Search results for "Matematik"
showing 10 items of 727 documents
Distributed Learning Automata-based S-learning scheme for classification
2019
This paper proposes a novel classifier based on the theory of Learning Automata (LA), reckoned to as PolyLA. The essence of our scheme is to search for a separator in the feature space by imposing an LA-based random walk in a grid system. To each node in the grid, we attach an LA whose actions are the choices of the edges forming a separator. The walk is self-enclosing, and a new random walk is started whenever the walker returns to the starting node forming a closed classification path yielding a many-edged polygon. In our approach, the different LA attached to the different nodes search for a polygon that best encircles and separates each class. Based on the obtained polygons, we perform …
Ungdom og e-demokrati : hvilke ønsker og forventninger har ungdom til e-demokrati?
2007
Masteroppgave i informasjonssystemer 2007 - Høgskolen i Agder, Kristiansand E-demokrati er et satsningsområde i offentlig sektor. Det har i Norge vært synkende deltagelse i valg både til Storting og kommunevalg ved de siste valgene. Ungdom i aldersgruppen 18 til 21 år har lavere oppslutning rundt valgene enn eldre aldersgrupper. Flere mener at e-demokrati kan bidra til å øke oppslutning rundt demokratiet og valgene. I denne sammenheng er ungdom en viktig målgruppe. Vi har sett nærmere på e-demokrati rettet mot ungdom. Målet for denne masteroppgaven har vært å forstå hvilke ønsker og forventninger ungdom har til informasjonssystemer innen for edemokrati. For å besvare dette spørsmålet har vi…
Design of an Air Management System for a Dry Room and Utilization of Waste Heat
2021
Master's thesis in Renewable energy (ENE500) This thesis presents the design of an air management system used in a dry room fora lithium-ion battery factory using a Matlab/Simulink environment. The sizing of the system is based on the 32 GWh battery factory, currently under construction by Morrow Batteries in Arendal, Norway. The generic air management system from the literature review was used as a base for the general layout and initial values. Combining coolers and a desiccant dehumidification wheel was the optimal solution for the dehumidification system. The molecular sieve was the selected desiccant due to its high performance at low relative humidity. The outlet air quality from the …
Role of protozooplankton in the diet of North Sea autumn spawning herring (Clupea harengus) larvae
2022
AbstractThe role of small prey (< 200 µm) in larval marine fish nutrition is largely understudied. Here, we explore the contribution of protozooplankton (PZP 20–200 µm) to larval fish diets, compared to metazoan microzooplankton (MZP 55–200 µm). More specifically, we tested whether the contribution of PZP increased during the low productivity season and decreased as larvae grow. We used North Sea autumn spawning herring (Clupea harengus) as a case study, as it is a key species with high commercial and ecological importance. In autumn and winter, the potential PZP and MZP prey was dominated by cells < 50 µm (mainly Gymnodiniales, Pronoctiluca pelagica,Tripos spp. and Strombidium spp.),…
Dynamics of asteroid systems post-rotational fission
2022
Asteroid binaries found amongst the Near-Earth objects are believed to have formed from rotational fission. In this paper, we aim to study the dynamical evolution of asteroid systems the moment after fission. The initial condition is modelled as a contact binary, similar to that of Boldrin et al. (2016). Both bodies are modelled as ellipsoids, and the secondary is given an initial rotation angle about its body-fixed $y$-axis. Moreover, we consider six different cases, three where the density of the secondary varies, and three where we vary its shape. The simulations consider 45 different initial tilt angles of the secondary, each with 37 different mass ratios. We start the dynamical simulat…
Explicit incorporation of spatial variability in a biomass dynamics assessment model
2021
Abstract The sustainable management of fisheries has largely relied on stock assessment models that assume stocks are homogeneous throughout their domain. However, ignoring complex underlying spatial patterns can lead to increased risk of failures in management. Utilizing geostatistical approaches in conjunction with a traditional fishery biomass dynamics model, we develop a spatially-explicit modelling framework that treats the underlying population dynamics as spatial processes. Simulation experiments demonstrate that this approach reliably estimates variance parameters and accurately captures true patterns of population change. We further demonstrate the utility of our modelling framewor…
The interplay between terrestrial organic matter and benthic macrofauna: Framework, synthesis, and perspectives
2023
Ecosystems are shaped by physical, chemical, and biological drivers, which affect the quality and quantity of basal energy sources, with impacts that cascade to higher trophic levels. In coastal, shelf, and marine habitats, terrestrial-derived organic matter (ter-OM) can be a key driver of ecosystem structure and function. Climate change is expected to alter land–ocean connectivity in many regions, with a broad range of potential consequences for impacted ecosystems, particularly in the coastal zone. The benthic compartment is an important link between the large organic carbon pools stored on land and the marine environment. At the same time, the macrofauna plays a key role in the processin…
Tensions in the communication of science advice on fish and fisheries: northern cod, species at risk, sustainable seafood
2022
Abstract Providing science-based advice can be challenging. Personal in its reflections, the story that follows asks throughout: What constitutes an appropriate model for the communication of science-based advice that best serves society? The first “front line,” in 1992, involved tenuous hypotheses on the collapse and recovery of Newfoundland's Northern cod (Gadus morhua), raising troubling questions about political influence on science-based advice and on its integrity. These questions subsequently motivated a critique written with two colleagues on the communication of science to decision-makers, provoking a telling invective from a government department in defence of the status quo. The …
Host in reserve: The role of common shrews (Sorex araneus) as a supplementary source of tick hosts in small mammal communities influenced by rodent p…
2022
Rodents often act as important hosts for ticks and as pathogen reservoirs. At north -ern latitudes, rodents often undergo multi- annual population cycles, and the peri -odic absence of certain hosts may inhibit the survival and recruitment of ticks. We investigated the potential role of common shrews (Sorex araneus) to serve as a sup -plementary host source to immature life stages (larvae and nymphs) of a generalist tick Ixodes ricinus and a small mammal specialist tick I. trianguliceps, during decreas-ing abundances of bank voles (Myodes glareolus). We used generalized mixed models to test whether ticks would have a propensity to parasitize a certain host species dependent on host populati…
FishSizer: Software solution for efficiently measuring larval fish size
2022
Length and depth of fish larvae are part of the fundamental measurements in many marine ecology studies involving early fish life history. Until now, obtaining these measurements has required intensive manual labor and the risk of inter- and intra-observer variability. We developed an open-source software solution to semi-automate the measurement process and thereby reduce both time consumption and technical variability. Using contrast-based edge detection, the software segments images of a fish larva into “larva” and “background.” Length and depth are extracted from the “larva” segmentation while taking curvature of the larva into consideration. The graphical user interface optimizes workf…