Estimering av berggrunns sedimenttykkelse med Kriging vs. Maskinlæringsmodeller

Denne avhandlingen hadde som mål å finne de beste regresjonsmetodene for å estimere berggrunnens sedimenttykkelse rundt Årungen, ved å sammenligne Kriging Interpolering med Maskinlæring-metoder. Nøyaktig modellering er viktig i flere samfunnsutfordringer, inkludert; å finne grunnvanns lokasjoner, produksjon av geotermisk varme og sikkerhet for infrastruktur i byplanlegging. Vi forsøkte å finne modellene som var best utstyrt for ulike mål, inkludert: Hvilken modell (1) gir de beste prediksjons målingene, (2) har de mest stabile resultatene med den laveste prediksjons variasjonen, (3) gir de mest realistiske prediksjons-overflatene, og (4) er den mest praktiske? GRANADA borehulls database, NADAG borehull, digitale løsmassekart og Kartverket digitale høydedata-modeller ble brukt for å lage nøyaktige data. Semivariogram tilpasning og parameter justering ble brukt på flere implementeringer av Kriging, for å optimalisere deres ytelse. Et representativt utvalg av Maskinlæring-regresjonsmodeller ble brukt og optimalisert ved hjelp av grid-søk-metoden. Det ble gjennomført flere runder med kryssvalidering for å sikre trygghet til resultatene. KNN-modellene forklarte 67% variansen, men med dårlige prediksjons overflater. Modellene Kriging og XGBoost var i stand til å forklare 64% av variansen med sine prediksjoner, samtidig som de hadde realistiske prediksjons-overflater. Kriging-interpolasjonsmetoden kom ut på topp i de fleste av bedømmelseskriteriene, med XGBoost på andreplass. Basert på våre data og metoder som er brukt, konkluderer vi med at Kriging fortsatt er det beste innen overflate regresjon.This thesis aimed to find the best regression methods to estimate the bedrock sediment thickness around Lake Aarungen, by comparing Kriging Interpolation to Machine Learning methods. Accurate modeling is important in several challenges within society, including; finding groundwater locations, production of geothermal heat, and the safety of infrastructure in urban planning. We attempted to find the models best equipped for unique goals, including: What model (1) gives the best prediction performance metrics, (2) has the most stable results with the lowest prediction variation, (3) produces the most realistic prediction surfaces, and (4) is the most practical? GRANADA borehole database, NADAG drill holes, Digital Query Maps, and Kartverket Digital Elevation models were used to create accurate data. Semivariogram fitting and parameter tuning was used on several implementations of Kriging, to optimize their performances. A representative selection of Machine Learning regression models was used and optimized using grid search. Several rounds of cross-validation were conducted to ensure confidence in the results. The KNN models explained 67% of variance, although with poor prediction surfaces. The models of Kriging and XGBoost were able to explain 64% of the variance with their predictions, while having realistic prediction surfaces. The kriging interpolation method came out on top in most of the judging criteria, with XGBoost second. Based on our data and methods used, we conclude that Kriging remains the state-of-the-art in surface regression

Bidrar BREEAM-NOR sertifiseringen til at det forekommer færre endringsmeldinger i byggeprosjekt der sertifiseringssystemet anvendes, sammenlignet med konvensjonelle byggeprosjekt?

Klimautfordringer er et verdensomspennende problem, og eiendom- og byggebransjen står for 40% av klimagassutslippene globalt. Et tiltak som kan være med på å redusere dette utslippet, er å benytte miljøsertifiseringssystemer som vurderer miljøytelsen til bygg. BREEAM (Building Research Establishment Environmental Assessment) er en av de mest anerkjente miljøsertifiseringssystemene i verden, og vurderer bygg ut ifra ni bærekraftskategorier. Det finnes ulike landstilpasninger av BREEAM, der BREEAM-NOR er tilpasset norske forhold. For å kunne benytte systemet er man nødt til å betale sertifiseringskostnader, noe som har ført til at færre har mulighet til å benytte systemet. BREEAM-NOR bidrar til å planlegge for hva slags tiltak som kan gjøres for å redusere miljøpåvirkningen til et bygg. Siden sertifiseringssystemet setter fokus på planlegging, vil man kunne tenke at dette fører til et mindre behov for å endre bygget underveis. Å fravike fra det som er blitt planlagt, er fordyrende og tidsforlengende. Hvis noe må endres er man nødt til å sende inn en endringsmelding om det det gjelder, noe som alltid bidrar til tilleggsutgifter. I denne oppgaven undersøkes det om det forekommer færre antall endringsmeldinger i BREEAM-NOR sertifiserte bygg sammenlignet med konvensjonelle bygg. For å besvare denne problemstillingen har jeg først gjennomført kvalitative intervjuer med ulike aktører i bransjen som har erfaring med både konvensjonelle byggeprosjekt og BREEAM-NOR sertifiserte byggeprosjekt. Etter disse intervjuene fikk jeg tilsendt excel-oversikter over alle endringsmeldinger som er forekommet i de ulike byggeprosjektene aktørene har vært involvert i. Ut ifra dette utførte jeg en kvantitativ undersøkelse der jeg hadde muligheten til å kartlegge om det faktisk foreligger noen korrelasjon mellom BREEAM-NOR og antall endringsmeldinger i byggeprosjekter. Denne oppgaven viser at det ikke foreligger noen studier på problemstillingen fra tidligere, og at dette er et eksisterende kunnskapshull i forskningen i dag. Undersøkelsen av problemstillingen viser at det forekommer færre endringsmeldinger som kan relateres til bærekraftskategoriene i BREEAM-NOR, og at bruken av BREEAM-NOR totalt sett bidrar til en reduksjon av antall endringsmeldinger i et byggeprosjekt

Urban kultur - Sted, identitet og tilhørighet i en globalisert verden

Verden og samfunnet preges av hyppige endringer som øker i hastighet. Overgangen fra et industrielt samfunn til et informasjons- og kunnskapssamfunn har endret byenes rolle fra å være møteplasser og smeltedigler av kulturer, til strukturer der tradisjonell funksjonalitet kan synes å tilhøre fortiden. Samtidig har samfunnet blitt mer mangfoldig, med så mye som 80% av Norges befolkning bosatt i urbaniserte områder. Denne utviklingen fremhever nye utfordringer og muligheter. Midt i disse endringene synes identitet å bli nedprioritert. Oppgaven adresserer hvordan byens mange identiteter og kulturer påvirkes av å ikke være en del av utformingen av stedene vi bor på. Den utforsker fenomenet "urban kultur" og hvordan de mange unike identitetene i byenes mangfoldige landskap får uttrykt seg og bidrar til å skape fellesskap som reflekterer dette mangfoldet. Studien utforsker hvordan sosiale, kulturelle og romlige uttrykk i ulike bymiljøer manifesterer seg som kollektiv stedsidentitet over tid, og hvordan lokal identitet kan bevares og fremmes i en stadig mer globalisert verden. Det undersøkes hvordan byområder formes og påvirkes av lokalsamfunnets sosiale og kulturelle adferd, samt hvordan disse adferdsmønstrene kan bli begrenset av byområdenes struktur, demografi og kontroll. Ved hjelp av et tverrfaglig kunnskapsgrunnlag, flere stedsanalyser og en tredelt dokumentanalyse, analyseres mulighetene og utfordringene som dagens planlegging, samfunnsmessige forhold, politikk, markedskrefter og miljøpsykologi stiller, med mål om å avdekke hvordan befolkningen kan manifestere særpreg i sine nabolag gjennom strategier og planleggingsføringer. Til slutt søker oppgaven å forstå den komplekse dynamikken som former våre urbane miljøer, og hvordan urban kultur kan påvirke og forsterke urbane utviklingsprosesser. Dette gjøres for å fremme mer levende, inkluderende og identitetsrike nabolag. Ved å vurdere hvordan innbyggere kan få en sterkere stemme i byutviklingen, utforskes mange ulike perspektiver som belyser et tidligere lite beskrevet fenomen i et forsøk på å demokratisere medvirkning i byplanlegging. Studien peker mot en trend der sosiale hensyn vektlegges mindre i motstridende hensyn, og at mange steder planlegges for å være attraktive i en internasjonal sammenheng. Oppgaven utforsker derfor hvordan vi kan planlegge med kulturen på en måte som respekterer og fremmer lokale identiteter.The world and society are marked by rapid changes, which appear to be accelerating. As society transitions from an industrial to an information and knowledge-based society, the traditional role of cities as meeting places and cultural melting pots seems to belong to the past. However, society has become more diverse than before, with as much as 80% of Norway's population now living in urban areas. Amidst these changes, one particular aspect seems to have been significantly overlooked or downplayed: identity. What happens when the many identities and cultures of a city do not participate in shaping the spaces we inhabit? This thesis seeks to understand the phenomenon of "urban culture." How do the various unique identities within the diverse landscapes of cities express themselves and contribute to creating a community that reflects this diversity? By exploring how the social, cultural, and spatial expressions in different urban environments manifest as collective place identity over time, this study aims to highlight how local identity can find its place in a global world. The thesis investigates how urban areas can be shaped and controlled by the social and cultural behaviors of local communities, and how these behaviors can be limited by the structure, demographics, and governance of urban areas. Utilizing an interdisciplinary knowledge base, multiple place analyses, and a three-part document analysis, this thesis examines the opportunities and challenges posed by current planning, societal conditions, politics, market forces, and environmental psychology concerning the population's ability to manifest uniqueness. Employing photography combined with theory to uncover opportunities and challenges, and by evaluating these findings against development strategies and guidelines, the thesis seeks to illuminate the scope for communities to influence their neighborhoods. In an effort to understand the infinite complexity that shapes and determines our urban environments, the thesis explores how urban culture can shape and enhance urban development processes to promote more vibrant, inclusive, and identity-rich neighborhoods in an increasingly globalized world. By assessing the opportunities for residents to have a stronger voice in urban development, the thesis explores various perspectives that illuminate a previously under-described phenomenon, in an attempt to democratize participation in urban planning in a world that never stands still. The trend indicates that social considerations are being weighed less in conflicting interests, and that many places are planned to be attractive in an international competition. Recent place development seems to plan for culture, where this thesis explores how we can plan with culture

Norwegian Non-EU ETS-firms’ participation in Voluntary Carbon Markets and Alignment with national emissions reduction targets

Corporate actors within non-EU ETS sectors will likely play a significant role in reaching Norway’s target of reducing greenhouse gas emissions by at least 55% by 2030 compared to emissions levels in 1990, as a crucial part of reaching the national targets hinges on significant emissions reduction within these sectors. However, the systems surrounding these firms’ practices and determinants on emissions reduction and removal measures such as the purchase of voluntary carbon credits [VCCs] from voluntary carbon markets [VCMs] appears misaligned with both the emissions reduction targets set on the national level and the non-EU ETS sector-level. This thesis aims to understand the extent and determinants of Norwegian non-EU ETS sector actors’ participation in VCM through the form of VCC purchases and attempts to assess and address the need for system adaptations ensuring alignment of these practices with reaching national emissions reduction targets by 2030. Using a mixed-methods approach through an online questionnaire and semi-structured interviews with respectively 74 and six (6) respondents from firms in non-EU ETS sectors, the following three research questions were addressed: 1. How and to what extent do firms within Norwegian non-EU ETS sectors participate in the purchase of voluntary carbon credits?; 2. Which determinants influence the voluntary carbon credit practices of firms within Norwegian non-EU ETS sectors?; and 3. Which system adaptations might facilitate alignment between practices of Norwegian firms in non-EU ETS sectors purchasing or hypothetically purchasing VCCs, and Norway’s target of reducing national emissions by at least 55% of 1990-levels by 2030? Very low levels of VCM participation were identified among the studied firms, with only two firms reporting to currently purchase VCCs. Meanwhile, a number of firms reported hypothetically considering purchasing VCCs in the future. The purchasing and hypothetically purchasing firms’ type of VCM participation was mostly characteristic of inclination towards VCCs from carbon capture and storage [CCS] projects for the sake of climate financing or compensating for remaining emissions, with some reference to forest and land projects for carbon removal, and climate reduction projects in developing countries. The firms exhibit a clear tendency of prioritising reducing their own emissions before hypothetically purchasing VCCs, and display a clear preference for credible, measurable, and sector-relevant measures. In analysing determinants of current and hypothetical VCM participation through a thematic analysis, four main themes of determining factors were identified, namely 1. timing and priority of actions, 2. firms’ conditions for financial stability and profitability, 3. firms’ incentives and motivations in assessment of VCM participation, and 4. firms’ knowledge and preferences regarding corporate social responsibility [CSR], VCMs and VCCs. The firms current and hypothetical VCM participation display a clear tendency to be dominated by strategic considerations of upholding stakeholder accountability and legitimacy for financial survival, with discussable elements of altruism in choices not to engage in VCMs since they do not want to buy their way out of the responsibility of reducing their own emissions. Furthermore, they exhibit clear tendencies of dependence on customer demand and industry peers in adapting to altered conditions for competition and a lack of consensus on how to meet emissions reduction demands. Proposed system adaptations for increased alignment between non-EU ETS sector firms’ currently purchasing or considering purchasing VCCs and Norway’s emissions reduction targets include strengthening the role of civil society in forming sector-relevant policy and regulation in line with national circumstances, accelerated investment in emissions-reducing infrastructure, and capacity-building and collaboration across bodies of government, industry, academia and civil society.Corporate actors within non-EU ETS sectors will likely play a significant role in reaching Norway’s target of reducing greenhouse gas emissions by at least 55% by 2030 compared to emissions levels in 1990, as a crucial part of reaching the national targets hinges on significant emissions reduction within these sectors. However, the systems surrounding these firms’ practices and determinants on emissions reduction and removal measures such as the purchase of voluntary carbon credits [VCCs] from voluntary carbon markets [VCMs] appears misaligned with both the emissions reduction targets set on the national level and the non-EU ETS sector-level. This thesis aims to understand the extent and determinants of Norwegian non-EU ETS sector actors’ participation in VCM through the form of VCC purchases and attempts to assess and address the need for system adaptations ensuring alignment of these practices with reaching national emissions reduction targets by 2030. Using a mixed-methods approach through an online questionnaire and semi-structured interviews with respectively 74 and six (6) respondents from firms in non-EU ETS sectors, the following three research questions were addressed: 1. How and to what extent do firms within Norwegian non-EU ETS sectors participate in the purchase of voluntary carbon credits?; 2. Which determinants influence the voluntary carbon credit practices of firms within Norwegian non-EU ETS sectors?; and 3. Which system adaptations might facilitate alignment between practices of Norwegian firms in non-EU ETS sectors purchasing or hypothetically purchasing VCCs, and Norway’s target of reducing national emissions by at least 55% of 1990-levels by 2030? Very low levels of VCM participation were identified among the studied firms, with only two firms reporting to currently purchase VCCs. Meanwhile, a number of firms reported hypothetically considering purchasing VCCs in the future. The purchasing and hypothetically purchasing firms’ type of VCM participation was mostly characteristic of inclination towards VCCs from carbon capture and storage [CCS] projects for the sake of climate financing or compensating for remaining emissions, with some reference to forest and land projects for carbon removal, and climate reduction projects in developing countries. The firms exhibit a clear tendency of prioritising reducing their own emissions before hypothetically purchasing VCCs, and display a clear preference for credible, measurable, and sector-relevant measures. In analysing determinants of current and hypothetical VCM participation through a thematic analysis, four main themes of determining factors were identified, namely 1. timing and priority of actions, 2. firms’ conditions for financial stability and profitability, 3. firms’ incentives and motivations in assessment of VCM participation, and 4. firms’ knowledge and preferences regarding corporate social responsibility [CSR], VCMs and VCCs. The firms current and hypothetical VCM participation display a clear tendency to be dominated by strategic considerations of upholding stakeholder accountability and legitimacy for financial survival, with discussable elements of altruism in choices not to engage in VCMs since they do not want to buy their way out of the responsibility of reducing their own emissions. Furthermore, they exhibit clear tendencies of dependence on customer demand and industry peers in adapting to altered conditions for competition and a lack of consensus on how to meet emissions reduction demands. Proposed system adaptations for increased alignment between non-EU ETS sector firms’ currently purchasing or considering purchasing VCCs and Norway’s emissions reduction targets include strengthening the role of civil society in forming sector-relevant policy and regulation in line with national circumstances, accelerated investment in emissions-reducing infrastructure, and capacity-building and collaboration across bodies of government, industry, academia and civil society

Reconstruction and analysis of tissue-specific models of Atlantic salmon metabolism

The set of all biochemical reactions taking place in a living organism, converting nutrients to energy and growth, is referred to as metabolism. Metabolism is highly interconnected, forming metabolic pathways that can be mathematically formulated as graphs, with nodes (metabolites) connected by edges (reactions). By integrating information from sequenced and annotated genomes, a metabolic network may be extended to a genome-scale model (GEM), computationally representing all known metabolic information of the organism, as well as including all associated genomic attributes. GEMs constitute a predictive framework for simulating and quantifying the flow of biochemical compounds, referred to as metabolic fluxes, by formulating mechanistic genotype-phenotype relationships. Such tools facilitate research where a thorough understanding of metabolic processes is of interest. An example is the aquaculture industry, where GEMs simulate the effect of different feed compositions on the fish. However, not all metabolic pathways are active under all cellular states, making GEMs superfluous. In this study, context-specific metabolic models are extracted from an Atlantic salmon GEM using an experimental transcriptomic data set. Through a novel approach, these models are subsequently combined and generalized to constitute tissue-specific reconstructions of the Atlantic salmon gut, liver, and muscle. The tissue-specific metabolic models agree better with the expression data than the GEM, corroborating the notion that such models better capture the metabolic state of biological systems. The reconstructions are analyzed by utilizing constraint-based modeling (CBM), revealing key characteristics of metabolism in the three tissues. More specifically, the variation in possible flux states is investigated, revealing the metabolic scope and range of the three tissues. Furthermore, the study challenges the very definition of tissue-specific metabolic activity by investigating the agreement between model- and data-driven interpretations of the term. The results indicate that the agreement between the two definitions is low, supporting the utilization of approaches that consider biological constraints when analyzing metabolism. The findings of this study contribute to the current knowledge in Atlantic salmon systems biology research and will be beneficial for tissue-level simulation studies of the Atlantic salmon metabolism

Temporære tiltak som strategisk verktøy i byutviklingen av Hovinbyen

Hovinbyen er utpekt i Kommuneplanen “Oslo mot 2030” og i utkastet til planbeskrivelsen av ny arealdel i kommuneplanen “Oslo mot 2040” som et av de viktigste satsningsområdene i Oslo. Strategisk plan for Hovinbyen oppstiller tre mål som innebærer 1) en fremtidsrettet og klimasmart byutvidelse med et 2) mangfold av attraktive byområder som 3) integreres med hverandre og resten av Oslo. For å nå disse målene, i et femtiårsperspektiv, er det behov for en aktiv kommune og private aktører som tar i bruk diverse virkemidler. Strategisk plan for Hovinbyen trekker i denne sammenheng frem temporære tiltak som et strategisk verktøy for å fremme byutvikling, ved å øke oppmerksomheten mot et område og på den måten bidra til områdemodning. I denne studien ser vi på hvordan temporære tiltak kan brukes som et strategisk verktøy i byutviklingen av Hovinbyen. For å besvare denne problemstillingen har vi lagt et teoretisk grunnlag, der vi har sett nærmere på strategisk planlegging og temporære tiltak. Videre benyttet vi oss av kvalitativ metode. Den kvalitative datainnsamlingen bestod av seks semistrukturerte intervjuer, samt en dokumentstudie av strategisk plan for Hovinbyen. Den teoretiske og empiriske kunnskapen har gitt oss god innsikt og erfaringer for å besvare oppgavens problemstilling. Studien viser ulike tilnærminger til bruken av temporære tiltak, samt mulighetene og utfordringene knyttet til slike tiltak. Temporære tiltak kan ha varierte funksjoner, både som midlertidige løsninger og som et strategisk element i lengre byutviklingsprosjekter. Strategisk bruk av temporære tiltak innebærer å skape et fundament for fremtidig utvikling som fremmer områdemodning og bygger identitet i et område. Slik kan temporære tiltak bidra til sosiale, økonomiske, kulturelle og fysiske funksjoner i byutviklingen. Likevel viser funnene at både offentlige og private sektorer mangler nødvendige ressurser, kompetanse og organisatorisk struktur for å utvikle og forvalte temporære tiltak som et strategisk verktøy. Selv om strategisk plan for Hovinbyen har potensial til å være et strategisk rammeverk for bruken av temporære tiltak, kreves det organisatoriske tilpasninger og en tydeligere forpliktelse fra både offentlige og private aktører for å fremme strategisk bruk av temporære tiltak.Hovinbyen has been designated in the municipal plan "Oslo mot 2030" and in the draft of the plan description of the new area part in the municipal plan "Oslo mot 2040" as one of the most important focus areas in Oslo. “Strategisk plan for Hovinbyen” sets out three goals, which involve 1) a forward-looking and climate-smart urban expansion with a 2) diversity of attractive urban areas that are 3) integrated with each other and the rest of Oslo. To achieve these goals, over a fifty-year perspective, there is a need for an active municipality and private actors who utilize various tools. In this context, “strategisk plan for Hovinbyen” highlights temporary use as a strategic tool to promote urban development by increasing attention to an area and thereby contributing to area maturation. In this study, we look at how temporary use can be used as a strategic tool in the urban development of Hovinbyen. To address this issue, we have established a theoretical foundation, where we have looked closer at strategic planning and temporary use. Furthermore, we used a qualitative method. The qualitative data collection consisted of six semi-structured interviews and a document study of “strategisk plan for Hovinbyen”. The theoretical and empirical knowledge has given us good insights and experiences to answer the research question. The study shows various approaches to the use of temporary use, as well as the opportunities and challenges associated with such measures. Temporary use can have varied functions, both as temporary solutions and as a strategic element in longer urban development projects. Strategic utilization of temporary use involves creating a foundation for future development, which promotes area maturation and builds identity in an area. In this way, temporary use can contribute to social, economic, cultural, and physical functions in urban development. However, the findings indicate that both public and private sectors lack the necessary resources, expertise, and organizational structure to develop and manage temporary use as a strategic tool. Although “strategisk plan for Hovinbyen” has the potential to be a strategic framework for the use of temporary use, organizational adjustments and a clearer commitment from both public and private actors are required to promote strategic utilization of temporary use

Resharing spaces, services and mobility: Developing a reshareability index for sustainable planning in Oslo

Recent studies on sharing cities and sharing economies have focused on what can be (or is being) shared, such as public spaces, food, mobility, ideas, knowledge, governance strategies, as well as community facilities, such as places for working, education and welfare. Following this emerging trend of sharing, this paper explores the novel approach of resharing, that aims to support, amongst other things, the integration of mobility sharing and different forms of space sharing in residential, office and commercial buildings. Firstly, the study presents a novel theoretical and conceptual approach to (re)sharing, and secondly, it reports on an empirical analysis conducted in the urban district of Hovinbyen in Oslo, using the sub-districts of Løren and Økern as the two main cases. The study analyzes existing preconditions for reshareability and suggests an index of reshareability to guide future developments. Løren is, to some extent, better equipped than Økern to apply the resharing approach, and can thus become a place for further experimentation with local communities and stakeholders. The study contributes to understanding and assessing the reshared qualities and characteristics of city neighborhoods, which can provide a foundation for developing planning strategies to make local neighborhoods more ‘sharing oriented’ or ‘reshareable’.Resharing spaces, services and mobility: Developing a reshareability index for sustainable planning in OslopublishedVersio

Risks posed by managed honey bees (Apis mellifera) to wild pollinators in Norway

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The importance of thermal stratification and oxygen conditions for internal cycling of nitrogen and release of phosphorus in Lake Årungen.

Eutrophication together with its subsequent effects, increased levels of phytoplankton, algae, decreased water transparency and oxygen depletion poses a significant threat to our limnic systems. Cultural eutrophication, in particular, significantly shortens the lifespan of freshwater bodies compared to natural processes. Lake Årungen, a dimictic lake, undergoes seasonal mixing, impacting its oxygen levels and nutrient distribution. During stratification, the lake experiences anoxic conditions in the hypolimnion, affecting the nitrogen and phosphorus cycles. The presence of nitrate in the hypolimnion can buffer against phosphorus release from sediments, mitigating eutrophication. The degree of mixing in Lake Årungen, influenced by wind and weather conditions, is crucial for maintaining water quality. Increased air temperatures due to climate change are contributing to the earlier onset and greater stability of thermal stratification in lakes such as Lake Årungen. This prolonged stratification period can lead to extended anoxic conditions in the hypolimnion and increases chances of internal phosphorus loading. Effective management of nutrient inputs, particularly from agriculture, is essential to counteract eutrophication and preserve freshwater ecosystems. Increased thermal stratification stability from increased air temperatures early in the season reduces oxygen distribution, increasing anoxia duration and necessitating higher nitrate levels to prevent reducing conditions. Comparative data from previous years (2017, 2013, and 2009) indicated that sufficient nitrate levels are critical in buffering phosphorus release from sediments. In 2023, nitrate levels at the onset of anoxia were 2.6 mg/l, maintaining a high redox potential and preventing significant internal phosphorus loading. In contrast, lower nitrate levels in earlier years led to substantial phosphorus release. Threshold levels for nitrate concentration, crucial in preventing internal phosphorus loading, are influenced by various biogeochemical and environmental factors, including sediment composition, pH, and microbial activity. Effective management strategies should focus on reducing external nitrate inputs and maintaining higher nitrate levels to mitigate the impacts of prolonged thermal stratification and prevent eutrophication in Lake Årungen

“DREAMS” Drone Research and Affordable Mapping Solutions: Integrating DJI Tello with ORB-SLAM3

The expanding world of drone technology has led to many exciting possibilities in various fields,such as surveillance and monitoring. Equipping drones with different sensors, depending on the use case makes drones invaluable in many applications, especially for environment mapping. Many of these sensors, or the drones equipped with them are costly and high maintenance, which opens up for the creation and implementation of cost-effective and efficient mapping solutions, making it available for a much broader audience, also those that do not have big budgets. By focusing on building and implementing a low-cost mapping solution, this dissertation demonstrates how SLAM technology can be integrated with low-price drones while achieving accurate maps across various scenarios and environments. Through extensive research, a solution to this challenge presented itself with the DJI Tello drone and the ORB-SLAM3 package. Despite its modest specifications, the Tello drone’s user-friendly and affordable nature makes it an ideal candidate for such a system, and with its monocular camera, proved to be highly compatible with the ORB-SLAM3 algorithm. The open-source nature of ORB-SLAM enables customization, therefore making it applicable in a variety of scenarios. The option to change the number of features to be extracted and change the thresholds, allows the system to perform well even in low-contrast areas. During this project, the system has been tested in various scenarios and environments and as a result, had its limitations and challenges showcased such as limited flight time or poor performance in strong winds. Regardless of its limitations, the system proves its ability to create accurate maps and shows how much potential such a system holds. The result was a package solution for performing ORB-SLAM on the DJI Tello drone, and the insights gained from research conducted in this thesis show that it is entirely possible to achieve high-quality mapping even with a limited budget. In conclusion, this project introduces the development of a drone-based mapping system capable of creating highly detailed maps with just a drone equipped with a 720p pinhole camera. It lays the groundwork for future research, continually improving and enhancing the field of low-cost drone-based mapping systems