Opin vísindi
Opin vísindi er varðveislusafn vísindaefnis og doktorsritgerða í opnum aðgangi á vegum íslenskra háskóla og Landsbókasafns Íslands - Háskólabókasafns.
Opinn aðgangur að rannsóknaniðurstöðum er í samræmi við 10. gr. laga nr. 3/2003 um opinberan stuðning við vísindarannsóknir sem og kröfur innlendra og erlendra rannsóknasjóða. Markmiðið með opnum aðgangi er að niðurstöður rannsókna séu aðgengilegar sem flestum óhindrað og án endurgjalds á rafrænu formi. Vistun í varðveislusafninu er varanleg og ætlað að tryggja aðgang að vísindaefni íslenskra háskóla í opnum aðgangi um ókomna tíð. Varðveislusafnið Opin vísindi er tengt við rannsóknagáttina IRIS og rannsóknaniðurstöður í opnum aðgangi sem eru skráðar í IRIS eru um leið vistaðar og gerðar aðgengilegar til framtíðar í varðveislusafninu. Með því að safna þessu efni saman í eitt safn verður aðgangur að því einfaldur og þægilegur fyrir alla sem vilja kynna sér það og geta þannig notið þess öfluga vísindastarfs sem fram fer í háskólum landsins.
Varðveislusafnið er OpenAIRE / OpenAIREplus samhæft og samrýmist kröfum sem gerðar eru um birtingu rannsóknaniðurstaðna úr verkefnum sem styrkt eru úr evrópsku rannsóknaáætlununum FP7 og H2020.
Varðveislusafnið notar opna hugbúnaðinn DSpace.
Opinn aðgangur að rannsóknaniðurstöðum er í samræmi við 10. gr. laga nr. 3/2003 um opinberan stuðning við vísindarannsóknir sem og kröfur innlendra og erlendra rannsóknasjóða. Markmiðið með opnum aðgangi er að niðurstöður rannsókna séu aðgengilegar sem flestum óhindrað og án endurgjalds á rafrænu formi. Vistun í varðveislusafninu er varanleg og ætlað að tryggja aðgang að vísindaefni íslenskra háskóla í opnum aðgangi um ókomna tíð. Varðveislusafnið Opin vísindi er tengt við rannsóknagáttina IRIS og rannsóknaniðurstöður í opnum aðgangi sem eru skráðar í IRIS eru um leið vistaðar og gerðar aðgengilegar til framtíðar í varðveislusafninu. Með því að safna þessu efni saman í eitt safn verður aðgangur að því einfaldur og þægilegur fyrir alla sem vilja kynna sér það og geta þannig notið þess öfluga vísindastarfs sem fram fer í háskólum landsins.
Varðveislusafnið er OpenAIRE / OpenAIREplus samhæft og samrýmist kröfum sem gerðar eru um birtingu rannsóknaniðurstaðna úr verkefnum sem styrkt eru úr evrópsku rannsóknaáætlununum FP7 og H2020.
Varðveislusafnið notar opna hugbúnaðinn DSpace.
Nýlega bætt við
Surrogate modeling of ultrasonic nondestructive evaluation simulations
(2016) Siegler, Jacob; Leifsson, Leifur; Grandin, Robert; Koziel, Slawomir; Bekasiewicz, Adrian; Department of Engineering
Ultrasonic testing (UT) is used to detect internal flaws in materials or to characterize material properties. Computational simulations are an important part of the UT process. Fast models are essential for UT applications such as inverse design or model-assisted probability of detection. This paper presents investigations of using surrogate modeling techniques to create fast approximate models of UT simulator responses. In particular, we propose to use data-driven surrogate modeling techniques (kriging interpolation), and physics-based surrogate modeling techniques (space mapping), as well a mixture of the two approaches. These techniques are investigated for two cases involving UT simulations of metal components immersed in a water bath during the inspection process.
Expedited dimension scaling of microwave and antenna structures using inverse surrogates
(2016) Koziel, Slawomir; Bekasiewicz, Adrian; Leifsson, Leifur; Department of Engineering
Re-designing circuits for various sets of performance specifications is an important problem in microwave and antenna engineering. Unfortunately, this is a difficult task that is normally realized as a separate design process, which is often as expensive (in computational terms) as obtaining the original design. In this work, we consider the application of inverse surrogate modeling for fast geometry scaling of microwave and antenna structures. Computational efficiency of the discussed procedure is ensured by representing the structure at the low-fidelity model level. The explicit relation between design specifications (here, operating frequency) of the structure and its geometry dimensions is determined based on a set of predetermined reference designs. Subsequently, the model is corrected to elevate the redesigned geometry to the high-fidelity electromagnetic (EM) model level. Our approach is demonstrated through a compact rat-race coupler and a patch antenna with enhanced bandwidth.
Assessing neurocognitive outcomes in PTSD: a multilevel meta-analytical approach : a multilevel meta-analytical approach
(2025-12-31) Aspelund, Snaefridur Gudmundsdottir; Lorange, Hjordis Lilja; Halldorsdottir, Thorhildur; Baldursdottir, Birna; Valdimarsdottir, Heiddis; Valdimarsdottir, Unnur; Jónsdóttir, Harpa Lind Hjördísar; Sálfræðideild
Background: Evidence supporting the association between posttraumatic stress disorder (PTSD) and cognitive impairment is accumulating. However, less is known about which factors influence this association. Objective: The aims of this meta-analysis were to (1) elucidate the association between PTSD and a broad spectrum of cognitive impairment, including the risk of developing neurocognitive disorder (NCD) later in life, using a multilevel meta-analytic approach, and (2) identify potential moderating factors of this association by examining the effects of age (20–39, 40–59, 60+), study design (cross-sectional or longitudinal), study population (war-exposed populations/veterans or the general population), neurocognitive outcome assessed (i.e. a diagnosis of NCD or type of cognitive domain as classified according to A Compendium of Neuropsychological tests), gender (≥50% women or <50% women), study quality (high vs low), type of PTSD measure (self-report or clinical diagnosis), as well as the presence of comorbidities such as traumatic brain injury (TBI), depression, and substance use (all coded as either present or absent). Method: Peer-reviewed studies on this topic were extracted from PubMed and Web of Science with predetermined keywords and criteria. In total, 53 articles met the criteria. Hedge‘s g effect sizes were calculated for each study and a three-level random effect meta-analysis conducted. Results: After accounting for publication bias, the results suggested a significant association between PTSD and cognitive impairment, g = 0.13 (95% CI: 0.10–0.17), indicating a small effect. This association was consistent across all examined moderators, including various neurocognitive outcomes, age, gender, study design, study population, study quality, type of PTSD measure, and comorbidities such as depression, substance use, and TBI. Conclusions: These findings collectively suggest that PTSD is associated with both cognitive impairment and NCD. This emphasizes the need for early intervention (including prevention strategies) of PTSD, alongside monitoring cognitive function in affected individuals. International Prospective Register of Systematic Reviews (PROSPERO) registration number: CRD42021219189, date of registration: 02.01.2021.
Youth mental health crisis: A translational view of the COVID-19 pandemic : A translational view of the COVID-19 pandemic
(2025-07) Halldorsdottir, Thorhildur; Sálfræðideild
Mental health problems among children and adolescents have increased over the past two decades, a trend that was further exacerbated by the COVID-19 pandemic. To improve prevention and treatment strategies, developmentally informed and data-driven multidisciplinary approaches are urgently needed to clarify the mechanisms underlying youth vulnerability and resilience. Stress and trauma exposure are among the strongest predictors of youth mental health problems; however, most children and adolescents remain resilient despite such exposures. The widespread and heterogeneous challenges posed by the COVID-19 pandemic offer a unique opportunity to examine, at scale, who develops mental health problems under stress and who remains resilient. Integrating emerging findings on pandemic-related risk and protective factors with evidence from animal models can illuminate sensitive developmental periods of heightened susceptibility to environmental influence and biological embedding. This approach can identify when, how, and through what pathways mental health problems emerge, including gene–environment interactions and epigenetic mechanisms. Such knowledge will inform both behavioral and pharmacological interventions, pinpointing not only specific treatment targets but also the optimal timing for intervention to be the most effective.
Approximations of unbounded convex projections and unbounded convex sets
(2025-04) Kováčová, Gabriela; Rudloff, Birgit; Department of Engineering
We consider the problem of projecting a convex set onto a subspace or, equivalently formulated, the problem of computing a set obtained by applying a linear mapping to a convex feasible set. This includes the problem of approximating convex sets by polyhedrons. The existing literature on convex projections provides methods for bounded convex sets only, in this paper we propose a method that can handle both bounded and unbounded problems. The algorithms we propose build on the ideas of inner and outer approximation. In particular, we adapt the recently proposed methods for solving unbounded convex vector optimization problems to handle also the class of projection problems.
Flokkar í Opnum vísindum
Veldu flokk til að skoða.
- University of Iceland
- University of Akureyri
- Bifröst University
- Hólar University College
- IRIS
- Agricultural University of Iceland
- National and University Library of Iceland
- Iceland University of the Arts