Opin vísindi

 

Nýlega bætt við

Verk
Multi-fidelity design optimization of transonic airfoils using shape-preserving response prediction
(2010) Leifsson, Leifur; Koziel, Slawomir; Department of Engineering
A computationally efficient methodology for transonic airfoil design optimization is presented. Our approach exploits a corrected physics-based low-fidelity surrogate that replaces, in the optimization process, an accurate but computationally expensive high-fidelity airfoil model. Correction of the low-fidelity model is achieved by aligning its corresponding airfoil surface pressure distributions with that of the high-fidelity model using a shape-preserving response prediction technique. The presented method is applied to airfoil lift maximization in two-dimensional inviscid transonic flow, subject to constraints on shock induced pressure drag and airfoil cross-sectional area. More than a 90% reduction in high-fidelity function calls is achieved when compared to direct high-fidelity model optimization.
Verk
Computational optimization, modelling and simulation - A paradigm shift
(2010) Yang, Xin She; Koziel, Slawomir; Department of Engineering
Computational optimization forms an integrated part of modern computational science. Any good design should intend to achieve certain optimality, though optimal solutions are often difficult to find in practice since uncertainty and nonlinearity always present in almost all real-world problems. As resources, time and money are always limited, optimization becomes even more important in practice. This workshop on Computational Optimization, Modelling and Simulation (COMS 2010) at ICCS 2010 will summarize the latest developments of optimization and modelling and their applications in science, engineering and industry.
Verk
Municipal amalgamations and local housing prices
(2022-01-26) Karlsson, Vífill; Eythórsson, Grétar Thór; Faculty of Business Administration
In this paper, we examine the relationship between housing prices and municipal amalgamations. Due to consumer preference for access over amenity value, there is a spatial disparity of housing prices, refiecting the value of land in specific locations. According to Tiebout (1956) local amenity values will increase if the services of a municipality improve without a comparable rise in taxes or service fees, or if taxes or service fees decrease while the service level remains the same. The bid-rent curve is a framework frequently used to capture a presence of goods or bads such as amenities, disamenities, and externalities. Accordingly, the present study will be used to detect a possible social benefit or loss following amalgamations of municipalities. Macro panel data from Iceland will be used, representing several essential variables of the house market for 79 municipalities in Iceland during the period from 1992 through 2006. The research shows a significant positive relationship, ceteris paribus, between regional municipal amalgamations and local real prices of apartments.
Verk
Digitalization and remote work in peripheral labour markets in the Nordic region
(2026-08) Eythórsson, Grétar Thór; Jóhannesson, Hjalti; Faculty of Business Administration
This article explores the impact of technological transformation as one of the global megatrends in modern times. We focus on how new technologies, especially digitalization, have made it possible for people in peripheral places to work remotely. The focus is on the case municipalities in Iceland, especially Húsavík in in Norðurþing in northern Iceland, but also in a comparative context with remote municipalities in Norway, Sweden, and Åland. The empirical data used is from the Nordic project SUNREM (Sustainable Nordic Remote Labour Markets), which has been studying the impacts of megatrends on the sustainability of remote labour markets in four Nordic countries. Data is collected from in-depth interviews with stakeholders, policymakers, and ordinary citizens in seven selected cases in the four countries. The key research questions dealt with here are: What is the situation of remote work in selected cases in Nordic sparsely populated areas? What preconditions are needed for remote digital working? Has remote work made the labour market more sustainable? The main conclusions are that remote working exists in all of the Nordic cases investigated. The town of Húsavík in the municipality of Norðurþing in North Iceland, stands out with its well-developed remote work centres. There are clear signs that facilities where people can work and meet other remote workers are important. This enables broader recruitment into the labour market, since for example spouses can use this option, enabling them to move to more remote places. Remote work from people's homes has some disadvantages, as pointed out by various researchers, and therefore infrastructure for remote working contributes to making labour markets in the periphery more sustainable.
Verk
Fluid-rock interaction in the vicinity of felsic and mafic intrusions
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Earth Sciences, 2026-11-13) Pilicita Masabanda, Byron Fabian; Enikő Bali; Faculty of Earth Sciences (UI); Jarðvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)
This research deals with the thermal and geochemical evolution of the magmatic-hydrothermal transition within the Geitafell Central Volcano (GCV), SE Iceland, to provide critical insights for high-temperature geothermal exploration. By integrating petrography, bulk-rock geochemistry, micro-analytical techniques, and thermal modeling, this study establishes a framework for understanding how intrusions of different sizes drive high-enthalpy systems. The study reveals that geothermal maturation is sustained by a suite of heat sources. Small-scale basaltic dikes (0.5 m thick) generate high-temperature pulses, inducing localized cryptic partial melting (3–10%) and high-grade metamorphism (>800 °C). Although these dikes solidify in less than a day, their thermal impact elevates host-rock temperatures for up to three years; therefore, frequent injections maintain elevated temperatures for several decades. In contrast, the medium-scale (~782 m thick) Hoffell Granite Intrusion (HGI) functions as a sustained heat engine. The HGI formed via extreme fractional crystallization (>95%), where high magmatic halogen concentrations (F, Cl) depressed its solidus; this extended the cooling process and allowed the HGI to remain a viable heat source for over 7000 years. Analysis of quartz-hosted fluid inclusions within the HGI further tracks the chemical transition from metal-rich, salt-saturated magmatic brines to circulating meteoric fluids. Overall, these findings provide evidence of the geodynamic maturation of the GCV, documenting its transition from a rift-axis to a flank-zone environment. This integrated model provides essential tools for identifying deep heat sources and mitigating technical risks, such as halite scaling and chlorine-active corrosion, when drilling into the roots of high-temperature geothermal systems in active volcanic areas.

Flokkar í Opnum vísindum

Veldu flokk til að skoða.

Niðurstöður 1 - 9 af 9