Recent additions

  • Predicting Transaction Latency with Deep Learning in Proof-of-Work Blockchains 

    Tedeschi, Enrico; Nordmo, Tor-Arne Schmidt; Johansen, Dag; Johansen, Håvard D. (Peer reviewed; Chapter, 2019)
    Proof-of-work based cryptocurrencies, like Bitcoin, have a fee market where transactions are included in the blockchain according to a first-price auction for block space. Many attempts have been made to adjust and predict the fee volatility, but even well-formed transactions sometimes experience delays and evictions unless an enormous fee is paid. % In this paper, we present a novel ...
  • Cloudless Friend-to-Friend Middleware for Smartphones 

    Arnes, Jo Inge; Karlsen, Randi (Peer reviewed; Chapter; Bokkapittel, 2019-11-13)
    Using smartphones for peer-to-peer communication over the Internet is difficult without the aid of centralized services. These centralized services, which usually reside in the cloud, are necessary for brokering communication between peers, and all communication must pass through them. A reason for this is that smartphones lack publicly reachable IP addresses. Also, because people carry their ...
  • Efficient concurrent search trees using portable fine-grained locality 

    Ha, Hoai Phuong; Anshus, Otto; Umar, Ibrahim (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-14)
    Concurrent search trees are crucial data abstractions widely used in many important systems such as databases, file systems and data storage. Like other fundamental abstractions for energy-efficient computing, concurrent search trees should support both high concurrency and fine-grained data locality in a platform-independent manner. However, existing portable fine-grained locality-aware search trees ...
  • Vitamin D in relation to incident sarcopenia and changes in muscle parameters among older adults: The KORA-Age Study 

    Conzade, Romy; Grill, Eva; Bischoff-Ferrari, Heike A.; Ferrari, Uta; Horsch, Alexander; Peters, Annette; Thorand, Barbara (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-08)
    Summary We report low baseline 25-hydroxyvitamin D (25OHD) levels being associated with unfavorable changes in muscle mass and physical performance over three years, but not with incident sarcopenia. Future prospective studies are needed to assess causality and to address the issue of competing risks such as mortality in older cohorts. Introduction Effects of low serum 25-hydroxyvitamin D (25OHD) ...
  • SoCodeCNN: Program Source Code for Visual CNN Classification Using Computer Vision Methodology 

    Dey, Somdip; Singh, Amit Kumar; Prasad, Dilip K.; McDonald-Maier, Klaus D. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-24)
    Automated feature extraction from program source-code such that proper computing resources could be allocated to the program is very difficult given the current state of technology. Therefore, conventional methods call for skilled human intervention in order to achieve the task of feature extraction from programs. This research is the first to propose a novel human-inspired approach to automatically ...
  • Positional Differences in Peak- and Accumulated- Training Load Relative to Match Load in Elite Football 

    Baptista, Ivan; Johansen, Dag; Figueiredo, Pedro; Rebelo, Antonio; Pettersen, Svein Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-23)
    Quantification of training and match load is an important method to personalize the training stimulus’ prescription to players according to their match demands. The present study used time-motion analysis and triaxial-accelerometer to quantify and compare: a) The most demanding passages of play in training sessions and matches (5-min peaks); b) and the accumulated load of typical microcycles and ...
  • 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 ...
  • Performance of data enhancements and training optimization for neural network: A polyp detection case study 

    Henriksen, Fredrik Lund; Jensen, Rune; Stensland, Håkon Kvale; Johansen, Dag; Riegler, Michael; Halvorsen, Pål (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-05)
    Deep learning using neural networks is becoming more and more popular. It is frequently used in areas like video analysis, image retrieval, traffic forecast and speech recognition. In this respect, the learning and training process usually requires a lot of data. However, in many areas, data is scarce which is definitely the case in our medical application scenario, i.e., polyp detection in the ...
  • Data-driven modeling and prediction of blood glucose dynamics: Machine learning applications in type 1 diabetes 

    Woldaregay, Ashenafi Zebene; Årsand, Eirik; Walderhaug, Ståle; Albers, David; Mamykina, Lena; Botsis, Taxiarchis; Hartvigsen, Gunnar (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-26)
    <i>Background</i>: Diabetes mellitus (DM) is a metabolic disorder that causes abnormal blood glucose (BG) regulation that might result in short and long-term health complications and even death if not properly managed. Currently, there is no cure for diabetes. However, self-management of the disease, especially keeping BG in the recommended range, is central to the treatment. This includes actively ...
  • Novel secure VPN architectures for LTE backhaul networks 

    Liyanage, Madhusanka; Kumar, Pradeep; Ylianttila, Mika; Gurtov, Andrei (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-11)
    In this paper, we propose two secure virtual private network architectures for the long‐term evolution backhaul network. They are layer 3 Internet protocol (IP) security virtual private network architectures based on Internet key exchange version 2 mobility and multihoming protocol and host identity protocol. Both architectures satisfy a complete set of 3GPP backhaul security requirements such as ...
  • pVD - Personal Video Distribution 

    Su, Fei; Bjørndalen, John Markus; Ha, Hoai Phuong; Anshus, Otto (Journal article; Tidsskriftartikkel; Conference object; Konferansebidrag, 2013-11-25)
    A user has several personal computers, including mobile phones, tablets, and laptops, and needs to watch live camera feeds from and videos stored at any of these computers at one or more of the others. Industry solutions designed for many users, computers, and videos can be complicated and slow to apply. The user must typically rely on a third party service or at least log in. The Personal Video ...
  • MultiStage: Acting across Distance 

    Su, Fei; Tartari, Giacomo; Bjørndalen, John Markus; Ha, Hoai Phuong; Anshus, Otto (Conference object; Konferansebidrag, 2013)
    We report on a prototype system helping actors on a stage to interact and perform with actors on other stages as if they were on the same stage. At each stage four 3D cameras tiled back to back for an almost 360 degree view, continuously record actors. The system processes the recorded data on-the-fly to discover actions by actors that it should react to, and it streams data about actors and their ...
  • Masking the Effects of Delays in Human-to-Human Remote Interaction 

    Su, Fei; Bjørndalen, John Markus; Ha, Hoai Phuong; Anshus, Otto (Chapter; Bokkapittel, 2014)
    Humans can interact remotely with each other through computers. Systems supporting this include teleconferencing, games and virtual environments. There are delays from when a human does an action until it is reflected remotely. When delays are too large, they will result in inconsistencies in what the state of the interaction is as seen by each participant. The delays can be reduced, but they cannot ...
  • Wearable Sensors with Possibilities for Data Exchange: Analyzing Statusand Needs of Different Actors in Mobile Health Monitoring Systems 

    Muzny, Miroslav; Henriksen, André; Giordanengo, Alain; Mužík, Jan; Grøttland, Astrid; Blixgård, Håvard Kvalvåg; Hartvigsen, Gunnar; Årsand, Eirik (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-31)
    <i>Background</i> - Wearable devices with an ability to collect various type of physiological data are increasingly becoming seamlessly integrated into everyday life of people. In the area of electronic health (eHealth), many of these devices provide remote transfer of health data, as a result of the increasing need for ambulatory monitoring of patients. This has a potential to reduce the cost ...
  • Data-driven blood glucose pattern classification and anomalies detection: Machine-learning applications in Type 1 diabetes 

    Woldaregay, Ashenafi Zebene; Årsand, Eirik; Botsis, Taxiarchis; Albers, David; Mamykina, Lena; Hartvigsen, Gunnar (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-01)
    <p><i>Background - </i>Diabetes mellitus is a chronic metabolic disorder that results in abnormal blood glucose (BG) regulations. The BG level is preferably maintained close to normality through self-management practices, which involves actively tracking BG levels and taking proper actions including adjusting diet and insulin medications. BG anomalies could be defined as any undesirable reading ...
  • Reproduction study using public data of: Development and validation of a deep learning algorithm for detection of diabetic retinopathy in retinal fundus photographs 

    Voets, Mike; Møllersen, Kajsa; Bongo, Lars Ailo (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-06)
    We have attempted to reproduce the results in <i>Development and validation of a deep learning algorithm for detection of diabetic retinopathy in retinal fundus photographs</i>, published in JAMA 2016; 316(22), using publicly available data sets. We re-implemented the main method in the original study since the source code is not available. The original study used non-public fundus images from EyePACS ...
  • Recommendations with a Nudge 

    Karlsen, Randi; Andersen, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-13)
    In areas such as health, environment, and energy consumption, there is a need to do better. A common goal in society is to get people to behave in ways that are sustainable for the environment or support a healthier lifestyle. Nudging is a term known from economics and political theory, for influencing decisions and behavior using suggestions, positive reinforcement, and other non-coercive means. ...
  • Convolutional Neural Network for Breathing Phase Detection in Lung Sounds 

    Jacome, Cristina; Ravn, Johan; Holsbø, Einar; Aviles-Solis, Juan Carlos; Melbye, Hasse; Ailo Bongo, Lars (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-15)
    We applied deep learning to create an algorithm for breathing phase detection in lung sound recordings, and we compared the breathing phases detected by the algorithm and manually annotated by two experienced lung sound researchers. Our algorithm uses a convolutional neural network with spectrograms as the features, removing the need to specify features explicitly. We trained and evaluated the ...
  • 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> ...
  • Performance optimization and modeling of fine-grained irregular communication in UPC 

    Lagraviere, Jeremie Alexandre Emilien; Langguth, Johannes; Prugger, Martina; Einkemmer, Lukas; Ha, Hoai Phuong; Cai, Xing (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-03)
    The Unified Parallel C (UPC) programming language offers parallelism via logically partitioned shared memory, which typically spans physically disjoint memory subsystems. One convenient feature of UPC is its ability to automatically execute between-thread data movement, such that the entire content of a shared data array appears to be freely accessible by all the threads. The programmer friendliness, ...

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