• Dissecting deep neural networks for better medical image classification and classification understanding 

      Hicks, Steven Alexander; Riegler, Michael; Pogorelov, Konstantin; Ånonsen, Kim Vidar; de Lange, Thomas; Johansen, Dag; Jeppsson, Mattis; Randel, Kristin Ranheim; Eskeland, Sigrun Losada; Halvorsen, Pål (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-23)
      Neural networks, in the context of deep learning, show much promise in becoming an important tool with the purpose assisting medical doctors in disease detection during patient examinations. However, the current state of deep learning is something of a "black box", making it very difficult to understand what internal processes lead to a given result. This is not only true for non-technical users but ...
    • DoubleU-Net: A Deep Convolutional Neural Network for Medical Image Segmentation 

      Jha, Debesh; Riegler, Michael Alexander; Johansen, Dag; Halvorsen, Pål; Johansen, Håvard D. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-01)
      Semantic image segmentation is the process of labeling each pixel of an image with its corresponding class. An encoder-decoder based approach, like U-Net and its variants, is a popular strategy for solving medical image segmentation tasks. To improve the performance of U-Net on various segmentation tasks, we propose a novel architecture called DoubleU-Net, which is a combination of two U-Net ...
    • Dynamically loading mobile/cloud assemblies 

      Pettersen, Robert; Johansen, Håvard D.; Valvåg, Steffen Viken; Johansen, Dag (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-20)
      Distributed applications that span mobile devices, computing clusters, and cloud services, require robust and flexible mechanisms for dynamically loading code. This paper describes lady: a system that augments the .net platform with a highly reliable mechanism for resolving and loading assemblies, and arranges for safe execution of partially trusted code. Key benefits of lady are the low latency and ...
    • Efficient disease detection in gastrointestinal videos – global features versus neural networks 

      Pogorelov, Konstantin; Riegler, Michael; Eskeland, Sigrun Losada; de Lange, Thomas; Johansen, Dag; Griwodz, Carsten; Schmidt, Peter Thelin; Halvorsen, Pål (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-19)
      Analysis of medical videos from the human gastrointestinal (GI) tract for detection and localization of abnormalities like lesions and diseases requires both high precision and recall. Additionally, it is important to support efficient, real-time processing for live feedback during (i) standard colonoscopies and (ii) scalability for massive population-based screening, which we conjecture can be done ...
    • Efficient live and on-demand tiled HEVC 360 VR video streaming 

      Jeppsson, Mattis; Espeland, Håvard; Kupka, Tomas; Langseth, Ragnar; Petlund, Andreas; Peng, Qiaoqiao; Xue, Chuansong; Johansen, Dag; Pogorelov, Konstantin; Stensland, Håkon Kvale; Griwodz, Carsten; Riegler, Michael; Halvorsen, Pål (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      360∘ panorama video displayed through Virtual Reality (VR) glasses or large screens offers immersive user experiences, but as such technology becomes commonplace, the need for efficient streaming methods of such high-bitrate videos arises. In this respect, the attention that 360∘ panorama video has received lately is huge. Many methods have already been proposed, and in this paper, we shed more light ...
    • Enforcing Privacy Policies with Meta-Code 

      Johansen, Håvard; Birrell, Eleanor; Van Renesse, Robbert; Schneider, Fred B.; Stenhaug, Magnus; Johansen, Dag (Konferansebidrag; Conference object, 2015)
      This paper proposes a mechanism for expressing and enforcing security policies for shared data. Security policies are expressed as stateful meta-code operations; meta-code can express a broad class of policies, including access-based policies, use-based policies, obligations, and sticky policies with declassification. The meta-code is interposed in the filesystem access path to ensure policy ...
    • Engineering push-based web services 

      Brenna, Lars; Johansen, Dag (Research report; Forskningsrapport, 2005)
      Much of the content of popular Internet information sources is highly dynamic: urgent in nature and sometimes relevant only for a short time. The typical approach to querying such dynamic sources is polling for updates often.1 This strains the traditional pull-based Internet and wastes network resources on transmitting redundant information. This paper focuses on how to structure the Internet to ...
    • Environment mobility. Moving the desktop around. 

      Renesse, Robbert van; Johansen, Dag; Johansen, Håvard (Research report; Forskningsrapport, 2004)
      In this position paper, we focus on issues related to middleware support for software mobility in ad hoc and pervasive systems. In particular, we are interested in moving the computational environment of a mobile user following his trajectory. We present details of WAIFARER, a prototype implementation that automatically saves and restores application level state to support this mobility. Security, ...
    • Exploration of Different Time Series Models for Soccer Athlete Performance Prediction 

      Kulakou, Siarhei; Ragab, Nourhan; Midoglu, Cise; Boeker, Matthias; Johansen, Dag; Riegler, Michael; Halvorsen, Pål (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-29)
      Professional sports achievements combine not only the individual physical abilities of athletes but also many modern technologies in areas such as medicine, equipment production, nutrition, and physical and mental health monitoring. In this work, we address the problem of predicting soccer players’ ability to perform, from subjective self-reported wellness parameters collected using a commercially ...
    • An extensible software architecture for mobile components 

      Marzullo, Keith; Johansen, Dag; Lauvset, Kåre J. (Research report; Forskningsrapport, 2000-10-06)
      This paper presents a generic software architecture for large-scale distributed applications where mobile agents are an integral part. We have devised this architecture through completion of a series of mobile agent systems and associated applications over the last 8 years.
    • FANet: A Feedback Attention Network for Improved Biomedical Image Segmentation 

      Jha, Debesh; Riegler, Michael; Johansen, Håvard D.; Johansen, Dag; Rittscher, Jens; Halvorsen, Pål; Ali, Sharib (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-25)
      The increase of available large clinical and experimental datasets has contributed to a substantial amount of important contributions in the area of biomedical image analysis. Image segmentation, which is crucial for any quantitative analysis, has especially attracted attention. Recent hardware advancement has led to the success of deep learning approaches. However, although deep learning models are ...
    • File System Support for Privacy-Preserving Analysis and Forensics in Low-Bandwidth Edge Environments 

      Ovesen, Aril Bernhard; Nordmo, Tor-Arne Schmidt; Johansen, Håvard D.; Riegler, Michael Alexander; Halvorsen, Pål; Johansen, Dag (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-18)
      In this paper, we present initial results from our distributed edge systems research in the domain of sustainable harvesting of common good resources in the Arctic Ocean. Specifically, we are developing a digital platform for real-time privacy-preserving sustainability management in the domain of commercial fishery surveillance operations. This is in response to potentially privacy-infringing mandates ...
    • Fireflies: A Secure and Scalable Membership and Gossip Service 

      Johansen, Håvard; Van Renesse, Robbert; Vigfusson, Ymir; Johansen, Dag (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-06)
      An attacker who controls a computer in an overlay network can effectively control the entire overlay network if the mechanism managing membership information can successfully be targeted. This article describes Fireflies, an overlay network protocol that fights such attacks by organizing members in a verifiable pseudorandom structure so that an intruder cannot incorrectly modify the membership views ...
    • FirePatch. Secure and time-critical dissemination of patches 

      Johansen, Håvard; Rennesse, Robbert van; Johansen, Dag (Research report; Forskningsrapport, 2006)
      Because software security patches relay information about vulnerabilities, they can be reverse engineered into exploits. Tools for doing this already exist. As a result, there is a race between hackers and end-users to first obtain patches. In this paper we present and evaluate FirePatch, an intrusion-tolerant dissemination mechanism that combines encryption, replication, and sandboxing such that ...
    • Fish AI: Sustainable Commercial Fishing Challenge 

      Nordmo, Tor-Arne Schmidt; Kvalsvik, Ove; Kvalsund, Svein Ove; Hansen, Birte; Halvorsen, Pål; Hicks, Steven; Johansen, Dag; Johansen, Håvard D.; Riegler, Michael Alexander (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-02)
      FishAI: Sustainable Commercial Fishingis the second chal-lenge at theNordic AI Meetfollowing the successful MedAI,which had a focus on medical image segmentation and trans-parency in machine learning (ML)-based systems. FishAI fo-cuses on a new domain, namely, commercial fishing and howto make it more sustainable with the help of machine learning.A range of public available datasets is used to tackle ...
    • Fishing Trawler Event Detection: An Important Step Towards Digitization of Sustainable Fishing 

      Nordmo, Tor-Arne Schmidt; Ovesen, Aril Bernhard; Dagenborg, Håvard; Halvorsen, Pål; Riegler, Michael Alexander; Johansen, Dag (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 ...
    • HyperKvasir, a comprehensive multi-class image and video dataset for gastrointestinal endoscopy 

      Borgli, Hanna; Thambawita, Vajira; Smedsrud, Pia H; Hicks, Steven; Jha, Debesh; Eskeland, Sigrun Losada; Randel, Kristin Ranheim; Pogorelov, Konstantin; Lux, Mathias; Dang Nguyen, Duc Tien; Johansen, Dag; Griwodz, Carsten; Stensland, Håkon Kvale; Garcia-Ceja, Enrique; Schmidt, Peter T; Hammer, Hugo Lewi; Riegler, Michael; Halvorsen, Pål; de Lange, Thomas (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-28)
      Artificial intelligence is currently a hot topic in medicine. However, medical data is often sparse and hard to obtain due to legal restrictions and lack of medical personnel for the cumbersome and tedious process to manually label training data. These constraints make it difficult to develop systems for automatic analysis, like detecting disease or other lesions. In this respect, this article ...
    • Improved maximal strength is not associated with improvements in sprint time or jump height in high-level female football players: a clusterrendomized controlled trial 

      Pedersen, Sigurd; Heitmann, Kim Arne; Sagelv, Edvard Hamnvik; Johansen, Dag; Pettersen, Svein Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-17)
      <i>Background</i> - Maximal strength increments are reported to result in improvements in sprint speed and jump height in elite male football players. Although similar effects are expected in females, this is yet to be elucidated. The aim of this study was to examine the effect of maximal strength training on sprint speed and jump height in high-level female football players.<p> <p><i>Methods</i> ...
    • The influence of age on the match-to-match variability of physical performance in women’s elite football 

      Winther, Andreas Kjæreng; Pedersen, Sigurd; Johansen, Dag; Pettersen, Svein Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-15)
      Introduction: The fluctuation of external match load throughout a season is influenced by several contextual factors. While some, have been deeply analysed in men’s football literature, information is lacking on how other contextual elements, such as player’s age or experience, may affect the match-to-match variability of locomotor activities. In fact, aging has been described as a multifactorial ...
    • An introduction to the TACOMA distributed system. Version 1.0 

      Johansen, Dag; Renesse, Robbert van; Schneider, Fred B. (Research report; Forskningsrapport, 1995-06)
      This report briefly introduces TACOMA Version 1.0. This distributed system supports agents, computations that can roam the internet. The report presents the TACOMA project, the computational model, how to get started, and the basic TACOMA abstractions.