Havaintojärjestelmäkokeet numeerisessa sään ennustamisessa

Sään ennustamisessa tärkeä työväline on numeerinen säämalli, jossa ilmakehän tilan kuvaaminen perustuu niin sanottujen perusyhtälöiden ratkaisemiseen. Niiden avulla lasketaan tuulen nopeuden, ilmanpaineen, lämpötilan ja kosteuden muutokset pienin aika-askelin eteenpäin. Numeerinen säämalli tarvitsee lähtötiedokseen laadultaan hyviä havaintoja ilmakehän todellisesta tilasta. Joka vuorokausi kymmenet in-situ- ja kaukohavaintojärjestelmät tekevät havaintoja ilmakehästä sen pintakerroksesta ylärajaan asti. Pelkät havainnot eivät kuitenkaan riitä antamaan tarpeeksi tarkkoja lähtötietoja säämallille. Ongelman ratkaisu on data-assimilaatiojärjestelmä. Se yhdistää laatukontrollin läpikäyneen havaintotiedon ja mallitiedon, jota kutsutaan ennakkokentäksi, ja luo niiden avulla analyysin ilmakehän todellisesta tilasta. Havaintojärjestelmäkokeiden (OSE) avulla testataan havaintojärjestelmien vaikutuksia data-assimilaatiojärjestelmän tuottamien analyysien ja niistä tuotettujen sääennusteiden laatuun. OSE:n avulla selvitetään, kuinka hyvin saatavilla olevia havaintoja käytetään hyväksi, tai kannattaako jokin uusi havaintojärjestelmä ottaa mukaan operatiiviseen ennustusjärjestelmään. Tämän tutkielman aluksi tutustutaan lyhyesti numeerisiin säämalleihin, havaintojärjestelmiin ja dataassimilaatiojärjestelmiin, minkä jälkeen tehdään yleinen kirjallisuuskatsaus havaintojärjestelmäkokeiden suorittamisesta. Sen jälkeen keskitytään Doppler-säätutkan tuottamien tutkasäteen suuntaisten tuulen nopeushavaintojen hyödyntämiseen rajoitetun alueen HIRLAM-säämallissa, mitä on tutkittu viime vuosina Ilmatieteen laitoksessa (IL). Kaukohavaintojärjestelmien käyttö on lisääntynyt viime vuosien aikana kehittyneiden analyysimenetelmien ansiosta. Tavanomaisten in-situ- havaintojärjestelmien raju vähentäminen dataassimilaatiossa ei näytä kuitenkaan vielä olevan mahdollista. Kaukohavainnot ovat useiden OSE-kokeiden perusteella parantaneet analyysiä ja ennusteita erityisesti alueilla, joissa tavanomainen havaintoverkosto on harva. Tutkatuulihavaintojen on ajateltu tuovan parannuksia rajoitetun alueen säämalleihin, sillä niiden avulla saadaan tärkeää lisätietoa tuulen ageostrofisista ominaisuuksista. Sen johdosta pienen mittakaavan sääilmiöiden kuten meri- ja rinnetuulien ennustettavuuden toivotaan paranevan. IL:ssa on kehitetty tutkatuulihavaintojen käsittely- ja mallintamismenetelmiä, minkä jälkeen on suoritettu OSE Suomen tutkaverkoston tuulihavainnoilla aikavälille 1.-29.2.2008 HIRLAMin operatiiviselle 3D-VAR dataassimilaatiojärjestelmälle. Kyseisen OSE:n aineisto on saatu käyttöön tähän tutkielmaan. Kontrolliassimilaatiossa CON ovat mukana kaikki operatiiviset havaintojärjestelmät ja koeassimilaatioon RAD_ALL on syötetty myös tutkatuulihavainnot. Tässä tutkielmassa OSE:n tulokset todennetaan TEMP-tuulihavaintojen avulla tutkimalla ennakkokentän ja analyysin harhaa sekä satunnaisvirhettä. Tulosten perusteella tutkatuulihavainnot parantavat ennakkokenttää ja analyysiä erityisesti keskitroposfäärissä, mutta alatroposfäärissä vaikutus analyysiin on lähes neutraali. Koska tutkatuulihavainnot ulottuvat n. 4-6 km korkeuteen, ne eivät vaikuta ylätroposfäärin analyysiin. Tulokset eivät kuitenkaan ole tilastollisen testin perusteella tilastollisesti merkitseviä. Parhaimmillaan RAD_ALLassimilaation voidaan osoittaa olevan CON-assimilaatiota parempi 20% merkitsevyystasolla. Lopuksi suoritettu tapaustutkimus osoittaa, että tutkatuulihavaintojen vaikutus näkyy tuulen nopeuden analyysi-inkrementtikentässä sekä jossain määrin myös lyhyessä 12h pintapaine-ennusteessa Suomen alueella. Tapaustutkimuksen perusteella tutkatuulihavaintojen vaikutus analyysiin ja ennusteeseen näyttäisi olevan lähes neutraali. OSE:n toistaminen kesäkuukaudelle voisi olla hyödyllistä, koska talvella ei esiinny esimerkiksi merituulia. Tämän tutkielman tulosten perusteella tutkatuulihavaintojen käyttäminen HIRLAMin 3D-VAR assimilaatiojärjestelmässä on hyödyllistä. Avainsanat – Nyckelord – Keywords Havaintojärjestelmäkoe, data-assimilaatio, Doppler-tutkatuulihavainto Säilytyspaikka – Förvaringställe – Where deposited Kumpulan tiedekirjasto

Miniaturized mass spectrometric ionization techniques for environmental analysis and bioanalysis

Miniaturized mass spectrometric ionization techniques for environmental analysis and bioanalysis Novel miniaturized mass spectrometric ionization techniques based on atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) were studied and evaluated in the analysis of environmental samples and biosamples. The three analytical systems investigated here were gas chromatography-microchip atmospheric pressure chemical ionization-mass spectrometry (GC-µAPCI-MS) and gas chromatography-microchip atmospheric pressure photoionization-mass spectrometry (GC-µAPPI-MS), where sample pretreatment and chromatographic separation precede ionization, and desorption atmospheric pressure photoionization-mass spectrometry (DAPPI-MS), where the samples are analyzed either as such or after minimal pretreatment. The gas chromatography-microchip atmospheric pressure ionization-mass spectrometry (GC-µAPI-MS) instrumentations were used in the analysis of polychlorinated biphenyls (PCBs) in negative ion mode and 2-quinolinone-derived selective androgen receptor modulators (SARMs) in positive ion mode. The analytical characteristics (i.e., limits of detection, linear ranges, and repeatabilities) of the methods were evaluated with PCB standards and SARMs in urine. All methods showed good analytical characteristics and potential for quantitative environmental analysis or bioanalysis. Desorption and ionization mechanisms in DAPPI were studied. Desorption was found to be a thermal process, with the efficiency strongly depending on thermal conductivity of the sampling surface. Probably the size and polarity of the analyte also play a role. In positive ion mode, the ionization is dependent on the ionization energy and proton affinity of the analyte and the spray solvent, while in negative ion mode the ionization mechanism is determined by the electron affinity and gas-phase acidity of the analyte and the spray solvent. DAPPI-MS was tested in the fast screening analysis of environmental, food, and forensic samples, and the results demonstrated the feasibility of DAPPI-MS for rapid screening analysis of authentic samples.

Radical Enhanced Atomic Layer Deposition of Metals and Oxides

Atomic Layer Deposition (ALD) is a chemical, gas-phase thin film deposition method. It is known for its ability for accurate and precise thickness control, and uniform and conformal film growth. One area where ALD has not yet excelled is film deposition at low temperatures. Also deposition of metals, besides the noble metals, has proven to be quite challenging. To alleviate these limitations, more aggressive reactants are required. One such group of reactants are radicals, which may be formed by dissociating gases. Dissociation is most conveniently done with a plasma source. For example, dissociating molecular oxygen or hydrogen, oxygen or hydrogen radicals are generated. The use of radicals in ALD may surmount some of the above limitations: oxide film deposition at low temperatures may become feasible if oxygen radicals are used as they are highly reactive. Also, as hydrogen radicals are very effective reducing agents, they may be used to deposit metals. In this work, a plasma source was incorporated in an existing ALD reactor for radical generation, and the reactor was used to study five different Radical Enhanced ALD processes. The modifications to the existing reactor and the different possibilities during the modification process are discussed. The studied materials include two metals, copper and silver, and three oxides, aluminium oxide, titanium dioxide and tantalum oxide. The materials were characterized and their properties were compared to other variations of the same process, utilizing the same metal precursor, to understand what kind of effect the non-metal precursor has on the film properties and growth characteristics. Both metals were deposited successfully, and silver for the first time by ALD. The films had low resistivity and grew conformally in the ALD mode, demonstrating that the REALD of metals is true ALD. The oxide films had exceptionally high growth rates, and aluminium oxide grew at room temperature with low cycle times and resulted in good quality films. Both aluminium oxide and titanium dioxide were deposited on natural fibres without damaging the fibre. Tantalum oxide was also deposited successfully, with good electrical properties, but at slightly higher temperature than the other two oxides, due to the evaporation temperature required by the metal precursor. Overall, the ability of REALD to deposit metallic and oxide films with high quality at low temperatures was demonstrated.

Novel Organo-Noble-Gas Hydrides

Noble gases are mostly known as inert monatomic gases due to their limited reactivity with other elements. However, the first predictions of noble-gas compounds were suggested by Kossel in 1916, by von Antropoff in 1924, and by Pauling in 1930. It took many decades until the first noble-gas compound, XePtF6, was synthesized by Neil Bartlett in 1962. This was followed by gradual development of the field and many noble-gas compounds have been prepared. In 1995, a family of noble-gas hydride molecules was discovered at the University of Helsinki. These molecules have the general formula of HNgY, where H is a hydrogen atom, Ng is a noble-gas atom (Ar, Kr, or Xe), and Y is an electronegative fragment. The first molecular species made include HXeI, HXeBr, HXeCl, HKrCl and HXeH. Nowadays the total number of prepared HNgY molecules is 23 including both inorganic and organic compounds. The first and only neutral ground-state argon compound, HArF, was synthetized in 2000. Helium and neon are the only elements in the periodic table that do not form neutral, ground-state molecules. In this Thesis, experimental preparation of eight novel xenon- and krypton-containing organo-noble-gas hydrides made from acetylene (HCCH), diacetylene (HCCCCH) and cyanoacetylene (HCCCN) are presented. These novel species include the first organic krypton compound, HKrCCH, as well as the first noble-gas hydride molecule containing two Xe atoms, HXeCCXeH. Other new compounds are HXeCCH, HXeCC, HXeC4H, HKrC4H, HXeC3N, and HKrC3N. These molecules are prepared in noble-gas matrices (krypton or xenon) using ultraviolet photolysis of the precursor molecule and thermal mobilization of the photogenerated H atoms. The molecules were identified using infrared spectroscopy and ab initio calculations. The formation mechanisms of the organo-noble-gas molecules are studied and discussed in this context. The focus is to evidence experimentally the neutral formation mechanisms of HNgY molecules upon global mobility of H atoms. The formation of HXeCCXeH from another noble-gas compound (HXeCC) is demonstrated and discussed. Interactions with the surrounding matrix and molecular complexes of the HXeCCH molecule are studied. HXeCCH was prepared in argon and krypton solids in addition to a Xe matrix. The weak HXeCCH∙∙∙CO2 complex is prepared and identified. Preparation of the HXeCCH∙∙∙CO2 complex demonstrates an advanced approach to studies of HNgY complexes where the precursor complex (HCCH∙∙∙CO2) is obtained using photolysis of a larger molecule (propiolic acid).

Atomic Layer Deposition and Photocatalytic Properties of Titanium Dioxide Thin Films

Photocatalytic TiO2 thin films can be highly useful in many environments and applications. They can be used as self-cleaning coatings on top of glass, tiles and steel to reduce the amount of fouling on these surfaces. Photocatalytic TiO2 surfaces have antimicrobial properties making them potentially useful in hospitals, bathrooms and many other places where microbes may cause problems. TiO2 photocatalysts can also be used to clean contaminated water and air. Photocatalytic oxidation and reduction reactions proceed on TiO2 surfaces under irradiation of UV light meaning that sunlight and even normal indoor lighting can be utilized. In order to improve the photocatalytic properties of TiO2 materials even further, various modification methods have been explored. Doping with elements such as nitrogen, sulfur and fluorine, and preparation of different kinds of composites are typical approaches that have been employed. Photocatalytic TiO2 nanotubes and other nanostructures are gaining interest as well. Atomic Layer Deposition (ALD) is a chemical gas phase thin film deposition method with strong roots in Finland. This unique modification of the common Chemical Vapor Deposition (CVD) method is based on alternate supply of precursor vapors to the substrate which forces the film growth reactions to proceed only on the surface in a highly controlled manner. ALD gives easy and accurate film thickness control, excellent large area uniformity and unparalleled conformality on complex shaped substrates. These characteristics have recently led to several breakthroughs in microelectronics, nanotechnology and many other areas. In this work, the utilization of ALD to prepare photocatalytic TiO2 thin films was studied in detail. Undoped as well as nitrogen, sulfur and fluorine doped TiO2 thin films were prepared and thoroughly characterized. ALD prepared undoped TiO2 films were shown to exhibit good photocatalytic activities. Of the studied dopants, sulfur and fluorine were identified as much better choices than nitrogen. Nanostructured TiO2 photocatalysts were prepared through template directed deposition on various complex shaped substrates by exploiting the good qualities of ALD. A clear enhancement in the photocatalytic activity was achieved with these nanostructures. Several new ALD processes were also developed in this work. TiO2 processes based on two new titanium precursors, Ti(OMe)4 and TiF4, were shown to exhibit saturative ALD-type of growth when water was used as the other precursor. In addition, TiS2 thin films were prepared for the first time by ALD using TiCl4 and H2S as precursors. Ti1-xNbxOy and Ti1-xTaxOy transparent conducting oxide films were prepared successfully by ALD and post-deposition annealing. Highly unusual, explosive crystallization behaviour occurred in these mixed oxides which resulted in anatase crystals with lateral dimensions over 1000 times the film thickness.

Parameters Affecting the Extraction of Polycyclic Aromatic Hydrocarbons with Pressurised Hot Water

Pressurised hot water extraction (PHWE) exploits the unique temperature-dependent solvent properties of water minimising the use of harmful organic solvents. Water is environmentally friendly, cheap and easily available extraction medium. The effects of temperature, pressure and extraction time in PHWE have often been studied, but here the emphasis was on other parameters important for the extraction, most notably the dimensions of the extraction vessel and the stability and solubility of the analytes to be extracted. Non-linear data analysis and self-organising maps were employed in the data analysis to obtain correlations between the parameters studied, recoveries and relative errors. First, pressurised hot water extraction (PHWE) was combined on-line with liquid chromatography-gas chromatography (LC-GC), and the system was applied to the extraction and analysis of polycyclic aromatic hydrocarbons (PAHs) in sediment. The method is of superior sensitivity compared with the traditional methods, and only a small 10 mg sample was required for analysis. The commercial extraction vessels were replaced by laboratory-made stainless steel vessels because of some problems that arose. The performance of the laboratory-made vessels was comparable to that of the commercial ones. In an investigation of the effect of thermal desorption in PHWE, it was found that at lower temperatures (200ºC and 250ºC) the effect of thermal desorption is smaller than the effect of the solvating property of hot water. At 300ºC, however, thermal desorption is the main mechanism. The effect of the geometry of the extraction vessel on recoveries was studied with five specially constructed extraction vessels. In addition to the extraction vessel geometry, the sediment packing style and the direction of water flow through the vessel were investigated. The geometry of the vessel was found to have only minor effect on the recoveries, and the same was true of the sediment packing style and the direction of water flow through the vessel. These are good results because these parameters do not have to be carefully optimised before the start of extractions. Liquid-liquid extraction (LLE) and solid-phase extraction (SPE) were compared as trapping techniques for PHWE. LLE was more robust than SPE and it provided better recoveries and repeatabilities than did SPE. Problems related to blocking of the Tenax trap and unrepeatable trapping of the analytes were encountered in SPE. Thus, although LLE is more labour intensive, it can be recommended over SPE. The stabilities of the PAHs in aqueous solutions were measured using a batch-type reaction vessel. Degradation was observed at 300ºC even with the shortest heating time. Ketones and quinones and other oxidation products were observed. Although the conditions of the stability studies differed considerably from the extraction conditions in PHWE, the results indicate that the risk of analyte degradation must be taken into account in PHWE. The aqueous solubilities of acenaphthene, anthracene and pyrene were measured, first below and then above the melting point of the analytes. Measurements below the melting point were made to check that the equipment was working, and the results were compared with those obtained earlier. Good agreement was found between the measured and literature values. A new saturation cell was constructed for the solubility measurements above the melting point of the analytes because the flow-through saturation cell could not be used above the melting point. An exponential relationship was found between the solubilities measured for pyrene and anthracene and temperature.

Sexual reproduction in chydorid cladocerans (Anomopoda, Chydoridae) in southern Finland - implications for paleolimnology

The relationship between sexual reproduction of littoral chydorid cladocerans (Anomopoda, Chydoridae) and environmental factors in aquatic ecosystems has been rarely studied, although the sexual behavior of some planktonic cladocerans is well documented. Ecological monitoring was used to study the relationship between climate-related and non-climatic environmental factors and chydorid sexual reproduction patterns in nine environmentally different lakes that were closely situated to each other in southern Finland. Furthermore, paleolimnological ephippium analysis was used to clarify how current sexual reproduction is reflected in surface sediments of the same nine lakes. Additionally, short sediment cores from two of the lakes were studied with ephippium analysis to examine how recent climate-related and non-climatic environmental changes were reflected in chydorid sexual reproduction. Ephippium analysis uses the subfossil shells of asexual individuals to represent asexual reproduction and the shells of sexual females, i.e. ephippia, to represent sexual reproduction. The relative proportion of ephippia of all chydorid species, i.e. total chydorid ephippia (TCE) indicates the relative proportion of sexual reproduction during the open-water season. This thesis is part of the EPHIPPIUM-project which aims to develop ephippium analysis towards a quantitative climate reconstruction tool. To be able to develop a valid climate model, the influence of the environmental stressors other than climate on contemporary sexual reproduction and its reflection in sediment assemblages must be clarified so they can be eliminated from the model. During contemporary monitoring a few sexual individuals were observed during summer, apparently forced to sexual reproduction by non-climatic local environmental factors, such as crowding or invertebrate predation. Monitoring also revealed that the autumnal chydorid sexual reproduction period was consistent between the different lakes and climate-related factors appeared to act as the main inducers and regulators of autumnal sexual reproduction. However, during autumn, chydorid species and populations among the lakes exhibited a wide variation in the intensity, induction time, and length of autumnal sexual reproduction. These variations apparently act as mechanisms for local adaptations due to the genetic variability provided by sexual reproduction that enhance the ecological flexibility of chydorid species, allowing them to inhabit a wide range of environments. A large variation was also detected in the abundance of parthenogenetic and gamogenetic individuals during the open-water season among the lakes. On the basis of surface sediment samples, the general level of the TCE is ca. 3-4% in southern Finland, reflecting an average proportion of sexual reproduction in this specific climate. The variation in the TCE was much lower than could be expected on the basis of the monitoring results. This suggests that some of the variation detected by monitoring may derive from differences between sampling sites and years smoothed out in the sediment samples, providing an average of the entire lake area and several years. The TCE is always connected to various ecological interactions in lake ecosystems and therefore is always lake-specific. Hypothetically, deterioration of climate conditions can be detected in the TCE as an increase in ephippia of all chydorid species, since a shortening open-water season is reflected in the relative proportions of the two reproduction modes. Such an increase was clearly detected for the time period of the Little Ice Age in a sediment core. The paleolimnological results also indicated that TCE can suddenly increase due to ephippia of one or two species, which suggests that at least some chydorids can somehow increase the production of resting eggs under local environmental stress. Thus, some environmental factors may act as species-specific environmental stressors. The actual mechanism of the increased sexual reproduction seen in sediments has been unknown but the present study suggests that the mechanism is probably the increased intensity of gamogenesis, i.e. that a larger proportion of individuals in autumnal populations reproduce sexually, which results in a larger proportion of ephippia in sediments and a higher TCE. The results of this thesis demonstrate the utility of ephippium analysis as a paleoclimatological method which may also detect paleolimnological changes by identifying species-specific environmental stressors. For a quantitative TCE-based climate reconstruction model, the natural variation in the TCE of surface sediments in different climates must be clarified with more extensive studies. In addition, it is important to recognize the lakes where the TCE is not only a reflection of the length of the open-water season, but is also non-climatically forced. The results of ephippium analysis should always be interpreted in a lake-specific manner and in the context of other paleoecological proxies.

Spatial variation of climate and the impact of disturbances on local climate and forest recovery in northern Finland

The structure and function of northern ecosystems are strongly influenced by climate change and variability and by human-induced disturbances. The projected global change is likely to have a pronounced effect on the distribution and productivity of different species, generating large changes in the equilibrium at the tree-line. In turn, movement of the tree-line and the redistribution of species produce feedback to both the local and the regional climate. This research was initiated with the objective of examining the influence of natural conditions on the small-scale spatial variation of climate in Finnish Lapland, and to study the interaction and feedback mechanisms in the climate-disturbances-vegetation system near the climatological border of boreal forest. The high (1 km) resolution spatial variation of climate parameters over northern Finland was determined by applying the Kriging interpolation method that takes into account the effect of external forcing variables, i.e., geographical coordinates, elevation, sea and lake coverage. Of all the natural factors shaping the climate, the geographical position, local topography and altitude proved to be the determining ones. Spatial analyses of temperature- and precipitation-derived parameters based on a 30-year dataset (1971-2000) provide a detailed description of the local climate. Maps of the mean, maximum and minimum temperatures, the frost-free period and the growing season indicate that the most favourable thermal conditions exist in the south-western part of Lapland, around large water bodies and in the Kemijoki basin, while the coldest regions are in highland and fell Lapland. The distribution of precipitation is predominantly longitudinally dependent but with the definite influence of local features. The impact of human-induced disturbances, i.e., forest fires, on local climate and its implication for forest recovery near the northern timberline was evaluated in the Tuntsa area of eastern Lapland, damaged by a widespread forest fire in 1960 and suffering repeatedly-failed vegetation recovery since that. Direct measurements of the local climate and simulated heat and water fluxes indicated the development of a more severe climate and physical conditions on the fire-disturbed site. Removal of the original, predominantly Norway spruce and downy birch vegetation and its substitution by tundra vegetation has generated increased wind velocity and reduced snow accumulation, associated with a large variation in soil temperature and moisture and deep soil frost. The changed structural parameters of the canopy have determined changes in energy fluxes by reducing the latter over the tundra vegetation. The altered surface and soil conditions, as well as the evolved severe local climate, have negatively affected seedling growth and survival, leading to more unfavourable conditions for the reproduction of boreal vegetation and thereby causing deviations in the regional position of the timberline. However it should be noted that other factors, such as an inadequate seed source or seedbed, the poor quality of the soil and the intensive logging of damaged trees could also exacerbate the poor tree regeneration. In spite of the failed forest recovery at Tunsta, the position and composition of the timberline and tree-line in Finnish Lapland may also benefit from present and future changes in climate. The already-observed and the projected increase in temperature, the prolonged growing season, as well as changes in the precipitation regime foster tree growth and new regeneration, resulting in an advance of the timberline and tree-line northward and upward. This shift in the distribution of vegetation might be decelerated or even halted by local topoclimatic conditions and by the expected increase in the frequency of disturbances.

Joint Regression and Association Models for Repeated Categorical Responses

The focus of this study is on statistical analysis of categorical responses, where the response values are dependent of each other. The most typical example of this kind of dependence is when repeated responses have been obtained from the same study unit. For example, in Paper I, the response of interest is the pneumococcal nasopharengyal carriage (yes/no) on 329 children. For each child, the carriage is measured nine times during the first 18 months of life, and thus repeated respones on each child cannot be assumed independent of each other. In the case of the above example, the interest typically lies in the carriage prevalence, and whether different risk factors affect the prevalence. Regression analysis is the established method for studying the effects of risk factors. In order to make correct inferences from the regression model, the associations between repeated responses need to be taken into account. The analysis of repeated categorical responses typically focus on regression modelling. However, further insights can also be gained by investigating the structure of the association. The central theme in this study is on the development of joint regression and association models. The analysis of repeated, or otherwise clustered, categorical responses is computationally difficult. Likelihood-based inference is often feasible only when the number of repeated responses for each study unit is small. In Paper IV, an algorithm is presented, which substantially facilitates maximum likelihood fitting, especially when the number of repeated responses increase. In addition, a notable result arising from this work is the freely available software for likelihood-based estimation of clustered categorical responses.

Multi-user resource-sharing problem for the Internet

In this thesis we study a series of multi-user resource-sharing problems for the Internet, which involve distribution of a common resource among participants of multi-user systems (servers or networks). We study concurrently accessible resources, which for end-users may be exclusively accessible or non-exclusively. For all kinds we suggest a separate algorithm or a modification of common reputation scheme. Every algorithm or method is studied from different perspectives: optimality of protocols, selfishness of end users, fairness of the protocol for end users. On the one hand the multifaceted analysis allows us to select the most suited protocols among a set of various available ones based on trade-offs of optima criteria. On the other hand, the future Internet predictions dictate new rules for the optimality we should take into account and new properties of the networks that cannot be neglected anymore. In this thesis we have studied new protocols for such resource-sharing problems as the backoff protocol, defense mechanisms against Denial-of-Service, fairness and confidentiality for users in overlay networks. For backoff protocol we present analysis of a general backoff scheme, where an optimization is applied to a general-view backoff function. It leads to an optimality condition for backoff protocols in both slot times and continuous time models. Additionally we present an extension for the backoff scheme in order to achieve fairness for the participants in an unfair environment, such as wireless signal strengths. Finally, for the backoff algorithm we suggest a reputation scheme that deals with misbehaving nodes. For the next problem -- denial-of-service attacks, we suggest two schemes that deal with the malicious behavior for two conditions: forged identities and unspoofed identities. For the first one we suggest a novel most-knocked-first-served algorithm, while for the latter we apply a reputation mechanism in order to restrict resource access for misbehaving nodes. Finally, we study the reputation scheme for the overlays and peer-to-peer networks, where resource is not placed on a common station, but spread across the network. The theoretical analysis suggests what behavior will be selected by the end station under such a reputation mechanism.

Olioarkkitehtuurit peliohjelmistoissa

Tutkielmassa kuvataan peliohjelmistojen toimintoja ja rakenteita ohjelmistoteknisestä näkökulmasta. Pelisovelluksen yleiseksi arkkitehtuuriksi kuvataan MVC-arkkitehtuurimalliin perustuva ratkaisu, joka käyttää viestinvälitysjärjestelmää sovelluksen osajärjestelmien väliseen kommunikaatioon. Tutkielmassa esitellään peliohjelmistoissa tarvittavan reaaliaikaisen kolmiulotteisen grafiikan menetelmiä sekä avoimeen lähdekoodiin perustuva Ogre-grafiikkakomponentti. Suunnitteluratkaisujen ja menetelmien toimivuutta testataan suunnittelemalla ja toteuttamalla prototyyppi kehysmäisestä peliohjelmistosta. Tutkielman lopuksi esitetään analyysi peliohjelmistoihin suositeltavista suunnitteluratkaisuista, kuten peliobjektien komponenttiperustaisesta mallinnuksesta. Tutkielman konstruktiivisen osuuden tuloksena syntyi tyypitetty viesti -suunnittelumalliin pohjautuva suunnitteluratkaisu ohjelmiston sisäisen viestinvälityksen toteuttamiseen.

Förutsättningarna för psykiatrisk vård oberoende av patientens vilja och patientens rättsskydd vid fattandet av vårdbeslutet

I arbetet analyseras de i mentalvårdslagen (1990/1116) stadgade förutsättningarna för psykiatrisk sjukhusvård oberoende av patientens vilja gällande myndiga patienter för vilka inte har utsetts en intressebevakare före fattandet av vårdbeslutet, samt bakgrunden till och en del av de svårigheter som förknippas med denna form av vård och härtill anknutet beslutsfattande. Problemen tillspetsas framförallt i situationer av intressekonflikt mellan patientens intressen respektive samhällets intressen. Utgångspunkten ligger främst i finländsk mentalvårdslagstiftning och rättspraxis, men för att på ett ändamålsenligt sätt kunna redogöra för bakgrunden till och förutsättningarna för dylikt förvaltningsrättsligt beslutsfattande görs även relevanta kopplingar till medicinska (psykiatriska) yrkesetiska riktlinjer och mentalvårdslagstiftning inom övriga Norden. Analysen omfattar även den Europeiska människorättsdomstolens praxis i fall som gäller frihetsberövande på basis av psykiatrisk vård, närmare bestämt artikel 5 (1)(e) i den europeiska människorättskonventionen. Patientens självbestämmanderätt, frihet och integritet är utgångspunkterna för alla slags vårdförhållanden. Dessa inbegriper bl.a. frivillighet och informerat samtycke då en person söker vård. Möjligheten att förordna en person till psykiatrisk vård oberoende av dennes vilja är ett lagstadgat undantag till dessa principer. Beslutsfattandet är bundet till strikta lagstadgade förutsättningar, vilkas bedömning kräver juridisk, men framförallt medicinsk kunskap, vilket också skapar gränser och utmaningar för de yrkespersoner som arbetar med dylika ärenden. Kombinationen av psykiatri, etik och juridik är nödvändig, men inte alltid enkel att göra, vilket märks inte minst på terminologin som tillämpas i mentalvårdslagstiftningen. I arbetet analyseras en del av den terminologi som tillämpas inom finsk och övrig nordisk mentalvårdslagstiftning. Syftet är att visa att definitionerna, tolkningarna, terminologin och synsättet på psykisk ohälsa som tillämpas inom den finländska mentalvårdslagstiftningen jämförelsevis kanske inte är de mest lämpliga eller tidsenliga. En annan svår uppgift, som framförallt lagstiftaren ställ(t)s inför, är utformningen av mentalvårdslagstiftning som är tillräckligt flexibel för att tillåta beaktande av särdragen i varje enskilt ärende, men som samtidigt är strikt nog för att förhindra godtycke och missbruk. En person som lider av allvarlig psykisk ohälsa befinner sig oftast i en ytterst utsatt position, och är ofta begränsat eller inte alls kapabel att göra en korrekt bedömning av sig själv och sin situation. Således sker den starka betoningen av patientens självbestämmanderätt på både gott och ont. Det är kanske inte alltid i en psykiatrisk patients bästa att få bestämma själv, vilket också är en av frågorna som omfattas av analysen i arbetet. Eftersom det psykiatriska vårdbeslutet till karaktären är ett (skriftligt) förvaltningsbeslut, skiljer det sig samtidigt från övrigt beslutsfattande inom vårdsektorn, vilket till största delen utgör faktisk förvaltningsverksamhet. För patienten innebär vårdbeslutet också ett administrativt frihetsberövande. Ingreppet i patientens grundläggande fri- och rättigheter är särskilt stort och upplevs ofta som mycket kränkande, och därför ställs särskilt strikta krav på iakttagande av det lagstadgade beslutsförfarandet och vårdförutsättningarna samt tillgodoseendet av patientens rättsskydd. Den offentliga hälso- och sjukvården är verksamhet som är underställd den offentliga förvaltningen, vilket innebär att de allmänna förvaltningsrättsliga rättsskyddsgarantierna är tillämpliga. I och med vårdbeslutets karaktär av förvaltningsbeslut, kan ändring i beslutet sökas genom besvär hos förvaltningsdomstolen. Dessa är också några av de frågor som behandlas i arbetet.

Käytännöt ja ajattelu Michel Foucault'n filosofiassa

Practices and Thought in Michel Foucault s Philosophy The present thesis examines Michel Foucault s (1926-1984) notion of practice and argues that it is an essential concept in his philosophy, especially in his analysis of knowledge, power and ethics. The thesis reveals a previously neglected chronological and methodological unity in Foucault s work. The first chapter clarifies Foucault s philosophy by outlining it according to four central themes. First, the main philosophical goal of his historical studies is to analyse how human subjects have become objects of their own thinking. Second, this goal calls for methodological precaution to avoid all anthropological universals. Third, Foucault s studies are directed towards fields of practices. Fourth, the analysis of practices is executed along three axes: knowledge, power and ethics. The second chapter concerns the notion of practice in Foucault s archaeological method. Foucault s archaeological analysis is not directed towards objects and subjects as such, but to the way that the rules of discursive practice form them in the discourse. Many commentators have neglected Foucault s concept of practice when discussing his ideas concerning rules of discourse and limits of knowledge. I argue that Foucault s analysis concerning the limits of knowledge relates to local and contingent rules of discursive practice, not to transcendental rules of thinking in general. The third chapter deals with power relations and practices. I clarify Foucault s concept of dispositif by defining it as a functional ensemble of practices, and argue that this concept is crucial to his understanding of power relations. I stress a conceptual definition, which separates relations of power from the practices of government and show that the latter is based on the idea that power relations are integrated into practices. This conceptual clarification also helps in understanding Foucault s critique concerning modern practices of power. The fourth chapter examines Foucault s way of perceiving ethics as a practice. He separates three essential dimensions in morals: moral codes, moral behaviour and practices of self. His ethics concern practices of self and he studies how these practices have constituted different relations that subjects have to themselves, to others and to their societies. I argue that Foucault s own ethical views can be found in the ideas on the importance of practices of self in the modern world, and emphasize that these ideas should be connected to his views concerning the tradition of the Enlightenment, and to his own political action.

Religion Explained? : A Philosophical Appraisal of the Cognitive Science of Religion

This study examines philosophically the main theories and methodological assumptions of the field known as the cognitive science of religion (CSR). The study makes a philosophically informed reconstruction of the methodological principles of the CSR, indicates problems with them, and examines possible solutions to these problems. The study focuses on several different CSR writers, namely, Scott Atran, Justin Barrett, Pascal Boyer and Dan Sperber. CSR theorising is done in the intersection between cognitive sciences, anthropology and evolutionary psychology. This multidisciplinary nature makes CSR a fertile ground for philosophical considerations coming from philosophy of psychology, philosophy of mind and philosophy of science. The study begins by spelling out the methodological assumptions and auxiliary theories of CSR writers by situating these theories and assumptions in the nexus of existing approaches to religion. The distinctive feature of CSR is its emphasis on information processing: CSR writers claim that contemporary cognitive sciences can inform anthropological theorising about the human mind and offer tools for producing causal explanations. Further, they claim to explain the prevalence and persistence of religion by cognitive systems that undergird religious thinking. I also examine the core theoretical contributions of the field focusing mainly on the (1) “minimally counter-intuitiveness hypothesis” and (2) the different ways in which supernatural agent representations activate our cognitive systems. Generally speaking, CSR writers argue for the naturalness of religion: religious ideas and practices are widespread and pervasive because human cognition operates in such a way that religious ideas are easy to acquire and transmit. The study raises two philosophical problems, namely, the “problem of scope” and the “problem of religious relevance”. The problem of scope is created by the insistence of several critics of the CSR that CSR explanations are mostly irrelevant for explaining religion. Most CSR writers themselves hold that cognitive explanations can answer most of our questions about religion. I argue that the problem of scope is created by differences in explanation-begging questions: the former group is interested in explaining different things than the latter group. I propose that we should not stick too rigidly to one set of methodological assumptions, but rather acknowledge that different assumptions might help us to answer different questions about religion. Instead of adhering to some robust metaphysics as some strongly naturalistic writers argue, we should adopt a pragmatic and explanatory pluralist approach which would allow different kinds of methodological presuppositions in the study of religion provided that they attempt to answer different kinds of why-questions, since religion appears to be a multi-faceted phenomenon that spans over a variety of fields of special sciences. The problem of religious relevance is created by the insistence of some writers that CSR theories show religious beliefs to be false or irrational, whereas others invoke CSR theories to defend certain religious ideas. The problem is interesting because it reveals the more general philosophical assumptions of those who make such interpretations. CSR theories can (and have been) interpreted in terms of three different philosophical frameworks: strict naturalism, broad naturalism and theism. I argue that CSR theories can be interpreted inside all three frameworks without doing violence to the theories and that these frameworks give different kinds of results regarding the religious relevance of CSR theories.

Kertomuksia kirkon työntekijäksi kasvamisesta : Kirkon nuorisotyötä opiskelevien spiritualiteetin ja ammatillisen identiteetin muotoutuminen

The aim of the study was to analyse Church Youth Work Leader students different processes of developing their spirituality and professional identity. The study was carried out in connection with the church-orientated education at the Diaconia University of Applied Sciences (Diak). The method of the study was narrative analysis. The data consisted of stories written (N=46) and told (N=10) by students, that were collected over three years in two units of Diak. The data was analysed in two ways: first with categorical-content analysis, and then with holistic-content analysis and holistic-form reading in order to establish the comprehensive views of complete narratives. The theoretical starting-point was to regard spirituality widely, including religion and faith. In the first data analysis, this theory was focused so that spirituality was namely Christian spirituality including personal faith and worship, membership in the Christian community and persons values and ideas about the meaning of life. The results of the investigation were presented in five model narratives. The story of a social care worker represents the process of a student orientating to social work. In this story spirituality manifested as a part of social and personal identity but not as a part of professional identity. The vocation for helping people led the student to social care work. In the story of a counselor, students good connection to their home parish took a central role. They had good experiences working as young Christian volunteers, and during their studies this volunteer role became professional role. Spirituality was strongly joined to professional identity. The story of an educator represents a vocation for spiritual work and youth work in the church. In this story students also had good connections to their home parishes. Spirituality manifested as a part of personal, social and professional identity. In the story of a spiritual worker or preacher, each person s spiritual vocation was remarkable. Spirituality was extremely individual and it defined the personal, social and professional identity. Spiritual devotion caused a change in students orientation from the church to social services. The story of a searcher tells about a student who is still looking for her or his own profession. The focus of the story was on personal growth and considering one s values and the meaning of life. Spirituality was manifested in personal identity. The results indicate that the practical placements in the second academic year have an important effect on students professional orientation and professional identity. The connection to the local parish has also significant meaning for students spiritual formation and development into church professions.