Sökning: "edge density"

Visar resultat 1 - 5 av 156 avhandlingar innehållade orden edge density.

  1. 1. Forest edges in boreal landscapes - factors affecting edge influence

    Författare :Ulrika Jansson; Per-Anders Esseen; Mats Nilsson; Timo Kuuluvainen; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; aerial photographs; edge contrast; edge density; edge length; fetch size; forest fragmentation; lichen growth; line intersect sampling; pendulous lichen; photo interpretation; skogskant; flygbild; kantlängd; lav; Terrestrial ecology; Terrestisk ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : The boreal forest in Fennoscandia has been subjected to major loss and fragmentation of natural forests due to intensive forestry. This has resulted in that forest edges are now abundant and important landscape features. Edges have documented effects on the structure, function and biodiversity in forests. LÄS MER

  3. 2. A Theoretical Study: The Connection between Stability of Single-Walled Carbon Nanotubes and Observed Products

    Författare :Daniel Hedman; Andreas Larsson; Sven Öberg; Krisztián Kordás; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Single-walled carbon nanotubes; density functional theory; catalytic chemical vapor deposition; chirality-specific growth; stability; length; diameter; edge; chirality; Applied Physics; Tillämpad fysik;

    Sammanfattning : Over the past 20 years’ researchers have tried to utilize the remarkable properties of single-walled carbon nanotubes (SWCNTs) to create new high-tech materials and devices, such as strong light-weight composites, efficient electrical wires and super-fast transistors. But the mass production of these materials and devices are still hampered by the poor uniformity of the produced SWCNTs. LÄS MER

  4. 3. Cluster investigations of the extent and altitude distribution of the auroral density cavity

    Författare :Love Alm; Göran T. Marklund; Tomas Karlsson; Rickard Lundin; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Auroral density cavity; auroral accelaration; Cluster; in situ observation; electron density; pseudo altitude; Physics; Fysik;

    Sammanfattning : The auroral density cavity constitutes the boundary between the cold, dense ionospheric plasma and the hot, tenuous plasma sheet plasma. The auroral density cavity is characterized by low electron density and particle populations modified by parallel electric fields. LÄS MER

  5. 4. Discrete Scale-Space Theory and the Scale-Space Primal Sketch

    Författare :Tony Lindeberg; Jan-Olof Eklundh; Jan. J Koenderink; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Computer vision; low-level processing; scale-space; diffusion; Gaussian filtering; discrete smoothing; primal sketch; segmentation; descriptive elements; scale detection; image structure; focus-of-attention; tuning low-level processing; blob detection; edge detection; edge focusing; histogram analysis; junction classification; perceptual grouping; texture analysis; critical points; classification of blob events; bifurcations; drift velocity; density of local extrema; multi-scale representation; digital signal processing; Computer Science; Datalogi;

    Sammanfattning : This thesis, within the subfield of computer science known as computer vision, deals with the use of scale-space analysis in early low-level processing of visual information. The main contributions comprise the following five subjects:The formulation of a scale-space theory for discrete signals. LÄS MER

  7. 5. Reactivity of Transition-Metal Compounds from Electronic Structure

    Författare :Aleksandra Vojvodic; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; magnetic edge states; electronic structure; density-functional theory; growth; surface states and resonances; nitrides; density of states; hydrodesulphurisation; sulphides; steam reforming; transition-metal carbides; Bronsted-Evans Polanyi relation; scaling relations; adsorption; descriptor; reactivity; catalysis;

    Sammanfattning : Transition-metal carbides (TMC's), nitrides, and sulfides belong to the class of materials known as transition-metal compounds (TMX's). Besides having intriguing properties, these materials are relevant for, e.g., growth and catalysis. LÄS MER