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
Brief Announcement : (1+)-Approximate Shortest Paths in Dynamic Streams.
(Association for Computing Machinery, 2022-07-21) Elkin, Michael; Trehan, Chhaya; Department of Computer Science
Computing approximate shortest paths in the dynamic streaming setting is a fundamental challenge that has been intensively studied. Currently existing solutions for this problem either build a sparse multiplicative spanner of the input graph and compute shortest paths in the spanner offline, or compute an exact single source BFS tree. Solutions of the first type are doomed to incur a stretch-space tradeoff of 2k - 1 versus n1+1/k , for an integer parameter k. (In fact, existing solutions also incur an extra factor of 1+ in the stretch for weighted graphs, and an additional factor of logO(1) n in the space.) The only existing solution of the second type uses n1/2-O(1/k) passes over the stream (for space O(n1+1/k )), and applies only to unweighted graphs.
A Recursive Early-Stopping Phase King Protocol
(Association for Computing Machinery, 2022-07-21) Lenzen, Christoph; Sheikholeslami, Sahar; Department of Computer Science
Early-stopping consensus protocols guarantee termination within a number of rounds that depends only on the actual number f of faulty nodes in a run, not the maximum number of faults that can be tolerated. We consider early-stopping deterministic synchronous consensus with Byzantine faults in a fully connected message passing system of n nodes. Many such protocols are known, but so far none combine early-stopping in O(f+1) rounds with optimal resilience and a bit complexity of o(n2(f+1)). We provide two solutions to the above problem. The first is fairly simple and almost matches the above goals, but has worst-case message and bit complexities of Θ(n2 log (f+2)). The second reduces the bit complexity further to O(n2) by calling itself recursively at most twice on Θ(n)-sized subsets. The result is the first protocol that is simultenously optimally resilient, asymptotically optimally early-stopping, and asymptotically bit- and message-optimal.
Lockdown Duration and Training Intensity Affect Sleep Behavior in an International Sample of 1,454 Elite Athletes
(2022-06-15) Romdhani, Mohamed; Fullagar, Hugh H.K.; Vitale, Jacopo A.; Nédélec, Mathieu; Rae, Dale E.; Ammar, Achraf; Chtourou, Hamdi; Al Horani, Ramzi A.; Ben Saad, Helmi; Bragazzi, Nicola Luigi; Dönmez, Gürhan; Dergaa, Ismail; Driss, Tarak; Farooq, Abdulaziz; Hammouda, Omar; Harroum, Nesrine; Hassanmirzaei, Bahar; Khalladi, Karim; Khemila, Syrine; Mataruna-Dos-Santos, Leonardo Jose; Moussa-Chamari, Imen; Mujika, Iñigo; Muñoz Helú, Hussein; Norouzi Fashkhami, Amin; Paineiras-Domingos, Laisa Liane; Khaneghah, Mehrshad Rahbari; Saita, Yoshitomo; Souissi, Nizar; Trabelsi, Khaled; Washif, Jad Adrian; Weber, Johanna; Zmijewski, Piotr; Taylor, Lee; Garbarino, Sergio; Chamari, Karim; Department of Sport Science
Objective: To investigate the effect of 1) lockdown duration and 2) training intensity on sleep quality and insomnia symptoms in elite athletes. Methods: 1,454 elite athletes (24.1 ± 6.7 years; 42% female; 41% individual sports) from 40 countries answered a retrospective, cross-sectional, web-based questionnaire relating to their behavioral habits pre- and during- COVID-19 lockdown, including: 1) Pittsburgh sleep quality index (PSQI); 2) Insomnia severity index (ISI); bespoke questions about 3) napping; and 4) training behaviors. The association between dependent (PSQI and ISI) and independent variables (sleep, napping and training behaviors) was determined with multiple regression and is reported as semi-partial correlation coefficient squared (in percentage). Results: 15% of the sample spent < 1 month, 27% spent 1–2 months and 58% spent > 2 months in lockdown. 29% self-reported maintaining the same training intensity during-lockdown whilst 71% reduced training intensity. PSQI (4.1 ± 2.4 to 5.8 ± 3.1; mean difference (MD): 1.7; 95% confidence interval of the difference (95% CI): 1.6–1.9) and ISI (5.1 ± 4.7 to 7.7 ± 6.4; MD: 2.6; 95% CI: 2.3–2.9) scores were higher during-compared to pre-lockdown, associated (all p < 0.001) with longer sleep onset latency (PSQI: 28%; ISI: 23%), later bedtime (PSQI: 13%; ISI: 14%) and later preferred time of day to train (PSQI: 9%; ISI: 5%) during-lockdown. Those who reduced training intensity during-lockdown showed higher PSQI (p < 0.001; MD: 1.25; 95% CI: 0.87–1.63) and ISI (p < 0.001; MD: 2.5; 95% CI: 1.72–3.27) scores compared to those who maintained training intensity. Although PSQI score was not affected by the lockdown duration, ISI score was higher in athletes who spent > 2 months confined compared to those who spent < 1 month (p < 0.001; MD: 1.28; 95% CI: 0.26–2.3). Conclusion: Reducing training intensity during the COVID-19-induced lockdown was associated with lower sleep quality and higher insomnia severity in elite athletes. Lockdown duration had further disrupting effects on elite athletes’ sleep behavior. These findings could be of relevance in future lockdown or lockdown-like situations (e.g., prolonged illness, injury, and quarantine after international travel).
Flexible, Fully Printable, and Inexpensive Paper-Based Chipless Arabic Alphabet-Based RFID Tags
(2022-01-01) Yousaf, Jawad; Almajali, Eqab; El Najjar, Mahmoud; Amir, Ahmed; Altaf, Amir; Elahi, Manzoor; Alja’afreh, Saqer Saleh; Rmili, Hatem; Department of Engineering
This work presents the design and analysis of newly developed reconfigurable, flexible, inexpensive, optically-controlled, and fully printable chipless Arabic alphabet-based radio frequency identification (RFID) tags. The etching of the metallic copper tag strip is performed on a flexible simple thin paper substrate (ɛr = 2.31) backed by a metallic ground plane. The analysis of investigated tags is performed in CST MWS in the frequency range of 1–12 GHz for the determination of the unique signature resonance characteristics of each tag in terms of its back-scattered horizontal and vertical mono-static radar cross section (RCS). The analysis reflects that each tag has its own unique electromagnetic signature (EMS) due to the changing current distribution of metallic resonator. This EMS of each tag could be used for the robust detection and recognition of all realized 28 Arabic alphabet tags. The study also discusses, for the first time, the effect of the change in font type and size of realized tags on their EMS. The robustness and reliability of the obtained EMS of letter tags is confirmed by comparing the RCS results for selective letter tags using FDTD and MoM numerical methods, which shows very good agreement. The proposed tags could be used for smart internet of things (IoT) and product marketing applications.
Waste Management under Structural Constraints: Efficiency, Policy Reform, and Recycling Performance in Iceland
(University of Iceland, School of Social Sciences, Faculty of Business Administration, 2026-11-09) Óskarsson, Guðmundur Kristján; Dr. Sveinn Agnarsson; Faculty of Business Administration (UI); Viðskiptafræðideild (HÍ); School of Social Sciences (UI); Félagsvísindasvið (HÍ)
This doctoral thesis evaluates the efficiency, policy translation, and recycling performance of municipal waste management systems in Iceland, a small and geographically dispersed Arctic economy. Based on an integrated multi-method research design, the thesis examines the transition from a fragmented and structurally constrained system toward a harmonised framework underpinned by an expanded Extended Producer Responsibility (EPR) mandate and the 2023 “Circular Law.”
Rather than viewing policy implementation as a linear process, the thesis proposes that circular economy outcomes emerge through a hierarchical filtering mechanism. Combined efficiency analysis (Data Envelopment Analysis) and econometric modelling demonstrate that geographic dispersion, demographic volatility, and seasonal tourism act as binding structural constraints. What standard performance metrics often interpret as managerial inefficiency instead reflects the operational friction of Arctic logistics and systematic denominator bias.
While the 2023 reform expanded and harmonised producer-financed responsibility, municipalities retained responsibility for organising collection services. Analyses of early recovery determinants using Grey Relational and econometric approaches, together with panel Interrupted Time Series analysis of residual-waste composition, show that institutional harmonisation does not produce uniform outcomes. The rollout of the mandatory four-bin source-separation system served as a critical household-facing operational interface and was associated with a structural break in the amount of biodegradable kitchen waste remaining in the general bin. However, the magnitude of these outcomes remained conditioned by local infrastructure configuration and spatial constraints.
To synthesise these findings, the thesis develops an integrated four-level socio-technical framework. The framework shows how structural geography (Level I) filters how institutional design (Level II) is translated into operational infrastructure (Level III) and, ultimately, realised system outcomes (Level IV). The thesis concludes that in geographically heterogeneous environments, harmonised regulatory frameworks are necessary but insufficient; achieving a circular economy requires infrastructure systems that are explicitly adapted to local spatial conditions. The findings have practical relevance for the design of performance metrics, financing arrangements, and collection systems in geographically heterogeneous jurisdictions. Although developed from the Icelandic case, the analytical framework has potential transferability to other small, island, Arctic, and remote regions where common circular economy objectives must be implemented under markedly different spatial and service conditions.
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