Search results for "sarjat"
showing 10 items of 70 documents
Deflation-based separation of uncorrelated stationary time series
2014
In this paper we assume that the observed pp time series are linear combinations of pp latent uncorrelated weakly stationary time series. The problem is then to find an estimate for an unmixing matrix that transforms the observed time series back to uncorrelated time series. The so called SOBI (Second Order Blind Identification) estimate aims at a joint diagonalization of the covariance matrix and several autocovariance matrices with varying lags. In this paper, we propose a novel procedure that extracts the latent time series one by one. The limiting distribution of this deflation-based SOBI is found under general conditions, and we show how the results can be used for the comparison of es…
Kylmän sodan Suomi, suomalaiset ja suomettuminen
2022
Televisioformaatti ja kulttuurinen neuvottelu
2019
Televisioformaatit ovat kulkeneet mukanani jo yli kymmenen vuoden ajan – välillä päätoimisen tutkimustyön kohteena, välillä sivujuonteena muiden töiden lomassa ja usein myös osana omaa katsomiskokemustani. Ensimmäisen kerran törmäsin formaatteihin, kun keräsin aineistoa televisiohistoriaa käsittelevää väitöstutkimustani varten. Viitteitä lisensoimattomista ohjelmakopioista tuli vastaan useissa eri lähteissä, mutta varhaisin virallisesti Suomeen hankittu ohjelmaformaatti löytyi yllättäen Ylen arkistosta. kun väitökseni jälkeen pääsin vihdoin jäljittämään Tenavatuokion historiaa, syntyi ajatus televisioformaatista kulttuurisena neuvotteluna. Lopulta tämä ajatus laajeni kolmivuotiseksi tutkimu…
Affective Estrangement and Ecological Destruction in TV Crime Series Fortitude
2020
Koistinen and Mäntymäki examine how graphic violence evokes affect in the context of ecological destruction in the UK-produced TV crime fiction series Fortitude (2015–17). They argue that the series mobilises generic exchange by incorporating speculative elements into a traditional crime narrative structure, thereby creating space for affective estrangement. They show how the amalgamation of violence, ecological destruction and affect serves as an entrance into socioecological critique with a strong cautionary element through the negotiation between the human and nonhuman and the ethics of violence. Theoretically, the chapter relies on Sara Ahmed’s view of affect as social processes produce…
A Deep Learning Model for Automatic Sleep Scoring using Multimodality Time Series
2021
Sleep scoring is a fundamental but time-consuming process in any sleep laboratory. Automatic sleep scoring is crucial and urgent to help address the increasing unmet need for sleep research. Therefore, this paper aims to develop an end-to-end deep learning architecture using raw polysomnographic recordings to automate sleep scoring. The proposed model adopts two-dimensional convolutional neural networks (2D-CNN) to automatically learn features from multi-modality signals, together with a "squeeze and excitation" block for recalibrating channel-wise feature responses. The learnt representations are finally fed to a softmax classifier to generate predictions for each sleep stage. The model pe…
A Bayesian Reconstruction of a Historical Population in Finland, 1647–1850
2020
This article provides a novel method for estimating historical population development. We review the previous literature on historical population time-series estimates and propose a general outline to address the well-known methodological problems. We use a Bayesian hierarchical time-series model that allows us to integrate the parish-level data set and prior population information in a coherent manner. The procedure provides us with model-based posterior intervals for the final population estimates. We demonstrate its applicability by estimating the long-term development of Finlands population from 1647 onward and simultaneously place the country among the very few to have an annual popula…
Effects of density, species interactions, and environmental stochasticity on the dynamics of British bird communities
2022
Our knowledge of the factors affecting species abundances is mainly based on time-series analyses of a few well-studied species at single or few localities, but we know little about whether results from such analyses can be extrapolated to the community level. We apply a joint species distribution model to long-term time-series data on British bird communities to examine the relative contribution of intra- and interspecific density dependence at different spatial scales, as well as the influence of environmental stochasticity, to spatiotemporal interspecific variation in abundance. Intraspecific density dependence has the major structuring effect on these bird communities. In addition, envi…
Aikasarjamallit apuna Suomen talouden seurannassa
2019
Viimeisten vuosikymmenien aikana kansainvälisessä ekonometrisessa tutkimuskirjallisuudessa on esitetty useita makrotaloudellista tilaa kuvaavien muuttujien informaatiota yhdistäviä lyhyen aikavälin mallinnus- ja ennustemenetelmiä. Näitä ns. nowcasting-menetelmiä on myös onnistuneesti hyödynnetty ja sovellettu Suomen talouden seurantaan. Tässä artikkelissa esittelemme katsauksen monella taholla tehtyyn kehitystyöhön ja näiden hankkeiden yhteydessä saatuihin tuloksiin Suomen aineiston tapauksessa. Suomen taloutta koskevien suhdanneindeksien hyödyntämisen myötä suhdanteiden käännepisteiden määrittäminen on tarkempaa ja käännepisteiden tuottamia taantumajaksoja voidaan vastaavasti ennustaa binä…
A review of second‐order blind identification methods
2022
Second order source separation (SOS) is a data analysis tool which can be used for revealing hidden structures in multivariate time series data or as a tool for dimension reduction. Such methods are nowadays increasingly important as more and more high-dimensional multivariate time series data are measured in numerous fields of applied science. Dimension reduction is crucial, as modelling such high-dimensional data with multivariate time series models is often impractical as the number of parameters describing dependencies between the component time series is usually too high. SOS methods have their roots in the signal processing literature, where they were first used to separate source sig…
Tale(s) of a forest – re-creation of a primeval forest in three environmental narratives
2020
We analyze three environmentally conscious works that are concerned with the state of Finnish forests: the documentary film Metsän tarina/Tale of a Forest (2012), the book with the same name (2013) and the series of short documentaries Tarinoita metsästä/Tales from the Forest (2013). By combining methods from arts research and ecology, we ask how the narratives adapt material from nature photography. The film and book present mythic stories and old Finnish beliefs about forests. They also contain references to cultural memory. Additionally, the biodiversity on display reflects a conventional practice to exhibit large or charismatic species. However, the ecological message remains only impli…