Search for dissertations about: "Roland Eriksson"

Showing result 1 - 5 of 18 swedish dissertations containing the words Roland Eriksson.

  2. 1. On the Ising problem and some matrix operations

    Author : Daniel Andrén; Roland Häggkvist; Henrik Eriksson; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ising problem; phase tansition; matrix multiplicatoin; matrix inversion; Discrete mathematics; Diskret matematik;

    Abstract : The first part of the dissertation concerns the Ising problem proposed to Ernst Ising by his supervisor Wilhelm Lenz in the early 20s. The Ising model, or perhaps more correctly the Lenz-Ising model, tries to capture the behaviour of phase transitions, i.e. how local rules of engagement can produce large scale behaviour. READ MORE

  4. 2. On Latin squares and avoidable arrays

    Author : Lina J. Andrén; Roland Häggkvist; Kimmo Eriksson; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Latin square; avoidability; avoidable array; Discrete mathematics; Diskret matematik; Mathematics; matematik;

    Abstract : This thesis consists of the four papers listed below and a survey of the research area. I Lina J. Andrén: Avoiding (m, m, m)-arrays of order n = 2k II Lina J. Andrén: Avoidability of random arrays III Lina J. READ MORE

  5. 3. Development of on-line diagnostic methods for medium voltage XLPE power cables

    Author : Valentinas Dubickas; Hans Edin; Roland Eriksson; Matti Lehtonen; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Elektroteknik;

    Abstract : On-line diagnostics of power system components is an important area since it allows the diagnostics to be performed at regular intervals during the normal operation of the components. This combined with reliability centered maintenance could lead to reduced customer outages. READ MORE

  6. 4. On-line time domain reflectometry diagnostics of medium voltage XLPE power cables

    Author : Valentinas Dubickas; Roland Eriksson; Tord Bengtsson; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Elektroteknik;

    Abstract : Degradation of XLPE insulated power cables by water-trees is a primary cause of failure of these cables. The detection of water-trees and information about the severity of the degradation can be obtained with off-line measurement using dielectric spectroscopy. In many situations only a limited part of the cable may be degraded by the water-trees. READ MORE

  7. 5. Modelling of cavity partial discharges at variable applied frequency

    Author : Cecilia Forssén; Roland Eriksson; Hans Edin; Peter H.F. Morshuis; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; partial discharges; measurements; modelling; variable frequency; cavities; disc-shaped; polycarbonate; Electric power engineering; Elkraftteknik;

    Abstract : The presence of partial discharges (PD) in high voltage components is generally a sign of defects and degradation in the electrical insulation. To diagnose the condition of high voltage insulation, PD measurements is commonly used. READ MORE