creators: name: Wu, Jibo
name: Asar, Yasin
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: In this paper we propose a principal component Liu-type logistic estimator by combining the principal component logistic regression estimator and Liu-type logistic estimator to overcome the multicollinearity problem. The superiority of the new estimator over some related estimators are studied under the asymptotic mean squared error matrix. A Monte Carlo simulation experiment is designed to compare the performances of the estimators using mean squared error criterion. Finally, a conclusion section is presented.
description: REVSTAT-Statistical Journal, Vol. 18 No. 3 (2020): REVSTAT-Statistical Journal
Bayesian Criteria for Non-Zero Effects Detection Under Skew-Normal Search Model
Creators: name: Sadeghi, Sara
name: Talebi, Hooshang
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: Shirakura et al. [12] introduced search probability (SP) in order to compare search designs (SD). Afterwards, the SP-based and other related criteria were developed, all for the normal model. In the present study, we considered a general underlying skew-normal (SN) model and obtained new criteria in a simple explicit form using the Bayesian approach. These criteria are design[1]dependent and hence are able to rank SDs with respect to their search performance.
description: REVSTAT-Statistical Journal, Vol. 18 No. 3 (2020): REVSTAT-Statistical Journal
Minimum Distance Tests and Estimates Based on Ranks
Creators: name: Navrátil, Radim
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: It is well known that the least squares estimate in classical linear regression model is very sensitive to violation of the assumptions, in particular normality of model errors. That is why a lot of alternative estimates has been developed to overcome these shortcomings. Quite interesting class of such estimates is formed by R-estimates. They use only ranks of response variable instead of their actual value. The goal of this paper is to extend this class by another estimates and tests based only on ranks. First, we will introduce a new rank test in linear regression model. The test statistic is based on a certain minimum distance estimator, but unlike classical rank tests in regression it is not a simple linear rank statistic. Then, we will return back to estimates and generalize minimum distance estimates for various type of distances. We will show that in some situation these tests and estimates have greater power than the classical ones. Theoretical results will be accompanied by a simulation study to illustrate finite sample behavior of estimates and tests.
description: REVSTAT-Statistical Journal, Vol. 18 No. 3 (2020): REVSTAT-Statistical Journal
The Effects of Silicone Enclosure Colour on the Function of Optical Sensors
Creators: name: Frank, Garrett
name: Askari, Shahbaz
name: Raschdorf, Katharina
name: Khosravi, Sadra
name: Kwon, Brian K.
name: Shadgan, Babak
Publisher: name: Multidisciplinary Digital Publishing Institute
Year: 2022

description: The colour of the silicone enclosure of an implantable reflectance-based optical probe plays a critical role in sensor performance. Red-coloured probes that are highly reflective to near-infrared light have been found to increase photodetector power by a factor of 6 for wavelengths between 660 and 950 nm and triple the magnitude of measured cardiac pulsations compared to traditional black probes. The increase in photodetector power and cardiac pulsation magnitude is presumably due to increased spatial range resulting from a higher magnitude of superficial tissue scattering. Conversely, probes with highly absorbent colours such as black and blue result in more stable signals and are expected to have higher spatial resolution and depth of penetration.
Couple of Non Reduced Bias Generalized Means in Extreme Value Theory
Creators: name: Penalva, Helena
name: Gomes, M. Ivette
name: Caeiro, Frederico
name: Neves, M. Manuela
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: Lehmer’s mean-of-order p (Lp) generalizes the arithmetic mean, and Lp extreme value index (EVI)-estimators can be easily built, as a generalization of the classical Hill EVI-estimators. Apart from a reference to the asymptotic behaviour of this class of estimators, an asymptotic comparison, at optimal levels, of the members of such a class reveals that for the optimal (p, k) in the sense of minimal mean square error, with k the number of top order statistics involved in the estimation, they are able to overall outperform a recent and promising generalization of the Hill EVI-estimator, related to the power mean, also known as H¨older’s mean-of-order-p. A further comparison with other ‘classical’ non-reduced-bias estimators still reveals the competitiveness of this class of EVI-estimators.
description: REVSTAT-Statistical Journal, Vol. 18 No. 3 (2020): REVSTAT-Statistical Journal
A Structural Equation Modeling Approach to Territorial Competitiveness in Morocco
Creators: name: Otman ELMEZDEGHI
name: Mustapha ACHIBANE
Publisher: name: Zenodo
Year: 2024

description: This paper scrutinizes the efficacy of a novel Structural Equation Modeling (SEM) approach tailored to assess and enhance territorial competitiveness in Morocco. It encompasses a multidimensional analysis of demographic characteristics, territory attributes, innovation, industrialization, administrative structures, strategic surveillance, and stakeholder engagement. By constructing a SEM, the paper addresses the complex interplay between these elements and their collective impact on territorial management and competitiveness. Drawing from a robust qualitative analysis, the study validates the SEM against the intricate Moroccan socio-economic backdrop, demonstrating its utility in capturing the nuanced effects of governance and strategic initiatives on regional development. The proposed SEM serves as a versatile framework, offering policymakers and researchers a sophisticated tool for dissecting and advancing territorial intelligence applications. The study’s findings advocate for a paradigm shift towards data-driven governance models that can maneuver the challenges and harness the opportunities within the dynamic Moroccan territories.
Parametric Elliptical Regression Quantiles
Creators: name: Hlubinka, Daniel
name: Šiman, Miroslav
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: The article extends linear and nonlinear quantile regression to the case of vector responses by generalizing multivariate elliptical quantiles to a regression context. In particular, it introduces parametric elliptical quantile regression in a general nonlinear multivariate heteroscedastic framework and discusses, investigates, and illustrates the new method in some detail, including basic properties, various parametrizations, possible heteroscedastic patterns, related computational issues, model validation, and a real biometric data example. The method seems suitable for multiresponse regression models with symmetric errors, especially if the dimension of responses is less than ten and if the right parametrization of the model follows from the context.
description: REVSTAT-Statistical Journal, Vol. 18 No. 3 (2020): REVSTAT-Statistical Journal
Protocol for a scoping review of sepsis epidemiology
Creators: name: Wilcox, M. E.
name: Daou, Marietou
name: Dionne, Joanna C.
name: Dodek, Peter M.
name: Englesakis, Marina
name: Garland, Allan
name: Lauzon, Claire
name: Loubani, Osama
name: Rochwerg, Bram
name: Shankar-Hari, Manu
name: Thavorn, Kednapa
name: Tricco, Andrea C.
Publisher: name: BioMed Central
Year: 2022

description: Introduction Sepsis is a common, life-threatening syndrome of physiologic, pathologic, and biochemical abnormalities that are caused by infection and propagated by a dysregulated immune response. In 2017, the estimated annual incidence of sepsis around the world was 508 cases per 100,000 (95% confidence interval [CI], 422–612 cases per 100,000), however, reported incidence rates vary significantly by country. A scoping review will identify knowledge gaps by systematically investigating the incidence of sepsis. Methods and analysis This scoping review will be guided by the updated JBI (formerly Joanna Briggs Institute) methodology. We will search the following electronic databases: MEDLINE, EMBASE, CINAHL, and Cochrane Database of Systematic Reviews/Central Register of Controlled Trials. In addition, we will search websites of trial and study registries. We will review titles and abstracts of potentially eligible studies and then full-texts by two independent reviewers. We will include any study that is focused on the incidence of sepsis or septic shock in any population. Data will be abstracted independently using pre-piloted data extraction forms, and we will present results according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis Protocols Extension for Scoping Reviews. Ethics and dissemination The results of this review will be used to create a publicly available indexed and searchable electronic registry of existing sepsis research relating to incidence in neonates, children, and adults. With input from stakeholders, we will identify the implications of study findings for policy, practice, and research. Ethics approval was not required given this study reports on existing literature.
WHO-Leitlinien für Umgebungslärm für die Europäische Region
Creators: name: Wothge, Jördis
Publisher: name: My University
Year: 2019
Subjects: subject: Geräuschemission
subject: Lärmwirkung
subject: Gesundheitliche Auswirkungen
subject: Weltgesundheitsorganisation
subject: Umweltleitlinien
subject: Lärm

description: Die Weltgesundheitsorganisation hat im Oktober 2018 neue Leitlinien für Umgebungslärm für die Europäische Region veröffentlicht. Diese beinhalten quellenspezifische Empfehlungen für fünf unterschiedlichen Lärmquellen: Straßenverkehr, Schienenverkehr, Luftverkehr, Lärm von Windenergieanlagen und Lärm während der Ausübung von Freizeitaktivitäten. Für jede dieser Lärmquellen werden Leitlinienwerte für den ganztägigen Dauerschallpegel Lden und den Nachtzeitraum Lnight definiert sowie Empfehlungen für Lärmminderungsmaßnahmen benannt. Dieses Positionspapier beschreibt und bewertet die neuen WHO Leitlinien für Umgebungslärm fachlich und ordnet die Leitlinien anschließend insgesamt ein. Quelle: Bericht
description: Die Weltgesundheitsorganisation hat im Oktober 2018 neue Leitlinien für Umgebungslärm für die Europäische Region veröffentlicht. Diese beinhalten quellenspezifische Empfehlungen für fünf unterschiedlichen Lärmquellen: Straßenverkehr, Schienenverkehr, Luftverkehr, Lärm von Windenergieanlagen und Lärm während der Ausübung von Freizeitaktivitäten. Für jede dieser Lärmquellen werden Leitlinienwerte für den ganztägigen Dauerschallpegel Lden und den Nachtzeitraum Lnight definiert sowie Empfehlungen für Lärmminderungsmaßnahmen benannt.Dieses Positionspapier beschreibt und bewertet die neuen ⁠WHO⁠ Leitlinien für Umgebungslärm fachlich und ordnet die Leitlinien anschließend insgesamt ein.
On the correspondence between abstract dialectical frameworks and nonmonotonic conditional logics
Creators: name: Heyninck, Jesse
name: Kern-Isberner, Gabriele
name: Thimm, Matthias
name: Skiba, Kenneth
Publisher: name: TU Dortmund
Year: 2021
Subjects: subject: Abstract argumentation
subject: Abstract dialectical frameworks
subject: Non-monotonic logics
subject: Non-monotonic conditionals
subject: Conditional logics
subject: Non-monotonic reasoning
subject: Defeasible reasoning
subject: 004
subject: Nichtmonotone Logik
subject: Argumentation
subject: Dialektische Logik

description: The exact relationship between formal argumentation and nonmonotonic logics is a research topic that keeps on eluding researchers despite recent intensified efforts. We contribute to a deeper understanding of this relation by investigating characterizations of abstract dialectical frameworks in conditional logics for nonmonotonic reasoning. We first show that in general, there is a gap between argumentation and conditional semantics when applying several intuitive translations, but then prove that this gap can be closed when focusing on specific classes of translations.
description: Annals of mathematics and artificial intelligence;Bd 89. 2021, H. 10/11, S. 1075-1099
Advances in Wishart-Type Modelling of Channel Capacity
Creators: name: Ferreira, J.T.
name: Bekker, A.
name: Arashi, M.
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: This paper paves the way when the assumption of normality is challenged within the wireless communications systems arena. Innovative results pertaining to the distributions of quadratic forms and their associated eigenvalue density functions for the complex elliptical family are derived, which includes an original Rayleigh-type representation of channels. The presented analytical framework provides computationally convenient forms of these distributions. The results are applied to evaluate an important information-theoretic measure, namely channel capacity. Superior performance in terms of higher capacity of the wireless channel is obtained when considering the underlying complex matrix variate t distribution compared to the usual complex matrix variate normal assumption.
description: REVSTAT-Statistical Journal, Vol. 18 No. 3 (2020): REVSTAT-Statistical Journal
Effect of electrolytes on the thermal stability of α–chymotrypsinogen A at acid pH
Creators: name: Romero, Carmen M.
name: Beltrán, Yuver A.
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Biophysics
subject: Biochemistry
subject: 29999 Physical Sciences not elsewhere classified
subject: FOS: Physical sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Inorganic Chemistry

description: This study investigates the effect of electrolytes on the thermodynamic stability of the protein α-chymotrypsinogen A at acid pH. Protein thermal stability in water, buffers and aqueous solutions of (NH4)2SO4, NH4NO3, NaCl, KCl at pH 2.00, 3.00 and 3.50 was followed by ultraviolet-visible spectroscopy (UV-VIS) and differential scanning calorimetry (DSC). Thermodynamic parameters of denaturation of the protein in water and in the aqueous mixed solvents were obtained from thermal denaturation curves. The results suggest that the unfolding process is reversible process and is well represented by a two state model. All the electrolytes used in this study increase the conformational stability of the protein. The stabilising effect of the electrolytes used in this study increases with electrolyte concentration and is in accordance with the effect of anions and cations described for positively charged proteins, being ammonium sulphate the salt that exerts the largest stabilising effect on α-chymotrypsinogen A.
Estimation of Small Area Total with Randomized Data
Creators: name: Ahmed, Shakeel
name: Shabbir, Javid
name: Gupta, Sat
name: Coolen, Frank
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: In social surveys involving questions that are sensitive or personal in nature, respondents may not provide correct answers to certain questions asked by the interviewer. The impact of this nonresponse or inaccurate response becomes even more acute in the case of small area estimation (SAE) where we already have the problem of small sample size coming from the small area. To obtain a truthful response, we use randomized response techniques in each small area. We assume that a non-sensitive auxiliary variable, highly correlated with the study variable, is available. We use the word model in two senses — one in the context of population models, i.e. the relationship between the study variable and the auxiliary variable; and second, the scrambled response model. We focus on the problem of estimating small area total and examine its performance both theoretically and numerically.
description: REVSTAT-Statistical Journal, Vol. 18 No. 2 (2020): REVSTAT-Statistical Journal
Robust Estimation of Reduced Rank Models to Large Spatial Datasets
Creators: name: M. Jelsema, Casey
name: Paul, Rajib
name: W. McKean, Joseph
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: For large datasets, spatial covariances are often modeled using basis functions and covariance of a reduced dimensional latent spatial process. For skewed data, likelihood based approaches with Gaussian assumption may not lead to faithful inference. Any L2 norm based estimation is susceptible to long tails and outliers due to contamination. Our method is based on an empirical binned covariance matrix using the median absolute deviation and minimizes L1 norm between empirical covariance and the model covariance. The consistency of the proposed estimate is established theoretically. The improvement is demonstrated using simulated data and cloud data obtained from NASA’s Terra satellite.
description: REVSTAT-Statistical Journal, Vol. 18 No. 2 (2020): REVSTAT-Statistical Journal
Testing for Trends in Excesses Over a Threshold Using the Generalized Pareto Distribution
Creators: name: Rojo, Javier
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: The Generalized Pareto Distribution (GPD) is used for modeling exceedances over thresholds. The general form of the GPD depends on three parameters: the location parameter µ; the scale parameter (β > 0); and the shape parameter (−∞ < ξ < ∞). This work restricts attention to the case where µ = 0 and shows that, as ξ decreases while β is kept fixed, the family of GPD(ξ, β) distributions increases in the usual stochastic order. This property is used for testing the significance of trends in the size of the exceedances over high thresholds in a time series consisting of ozone measurements.
description: REVSTAT-Statistical Journal, Vol. 18 No. 2 (2020): REVSTAT-Statistical Journal
Arnold–Villasenor Conjectures for ˜ Characterizing Exponential Distribution Based on Sample of Size Three
Creators: name: P. Yanev, George
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: Arnold and Villase˜nor [4] obtain a series of characterizations of the exponential distribution based on random samples of size two. These results were already applied in constructing goodness-of-fit tests in [7]. Extending the techniques from [4], we prove some of Arnold and Villase˜nor’s conjectures for samples of size three. An example with simulated data is discussed.
description: REVSTAT-Statistical Journal, Vol. 18 No. 2 (2020): REVSTAT-Statistical Journal
Variance Estimation Using Randomized Response Technique
Creators: name: Gupta, Sat
name: Nouman Qureshi, Muhammad
name: Khalil, Sadia
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: Variance estimation is a well-studied topic in survey sampling but not much work has been done in this area in the context of Randomized Response Technique (RRT) models. We propose here some variance estimators for sensitive variables using auxiliary information. We examine the performance of the proposed estimators through a simulation study and through a numerical example.
description: REVSTAT-Statistical Journal, Vol. 18 No. 2 (2020): REVSTAT-Statistical Journal
Simultaneous Inference of Gene Isoform Expression for RNA Sequencing Data
Creators: name: Li, Bo
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: In this article, we describe simultaneous inferential methods in detecting differentially expressed gene isoforms based on the Poisson generalized linear models. We derive the joint asymptotic distribution of pivotal quantities. The sample size of RNA sequencing data is often small in practice. Using multiple comparison procedures based on large-sample approximation becomes problematic. The parametric bootstrap method based on pivotal quantities is outlined as a robust alternative. Moreover, we observe the validity of robustness of the bootstrap method when mild overdispersion presents in RNA-sequencing data. We demonstrate the validity of the proposed method in detecting differentially expressed isoforms through Monte Carlo simulation. It shows the proposed method controls the family-wise error rate for large-scale inference. Even though the proposed method can be extended to many experimental designs, we focus on factorial designs in this article.
description: REVSTAT-Statistical Journal, Vol. 18 No. 2 (2020): REVSTAT-Statistical Journal
Prediction Intervals for Time Series and their Applications to Portfolio Selection
Creators: name: Huang, Shih-Feng
name: Hsu, Hsiang-Ling
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: This study considers prediction intervals for time series and applies the results to portfolio selection. The dynamics of the high and low underlying returns are depicted by time series models, which lead to a prediction interval of future returns. We propose an innovative criterion for portfolio selection based on the prediction interval. A new concept of coherent risk measures for the interval of returns is introduced. An empirical study is conducted with the stocks of the Dow Jones Industrial Average Index. A self-financing trading strategy is established by daily reallocating the holding positions via the proposed portfolio selection criterion. The numerical results indicate that the proposed prediction interval has promising coverage, efficiency and accuracy for prediction. The proposed portfolio selection criterion constructed from the prediction intervals is capable of suggesting an optimal portfolio according to the economic conditions.
description: REVSTAT-Statistical Journal, Vol. 18 No. 1 (2020): REVSTAT-Statistical Journal
Depth-Based Signed-Rank Tests for Bivariate Central Symmetry
Creators: name: Dehghan, Sakineh
name: Reza Faridrohani, Mohammad
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: In this paper, distribution-free, affine invariant, signed-rank test statistics are proposed for the hypothesis that a bivariate distribution is centrally symmetric about an arbitrary specified point. The proposed tests are based on the concept of data depth. However, our tests are inherently orthogonal invariant, an affine invariant version of them is provided by using Tyler’s estimator of scatter. The limiting null distribution of proposed tests is derived and the performance of the proposed tests is evaluated through a Monte Carlo study. This study demonstrates that the tests always detect asymmetry and they are convenient to determine small departures from the null hypothesis with high power. Also it shows that the tests perform well comparing other procedures in the literature.
description: REVSTAT-Statistical Journal, Vol. 18 No. 1 (2020): REVSTAT-Statistical Journal
Transition Model for Analysis of Zero-Inflated Longitudinal Count Data Using Generalized Poisson Regression Model
Creators: name: Baghfalaki, Taban
name: Ganjali, Mojtaba
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: In most of the longitudinal studies, involving count responses, excess zeros are common in practice. Usually, the current response measurement in a longitudinal sequence is a function of previous outcomes. For example, in a study about acute renal allograft rejection, the number of acute rejection episodes for a patient in current time is a function of this outcome at previous follow-up times. In this paper, we consider a transition model for accounting the dependence of current outcome on the previous outcomes in the presence of excess zeros. We propose the use of the generalized Poisson distribution as a flexible distribution for considering overdispersion (or underdispersion). The maximum likelihood estimates of the parameters are obtained using the EM algorithm. Some simulation studies are performed for illustration of the proposed methods. Also, analysis of a real data set of a kidney allograft rejection study illustrates the application of the proposed model.
description: REVSTAT-Statistical Journal, Vol. 18 No. 1 (2020): REVSTAT-Statistical Journal
Characterization of the Maximum Probability Fixed Marginals R×C Contingency Tables
Creators: name: Requena, Francisco
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: In this paper operators i[j] and [j]k are defined, whose effects on an r×c contingency table X are to subtract 1 from xij and to add 1 to xkj , respectively, so that the composition i[j]k of the two operators changes the j-th column of the contingency table without altering its total. Also a loop is defined as a composition of such operators that leaves unchanged both row and column totals. This is used to characterize the r×c contingency tables of maximum probability over the fixed marginals reference set (under the hypothesis of row and column independence). Another characterization of such maximum probability tables is given using the concept of associated U tables, a U = {uij} table being defined as a table such that uij > 0, 1 ≤ i ≤ r and 1 ≤ j ≤ c, and for a given set of values rh, 1 ≤ h < r, uh+1,j = rhuhj for all j. Finally, a necessary and sufficient condition for the uniqueness of a maximum probability table in the fixed marginals reference set is provided.
description: REVSTAT-Statistical Journal, Vol. 18 No. 1 (2020): REVSTAT-Statistical Journal
Supplementary document for Advanced mechanism of multiphysics fields tip enhancement (MFTE) induced with varied laser power to fabricate patterntransformable sub-diffraction limit nanostructures - 5504818.pdf
Creators: name: Yin, HaiLong
name: Dong, Xiangyang
name: Wang, Xuewen
name: Cui, Jian
name: Wang, Wenjun
name: Mei, Xuesong
Publisher: name: Optica Publishing Group
Year: 2025
Subjects: Uncategorized

description: Fig.s1 to Fig.s3 were new supplementary figures.
Die Wirkung lehrerinitiierter Aufrufe auf Schülerinnen und Schüler aus Sicht der Lehrkräfte (Arbeitstitel)
Creators: name: Stöckel, Lea
Publisher: name: PsychArchives
Year: 2024
Subjects: subject: 150

description: Lernmotivation und kognitive Lernaktivität von Schüler:innen nehmen mit der aktiven Beteiligung am Unterricht zu (Lipowsky et al., 2007). Das Ziel der Lehrenden muss deshalb die Beteiligung möglichst vieler Schüler:innen sein. Um dies zu erreichen, rufen Lehrpersonen auch Schüler:innen im Unterricht auf, die sich nicht selber gemeldet haben (Sacher, 1995). Studien belegen allerdings, dass die Wirkung lehrerinitiierter Aufrufe auch negative Auswirkungen auf das Selbstkonzept von Schüler:innen haben können (Denn, 2021). Das Ziel dieser Studie ist es herauszufinden, wie häufig Lehrkräfte lehrerinitiierte Aufrufe nutzen und wie sie deren Wirkung im Unterricht auf das Selbstkonzept und die Motivation zur Mitarbeit der Schüler:innen einschätzen. Zudem wird untersucht, ob das Geschlecht und die Schulform der Lehrkraft diese Einschätzungen beeinflussen. Um die Forschungsfragen zu beantworten, nehmen an der Umfrage Lehrkräfte unterschiedlicher Schulformen aus Nordrhein-Westfalen teil. Bei dieser Umfrage beantworten die Teilnehmenden selbstständig 50 Items, die sich auf zehn Item-Gruppen verteilen. Als Antwortskala dient eine fünf-stufige Likert-Skala.
Numerical Solutions to the one dimensional Heat Equation
Creators: name: Ul Abideen, Zain
Publisher: name: Zenodo
Year: 2024

description: This study details the procedure for solving the one dimensional heat equation using the finite difference method. The initial conditions and the boundary conditions have to be provided. The final iterative formula for the solution to the partial differential equation was implemented in the Scilab language using nested $for$ loops. The results were visualized by looping over all the rows in the resulting matrix.
Leptoplectus vagans Lobl 1975
Creators: name: Byeon, Ui-Joung
name: Jang, Min-Sang
name: Park, Sun-Jae
name: Kim, A-Young
name: Park, Jong-Seok
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Leptoplectus
Leptoplectus vagans

description: LEPTOPlECTUS vaganS Löbl, 1975
 Leptoplectus vagans Löbl 1975: 114; Schülke and Smetana 2015: 382.
 Comments. A single male specimen is known only from northern part of the Korean Peninsula (Fig. 6). The description and aedeagus illustrations of this species were provided in Löbl (1975: 114). In this species the head is wider than long, broader than pronotum and has a U-shaped vertexal sulcus; pronotum broadest in anterior; each elytron with three basal foveae; abdomen longer than elytra; aedeagus with apical projection absent and median lobe not divided.
description: Published as part of Byeon, Ui-Joung, Jang, Min-Sang, Park, Sun-Jae, Kim, A-Young & Park, Jong-Seok, 2021, Review of Korean Species of the Genus Leptoplectus Casey (Coleoptera: Staphylinidae: Pselaphinae: Euplectitae) with Description of a New Species, pp. 689-694 in The Coleopterists Bulletin 75 (3) on page 693, DOI: 10.1649/0010-065X-75.3.689, http://zenodo.org/record/13251388
What causes post-correct slowing?
Creators: name: Van 'T Wout, Félice
Publisher: name: PsychArchives
Year: 2022
Subjects: subject: 150

description: One of the most robust findings in the cognitive psychology literature is that participants are typically slower following an error (Rabbitt, 1966). According to cognitive control theories (e.g., Botvinick et al., 2001), such “post error slowing” is thought to reflect a strategic adjustment to encourage more careful behaviour and avoid future errors. Strikingly, under certain circumstances (for example, when errors are more frequent than correct responses), the opposite pattern can also be observed, and reaction times are slower following a correct response (e.g., Van ‘t Wout & Jarrold, 2022). The cause of such “post correct slowing” remains poorly understood, though proposed explanations include variations in the response-stimulus interval (RSI; e.g., Jentz & Dudschig, 2009), the ratio of correct to incorrect responses (Notebaert et al., 2009), and time taken to update the task-set representation (Van ‘t Wout & Jarrold, 2022). This experiment will investigate some of these proposed explanations, in order to elucidate the cognitive mechanisms that underpin post-error processing.
Occurrence of Boundary Solutions in Two-Way Incomplete Tables
Creators: name: Ghosh, Sayan
name: Vellaisamy, Palaniappan
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: The analysis of incomplete contingency tables is an important problem, which is also of practical interest. In this paper, we consider boundary solutions under nonignorable nonresponse models in two-way incomplete tables with data on both variables missing. We establish a result similar to [9] on sufficient conditions for the occurrence of boundary solutions. We also provide a new result, which connects the forms of boundary solutions under various parameterizations of the missing data models. This result helps us to obtain the exact form of boundary solutions in the above tables, which improves a claim made in [2] and avoids computational burden. A counterexample is provided to show that the sufficient conditions for the occurrence of boundary solutions are not necessary, thereby disproving a conjecture of [7]. Finally, we establish new necessary conditions for the occurrence of boundary solutions under nonignorable nonresponse models in square two-way incomplete tables, and show that they are not sufficient. These conditions are simple and easy to check as they depend only on the observed cell counts. They are useful and important for model selection also. Some real life data sets are analyzed to illustrate the results.
description: REVSTAT-Statistical Journal, Vol. 18 No. 1 (2020): REVSTAT-Statistical Journal
Anxiety and attentional control: identifying the nature and extent of anxiety-related working memory difficulties in young people
Creators: name: Attwood, Meg
name: Jarrold, Christopher
Publisher: name: PsychArchives
Year: 2022
Subjects: subject: 150

description: This study builds on previous work to investigate the nature and extent of anxiety-related working memory difficulties in young people. Anxiety is understood to diminish top-down control of attention. As such, anxious individuals exhibit greater susceptibility to distraction and reduced flexibility in allocating attention to task-relevant stimuli. While working memory plays a key explanatory role in models of anxiety, mixed empirical findings highlight the need for a more nuanced account of the relationship between anxiety, attentional control and working memory. Anxious psychopathology typically emerges in adolescence. Clarifying the role working memory processes play in the onset and maintenance of anxiety symptoms has important implications for both theory and intervention. The aim of this study is to investigate the interplay between anxiety and attentional control in shaping young people’s working memory performance and in particular, their susceptibility to distraction. A key objective is to identify the nature of any anxiety-related attentional control difficulties in this age group and to relate these to particular working memory processes (e.g., encoding, maintenance) and outcomes (e.g., speed of processing, recall accuracy). 200 participants (aged 18 - 24 years) will be recruited via Prolific and through the University of Bristol's Experimental Hours scheme. The main experimental task is an integrated complex span task. Under conditions of varying attentional demand, lists of to-be-remembered items (4, 6, 8 words) must be categorised and stored for later recall. Two further tasks split the integrated task into its component parts – simple span and processing - and these are performed under the same attentional manipulation. Participants will also complete self-report measures of attentional control difficulties and trait- and state-anxiety.
Nonparametric Regression Based on Discretely Sampled Curves
Creators: name: Forzani, Liliana
name: Fraiman, Ricardo
name: Llop, Pamela
Publisher: name: REVSTAT-Statistical Journal
Year: 2020

description: In the context of nonparametric regression, we study conditions under which the consistency (and rates of convergence) of estimators built from discretely sampled curves can be derived from the consistency of estimators based on the unobserved whole trajectories. As a consequence, we derive asymptotic results for most of the regularization techniques used in functional data analysis, including smoothing and basis representation.
description: REVSTAT-Statistical Journal, Vol. 18 No. 1 (2020): REVSTAT-Statistical Journal
Forecasting Daily Exchange Rates
Creators: name: Mahmoudvand, Rahim
name: Canas Rodrigues, Paulo
name: Yarmohammadi, Masoud
Publisher: name: REVSTAT-Statistical Journal
Year: 2019

description: In this paper, daily exchange rates in four of the BRICS emerging economies: Brazil, India, China and South Africa, over the period 2001 to 2015 are considered. In order to predict the future of exchange rate in these countries, it is possible to use both univariate and multivariate time series techniques. Among different time series analysis methods, we choose singular spectrum analysis (SSA), as it is a relatively powerful non-parametric technique and requires the fewest assumptions to be hold in practice. Both multivariate and univariate versions of SSA are considered to predict the daily currency exchange rates. The results show the superiority of MSSA, when compared with univariate SSA, in terms of mean squared error.
description: REVSTAT-Statistical Journal, Vol. 17 No. 4 (2019): REVSTAT-Statistical Journal
Predictive Estimation of Population Mean in Ranked Set Sampling
Creators: name: Ahmed, Shakeel
name: Shabbir, Javid
name: Gupta, Sat
Publisher: name: REVSTAT-Statistical Journal
Year: 2019

description: The article presents predictive estimation of population mean of the study variable in Ranked Set Sampling (RSS). It is shown that the predictive estimators in RSS using mean per unit estimator, ratio estimator and regression estimator as predictor for non-sampled values are equivalent to the corresponding classical estimators in RSS. On the other hand, when product estimator is used as predictor, the resulting estimator differs from the classical product estimator under RSS. Expressions for the Bias and the Mean Squared Error (MSE) of the proposed estimators are obtained up to first order of approximation. A simulation study is conducted to observe the performance of estimators under predictive approach.
description: REVSTAT-Statistical Journal, Vol. 17 No. 4 (2019): REVSTAT-Statistical Journal
Repeated Measures Analysis for Functional Data Using Box-Type Approximation
Creators: name: Smaga, Lukasz
Publisher: name: REVSTAT-Statistical Journal
Year: 2019

description: The repeated measures analysis for functional data is investigated. In the literature, the test statistic for the two-sample problem when data are from the same subject is considered. Unfortunately, the known permutation and bootstrap approximations for distribution of it may be time-consuming. To avoid this drawback, a Box-type approximation for asymptotic null distribution of that test statistic is proposed. This approximation results in a new testing procedure, which is more efficient from a computational point of view than the known ones. Root-n consistency of the new method is also proved. Via intensive simulation studies, it is found that in terms of size control and power, the new test is comparable with the known tests. An illustrative example of the use of tests in practice is also given.
description: REVSTAT-Statistical Journal, Vol. 17 No. 4 (2019): REVSTAT-Statistical Journal
Generalized Estimators of Stationary Random-Coefficients Panel Data Models
Creators: name: Reda Abonazel, Mohamed
Publisher: name: REVSTAT-Statistical Journal
Year: 2019

description: This article provides generalized estimators for the random-coefficients panel data (RCPD) model where the errors are cross-sectional heteroskedastic and contemporaneously correlated as well as with the first-order autocorrelation of the time series errors. Of course, under the new assumptions of the error, the conventional estimators are not suitable for RCPD model. Therefore, the suitable estimator for this model and other alternative estimators have been provided and examined in this article. Furthermore, the efficiency comparisons for these estimators have been carried out in small samples and also we examine the asymptotic distributions of them. The Monte Carlo simulation study indicates that the new estimators are more efficient than the conventional estimators, especially in small samples.
description: REVSTAT-Statistical Journal, Vol. 17 No. 4 (2019): REVSTAT-Statistical Journal