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Security of web communication is crucial. When accessing an online bank, for example, one of the key issues is that the user can be assured they are communicating with the bank as they intended to. This assurance is achieved with the public key infrastructure for the Web, Web PKI. Its purpose is to manage digital certificates on the Web. Certificates are used to prove one’s identity with the help of public-key cryptography. Certificate authorities and software vendors that operate certificate root stores have key roles in the Web PKI. The first issue certificates and the latter choose which CAs are trusted. The Web PKI has multiple challenges and it is a highly researched topic. Numerous countermeasures and enhancements to the Web PKI have been developed over the years. This thesis investigates challenges in the Web PKI and proposed countermeasures, some of which are based on blockchain technology. Of the non-blockchain-based solutions, we introduce Certificate Transparency, CAA and DANE. Of the blockchain-based solutions, CertLedger, IKP and a solution for decentralising ACME protocol are described. We find that the challenges are mainly related to certificate authorities, revocation and root stores. From the numerous solutions, Certificate Transparency and CAA are utilised in the Web PKI. Shortening the validity period of certificates can resolve some of the challenges. Blockchain-based solutions are numerous but none has yet seen wide deployment.

With increasing amounts of software services provided to users and the more demanding requirements needed from them, monitoring of services is becoming increasingly important. Web service monitoring is the process of confirming system functionality by studying its various attributes, such as availability, reliability, and performance. Monitoring the services helps the software developers, maintainers and owners as they allow for increased reliability, robustness and possibly performance analysis. This thesis focuses on web service monitoring and the tools that it is done with. Specific goals are to learn about the different categories that monitoring services can take and to showcase a custom web service monitoring tool and its further development. The subject is important to the case company LogiNets, which has specific monitoring requirements that need to be fulfilled. These goals were achieved by researching literature on different types of monitoring tools for a literature review and then doing a case study of monitoring tool development. The case study was done about adding a new functionality to LogiNets’s indoor web service monitoring tool called Agent. The literature review was successful in identifying different categories of monitoring tools both by their location relative to the monitored service as well as by the quality of service requirements they fulfill. The review did not, however, discover significant research about existing commercial monitoring tools, and thus provided little help in the case study. The case study was more successful, with the new functionality added and similar extensions planned for the future.

Ketterässä ohjelmistokehityksessä laadunhallinnan perustana ovat laadukkaat ohjelmistokehityskäytännöt sekä automaattinen testaus. Automaattinen testaus on ennen kaikkea kohdistunut yksikkötestaukseen, jolla pyritään varmistamaan ohjelmiston sisäistä laatua. Toiminnallinen testaus ja hyväksymistestaus ovat myös automatisoitavissa, mutta niiden automatisointia ovat hidastaneet kustannukset sekä testien vaatima ylläpito. Toiminnallisen testauksen automatisointiin on kehitetty työkaluja sekä menetelmiä, joiden avulla voidaan kustannustehokkaasti toteuttaa automatisoituja toiminnallisia testitapauksia. Jatkuva integraatio on yleensä automaattisen yksikkötestauksen pohjana ketterässä kehityksessä ja osana jatkuvaa integraatiota on myös mahdollista automatisoida toiminnallinen testaus. Automaattisen toiminnallisen testauksen kustannuksiin voidaan vaikuttaa valituilla testauskehyksillä, testitapausten suunnittelulla sekä toteuttamalla testitapauksia hyväksi todettujen käytäntöjen mukaan. Toiminnallinen testaus perustuu toiminnallisiin vaatimuksiin, joten käyttötapaukset ja käyttäjätarinat ketterässä kehityksessä sekä niiden hyväksymiskriteerit auttavat testitapausten suunnittelussa ja toteutuksessa. Testitapaukset ovat helposti toteutettavissa nauhoita-ja-toista -menetelmällä ja refaktoroimalla testitapauksista selkeämpiä. Esimerkiksi sivuobjekti -suunnittelumallin mukaisilla testitapauksilla voidaan pienentää testauksen ylläpidon kustannuksia. Testauskehyksiä on tarjolla automaattisen testauksen eri menetelmiin, jolloin automaattinen toiminnallinen onnistuu myös erilaisissa kehitysympäristöissä. ACM Computing Classification System (CCS): Software and its engineering → Software verification; Agile software development; Software testing and debugging; Documentation;

The Weddell Sea on the Antarctic coast is one of the most important areas of deep-water formation in the oceans. The processes that result in deep-water formation depend on the sea area's oceanic transport mechanisms and on the climatological conditions. The primary purpose of this master’s thesis is to calculate the prevailing current conditions and to estimate changes in the water-mass properties in the Weddell Sea. This was performed by using hydrographic data collected during the SWEDARP 88/89 expedition. The first part of the thesis includes a literature study on the oceanographic conditions in the Weddell Sea. The study describes the conditions that regulate the Weddell Sea's circulation field and characteristic oceanographic processes. Transport calculations were performed by applying geostrophic methodology to data from the station network in the southwestern Weddell Sea. First, the baroclinic flow field was determined with the assumption that the cyclonic circulation of the Weddell Sea flows in a clockwise direction through each transect of the gyre. The barotropic component of the current field was then calculated using an inverse method which balances the transports through the measurement transects by meeting given criteria. These were that the transport of salt and mass is equal through each measurement transect. The total volume transport in the Weddell gyre was calculated to be about 19 Sverdrup (1 Sv = 10^6 m^3/s), which is about 60% of the transport estimated in the literature. The formation of Weddell Sea Bottom Water (WSBW) was estimated to 1.4 Sv. The primary result of the study was the amount of heat released from the water column to the atmosphere within the measurement area. The heat loss was calculated to 12 TW (terawatt). The unique SWEDARP 88/89 stations measured in the Filchner depression on the continental shelf would deserve further analysis and would enrich the studies of the global deep-water circulation.

The field of superhydrophobicity i.e. extreme water-repellency is a fast growing one ever since artificial ways of manufacturing such surfaces have been developed. Superhydrophobic surfaces have several potential applications including surfaces that are self-cleaning, corrosion and stain resistant, anti-fogging and anti-fouling. For the use of superhydrophobic surfaces in applications there is a need for a precise characterization of their wetting properties. However, conventional methods for characterization have several drawbacks when applied to superhydrophobic surfaces. This has resulted in a need to develop new method for characterizing wetting properties of superhydrophobic surfaces. This thesis presents one auspicious method for wetting characterization of ultra water-repellent surfaces along with the theory the method is based on. In the method a magnetic water droplet is forced to oscillate on the superhydrophobic surface. The friction affecting droplet during oscillations is proportional to the wetting degree of surface. Furthermore, using a moving droplet allows the investigation of dynamic wetting properties of superhydrophobic surfaces.

The decathlon is a track and field event that consists of ten single events, which are performed in the same order during two competitive days. The result from each event is according to the official scoring table transformed into points which are then added together and result in the final score. The aim of this study is to see, what makes an elite decathlete. The individual development in each event is observed. For this study material consisting of all recorded data by decathletes with a personal best of over 8 500 points from year 1970 to 2019 have been used. From the data the best (individual) results made within a decathlon per year was chosen up until the best season. Changes in the decathlete´s profile has been analyzed in four stages (clusters). Changes in the individual development pattern based on the initial level in each event is also observed. The theory part covers the linear mixed-effects model introduced by Laird and Ware. The restricted maximum likelihood method related to the model is deduced in detail. According to the results of the study it seems like the sprint events are of great importance in the decathlon. Especially initially weak 400-meter-runners make a notable progress. However, some initially weak events remain relatively weak compared to the initially stronger.

In the industry categorization, construction industry is one of the largest sources of waste and greenhouse gas emissions. Construction industry, with norms, practices, business models, and legislation connected to it, is built on linear foundations. In a linear economy, energy and material flows are based on value addition and a take-make-use-dispose logic. The circular economy is pursued as a replacement to the linear economic model and is based on the idea of value preservation. Among several other sustainability-driven concepts, the use of the concept of circular economy is growing in local, national and international level environmental governance. This thesis is located in the complex and ambiguous conceptual framework of circular economy as a sustainability transformation in municipal politics. The subjects under observation are four Finnish cities: Helsinki, Joensuu, Turku, and Vantaa. I aim to gain an understanding of why circular economy policy implementation in the construction and demolition of buildings seems inadequate in comparison to the municipalities’ circular economy and sustainability ambitions and whether it really is so. The current city strategies, the policy documents with the most significant guiding impact to circular construction, and interviews with experts from the municipalities and construction sector are analyzed with thematic analysis. This thesis is a part of a six-year transdisciplinary research project, DeCarbon-Home, which studies and co-develops solutions to the just sustainability transitions of living and construction. The results of this thesis show that the understanding and awareness of the concept of circular economy and ambitions attached to it vary significantly not only between cities but also within. The cities are in different phases of circular economy transition, and the results demonstrate various pathways of policy implementation. Some shared challenges that are so far hindering the cities from implementing circularity in construction have to do with the lock-in with the current linear system, division of ownership and responsibility, communication, timing, and paradigm shift.

Tutkielman aiheena oleva Whitneyn upotuslause osoittaa todeksi sen intuitiivisen ajatuksen, että jokainen sileä monisto voidaan upottaa johonkin euklidiseen avaruuteen. Lause on nimetty Hassler Whitneyn mukaan, joka ensimmäisenä todisti sen vuonna 1936. Tutkielma jakautuu kolmeen lukuun, joista ensimmäisessä käymme lävitse tarpeellisia yleisen topologian käsitteitä ja niistä johdettuja lauseita aloittaen tärkeimmistä eli topologisen avaruuden ja kuvauksen jatkuvuuden määritelmistä. Esiteltäviin käsitteisiin kuuluvat lisäksi esimerkiksi homeomorfismi, topologinen upotus, topologian kanta, aliavaruudet ja yhtenäisyys. Luvun lopuksi tutustutaan kompaktiuteen, joka on tutkielman kannalta suuressa osassa, koska sitä käytetään myöhemmin Whitnyeyn upotuslauseen todistuksessa. Toisessa luvussa keskitytään sileiden monistojen teoriaan siinä laajuudessa kuin se tutkielman kannalta on tarpeen. Luvun aluksi määritellään monisto, joka on numeroituvan kannan omaava, lokaalisti euklidinen Hausdorffin avaruus. Sen jälkeen määritellään monistolle sileä rakenne, eli maksimaalinen sileä kartasto, jonka avulla monistosta saadaan sileä monisto. Molemmista edellä mainituista annetaan useita esimerkkejä. Lisäksi todistetaan monistojen ja sileiden monistojen ominaisuuksia. Erityisesti todistetaan esikompaktien kantojen olemassaolo kaikille monistoille. Tämän jälkeen määritellään slieä ykkösen ositus ja todistetaan sen olemassaolo sileille monistoille. Käyttäen edellistä voidaan todistaa sileiden töyssy- ja tyhjennysfunktioiden olemassaolo sileille monistoille. Näitä funktioita käytetään myöhemmin Whitneyn upotuslauseen todistuksessa. Seuraavaksi määritellään monistojen välinen sileä kuvaus ja sen jälkeen derivaatio, tangenttivektori ja tangenttiavaruus, joiden avulla voidaan määritellä sileän kuvauksen differentiaali. Tämän jälkeen siirrytään sileän immersion määritelmään, joka tehdään dfferentiaalin avulla. Sileän immersion avulla saadaan sitten määriteltyä sileä upotus. Luvun viimeisessä osiossa määritellään alimonistot ja niihin liittyvät tasojoukot. Erityisesti määritellään vielä kriittiset pisteet ja arvot. Kolmannessa ja viimeisessä luvussa todistetaan ensin joitain aputuloksia ja sen jälkeen Sardin lause, jota käytetään myöhemmin Whitneyn upotuslauseen todistamiseen. Sardin lauseen mukaan sileiden monistojen välisen sileän kuvauksen kriittisten arvojen joukko on nollamittainen. Tämän jälkeen todistetaan vielä kaksi aputulosta ennen Whitneyn upotuslauseen todistusta. Näistä jälkimmäisessä osoitetaan, että jos on olemassa sileä upotus sileältä n-monistolta jollekin euklidiselle avaruudelle, niin on olemssa sileä upotus avaruudelle R2n+1. Näiden jälkeen päästään todistamaan tutkielman päätulos Whitneyn upotuslause, jonka mukaan jokaisella reunallisella tai reunattomalla sileällä n-monistolla on olemassa vahva sileä upotus euklidiseen avaruuteen R2n+1. Todistus jakautuu kahteen osaan, joissa ensimmäisessä todistetaan tapaus, jossa sileä monisto on kompakti. Tämä tehdään rakentamalla sileä upotus sileän töyssyfunktion avulla. Todistuksen toisessa osassa jaetaan ei-kompakti sileä monisto kompakteihin alimonistoihin tyhjennysfunktion avulla. Tämän jälkeen näiden sileät upotukset yhdistetään töyssyfunktion avulla uudeksi koko moniston peittäväksi sileäksi upotukseksi.

Urban development causes a decline of biodiversity, which is alarming as it is crucial for the health of urban nature as well as urban residents. The latter play an important role in the conservation of biodiversity, as they have to accept it. While previous studies have used single attributes and smaller samples to examine whether and how people know about biodiversity, little attention has been paid to place-based perceptions in a more holistic manner at the city level and with including different perception attributes. This study is a secondary analysis of data collected through public participation geographic information system (PPGIS) in Helsinki, Finland, as part of the CO-CARBON project and aims to understand how perceptions of high biodiversity vary between different age groups considering the type of green space, the frequency of access to different green spaces, the distance of perceived high biodiversity from home, and the location of high biodiversity. I analyzed responses of younger (n1 = 290, aged 16-39), middle-aged (n2 = 286, aged 40-52), and older (n3 = 283, aged 53-98) residents of Helsinki using geographical information systems (QGIS and ArcGIS) for spatial and statistical package for social sciences (SPSS) for non-spatial analyses. Statistical significances of the different variables were tested with multivariate analysis of variance (MANOVA), Chi-square tests, Spearman rho, and optimized hotspot analysis. Some differences, but also similarities, could be found between age groups in their perception of high biodiversity. The age groups are similar in the number of mapped points in terms of green space type, as they mostly perceived natural green spaces as high in biodiversity, but older people differed from the others in terms of frequency of access to green space types, while younger people differed in terms of marking high biodiversity further away from home. Notably, all age groups perceived central bigger green areas, especially Vanhankaupunkilahti, the most as high in biodiversity. Younger people formed the most spatial hotspots of perceptions of high biodiversity, as well as a coldspot at Malmi airport, while the oldest age group formed the fewest hotspots. As a consequence of these results, I discuss and conclude what measures through which media tools could be taken in order to achieve more knowledge and involvement of biodiversity conservation. Further research on perception of biodiversity will benefit from understanding what was understood to be biodiverse at the mapped location, examining other groups, studying effective communication of biodiversity issues and conservation events, looking at biodiversity opposed to high biodiversity, and examining the biodiversity perception of wetland and urban green spaces in more detail.

WikiMage is an online web game based on Wikipedia which is a free, collaboratively edited, and multilingual Internet encyclopedia. The name WikiMage is a combination of Wikipedia and Image that implies the game is built on those images referenced by Wikipedia articles. The WikiMage will challenge the players in terms of their width and depth of knowledge. During the game, a large number of pictures will be presented, and only the player who is able to distinguish the potential relationships between those images can win the game. It is deployed in CoSCo Demos server. By the time this article is composed, WikiMage is accessible through its URL.