Browsing by Title

The economic development of Northern Ostrobothnia has been in the spotlight because of rapid growth of Oulu high-technology industries. However, most of the researchers seem to concentrate on the development in Oulu without considering the situation in the whole region or its peripheries. The thesis gives an overview of the main factors that affected successful high-tech development in Oulu since 1960s as well the economic and social development in the whole region of Northern Ostrobothnia. Innovations have become a very topical issue in research and policies during the last decades. For this reason the understanding of this term has become vague and they started to be used as buzzwords more and more often. This thesis analyses how innovations are defined in the regional strategic programmes of Norhern Ostrobothnia, what types of innovation activities are emphasized most, which industries are considered as benefiting from innovations. The usage of different territorial innovation models (innovative milieu, cluster, regional innovation system) is also analyzed. The research also examines how different geographical scales of innovation activities are seen in the studied policy documents: how the role of global scale for innovative development in Northern Ostrobothnia is understood, are there any links with national innovation system discussed, how are innovations on local scales treated. The documents chosen for the research are regional strategic programmes for four programming periods: 2004-2006, 2007-2010, 2011-2013 and 2014-2017. The data is analyzed using qualitative content analysis, which allows to systematize and summarize the content of the text and examine in what contexts are the terms used. The analytical approach is theory-driven, however, modified with consideration to the data. The research showed that regional strategic programmes employ broad definition of innovation, especially emphasizing marketing in the documents for the latest programming periods. Innovative activities are regarded not only in context of high-technology industries, but in relation to low- and medium-technology industries as well, though in latest documents the focus is mainly on high-tech production. The term 'cluster' is used mainly as a buzzword, though in the latest regional strategic programme the frequency of use has decreased, alternatively the model of innovative milieu has become more popular. Concept of regional innovation system has been briefly mentioned in the documents. There has been very limited explanation of structures of any of the territorial innovation models, however, the documents linked the concept of regional innovation system to innovative milieu, seeing the first as a next stage of development of the latter. Regional strategic programmes mention the role of innovation processes happening on different geographical levels, but the discussion is rather limited - international scale is mostly considered as global market, national scale is seen as the source of funding and on local scale the attention is mainly payed to Oulu.

The goal of the thesis is to prove the Dold-Kan Correspondence, which is a theorem stating that the category of simplicial abelian groups sAb and the category of positively graded chain complexes Ch+ are equivalent. The thesis also goes through these concepts mentioned in the theorem, starting with categories and functors in the first section. In this section, the aim is to give enough information about category theory, so that the equivalence of categories can be understood. The second section uses these category theoretical concepts to define the simplex category, where the objects are ordered sets n = { 0 -> 1 -> ... -> n }, where n is a natural number, and the morphisms are order preserving maps between these sets. The idea is to define simplicial objects, which are contravariant functors from the simplex category to some other category. Here is also given the definition of coface and codegeneracy maps, which are special kind of morphisms in the simplex category. With these, the cosimplicial (and later simplicial) identities are defined. These identities are central in the calculations done later in the thesis. In fact, one can think of them as the basic tools for working with simplicial objects. In the third section, the thesis introduces chain complexes and chain maps, which together form the category of chain complexes. This lays the foundation for the fourth section, where the goal is to form three different chain complexes out of any given simplicial abelian group A. These chain complexes are the Moore complex A*, the chain complex generated by degeneracies DA* and the normalized chain complex NA*. The latter two of these are both subcomplexes of the Moore complex. In fact, it is later on shown that there exists an isomorphism An = NAn +DAn between the abelian groups forming these chain complexes. This connection between these chain complexes is an important one, and it is proved and used later on in the seventh section. At this point in the thesis, all the knowledge for understanding the Dold-Kan Correspondence has been presented. Thus begins the forming of the functors needed for the equivalence, which the theorem claims to exist. The functor from sAb to Ch+ maps a simplicial abelian group A to its normalized chain complex NA*, the definition of which was given earlier. This direction does not require that much additional work, since most of it was done in the sections dealing with chain complexes. However, defining the functor in the opposite direction does require some more thought. The idea is to map a chain complex K* to a simplicial abelian group, which is formed using direct sums and factorization. Forming it also requires the definition of another functor from a subcategory of the simplex category, where the objects are those of the simplex category but the morphisms are only the injections, to the category of abelian groups Ab. After these functors have been defined, the rest of the thesis is about showing that they truly do form an equivalence between the categories sAb and Ch+.

Within the last century humanity has grown significantly more numerous and more globally connected than ever before in its history. Together with the increased risks of climate change, we are more susceptible than ever to major epidemics and pandemics caused by novel zoonotic diseases. For these reasons it is not only important understand under which conditions novel pathogens are able to invade and spread in a host population but also to understand how these pathogens can be eradicated following an invasion event. In this thesis we present and study the demographic and evolutionary dynamics of a compartmental epidemiological model that includes a compartment for asymptomatic individuals, who require a second infection to become symptomatic and infectious. We show that the model exhibits a wide variety of demographic dynamical behaviour, all of which can be evolutionarily attracting configurations under simple evolutionary considerations. The model is an extreme simplification of the real world and excludes relevant information such as age and spatial structures of the population at hand. The aim of this thesis is to obtain a general understanding of how varying certain parameters on one hand allows a pathogen to invade a host population and, on the other hand, allows the host to eradicate an established pathogen, in particular, through the process of evolution.

Tutkielman tavoitteena on esitellä ja konstruoida Stone–Čech kompaktisointi täysin säännöllisille avaruuksille. Tutkielmassa esitellään myös uniforminen avaruus ja käsitellään tämän yhteyttä pseudometriikoihin. Tutkielman alussa käydään läpi käytettäviä topologiaan ja joukkomerkintöihin liittyviä käsitteitä ja merkintätapoja. Lukijan oletetaan tuntevan yleisen topologisen avaruuden määritelmä ja tähän liittyviä perustuloksia. Peruskäsitteiden jälkeen esitellään uniforminen avaruus, eli topologinen avaruus, johon on lisätty uniforminen rakenne. Tämä rakenne mahdollistaa muun muassa täydellisyyden ja tasaisen jatkuvuuden määrittelyn ilman metriikkaa. Hausdorff uniformisoituvalle avaruudelle, eli täysin säännölliselle avaruudelle voidaan konstruoida Stone–Čech kompaktisointi. Tässä tutkielmassa Stone–Čech kompaktisointi konstruoidaan käyttäen upotusta yksikkövälien tuloon. Tulos voitaisiin konstruoida yhtäpitävästi myös muilla tavoilla, muun muassa ultrafilttereillä tai C*-algebroilla. Näitä muita tapoja emme kuitenkaan tässä työssä käsittele.

The Criegee intermediates (CIs) have been the topic for several studies and their role in global atmospheric chemistry is becoming better understood. Isoprene and monoterpenes form a large portion of the total biogenic volatile organic compound emissions in the forested regions of the world, isoprene being the most abundant non-methane hydrocarbon in the Earth's atmosphere. The carbon-carbon double bonds in these compounds are efficiently ozonized (the reaction where an unsaturated compound reacts with ozone) in the atmosphere leading to primary ozonides that subsequently decompose into Criegee intermediates and carbonyl compound molecules. Approximately 50 % of the CIs derived from acyclic alkenes immediately decompose in unimolecular reactions forming, e.g., hydroxyl radicals, the most important oxidizing species in the Earth’s atmosphere. The remainder is stabilized in atmospheric conditions in collisions with other molecules and are subsequently called stabilized Criegee intermediates (sCI). The sCI yields are often smaller, around 20 %, for Criegee intermediates formed in ozonolysis of cyclic alkenes, such as α-pinene. These sCIs can further react with atmospheric constituents (H2O, (H2O)2, SO2, NO2, organic acids etc.) in bimolecular reactions or decompose/isomerize in unimolecular reactions. The bimolecular reactions of sCIs with SO2 contribute significantly to the formation of atmospheric gas phase sulphuric acid and as such are an important factor in nucleation and formation of clouds. In the lower atmosphere, H2SO4 also has adverse health effects on humans and animals and causes corrosion of building materials. Additionally, unimolecular decay and bimolecular reactions of sCIs produce OH radicals. The experimental studies done so far have largely focused on the few simplest sCIs, i.e., formaldehyde oxide (H2COO), acetaldehyde oxide (CH3COO), and acetone oxide ((CH3)2COO). The studies on more complex sCIs, such as methyl vinyl ketone oxide and sCIs formed via ozonolysis of terpenes, are mostly done computationally. The literature review part of this work presents the basic mechanisms of formation and natural removal of sCIs as well as results of recent direct kinetic studies of sCIs with focus on the simplest ones (CH2OO, CH3CHOO, and (CH3)2COO). The methods of detection used in experimental studies are also considered. The experimental section concentrates on measurements of unimolecular decay kinetics of acetone oxide (CH3)2COO above and below room temperature using a new photolytic precursor (CH3)2CIBr. In the experimental section also the apparatus utilized in the research is presented along with the modifications and improvements made on the setup in this work. The calibrations done to ensure accurate measurements are also presented.

Genome-wide association studies have identified hundreds of genomic loci associated with a wide range of human conditions and quantitative traits, such as cholesterol level and diabetes. However, most of these studies have focused on analysing single traits, even the studies involving multiple related traits. Growing evidence for pleiotropy, where the same genetic locus is associated with multiple traits, supports the idea that multivariate methods could provide a remarkable boost in statistical power compared to univariate methods. In this thesis the main research question is to compare the multivariate Wald test to the corresponding univariate test, and to see when multivariate testing is more useful. My second research question is to compare the multivariate Wald test and another multivariate method called Canonical Correlation Analysis (CCA), and to see if they yield the same result. To examine these topics I performed a simulation study in which I simulated data set with 1,000 genotypes and 1,000 individuals. In addition I simulated bivariate phenotypes that were differently correlated with each other, and the genotypes. I performed the univariate Wald test for each trait against each genotype, and the multivariate Wald test for each trait pair against each genotype. I also performed the corresponding CCA to compare those results with the Wald test. In addition to the simulation study I performed the similar analyses for real data from The National FINRISK Study. I used three different blood lipid measurements, HDL-cholesterol, LDL-cholesterol and triglycerides as example traits, and 157 genomic loci previously known to associate with blood lipid levels. These blood lipid levels were appropriate example traits for this study because they are correlated differently with each other, and they are differently associated with the 157 genomic loci used here. Therefore I found many different combinations of correlation between traits, and directions of genetic effects for different traits. Based on my simulation studies I can say that the multivariate testing is never much worse in terms of power to detect associations than the corresponding univariate tests, and in some cases it is much more powerful. Thus there is no reason not to do the multivariate analysis first in case of studying multiple related traits. Multivariate testing is more powerful in cases where the correlation between the traits is large and the genetic effects for the traits show opposite directions compared to the trait correlation. The least effective multivariate testing is compared to univariate testing when the correlation between the traits is small, and the directions of genetic effects is consistent with the trait correlation. Based on my results multivariate Wald test and CCA yield the same results, with some minor approximation differencies in small sample sizes.

I arbetet undersöker vi ett nytt och relativt outforskat område inom den matematiska analysen kallat universalitet. Idén är att utgående från ett enda element och med hjälp av någon divergerande eller "kaotisk" process approximera en hel klass med element. Mer formellt kan processen ses som en familj av kontinuerliga avbildningar från ett rum X till ett rum Y. Om det existerar ett sådant element i X att familjen avbildar detta till en tät mängd i Y kallas detta element för ett universellt element och familjen för en universell familj. I arbetet definierar och undersöker vi universalitetens egenskaper, olika exempel på universalitet, samt en förenklad version av universalitet kallad hypercyklicitet och det till universalitet nära förknippade fenomenet topologisk transitivitet. Till slut visar vi även hur teorin via den topologiska transitiviteten även är kopplad till de dynamiska systemens kaosteori.

This thesis is an investigation of unsupervised learning for image classification. The state-of-the-art image classification method is Convolutional Neural Network (CNN), which is a purely supervised learning method. We argue that despite of the triumph of supervised learning, unsupervised learning is still important and compatible with supervised learning. For example, in the situation where some classes have no training data at all, so called zero-shot learning task, unsupervised learning can leverage supervised learning to classify the images of unseen classes. We proposed a new zero-shot learning method based on CNN and several unsupervised learning algorithms. Our method achieves the state-of-the-art results on the largest public available labelled image dataset, ImageNet fall2011.

In this thesis, a novel method for linking scientific articles to taxonomy terms in the domain of food systems research is presented. With food systems being in the center of 12 of the 17 United Nations Sustainable Development goals, there has been an ever-growing amount of scientific articles in this field. These articles are vital in understanding the complex nature of food systems and their inter-dependencies. However, finding relevant literature in this field is difficult for decision makers given the interdisciplinary nature of the field and that annotation and expert feedback is expensive. In the thesis, BERT-based models (SBERT, SPECTER and SciBERT) are adapted to the food systems area and fine-tuned for tasks such as text classification and text similarity, which represents a solution to the problem of finding relevant articles in the food systems domain. The proposed search system uses several taxonomies and data augmentation to achieve the results, which are visualized in a created website. Linking food systems research articles to taxonomy terms shows good accuracy, with models finetuned on domain data achieving better performance on classification task. The best fine-tuning strategy for SPECTER and SciBERT is the combination of domain adaptation and classification. Fine-tuning for text similarity for SBERT improves SBERT performance only slightly. The proposed method can be used in other domains than food systems.

Tutkimuksessa pohdittiin kellumiseen ja uppoamiseen liittyvien ennakkokäsitysten hyödyntämisen mahdollisuuksia nosteen opetuksessa. Oppimisen tavoitteiden kannalta validien ennakkokäsitysten lisäksi pohditaan myös virhekäsitysten hyödyntämistä. Tässä tutkimuksessa tutkittaville 50 oppilaalle suoritettiin ennakkokäsitystesti, jonka jälkeen haastateltiin yhdeksää oppilasta. Haastattelut olivat kahden keskisiä opetustilanteita, joissa keskustelu aloitettiin oppilaan lomakevastauksien ja vastausten perusteluiden pohtimisesta. Keskustelua vietiin eteenpäin kysymysten ja havainnollistavien esimerkkien avulla. Oppilaan käsityksiä nosteesta pyrittiin siis kehittämään oppilaan lähtökohdat huomioon ottaen. Tämän tutkimuksen perusteella yläkouluikäiset voidaan luokitella karkeasti kolmeen ryhmään ennen nosteen opetusta. Haastavimmat oppilaat selittävät nostetta fysikaalisen painon avulla; painava kappaleet uppoavat ja kevyet kelluvat. Tässä ryhmässä noste saatettiin jopa nähdä väliaineen vastuksen kaltaisena vastusvoimana, jolloin esim. väliaineen viskositeetti tai väliaineeseen asetetun kappaleen terävyys vaikuttaa kellumiseen. Keskimmäinen ja suurin ryhmä ovat oppilaat, jotka selittivät nostetta ominaispainon avulla. Selityksellä pärjää jo monissa tilanteissa, mutta siitä puuttuvat käsitteet massa, tilavuus ja tiheys sekä paino ja noste fysikaalisina voimina. Osa keskimmäisen ryhmän oppilaista omaa selityksen nosteen aiheuttajalle; maa vetää väliainetta joko kovempaa tai hiljempaa kuin väliaineessa olevaa kappaletta. Opetuksen kannalta vaivattomin ryhmä ovat oppilaat, jotka käyttivät päättelyissään fysikaalisia suureita kuten massa, tilavuus ja tiheys. Nämä oppilaat ymmärsivät myös, että noste syntyy paineesta, mutta paine-eron käsite ei ollut heilläkään käytössä. Virhekäsitystestin perusteella tavallisin virhekäsitys oppilailla oli kappaleen pinta-alan yhdistäminen nosteen suuruuteen; kappale kelluu helpommin mikäli paino on jakautunut suuremmalle alalle. Nesteellä on siis jonkinlainen kelluttavat ominaisuus, joka on levittäytynyt sen pinnalle. Kyseinen virhekäsitys ei ole täysin huono, sillä noste on paineesta syntyvä voima ja paineesta syntyvät voimat riippuvat usein pinta-alasta. Virhekäsitys häviää, jos oppilas oppii ymmärtämään nosteen syntymekanismia paremmin. Pinta-alan ja paine-eron välisen yhteyden oppiminen vaatii ymmärrystä siitä, että noste syntyy kappaleen ylä- ja alapuolen välisestä paine-erosta. Kun kappaleen pinta-ala kasvaa, paine-ero pienenee. Kolme haastateltua oppilasta olivat valmiita vastaanottamaan edellä mainitun päättelyn heidän omista lähtökohdistaan. Ennakkokäsitystesti synnytti tai toi esiin myös paljon muita virhekäsityksiä. Tämä johtui osittain siitä, että testin kysymyksissä esiintyi tarkoituksella ominaisuuksia, jotka intuitio saattaa yhdistää uppoamiseen ja kellumiseen. Oppilaat tukivat perusteluitaan näillä konkreettisilla ominaisuuksilla huolimatta siitä, että jokaisesta kysymyksestä pystyi päättelemään minkälainen kysytyn kappaleen tiheys on. Tiheyden sijaan perustelut oli helpompi muotoilla mm. kappaleen painon, kaasupitoisuuden, reikäisyyden, litteyden, terävyyden, asennon, kovuuden, täytemateriaalin, väliaineen määrän ja väliaineen viskositeetin perusteella. Tämän työn tulokset osoittavat että on vaikea tunnistaa, missä vaiheessa ja miten ennakkokäsitykset syntyvät. Perinteisesti on ajateltu että ennakkokäsitykset syntyvät opetusta edeltävistä havainnoista ja sosiaalisesta vuorovaikutuksesta. Osa ennakkokäsityksistä saattaa kuitenkin syntyä vasta opetustilanteessa. Virhekäsityksiä ei tarvitse kauhistella, sillä ne saattavat olla oppilaan ensimmäisiä yrityksiä ratkaista jokin fysikaalinen ongelma tieteellisessä kontekstissa.