Viser treff 230-249 av 389

    • Omni-Kernel: An Operating System Architecture for Pervasive Monitoring and Scheduling 

      Kvalnes, Åge; Johansen, Dag; Renesse, Robbert van; Schneider, Fred B.; Valvåg, Steffen (Research report; Forskningsrapport, 2013)
      Clouds commonly employ virtual machine technology to leverage and efficiently utilize computational resources in data centers. The workloads encapsulated by virtual machines contend for the resources of their hosting machines, and interference from resource sharing can cause unpredictable performance. Despite the use of virtual machine technology, the role of the operating system as an arbiter of ...
    • On Edge Cloud Service Provision with Distributed Home Servers 

      Khan, Muhammed Amin; Freitag, Felix (Conference object; Konferansebidrag, 2017-12-28)
      Edge computing has been proposed for new types of cloud services, which need computing infrastructure at the network edge. Driven by important use cases from the Internet of Things (IoT) domain, edge cloud computing has also a huge business potential. Edge computing devices are already operational in many industrial and consumer-oriented scenarios. A typical characteristic of these solutions is, ...
    • On evaluation metrics for medical applications of artificial intelligence 

      Hicks, Steven A.; Strumke, Inga; Thambawita, Vajira L B; Hammou, Malek; Riegler, Michael Alexander; Halvorsen, Pål (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-08)
      Clinicians and software developers need to understand how proposed machine learning (ML) models could improve patient care. No single metric captures all the desirable properties of a model, which is why several metrics are typically reported to summarize a model’s performance. Unfortunately, these measures are not easily understandable by many clinicians. Moreover, comparison of models across studies ...
    • On Optimizing Transaction Fees in Bitcoin using AI: Investigation on Miners Inclusion Pattern 

      Tedeschi, Enrico; Nordmo, Tor-Arne Schmidt; Johansen, Dag; Johansen, Håvard D. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-09)
      The transaction-rate bottleneck built into popular proof-of-work-based cryptocurrencies, like Bitcoin and Ethereum, leads to fee markets where transactions are included 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 unexpected delays and evictions unless a substantial ...
    • On the design and performance of the PARFUM Parallel Fault Tolerant Volume Renderer 

      Asplin, Jo; Mehus, Sindre (Research report; Forskningsrapport, 1997-01)
      Volume rendering is an important and CPU-intensive technique for visualizing large scalar fields. In essence, a volume renderer performs two activites on behalf of the user: loading a new data set, and rendering the current one. At one level, the performance of an individual activity is important. At another level, the erformance of the session as a whole, in particular switching from one activity ...
    • On the design of a generic object adaptor 

      Eliassen, Frank; Hanssen, Øyvind (Conference object; Konferansebidrag, 1995-08)
    • On the performance and energy efficiency of the PGAS programming model on multicore architectures 

      Lagraviere, Jeremie Alexandre Emilien; Langguth, Johannes; Sourouri, Mohammed; Ha, Hoai Phuong; Cai, Xing (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-15)
    • Opportunities for thermal energy storage in Longyearbyen 

      van Greevenbroek, Koen; Klein, Lars-Stephan (Research report; Forskningsrapport, 2021-07-02)
      Energy storage is needed in Longyearbyen to enable a transition to local renewable energy sources. As heating accounts for more than half the energy use in Longyearbyen, affordable large-scale thermal storage is a good option. We investigate the opportunities for hot water, molten salt and hot rocks storage systems using a techno-economic optimisation model for the Longyearbyen energy system.
    • Pedagogical Perspectives of Interdisciplinary Teaching and Research: An Energy System Modelling Outlook in Relation to Energy Informatics 

      Bordin, Chiara; Mishra, Sambeet; Benth, Fred Espen (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-02)
      The purpose of this paper is to present and discuss pedagogical frameworks and approaches to developing, delivering, and evaluating a new interdisciplinary course within the domain of energy informatics at both Master’s and PhD levels. This study is needed because many papers on sustainable energy engineering education concentrate on course content but provide very little information on the ...
    • Performance experiments with the Storm View Distributed Parallel Volume Renderer. 

      Asplin, Jo; Johansen, Dag (Research report; Forskningsrapport, 1995-06)
      Volume rendering is a useful but cpu-intensive method for visualizing large scalar fields. The time to render a single image may be reduced by parallel processing. This paper reports on performance experiments with the StormView volume renderer, which is parallelized on a set of 57 MIPS / 17 MFLOPS workstations connected by a 10 Mbps Ethernet. For certain user patterns, we show that our parallelization ...
    • Performance isolation and adaption in the Vortex Kernel 

      Kvalnes, Aage; Renesse, Robbert van; Johansen, Dag (Research report; Forskningsrapport, 2003-01-10)
      Vortex is a new multiprocessor operating system kernel intended for emerging Internet service applications. The architecture is based on SEDA's staged computational model. Vortex provides mechanisms for performance isolation and dynamic adaptation. Performance results validate that the resource control mechanisms of Vortex are effective, and that Vortex significantly outperforms Linux on single-threaded ...
    • 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 ...
    • 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, ...
    • Performance principles for trusted computing with intel SGX 

      Gjerdrum, Anders Tungeland; Pettersen, Robert; Johansen, Håvard D.; Johansen, Dag (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-14)
      Cloud providers offering Software-as-a-Service (SaaS) are increasingly being trusted by customers to store sensitive data. Companies often monetize such personal data through curation and analysis, providing customers with personalized application experiences and targeted advertisements. Personal data is often accompanied by strict privacy and security policies, requiring data processing to be ...
    • Pesto flavoured security 

      Dillema, Feike W.; Stabell-Kulø, Tage (Research report; Forskningsrapport, 2002-05)
      Pesto aims at providing highly available and secure storage for longlived data to mobile users roaming into untrusted environments. Security in Pesto encompasses the following three aspects: availability, safety, and privacy. A mechanism supporting one aspect may adversely affect another. For example, replication may increase availability but complicates supporting confidentiality, and simply ...
    • The Pesto project. Goals and motivation 

      Dillema, Feike W.; Stabell-Kulø, Tage (Research report; Forskningsrapport, 2001-06)
      Pesto is a storage system geared towards a computing model where private machines play a pivotal role. Sharing of data is crucial, both between partners, and between the many devices owned by individual users. Replication is the only sensible means to provide ubiquitous access to private data. However, without provisions, replication endangers privacy by enlarging the Trusted Computing Base. The ...
    • Photoperiod-dependent developmental reprogramming of the transcriptional response to seawater entry in Atlantic salmon (Salmo salar) 

      Iversen, Marianne; Mulugeta, Teshome Dagne; West, Alexander Christopher; Jørgensen, Even Hjalmar; Martin, Samuel A. M.; Sandve, Simen Rød; Hazlerigg, David (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-12)
      The developmental transition of juvenile salmon from a freshwater resident morph (parr) to a seawater (SW) migratory morph (smolt), known as smoltification, entails a reorganization of gill function to cope with the altered water environment. Recently, we used RNAseq to characterize the breadth of transcriptional change which takes place in the gill in the FW phase of smoltification. This highlighted ...
    • Physicians Interrupted by Mobile Devices in Hospitals: Understanding the Interaction Between Devices, Roles, and Duties 

      Solvoll, Terje; Scholl, Jeremiah; Hartvigsen, Gunnar (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      A common denominator of modern hospitals is a variety of communication problems. In particular, interruptions from mobile communication devices are a cause of great concern for many physicians. Objective: To characterize how interruptions from mobile devices disturb physicians in their daily work. The gathered knowledge will be subsequently used as input for the design and development of a ...
    • Physics-Guided Loss Functions Improve Deep Learning Performance in Inverse Scattering 

      Liu, Zicheng; Roy, Mayank; Prasad, Dilip K.; Agarwal, Krishna (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-15)
      Solving electromagnetic inverse scattering problems (ISPs) is challenging due to the intrinsic nonlinearity, ill-posedness, and expensive computational cost. Recently, deep neural network (DNN) techniques have been successfully applied on ISPs and shown potential of superior imaging over conventional methods. In this paper, we discuss techniques for effective incorporation of important physical ...
    • Polar Vantage and Oura Physical Activity and Sleep Trackers: Validation and Comparison Study 

      Henriksen, André; Grimsgaard, Sameline; Hartvigsen, Gunnar; Hopstock, Laila Arnesdatter (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-27)
      Background: Consumer-based activity trackers are increasingly used in research, as they have the potential to promote increased physical activity and can be used for estimating physical activity among participants. However, the accuracy of newer consumer-based devices is mostly unknown, and validation studies are needed.<p> <p>Objective: The objective of this study was to compare the Polar Vantage ...