| 1. |
- Toijer, Elin, et al.
(författare)
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Ab initio modelling of intergranular fracture of nickel containing phosphorus : Interfacial excess properties
- 2021
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Ingår i: Nuclear Materials and Energy. - : Elsevier BV. - 2352-1791. ; 28
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Tidskriftsartikel (refereegranskat)abstract
- In the present work, the impact of phosphorus impurities on the grain boundary strength of nickel has been investigated by means of density functional theory (DFT) modelling. Owing to different outcomes and trends previously reported in the literature, it is unclear whether P is strengthening or weakening the Ni grain boundary. To address this issue, we utilize three different DFT based methods: the excess-energy approach, rigid grain separation, and Rice-Wang's thermodynamic approach. The results show that the commonly used rigid model predicts P to have an increasing effect on the peak stress of Ni of up to 14%, as opposed to a reduction, which is indicated by the excess-energy approach. Employment of the Rice-Wang approach, on the other hand, displays a slight reduction in work of separation. The results show that the discrepancies between previous works can be attributed not so much to the physics of the system, but to the applied model, the partition scheme and the interpretation of the outcomes. This underlines the importance of a proper description of the fracture process, and shows that common simplifications can have a decisive impact on the observed trends.
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| 2. |
- Alawadi, Sadi, 1983-, et al.
(författare)
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A Federated Interactive Learning IoT-Based Health Monitoring Platform
- 2021
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Ingår i: New Trends in Database and Information Systems. - Cham : Springer. ; , s. 235-246, s. 235-246
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Konferensbidrag (refereegranskat)abstract
- Remote health monitoring is a trend for better health management which necessitates the need for secure monitoring and privacy-preservation of patient data. Moreover, accurate and continuous monitoring of personal health status may require expert validation in an active learning strategy. As a result, this paper proposes a Federated Interactive Learning IoT-based Health Monitoring Platform (FIL-IoT-HMP) which incorporates multi-expert feedback as ‘Human-in-the-loop’ in an active learning strategy in order to improve the clients’ Machine Learning (ML) models. The authors have proposed an architecture and conducted an experiment as a proof of concept. Federated learning approach has been preferred in this context given that it strengthens privacy by allowing the global model to be trained while sensitive data is retained at the local edge nodes. Also, each model’s accuracy is improved while privacy and security of data has been upheld.
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| 3. |
- Dominguez, Cecilia A., et al.
(författare)
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The DQB1*03:02 HLA haplotype is associated with increased risk of chronic pain after inguinal hernia surgery and lumbar disc herniation
- 2013
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Ingår i: Pain. - : Ovid Technologies (Wolters Kluwer Health). - 0304-3959 .- 1872-6623. ; 154:3, s. 427-433
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Tidskriftsartikel (refereegranskat)abstract
- Neuropathic pain conditions are common after nerve injuries and are suggested to be regulated in part by genetic factors. We have previously demonstrated a strong genetic influence of the rat major histocompatibility complex on development of neuropathic pain behavior after peripheral nerve injury. In order to study if the corresponding human leukocyte antigen complex (HLA) also influences susceptibility to pain, we performed an association study in patients that had undergone surgery for inguinal hernia (n = 189). One group had developed a chronic pain state following the surgical procedure, while the control group had undergone the same type of operation, without any persistent pain. HLA DRB1genotyping revealed a significantly increased proportion of patients in the pain group carrying DRB1*04 compared to patients in the pain-free group. Additional typing of the DQB1 gene further strengthened the association; carriers of the DQB1*03:02 allele together with DRB1*04 displayed an increased risk of postsurgery pain with an odds risk of 3.16 (1.61-6.22) compared to noncarriers. This finding was subsequently replicated in the clinical material of patients with lumbar disc herniation (n = 258), where carriers of the DQB1*03:02 allele displayed a slower recovery and increased pain. In conclusion, we here for the first time demonstrate that there is an HLA-dependent risk of developing pain after surgery or lumbar disc herniation; mediated by the DRB1*04 - DQB1*03:02 haplotype. Further experimental and clinical studies are needed to fine-map the HLA effect and to address underlying mechanisms.
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| 4. |
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| 5. |
- Engström, Jimmy
(författare)
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Scaling Indoor Positioning : improving accuracy and privacy of indoor positioning
- 2023
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Our phones have many uses for positioning technologies, such as navigation, LocationBased Services (LBS), emergency positioning, fitness applications, and advertising. We trust our phones and wearables to be location-aware. However, as soon as we enter a building, we can no longer use GPS signals, as their already weak signals are well below the background noise of the environment. This requires us to develop alternatives, such as installing active radio beacons, using existing radio infrastructure, applying environmental sensing based on barometric pressure and magnetic fields, or utilizing Inertial Measurement Units (IMUs) to estimate the user location. This licentiate thesis aims to evaluate beacon-based indoor positioning, where we assume installing a set of small battery-powered Bluetooth low-energy (BLE) beacons are possible. In particular, the thesis addresses essential factors such as installation effort, accuracy, the privacy aspects of an Indoor Positioning System(IPS), and mitigation of accuracy issues related to radio signal shadowing in complex indoor environments. The goal is to solve some obstacles to the widespread adoption of indoor positioning solutions.
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| 6. |
- Engström, Jimmy, et al.
(författare)
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Some Design Considerations in Passive Indoor Positioning Systems
- 2023
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Ingår i: Sensors. - : MDPI. - 1424-8220. ; 23:12
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Tidskriftsartikel (refereegranskat)abstract
- User location is becoming an increasingly common and important feature for a wide range of services. Smartphone owners increasingly use location-based services, as service providers add context-enhanced functionality such as car-driving routes, COVID-19 tracking, crowdedness indicators, and suggestions for nearby points of interest. However, positioning a user indoors is still problematic due to the fading of the radio signal caused by multipath and shadowing, where both have complex dependencies on the indoor environment. Location fingerprinting is a common positioning method where Radio Signal Strength (RSS) measurements are compared to a reference database of previously stored RSS values. Due to the size of the reference databases, these are often stored in the cloud. However, server-side positioning computations make preserving the user's privacy problematic. Given the assumption that a user does not want to communicate his/her location, we pose the question of whether a passive system with client-side computations can substitute fingerprinting-based systems, which commonly use active communication with a server. We compared two passive indoor location systems based on multilateration and sensor fusion using an Unscented Kalman Filter (UKF) with fingerprinting and show how these may provide accurate indoor positioning without compromising the user's privacy in a busy office environment.
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| 7. |
- Fazey, Ioan, et al.
(författare)
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Ten essentials for action-oriented and second order energy transitions, transformations and climate change research
- 2018
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Ingår i: Energy Research and Social Science. - : Elsevier BV. - 2214-6296 .- 2214-6326. ; 40, s. 54-70
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Forskningsöversikt (refereegranskat)abstract
- The most critical question for climate research is no longer about the problem, but about how to facilitate the transformative changes necessary to avoid catastrophic climate-induced change. Addressing this question, however, will require massive upscaling of research that can rapidly enhance learning about transformations. Ten essentials for guiding action-oriented transformation and energy research are therefore presented, framed in relation to second-order science. They include: (1) Focus on transformations to low-carbon, resilient living; (2) Focus on solution processes; (3) Focus on ‘how to’ practical knowledge; (4) Approach research as occurring from within the system being intervened; (5) Work with normative aspects; (6) Seek to transcend current thinking; (7) Take a multi-faceted approach to understand and shape change; (8) Acknowledge the value of alternative roles of researchers; (9) Encourage second-order experimentation; and (10) Be reflexive. Joint application of the essentials would create highly adaptive, reflexive, collaborative and impact-oriented research able to enhance capacity to respond to the climate challenge. At present, however, the practice of such approaches is limited and constrained by dominance of other approaches. For wider transformations to low carbon living and energy systems to occur, transformations will therefore also be needed in the way in which knowledge is produced and used.
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| 8. |
- Frostenson, Carl Mikael, 1992, et al.
(författare)
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Hard and soft materials: Putting consistent van der Waals density functionals to work
- 2022
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Ingår i: Electronic Structure. - : IOP Publishing. - 2516-1075. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- We present the idea and illustrate potential benefits of having a tool chain of closely related regular, unscreened and screened hybrid exchange-correlation (XC) functionals, all within the consistent formulation of the van derWaals density functional (vdW-DF) method (Hyldgaard et al (2020 J. Phys.: Condens. Matter 32 393001)). Use of this chain of nonempirical XC functionals allows us to map when the inclusion of truly nonlocal exchange and of truly nonlocal correlation is important. Here we begin the mapping by addressing hard and soft material challenges: Magnetic elements, perovskites, and biomolecular problems.We also predict the structure and polarization for a ferroelectric polymer. To facilitate this work and future broader explorations, we present a stress formulation for spin vdW-DF and illustrate the use of a simple stability-modeling scheme. The modeling supplements density functional theory (DFT) (with a specific XC functional) by asserting whether the finding of a soft mode (an imaginary-frequency vibrational mode, ubiquitous in perovskites and soft matter) implies an actual DFT-based prediction of a low-temperature transformation.
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| 9. |
- Gajdek, Dorotea, et al.
(författare)
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Structural Changes in Monolayer Cobalt Oxides under Ambient Pressure CO and O 2 Studied by In Situ Grazing-Incidence X-ray Absorption Fine Structure Spectroscopy
- 2022
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 126:7, s. 3411-3418
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Tidskriftsartikel (refereegranskat)abstract
- We have used grazing incidence X-ray absorption fine structure spectroscopy at the cobalt K-edge to characterize monolayer CoO films on Pt(111) under ambient pressure exposure to CO and O2, with the aim of identifying the Co phases present and their transformations under oxidizing and reducing conditions. X-ray absorption near edge structure (XANES) spectra show clear changes in the chemical state of Co, with the 2+ state predominant under CO exposure and the 3+ state predominant under O2-rich conditions. Extended X-ray absorption fine structure spectroscopy (EXAFS) analysis shows that the CoO bilayer characterized in ultrahigh vacuum is not formed under the conditions used in this study. Instead, the spectra acquired at low temperatures suggest formation of cobalt hydroxide and oxyhydroxide. At higher temperatures, the spectra indicate dewetting of the film and suggest formation of bulklike Co3O4 under oxidizing conditions. The experiments demonstrate the power of hard X-ray spectroscopy to probe the structures of well-defined oxide monolayers on metal single crystals under realistic catalytic conditions.
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