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Vibration Performance of Joisted Timber Floors Based on Eurocode 5 Considering Different Furniture Arrangements and Floor Toppings
Get PDFBruken av tre som konstruksjonsmateriale har økt betydelig de siste årene, drevet av faktorer som økt miljøbevissthet og materialets høye stivhet i forhold til egenvekt. Trestrukturer har imidlertid også noen utfordringer, spesielt knyttet til vibrasjoner på grunn av lav egenmasse.
Dette har ført til økt interesse for forskning på vibrasjoner i tregulv. De fleste studier har fokusert på gulv uten å ta hensyn til effekten av statiske nyttelaster som møbler. Kun et fåtall studier har undersøkt dette aspektet, og påvirkningen møbler har på vibrasjoner er derfor ikke blitt grundig undersøkt. Denne masteroppgaven undersøker hvordan møbler påvirker den dynamiske oppførselen til et bjelkelagsgulv av tre gjennom eksperimentelle tester og numerisk modellering.
Det ble utført eksperimentelle tester for å identifisere gulvets modale parametere, som inkluderer egenfrekvenser, modusform og demping. I tillegg ble kvadratisk gjennomsnitt av akselerasjon beregnet fra responser i tidsdomene indusert av gange. Testene ble utført på et gulv med ulike lagkonfigurasjoner med økende masse. Konfigurasjonene varierte fra å ha ingen ekstra lag, til å inkludere et lag med avrettingsmasse og gulvbelegg oppå sponplaten. Ulike møbleringsoppsett ble også undersøkt, hvor både den generelle effekten av å tilføre møbler og virkningen av ulike plasseringer ble vurdert. Som et supplement til de eksperimentelle testene ble det utviklet en digital modell av gulvet i SAP2000, for å sammenligne numeriske og eksperimentelle resultater.
Et sentralt funn er at møbler har en tydelig effekt på modale parametere og dynamiske responser, ved å redusere grunnfrekvensen, øke dempingen og reduserte akselerasjonsverdier, spesielt når møblene plasseres nær midten av gulvet. For lette tregulv bør møblering tas med i beregninger av vibrasjoner, da disse er mer følsomme for plasseringen av nyttelast. For tyngre gulv har derimot møblers plassering mindre innvirkning, og slike laster kan derfor behandles som flatelaster ved beregning av RMS-akselerasjon i henhold til Eurokode 5.
Et annet viktig funn i denne studien er sammenhengen mellom formen for grunnmodusen og RMS-akselerasjon, hvor de høyeste verdiene for RMS-akselerasjon ofte oppstår der amplituden i grunnmodusformen er størst.The use of timber as a structural material has increased significantly in recent years, driven by factors such as growing environmental awareness and its high stiffness-to-mass ratio. However, timber structures also present some challenges, particularly with vibrations due to their low mass.
This has led to growing research interest in the vibration behaviour of timber floors. Most studies have focused on bare floors, without considering the effect of static live loads such as furniture. Only a small number have addressed this aspect, and the influence of furniture on vibration response has therefore not been thoroughly investigated. This thesis investigates the influence of furniture on the dynamic behaviour of a joisted timber floor through experimental testing and numerical modelling.
Experimental tests were conducted to identify the modal parameters of the floor, including natural frequencies, mode shapes and damping. Additionally, root mean square acceleration was calculated from time-history responses induced by walking excitation. Tests were carried out on a floor with various layer configurations of increasing mass. The configurations ranged from having no additional layer, to adding a layer of screed and floor covering on top of the particle board. Different furniture arrangements were also investigated, evaluating both the general effect of adding furniture and the influence of different arrangements. Complementing the experimental tests, a finite element model of the floor was developed in SAP2000 to compare numerical and experimental results.
One key finding is that furniture has a clear effect on modal parameters and dynamic responses, lowering the fundamental frequency, increasing damping, and reducing acceleration responses, particularly when placed near the centre of the floor. For lightweight floors, furniture arrangements should be considered in vibration calculations, due to greater sensitivity to load positioning. In contrast, for heavier floors the position of live loads show less impact and can therefore be treated as surface loads when calculating RMS acceleration using Eurocode 5 formulas.
Another important finding from this study is the correlation between fundamental mode shape and RMS acceleration, where the maximum RMS acceleration values tend to occur at locations where the fundamental mode shape amplitude is highest
Eligibility propagation with speech recognition
Get PDFThis master thesis presents a preliminary exploration of using Spiking Neural Networks (RSNN) with the learning algorithm Eligibility Propagation (e-prop) for speech recognition. While Back Propagation Through Time has shown that RSNN can learn, it is not biologically plausible. E-prop uses eligibility traces with a learning signal to get performance similar to Back Propagation Through Time and functions more similarly to the brain.
This enables SRNN with e-prop as a decoder for speech recognition, where it should predict the correct classes based on the input. The input was a spoken dataset similar to MNIST, encoded with the Conformer model. Two experimental setups were made to use an SRNN as a decoder. The first made the SRNN correctly label every timestep of a sequence into a class. The second task was for the network to process a sequence with one word and then predict the correct class.
The results from the first setup show that SRNN with e-prop can be trained on an input sequence and can give high-scoring predictions if the sequence does not change. The second setup shows that the networks can predict the correct classes for a simple binary test. It has also been demonstrated that bigger networks trained with more samples perform better. This is also shown when the network is given three classes to predict.
While it is clear that SRNN with e-prop could be used for speech recognition, much work remains for it to become a competing model. This thesis shows some early findings and gives reasons for further investigation into optimising the task setup for better performance
Norway and Russia in the Arctic: From cooperative interdependence to weaponized interdependence in the Barents Sea.
Get PDFFor centuries, the Arctic – often referred to as the High North – has played a crucial role in Norway´s development and strategic position. Its rich fishing grounds have sustained coastal communities, while oil, gas, and mineral resources have significantly contributed to the economy. The Arctic is part of Norway´s identity, reflected in its strong connection to the sea and nature. Today, the region also constitutes Norway´s primary strategic arena. As climate change accelerates the melting of ice, new shipping lanes and widened access to Arctic resources are increasing interest in the region. Though the Arctic has been relatively stable, with some scientific cooperation persisting even during the Cold War, tensions have recently risen as actors compete over access. Most notably, Russia has intensified its presence and activity, with material implications for Norwegian security and economic interests. While the region has long been militarized, Russia´s invasion of Ukraine in 2022 has fundamentally altered Norway´s perception of these military resources – that is, from being largely seen as defensive to having clear-and-present offensive potential.
This thesis explores how Norway and Norwegian private maritime actors are being affected by and responding to Russia´s evolving threat potential in the Arctic, specifically in the Barents Sea. This threat is shaped not only by Russia´s regional activity but also its increasing global aggression. The study outlines how Norway is adjusting to protect its maritime interests amid deteriorating relations with Russia, despite historically high – but variable – levels of interdependence. From the 1970s until 2014, bilateral cooperation in the Barents Sea and broader Arctic encompassed fisheries management, oil and gas extraction, and environmental protection. These ties built mutual dependency, contributing to shared stability and benefits. However, as this study will argue, this phase of cooperative interdependence has come to an end, interrupted by two significant shocks: first, Russia´s annexation of Crimea in 2014; and second, its full-scale invasion of Ukraine in 2022. In parallel, as this thesis will show, Russia is weaponizing its interdependence with Norway, ramping up its military activities in the Arctic, eroding trust and forcing Norway and its maritime industry to adapt to a new risk reality in its strategic backyard. It is vital to note that the increasing weaponization of interdependence has not erased all forms of cooperation, creating an ambiguous picture where enhanced militarization and rising risk of conflict are layered over areas of mutual interest where functional collaboration remains somewhat intact
Understanding local responses to green hydrogen in Norway : symbolic meanings of place and technology in Arendal and Bremanger
Get PDFThis thesis explores how local communities in Arendal and Bremanger, Norway, respond to green hydrogen projects, focusing on the symbolic meanings of place and technology. Using a qualitative approach with secondary sources, it finds that local meanings shape residents' reactions—seeing the technology as either a disruption or threat. These responses reflect broader concerns about ownership, control, and preserving local identity, emphasizing the need for inclusive decision-making in green energy transitions.B-D
Climate Shocks, Fertilizer Use, and Cropping Intensity Among Smallholder Irrigation Farmers in Chikwawa District, Malawi
No full textThe objective of the study is to examine how climate shocks influence input use intensity and land utilization decisions among smallholder irrigation farmers in Chikwawa District, Malawi. Specifically, the study assess the effects of excessive rainfall and prolonged dry spells on fertilizer use and cropping intensity, while also assessing the role of input subsidies and water access in shaping these outcomes
Krevende og givende
Get PDFBakgrunn: Rundt 400 000 personer i Norge er i dag pårørende til noen med demens. Denne gruppen har behov for individuell oppfølging grunnet de mentale og fysiske belastningene som ofte følger med pårørenderollen. Oppfølgingen ivaretas ofte av den kommunale demenskoordinatoren.
Formål: Det finnes få kvalitative studier som belyser demenskoordinatorers erfaringer med pårørende til hjemmeboende personer med demens. Formålet med denne masteroppgaven er å få dypere innsikt i demenskoordinatorenes erfaringer.
Metode: Studien benytter en kvalitativ tilnærming med individuelle semistrukturerte intervjuer av fem demenskoordinatorer. Analysemetoden som er benyttet er Malteruds (2021) systematiske tekstkondensering (STC), en pragmatisk og tematisk metode for tverrgående analyse av kvalitative data. Resultatene er drøftet i lys av teoretiske perspektiver, tidligere forskning og relevant litteratur.
Resultater: Analyseprosessen resulterte i fem temaer:
• Det viktige første møtet – etablere relasjon og kartlegge behov
• Alle pårørende er forskjellige – individuell tilrettelegging
• Hva er viktig og når er det riktig – iverksetting av tiltak
• Sammen er pårørende mindre alene – støtte gjennom møteplasser
• Der det er liv, er det håp – fremme pårørendes ressurser
Oppsummering: Demenskoordinatorenes hovedfokus er å ivareta personen med demens. Samtidig fremhever de at dersom personen med demens skal kunne bo trygt hjemme over tid, er de helt avhengig av et tett samarbeid med personens pårørende. Funnene viser at relasjonsbygging, individuell tilpasning, kontinuerlig støtte, veiledning og strukturert opplæring er sentrale komponenter i pårørendearbeidet. Deltakerne uttrykker bekymring for en økende pårørendegruppe i takt med en aldrende befolkning, og peker på behovet for økte ressurser for å sikre et bærekraftig tilbud fremover.Background: Approximately 400,000 people in Norway are currently caregivers for someone living with dementia. This group often requires individualized follow-up due to the mental and physical strain associated with the caregiving role. This follow-up is frequently provided by municipal case managers.
Aim: There is a lack of qualitative studies that explore case managers' experiences with caregivers of home-dwelling individuals with dementia. The aim of this master’s thesis is to gain deeper insight into the experiences of case managers.
Method: A qualitative research design was used, involving individual semi-structured interviews with five case managers. The data was analyzed using Malterud’s (2021) Systematic Text Condensation (STC), a pragmatic and thematic method for cross-case analysis of qualitative data. The results were discussed in relation to theoretical perspectives, previous research, and relevant literature.
Results: The analysis process resulted in five themes:
• The importance of the first meeting – establishing relationships and identifying needs
• Every caregiver is different – individualized support
• What is important and when is it appropriate – implementation of measures
• Together, caregivers feel less alone – facilitating support through peer contact
• Where there is life, there is hope – promoting caregivers' strengths
Conclusion: The primary focus of case managers is to support the person with dementia. At the same time, they emphasize that if the person with dementia is to remain safely at home over time, close collaboration with caregivers is essential. The findings show that relationship-building, individual adaptation, continuous support, guidance, and structured training are key components of their work with caregivers. The participants express concern about a growing number of caregivers in line with an aging population and highlight the need for increased resources to ensure a sustainable service in the future
Pepper mild mottle virus as a potential indicator of occupational exposure to airborne viruses in wastewater treatment plants
Get PDFWastewater is a known carrier for human pathogenic viruses, with seasonal variations in concentrations, and wastewater treatment plant (WWTP) workers are a potentially overlooked occupational group regarding exposure to secondary aerosolized viruses. Exposure assessment of airborne pathogens is complicated by a lack of universal markers of viruses, no standardized sampling protocol, and challenges in detecting extremely low-abundant targets. In this study, we evaluate the risk of workers’ exposure to 4 pathogens, Adenovirus, Norovirus GI and GII, and Influenza A and the Pepper mild mottle virus (PMMoV) as an indicator for aerosolized viruses from wastewater, in 3 WWTPs in the Oslo region, Norway. We collected personal and stationary air samples in summer and winter and used digital droplet PCR (ddPCR) to enable the detection of low-abundant targets. Pathogenic viruses were detected in 22% of all samples, with similar detection rates in personal and stationary samples, with a maximum concentration of 762 genome copies/m3 air. PMMoV was detected in 69% of all samples, with concentrations ranging from 28 to 9703 genome copies/m3 air. The pathogens and PMMoV were most frequently detected at the grids, biological cleansing, sedimentation basins, and sludge treatment/de-watering stations, and were associated with tasks such as flushing, cleaning, and maintenance of the same workstations. Overall, the concentration of pathogens and PMMoV in the air was low, but there is a potential for high point exposure which may pose a risk to workers’ health and is increased by the nature of the workers’ tasks. PMMoV may be a promising tool for assessing the overall potential for viruses with human waste origin aerosolized from sewage. To strengthen this indicator-based approach to occupational exposure assessment, we recommend validating PMMoV along with other potential indicators. Validation should include evaluating the correlation between these indicators and pathogens in both wastewater and bioaerosols.publishedVersio
Tracking Diel Activity and Foraging Patterns of Breeding Glaucous Gull Larus hyperboreus on Bjørnøya
Get PDFKnowledge on diel activity, habitat use, and foraging patterns are fundamental to understanding a species’ ecological role. Especially for species in decline such ecological knowledge is key when managing populations. Glaucous gulls Larus hyperboreus at Bjørnøya have been exposed to high levels of persistent organic pollutants for more than 50 years, resulting in dramatic effects on the population. Though this is likely a result of diet and role as apex predator, detailed insight into diet and, especially, foraging patterns remains limited. In an attempt to close this knowledge gap, 12 breeding glaucous gulls were monitored with nest cameras and GPS at Bjørnøya in the Barents Sea in 2024. By combining data on food provisioning from nest cameras with fine-scale GPS tracking we aimed to document both temporal and spatial trends in foraging behaviour. The glaucous gulls did not display any clear diurnal activity patterns in food provisioning, with foraging occurring continuously throughout the polar day. GPS data revealed exclusive use of the coastal habitat, with minimal behavioural plasticity in terms of both general area use and foraging patterns. Social aggregation sites were frequently used. However, nest attendance was prioritized, with approximately 80% of the time spent at the nest. Prey was sourced locally, averaging only 87 meters way from the nest, and no trips exceeded 5.5 km from the nest site. Guillemot chicks and capelin were the most common identified preys, with the latter most likely being obtained through kleptoparasitism. The results found foraging to occur continuously throughout the polar day and predominantly near the nest site, aligning with the initial hypotheses and predictions. Through small home ranges, breeding glaucous gulls at Bjørnøya exhibit a high degree of site fidelity. The results provide a valuable foundation for knowledge-based management
Modellering og beregning av miljøforårsaket mismatchtap for solcellemoduler ved hjelp av strålesporingssimuleringer
Get PDFMed økende fokus på fornybare energikilder og utnyttelse av disse er solcelleindu-
strien i stadig utvikling. Tosidige solcellemoduler som utnytter reflektert sollys på
modulenes bakside blir i større grad foretrukket over ensidige moduler. For å kunne
dra mer nytte av den reflekterte solinnstrålingen er det ønskelig med programmer
som effektivt kan modellere og simulere ytelse i designfasen av anlegget. På denne
måten kan en avdekke fallgruver som kan oppstå som følge av eksempelvis skygging
fra nærliggende objekter, og en kan på den måten redusere tapene i anlegget. Blant
tapene som oppstår i et solcelleanlegg er det som kalles mismatchtap. Det vil si et
effekttap som oppstår når solceller eller moduler i et anlegg ikke opererer under iden-
tiske forhold. Tapet uttrykkes som forskjellen mellom den faktiske effekten og den
effekten som kunne vært oppnådd dersom alle celler eller moduler opererte optimalt
under like forhold. Dette innebærer at moduler med høyt mismatchtap potensielt
kunne levert høyere effekt enn de faktisk gjør.
I denne oppgaven har det blitt modellert et vertikalt solcelleanlegg for å analysere
mismatchtapene som oppstår som følge av miljømessige påvirkninger. Dette er gjort
ved hjelp av programmet Rhinoceros 3D med strålesporingssimuleringer av innstrålt
sollys. Basert på dette er det beregnet mismatchtap for anlegget som helhet, for rader
av moduler og for enkeltmoduler. Det er vist at rammeverk, modulenes høyde over
bakken og nærliggende objekter påvirker innstrålingen og bidrar til å øke mismatch-
tapet. Det er samtidig sett at en modul med høyt mismatchtap kan levere høyere
effekt enn en modul med lavt mismatchtap siden effekten ut avhenger av totalinn-
strålingen. Ulike strengkonfigurasjoner for hver modul er testet for og det er sett at
å bruke 6 strenger i stedet for 3 som regel reduserer mismatchtapet.
Ved hjelp av programmet er det testet for ulike scenarioer med tillegging av
nærobjekter og fjerning av rammeverk for å teste fleksibiliteten. Her er det sett
at programmet er følsomt og klarer å ta høyde for små endringer i terrenget som
er med på å påvirke tapene. Ved bruk av en referansemetode ble det vist at ved
tillegging av fjernobjekter økte tapene med 0,4 %, mens ved fjerning av rammeverk
sank tapene med 0,75 %. Ved tillegging av en boks som representasjon for plantevekst
ble økningen i tap mer betydelig på 17,42 % og 6,83 % for henholdsvis 3 og 6 strenger
ved bruk av referansemetoden. For øvrige metoder som er utviklet så en de samme
tendensene som underbygger fleksibiliteten.
Dermed er det sett i oppgaven at modellen som er laget gir et godt grunnlag for
modellering og beregning av mismatchtap som så kan brukes i andre simuleringspro-
grammer for videre analyse.With the increasing focus on renewable energy sources and their utilization, the solar
cell industry is continuously evolving. Bifacial solar modules, which utilize reflected
sunlight on the rear side of the modules, are increasingly favored over monofacial
ones. To better take advantage of the reflected solar irradiance, it is desirable to
have software capable of effectively modeling and simulating performance during the
design phase of a system. This allows potential pitfalls, such as shading from nearby
objects, to be identified and thus reduce losses in the system. Among the losses
occurring in a solar power system are what is referred to as mismatch losses. These
are power losses that arise when solar cells or modules in a system do not operate
under identical conditions. The loss is expressed as the difference between the actual
power output and the power that could have been achieved if all cells or modules
operated optimally under the same conditions. This means that modules with high
mismatch losses could potentially have delivered more power than they actually do.
In this thesis, a vertical solar installation has been modeled to analyze the mis-
match losses resulting from environmental influences. This has been done using Rhi-
noceros 3D with ray tracing simulations of incident sunlight. Based on these simula-
tions, mismatch losses have been calculated for the entire system, for rows of modules,
and for individual modules. It has been shown that the framework, the height of the
modules above ground, and nearby objects influence the irradiance and contribute
to increased mismatch losses. At the same time, it has been observed that a mo-
dule with high mismatch loss can deliver higher power output than a module with
low mismatch loss, since the output depends on the total irradiance. Different string
configurations for each module were tested, and it was found that using 6 strings
instead of 3 generally reduces the mismatch losses.
Using the program, various scenarios were tested by adding nearby objects and
removing parts of the framework to assess its flexibility. It was found that the program
is sensitive and capable of accounting for small changes in the terrain that affect the
losses. Using a reference method, it was shown that adding distant objects increased
losses by 0.4 %, while removing the framework reduced by 0,75 %. When a box
representing plant growth was added, the increase in losses became more significant
at 17.42 % and 6.83 % for 3 and 6 strings, respectively, using the reference method.
The other methods developed showed the same tendencies, further supporting the
model’s flexibility.
Thus, the thesis demonstrates that the developed model provides a solid founda-
tion for modeling and calculating mismatch losses, which can then be used in other
simulation software for further analysis
Kommunens bruk av planverktøy og juridiske virkemidler i møte med privat eiendomsutvikling – En casestudie av Sandvika sentrum øst
Get PDFDenne masteroppgaven undersøker hvordan Bærum kommune styrer utviklingen av Sandvika sentrum øst gjennom bruk av planverktøy og juridiske virkemidler, og hvordan disse styringsgrepene faktisk slår ut i gjennomføringen av et konkret byutviklingsprosjekt: Helgerudkvartalet. Med Helgerudkvartalet som casestudie analyseres det i hvilken grad styringsverktøyene er tilstrekkelige for å sikre at allmenne og offentlige interesser realiseres i møte med privat utbygging.
Studien er forankret i kvalitativ dokumentanalyse av blant annet områderegulering, VPOR og utbyggingsavtaler, og bygger på teori om urbane kvaliteter og byliv (Carmona et al., 2003; Gehl, 2010). Teoriene danner grunnlag for å vurdere hvordan kommunen oversetter sine planintensjoner til konkrete krav og rekkefølgebestemmelser – og om disse er tilstrekkelige for å sikre kvalitet og allmenne interesser gjennom hele utbyggingsprosessen.
Analysen viser at kommunen har utviklet et omfattende sett av virkemidler for å styre transformasjonen av Sandvika sentrum øst. Kombinasjonen av reguleringsplanens bestemmelser, rekkefølgekrav og økonomiske forpliktelser i utbyggingsavtaler gir kommunen et formelt handlingsrom og har stor betydning. Helgerudkvartalet fremstår som et prosjekt som i stor grad følger opp kommunens målsettinger om funksjonsmiks og levende byrom. Samtidig viser oppgaven at realiseringen av disse målene i praksis avhenger av utbyggerens prioriteringer og kommunens evne til aktiv forvaltning og tett oppfølging.
Funnene har relevans for andre kommuner i lignende transformasjonsprosesser, og spesielt relevant for videre utvikling av Sandvika. Det foreslås at prosjektet følges opp etter ferdigstillelse, for å kunne evaluere hvordan byrom, funksjoner og fysiske kvaliteter faktisk oppleves og brukes av innbyggerne over tid.This master’s thesis examines how Bærum Municipality governs the development of Sandvika sentrum east through the use of planning tools and legal instruments, and how these governance measures are reflected in the implementation of a concrete urban development project: Helgerudkvartalet. Using Helgerudkvartalet as a case study, the thesis analyses to what extent the municipality’s tools are sufficient to ensure that public interests are upheld in a privately led development process.
The study is based on a qualitative document analysis of planning documents, including the area zoning plan, the Guiding Plan for Public Space (VPOR), and the development agreement. The analysis is grounded in urban theory on public space and city life (Carmona et al., 2003; Gehl, 2010), which provides a framework for assessing how the municipality translates its planning ambitions into concrete requirements and sequencing conditions – and whether these are sufficient to safeguard quality and public value throughout the development process.
The analysis shows that the municipality has developed a comprehensive set of instruments to guide the transformation of Sandvika sentrum øst. The combination of zoning provisions, sequencing requirements, and financial obligations in development agreements provides formal authority and has considerable impact. Helgerudkvartalet appears to align with the municipality’s objectives for functional diversity and active public spaces. At the same time, the findings indicate that the actual realization of these goals depends heavily on the priorities of private developers and the municipality’s capacity for active management and close follow-up.
The findings are relevant for other municipalities undergoing similar transformation processes and are particularly important for the continued development of Sandvika. It is recommended that the project be evaluated after completion, in order to assess how public spaces, functions, and physical qualities are actually experienced and used by residents over time