Search results for "sarja"

Norm-inflation results for purely BBM-type Boussinesq systems

2022

This article is concerned with the norm-inflation phenomena associated with a periodic initial-value abcd-Benjamin-Bona-Mahony type Boussinesq system. We show that the initial-value problem is ill-posed in the periodic Sobolev spaces H−sp (0, 2π)×H−sp (0, 2π) for all s > 0. Our proof is constructive, in the sense that we provide smooth initial data that generates solutions arbitrarily large in H−sp (0, 2π) × H−sp (0, 2π)-norm for arbitrarily short time. This result is sharp since in [15] the well-posedness is proved to holding for all positive periodic Sobolev indexes of the form Hsp (0, 2π) × Hsp (0, 2π), including s = 0. peerReviewed

‘Something’s Not Right in Silverhöjd’: Nordic Supernatural and Environmental and Species Justice in Jordskott

2022

In the Swedish/Finnish/British/Norwegian television series Jordskott (2015–17) child victims’ mysterious disappearances signal that ‘something’s not right’ in Silverhöjd, a Swedish town. Three detectives uncover a conflict between the locals who depend on a local industry and preternatural human-like but non-human forest creatures familiar from Nordic tradition and fairylore. Both humans and semi/non-humans are ambivalent, but what sets the latter apart is their implication in caring for nature, protecting it, and punishing those who harm it. We analyse this series’ instantiation of a folkloristic popular green criminology, based in the idea that popular discourses’ representations of crime…

Reimagining cultural memory of the arctic in the graphic narratives of Oqaluttuaq

2021

The Greenlandic oral story-telling tradition, Oqaluttuaq, meaning “history,” “legend,” and “narrative,” is recognized as an important entry point into Arctic collective memory. The graphic artist Nuka K. Godtfredsen and his literary and scientific collaborators have used the term as the title of graphic narratives published from 2009 to 2018, and focused on four moments or ‘snippets’ from Greenland’s history (from the periods of Saqqaq, late Dorset, Norse settlement, and European colonization). Adopting a fragmentary and episodic approach to historical narrativization, the texts frame the modern European presence in Greenland as one of multiple migrations to and settlements in the Artic, ra…

Integrated capital shares

2019

In empirical macroeconomics, inter-dependencies between countries are often analysed using cross-country correlations or graphical investigation of time series. This study shows that applying an alternative methodological approach - identification of common unobservable factors and using them as explanatory variables for country-specific time series - indicates a stronger cross-country integration of functional income distributions than the standard methods. The results vary only little between different samples, where both the country and year coverage change. Moreover, the main findings are not sensitive to the way capital depreciation is taken into account. The primary driving factor see…

Blind recovery of sources for multivariate space-time random fields

2022

AbstractWith advances in modern worlds technology, huge datasets that show dependencies in space as well as in time occur frequently in practice. As an example, several monitoring stations at different geographical locations track hourly concentration measurements of a number of air pollutants for several years. Such a dataset contains thousands of multivariate observations, thus, proper statistical analysis needs to account for dependencies in space and time between and among the different monitored variables. To simplify the consequent multivariate spatio-temporal statistical analysis it might be of interest to detect linear transformations of the original observations that result in stra…

Mixture Hidden Markov Models for Sequence Data: The seqHMM Package in R

2019

Sequence analysis is being more and more widely used for the analysis of social sequences and other multivariate categorical time series data. However, it is often complex to describe, visualize, and compare large sequence data, especially when there are multiple parallel sequences per subject. Hidden (latent) Markov models (HMMs) are able to detect underlying latent structures and they can be used in various longitudinal settings: to account for measurement error, to detect unobservable states, or to compress information across several types of observations. Extending to mixture hidden Markov models (MHMMs) allows clustering data into homogeneous subsets, with or without external covariate…

KFAS : Exponential Family State Space Models in R

2017

State space modelling is an efficient and flexible method for statistical inference of a broad class of time series and other data. This paper describes an R package KFAS for state space modelling with the observations from an exponential family, namely Gaussian, Poisson, binomial, negative binomial and gamma distributions. After introducing the basic theory behind Gaussian and non-Gaussian state space models, an illustrative example of Poisson time series forecasting is provided. Finally, a comparison to alternative R packages suitable for non-Gaussian time series modelling is presented.

Efficient Bayesian generalized linear models with time-varying coefficients : The walker package in R

2020

The R package walker extends standard Bayesian general linear models to the case where the effects of the explanatory variables can vary in time. This allows, for example, to model the effects of interventions such as changes in tax policy which gradually increases their effect over time. The Markov chain Monte Carlo algorithms powering the Bayesian inference are based on Hamiltonian Monte Carlo provided by Stan software, using a state space representation of the model to marginalise over the regression coefficients for efficient low-dimensional sampling.

Sarjakuva suomalaisen yhteiskunnan peilinä : Ola Fogelbergin Pekka Puupää-sarjakuva Kuluttajain Lehdessä 1925-1952

2001

Fourier'n sarjan suppeneminen

2017

Funktion f Fourier'n sarja on ääretön funktiosarja, jossa summataan funktiosta f ja summausindeksistä n riippuvia Fourier'n kertoimia funktiolla e^{inx} kerrottuna. Fourier'n sarjoja käytetään esimerkiksi osittaisdifferentiaaliyhtälöiden ratkaisemiseen. Tässä tutkielmassa käsitellään Fourier'n sarjan suppenemista. Kun Fourier'n sarja keksittiin, pitkään luultiin, että jatkuvan funktion Fourier'n sarja suppenee aina. Tässä työssä osoitetaan, että näin ei ole. Ensin työssä osoitetaan, että jatkuvan funktion Fourier'n sarja "melkein suppenee," eli on Abel- ja Cesàro-summautuva. Abel-summautuvuudessa sarjan summattavat kerrotaan luvulla r^n, missä luku r on itseisarvoltaan pienempi kuin 1 ja n …