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(2023)The aim of this thesis is to explore how the Indigenous people’s rights to education in their own language and culture are realized in practice and what are the challenges for providing education that is both high in quality and equal for all. For the context of the research, the rights of Indigenous peoples were studied, and also central to this research were concepts of intercultural bilingual education and Indigenous knowledge. The research data was collected as part of a case study that was carried out during geography field course to the Ecuadorian Amazon in October 2015. The research was carried out using qualitative methods and the research methods were semi-structured interviews and observation. Expert interviews were conducted in Quito, which teachers and parents were interviewed in schools in Ahuano, Santa Clara and Sarayaku. The results are in line with previous research and show that the education does not in all respects consider the cultural and linguistic rights of Indigenous peoples. Even though the majority of the students in the schools selected for the study were Amazonian Kichwa, the language of teaching and instruction was mainly Spanish, and Indigenous language and culture were taught in separate lesson. There were differences between the schools in both resources and curriculums. As a conclusion, it can be stated that teaching is subject to continuous development, but there is no consensus among different actors and communities how it should be organized in the future. On the one hand, there are calls for organizing the teaching independently in accordance with local traditions and cherishing the language and culture of the Indigenous peoples, but the educational policy guidelines and the teaching materials dictate what kind of teaching is available for the children.
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(2021)Indoor localization in Smart factories encounters difficult conditions due to metallic environ- ments. Nevertheless, it is one of the enablers for the ongoing industrial revolution, Industry 4.0. This study investigates the usability of indoor localization in a real factory site by tracking hoist assembly process. To test the hypothesis that indoor localization works in a factory environment, an Ultra- Wideband Indoor Positioning System was installed to cover the hoist assembly space. The system followed hoist assembly trolleys for three weeks after which data was analysed by cal- culating assembly times. The results show that indoor localization with Ultra-Wideband technology is a working solution for industrial environments similar to the tested environment. The time calculations are more accurate than known standard times and reveal that hoist assemblies are not standard and there is wasted time. The results suggest that indoor localization is adaptable to industrial environments and to manufacturing processes. Analysing the processes through the position data provides new knowledge that is used for improving the productivity.
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(2023)Todistaminen matematiikassa nähdään opetuksessa tehtävätyyppinä, jota ei peruskoulussa tai toisen asteen opinnoissa hirveästi harjoitella. Kuitenkin matemaattinen todistaminen on tärkeää, sillä matematiikassa hyödynnetyt kaavat täytyy todistaa, mikäli niitä haluaa käyttää. Tässä tutkielmassa tarkastellaan kolmea pitkän matematiikan ylioppilaskoetehtävää eri kirjoituskerroilta. Tutkielmassa tarkastellaan kokelasratkaisuissa havaittavia virheitä ja virhekäsityksiä pitkän matematiikan ylioppilaskirjoituksien induktiotehtävissä. Tutkielmassa esitellään kokeiden induktiotodistustehtävien vastausmäärät, pistekeskiarvot, pistejakaumat sekä kokelaiden arvosanojen suhteet ansaittuihin pisteisiin. Tutkielman alussa esitetään, miten todistaminen näkyy opetussuunnitelman perusteissa sekä käsitellään induktiotodistus matemaattisesti ja esimerkkien avulla. Neljännessä luvussa esitetään, miten induktiotodistus näkyy lukion oppimateriaaleissa. Luvussa viisi mainitaan aikaisempia tutkimuksia induktiotodistuksesta toisen asteen oppilaitoksissa sekä yliopistoissa. Pitkän matematiikan ylioppilaskoe esitellään luvussa kuusi. Luvussa seitsemän kerrotaan, miten tutkimus on toteutettu. Lisäksi luvussa esitetään tarkasteltavana olevat ylioppilaskoetehtävät, niiden ratkaisut sekä kokelasratkaisujen analysointi. Kahdeksannessa luvussa vertaillaan tutkimuksen tuloksia aikaisempiin tutkimuksiin. Luvuissa yhdeksän ja kymmenen pohditaan tutkimuksen luotettavuutta sekä mahdollisia jatkotutkimuskohteita. Tutkimuksessa käsiteltyjen kokelasratkaisujen perusteella voidaan todeta, että mitä paremman arvosanan kokeesta sai, sen parempia pistemääriä induktiotodistustehtävistä oli saatu. Induktiotodistustehtäviä kokelaat olivat tehneet vähän ja pistemäärät tehtävissä olivat alhaiset. Analyysin perusteella suurin virhekäsitys koskee induktiovaihetta. Kokelaat eivät osanneet muodostaa induktio-oletusta ja käyttää sitä hyödyksi induktioväitteen todistamiseen. Kokelailla oli haasteita peruslaskutoimituksissa sekä summan määritelmässä. Opetuksellisesta näkökulmasta tutkimuksen tulokset ovat merkittäviä, sillä oppilaiden on sisäistettävä matemaattiset ilmiöt ja sovellettava niitä sekä käytännössä että ohjelmistoja käyttäessä. Tutkimuksen tulokset tukevat aikaisemmin tehtyjen tutkimuksien tuloksia. Tulevaisuudessa voisi tutkia, tukeeko tutkimukseni kevään 2023 ylioppilaskokeen induktiotehtävissä ilmeneviä virhekäsityksiä, sekä mitä virhekäsityksiä yliopisto-opiskelijoilla on induktiotodistusta käsittelevän kurssin aikana tai kurssin jälkeen.
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(2012)Magnetic properties of Kevitsa intrusion are studied in this thesis. The goal is to find a reason for a negative magnetic anomaly observed in the center of dunite layer of the Kevitsa intrusion. This thesis concentrates mainly on petrophysical measurements made from drill hole samples, but also previous geophysical measurements from the study area are used. The first approximation is that the negative magnetic anomaly is caused by a strong remanent magnetization which has a direction that opposes geomagnetic field and induced magnetization. This kind of remanent magnetization is most likely formed during a reversed polarity period of geomagnetic field. An approximately 55 meters thick layer of strong remanent magnetization can be observed in drill hole KV297, which is located on the negative surface-magnetic anomaly. The average Königsberger ratio in the samples from this layer is 4.2 and the average inclination of remanent magnetization is -42.4 degrees. Declination of remanent magnetization stays unknown, because none of the samples were directional. One can also observe two distinct magnetic layers in the dunite layer of drill hole KV297. The lower one of these magnetic layers extends to approximately 160 meters. Both of these layers are strongly magnetized, but only the upper one has a strong remanent magnetization. In drill hole KV200 one cannot observe a strong remanent magnetization, but this drill hole is not located on the negative surface-magnetic anomaly either. However, the samples from the drill hole KV200 have a strong magnetic susceptibility. Based on these observations one can conclude that the dunite layer of the Kevitsa intrusion is overall strongly magnetic, but only the center part of it has a strong remanent magnetization. This layer of strong remanent magnetization is the cause of negative magnetic anomaly observed on the surface. The direct mathematical models, which are based on the measured petrophysical data, are consistent with the magnetic anomaly observed on the surface. In the models the declination of remanent magnetization is set to 240 degrees.
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(2022)A US government agency estimated the national cost of inadequate software testing to be \$60 billion annually, and that was 20 years ago. As the role of technology and software has been rapidly increasing worldwide for decades, it suffices to say that the worldwide fiscal effect of poor testing practices today is probably ``quite a bit``. An increasing number of industry-focused survey studies on testing have been published worldwide in recent years, signalling an increased need to characterize the testing practices of the software development industry. These types of studies can help to guide future research efforts towards subjects that are meaningful to the industry, and provide practitioners with an opportunity to compare their own practice to those of their peers and recognize the main improvement areas. As no secondary study devoted to these types of survey studies could be identified, the opportunity was seized to carry out a literature review was to find out what the data from these studies can tell us when aggregated. The precise topics focused on were the usage of test levels, test types, test design techniques, test tools and test automation. Looking at these studies in aggregate tells us about some general trends: unit testing, functional testing and regression testing are popular everywhere, and also quite popular regardless of the surveyed population are performance testing and usability testing. The popularity of the other test levels and test types vary from survey to survey or region to region. Black-box techniques and experience-based techniques are more popular than white-box techniques. Exploratory testing, error guessing, use case testing and boundary value analysis are some of the most popular test design techniques. Much of the industry relies on manual testing over automated testing and/or have inadequately adopted the usage of testing tools.
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(2023)Microbial growth dynamics play an important role in virtually any ecosystem. To know the underlying laws of growth would help in understanding how bacteria interact with each other and their environment. In this thesis we try to automate the process of scientific discovery of said dynamics, via symbolic regression. It has historically been implemented with genetic algorithms, and although many of the new implementations have different approaches, we stick with a highly optimized genetic-programming based package. Whatever the approach, the purpose of symbolic regression is to search for a mathematical expression that explains a response variable. We test the highly interpretable machine learning method on several datasets, each generated to mimic certain patterns of growth. Our findings confirm its ability to reverse-engineer theory from data. Even when the generating equations contain the latent nutrient variable, whose dynamics are not observable through the raw data, symbolic regression is able to find an analytically correct reparametrization and exact solution. In this thesis we discuss these results and give an overview of symbolic regression and its applications.
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(2022)The 1.64 Ga Ahvenisto complex in the southeastern Finland, is an anorthosite-mangerite-charnokite-granite (AMCG) suite, which has been discovered to host conspicuous magma interaction structures formed in magma mixing and mingling. These structures form areas where the consequences of mingling are found as monzodioritic pillows and granitic veins forming net-veined complexes. Mixing of monzodioritic and hornblende granitic magmas has produced hybrid rocks with intermediate composition. The main goals of the study were to report the major element mineral chemistry of the main minerals (plagioclase, alkali-feldspar, amphibole, and pyroxene) from the hybrid rocks, hornblende granite, and monzodiorite and to test the suitability of geothermobarometric methods for the rock types related to the different magma interaction structures and to evaluate crystallization pressures and temperatures of the pertinent magmas. The magma interaction structures of the Ahvenisto complex are recognized in the mineral chemistry of the mingling and mixing related rocks. The mineral chemistry confirms that the hornblende-granite represents the most primitive granitic phase in the mixing set and the composition of the minerals change as the mixing proceeds towards the final hybrid rock. The mineral chemistry from the monzodiorites reveals that the monzodiorites from different areas of the Ahvenisto complex have distinguished features and they can be separated by their composition. Hornblende-plagioclase thermobarometers and two-pyroxene thermometers were used, and the results were compared to the previous studies related to the emplacement conditions of the Ahvenisto complex. The hornblende-plagioclase thermobarometers suggest that the crystallization of the mixing related rocks took place at ~790–860°C. For the temperature results, pressures of 100 MPa and 300 MPa were used based on earlier studies and a conclusion is drawn that the pressure has had only minor impact on the temperature. The two-pyroxene thermometers show similar regional difference for the crystallization temperatures of the monzodioritic rocks as recognized in the mineral chemistry. The results from the two-pyroxene thermometers show wider variation in the temperatures, which leaves some uncertainty on the liability of the results. The variation is mainly explained by the mineral chemistry of the mafic silicate minerals in the Ahvenisto complex rocks being very iron-rich and outside the calibration standards of the geothermobarometers.
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(2015)Tutkielmassa esitetään kuvailevan vaativuusteorian tulos inflatorisen kiintopistelogiikan ja polynomisen ajan vaativuusluokan yhteydestä. Tuloksen todistamiseen tarvittavat logiikan ja vaativuusteorian pohjatiedot käydään tutkielmassa läpi. Joukko-opin perusteet ja yleiset merkinnät toivotaan lukijalle entuudesta tutuiksi. Inflatorinen kiintopistelogiikka on ensimmäisen kertaluvun logiikan laajennus, johon on lisätty inflatoriseksi kiintopistekvantifioinniksi kutsuttu kaavanmuodostussääntö. Inflatorinen kiintopistekvantifiointi määrittelee relaation induktiivisesti ja sopii hyvin kuvailemaan tietokoneiden iteratiivisia ja rekursiivisia toimenpiteitä. Rajoittumalla äärellisiin järjestettyihin malleihin saadaan inflatorisen kiintopistelogiikan ilmaisuvoima vastaamaan vaativuusteorian polynomisen ajan vaativuusluokkaa. Vaativuusteoriassa käytetään Turingin koneita työkaluna ongelmien ratkaisemiseen tarvittavia resursseja arvioitaessa. Resurssivaativuuksiltaan samankaltaisia ongelmia luokitellaan vaativuusluokkiin. Polynomisen ajan vaativuusluokka on luokka kaikille ongelmille, jotka voidaan ratkaista syötteen pituudesta polynomisesti riippuvassa määrässä Turingin koneen laskennan askelia. Inflatorisen kiintopistelogiikan ja polynomisen ajan vaativuusluokan yhteyden osoittamiseksi tutkielmassa esitetään, kuinka kuvailla logiikan malleja Turingin koneilla ja Turingin koneita logiikan kaavoilla. Tarvittavien työkalujen esittelyjä seuraa tutkielman päätulos: inflatorinen kiintopistelogiikka karakterisoi polynomisen ajan vaativuusluokan. Lopuksi käydään läpi järjestyksen olettamisen tarpeellisuutta.
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(2015)Maximizing influence in graphs, typically applied to Social Networks, is the problem of finding a set of nodes with the highest overall influence on the entire graph. In marketing domain for example, it is used to find the set of people who have the highest influence on their local communities. As a result, instead of blindly marketing a product to a large group of people, the product is marketed to this group of selected users, and they will in turn help spreading the word. The problem has been studied extensively, and several state of the art methods have been proposed. But all of these methods have one common flaw, none of them are scalable. Even on small graphs, current methods take extremely long amount of time and introduction of bigger data sets have rendered some of these methods completely useless. Over the past two decades, collection of data has become easier and a very common practice. This is mostly credited to the advancements in hardware and software technologies as well as the introduction of World Wide Web. To overcome issues related to big data sets, large scale data processing platforms have been developed to tackle scalability issues of problems similar to the influence maximization. Most notably are the two frameworks called Hadoop and Spark that contain many features for simple data processing, machine learning and graph processing. In this thesis work, some of the current influence maximization algorithms are implemented in these two frameworks, some new methods are proposed, experiments on graphs of different sizes are performed and the results are reported.
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(2021)Vulkaanisten kaarten magmaattinen aktiivisuus nostaa maankuoren lämpötilaa ja laskee sen kestävyyttä, mutta näiden muutosten suuruutta tai muutosten erinäisiä tekijöitä, kuten latenttilämpöä, sulamisesta aiheutunutta viskositeetin laskua sekä intruusioiden koostumusta, lämpötilaa ja sulan määrää ei ole laajemmilta osin tutkittu. Pro gradu tutkielman tarkoitus on kvantifioida näitä kuoressa tapahtuvia muutoksia sekä tutkia erinäisten tekijöiden vaikutusta kallioperän kestävyyteen, kuten sitä kuinka kestävyys muuttuu lämpötilan nousun seurauksena kiinteässä tilassa verrattuna siihen miten se muuttuu kiven sulaessa. Näitä näkökulmia tutkitaan mallilla, joka perustuu kaksiulotteiseen lämpöyhtälöön, joka ratkaistaan differenssimenetelmällä. Kuoren kestävyyden muutoksia lasketaan sarjalla yksiulotteisia kuoren kestävyyskriteerimalleja. Kivien sulamislämpötilat saadaan termodynaamisella ohjelmalla, joka laskee sulafraktiot eri paine ja lämpötilaolosuhteissa ja näitä sulia käytetään hyväksi mallissa, joka laskee efektiivisen viskositeetin osittain sulaneelle kivelle. Kuoren kestävyyttä ja lämpötilan muutoksia tarkastellaan tekemällä useampia simulaatioita, jotka jäljittelevät magmaattisen kaaren vulkanismia. Maankuoren integroitu kestävyys laskee magmakammioiden läheisyydessä jo muutaman miljoonan vuoden kuluttua ~80 % eikä tämä arvo muutu huomattavasti jatkuvan magmaattisen aktiivisuuden seurauksena. Magmakammioita ympäröivä maankuori kuitenkin jatkaa heikentymistä koko magmaattisen aktiivisuuden ajan (10 Ma) eikä tämä ei ole ainoastaan seurausta hitaasta lämmönjohtumisesta. Magmaattisen aktiivisuuden päätyttyä maankuori jäähtyy ja kiteytyy, jolloin intruusioiden mekaaniset ominaisuudet saattavat joko heikentää tai kestävöittää kallioperää suhteessa maankuoren alkuperäiseen kestävyyteen riippuen intruusioiden ja niitä ympäröivän kiven mekaanisista ominaisuuksista. Mafiset intruusion kykenevät kestävöittämään kallioperää helpommin syvemmällä, missä kuori alun perin deformoitui plastisesti, kun taas felsiset intruusiot kykenevät mekaanisesti heikentämään maankuorta matalammilla syvyyksillä. Pitkällä aikavälillä intrudoituvan magman lämpötila on vähemmän tärkeä tekijä kuoren kestävyydelle, kuin intruusioiden mekaaniset ominaisuudet. Kiven sulamisella ei näytä olevan huomattavaa vaikutusta kuoren kestävyyden muutoksiin. Suurin osa simulaatioista osoittaa, että kuoren integroitu kestävyys on pudonnut jo yli 99.9 % lämpötilan nousun seurauksena ennen kuin kuori alkaa sulamaan. Jopa äärimmäisimmissä skenaarioissa kuoren sulamisesta aiheutuva integroidun kestävyyden lasku pysyy pääsääntöisesti 0.5 % alapuolella. Mitä enemmän magmassa on sulaa, sitä suurempi vaikutus latenttilämmöllä on kuoren lämpötiloihin. Magmaattisen aktiivisuude aikana intrudoituvalla magmalla minkä sulamäärä on 10–100 %, latenttilämmön osuus lämpötilan noususta on 12–34 %. Latenttilämpö vaikuttaa enemmän kuoren kestävyyteen magmakammioiden läheisyydessä ja laskee kuoren kestävyyttä enemmän magmaattisen aktiivisuuden päätyttyä. Maximissaan latenttilämmöstä aiheutunut kuoren integroidun kestävyyden lasku on 10–30 % magmakammioiden läheisyydessä ja keskiarvo on 5–17.5 % 50 km säteellä magmakammioista, riippuen magman alkuperäisestä sulan määrästä. Tektoniikan kannalta on tärkeää ymmärtää miten magmaattinen aktiivisuus vaikuttaa maankuoren kestävyyteen. Maankuori on heikoimmillaan suoraan magmakammioiden läheisyydessä magmaattisen aktiivisuuden aikana, joka saattaa aiheuttaa paikallisia muutoksia kuoren deformaatiossa ja hiertovyöhykkeiden muodostumisessa, mutta pitkällä aikavälillä intruusioiden koostumus ja niiden mekaaniset ominaisuudet saattavat vaikuttaa huomattavasti kuoren kestävyyteen. Koska kuoren sulamisesta aiheutunut viskositeetin lasku ei ole huomattava tekijä kuoren kestävyydelle, niin muut magmaattiseen aktiivisuuteen ja vulkanismiin liittyvät tekijät ovat todennäköisesti tärkeämmässä osassa, kuten kiven sulamiseen liittyvä tiheyden lasku ja tilavuuden kasvu, joka taas johtaa uusiin maankuoreen syntyviin jännityskenttiin, kallioperän murrosten syntymiseen sekä magman liikkumiseen.
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(2022)The Baltic Sea is undergoing changes due to climate change, including an increase in its temperature. This may in turn lead to changes in the traits of the species that inhabit it, including non-endemic, invasive species. Palaemon elegans is a species native to the Atlantic Ocean that has been present in the Baltic Sea since the beginning of this century. Abilities such as high thermal tolerance make it successful in colonising new ecosystems like the brackish waters of this sea. However, less is known about the behavioural traits’ adaptions to these changes. This study aims then to find out how climate change may affect the behaviour of this species. To do so, five behaviours expressed by this species were observed and analysed to see how temperature change, seabed composition and body size influence their expression. The behaviours analysed were aggressiveness, movement frequency, reaction to food stimulus, number of feeding interactions and shelter-seeking. Analyses were conducted using ten-minute videos with ten specimens of P. elegans placed in water tanks and interacting in ecosystems representations with elements typical of the seabed where this species lives, both vegetation and rocks. Student's t-tests in R were then performed to test the significance of possible differences between the behaviours studied and the three parameters that may influence their expression. The results obtained show that the increase in water temperature might indeed lead to an increase in the frequency of the five behaviours studied except in aggressiveness. On the other hand, it was found that the composition of the ecosystem does not have a significant influence overall, while body size has a major influence on feeding related behaviours. Therefore,knowing more about changes in the behavior of species susceptible to climate change can be helpful to understand how biodiversity and its distribution will vary in the not so distant and changing future and what consequences it may generate at the ecosystem level.
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(2024)Aerosol particles are a significant factor both environmentally and in terms of health. They can influence climate change in various ways: certain aerosol particles contribute to warming the atmosphere, while others may have a cooling effect. The concentration of secondary organic aerosol (SOA) in the atmosphere is significant, thus playing a crucial role in the climate. SOA can influence the temperature of the climate and the chemistry of the atmosphere. SOA are formed through the oxidation of volatile organic compounds (VOCs), creating a complex mixture of various less volatile organic compounds with diverse properties. Highly oxygenated organic molecules, products of VOC oxidation, are estimated to explain a substantial part of SOA formation. To assess the climate impacts accurately, it is essential to comprehend the characteristics of SOA in the atmosphere. The aim of the thesis was to investigate the influence of temperature and prefence of dimethyl sulfide (DMS) on the gas-phase oxidation products of VOCs, especially how temperature affects the formation of accretion products. The compounds and ozone reacted in a flow tube, and the resulting oxidation products were ionized by clustering them with reagent ions. The mass-to-charge ratio of the formed charged clusters was then measured with orbitrap mass spectrometer. Identifiable oxidation products were selected based on studies by Rissanen et al. [2014] and Tomaz et al. [2021], and the previously described products in these studies were followed using the Orbitool program. The starting materials used in this thesis were cyclohexene, deuterated cyclohexene, and limonene, which were oxidized in the presence of ozone. Several oxidation products were observed in the measurements that were expected to form based on literature. However, mass spectra also revealed that the reaction time with deuterated cyclohexene might have been too short. With a longer reaction time, the molecules could have undergone further oxidation, allowing better detection of oxidation products. In the thesis, it was observed that temperature influences the formation of oxidized products; as the temperature increases, oxidation reactions progress further in 2.7 s reaction time. Monomers that underwent more extensive oxidation could form more highly oxidized accretion products. DMS likely reacts with hydroxyl radicals, thereby influencing the oxidation of VOC compounds in the flow tube. Measurements conducted with DMS may result in the formation of more organic alkoxy radicals than organic peroxy radicals, which could undergo further oxidation.
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(2013)Tropical Africa has been under intense land cover change during the last decades. Human activities have had an impact on natural ecosystems and this has accelerated changes in them. Soil can be considered as an ecosystem and changes in natural soil formation can lead to soil loss and erosion. Taita Hills located in south-east Kenya are no exception. Almost all recoverable land is used for agriculture in these subtropical hills despite the great altitude differences and steepness of the hill slopes. Wundanyi catchment at the altitude 1400 - 2100m above sea level was studied in order to identify certain physical parameters of the soil in the hills and to define if these could be explained by changes in the physical environment like alteration in altitude, slope angle and land uses. A total of 68 study points were selected within the catchment in order to represent different physical environments. At each study point, the slope angle was measured, an approximately one meter deep soil cut was dug into the hill slope of which the soil profile was drawn and the subsamples were taken for the grain size analysis and bulk density determination. At 21 study points, the soil was not sampled due to a thick humus layer. The soil hydraulic conductivity was determined experimentally at three study points with an infiltration ring and theoretically for the rest of the study points by estimation, using other physical soil properties obtained from grain size analysis. The soil at the Wundanyi catchment was found to be massive, chemically weathered fine residual soil originating from the weathered gneissic bedrock. It was discovered that generally the soil is quite homogeneous within the catchment area and the physical parameters of the soil are similar despite the different land cover classes. The most common soil type at the catchment is fine sand. The deepness of the organic layer varied greatly, the mean being 0.7 meters. The thickest organic layers were found in indigenous forests and in places that had not been used for agricultural purposes. Soil hydraulic conductivity at the studied area is low. The degree of correlation between soil grain size distribution and varying physical environments was found low. However, there seems to be moderate correlation between the elevation and the proportion of clay and the aspect and the proportion of clay. Topographic environment mainly defines the land use and land cover within the studied area. Only the steepest slopes and areas that are not accessible have avoided the excessive exploitation of the soil. The vegetation protects the mineral soil and, therefore, the removal of natural vegetation exposes the soil to impacts of climatic conditions. The exposition of the soil together with fine soil texture can reduce the infiltration making the soil compacted. This increases the surface runoff, which can increase the sediment transportation and can lead to environmental problems such as erosion, gullying, silting of rivers and transportation of nutrients to rivers. Signs of these environmental problems can already be seen at the Taita Hills, proving that soil exploitation is not sustainable.
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(2013)Tutkielmassa käsitellään informaatioteoriaa hevosraveissa ja osakemarkkinoilla. Hevosravien tapauksessa tutkitaan optimaalista vedonlyöntistrategiaa ja yritetään löytää paras tapa kasvattaa uhkapelaajan varallisuutta pitäen riskit mahdollisimman pieninä. Tällöin puhutaan tuplaantumisnopeudesta ja sen maksimoinnista. Tämän yhteydessä todetaan, että optimaalista on hajauttaa panokset samassa suhteessa, kuin mikä on hevosten voittotodennäköisyys. Vedonlyöjä tekee voittoa silloin, kun hänen estimaattinsa hevosten voittotodennäköisyyksille ovat paremmat kuin vedonvälittäjän tekemät estimaatit. Lisäksi tutkitaan, kuinka paljon vedonlyöjän varallisuus kasvaa, jos hänellä on tietoa aiempien kilpailujen tuloksista, eli sivuinformaatiota. Havaitaan, että tuplaantumisnopeuden kasvu on sama kuin ravien ja sivuinformaation yhteisinformaatio. Lopuksi osoitetaan, että entropian ja tuplaantumisnopeuden summa on vakio. Osakemarkkinoiden tapauksessa keskitytään sijoittajan varallisuuden kasvun ja markkinoiden entropian tason väliseen yhteyteen. Kuten ravien tapauksessa, käsitellään tässäkin tuplaantumisnopeutta ja sen maksimointia. Tällöin pyritään löytämään sekä kilpailun että kasvun suhteen optimaalinen osakesalkku. Havaitaan, että maksimoimalla asymptoottista kasvua maksimoituu myös sijoittajan suhteellinen varallisuus. Osakemarkkinoidenkin tapauksessa käsitellään sivuinformaation vaikutusta tuplaantumisnopeuteen, sekä investointistrategioita, jotka ovat riippuvaisia markkinoiden menneistä arvoista. Lopuksi löydetään asymptoottinen tuplaantumisnopeus ergodisille osakemarkkinaprosesseille.
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(2020)Tässä tutkielmassa analysoidaan yritysten välisiä informaatiovirtoja yritysverkostoissa, jonka viitekehyksenä on palveluekosysteemi. Tutkielmassa käsitellään informaation eheyden tarpeellisuutta ja merkitystä sekä menetelmiä, joilla informaation eheydestä voi varmistua. Tutkielmassa seurataan informaatiovirran kulkemista yrityksestä toiseen. Lisäksi käsitellään yritysten informaation tarvetta, yritysten yhteentoimivuutta, sekä menetelmiä, joita palveluekosysteemi ja ontologiat tarjoavat informaation kontrolloinnille ja hallinnoinnille.
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(2019)In model selection, it is necessary to select a model from a set of candidate models based on some observed data. The model should fit the data well, but without being overly complex, since that would not allow the model to generalize well its predictions to unseen data. Information criteria are widely used model selection methods that select a model based on some criteria. Information criteria estimate a score for each candidate model, and use that score to make a selection. A common way of estimating such a score, rewards the candidate model for its goodness of fit on some observed data and penalizes for the model complexity. Many popular information criteria, such as Akaike's Information Criterion (AIC) and Bayesian Information Criterion (BIC) penalize model complexity by the feature dimension. However, in a non-standard setting with inherent dependencies, these criteria are prone to over-penalizing the complexity of the model. Motivated by how these commonly used criteria tend to over-penalize, we evaluate AIC and BIC on a multi-target setting with correlated features. We compare AIC and BIC, with the Fisher Information Criterion (FIC), a criterion that takes into consideration correlations amongst features and does not penalize model complexity solely by the feature dimension of the candidate model. We evaluate the feature selection and predictive performances of the three information criteria in a linear regression setting with correlated features. We evaluate the precision, recall and F1 score of the set of features each criterion selects, compared to the feature set of the generative model. Under this setting's assumptions, we find that FIC yields the best results, compared to AIC and BIC, both in the feature selection and predictive performance evaluation. Finally, using FIC's properties for feature selection, we derive a formulation that allows to approximate the effective feature dimension of models with correlated features, in linear regression settings.
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(2019)In this work, five text vectorisation models' capability in embedding Finnish case law texts to vector space for inter-textual similarity computation is studied. The embeddings and their computed similarities are used to create a Finnish case law retrieval system that allows effective querying with full documents. A working web application is presented as a part of the work. The case law data for the work is provided by the Finnish Ministry of Justice, and the studied models are: TF-IDF, LDA, Word2Vec, Doc2Vec and Doc2vecC.
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(2014)The purpose of this thesis is to elaborate how to implement Search-assisted Search (SAS) scheme on the ONE simulator and analyze whether it has better performance compared with other protocols (such as, Spray and Wait Routing Protocol). SAS is a search scheme that is designed for Delay- tolerant networks (DTN). The main characteristic of DTN is intermittent connectivity. There are two popular routing protocols, called Epidemic Routing Protocol and Spray and Wait Routing Protocol. Epidemic Routing Protocol is the one that floods an unlimited number of messages towards the desired destination. On the other hand, Spray and Wait Routing Protocol sprays a limited number of messages and delivers them to several nodes. When those nodes with a copy of the message encounter the desired destination, they will inform the one which initializes the search that the destination has been found. To improve search performance, SAS has several new properties: improvement of the number of contents' carriers and community. SAS contains the benefit of Spray and Wait scheme, which sprays a limited number of messages to the encountered nodes. This method accelerates the searching node to locate the content. However, only depending on spraying a number of messages is not enough. SAS increases the number of nodes carrying contents. Theoretically, this design improves the probability of locating the desired content. For making implementation of SAS on the ONE simulator easier, I involve a concept of geo-community. Geo-community represents the nodes having the similar interest are gathered together within geographical community.
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Information theoretical analysis of ULF Pc5 waves and electron fluxes at the Earth's radiation belts (2024)In this study we use mutual information to characterise statistical dependencies of seed and rel- ativistic electron fluxes in the Earth’s radiation belts on ultra-low frequency (ULF) wave power measured on the ground and at geostationary orbit. The benefit of mutual information, in com- parison to measures such as the Pearson correlation, lies in its capacity to distinguish non-linear dependencies from linear ones. We replicate the methodology in Simms et al. [2014] andwe also calculatethe conditional mutual information, CMI, between ULF spectral power and the electron fluxes, when conditioned on the solar wind speed V . The results of the replication are similar to those presented in Simms et al. [2014] and show low to moderate correlations between ULF Pc5 waves (2-7 mHz electromagnetic waves) and both relativistic and seed electron fluxes, with the correlations ranging from 0.18 to 0.65. The mutual information between ULF Pc5 spectral power and the relativistic electron flux is between 0.17 and 0.22 depending on whether it is evaluated for a storm’s main or recovery phase. The corresponding values of mutual information between ULF Pc5 spectral power and the seed electron flux are between 0.33 and 0.41. All the values of mutual information are statistically significant with a confidence interval of at least 8 standard deviations, except for the mutual information between ground-based ULF measurements and the relativistic electron flux. Highest values of CMI are obtained for roughly V > 600km/s, which also give the largest significance ratios for CMI, implying that under conditions with high solar wind speeds the dependence between ULF Pc5 spectral power and the electron fluxes at the outer radiation belts is higher than for lower solar wind speeds. The mutual information and CMI between the ULF spectral power and the seed electron fluxes is larger and up to twice as high as between ULF spectral power and the relativistic electron flux. The mutual information between average ULF spectral power and the peak electron flux after a storm is also higher than the regular mutual information, giving indication of a dependence whose timing might vary on a scale of days.
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(Helsingin yliopistoHelsingfors universitetUniversity of Helsinki, 2008)Information visualization is a process of constructing a visual presentation of abstract quantitative data. The characteristics of visual perception enable humans to recognize patterns, trends and anomalies inherent in the data with little effort in a visual display. Such properties of the data are likely to be missed in a purely text-based presentation. Visualizations are therefore widely used in contemporary business decision support systems. Visual user interfaces called dashboards are tools for reporting the status of a company and its business environment to facilitate business intelligence (BI) and performance management activities. In this study, we examine the research on the principles of human visual perception and information visualization as well as the application of visualization in a business decision support system. A review of current BI software products reveals that the visualizations included in them are often quite ineffective in communicating important information. Based on the principles of visual perception and information visualization, we summarize a set of design guidelines for creating effective visual reporting interfaces.
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