Sökning: "multicriteria optimization"

Hittade 5 avhandlingar innehållade orden multicriteria optimization.

  1. 1. Multicriteria optimization for managing tradeoffs in radiation therapy treatment planning

    Författare :Rasmus Bokrantz; Anders Forsgren; Karl-Heinz Küfer; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Optimization; multicriteria optimization; robust optimization; Pareto optimality; Pareto surface approximation; Pareto surface navigation; intensity-modulated radiation therapy; volumetric-modulated arc therapy; intensity-modulated proton therapy; Optimering; flermålsoptimering; robust optimering; Paretooptimalitet; Paretofrontsapproximation; Paretofrontsnavigering; intensitetsmodulerad strålterapi; rotationsterapi; intensitetsmodulerad protonterapi;

    Sammanfattning : Treatment planning for radiation therapy inherently involves tradeoffs, such as between tumor control and normal tissue sparing, between time-efficiency and dose quality, and between nominal plan quality and robustness. The purpose of this thesis is to develop methods that can facilitate decision making related to such tradeoffs. LÄS MER

  2. 2. Robust optimization of radiation therapy accounting for geometric uncertainty

    Författare :Albin Fredriksson; Anders Forsgren; Timothy C. Y. Chan; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Optimization; intensity-modulated proton therapy; uncertainty; robust planning; setup error; range error; intensity-modulated radiation therapy; multicriteria optimization;

    Sammanfattning : Geometric errors may compromise the quality of radiation therapy treatments. Optimization methods that account for errors can reduce their effects.The first paper of this thesis introduces minimax optimization to account for systematic range and setup errors in intensity-modulated proton therapy. LÄS MER

  3. 3. Copula-based Portfolio Optimization

    Författare :Maziar Sahamkhadam; Andreas Stephan; Håkan Locking; Ranadeva Jayasekera; Linnéuniversitetet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Copula; portfolio optimization; conditional Value-at-Risk; vine copulas; asymmetric tail dependence; Black-Litterman approach; expectile Value-at-Risk; multiobjective portfolios; Business administration; Företagsekonomi;

    Sammanfattning : This thesis studies and develops copula-based portfolio optimization. The overall purpose is to clarify the effects of copula modeling for portfolio allocation andsuggest novel approaches for copula-based optimization. The thesis is a compilation of five papers. LÄS MER

  4. 4. Probabilistic machine learning methods for automated radiation therapy treatment planning

    Författare :Tianfang Zhang; Jimmy Olsson; Steve Jiang; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Matematisk statistik; Mathematical Statistics;

    Sammanfattning : In this thesis, different parts of an automated process for radiation therapy treatment planning are investigated from a mathematical and computational perspective. Whereas traditional inverse planning is labor-intensive, often comprising several reiterations between treatment planner and physician before a plan can be approved, much of recent research have been aimed at using a data-driven approach by learning from historically delivered plans. LÄS MER

  5. 5. Model-based design of haptic devices

    Författare :Ahmad Aftab; Kjell Andersson; Ulf Sellgren; Per Wennhage; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Haptic device; model-based design; stiffness; SRA - ICT; SRA - Informations- och kommunikationsteknik;

    Sammanfattning : Efficient engineering design and development of high precision and reliable surgical simulators, like haptic devices for surgical training benefits from model-based and simulation driven design. The complexity of the design space, multi-domains, multicriteria requirements and multi-physics character of the behavior of such a product ask for a model based systematic approach for creating and validating compact and computationally efficient simulation models to be used for the design process. LÄS MER