Fakultet for naturvitenskap og teknologi: Nye registreringer
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The poset of Specht ideals for hyperoctahedral groups
(Journal article; Tidsskriftartikkel, 2023)Specht polynomials classically realize the irreducible representations of the symmetric group. The ideals defined by these polynomials provide a strong connection with the combinatorics of Young tableaux and have been intensively studied by several authors. We initiate similar investigations for the ideals defined by the Specht polynomials associated to the hyperoctahedral group <i>B<sub>n</sub></i>. ... -
The impact of safety factors on decision-making in maritime navigation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023)Approximately 85% of maritime accidents are accounted for by navigation accidents, caused by human errors such as mistakes in impropriate decision-making. Decision-making skills are the key to safe sailing. However, the assessment of decisionmaking based on objective measurements is rarely studied. This paper aims to assess the impact of safety factors on decision-making in maritime navigation. ... -
Linear slices of Hyperbolic polynomials and positivity of symmetric polynomial functions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-17)A real univariate polynomial of degree n is called hyperbolic if all of its n roots are on the real line. Such polynomials appear quite naturally in different applications, for example, in combinatorics and optimization. The focus of this article is on families of hyperbolic polynomials which are determined through k linear conditions on the coefficients. The coefficients corresponding to such a ... -
Approximate Bayesian Inference Based on Expected Evaluations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-01)Approximate Bayesian computing (ABC) and Bayesian Synthetic likelihood (BSL) are two popular families of methods to evaluate the posterior distribution when the likelihood function is not available or tractable. For existing variants of ABC and BSL, the focus is usually first put on the simulation algorithm, and after that the form of the resulting approximate posterior distribution comes as a ... -
Fishing Trawler Event Detection: An Important Step Towards Digitization of Sustainable Fishing
(Chapter; Bokkapittel, 2023-08-02)Detection of anomalies within data streams is an important task that is useful for different important societal challenges such as in traffic control and fraud detection. To be able to perform anomaly detection, unsupervised analysis of data is an important key factor, especially in domains where obtaining labelled data is difficult or where the anomalies that should be detected are often ... -
Mesospheric Dust - radar applications for detection and investigation
(Doctoral thesis; Doktorgradsavhandling, 2023-11-15)<p>Large amounts of meteoric particles ablate globally into the Earth’s atmosphere each day, and they interact with the atmosphere through several processes in the mesosphere and below. These processes include dust charging, where dust is expected to influence the charge balance in the D-region of the ionosphere. Consequently, the charged dust particles can influence the incoherent scatter that is ... -
Characterizing Håkon Mosby Mud Volcano (Barents Sea) cold seep systems by combining ROV-based acoustic data and underwater photogrammetry
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-31)Cold-seep systems have a unique geo-ecological significance in the deep-sea environment. They impact the variability of present-day submarine sedimentary environments, affecting the evolution of the landscape over time and creating a variety of submarine landforms, one of which is Mud Volcanoes (MVs). MVs are submarine landforms form due extrusion of mud, fluids, and gas, mainly methane, from deeper ... -
An Arctic natural oil seep investigated from space to the seafloor
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-19)Due to climate change, decreasing ice cover and increasing industrial activities, Arctic marine ecosystems are expected to face higher levels of anthropogenic stress. To sustain healthy and productive ocean ecosystems, it is imperative to build baseline data to assess future changes. Herein, a natural oil seep site offshore western Svalbard (Prins Karls Forland, PKF, 80–100 m water depth), discovered ... -
A Heterotic Kodaira--Spencer Theory at One-Loop
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-23)We consider a heterotic version of six-dimensional Kodaira-Spencer gravity derived from the heterotic superpotential. We compute the one-loop partition function and fnd it can be expressed as a product of holomorphic Ray-Singer torsions. We discuss its topological properties and potential gauge and gravitational anomalies. We show these anomalies can be cancelled using Green-Schwarz-like ... -
An Integrative Taxonomic Survey of Benthic Foraminiferal Species (Protista, Rhizaria) from the Eastern Clarion-Clipperton Zone
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-24)The abyssal Pacific Clarion Clipperton Zone (CCZ) hosts vast, commercially valuable seafloor deposits of polymetallic nodules. Foraminifera (testate protists) dominate benthic communities in this region. Here, we present a taxonomic survey, combining morphological and genetic data and focussing on mainly meiofauna-sized Foraminifera from the eastern CCZ. Sequences obtained from >100 specimens, the ... -
Barents-2.5km v2.0: an operational data-assimilative coupled ocean and sea ice ensemble prediction model for the Barents Sea and Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-22)An operational ocean and sea ice forecast model, Barents-2.5, is implemented for short-term forecasting at the coast off northern Norway, the Barents Sea, and the waters around Svalbard. Primary forecast parameters are sea ice concentration (SIC), sea surface temperature (SST), and ocean currents. The model also provides input data for drift modeling of pollutants, icebergs, and search-and-rescue ... -
Change in Climate Sensitivity and Its Dependence on the Lapse-Rate Feedback in 4 x CO2 Climate Model Experiments
(Journal article; Tidsskriftartikkel, 2022-04-19)Robust estimates of climate sensitivity are important for decision-making on mitigation of climate change. However, climate sensitivity and its governing processes are still subject to large uncertainty. Recently it has been established that climate sensitivity changes over time in numerical climate model experiments with abrupt quadrupling of the CO<sub>2</sub> concentration. Here we conduct an ... -
Kunnskapsoverføring i beredskapsorganisasjoner i Longyeabyen, Svalbard - En kvalitativ studie av forvaltningen av taus kunnskap i beredskapsorganisasjoner preget av høy turnover
(Master thesis; Mastergradsoppgave, 2023-07-13)Svalbard er et lite arktisk øysamfunn som betegnes som et rotasjonssamfunn. Høy turnover av ansatte i Longyearbyens beredskapsorganisasjoner har gjentatte ganger blitt fremhevet som en utfordring for erfarings- og kunnskapsoverføring (DSB, 2016), og for kontinuiteten i arbeidet med samfunnssikkerhet- og beredskap. Etter det fatale snøskredet i 2015 ble etablering av en systematikk som ivaretar ... -
Felles situasjonsforståelse og styring under kriser
(Master thesis; Mastergradsoppgave, 2023-06-30)Natt til 30.desember 2020 gikk det et kvikkleireskred i Gjerdrum og en lang og krevende redningsaksjon ble satt i gang. Redningsaksjonen involverte en rekke aktører, både offentlige, private og frivillige organisasjoner. Samvirke er et sentralt begrep i slike redningsaksjoner. Kvikkleireskredet på Gjerdrum viste hvordan det norske beredskapssamvirket fungerer på sitt beste. I tillegg til et godt ... -
On the time-dependence of climate sensitivity
(Doctoral thesis; Doktorgradsavhandling, 2023-11-03)Climate sensitivity is the change of the global-mean surface temperature in response to a doubling of the CO2 concentration. It is typically used to describe climate change and to inform decision-making for mitigation and adaptation. Climate sensitivity is often estimated in numerical climate model experiments. A remarkable result from these experiments is that climate sensitivity changes over time. ... -
Origin and Economic Potential of Lithium-mineralized Granitic Pegmatites in Helgeland, North Norway
(Mastergradsoppgave; Master thesis, 2023-08-04)A comprehensive set of analytical techniques, encompassing geological, petrographic, mineralogical, and zircon U-Pb-Hf isotopic compositions, was employed to investigate a relatively poorly known pegmatite field located in Helgeland, North Norway. The Paleoproterozoic basement gneisses in the area have U-Pb zircon crystallization ages between 1870 ± 12 and 1811 ± 6 Ma, meaning that they belong to ... -
Exploring late Pleistocene bioturbation on Yermak Plateau to assess sea-ice conditions and primary productivity through the Ethological Ichno Quotient
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-13)Central Arctic, interglacial intervals have traditionally been associated with diverse and intense bioturbation, and abundant foraminifera, interpreted as indicating relatively low sea-ice concentrations and productive surface waters, while glacial intervals, typically barren, support the inverse. In this respect, the Yermak Plateau is anomalous. Biomarker studies suggest that glacial intervals were ... -
Selective Imputation for Multivariate Time Series Datasets with Missing Values
(Journal article; Tidsskriftartikkel, 2023-01-31)Multivariate time series often contain missing values for reasons such as failures in data collection mechanisms. Since these missing values can complicate the analysis of time series data, imputation techniques are typically used to deal with this issue. However, the quality of the imputation directly affects the performance of downstream tasks. In this paper, we propose a selective imputation ... -
The South American monsoon approaches a critical transition in response to deforestation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-04)The Amazon rainforest is threatened by land-use change and increasing drought and fire frequency. Studies suggest an abrupt dieback of large parts of the rainforest after partial forest loss, but the critical threshold, underlying mechanisms, and possible impacts of forest degradation on the monsoon circulation remain uncertain. Here, we use a nonlinear dynamical model of the moisture transport ... -
Radar studies of plasma parameters in the polar cap and the auroral zone
(Doctoral thesis; Doktorgradsavhandling, 2018-04-11)Incoherent scatter radar measurements are an important source for studies of ionospheric plasma parameters. Data from the EISCAT Svalbard radar (ESR), which covers the polar cap and cusp, and from the EISCAT Tromsø radars, which covers the auroral zone, can be used to obtain information about the electron density, electron- and ion temperature, and line-of-sight plasma velocity. As the ESR started ...