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
Lower bounds for on-line graph coloring
(1994-08-01) Halldórsson, Magnus M.; Szegedy, Mario; Department of Computer Science
An algorithm for vertex-coloring graphs is said to be on-line if each vertex is irrevocably assigned a color before later vertices are considered. We show that for every such algorithm there exists a log n-colorable graph for which the algorithm uses at least 2n/log n colors. This also holds for randomized algorithms, to within a constant factor, against an oblivious adversary. We then show that various means of relaxing the constraints of the on-line model do not reduce these lower bounds. The features include presenting the input in blocks of up to log2 n vertices, recoloring any fraction of the vertices, presorting vertices by degree, and disclosing the adversary's previous coloring.
Greed is good : Approximating independent sets in sparse and bounded-degree graphs
(Association for Computing Machinery, 1994-05-23) Halldórsson, Magnús M.; Radhakrishnam, Jaikumar; Department of Computer Science
The minimum- degree Greedy algorithm, or Greedy for short, is one of the implest, most efficient, and most thoroughly studied methods for finding independent sets in graphs. We show that it surprisingly achieves a performance ratio of (Δ+ 2)/3 for approximating independent sets in graphs with degree bounded by A. The analysis directs us towards a simple parallel and distributed algorithm with identical performance, which on constant-degree graphs runs in O(log" n) time using linear number of processors. We also analyze the Greedy algorithm when run in combination with a fractional relaxation technique of Nemhauser and Trotter, and obtain an improved (2Z + 3)/5 performance ratio on graphs with average degree . Finally, we introduce a generally applicable technique for improving the approximation ratios of independent set algorithms, and illustrate it by improving the performance ratio of Greedy for large Δ.
Choosing not to see : Visual inattention as a method of information avoidance
(2024-11) Børsting, Caroline Kjær; Batuev, Aleksandr; Shalvi, Shaul; Orquin, Jacob Lund; Department of Business and Economics
People rely on a number of methods to avoid information that would compel them to change their beliefs or behaviors. However, it remains unclear whether people use visual inattention as a method of information avoidance. In three eye-tracking experiments, we test the hypothesis that people avoid visual information by strategically suppressing and facilitating visual attention depending on where desired and avoided information is likely to appear. Introducing a novel search task, we independently manipulate the probability of where desired and avoided information appear on the screen. Study 1 show that participants learn statistical regularities in information location and utilize this to gradually suppress attention to undesired information. Study 2 and 3 show that participants can simultaneously reduce and increase visual attention to areas where avoided and desired information are most likely to appear. The findings point to suppression of attention as a mechanism behind information avoidance through visual inattention and that reducing the predictability of where information appears could be a fruitful avenue for reducing it.
Cognitive Behavioral Therapy for Paroxysmal Atrial Fibrillation : Heart Rate Variability, Physical Activity, and Sleep
(2024-11) Skúladóttir, H.; Särnholm, J.; Ólafsdóttir, E.; Arnardóttir, E. S.; Hoppe, K.; Bottai, M.; Ljótsson, B.; Braunschweig, F.; Department of Engineering
Background: Cognitive behavioral therapy for symptom preoccupation in paroxysmal atrial fibrillation (AF-CBT) significantly improved AF-specific quality of life in a recent trial. To what extent this may this may be associated with changes in physiological parameters is yet to be determined. Objectives: The purpose of this study was to assess the effects of AF-CBT on heart rate variability (HRV), physical activity, and sleep. Methods: Patients with symptomatic paroxysmal AF on optimal medical therapy (mean ± standard deviation 65.4 ± 8.3 years, 58% females, 61% on beta-blockers) were randomized to a 10-week online AF-CBT (n = 65) or AF education (n = 62). AF-CBT was therapist-led and focused on social and physical avoidance. A 5-day Patch-Holter with an integrated accelerometer was applied at baseline, post-treatment, and at 3-month follow-up to assess AF burden, HRV, physical activity, and sleep duration. Subjective assessments were made by the International Physical Activity (IPAQ) and Insomnia Severity Index questionnaires. Results: At baseline, participants walked on average 8040 ± 2600 steps/day and slept 8.0 ± 1.1 hours. Objective and subjective physical activity and sleep duration remained unchanged after treatment, with no significant difference between the groups. The Insomnia Severity Index score went from subclinical insomnia (12.2 ± 6.7) to near normal values (8.1 ± 5.6), a significant change compared to controls (P = 0.032). No changes were found in AF burden or HRV indices at rest during the day or at night. Conclusions: In this select cohort, AF-CBT decreased insomnia severity but had no impact on HRV or physical activity. Thus, AF-CBT may operate through psychological and behavioral factors that are not targeted by current medical and lifestyle interventions.
Beyond School Climate : Validating the School as a Protective Factor-Brief Survey
(2024-11) Lilly, Christa L.; Kristjansson, Alfgeir L.; Smith, Megan L.; Thrisdottir, Inibjorg Eva; Havlicak, Ashley; Mann, Michael J.; Department of Psychology
BACKGROUND: The conceptual framework for School as a Protective Factor approach was presented in a companion article in this issue of the journal. The current article describes the validation of the School as a Protective Factor-Brief (SPF-Brief), a 13-item survey measuring the 3 core constructs and 13 defining characteristics of this framework. METHODS: The SPF-Brief was validated through 2 studies. The developmental study used a longitudinal design including 1349 participants who completed surveys over 5 semesters, while the validation study used a cross-sectional design with 2775 participants. Both studies included middle and high school students. Factor analysis, growth model analysis, criterion-related validation, and outcome analysis were employed. RESULTS: Analyses provided strong evidence supporting the reliability and validity of the instrument and conceptual framework. Higher SPF-Brief scores were associated with higher math grades, English grades, and quality of life, as well as lower rates of anxiety, depression, conduct disorder, alcohol, e-cigarette, tobacco, and cannabis use. Effect size estimates ranged from moderate to strong. CONCLUSIONS: These findings suggest the utility of the SPF-Brief instrument and the School as a Protective Factor framework. Together, they may offer advantages to the traditional school climate approach.
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