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Engineering statistical models for carbonation depth

EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING 2023年第1期27卷 215-238页

作者： Kouassi, Franck Antelme Dauxois, Jean-Yves Duprat, Frederic De Larrard, Thomas Deby, Fabrice Inst Math Toulouse 135 Ave Rangueil F-31062 Toulouse France Univ Toulouse UMR5219 INSA CNRS 135 Ave Rangueil F-31062 Toulouse France Univ Toulouse Lab Mat & Durabilite Construct INSA UPS Toulouse France

Based on generalized linear models and gamma degradation processes, two models predicting the natural carbonation of reinforced concrete (R.C) structures are proposed. They include the main factors influencing the carbonation process (material, environmental and curing factors) and their effects are evaluated from a large sample of natural carbonation depths measured experimentally worldwide. Then, predicted carbonation values are obtained using both the proposed models and the fib model for sheltered R.C structures exposed in the field. It is revealed that the proposed models have a rather high level of accuracy compared to the fib model and may be proposed as valuable alternatives.

关键词： Reinforced concretes natural carbonation steel corrosion generalized linear models Gamma degradation process

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Bayesian models for spatial count data with informative finite populations with application to the American community survey

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JOURNAL OF APPLIED STATISTICS 2023年第13期50卷 2701-2716页

作者： Qu, Kai Bradley, Jonathan R. Florida State Univ Dept Stat Tallahassee FL 32306 USA

The American Community Survey (ACS) is an ongoing program conducted by the US Census Bureau that publishes estimates of important demographic statistics over pre-specified administrative areas. ACS provides spatially referenced count-valued outcomes that are paired with finite populations. For example, the number of people below the poverty line and the total population for each county are estimated by ACS. One common assumption is that the spatially referenced count-valued outcome given the finite population is binomial distributed. This conditionally specified (CS) model does not define the joint relationship between the count-valued outcome and the finite population. Thus, we consider a joint model for the count-valued outcome and the finite population. When cross-dependence in our joint model can be leveraged to 'improve spatial prediction' we say that the finite population is 'informative.' We model the count given the finite population as binomial and the finite population as negative binomial and use multivariate logit-beta prior distributions. This leads to closed-form expressions of the full-conditional distributions for an efficient Gibbs sampler. We illustrate our model through simulations and our motivating application of ACS poverty estimates. These empirical analyses show the benefits of using our proposed model over the more traditional CS binomial model.

关键词： Bayesian statistics spatial statistics official statistics generalized linear models conjugate

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Prokaryotic Plankton and Viruses in the Waters of the Fram Strait in the Winter Period

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RUSSIAN JOURNAL OF MARINE BIOLOGY 2023年第6期49卷 461-468页

作者： Venger, M. P. Dvoretsky, V. G. Vashchenko, A. V. Ishkulova, T. G. Maksimovskaya, T. M. Vodopyanova, V. V. Russian Acad Sci Murmansk Marine Biol Inst Murmansk 183010 Russia

New data have been obtained on the distribution of prokaryotic plankton and pelagic viruses in the Fram Strait (the Greenland Sea) during the polar night (late November). Three main types of water masses were present in the study area: surface polar, Atlantic, and transformed Atlantic. The content of mineral biogenic elements increased with depth. The concentration of chlorophyll a had low values (0.07-0.13 mg/m(3)). The abundance and biomass of prokaryotes varied from 286000 to 675000 cells/mL and from 2.7 to 11.7 mg C/m(3), respectively. The composition of prokaryotic plankton was dominated by single small cells (more than 97% of the abundance and more than 68% of the biomass). The average cell volume was 0.034-0.096 mu m(3). The number of viruses varied from 724000 to 3920000 particles/mL, and the biomass varied from 0.040 to 0.216 mu g C/m(3). Against the background of local maxima in the abundance of prokaryotic plankton in the 0-25 m layer, the highest concentrations of viruses were noted in the surface layer. In the latitudinal distribution (from south to north), an increase in the number of viruses and prokaryotes was revealed. A close relationship between their abundance and biomass with hydrological parameters and phosphate content was established;the role of certain water masses in the vertical distribution of microbes was insignificant. The relatively high abundance of viruses and prokaryotes indicated their significant activity during the polar night.

关键词： heterotrophic prokaryotic plankton virioplankton water masses environmental impact generalized linear models Arctic

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SYMARFIMA: A dynamical model for conditionally symmetric time series with long range dependence mean structure

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JOURNAL OF STATISTICAL PLANNING AND INFERENCE 2023年 225卷 71-88页

作者： Benaduce, Helen da Silva Costa Pumi, Guilherme Univ Fed Rio Grande Do Sul Grad Program Stat 9500 Bento Goncalves Ave BR-91509900 Porto Alegre RS Brazil

In this work we introduce a dynamical model for conditionally symmetric time series accommodating a long range dependent structure for the conditional mean. More specifically, the proposed model specify the underlying distribution of the time series, conditionally to its past, to be symmetric. The conditional mean is specified to accom-modate a long range dependent structure, following an ARFIMA-like design, as well as a (possibly time dependent) set of regressors. We provide conditions for the existence and stationarity of the proposed model as well as closed formulas for its unconditional mean, variance and covariance structure. Parameter estimation is carried out via partial likelihood. The score vector and Hessian are obtained in closed forms. A finite sample study of the proposed partial likelihood estimation is carried out. To show the usefulness of the proposed model, we present an application to a real data set related to wind speed in certain locations in Brazil. (c) 2022 Elsevier B.V. All rights reserved.

关键词： Dynamic models Long range dependent processes Symmetric distribution Time series analysis generalized linear models

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Coherent extrapolation of mortality rates at old ages applied to long term care

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EUROPEAN ACTUARIAL JOURNAL 2024年第1期14卷 145-174页

作者： Le Bastard, Leonie SCOR 5 Ave Kleber F-75795 Paris 16 France Univ Claude Bernard Lyon 1 SAF Lab Univ Lyon Inst Sci Financiere & Assurances Lab Sci Actuarielle & Financiere 50 Ave Tony Garnier F-69007 Lyon France

In an insurance context, Long-Term Care (LTC) products cover the risk of permanent loss of autonomy, which is defined by the impossibility or difficulty of performing alone all or part of the activities of daily living (ADL). From an actuarial point of view, knowledge of risk depends on knowledge of the underlying biometric laws, including the mortality of autonomous insureds and the mortality of disabled insureds. Due to the relatively short history of LTC products and the age limit imposed at underwriting, insurers lack information at advanced ages. This represents a challenge for actuaries, making it difficult to estimate those biometric laws. In this paper, we propose to complete the missing information at advanced ages on the mortality of autonomous and disabled insured populations using information on the global mortality of the portfolio. In fact, the three previous mortality laws are linked since the portfolio is composed only of autonomous and disabled policyholders. We model the two mortality laws (deaths in autonomy and deaths in LTC) in a Poisson generalized linear Model framework, additionally using the P-Splines smoothing method. A constraint is then included to link the mortality laws of the two groups and the global mortality of the portfolio. This new method allows for estimating and extrapolating both mortality laws simultaneously in a consistent manner.

关键词： Long-term care insurance Actuarial modelling generalized linear models P-Splines Extrapolation Penalization

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Robust regression against heavy heterogeneous contamination

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METRIKA 2023年第4期86卷 421-442页

作者： Kawashima, Takayuki Fujisawa, Hironori RIKEN Tokyo Insitute Technol Tokyo Japan RIKEN Inst Stat Math Tokyo Japan

The gamma-divergence is well-known for having strong robustness against heavy contamination. By virtue of this property, many applications via the gamma-divergence have been proposed. There are two types of gamma-divergence for the regression problem, in which the base measures are handled differently. In this study, these two gamma-divergences are compared, and a large difference is found between them under heterogeneous contamination, where the outlier ratio depends on the explanatory variable. One gamma-divergence has the strong robustness even under heterogeneous contamination. The other does not have in general;however, it has under homogeneous contamination, where the outlier ratio does not depend on the explanatory variable, or when the parametricmodel of the response variable belongs to a location-scale family in which the scale does not depend on the explanatory variables. Hung et al. (Biometrics 74(1):145-154, 2018) discussed the strong robustness in a logistic regression model with an additional assumption that the tuning parameter gamma is sufficiently large. The results obtained in this study hold for any parametric model without such an additional assumption.

关键词： Robust regression Divergence Heterogeneous contamination generalized linear models

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Design and Sample Size Determination for Experiments on Nonresponse Followup using a Sequential Regression Model

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JOURNAL OF OFFICIAL STATISTICS 2023年第2期39卷 173-202页

作者： Raim, Andrew M. Mathew, Thomas Sellers, Kimberly F. Ellis, Renee Meyers, Mikelyn US Census Bur Washington DC 20233 USA

Statistical agencies depend on responses to inquiries made to the public, and occasionally conduct experiments to improve contact procedures. Agencies may wish to assess whether there is significant change in response rates due to an operational refinement. This work considers the assessment of response rates when up to L attempts are made to contact each subject, and subjects receive one of J possible variations of the operation under experimentation. In particular, the continuation-ratio logit (CRL) model facilitates inference on the probability of success at each step of the sequence, given that failures occurred at previous attempts. The CRL model is investigated as a basis for sample size determination- one of the major decisions faced by an experimenter-to attain a desired power under a Wald test of a general linear hypothesis. An experiment that was conducted for nonresponse followup in the United States 2020 decennial census provides a motivating illustration.

关键词： Continuation-ratio logit design of experiments general linear hypothesis generalized linear models embedded experiments

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Type-II progressive censoring with GLM-based random removal mechanism dependent on the experimental conditions

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JOURNAL OF APPLIED STATISTICS 2023年第16期50卷 3199-3228页

作者： Darzi, Fatemeh Hassantabar Mahabadi, Samaneh Eftekhari Haghighi, Firoozeh Univ Tehran Coll Sci Sch Math Stat & Comp Sci Tehran 141556455 Iran

This article presents a novel stochastic removal mechanism under Type-II progressive random censoring in which removal probabilities are allowed to be dependent on the lifetime conditions through generalized linear models (GLM). These conditions potentially include failure distances (the time required to observe the next failure) or other covariate information available in the experiment. The proposed GLM-based random removal mechanism includes a set of tuning parameters that are determined by the researcher according to the possible failure distance category. These parameters allow flexible determination of the removal probabilities leading to necessary experimental cost and time reductions. To establish the proposed mechanism, the Proportional Hazard Rate (PHR) family of distributions is considered. Also, the maximum likelihood estimators of parameters and their asymptotic variances are derived for the Weibull distributed lifetime data. A simple simulation algorithm for generating Type-II progressive censoring samples with GLM-based dependent removal probabilities is also presented. The expected experiment time required to complete the life test under this censoring scheme is also investigated using the Monte Carlo integration method. Several simulation studies are conducted to evaluate and compare the performance of the proposed mechanism. A sensitivity analysis is also considered to study the effect of misspecification of removal mechanism coefficients. Finally, two real data sets are analyzed for illustrative purposes.

关键词： Type-II progressive censoring stochastic dependent random removal generalized linear models proportional hazard rate family expected experiment time

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A multi-state model for sick leave and its impact on partial early retirement incentives: the case of the Netherlands

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SCANDINAVIAN ACTUARIAL JOURNAL 2023年第3期2023卷 244-268页

作者： van Otterloo, Sophie de Mol Alonso-Garcia, Jennifer Minist Van Financien The Hague Netherlands Univ Libre Bruxelles Dept Math Brussels Belgium UNSW Sydney ARC Ctr Excellence Populat Ageing Res CEPAR Kensington NSW Australia Netspar Tilburg Netherlands

We investigate the effect of part-time and full-time work on health using a Markov framework and generalized linear models to smooth the resulting crude rates. The Chapman-Kolmogorov equations are used for a general solution. We apply this model to assess a partial early retirement incentive in the Netherlands, known as 'the generation pact'. The smoothed rates imply that working part time does not necessarily mean a better health for the elderly. In fact, men are healthier when working full time, while women fall sick more often when working full time but recover more often as well. However, when comparing the future rates of a person currently aged 50 working full time and using the generation pact, both the recovery and the morbidity rates drop when starting the generation pact. A stylized assessment of the costs associated yields that costs drop by half when using the generation pact.

关键词： Gradual retirement sick leave multiple state model generalized linear models

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Does the size of a protected area matter? An assessment of leopard population and habitat usage in a protected area of Shiwalik foothills, Himalaya

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MAMMAL RESEARCH 2023年第4期68卷 459-469页

作者： Sehgal, Janam Jai Panda, Debashish Kumar, Deepak Kalsi, Rajiv Allen, Maximilian. L. L. Singh, Randeep Amity Univ Amity Inst Forestry & Wildlife Noida 201301 Uttar Pradesh India Mukand Lal Natl Coll Dept Zool Yamunanagar 135001 Haryana India Univ Illinois Illinois Nat Hist Survey 1816S Oak St Champaign IL 61820 USA

Small protected areas, while often considered less important than large protected areas, are also important for the conservation of wide-ranging and low-density large carnivore populations. But these protected areas must have a sufficient prey base, controlled wildlife crime, and interconnectivity with other protected areas in order to be effective. In the foothills of Shiwalik, Himalaya, the 46.8 km(2) Kalesar National Park (KNP) is a dry deciduous forest. We used data collected with camera traps to estimate leopard density using spatial explicit capture-recapture (SECR) model and to model the effects of ecological and anthropogenic variables on habitat use of leopard using generalized linear models. The estimated leopard density was 19.31 & PLUSMN;5.10 (S.E.) individuals/100 km(2), which is high as compared to many other areas on the Indian subcontinent. Leopard habitat use was positively associated with sambar and wild boar availability, tree number, human disturbance, and distance to road and was negatively associated with chital availability and distance to water. KNP likely has a high density of leopards due to high prey availability and the absence of a dominant competitor (lions or tigers), despite high human disturbance and livestock presence throughout the park. This study will serve as an important baseline for insights into the population dynamics of leopards and creating conservation and management strategies in small protected areas such as KNP. Our results suggest the considerable conservation potential of small protected areas, and we propose that such areas might help to achieve conservation goals.

关键词： Population density Panthera pardus Camera traps Space use Kalesar National Park Spatial explicit capture-recapture generalized linear models

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