Sökning: "Stefan Alfredsson"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden Stefan Alfredsson.

  1. 1. A Cross-Layer Perspective on Transport Protocol Performance in Wireless Networks

    Författare :Stefan Alfredsson; Anna Brunström; Christer Åhlund; Karlstads universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Wireless networks; 4G; cross-layer interaction; TCP; UDP; emulation; performance evaluation; optimizations; Computer Science; Datavetenskap;

    Sammanfattning : Communication by wireless technologies has seen a tremendous growth in the last decades. Mobile phone technology and wireless broadband solutions are rapidly replacing the last-hop wireline connectivity for telephones and Internet access. LÄS MER

  3. 2. TCP in Wireless Networks: Challenges, Optimizations and Evaluations

    Författare :Stefan Alfredsson; Anna Brunström; Lars-Åke Larzon; Karlstads universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wireless networks; TCP IP; TCP-L; Network emulation; Computer science; Datavetenskap; Computer Science; Datavetenskap;

    Sammanfattning : This thesis presents research on transport layer behavior in wireless networks. As the Internet is expanding its reach to include mobile devices, it has become apparent that some of the original design assumptions for the dominant transport protocol, TCP, are approaching their limits. LÄS MER

  4. 3. Improving the Energy Efficiency of Cellular IoT Device

    Författare :Muhammad Tahir Abbas; Karl-Johan Grinnemo; Johan Eklund; Mohammad Rajiullah; Stefan Alfredsson; Peter Sjödin; Karlstads universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CIoT; 3GPP; energy saving; mMTC; NB-IoT; LTE-M; EC-GSM- IoT; Computer Science; Datavetenskap;

    Sammanfattning : Cellular Internet of Things (CIoT) has emerged as a promising technology to support applications that generate infrequent data. One requirement on these applications, often battery-powered devices, is low energy consumption to enable extended battery life. LÄS MER

  5. 4. Churning losses and efficiency in gearboxes

    Författare :Martin Andersson; Ulf Olofsson; Stefan Björklund; Ulf Sellgren; Bo Alfredsson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; gears; efficiency; temperature; running-in; assembly; torque loss; surface roughness;

    Sammanfattning : Efficient transmissions systems are key to producing competitive motor vehicles that have a smaller environmental impact. Gears are the main components in vehicle transmissions and although they are already highly efficient, there is still room for improvement. LÄS MER

  7. 5. Initiation of rolling contact fatigue from asperities in elastohydrodynamic lubricated contacts

    Författare :Carl-Magnus Everitt; Bo Alfredsson; Stefan Björklund; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spalling; Pitting; Slip; Elastohydrodynamic; Thermal elastohydrodynamic; Fatigue; Contact mechanics.; Pitting; Glidning; Elastohydrodynamik; Termisk elastohydrodynamik; Utmattning; Kontaktmekanik.; Hållfasthetslära; Solid Mechanics;

    Sammanfattning : Rolling contacts are utilized in many technical applications, both in bearings and in the contact between gear teeth. These components are often highly loaded, which makes them susceptible to suffer from rolling contact fatigue. This work focuses on the rolling contact fatigue mechanism of pitting. LÄS MER