Browsing by Title
Now showing items 3748-3767 of 4026
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(2013)The purpose of this thesis is to study the asymmetric simple exclusion process, its asymptotics and some connections to other stochastic models. The text begins by giving some results on random matrix theory, such as the distribution function of the largest eigenvalue of a given random matrix. This is followed by a short section on the totally asymmetric simple exclusion process, which is a stochastic model of fermionic particles jumping only in one direction on a one-dimensional lattice. The probability that a given particle has jumped m times is then shown to be equal to the distribution of the largest eigenvalue of a specific type of a random matrix analyzed earlier. As this hints at some kind of universality, the particle model is then generalized to the asymmetric simple exclusion process, in which the particles can jump left or right. It turns out this model does not have the simple determinantal structure the earlier models had. The asymptotics of the model will then be analyzed, and it turns out there is a large universality class that encompasses all the models analyzed in the text. The reader is expected to be familiar with basic measure theory and complex analysis.
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(2018)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.
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(2014)Unkarin koulujärjestelmä ei eroa paljon Suomen järjestelmästä. Oppivelvollisuus kestää 18-vuotiaaksi ja julkinen valtion ylläpitämä koulutus on maksutonta. Lisäksi on yksityisiä kouluja. Kömal on vuonna 1984 perustettu unkarilainen matematiikkalehti, joka järjestää kuukausittain matematiikkakilpailuja unkarilaisille koululaisille. Kilpailutehtävistä löytyy Kömalin verkkosivulta englanninkieliset käännökset, ja ne ovat kaikkien saatavilla. Suomessa matematiikkakilpailut eivät ole yhtä suosittuja kuin Unkarissa, mutta tarjolla on sekä kansallisia että kansainvälisiä kilpailuja. Tähän työhön olen suomentanut 116 kilpailutehtävää eri vuosilta. Kaikki tehtävät ovat kilpailun helpoimmasta kategoriasta. Ainakin tässä kategoriassa oli eniten geometrian tehtäviä. Tehtävien luokittelu eri aihealueisiin ei kuitenkaan ollut aina helppoa, sillä lähes kaikkien tehtävien ratkaisemiseen tarvitaan osaamista useilta matematiikan osa-alueilta. Analysoimieni tehtävien perusteella unkarilaiset matematiikan tehtävät ovat haastavampia ja moniulotteisempia kuin suomalaiset tehtävät. Suomessa matematiikka pilkotaan osa-alueisiin, joiden välinen yhteys saattaa jäädä epäselväksi. Unkarilaisen mallin mukaan matematiikka on yksi iso kokonaisuus, jossa kaikki palaset liittyvät toisiinsa. Analysoimani tehtävät olivat kilpailutehtäviä, eivätkä siis välttämättä vastaa unkarilaisten oppikirjojen tehtäviä. Kaikki analysoimani tehtävät ovat kilpailun helpoimmasta kategoriasta, jossa nuorin kilpailijaryhmä luokille 1-8 eli 6-14-vuotiaille oppilaille. Näistä suurin osa tehtävistä on mielestäni liian haastavia suomalaisille peruskoululaisille, tietysti kilpailuun osallistuminen ylipäätään edellyttää matemaattista harrastuneisuutta.
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(2016)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.
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(2023)The objective of this thesis was to explore the article corpus of a domain-specific Finnish-language newspaper to generate a new content tag word set to replace an existing one of poor quality. The articles used as the dataset in this study had previously human-assigned content tags, but in absence of a proper tagging strategy and guidelines, the assigned tags were found to include too much variation to be useful, e.g., as search terms. No supervised learning models were used, since there was no good quality training material available specific to the topics of the data. Instead, we experimented in generating new tagsets with two unsupervised methods alongside a few variations based on nouns and proper nouns in the text content of the articles. A proper tag set would be useful in tagging future articles automatically or in drafting guidelines for manual tagging of future articles by the journalists. A limited survey among subject matter experts and other responders was conducted in order to evaluate the results generated by the methods. In general, the results were not encouraging, with the most basic model TF-IDF clearly performing better than the other models across all responders. Further examination after topic modeling using Latent Dirichlet Allocation (LDA) revealed, that somewhat better scores could be found among some topics. A further manual task of assessing and naming of the topics followed by a new tagging effort within topics was suggested as a next step in order to overcome the deficiencies in the presented methods.
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(2022)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.
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(2014)In situ U–Pb zircon dating was done for the host rocks of the Juomasuo gold deposit, located in the Paleoproterozoic Kuusamo supracrustal belt, eastern Finland. For dating purposes, five samples were chosen to represent the typical volcano-sedimentary rock types of the deposit in their mineralized and unmineralized form. The samples were studied petrologically and dated using the LA–MC–ICP/MS technique at the research laboratory of the Geological Survey of Finland and the Finland Geoscience Laboratory (SGL). The U–Pb data revealed heterogenic detrital zircon populations even for the felsic volcanic rocks, and thus, all the samples were delineated as sedimentary/volcano-sedimentary sequences. The maximum deposition ages fall in the 2.75–2.65 Ga window, and not a single Paleoproterozoic age was measured in the bulk of 159 measurements. The pervasively altered samples from the mineralized sequence of the Juomasuo deposit hosted a younger population of homogenized, BSE-pale/CL-dark zircons and domains within zircon grains, with 2.62–2.60 Ga ages. This age can be linked to the Neoarchean crustal growth event at 2.7–2.6 Ga, described from the Archean terrains all over the world, including the Archean of the Karelia Province in Finland. Unfortunately, in the limits of this thesis, the homogenization age cannot be interpreted as the minimum depositional age of the studied metasedimentary rocks, as it remains unclear, whether the homogenization of the zircons took place before or after the deposition. Although the majority of the precursors of the studied supracrustal rocks from Kuusamo were presumably deposited between 2.43 and 2.21 Ga, there are no corresponding ages of volcanism in the area. The lack of U–Pb ages of that time frame is a global phenomenon, and the topic is thus pertinent to modelling of Paleoproterozoic plate tectonics. It may be that the Kuusamo supracrustal belt represents a deposition during a global slowdown in plate tectonics, thus recording an anomalous period in the history of planet Earth.
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(2014)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.
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(2018)The trending of urban living during recent years can be seen both in public debate and in growth statistics of cities. The most attractive areas in addition to regions’ central cities are those surrounding municipalities which have good transportation connections to the central city and have managed to highlight their urban features. The trend can clearly be seen in the city of Järvenpää, which was, with annual population growth of 2,5 %, the fastest growing municipality in continental Finland in 2016–2017. As the popularity of urban living is growing, the focus of construction in Järvenpää has shifted from traditional single-family and low-rise housing to apartment buildings located close to train stations. This Master’s thesis looks at the pull factors of the new urban residential areas in Järvenpää as well as factors encouraging to settle down in the areas. The reasons for moving to the areas are compared to current social, demographic and migration trends. The study addresses the residents' point of view to housing phenomena. The aim is to pay attention to the connections between household decision-making processes and broader migration phenomena. In addition, the aim is to supplement the field of housing and migration studies in Finland, in which the focus has been in the dynamics between the urban areas of the regional centers and the suburbs of the surrounding municipalities, while less attention has been payed to the differing characteristics of the surrounding areas. The research problem is approached through the following questions: who are the residents of the new residential areas located near train stations in Järvenpää; which factors most significantly guide the housing choices of these residents; and how do the residents’ housing pathways form regionally and structurally. The analysis and discussion are supported by the contextual framework of housing chains, developed in the theory section of the thesis. The data was collected through a survey in spring 2018. The survey was targeted to certain new areas close to the train stations of Järvenpää and Ainola. The survey was sent to altogether 1548 residents. 400 replies were received, which makes the response rate 26 %. Based on an analysis of possible non-response bias, the data was observed to be relatively representative to the population, apart from the elderly being somewhat overrepresented. The main analysis methods where statistical analyses (frequency analysis, cross tabulation and factor analysis) as well as content analysis of the open-ended questions. The data was mainly analyzed through comparisons of different kinds of residential areas as well as demographic groups. The results of the study can be summarized in three main points. Firstly, the new residential areas located near train stations in Järvenpää reflect broader social and demographic trends as well as current trends in housing . In the areas close to the city, majority of the residents live alone and are young adults or elderly. Similar to national trends, the housing preferences included single-family housing and peaceful living environment, but at the same time, services, central location and good transportation were valued. Secondly, the attractiveness of the area in all study areas was based on central location and good transportation and in the fact that the apartments were new. However, there were differences in the importance of services and nature when comparing the apartment building areas closest to the center and the apartment building areas and detached house areas farther from the center. Thirdly, it was observed that the areas not only bring new residents to the city, but also pull a notable amount of people to move within the city. The new areas thus connect to the existing housing stock and start vacancy chains by opening vacancies in both detached houses and older apartment buildings. Various housing chains also occurred in how the social contacts outside households, the stage of family life-cycle, previous experiences and values affect housing choices. Based on the results, it can be noted that successful urban apartment building housing in the surrounding municipalities is characterized by good commercial and public services and efficient transportation, whereas in detached housing, the desired environment is centrally and transportation-wise well located but peaceful and close to nature. The significance of the services and transportation in housing satisfaction should be acknowledged early on when planning and building new areas . Also, lifestyles and situations change, and that affects housing choices. The results indicate that diverse housing options will have demand alongside the high-rise building boom. Additionally, it is important to acknowledge the interrelations between new construction and the existing housing stock to avoid making simplified interpretations about the logic of growth sustained by the trend of urban living.
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(2020)The themes of this thesis are alternative, informal, and uncommercial cultural spaces, the scenes using the spaces, and the individual scene participants. The study’s frame is Helsinki between 2000–2019. The study combines relevant theoretical discussion from subculture research tradition and urbanism. The key concepts of the thesis are ‘scenes,’ a cultural definition of ‘subculture,’ ‘alternative cultural spaces,’ ‘DIY culture’ (‘do it yourself’), and ‘enclaves.’ The thesis presents Helsinki’s ‘DIY landscape’ to consist of interconnected actors—scene participants—who are part of a network that revolves around making, performing and facilitating music in a specific urban infrastructure—the city, Helsinki—and in which the alternative cultural spaces create physical ‘hubs’ for the scene. The data has been collected online via a combination of oral history recollections and qualitative surveying. The data was collected in collaboration between Helsinki City Museum and Music Archive Finland in fall 2019. The data consist of 70 individual responses. The data is treated through the epistemology of qualitative research and oral history, and therefore is seen to include both ‘factual’ information and the informant’s subjective interpretations, their experience. On a practical level, the analysis has been conducted mainly via qualitative content analysis (QCA), but also geographic information system (GIS) has been used. The study aims to explicate a widely recognized but poorly known cultural phenomenon. The study’s key results are as follows. Four types of alternative cultural spaces have existed: dedicated buildings, rooms, outdoor venues, and even a ship. All of the study’s 34 spaces have hosted live music events and a variety of other cultural, political, and social activities. The spaces have been acquired for use by renting, squatting, and asking permission, and in two cases are owned by the facilitator. With some exceptions, they are located in the fringe areas of Helsinki’s city center, have a relatively short lifespan (maximum of five years in a set location) and share ‘aesthetics of necessity’ that roots meager or non-existent funding and the use of subcultural symbols and art. The spaces follow certain ‘DIY operating principles’ that aim to create an encouraging and inclusive atmosphere for DIY participation. The spaces, and their users, have faced a variety of challenges, setbacks, and problems. These are rooted in funding, the deficits of the buildings and their facilities, and to other citizens, the police, and the City of Helsinki. The City’s role emerges from the data as ambivalent—a constrainer and enabler. According to the responder’s experience, the City does not have a uniform policy towards the use of vacant urban space, and DIY culture overall is not recognized. For the scenes, the alternative cultural spaces function as platforms where cherish—often ‘marginal’—music and subcultures. Some of the participants connect political and societal ideals to the spaces and DIY activities. DIY activities emerged as—sometimes self-purposefully—social and communal by their nature. In the spaces between scene participants take place socio-cultural ‘cross-fertilization,’ which sometimes leads to new organizational groups and even scenes forming. These might relocate their practices elsewhere, and thus DIY culture spreads to new locations in the urban infrastructure. For the individual scene participants, crossing with the scene represents an important part of finding a social reference group. Some of the responders described going through a ‘DIY phase,’ which is a several yearlong period in their youth when life orientations and identity are intensively connected to DIY culture. The meaningfulness of scene participation lasts to later life, even if the participant’s active years are foregone. For some, the skills and knowledge acquired in the scene creates a basis for a more professional career in cultural production. As the reasons for the diminish or end of the DIY participation are given the closure of an alternative cultural space focal for the participant, challenges in activities, and major life events. In the discussion, the thesis suggests the concept of ‘urban DIY enclaves’ in the toolboxes of urban planners and designers. The DIY enclaves differentiate from the broader urban landscape by their condition, aesthetics, political messages, and subcultural symbols. Socially they have been constructed to advance DIY culture and cherish the creative lifestyle associated with it. The concept is suggested as a device for acknowledging the existence of DIY culture; in other words, its need for space, and its participants’ eagerness to participate in the construction of the urban and cultural landscape.
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(Helsingin yliopistoHelsingfors universitetUniversity of Helsinki, 2009)Inadvertent climate modification has led to an increase in urban temperatures compared to the surrounding rural area. The main reason for the temperature rise is the altered energy portioning of input net radiation to heat storage and sensible and latent heat fluxes in addition to the anthropogenic heat flux. The heat storage flux and anthropogenic heat flux have not yet been determined for Helsinki and they are not directly measurable. To the contrary, turbulent fluxes of sensible and latent heat in addition to net radiation can be measured, and the anthropogenic heat flux together with the heat storage flux can be solved as a residual. As a result, all inaccuracies in the determination of the energy balance components propagate to the residual term and special attention must be paid to the accurate determination of the components. One cause of error in the turbulent fluxes is the fluctuation attenuation at high frequencies which can be accounted for by high frequency spectral corrections. The aim of this study is twofold: to assess the relevance of high frequency corrections to water vapor fluxes and to assess the temporal variation of the energy fluxes. Turbulent fluxes of sensible and latent heat have been measured at SMEAR III station, Helsinki, since December 2005 using the eddy covariance technique. In addition, net radiation measurements have been ongoing since July 2007. The used calculation methods in this study consist of widely accepted eddy covariance data post processing methods in addition to Fourier and wavelet analysis. The high frequency spectral correction using the traditional transfer function method is highly dependent on relative humidity and has an 11% effect on the latent heat flux. This method is based on an assumption of spectral similarity which is shown not to be valid. A new correction method using wavelet analysis is thus initialized and it seems to account for the high frequency variation deficit. Anyhow, the resulting wavelet correction remains minimal in contrast to the traditional transfer function correction. The energy fluxes exhibit a behavior characteristic for urban environments: the energy input is channeled to sensible heat as latent heat flux is restricted by water availability. The monthly mean residual of the energy balance ranges from 30 Wm-2 in summer to -35 Wm-2 in winter meaning a heat storage to the ground during summer. Furthermore, the anthropogenic heat flux is approximated to be 50 Wm-2 during winter when residential heating is important.
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(2022)As biodiversity loss is identified to be one of the pressing environmental challenges today, Finnish cities have begun to follow in the footsteps of many European cities by creating urban greening plans in the form of increasing meadow habitats. The ecological and economic benefits of urban meadows are well understood, but when meadow habitats are brought into people’s everyday environments, it is important to consider how it affects people’s environmental aesthetic experiences. ‘Aesthetics’ is often understood solely as individual preferences, but the aim of this thesis was to address the aesthetic appreciation of meadows through the field of environmental aesthetics. Combining the fields of environmental aesthetics and ecology, this study provides a fresh perspective to the value debate over urban meadows. The analysis of the work approached the topic from the perspective of Finnish cities. After compiling the operational programs that solely consider urban meadows, qualitative content analysis was used to analyze what ecological and aesthetic aspects are brought up in the documents and how they are valuated. To emphasize the aesthetic perspective, it was further investigated through discourse analysis whether there are consistent ways in which cities construct an image of the aesthetic values of urban meadows. The content analysis showed that the documents have both ecological and aesthetic viewpoints. The ecological content emphasized that meadows are important tool in increasing biodiversity and also provide recreational possibilities for people. The aesthetic content focused on the cultural-historical role of the meadows as well as the experiences provided by the meadows. Based on the content analysis, three uniform discourses were identified throughout the documents. The first relates to meadows which are the remains of cities’ agricultural history, and their cultural and ecological values are easily recognizable. The second refers to meadows that are currently emerging from other green types such as lawns and grasslands reverting to woodland. They are seen as having ecological and recreational value, but as they are unlikely to meet the expectations for flowering meadows, city officials want to inform citizens about the ecological qualities of these meadows to avoid negative feedback. The last discourse focuses on the experiential side of meadows, but instead of talking about the environmental aesthetic experience as understood in theoretical research, the argumentation is restricted to visual and recreational experiences. The way in which the aesthetic qualities, values and experiences of urban meadows are understood in a professional context reflects the way in which they are presented to the users of green areas. This thesis has revealed that the terminology used in the documents referring to environmental aesthetics is insufficient and does not correspond to the concepts presented in the theory of the work. Expanding the debate on environmental aesthetics would turn the goal of ‘people tolerating unordered ecosystems’ to ‘how can unordered ecosystems be aesthetically appreciated’. While informing citizens about the ecological benefits of urban meadows, they should also be informed about the potential aesthetic values of urban meadows, such as wildness, aesthetic diversity, and how the ordinary environment becomes extraordinary.
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(2014)Lagos is the biggest city not just in Nigeria but also in the Sub-Saharan Africa. This megacity has a reputation of being the most dangerous and chaotic city in the world. Despite that Lagos is facing an infrastructural crisis and most of the city acts through informal means, it has its own way to survive and operate. The purpose of this study is to create a picture of the urban structure of Lagos Metropolitan Area and compare it with the existing urban structure models. The purpose is also to discover the possible affects of existing zoning plans on the current structure and dynamism of the city. Again, the aim of this research is to study the characteristics of the metropolis and reflect them to the postmodern concepts of Myers's that intend to explain the nature of modern African cities. This study tries to provide new perspectives on the image of the study area. However, this study tries not to draw a detailed picture of every district of the metropolis but aims at highlighting the dominant features of the city. This study adopts qualitative research methods and is descriptive by its nature. The primary data consists of researches, maps, scientific articles, project documents and different kinds of publications concerning the for example landuse and dominant features of different districts and neighborhoods of Lagos. The data collected from these sources is combined and analyzed in order to create a visualization over the urban structure of Lagos. The secondary data was collected during the field trip in Lagos in 2009 and consists of observation notes. It serves as a supportive tool in the descriptive part of the work. The study concludes that the city structure in Lagos consists much of poor residential districts and slum areas. Most of the citizen live in poverty as medium- or high-grade districts do not exist nearly at all. Lagos is often described as industrial centre of Nigeria, but in reality the industrial activity is not particularly high since the weak infrastructure and low security situation of the city does not attract investors. Again, the structural analysis discovers that the city has currently just one clear core area. The large area of the metropolis would demand several central business districts to improve the mobility and selection of public services of the city. This study suggests that Lagos can be very easily described and expressed with the concepts presented by Myers. On the grounds of his concepts, Lagos has several features typical of modern African city. Colonial era has left its fingerprints both on the city structure and dynamics. The informal sector has a remarkable role in Lagos and violence is a constant part of the streets. Despite that, Lagos has slowly found its place among the global urban centres. Its significance as a centre of trade and culture keeps growing in the future. On the basis if this research it can be argued that there is a great need for urban structure studies in Africa. Often areas that appear as disorganized shantytowns include some structures and operating models of their own. By creating updated structure models and studies it is possible to affect positively on urban planning trends and also local development.
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(2023)With the growing concerns over data privacy and new regulations like the General Data Protection Regulation (GDPR), there has been increased attention to privacy-preserving synthetic data generation methods. However, the usability of these methods has received limited attention. This thesis focuses on the usability challenges associated with privacy-preserving synthetic data generation methods based on probabilistic graphical models. This thesis addresses usability challenges related to running time efficiency, applicability with continuous data and query selection with experiments conducted on different datasets. This thesis aims to bridge the gap between cutting-edge privacy-preserving synthetic data generation methods and their practical implementation with real-world datasets. Proposed solutions have the potential to make these methods more accessible and usable, thereby facilitating their broader adoption. The thesis concludes by summarizing the key results and emphasizing the importance of addressing usability challenges in privacy-preserving synthetic data generation methods.
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(2020)With the new trends in advanced healthcare equipment and innovation, the healthcare industry is now focused more on efficiency and improving quality. Devices record events in event log files that represent the program or application's actual usage. The log file of the event is like an operation history which shows what occurred in the program. Since devices have the log of real-time events, real-time processes can be tracked, and data analysed from different aspects. The details about the event log file can be used to create a process model and analyse the data to know its strengths and weaknesses. This thesis aimed to develop a tool for usability analysis used for GE healthcare. The design science approach has been used as an overall research method. To achieve the research goal, ideas was taken from already developed process mining algorithms and used in making algorithms that solves the problem of software process mining. In this thesis, already used process mining algorithm techniques were examined that can be used to answer the problem of software process mining. Software process mining was used to analyse the deployed software behavior. The study focused on making the process discovery algorithm along with structured algorithm. The outcome of the thesis was the tool that was used by the GE Healthcare to do the usability analysis on log files. The tool produces the events in the form of flow chart diagram.
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(2018)Since data-driven business and decision making have ben trending, data has found to be a valuable part of organizations capital. Centralized data warehouse has typically been a solution for organizations to collect, manage and exploit data. While data volumes have gained, also data warehouse technologies have evolved over time and technical architectures have become more complex. In the process of that, metadata has become more essential instrument for managing large-scale data warehouse and analytics environments. Though metadata-based data warehouse architecture and automation have become quite common concepts, there are still potential areas and subsets of metadata left that has been quite out of the spot. One of those is metadata generated by the usage of data warehouse and analytics platform. Capability to measure a product and its usage is one of the key things to improve product technically, but also get insights to the ways that data has been consumed by end users. Before usage metadata and metrics can be analysed and results can be exploited, data must be collected and stored in a format that facilitates its further utilization purposes. That raises questions: how usage-related metadata and metrics should be modelled and stored to facilitate its utilization with other metadata of the data warehouse environment? How that collected usage metadata should be managed? Depending on the technical environment and setup, how usage metadata and metrics can be collected in the first hand? As a result of this study, design process to model database usage by analysing requirements and conceptualizing usage in a hierarchical model is presented. Also logical level reference model for usage metadata and methods for usage metadata management are presented. In addition, concepts for usage metadata and metrics collection process are discussed in the context of Amazon Redshift data warehouse service. Though presented reference model is an example outcome of the design process, phases of the design process can be generalized and exploited when designing usage metadata model in different use cases and technical environments.
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(2012)Henkivakuutuksia käsiteltäessä tarkastelun alla on aina vakuutetun jäljellä oleva elinaika, jota kuvaa positiivinen satunnaismuuttuja T. Usean vakuutetun henkivakuutuksen ollessa kyseessä, oletetaan, että vakuutettujen jäljellä olevat elinajat ovat toisistaan riippumattomia. Toinen henkivakuutusten käsittelyssä olennainen käsite on kuolevuus(intensiteetti), jonka avulla saadaan laskettua todennäköisyyksiä vakuutetun jäljellä olevalle elinajalle. Henkivakuutuslaskennassa vakuutuskaudet voivat olla pitkiä, jopa useita kymmeniä vuosia. Yhtiön kannalta tärkeää on, että vakuutuksen antaminen on kannattavaa. Perusperiaatteena vakuutusyhtiöllä on aina ekvivalenssiperiaate eli vakuutusmaksujen täytyy vastata vakuutetulle maksettavia korvauksia koko vakuutuskauden ajalta. Koska maksuhetkien välillä saattaa olla paljonkin eroa, täytyy vakuutuksien hinnoittelussa ottaa huomioon korkoutuvuus. Usean vakuutetun elämänvaravakuutuksessa korvaus S maksetaan vakuutuskauden lopussa hetkellä n. Korvauksen suuruus riippuu siitä, ketkä vakuutetuista ovat tällöin elossa. Yleensä ensin tiedetään halutun korvauksen suuruus S. Vakuutusmaksun P suuruus saadaan laskemalla hetkeen nolla diskontatun korvauksen S odotusarvo. Usean vakuutetun kuolemanvaravakuutuksessa korvaus maksetaan aina kuoleman sattuessa ennen hetkeä n. Korvaushetkiä voi siis olla yhtä monta kuin on vakuutettujakin. Kuolemanvaravakuutuksen osalta periaate on sama kuin elämänvaravakuutuksessakin, mutta käytännössä laskeminen on paljon haastavampaa, johtuen nimenomaan maksuhetkien lukumäärästä ja ajankohdista. Riskien hallitsemiseksi yhtiölle tärkeä käsite on vastuuvelka, joka on määritelmän mukaan tulevien korvausten ja tulevien vakuutusmaksujen nykyarvojen erotus. Vastuuvelka kertoo siis sen, kuinka paljon yhtiöllä pitää olla varallisuutta, jotta se selviäisi tulevaisuudessa tapahtuvien vakuutustapahtumien seurauksena maksettavista korvauksista. Usean vakuutetun henkivakuutuksia käsiteltäessä vastuuvelan suuruuteen vaikuttaa erityisesti se, missä tilassa prosessi on tarkasteluhetkellä eli ketkä vakuutetuista on elossa ja ketkä kuolleet. Tärkeä apuväline vastuuvelan suuruuden ennustamisessa on Thielen yhtälö, joka kuvaa vastuuvelan muutoksia. Thielen yhtälöä muodostettaessa tarkastellaan virtauskaavion avulla millaisia muutoksia vakuutettujen tiloissa mahdollisesti tapahtuu pienellä aikavälillä. Mahdollisten tapahtumien seurauksena maksettavien korvausten ja maksujen suuruus painotetaan vastaavan tapahtuman todennäköisyydellä, jolloin summasta saadaan muodostettua Thielen differentiaaliyhtälö. Usean vakuutetun henkivakuutuksia on mahdollista lähestyä myös Markov -prosessin näkökulmasta. Tällöin oletetaan, että prosessi siirtyy tilasta toiseen intensiteeteillä, joka vastaa vakuutettujen kuolevuuksia. Nyt prosessin siirtymätodennäköisyydet saadaan laskettua näiden avulla ja vakuutuksen nettokertamaksua laskettaessa sovelletaan samaa periaatetta kuin aikaisemminkin. Markovilainen lähestymistapa helpottaa erityisesti kolmen tai useamman hengen vakuutuksien käsittelyä.
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(2022)The demand for natural and man-made cellulosic-based materials is in an increase continually due to the world population growth. Cotton production does not meet this demand. Consequently, a rational strategy to close this “cellulosic products gap” is to increase the production of man-made cellulosic products, following the principles of green chemistry. Cellulose is an essential skeletal component in plants and is a nearly limitless polymeric raw material with intriguing structure and properties. Due to its inherent insolubility, this crystalline and stiff homopolymer has not yet reached its full application potential. The diversity of regenerated cellulose materials formed through physical dissolution and regeneration has been remarkable in recent decades, showing tremendous possibilities in the fields of textiles, packaging, biomedicine, water treatment, and optical/electrical devices. Since most of the agents used in the physical dissolution and regeneration process can be recycled and reused and the nature of cellulose is preserved, no chemical reactions take place. This method is therefore environmentally friendly and holds the promise of bringing about a new Green Revolution in the widespread use of cellulose-like natural resources. Given the fabrication of new materials using an ecologically benign technology and the replacement of petroleum-based materials, the effects and advantages of such physical processes on society are very fascinating. This thesis includes the dissolution of microcrystalline cellulose (MCC), which represents a highly crystalline and pure cellulose model substrate by 7-methyl-1,5,7- triazabicyclo [4.4.0] dec-5-enium acetate [mTBDH] [OAc] superbase ionic liquid (SIL), which has an extreme dissolution power for cellulose. Cellulose can be first dissolved in IL at 80 ◦C and then regenerated, upon cooling, with the addition of n-propanol as an antisolvent for cellulose, leading to a phase separation. The second part of the thesis is the regeneration of cellulose in the form of films from cellulose-IL solutions. [mTBDH] [OAc] IL was used for the first time as a plasticizer for the preparation of transparent cellulose films.
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(2018)In the case of remote inspection and maintenance operations, the quality and amount of information available to the operator on demand plays a significant role. In knowledge-intensive tasks performed remotely or in a hazardous environment, augmented and virtual reality technologies are often seen as a solution capable of providing the required level of information support. Application of these technologies faced many obstacles over the years, mostly due to the insufficient maturity level of their technical implementations. This thesis contains a description of the research work related to the usage of augmented and virtual reality in remote inspection and maintenance operations, and is aimed at solving some of the most common problems associated with the application of these technologies. During the project, an optical see-through augmented reality glasses calibration method was developed, as well as a virtual reality application for robotic teleoperation. The implemented teleoperation system was tested in two different simulated scenarios, and the additional questions of the immersive environment reconstruction, spatial user interface, connection between virtual and real worlds are addressed in this thesis report.
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(2019)Monitoring of indoor air quality (IAQ) is important because IAQ is directly related to human health and comforts. The purpose of this study was to develop a non-targeted approach for the screening of organic compounds present in indoor air. The sampling was done using cryogenic active and passive samplers, and the separation and analysis were done by using a liquid chromatograph coupled with a triple quadrupole mass spectrometer (LC-QQQ-MS). First, experimental design for sampling by variables, cooling temperature and sampling period was made and optimized to -15 ˚C and 120 minutes respectively to ensure efficient sample collection. For mass spectrometry in both positive and negative ionization modes, the ion source parameters, gas temperature, gas flow, nebulizer pressure and capillary voltage were optimized to 300 ˚C, 10 L/min, 45 psi and 4000 V respectively to enable as much detector response as possible facilitating detection and analysis of the compounds in the sample. The concentration of compounds in the raw sample being very low, one important step was to optimize the sample preparation method to enrich the sample for smooth detection and further analysis. Since the sample was collected in the form of condensate water, different sample preparation methods such as evaporation, liquid-liquid extraction (LLE) and solid-phase extractions (SPEs) with different cartridges were adopted for preconcentration. Comparing the outcomes from different sample preparation methods, it was found that sequential SPE using C2 and C18 cartridges gives maximum compound recovery, e.g., 1.5 and 2.6 times compared to evaporation and LLE respectively in positive ion mode, and 2.6 and 4.1 times in negative ion mode. Therefore, this methodology was adopted to analyze the condensate water samples from two sick houses in Finland. The results from the sick houses were compared with a reference house having no sick building syndrome (SBS) to look for potential compounds causing health issues. The data analysis was done using MZmine 2.3.4 software. Additionally, tandem mass spectrometric (MS/MS) acquisition parameters were optimized and product ions were determined as the initial step of identification of compounds in the sample of the first house. The methods developed in this work would be useful to analyze various natural samples including the analysis of outdoor air also.
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