Viser treff 161-180 av 947

    • Reconstruction of intermittent time series as a superposition of pulses 

      Ahmed, Sajidah; Garcia, Odd Erik; Theodorsen, Audun (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05)
      Fluctuations in a vast range of physical systems can be described as a superposition of uncorrelated pulses with a fixed shape, a process commonly referred to as a (generalized) shot noise or a filtered Poisson process. In this paper, we present a systematic study of a deconvolution method to estimate the arrival times and amplitudes of the pulses from realizations of such processes. The method shows ...
    • On Importance of Off-Diagonal Elements in the Polarimetric Covariance Matrix: A Sea Ice Application Perspective 

      Ratha, Debanshu; Doulgeris, Anthony Paul; Marinoni, Andrea; Eltoft, Torbjørn (Conference object; Konferansebidrag, 2023-06)
    • Viewing life without labels under optical microscopes 

      Ghosh, Biswajoy; Agarwal, Krishna (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-25)
      Optical microscopes today have pushed the limits of speed, quality, and observable space in biological specimens revolutionizing how we view life today. Further, specific labeling of samples for imaging has provided insight into how life functions. This enabled label-based microscopy to percolate and integrate into mainstream life science research. However, the use of labelfree microscopy has been ...
    • Deep generative models for reject inference in credit scoring 

      Andrade Mancisidor, Rogelio; Kampffmeyer, Michael; Aas, Kjersti; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-21)
      Credit scoring models based on accepted applications may be biased and their consequences can have a statistical and economic impact. Reject inference is the process of attempting to infer the creditworthiness status of the rejected applications. Inspired by the promising results of semi-supervised deep generative models, this research develops two novel Bayesian models for reject inference in credit ...
    • Learning latent representations of bank customers with the Variational Autoencoder 

      Andrade Mancisidor, Rogelio; Kampffmeyer, Michael; Aas, Kjersti; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-15)
      Learning data representations that reflect the customers’ creditworthiness can improve marketing campaigns, customer relationship management, data and process management or the credit risk assessment in retail banks. In this research, we show that it is possible to steer data representations in the latent space of the Variational Autoencoder (VAE) using a semi-supervised learning framework and a ...
    • An investigation on the damping ratio of marine oil slicks in synthetic aperture radar imagery 

      Quigley, Cornelius Patrick; Johansson, Malin; Jones, Cathleen Elaine (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-12)
      The damping ratio has recently been used to indicate the relative internal oil thickness within oil slicks observed in synthetic aperture radar (SAR) imagery. However, there exists no well-defined and evaluated methodology for calculating the damping ratio. In this study, we review prior work regarding the damping ratio and outline its theoretical and practical aspects. We show that the most often ...
    • Critical echo state network dynamics by means of Fisher information maximization 

      Bianchi, Filippo Maria; Livi, Lorenzo; Jenssen, Robert; Alippi, Cesare (Chapter; Bokkapittel, 2017-07-03)
      The computational capability of an Echo State Network (ESN), expressed in terms of low prediction error and high short-term memory capacity, is maximized on the so-called “edge of criticality”. In this paper we present a novel, unsupervised approach to identify this edge and, accordingly, we determine hyperparameters configuration that maximize network performance. The proposed method is ...
    • Temporal overdrive recurrent neural network 

      Bianchi, Filippo Maria; Kampffmeyer, Michael C.; Maiorino, Enrico; Jenssen, Robert (Chapter; Bokkapittel, 2017-07-03)
      In this work we present a novel recurrent neural network architecture designed to model systems characterized by multiple characteristic timescales in their dynamics. The proposed network is composed by several recurrent groups of neurons that are trained to separately adapt to each timescale, in order to improve the system identification process. We test our framework on time series prediction tasks ...
    • Large-Scale Mapping of Small Roads in Lidar Images Using Deep Convolutional Neural Networks 

      Salberg, Arnt Børre; Trier, Øivind Due; Kampffmeyer, Michael C. (Chapter; Bokkapittel, 2017-05-19)
      Detailed and complete mapping of forest roads is important for the forest industry since they are used for timber transport by trucks with long trailers. This paper proposes a new automatic method for large-scale mapping forest roads from airborne laser scanning data. The method is based on a fully convolutional neural network that performs end-to-end segmentation. To train the network, a large set ...
    • Eddy Detection in the Marginal Ice Zone with Sentinel-1 Data Using YOLOv5 

      Khachatrian, Eduard; Sandalyuk, Nikita V.; Lozou, Pigi (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-24)
      The automatic detection and analysis of ocean eddies in the marginal ice zone via remote sensing is a very challenging task but of critical importance for scientific applications and anthropogenic activities. Therefore, as one of the first steps toward the automation of the eddy detection process, we investigated the potential of applying YOLOv5, a deep convolutional neural network architecture, to ...
    • SAR and Passive Microwave Fusion Scheme: A Test Case on Sentinel-1/AMSR-2 for Sea Ice Classification 

      Khachatrian, Eduard; Dierking, Wolfgang; Chlaily, Saloua; Eltoft, Torbjørn; Dinessen, Frode; Hughes, Nick; Marinoni, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-14)
      The most common source of information about sea ice conditions is remote sensing data, especially images obtained from synthetic aperture radar (SAR) and passive microwave radiometers (PMR). Here we introduce an adaptive fusion scheme based on Graph Laplacians that allows us to retrieve the most relevant information from satellite images. In a first test case, we explore the potential of sea ice ...
    • Droner som FKT - bruk av droner som forebyggende tiltak i beitenæringen 

      Winje, Erlend; Bjørn, Tor-Arne; Hansen, Inger; Meisingset, Erling; Haugen, Atilla; Heppelmann, Joachim Bernd; Myhre, Jonas Nordhaug; Wagner, Gabriela (Research report; Forskningsrapport, 2023)
      Utmarksbeitende dyr er utsatt for angrep fra fredet rovvilt. I oppdrag fra rovviltnemnda i region 6 Midt-Norge undersøker vi den mulige nytteverdien av droner i åpen kategori som forebyggende- og konfliktdempende tiltak (FKT). Utredningen er basert på informasjon fra intervjuer, faglitteratur og dronetestflygninger.Droner som FKT kan brukes under (1) tilsyn, (2) flytting av dyr fra rovdyrutsatte ...
    • Label-free superior contrast with c-band ultra-violet extinction microscopy 

      Wolfson, Deanna; Opstad, Ida Sundvor; Hansen, Daniel Henry; Mao, Hong; Ahluwalia, Balpreet Singh; Ströhl, Florian (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-03)
      In 1934, Frits Zernike demonstrated that it is possible to exploit the sample’s refractive index to obtain superior contrast images of biological cells. The refractive index contrast of a cell surrounded by media yields a change in the phase and intensity of the transmitted light wave. This change can be due to either scattering or absorption caused by the sample. Most cells are transparent at visible ...
    • Rapid prototyping of 1xN multifocus gratings via additive direct laser writing 

      Reischke, Marie; Vanderpoorten, Oliver; Ströhl, Florian (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-05)
      Multifocus gratings (MFGs) enable microscopes and other imaging systems to record entire Z-stacks of images in a single camera exposure. The exact grating shape depends on microscope parameters like wavelength and magnification and defines the multiplexing onto a grid of MxN Z-slices. To facilitate the swift production and alteration of MFGs for a system and application at hand, we have developed ...
    • Deep Semi-Supervised Semantic Segmentation in Multi-Frequency Echosounder Data 

      Choi, Changkyu; Kampffmeyer, Michael; Jenssen, Robert; Handegard, Nils Olav; Salberg, Arnt-Børre (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-01)
      Multi-frequency echosounder data can provide a broad understanding of the underwater environment in a non-invasive manner. The analysis of echosounder data is, hence, a topic of great importance for the marine ecosystem. Semantic segmentation, a deep learning based analysis method predicting the class attribute of each acoustic intensity, has recently been in the spotlight of the fisheries and aquatic ...
    • Studentaktiv læring med store studentgrupper – fordeler og ulemper med gruppediskusjon i pollbasert undervisning 

      Coucheron, David Andre; Beerepoot, Maarten (Conference object; Konferansebidrag, 2023-03)
      To viktige prinsipper for å øke studentenes læring i undervisning er aktiv deltagelse og formativ vurdering. Innføring av disse prinsippene i undervisning med store studentgrupper kan imidlertid by på utfordringer. Løsningen kan være å bruke flervalgsoppgaver i undervisningen med påfølgende formativ vurdering av faglæreren, en undervisningsform som vi her kaller pollbasert undervisning. I dette ...
    • On the Exploitation of Heterophily in Graph-Based Multimodal Remote Sensing Data Analysis 

      Taelman, Catherine Cecilia A; Chlaily, Saloua; Khachatrian, Eduard; Van Der Sommen, Fons; Marinoni, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2022)
      The field of Earth observation is dealing with increasingly large, multimodal data sets. An important processing step consists of providing these data sets with labels. However, standard label propagation algorithms cannot be applied to multimodal remote sensing data for two reasons. First, multimodal data is heterogeneous while classic label propagation algorithms assume a homogeneous network. ...
    • Modeling Solar Orbiter dust detection rates in the inner heliosphere as a Poisson process 

      Kociscak, Samuel; Kvammen, Andreas; Mann, Ingrid; Sørbye, Sigrunn Holbek; Theodorsen, Audun; Zaslavsky, Arnaud (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-20)
      Context. Solar Orbiter provides dust detection capability in the inner heliosphere, but estimating physical properties of detected dust from the collected data is far from straightforward.<p> <p>Aims. First, a physical model for dust collection considering a Poisson process is formulated. Second, it is shown that dust on hyperbolic orbits is responsible for the majority of dust detections with ...
    • CIRFA Cruise 2022. Cruise report. 

      Dierking, Wolfgang Fritz Otto; Schneider, Andrea; Eltoft, Torbjørn; Gerland, Sebastian (Research report; Forskningsrapport, 2022)
      This report gives a complete record of all data sets that were collected during the CIRFA cruise 22 April - 9 May 2022, with RV Kronprins Haakon, to the western Fram Strait and the East Greenland Sea. IMR cruise ID 2022704. The CIRFA-cruise 2022 was funded by UiT the Arctic University of Norway, the European Space Agency (RFP Response No 3-17845), the Research Council of Norway (RCN project ...
    • The Kernelized Taylor Diagram 

      Wickstrøm, Kristoffer; Johnson, Juan Emmanuel; Løkse, Sigurd Eivindson; Camps-Valls, Gusatu; Mikalsen, Karl Øyvind; Kampffmeyer, Michael; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-02)
      This paper presents the kernelized Taylor diagram, a graphical framework for visualizing similarities between data populations. The kernelized Taylor diagram builds on the widely used Taylor diagram, which is used to visualize similarities between populations. However, the Taylor diagram has several limitations such as not capturing non-linear relationships and sensitivity to outliers. To address ...