• Hyperspectral imaging for the detection of glioblastoma tumor cells in H&E slides using convolution neural networks 

      Ortega, S.; Halicek, M.; Fabelo, H.; Camacho, R.S.; Plaza, M.L.; Godtliebsen, Fred; Callico, G. M.; Fei, Baowei (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-30)
      Hyperspectral imaging (HSI) technology has demonstrated potential to provide useful information about the chemical composition of tissue and its morphological features in a single image modality. Deep learning (DL) techniques have demonstrated the ability of automatic feature extraction from data for a successful classification. In this study, we exploit HSI and DL for the automatic differentiation ...
    • In-Silico Evaluation of Glucose Regulation Using Policy Gradient Reinforcement Learning for Patients with Type 1 Diabetes Mellitus 

      Myhre, Jonas Nordhaug; Tejedor Hernandez, Miguel Angel; Launonen, Ilkka Kalervo; El Fathi, Anas; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-11)
      In this paper, we test and evaluate policy gradient reinforcement learning for automated blood glucose control in patients with Type 1 Diabetes Mellitus. Recent research has shown that reinforcement learning is a promising approach to accommodate the need for individualized blood glucose level control algorithms. The motivation for using policy gradient algorithms comes from the fact that adaptively ...
    • Machine Learning in Chronic Pain Research: A Scoping Review 

      Jenssen, Marit Dagny Kristine; Bakkevoll, Per Atle; Ngo, Phuong; Budrionis, Andrius; Fagerlund, Asbjørn Johansen; Tayefi, Maryam; Bellika, Johan Gustav; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-02)
      Given the high prevalence and associated cost of chronic pain, it has a significant impact on individuals and society. Improvements in the treatment and management of chronic pain may increase patients’ quality of life and reduce societal costs. In this paper, we evaluate state-of-the-art machine learning approaches in chronic pain research. A literature search was conducted using the PubMed, IEEE ...
    • Model-driven diabetes care: study protocol for a randomized controlled trial 

      Skrøvseth, Stein Olav; Årsand, Eirik; Godtliebsen, Fred; Joakimsen, Ragnar Martin (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Background: People with type 1 diabetes who use electronic self-help tools register a large amount of information about their disease on their participating devices; however, this information is rarely utilized beyond the immediate investigation. We have developed a diabetes diary for mobile phones and a statistics-based feedback module, which we have named Diastat, to give data-driven feedback ...
    • A novel scale-space approach for multinormality testing and the k-sample problem in the high dimension low sample size scenario 

      Hindberg, Kristian; Hannig, Jan; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-22)
      Two classical multivariate statistical problems, testing of multivariate normality and the <i>k</i>-sample problem, are explored by a novel analysis on several resolutions simultaneously. The presented methods do not invert any estimated covariance matrix. Thereby, the methods work in the High Dimension Low Sample Size situation, i.e. when <i>n</i> ≤ <i>p</i>. The output, a significance map, is ...
    • On Data-Independent Properties for Density-Based Dissimilarity Measures in Hybrid Clustering 

      Møllersen, Kajsa; Dhar, Subhra; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-12)
      Hybrid clustering combines partitional and hierarchical clustering for computational effectiveness and versatility in cluster shape. In such clustering, a dissimilarity measure plays a crucial role in the hierarchical merging. The dissimilarity measure has great impact on the final clustering, and data-independent properties are needed to choose the right dissimilarity measure for the problem ...
    • On hybrid classification using model assisted posterior estimates 

      Ghosh, Anil K.; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      Traditional parametric and nonparametric classifiers used for statistical pattern recognition have their own strengths and limitations. While parametric methods assume some specific parametric models for density functions or posterior probabilities of competing classes, nonparametric methods are free from such assumptions. So, when these model assumptions are correct, parametric methods outperform ...
    • Pairwise scale space comparison of time series with application to climate research 

      Godtliebsen, Fred; Holmström, L.; Miettinen, A.; Erästö, P.; Divine, Dmitry V; Koc, Nalan (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      In this paper, we study how sea surface temperature variations in the North Atlantic and the Norwegian Sea are correlated with the climate in the Northern Hemisphere in late Holocene. The analysis is performed by testing statistical hypotheses through novel scale space methodologies. In late Holocene, the proposed techniques reveal that the climate development in the subpolar North Atlantic has been ...
    • A Probabilistic Bag-to-Class Approach to Multiple-Instance Learning 

      Møllersen, Kajsa; Hardeberg, Jon Yngve; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-26)
      Multi-instance (MI) learning is a branch of machine learning, where each object (bag) consists of multiple feature vectors (instances)—for example, an image consisting of multiple patches and their corresponding feature vectors. In MI classification, each bag in the training set has a class label, but the instances are unlabeled. The instances are most commonly regarded as a set of points in a ...
    • A propagation-separation approach to estimate the autocorrelation in a time-series 

      Divine, Dmitry V; Polzehl, J; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2008)
    • Recent advances in hyperspectral imaging for melanoma detection 

      Johansen, Thomas Haugland; Møllersen, Kajsa; Ortega, Samuel; Fabelo, Himar; Garcia, Aday; Callico, Gustavo; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-22)
      Skin cancer is one of the most common types of cancer. Skin cancers are classified as nonmelanoma and melanoma, with the first type being the most frequent and the second type being the most deadly. The key to effective treatment of skin cancer is early detection. With the recent increase of computational power, the number of algorithms to detect and classify skin lesions has increased. The overall ...
    • Reinforcement learning application in diabetes blood glucose control: A systematic review 

      Tejedor Hernandez, Miguel Angel; Woldaregay, Ashenafi Zebene; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-21)
      <p>Background: Reinforcement learning (RL) is a computational approach to understanding and automating goal-directed learning and decision-making. It is designed for problems which include a learning agent interacting with its environment to achieve a goal. For example, blood glucose (BG) control in diabetes mellitus (DM), where the learning agent and its environment are the controller and the body ...
    • Risk-Averse Food Recommendation Using Bayesian Feedforward Neural Networks for Patients with Type 1 Diabetes Doing Physical Activities 

      Ngo, Phuong; Tejedor Hernandez, Miguel Angel; Tayefi, Maryam; Chomutare, Taridzo; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-12)
      <p><i>Background.</i> Since physical activity has a high impact on patients with type 1 diabetes and the risk of hypoglycemia (low blood glucose levels) is significantly higher during and after physical activities, an automatic method to provide a personalized recommendation is needed to improve the blood glucose management and harness the benefits of physical activities. This paper aims to reduce ...
    • Scale Space Methods for Analysis of Type 2 Diabetes Patients' Blood Glucose Values 

      Skrøvseth, Stein Olav; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      We describe how scale space methods can be used for quantitative analysis of blood glucose concentrations from type 2 diabetes patients. Blood glucose values were recorded voluntarily by the patients over one full year as part of a self-management process, where the timeand frequency of the recordings are decided by the patients. This makes a unique datasetin its extent, though with a large variation ...
    • A semiautomatic tool for prostate segmentation in radiotherapy treatment planning 

      Schulz, Jörn; Skrøvseth, Stein Olav; Tømmerås, Veronika Kristine; Marienhagen, Kirsten; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-01-25)
    • Soft thresholding schemes for multiple signal classification algorithm 

      Acuña Maldonado, Sebastian Andres; Opstad, Ida Sundvor; Godtliebsen, Fred; Ahluwalia, Balpreet Singh; Agarwal, Krishna (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-28)
      Multiple signal classification algorithm (MUSICAL) exploits temporal fluctuations in fluorescence intensity to perform super-resolution microscopy by computing the value of a super-resolving indicator function across a fine sample grid. A key step in the algorithm is the separation of the measurements into signal and noise subspaces, based on a single user-specified parameter called the threshold. ...
    • Sub sea surface temperatures in the Polar North Atlantic during the Holocene: Planktic foraminiferal Mg/Ca temperature reconstructions 

      Sørensen, Steffen Aagaard; Husum, Katrine; Hald, Morten; Marchitto, Thomas; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Holocene sea surface temperatures in the eastern Fram Strait are reconstructed based on Mg/Ca ratios measured on the planktic foraminifer Neogloboquadrina pachyderma (sin). The reconstructed sub sea surface temperatures (sSSTMg/Ca) fluctuate markedly during the earliest Holocene at ~11.7 and 10.5 kyr BP. This is probably in response to the varying presence of sea-ice and deglacial meltwater. Between ...
    • Surface water conditions and calcium carbonate preservation in the Fram Strait during marine isotope stage 2, 28.8–15.4 kyr 

      Zamelczyk, Katarzyna; Rasmussen, Tine Lander; Husum, Katrine; Godtliebsen, Fred; Hald, Morten (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-01-14)
      We present a high-resolution record of calcium carbonate preservation alongside the distribution pattern of planktic foraminifera from the Fram Strait. The record covers the marine isotope stage (MIS) 2, 28.8 to 15.4 kyr, including the Last Glacial Maximum (LGM) and the early deglaciation in multidecadal temporal resolution. The investigation is based on the distribution patterns of planktic ...
    • Thousand years of winter surface air temperature variations in Svalbard and northern Norway reconstructed from ice-core data 

      Divine, Dmitry V; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      Two isotopic ice core records from western Svalbard are calibrated to reconstruct more than 1000 years of past winter surface air temperature variations in Longyearbyen, Svalbard, and Vardø, northern Norway. Analysis of the derived reconstructions suggests that the climate evolution of the last millennium in these study areas comprises three major sub-periods. The cooling stage in Svalbard (ca. ...
    • Using anchors from free text in electronic health records to diagnose postoperative delirium 

      Mikalsen, Karl Øyvind; Soguero-Ruiz, Cristina; Jensen, Kasper; Hindberg, Kristian; Gran, Mads; Revhaug, Arthur; Lindsetmo, Rolv-Ole; Skrøvseth, Stein Olav; Godtliebsen, Fred; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-19)
      Objectives:<br> Postoperative delirium is a common complication after major surgery among the elderly. Despite its potentially serious consequences, the complication often goes undetected and undiagnosed. In order to provide diagnosis support one could potentially exploit the information hidden in free text documents from electronic health records usin ...