Search results for "GLM"
showing 10 items of 36 documents
Fitting generalized linear models with unspecified link function: A P-spline approach
2008
Generalized linear models (GLMs) outline a wide class of regression models where the effect of the explanatory variables on the mean of the response variable is modelled throughout the link function. The choice of the link function is typically overlooked in applications and the canonical link is commonly used. The estimation of GLMs with unspecified link function is discussed, where the linearity assumption between the link and the linear predictor is relaxed and the unspecified relationship is modelled flexibly by means of P-splines. An estimating algorithm is presented, alternating estimation of two working GLMs up to convergence. The method is applied to the analysis of quit behavior of…
Explaining German outward FDI in the EU: a reassessment using Bayesian model averaging and GLM estimators
2021
The last decades have seen an increasing interest in FDI and the process of production fragmentation. This has been particularly important for Germany as the core of the European Union (EU) production hub. This paper attempts to provide a deeper under standing of the drivers of German outward FDI in the EU for the period 1996–2012 by tackling the two main challenges faced in the modelization of FDI, namely the variable selection problem and the choice of the estimation method. For that purpose, we first extend previous BMA analysis developed by Camarero et al. (Econ Model 83:326–345, 2019) by including country-pair-fixed effects to select the appropriate set of variables. Second, we compare…
A gradient-based deletion diagnostic measure for generalized linear mixed models
2016
ABSTRACTA gradient-statistic-based diagnostic measure is developed in the context of the generalized linear mixed models. Its performance is assessed by some real examples and simulation studies, in terms of ability in detecting influential data structures and of concordance with the most used influence measures.
The Performance of the Gradient-Like Influence Measure in Generalized Linear Mixed Models
2015
A gradient-like statistic, recently introduced as an influence measure, has been proven to work well in large sample, thanks to its asymptotic properties. In this work, through small-scale simulation schemes, the performance of such a diagnostic measure is further investigated in terms of concordance with the main influence measures used for outlier identification. The simulation studies are performed by using generalized linear mixed models (GLMMs).
Saistība starp briofītu funkcionālajām grupām, substrātu īpašībām un mežau augu sabiedrībām Moricsalas dabas rezervātā
2013
Anotācija Darba mērķis ir noskaidrot substrāta parametru ietekmi uz briofītu sugu bagātību, sugu sastopamību un sugu sadalījumu pa funkcionālajām grupām (dzīves formu un dzīves stratēģiju) dažādās meža augu sabiedrībās, kā arī izpētīt sūnu sugu sastāva mainību Moricsalā pēdējo 100 gadu laikā. Par pētāmo teritoriju izvēlēts Moricsalas dabas rezervātā, kas ir senākā aizsargājamā dabas teritorija Latvijā un ilgstoši neskartās dabas dēļ īpaši piemērota sūnu ekoloģijas izpētei. Pašlaik bagātīgu sūnu sugu sastopamību uz pētītajiem substrātiem nodrošina koku sugas ar atšķirīgu mizas reakciju, dažāda garuma un apkārtmēra kritalas, heterogēns koku sugu sastāvs. Pēdējo 100 gadu laikā Moricsalas meža …
Item Response Trees: a recommended method for analyzing categorical data in behavioral studies
2015
Behavioral data are notable for presenting challenges to their statistical analysis, often due to the difficulties in measuring behavior on a quantitative scale. Instead, a range of qualitative alternative responses is recorded. These can often be understood as the outcome of a sequence of binary decisions. For example, faced by a predator, an individual may decide to flee or stay. If it stays, it may decide to freeze or display a threat and if it displays a threat, it may choose from several alternative forms of display. Here we argue that instead of being analyzed using traditional nonparametric statistics or a series of separate analyses split by response categories, this kind of data ca…
Brief interventions in counselling for nutrition and the prevalence of metabolic syndrome in primary care adult patients
2018
This research i) examined the influence of a brief nutrition-based intervention among primary care patients in changing nutrition and clinical values related to metabolic syndrome (study 1), and ii) assessed nutrition and the prevalence of metabolic syndrome and its clinical determinants among primary care patients in different sociodemographic groups (study 2). In study 1, a systematic literature review was conducted on eight databases during Sept.-Oct. 2016 with a final update in Nov. 2017. In study 2, data (n=557 for RO II-III, n=251 for RO IV-V) collected in primary care practices in Central Finland in 2006-2008 for the EVI study were analysed using Chi-Square test, GLM and Logistic Reg…
Data from: Predator mimicry, not conspicuousness, explains the efficacy of butterfly eyespots
2015
Large conspicuous eyespots on butterfly wings have been shown to deter predators. This has been traditionally explained by mimicry of vertebrate eyes, but recently the classic eye-mimicry hypothesis has been challenged. It is proposed that the conspicuousness of the eyespot, not mimicry, is what causes aversion due to sensory biases, neophobia or sensory overloads. We conducted an experiment to directly test whether the eye-mimicry or the conspicuousness hypothesis better explain eyespot efficacy. We used great tits (Parus major) as model predator, and tested their reaction towards animated images on a computer display. Birds were tested against images of butterflies without eyespots, with …
Gaismas un trokšņa piesārņojuma ietekme uz meža pūces Strix aluco sastopamību gar urbanizācijas gradientu: piemērs no Rīgas Latvijā
2017
Darba mērķis ir noskaidrot, kādi urbānās vides faktori ir svarīgi meža pūces dzīvotnes izvēlē pilsētvidē, vai gaismas un trokšņa piesārņojumam ir būtiska ietekme. Pētījumā izmantotas plaši pieejamas tālizpētes metodes, kas sniedz iespējas šo metodiku pielietot plašos reģionos un veikt datu interpretāciju. Veiktas uzskaites Rīgas administratīvās teritorijas robežās pūču telpiskās izplatības datu iegūšanais. Ar tālizpētes metodēm analizēti gaismas piesārņojuma un zemes virsmas seguma dati. Veikta vispārināto lineāro modeļu analīze meža pūces sastopamības prognozēšanai. Apsekotajās 173 vienībās kostatēti 40 meža pūces atsaukšanās gadījumi. Noskaidrots, ka meža pūces sastopamību urbānā vidē vis…
Latvijas mežu platības pārmaiņu ietekme uz meža putnu izplatību un daudzveidību
2018
Darbā salīdzinātas otrā Latvijas ligzdojošo putnu atlanta (2000-2004) un Eiropas ligzdojošo putnu atlanta (2013-2017) laikā konstatētās meža putnu sugas – to daudzveidība un izplatība. Lai noteiktu salīdzināmās teritorijas (5x5 km kvadrātus), izveidoti divi vispārinātie lineārie modeļi. Kopējā sugu daudzveidība starp atlantiem nav mainījusies, bet speciālistu daudzveidība pieaugusi par 0,6 sugām kvadrātā. Izplatība būtiski pieaugusi 12 un samazinājusies deviņām meža sugām. Izmantojot CORINE Land cover datus, noskaidrots, ka Latvijā ar mežu klātā platība samazinājusies par 11%. Multinomiālās regresijas izskaidrotā variācija bija maza, tomēr konstatēts, ka vismaz četru sugu izplatību būtiski …