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Factors determining waste generation in Spanish towns and cities

ENVIRONMENTAL MONITORING AND ASSESSMENT 2015年第1期187卷 1页

作者： Prades, Miriam Gallardo, Antonio Victoria Ibanez, Maria Univ Jaume 1 Dept Mech Engn & Construct Castellon de La Plana 12071 Spain Univ Jaume 1 Inst Math & Applicat Dept Math Castellon de La Plana 12071 Spain

This paper analyzes the generation and composition of municipal solid waste in Spanish towns and cities with more than 5000 inhabitants, which altogether account for 87 % of the Spanish population. To do so, the total composition and generation of municipal solid waste fractions were obtained from 135 towns and cities. Homogeneity tests revealed heterogeneity in the proportions of municipal solid waste fractions from one city to another. Statistical analyses identified significant differences in the generation of glass in cities of different sizes and in the generation of all fractions depending on the hydrographic area. Finally, linear regression models and residuals analysis were applied to analyze the effect of different demographic, geographic, and socioeconomic variables on the generation of waste fractions. The conclusions show that more densely populated towns, a hydrographic area, and cities with over 50,000 inhabitants have higher waste generation rates, while certain socioeconomic variables (people/car) decrease that generation. Other socioeconomic variables (foreigners and unemployment) show a positive and null influence on that waste generation, respectively.

关键词： Waste generation Waste composition Homogeneity linear regression models

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Frequency estimation of a sinusoidal signal with time-varying amplitude*

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IFAC-PapersOnLine 2017年第1期50卷 12880-12885页

作者： Vedyakov, Alexey A. Vediakova, Anastasiia O. Bobtsov, Alexey A. Pyrkin, Anton A. Aranovskiy, Stanislav V. Department of Control Systems and Informatics ITMO University Kronverkskiy pr. 49 St. Petersburg197101 Russia Department of Computer Applications and Systems St.Petersburg State University 7/9 Universitetskaya nab. St. Petersburg199034 Russia Laboratory “Control of Complex Systems” Institute of Problems of Mechanical Engineering V.O. Bolshoj pr. 61 St. Petersburg199178 Russia CentraleSupélec IETR Avenue de la Boulaie Cesson-Sévigné35576 France

This paper is devoted to frequency estimation of a sinusoidal signal with a time-varying amplitude. The amplitude can take zero values, but should be known and bounded. The first order linear regression model is obtained. The estimation algorithm has been constructed basing on standard gradient approach. It is shown that the frequency estimation error converges to zero exponentially fast. The described algorithm does not require measuring or calculating derivatives of the input signal. The efficiency of the proposed approach is demonstrated through a set of numerical simulations. © 2017

关键词： Frequency estimation Continuous time systems linear regression Continuous time estimations Estimation algorithm Frequency estimation errors Gradient approach Gray box models linear regression models Sinusoidal signals Time domain identification

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Generalized minimum distance estimators of a linear model with correlated errors

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STATISTICAL PAPERS 2001年第3期42卷 353-373页

作者： Fernández, JMV Manteiga, WG Univ A Coruna Fac Informat Coruna 15071 Spain Univ Santiago Fac Math Santiago 15706 Spain

In this paper we study a special class of minimum distance estimators, based on nonparametric pilot estimators of the regression function, for a parameter theta is an element of Theta subset of R-p of a linear regression model of the type Y = X theta + epsilon, where X is the design matrix, Y the vector of the response variable and epsilon the random error vector that follows an AR(1) correlation structure. These estimators are asymptotically analyzed, by proving their strong consistency, asymptotic normality and asymptotic efficiency. In a simulation study, a better behaviour of the Mean Squared Error of the proposed estimator with respect to that of the generalized least squares estimator is observed.

关键词： minimum distance estimators linear regression models nonparametric estimation AR(1) correlation structure

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Predicting wheat head blight incidence using models based on meteorological factors in Pergamino, Argentina

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EUROPEAN JOURNAL OF PLANT PATHOLOGY 1996年第3期102卷 211-218页

作者： Moschini, RC Fortugno, C INTA CASTELAR CICAINST FITOPATOL & FISIOL VEGETALBUENOS AIRESDFARGENTINA

A computer program using the language and statistical procedures available from SAS (Statistical Analysis System) was written in order to identify the most highly correlated meteorological factors with the incidence of wheat head blight (caused by Fusarium graminearum Schwabe) at Pergamino, in the humid pampeana region. Applying linear regression techniques, different models from simple up to a maximum of three independent variables were fitted to the data (1978-1990). The meteorological variables were processed in a time segment beginning eight days prior to the heading date (50% of emerged ears) and finishing when 530 degree days were accumulated (26-32 days). The number of two day periods with rainfall and relative humidity >81% in the first day and relative humidity greater than or equal to 78% in the second (NPPRH) was the variable that showed the strongest association with disease incidence (FI) (R(2) = 0.81). After examining the models in several ways (R(2), Adjusted R(2), PRESS statistic), two equations were selected: FI% = 20.37 + 8.63 NPPRH - 0.49 DDXNT (R(2) = 0.86) and FI% = 16.39 + 5.43 NPPRH - 0.45 DDXNT + 2.95 DPRH (R(2) = 0.886), in which DDXNT represents the daily accumulation of the residuals resulting from subtracting 9 to the minimum temperature values (<9 degrees C) and the exceeding amounts of maximum temperatures from 26 degrees C and DPRH is the number of days with precipitation and relative humidity greater than 83%. Successful local predictions of incidence of scab for the years 1991-1993 (reserved for validation purposes) were achieved using both equations.

关键词： disease incidence Fusarium graminearum head blight or scab linear regression models meteorological variables

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Tutorial on Biostatistics: Longitudinal Analysis of Correlated Continuous Eye Data

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OPHTHALMIC EPIDEMIOLOGY 2021年第1期28卷 3-20页

作者： Ying, Gui-Shuang Maguire, Maureen G. Glynn, Robert J. Rosner, Bernard Univ Penn Dept Ophthalmol Perelman Sch Med Ctr Prevent Ophthalmol & Biostat Philadelphia PA 19104 USA Brigham & Womens Hosp Dept Med Div Prevent Med 75 Francis St Boston MA 02115 USA Brigham & Womens Hosp Dept Med Channing Lab Boston MA USA

Purpose: To describe and demonstrate methods for analyzing longitudinal correlated eye data with a continuous outcome measure. Methods: We described fixed effects, mixed effects and generalized estimating equations (GEE) models, applied them to data from the Complications of Age-Related Macular Degeneration Prevention Trial (CAPT) and the Age-Related Eye Disease Study (AREDS). In CAPT (N = 1052), we assessed the effect of eye-specific laser treatment on change in visual acuity (VA). In the AREDS study, we evaluated effects of systemic supplement treatment among 1463 participants with AMD category 3. Results: In CAPT, the inter-eye correlations (0.33 to 0.53) and longitudinal correlations (0.31 to 0.88) varied. There was a small treatment effect on VA change (approximately one letter) at 24 months for all three models (p= .009 to 0.02). Model fit was better with the mixed effects model than the fixed effects model (p< .001). In AREDS, there was no significant treatment effect in all models (p> .55). Current smokers had a significantly greater VA decline than non-current smokers in the fixed effects model (p= .04) and the mixed effects model with random intercept (p= .0003), but marginally significant in the mixed effects model with random intercept and slope (p= .08), and GEE models (p= .054 to 0.07). The model fit was better with the fixed effects model than the mixed effects model (p< .0001). Conclusion: Longitudinal models using the eye as the unit of analysis can be implemented using available statistical software to account for both inter-eye and longitudinal correlations. Goodness-of-fit statistics may guide the selection of the most appropriate model.

关键词： linear regression models correlated data inter-eye correlation longitudinal correlation fixed effects model mixed effects model generalized estimating equations

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M-test in linear models with negatively superadditive dependent errors

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JOURNAL OF INEQUALITIES AND APPLICATIONS 2017年第1期2017卷 235页

作者： Yu, Yuncai Hu, Hongchang Liu, Ling Huang, Shouyou Nanjing Univ Aeronaut & Astronaut Inst Nano Sci State Key Lab Mech & Control Mech Struct Nanjing 210016 Jiangsu Peoples R China Nanjing Univ Aeronaut & Astronaut Dept Math Nanjing 210016 Jiangsu Peoples R China Hubei Normal Univ Dept Math & Stat Huangshi 435002 Peoples R China Donghua Univ Dept Informat Sci & Technol Shanghai 201600 Peoples R China

This paper is concerned with the testing hypotheses of regression parameters in linear models in which errors are negatively superadditive dependent (NSD). A robust M-test base on M-criterion is proposed. The asymptotic distribution of the test statistic is obtained and the consistent estimates of the redundancy parameters involved in the asymptotic distribution are established. Finally, some Monte Carlo simulations are given to substantiate the stability of the parameter estimates and the power of the test, for various choices of M-methods, explanatory variables and different sample sizes.

关键词： NSD random sequences linear regression models M-test asymptotic property Monte Carlo simulations

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Optimal designs which are efficient for lack of fit tests

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ANNALS OF STATISTICS 2006年第4期34卷 2015-2025页

作者： Bischoff, Wolfgang Miller, Frank Catholic Univ Eichstatt Ingolstadt D-85071 Eichstatt Germany AstraZeneca Clin Informat Sci S-15185 Sodertalje Sweden

linear regression models are among the models most used in practice, although the practitioners are often not sure whether their assumed linear regression model is at least approximately true. In such situations, only designs for which the linear model can be checked are accepted in practice. For important linear regression models such as polynomial regression, optimal designs do not have this property. To get practically attractive designs, we suggest the following strategy. One part of the design points is used to allow one to carry out a lack of fit test with good power for practically interesting alternatives. The rest of the design points are determined in such a way that the whole design is optimal for inference on the unknown parameter in case the lack of fit test does not reject the linear regression model. To solve this problem, we introduce efficient lack of fit designs. Then we explicitly determine the e(k)-optimal design in the class of efficient lack of fit designs for polynomial regression of degree k-1.

关键词： linear regression models testing lack of fit efficient maximin power polynomial regression of degree k-1 optimal designs to estimate the highest coefficient

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Frequency estimation of a sinusoidal signal with time-varying amplitude and phase

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IFAC-PapersOnLine 2018年第32期51卷 663-668页

作者： Vedyakov, Alexey A. Vediakova, Anastasiia O. Bobtsov, Alexey A. Pyrkin, Anton A. Kakanov, Mikhail A. ITMO University Kronverkskiy pr. 49 St. Petersburg197101 Russia Department of Computer Applications and Systems St.Petersburg State University 7/9 Universitetskaya nab. St. Petersburg199034 Russia Laboratory “Control of Complex Systems” Institute of Problems of Mechanical Engineering V.O. Bolshoj pr. 61 St. Petersburg199178 Russia

This paper is devoted to frequency estimation of a non-stationary sinusoidal signal. The amplitude is supposed to be a known function within a constant factor, the phase should be known. Example of such problem statement is sensorless angular velocity estimation for permanent magnet synchronous motors. On the first step by reparametrization, a third order linear regression model is obtained. On the next step, an estimation algorithm is constructed based on a standard gradient approach. The frequency estimate can be computed from one of the model parameters using inverse trigonometric functions. To improve estimates quality for noisy measurements we propose a new identification method, which can be tuned to attenuate the noise influence. It is shown that the frequency estimation error converges to zero exponentially fast. The described algorithm does not require measuring or calculating derivatives of the input signal. The efficiency of the proposed approach is demonstrated through the set of numerical simulations. © 2018

关键词： Frequency estimation Continuous time systems Inverse problems Permanent magnets regression analysis Angular velocity estimation Continuous time estimations Frequency estimation errors Globally convergent Identification method linear regression models Permanent Magnet Synchronous Motor Trigonometric functions

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Does sequential augmenting of simple linear heteroscedastic regression reduce variances of ordinary least-squares estimators?

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STATISTICS 2014年第5期48卷 1106-1121页

作者： Kozek, Andrzej S. Jersky, Brian Macquarie Univ Dept Stat Sydney NSW 2109 Australia Calif State Polytech Univ Pomona Coll Sci Pomona CA 91768 USA

If uncorrelated random variables have a common expected value and decreasing variances, then the variance of a sample mean is decreasing with the number of observations. Unfortunately, this natural and desirable variance reduction property (VRP) by augmenting data is not automatically inherited by ordinary least-squares (OLS) estimators of parameters. We derive a new decomposition for updating the covariance matrices of the OLS which implies conditions for the OLS to have the VRP. In particular, in the case of a straight-line regression, we show that the OLS estimators of intercept and slope have the VRP if the values of the explanatory variable are increasing. This also holds true for alternating two-point experimental designs.

关键词： augmented data design of experiment linear regression models ordinary least squares variance reduction

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Tutorial on Biostatistics: linear regression Analysis of Continuous Correlated Eye Data

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OPHTHALMIC EPIDEMIOLOGY 2017年第2期24卷 130-140页

作者： Ying, Gui-shuang Maguire, Maureen G. Glynn, Robert Rosner, Bernard Univ Penn Ctr Prevent Ophthalmol & Biostat Perelman Sch Med Dept Ophthalmol Philadelphia PA 19104 USA Brigham & Womens Hosp Dept Med Div Prevent Med Boston MA 02115 USA Brigham & Womens Hosp Dept Med Channing Lab Boston MA 02115 USA

Purpose: To describe and demonstrate appropriate linear regression methods for analyzing correlated continuous eye data. Methods: We describe several approaches to regression analysis involving both eyes, including mixed effects and marginal models under various covariance structures to account for inter-eye correlation. We demonstrate, with SAS statistical software, applications in a study comparing baseline refractive error between one eye with choroidal neovascularization (CNV) and the unaffected fellow eye, and in a study determining factors associated with visual field in the elderly. Results: When refractive error from both eyes were analyzed with standard linear regression without accounting for inter-eye correlation (adjusting for demographic and ocular covariates), the difference between eyes with CNV and fellow eyes was 0.15 diopters (D;95% confidence interval, CI -0.03 to 0.32D, p = 0.10). Using a mixed effects model or a marginal model, the estimated difference was the same but with narrower 95% CI (0.01 to 0.28D, p = 0.03). Standard regression for visual field data from both eyes provided biased estimates of standard error (generally underestimated) and smaller p-values, while analysis of the worse eye provided larger p-values than mixed effects models and marginal models. Conclusion: In research involving both eyes, ignoring inter-eye correlation can lead to invalid inferences. Analysis using only right or left eyes is valid, but decreases power. Worse-eye analysis can provide less power and biased estimates of effect. Mixed effects or marginal models using the eye as the unit of analysis should be used to appropriately account for inter-eye correlation and maximize power and precision.

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