| 1. |
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| 2. |
- Ahmadi, Omid, et al.
(författare)
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Revealing the deeper structure of the end-glacial Pärvie fault system in northern Sweden by seismic reflection profiling
- 2015
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Ingår i: Solid Earth Discussions. - : Copernicus GmbH. - 1869-9537 .- 1869-9529 .- 1869-9510. ; 6:2, s. 537-563
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Tidskriftsartikel (refereegranskat)abstract
- Fault scarps that extend up to 155 km and have offsets of tens of meters at the surface are present in the northern parts of Finland, Norway and Sweden. These fault scarps are inferred to have formed during earthquakes with magnitudes up to 8 at the time of the last deglaciation. The Pärvie fault system represents the largest earthquake so far documented in northern Scandinavia, both in terms of its length and its calculated magnitude. It is also the longest known glacially induced fault in the world. Present-day microearthquakes occur along the length of the fault scarp on the eastern side of the scarp, in general agreement with an east dipping main fault. In the central section of the fault, where there is a number of subsidiary faults east of the main fault, it has been unclear how the earthquakes relate to the faults mapped at the surface. A seismic profile across the Pärvie Fault system acquired in 2007, with a mechanical hammer as a source, showed a good correlation between the surface mapped faults and moderate to steeply dipping reflectors. The most pronounced reflector could be mapped to about 3 km depth. In an attempt to map the fault system to deeper levels, a new 22 km long 2-D seismic profile which followed the 2007 line was acquired in June 2014. For deeper penetration an explosive source with a maximum charge size of 8.34 kg in 20 m deep shot holes was used. Reflectors can now be traced to deeper levels with the main 65◦ east dipping fault interpreted as a weakly reflective structure. As in the previous profile, there is a pronounced strongly reflective 60◦ west dipping structure present to the east of the main fault that can now be mapped to about 8 km depth. Extrapolations of the main and subsidiary faults converge at a depth of about 11.5 km where current earthquake activity is concentrated, suggesting their intersection has created favorable conditions for seismic stress release. Based on the present and previous seismic reflection data, potential locations for future boreholes for drilling into the fault system are proposed.
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| 3. |
- Andersson, Magnus, et al.
(författare)
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Carbonatite ring-complexes explained by caldera-style volcanism
- 2013
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3
-
Tidskriftsartikel (refereegranskat)abstract
- Carbonatites are rare, carbonate-rich magmatic rocks that make up a minute portion of the crust only, yet they are of great relevance for our understanding of crustal and mantle processes. Although they occur in all continents and from Archaean to present, the deeper plumbing system of carbonatite ring-complexes is usually poorly constrained. Here, we show that carbonatite ring-complexes can be explained by caldera-style volcanism. Our geophysical investigation of the Alnö carbonatite ring-complex in central Sweden identifies a solidified saucer-shaped magma chamber at ∼3 km depth that links to surface exposures through a ring fault system. Caldera subsidence during final stages of activity caused carbonatite eruptions north of the main complex, providing the crucial element to connect plutonic and eruptive features of carbonatite magmatism. The way carbonatite magmas are stored, transported and erupt at the surface is thus comparable to known emplacement styles from silicic calderas.
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| 4. |
- Ask, Maria, et al.
(författare)
-
The Innovative Exploration Drilling and Data Acquisition Research School
- 2021
-
Ingår i: NSG2021 27th European Meeting of Environmental and Engineering Geophysics. - : European Association of Geoscientists and Engineers.
-
Konferensbidrag (refereegranskat)abstract
- The Innovative Exploration Drilling and Data Acquisition Research School (I-EDDA-RS) is aimed at educating emerging scientists and engineers in on-site drilling and geoscientific investigation technology for mining. I-EDDA-RS consists if a consortium of scientists and specialists from six universities and research institutes in Germany and Sweden. A central component of the research school is that the courses have hands-on components at drill sites, boreholes and repositories. In addition, a course on entrepreneurial skills required in the exploration industry is also included in I-EDDA-RS. The arrival of the Covid-19 pandemic resulted in altered plans. Instead of offering ten courses with strong field work, practical, and entrepreneurial components during 2020, four courses via distant learning were offered. While this was disappointing in many aspects, two of the courses attracted a larger group of students from a wider part of the world than original envisioned. Outreach via on-line and open webinars is also a route to explore, as a complement to meetings and conferences in real life. The I-EDDA-RS courses in 2021 welcomes students at MSc & PhD level, as well as experienced professionals for lifelong learning (c.f. https://www.iedda.eu/rs). The form and type of teaching is to be determined.
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| 5. |
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| 6. |
- Cheng, Jie, et al.
(författare)
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Optimal Carrier Frequency Design for Frequency Diverse Array Mimo Radar
- 2023
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Ingår i: ICASSP 2023 - 2023 IEEE International Conference on Acoustics, Speech and Signal Processing, Proceedings. - 1520-6149. - 9781728163277 ; 2023-June
-
Konferensbidrag (refereegranskat)abstract
- In this work, we introduce a novel approach for designing the transmit frequency offset scheme based on Cramér-Rao lower bound (CRLB) minimization for a frequency diverse array multiple-input multiple-output (FDA-MIMO) radar. The problem originates in non-uniform FDA radar where each frequency offset scheme derives from a specific mathematical model, but where no optimization is conducted with respect to the frequency offset design. We propose two frequency selection schemes for FDA-MIMO radar based on A-optimal minimization, both incorporating a priori knowlegdge. The worst case optimal FDA-MIMO (OFDA-MIMOW) radar forms the frequency selection by minimizing the CRLB over a grid of the unknown parameters, whereas the Bayesian optimal FDA-MIMO (OFDA-MIMO-B) radar instead minimizes the Bayesian CRLB (BCRLB). The performances of the methods are evaluated using simulated data and compared to other common frequency selection schemes.
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| 7. |
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| 8. |
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European Geosciences Union General Assembly 2016 : EGU Division Energy, Resources & the Environment (ERE)
- 2016
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Proceedings (redaktörskap) (refereegranskat)abstract
- The EGU General Assembly 2016 was held under the conference theme “Active Planet” from 16-22 April 2016 in Vienna, Austria. The program consisted of 619 unique scientific sessions and 321 side events. A total of 16,300 contributions were presented in the form of posters (64%), oral presentations (30%) and interactive content (PICO, 6%). The 13,650 participants originate from 109 countries, of which the majority were early career scientists (53%) and students (25%). Over the last decade, EGU has expanded in terms of number of scientific contributions (62% increase) and number of participants (57% increase).The scientific program of the Division Energy, Resources & the Environment (ERE) was organized around six main groups of sessions: (1) integrated studies, (2) impact of energy and resource exploitation on the environment, (3) non-carbon based energy, (4) carbon based energy, (5) geo-storage for a sustainable future, and (6) geo-materials from natural resources. The division hosted 19 sessions and co-organized further 13 with others. In total, 458 presentations came from ERE, corresponding to almost 3% of all contributions of the EGU General Assembly 2016.This special issue presents some of the current and coming applied research topics within the fields of energy, resources and the environment, and also documents the ERE activities at the recent EGU General Assembly. Below, a brief description of the scientific program [1] is given, sorted with respect to the six main groups of sessions. Comparable overview issues were published in Energy Procedia in previous years [2-4].
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| 9. |
- García Juanatey, María de los Angeles, et al.
(författare)
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2D and 3D MT in the central Skellefte Ore District, northern Sweden
- 2019
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Ingår i: Tectonophysics. - : Elsevier BV. - 0040-1951 .- 1879-3266. ; 764, s. 124-138
-
Tidskriftsartikel (refereegranskat)abstract
- New broadband magnetotelluric (MT) data have been acquired along two parallel profiles in the central part of the metallogenic Skellefte district in northern Sweden. The data were recorded as part of the Swedish 4D modelling of mineral belts project and cover an area with several economical and sub-economical deposits. The dimensionality and quality of the data were carefully analyzed and new error floors were systematically determined prior to inverse modelling in 2D and 3D. The algorithms used were EMILIA and WSINV3DMT. For the 2D inversion, only the determinant of the impedance tensor was used, while for the 3D inversion all elements were considered. The obtained models fit the inverted data, and image the main regional features. A detailed comparison reveals the superiority of the 3D model, both in model structures and data fit. After assessing the main features in the model, an interpretation is proposed and refined with the support of previous geophysical studies. The most interesting features are large and medium-sized conductors associated with crustal-scale shear zones and faults within the Skellefte Group rocks. These may be depicting a network of fossil pathways for hydrothermal fluid transport and as such, provide new insight into past processes in the area.
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| 10. |
- Garcia Juanatey, Maria de los Angeles, et al.
(författare)
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Integrated MagnetoTelluric and seismic reflection study : Skellefte Ore District, northern Sweden
- 2011
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Konferensbidrag (refereegranskat)abstract
- The Skellefte District is a very rich mining area in northern Sweden. The main deposits consist of volcanic-hosted massive sulphides VHMS rich in zinc, copper, lead, gold and silver. Since the area has been mined and explored for over a century, today's challenge is to locate deeper deposits. The VINNOVA 4D modeling project aims to address this challenge by understanding the regional setting of the district and its evolution over time. © 2011 Society of Exploration Geophysicists.
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| 11. |
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| 12. |
- García Juanatey, María de los Ángeles, et al.
(författare)
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MT and reflection seismics in northwestern Skellefte Ore District, Sweden
- 2013
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Ingår i: Geophysics. - : Society of Exploration Geophysicists. - 0016-8033 .- 1942-2156. ; 78:2, s. B65-B76
-
Tidskriftsartikel (refereegranskat)abstract
- A seismic reflection and MT survey was carried out along a 27-km long transect in northwestern Skellefte District, as part of a bigger 3D modeling project. The main motivation for the data acquisition is to elucidate the geologic relationship between the known mineralizations in the Adak mining camp to the north and in the well studied Kristineberg area south of the transect. The seismic reflection data were acquired with a VIBSIST system, and show reflectivity down to 3 s. Apart from the conventional processing for crystalline environments, the seismic data was also subject to an azimuthal binning procedure and cross-dip analysis, allowing the orientation of planar reflectors in 3D. Regarding the MT data, it is primarily of good quality along the 17 installed sites. The inversion of the determinant of the impedance tensor yielded a stable 2D resistivity model, dominated by resistors corresponding to the postorogenic intrusions along the transect. Adding the location of the analyzed seismic reflectors in the MT inversion rendered an integrated model that facilitated a preliminary joint interpretation of the data sets. Overall, the results are in good agreement with surface observations and reveal a crude configuration of the geologic units below the transect. The most prominent outcomes are the lateral and depth extent of the large postorogenic intrusions in the area reaching to 5- or 6-km depth, the dimensions of the nearly vertical Brännäs gabbro extending to 6-km depth, and the presence of enhanced conductivities along the transect at about 10 km depth. The latter is probably related to the deep conductor previously identified in the district.
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| 13. |
- Hellman, Per, et al.
(författare)
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Surgical strategy for large or malignant endocrine pancreatic tumors
- 2000
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Ingår i: World Journal of Surgery. - : Springer Science and Business Media LLC. - 0364-2313 .- 1432-2323. ; 24:11, s. 1353-1360
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Tidskriftsartikel (refereegranskat)abstract
- Endocrine pancreatic tumors (EPTs) are rare but have a remarkably better prognosis than adenocarcinoma of the pancreas. Patients with EPTs benefit from surgical and medical therapy, which may alleviate symptoms due to hormonal excess and increase survival. Patients with large or malignant EPTs with infiltrative disease may suffer from local complications, including gastrointestinal bleeding and obstruction and involvement of the superior mesenteric (SMV) and portal (PV) veins. Among 31 patients with operable and large or malignant EPTs, 7 had hormone-producing syndromes (insulin, glucagon), and 24 had clinically nonfunctioning EPTs. Surgery in these patients included vascular reconstruction of the SMV/PV (n = 4), resection of infiltrated adjacent organs (n = 5; stomach, transverse colon), or resection of concomitant liver metastases (n = 3). Four patients with conspicuously large insulinomas, and three with glucagonoma were successfully operated on with alleviation of hormonal symptoms. Among the 24 nonfunctioning EPTs, 5 patients had been explored earlier and their tumors judged inoperable due to locally invasive disease or misdiagnosis as pancreatic adenocarcinoma. The operations were performed with no mortality and low morbidity. We conclude that large and malignant EPTs with limited spread of disease may benefit from a combination of medical and surgical therapy.
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| 14. |
- Håkansson, Maria, 1977-
(författare)
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Playing with Context : Explicit and Implicit Interaction in Mobile Media Applications
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis contributes with insights into how aspects of the surrounding physical and social context can be exploited in the design of mobile media applications for playful use. In this work, context refers to aspects of the immediate surroundings – outside of the device – that can be identified and measured by sensors; for instance environmental aspects like sound, and social aspects like co-located people. Two extensive case studies explore the interplay between users, mobile media, and aspects of context in different ways, and how it can invite playful use. The first case study, Context Photography, uses sensor-based information about the immediate physical surroundings to affect images in real time in a novel digital camera application for everyday creativity. The second, Push!Music, makes it possible to share music both manually and autonomously between co-located people, based on so-called media context, for spontaneous music sharing.The insights gained from the designs, prototypes, and user studies, point at the value of combining explicit and implicit interaction – essentially, the expected and unexpected – to open for playful use. The explicit interaction encouraged users to be active, exploratory, and creative. The implicit interaction let users embrace and exploit dynamic qualities of the surroundings, contributing to making the systems fun, exciting, magical, ‘live’, and real. This combination was facilitated through our approach to context, where sensor-based information was mostly open in use and interpretation, ambiguous, visible, and possible to override for users, and through giving the systems a degree of agency and autonomy. A key insight is that the combination of explicit and implicit interaction allowed both control and a sense of magic in the interaction with the mobile media applications, which together seems to encourage play and playfulness.
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| 15. |
- Juhlin, Christopher, et al.
(författare)
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Energy, Resources & the Environment : Current Status
- 2014
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 59, s. 440-444
-
Tidskriftsartikel (refereegranskat)abstract
- The EGU gathers geoscientists from Europe and the rest of the world, covering all disciplines of geosciences. Geoscientific interdisciplinarity is needed to tackle future challenges. A major challenge regards the provision of adequate and reliable supplies of affordable energy and resources obtained in environmentally sustainable ways, which are essential for economic prosperity, environmental quality and political stability around the world. One goal of the ERE division is to be a leading discussion forum for these subjects. The contributions in this issue present some of the challenges that were presented in the ERE division at the EGU General Assembly in 2014.
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| 16. |
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| 17. |
- Juhlin, Eva
(författare)
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Traces of Mathematical Facts and Students’ Understanding of the Concept `Quadrilateral´ : An enquiry into young students’ communication
- 2015
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mathematics could be described as a special kind of language, a discourse in which participants communicate abstract concepts. Communication and language are known to be important factors in teaching and learning but little is known about neither communication between students in relation to geometrical concepts, nor what traces of mathematical facts and understanding is incorporated into their communication. Such knowledge would contribute to teachers´ understanding of students’ knowledge of this aspect of mathematical thinking. The purpose of this study is to investigate young students’ communication in the Discourse of geometry. To accomplish this, Swedish students aged between ten and eleven were video-recorded while working with two assignments, one involving describing quadrilaterals to each other and the other sorting quadrilaterals. An analysis of the students’ communication has identified a number of issues that teachers could benefit from being aware of in their teaching of the concept of `geometrical figure´. Examples of issues identified being that conceptual characteristic remain too much in the background of what in the study has been called the visual shape. For example, a long and narrow shape of a geometrical figure seems to draw students’ attention. Students also seem to be having difficulty in understanding that naming a figure is a way of merging the figures´ definitions into one word, and there were problems with words that anchor in daily life.
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| 18. |
- Juhlin, Kristina, et al.
(författare)
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Using VigiBase to Identify Substandard Medicines : Detection Capacity and Key Prerequisites
- 2015
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Ingår i: Drug Safety. - : Springer Science and Business Media LLC. - 0114-5916 .- 1179-1942. ; 38:4, s. 373-382
-
Tidskriftsartikel (refereegranskat)abstract
- Background Substandard medicines, whether the result of intentional manipulation or lack of compliance with good manufacturing practice (GMP) or good distribution practice (GDP), pose a significant potential threat to patient safety. Spontaneous adverse drug reaction reporting systems can contribute to identification of quality problems that cause unwanted and/or harmful effects, and to identification of clusters of lack of efficacy. In 2011, the Uppsala Monitoring Centre (UMC) constructed a novel algorithm to identify reporting patterns suggestive of substandard medicines in spontaneous reporting, and applied it to VigiBase (R), the World Health Organization's global individual case safety report database. The algorithm identified some historical clusters related to substandard products, which were later able to be confirmed in the literature or by contact with national centres (NCs). As relevant and detailed information is often lacking in the VigiBase reports but might be available at the reporting NC, further evaluation of the algorithm was undertaken with involvement from NCs. Objective To evaluate the effectiveness of an algorithm that identifies clusters of potentially substandard medicines, when these are assessed directly at the NC concerned. Methods The algorithm identifies countries and time periods with disproportionately high reporting of product inadequacy. NCs with at least 20 clusters were eligible to participate in the study, and six NCs-those in the Republic of Korea, Malaysia, Singapore, South Africa, the UK and the USA-were selected, taking into account the geographical spread and prevalence of recent clusters. The clusters were systematically assessed at the NCs, following a standardized protocol, and then compiled centrally at the UMC. The clusters were classified as 'confirmed', 'potential' or 'unlikely' substandard products; or as 'confirmed not substandard' when confirmed by an investigation; or as 'indecisive' when the information available did not allow a sound assessment even at the NC. Results The assessment of a total of 147 clusters resulted in 8 confirmed, 12 potential and 51 unlikely substandard products, and a further 19 clusters were confirmed as not substandard. Reflecting the difficulty of evaluating suspected substandard products retrospectively when additional information from the primary reporter, as well as samples, are no longer available, 57 clusters were classified as indecisive. Conclusion While application of the algorithm to VigiBase allowed identification of some substandard medicines, some key prerequisites have been identified that need to be fulfilled at the national level for the algorithm to be useful in practice. Such key factors are fast handling and transfer of incoming reports into VigiBase, detailed information on the product and its distribution channels, the possibility of contacting primary reporters for further information, availability of samples of suspected products and laboratory capacity to analyse suspected products.
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| 19. |
- Juhlin, Maria, et al.
(författare)
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Defining Graph Signal Distances Using an Optimal Mass Transport Framework
- 2019
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Ingår i: 2019 27th European Signal Processing Conference, EUSIPCO 2019. - 9789082797039 - 9781538673003 ; 2019
-
Konferensbidrag (refereegranskat)abstract
- In this work, we propose a novel measure of distance for quantifying dissimilarities between signals observed on a graph. Building on a recently introduced optimal mass transport framework, the distance measure is formed using the second-order statistics of the graph signals, allowing for comparison of graph processes without direct access to the signals themselves, while explicitly taking the dynamics of the underlying graph into account. The behavior of the proposed distance notion is illustrated in a graph signal classification scenario, indicating attractive modeling properties as compared to the standard Euclidean metric.
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| 20. |
- Juhlin, Maria, et al.
(författare)
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Estimating faults modes in ball bearing machinery using a sparse reconstruction framework
- 2018
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Ingår i: 2018 26th European Signal Processing Conference, EUSIPCO 2018. - 9789082797015 ; 2018-September, s. 2330-2334
-
Konferensbidrag (refereegranskat)abstract
- In this work, we present a computationally efficient algorithm for estimating fault modes in ball bearing systems. The presented method generalizes and improves upon earlier developed sparse reconstruction techniques, allowing for detecting multiple fault modes. The measured signal is corrupted with additive and multiplicative noise, yielding a signal that is highly erratic. Fortunately, the damaged ball bearings give rise to strong periodical structures which may be exploited when forming the proposed detector. Numerical simulations illustrate the preferred performance of the proposed method.
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| 21. |
- Juhlin, Maria
(författare)
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Exploiting Sparse Structures in Source Localization and Tracking
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the modeling of structured signals under different sparsity constraints. Many phenomena exhibit an inherent structure that may be exploited when setting up models, examples include audio waves, radar, sonar, and image objects. These structures allow us to model, identify, and classify the processes, enabling parameter estimation for, e.g., identification, localisation, and tracking.In this work, such structures are exploited, with the goal to achieve efficient localisation and tracking of a structured source signal. Specifically, two scenarios are considered. In papers A and B, the aim is to find a sparse subset of a structured signal such that the signal parameters and source locations maybe estimated in an optimal way. For the sparse subset selection, a combinatorial optimization problem is approximately solved by means of convex relaxation, with the results of allowing for different types of a priori information to be incorporated in the optimization. In paper C, a sparse subset of data is provided, and a generative model is used to find the location of an unknown number of jammers in a wireless network, with the jammers’ movement in the network being tracked as additional observations become available.
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| 22. |
- Juhlin, Maria, et al.
(författare)
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Fast Gridless Estimation of Damped Modes
- 2018
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Ingår i: 2018 International Symposium on Intelligent Signal Processing and Communication Systems.
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Konferensbidrag (refereegranskat)
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| 23. |
- Juhlin, Maria, et al.
(författare)
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Identifying Decaying Sinusoidal Modes Using Signed Measurements
- 2019
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Ingår i: 2019 IEEE 8th International Workshop on Computational Advances in Multi-Sensor Adaptive Processing, CAMSAP 2019 - Proceedings. - 9781728155494 ; , s. 76-80
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we generalize the one-bit quantized low resolution RELAX algorithm to allow for exponentially decaying modes. The resulting greedy algorithm exploits a time-varying threshold to allow for the estimation of the parameters detailing the modes. The improvement offered by the proposed algorithm as compared to its predecessor, and the corresponding Cramér-Rao Lower Bound, is illustrated using numerical examples.
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| 24. |
- Juhlin, Maria, et al.
(författare)
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Localization Of Multiple Jammers In Wireless Sensor Networks
- 2021
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Ingår i: 29th European Signal Processing Conference, EUSIPCO 2021 - Proceedings. - 2219-5491. - 9789082797060 ; 2021-August, s. 1596-1600
-
Konferensbidrag (refereegranskat)abstract
- Wireless sensor networks are susceptible to jamming attacks that can result in communication breakdowns. Preemptive measures to prevent jamming attacks is an active research field, but to stop an ongoing attack often requires that one is able to locate jammers in order to neutralize them. Several methods exist for the case when the network is corrupted by a single jammer, although these generally do not allow for cases when more than one jammer is present. In this work, we introduce an iterative procedure that determines the number of jammers corrupting the network as part of the localization of the jammers. The performance of the method is illustrated using numerical examples.
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| 25. |
- Juhlin, Maria, et al.
(författare)
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Optimal microphone placement for localizing tonal sound sources
- 2021
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Ingår i: 28th European Signal Processing Conference, EUSIPCO 2020 - Proceedings. - 2219-5491. - 9789082797053 ; 2021-January, s. 236-240
-
Konferensbidrag (refereegranskat)abstract
- This work is concerned with determining optimal microphone placements that allow for an accurate location estimate of the sound sources, taking into account the expected signal structure of voiced speech, as well as the expected location areas and the typical range of the fundamental frequencies of the speakers. To determine preferable microphone placements, we propose a scheme that minimizes a theoretical lower bound on the variance of the location estimates over the possible sensor placements, while taking into account the expected variability in the impinging signals. Numerical examples and real measurements illustrate the performance of the proposed scheme.
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| 26. |
- Juhlin, Maria, et al.
(författare)
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Optimal sensor placement for localizing structured signal sources
- 2023
-
Ingår i: Signal Processing. - : Elsevier BV. - 0165-1684. ; 202
-
Forskningsöversikt (refereegranskat)abstract
- This work is concerned with determining optimal sensor placements that allow for an accurate location estimate of structured signal sources, taking into account the expected location areas and the typical range of the parameters detailing the signals. In the presentation, we illustrate the technique for tonal sound signals, exploiting the expected harmonic structure of such signals. To determine preferable sensor placements, we propose a computationally efficient scheme that minimizes theoretical lower bounds on the variance of the location estimate over the possible sensor placements, while taking into account the expected variability in the impinging signals, and introducing various forms of constraints on the optimization. Numerical examples and real measurements illustrate the performance of the proposed scheme.
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| 27. |
- Juhlin, Maria, et al.
(författare)
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Sparse Chroma Estimation for Harmonic Non-Stationary Audio
- 2015
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Ingår i: Signal Processing Conference (EUSIPCO), 2015 23rd European. ; , s. 26-30
-
Konferensbidrag (refereegranskat)abstract
- In this work, we extend on our recently proposed block sparse chroma estimator, such that the method also allows for signals with time-varying envelopes. Using a spline-based amplitude modulation of the chroma dictionary, the refined estimator is able to model longer frames than our earlier approach, as well as to model highly time-localized signals, and signals containing sudden bursts, such as trumpet or trombone signals, thus retaining more signal information than other methods for chroma estimation. The performance of the proposed estimator is evaluated on a recorded trumpet signal, clearly illustrating the improved performance, as compared to other used techniques.
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| 28. |
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| 29. |
- Kronvall, Ted, et al.
(författare)
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Sparse Chroma Estimation for Harmonic Audio
- 2015
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Ingår i: 2015 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). - 2379-190X. - 9781467369978 ; , s. 579-583
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Konferensbidrag (refereegranskat)abstract
- This work treats the estimation of the chromagram for harmonic audio signals using a block sparse reconstruction framework. Chroma has been used for decades as a key tool in audio analysis, and is typically formed using a Fourier-based framework that maps the fundamental frequency of a musical tone to its corresponding chroma. Such an approach often leads to problems with tone ambiguity, which we avoid by taking into account the harmonic structure and perceptional attributes in music. The performance of the proposed method is evaluated using real audio files, clearly showing preferable performance as compared to other commonly used methods.
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| 30. |
- Kronvall, Ted, et al.
(författare)
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Sparse Modeling of Chroma Features
- 2017
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Ingår i: Signal Processing. - : Elsevier BV. - 0165-1684. ; 130, s. 105-117
-
Tidskriftsartikel (refereegranskat)abstract
- This work treats the estimation of chroma features for harmonic audio signals using a sparse reconstruction framework. Chroma has been used for decades as a key tool in audio analysis, and is typically formed using a periodogram-based approach that maps the fundamental frequency of a musical tone to its corresponding chroma. Such an approach often leads to problems with tone ambiguity. We address this ambiguity via sparse modeling, allowing us to appropriately penalize ambiguous estimates while taking the harmonic structure of tonal audio into account. Furthermore, we also allow for signals to have time-varying envelopes. Using a spline-based amplitude modulation of the chroma dictionary, the presented estimator is able to model longer frames than what is conventional for audio, as well as to model highly time-localized signals, and signals containing sudden bursts, such as trumpet or trombone signals. Thus, we may retain more signal information as compared to alternative methods. The performances of the proposed methods are evaluated by analyzing the average estimation errors for synthetic signals, as compared to the Cramér–Rao lower bound, and by visual inspection for estimates of real instrument signals. The results show strong visual clarity, as compared to other commonly used methods.
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| 31. |
- Kuehn, Michael, et al.
(författare)
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Sustainable Supply of Resources and Energy is a Challenge
- 2015
-
Ingår i: European Geosciences Union General Assembly 2015 - Division Energy, Resources And Environment, EGU 2015. - : Elsevier BV. ; 76, s. 1-6
-
Konferensbidrag (refereegranskat)abstract
- The European Geosciences Union brings together geoscientists from all over Europe and the rest of the world, covering all disciplines of the earth sciences. This geoscientific inter- and multi-disciplinarity is needed to tackle the challenges of the future. A major challenge for humankind is to provide adequate and reliable supplies of affordable energy and other resources. These should be obtained in environmentally sustainable ways, which is essential for economic prosperity, environmental quality and political stability around the world. This issue gives a general overview of contributions during the General Assembly 2015 in the division for Energy, Resources & the Environment.
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| 32. |
- Kühn, Michael, et al.
(författare)
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Interdisciplinary Approaches in Resource and Energy Research to Tackle the Challenges of the Future
- 2016
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Ingår i: European Geosciences Union General Assembly 2016. - : Elsevier BV. ; 97, s. 1-6
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Konferensbidrag (refereegranskat)abstract
- The Division Energy, Resources & the Environment (ERE) of the European Geosciences Union (EGU) provides an international platform for scientists from a wide range of fields with the common denominator that their research topics have high societal relevance. The ERE community develops approaches for the solution of global economic prosperity, environmental quality and political stability based on interdisciplinary research on adequate and reliable supplies of affordable energy and other resources in environmentally sustainable ways. This special issue presents contributions of the ERE division at the EGU General Assembly in 2016.
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| 33. |
- Mochalina, Natalia, et al.
(författare)
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Antithrombotic therapy in patientswith non-valvular atrial fibrillation in Southern Sweden : A population-based cohort study
- 2016
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Ingår i: Thrombosis Research. - : Elsevier BV. - 0049-3848 .- 1879-2472. ; 140, s. 94-99
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Oral anticoagulants in patients with atrial fibrillation (AF) with moderate-to-high stroke risk are strongly recommended by the current guidelines.Materials and methods: Population-based register study of all 13,837 patients with incident non-valvular AF diagnosed during 2011-2014 in primary and secondary care (including all in-and outpatient visits) in Skane County, Sweden. The outcome was the prescription of direct-acting oral anticoagulants (DOAC), warfarin or acetylsalicylic acid (ASA).Results and conclusion: Guideline adherence increased from 47.6% in 2011 to 66.1% in 2014, mostly due to decrease in undertreatment. In patients with CHA(2)DS(2)-VASc score >= 2, ASA uptake decreased from 29.9% to 14.7% and DOAC uptake increased from 2.1% to 25.1%. The use of ASA was more common among elderly and with increasing stroke-and bleeding risk. Overall, 47.4% of patients with CHA(2)DS(2)-VASc score >= 2 did not receive oral anticoagulants. Undertreatment was particularly common in women < 65 years (55.8%) and in patients >84 years (65.3% in women and 62% in men). Overtreatment of patients at low stroke risk was 35.9% in men and 36.4% in women. Provider speciality affected the choice of treatment only to a minor degree. Despite increasing guideline adherence, there is a suboptimal use of antithrombotic therapy in a large proportion of AF patients diagnosed in different clinical settings. Efforts to further improve guideline adherence should particularly be targeted on women < 65 years, elderly > 84 years and patients at low stroke risk.
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| 34. |
- Muhamad, Harbe Anwar, et al.
(författare)
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Analysis of borehole geophysical data from the Mora area of the Siljan Ring impact structure, central Sweden
- 2015
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Ingår i: Journal of Applied Geophysics. - : Elsevier BV. - 0926-9851 .- 1879-1859. ; 115, s. 183-196
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Tidskriftsartikel (refereegranskat)abstract
- The Siljan impact structure is the largest known impact structure in Europe, the result of a Late Devonian meteorite impact (380.9 +/- 4.6 Ma). It is outlined mainly by a ring of lakes and Palaeozoic sedimentary rocks of Ordovician to Devonian age. The Palaeozoic successions are generally poorly exposed, but often well preserved with clear stratigraphy. At some locations they are strongly tectonised with sharply inclined or nearly overturned packages of crystalline basement and/or sediments. Down-hole logging data were acquired in the western part of the Siljan impact structure to determine some of the physical properties of the Palaeozoic sedimentary rocks in the area. Boreholes Mora 001 (356 m logged depth), Vattumyra Production (420 m logged depth), Mora VM 2 (94 m logged depth) and Mobillyft (437 m logged depth) were logged for temperature, sonic velocity and electrical resistivity. Logging data were compared to the lithology in the Mora 001 core, which had been mapped in detail, and information from other cores in the area. Good agreement between the natural gamma log and the core lithology was found. The sonic log shows a marked difference in velocity for the more clastic Silurian succession compared to the Ordovician succession and the Precambrian basement. A synthetic seismogram shows that a high amplitude reflection is expected at the Silurian-Ordovician boundary, raising some questions concerning interpretation of a seismic profile located about 6-7 km north of the study area. Correlation of the borehole logs shows that the thickness of the Silurian succession varies rapidly in the area and that its composition differs over distances of less than 1 km. These rapid variations suggest that the study area may be located in a megablock zone that was highly influenced by the impact Caledonian tectonics and changing depositional environments may also play a role in explaining the present-day borehole lithologies. Even though the boreholes are relatively far from the seismic profile and the geology is complex, the new data confirm that the Silurian has significant thickness along parts of the seismic profile. Potentially, the Silurian can be up to 450 m thick on parts of the profile. Further geophysical investigations in the area, including seismic surveying and gravity measurements, may help in mapping the complex structures away from the boreholes and discriminating between possible geological models.
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| 35. |
- Ohlsson, Marcus Andreas, et al.
(författare)
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Midlife risk factor exposure and incidence of cardiac arrest depending on cardiac or non-cardiac origin
- 2017
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Ingår i: International Journal of Cardiology. - : Elsevier BV. - 0167-5273. ; 240, s. 398-402
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Little is known about midlife risk factors of future cardiac arrest. Our objective was to evaluate cardiovascular risk factors in midlife in relation to the risk of cardiac arrest (CA) of cardiac and non-cardiac origin later in life. Methods: We cross-matched individuals of the population based Malmö Diet and Cancer study (n = 30,447) with the local CA registry of the city of Malmö. Baseline exposures were related to incident CA. Results: During a mean follow-up of 17.6. ±. 4.6. years, 378 CA occurred, of whom 17.2% survived to discharge. Independent midlife risk factors for CA of cardiac origin included coronary artery disease (HR 2.84 (1.86-4.34) (p <. 0.001)), diabetes mellitus (HR 2.37 (1.61-3.51) (p <. 0.001)) and smoking (HR 1.95 (1.49-2.55) (p <. 0.001)). Dyslipidemia and history of stroke were also significantly associated with an elevated risk for CA of cardiac origin.Independent midlife risk factors for CA of non-cardiac origin included obesity (BMI>30kg/m2) (HR 2.37 (1.51-3.71) (p <0.001)), smoking (HR 2.05 (1.33-3.15) (p <0.001)) and being on antihypertensive treatment (HR 2.25 (1.46-3.46) (p <0.001)). Conclusion: Apart from smoking, which increases the risk of CA in general, the midlife risk factor pattern differs between CA of cardiac and non-cardiac origin. Whereas CA of cardiac origin is predicted by history of cardiovascular disease, dyslipidemia and diabetes mellitus, the main risk factors for CA of non-cardiac origin are obesity and hypertension. In addition to control of classical cardiovascular risk factors for prevention of CA, our results suggest that prevention of midlife obesity may reduce the risk of CA of non-cardiac origin.
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| 36. |
- Ohlsson, Marcus Andreas, et al.
(författare)
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Risk prediction of future cardiac arrest by evaluation of a genetic risk score alone and in combination with traditional risk factors
- 2020
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Ingår i: Resuscitation. - : Elsevier BV. - 0300-9572. ; 146, s. 74-79
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Coronary heart disease (CHD) is a leading cause of death globally, commonly through sudden cardiac death. Cardiac arrest of cardiac origin (CA) is associated with a poor prognosis and there is a great need for risk assessment and intensified preventive actions. In this study we aim to assess if a genetic risk score for CHD, composed of 50 common CHD susceptibility variants (GRS), predicts CA and to evaluate a novel composite risk score including traditional risk factors as well as GRS. Methods: The GRS score alone and in combination with traditional CHD risk factors were examined in relation to CA incidence among 23 000 middle aged subjects during 18.9 years of follow-up. The cohort excluded patients with a diagnosed history of CHD, heart failure or stroke. Results: Two-hundred-fifty-two patients suffered a cardiac arrest during the follow up, of which 181 were CA. In a multivariate model with CHD risk factors, high versus low genetic risk predicted CA with a hazard ratio (HR) of 2.49 {(95% CI 1.50–4.12) (P < 0.001)}, surpassed only by higher estimates for male sex {HR = 2.91 (95% CI 2.09–4.06) (P < 0.001)}, ages 50–65 {HR = 2.74 (95% CI 1.42–5.25) (P = 0.003)} and ages 65–74 {HR = 5.10 (95% CI 2.56–10.16) (P < 0.001)}. Smoking, dyslipidemia, hypertension and diabetes mellitus also predicted CA but with lower HRs than GRS. A novel composite risk score including CHD risk factors as well as GRS predicted CA with a HR = 110.81 {(95% CI 15.43–795.63) (P < 0.001)} for the highest (5) versus the lowest quintile (1) of the risk score. Conclusions: Genetic risk of CHD is strongly associated with incident CA and when combined with traditional CHD risk factors may identify individuals who benefit from intensified preventive pharmacological treatment.
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| 37. |
- Ohlsson, Marcus Andreas, et al.
(författare)
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Validation of the good outcome following attempted resuscitation score on in-hospital cardiac arrest in southern Sweden
- 2016
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Ingår i: International Journal of Cardiology. - : Elsevier BV. - 0167-5273. ; 221, s. 294-297
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Tidskriftsartikel (refereegranskat)abstract
- Background There is a great need for a simple and clinically useful instrument to help physicians estimate the probability of survival to discharge with a good neurological outcome (cerebral performance category, CPC = 1) in cases of in-hospital cardiac arrest (IHCA). Our aim was to validate the “Good Outcome Following Attempted Resuscitation” (GO-FAR) score in a different country with different demographics than previously investigated. Methods A retrospective observational study including all cases of IHCA who were part of a cardiac arrest registry at Skåne University Hospital in Sweden 2007–2010. Results Two-hundred-eighty-seven patients suffered IHCA during the period. A majority were male and mean age was 70 years. Overall survival to discharge independent of neurological function was 20.2%; 78% of the survivors had CPC = 1 and survival to discharge with CPC = 1 was 15.7%. The area under the receiver operating characteristics curve for the GO-FAR score was 0.85 (CI = 0.78–0.91, p
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| 38. |
- Skyttä, Pietari, et al.
(författare)
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Crustal 3-D geometry of the Kristineberg area (Sweden) with implications on VMS deposits
- 2013
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Ingår i: Solid Earth. - : Copernicus GmbH. - 1869-9510 .- 1869-9529. ; 4, s. 387-404
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Tidskriftsartikel (refereegranskat)abstract
- Structural analysis of the Palaeoproterozoic volcanogenic massive sulfide (VMS) hosting Kristineberg area, Sweden, constrained by existing magnetotelluric (MT) and seismic reflection data, reveals that the complex geometry characterized by non-cylindrical antiformal structures is due to transpression along the termination of a major high-strain zone. Similar orientations of the host rock deformation fabrics and the VMS ore lenses indicate that the present-day geometry of the complex VMS deposits in the Kristineberg area may be attributed to tectonic transposition. The tectonic transposition was dominantly controlled by reverse shearing and related upright to overturned folding, with increasing contribution of strike-slip shearing and sub-horizontal flow towards greater crustal depths. Furthermore, the northerly dip of the previously recognized subsurface crustal reflector within the Kristineberg area is attributed to formation of crustal compartments with opposite polarities within the scale of the whole Skellefte district. The resulting structural framework of the main geological units is visualized in a 3-D model which is available as a 3-D PDF document through the publication website.
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| 39. |
- Trobos, Margarita, 1980, et al.
(författare)
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In vitro evaluation of barrier function against oral bacteria of dense and expanded polytetrafluoroethylene (PTFE) membranes for guided bone regeneration
- 2018
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Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1523-0899. ; 20:5, s. 738-748
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Tidskriftsartikel (refereegranskat)abstract
- Aim: This study evaluates biofilm formation and barrier function against Streptococcus oralis of nonresorbable polytetrafluoroethylene (PTFE) guided bone regeneration membranes having expanded (e-PTFE) and dense (d-PTFE) microstructure. Materials and Methods: Three e-PTFE membranes of varying openness, one d-PTFE membrane, and commercially pure titanium discs were evaluated. All e-PTFE membranes consisted of PTFE nodes interconnected by fibrils. The d-PTFE membrane was fibril-free, with large evenly spaced indentations. The surfaces were challenged with S. oralis and incubated statically for 2-48 h. Bacterial colonization, viability, and penetration were evaluated. Results: S. oralis numbers increased over time on all surfaces, as observed using scanning electron microscopy, while cell viability decreased, as measured by colony forming unit (CFU) counting. At 24 h and 48 h, biofilms on d-PTFE were more mature and thicker (tower formations) than on e-PTFE, where fewer layers of cells were distributed mainly horizontally. Biofilms accumulated preferentially within d-PTFE membrane indentations. At 48 h, greater biofilm biomass and number of viable S. oralis were found on d-PTFE compared to e-PTFE membranes. All membranes were impermeable to S. oralis cells. Conclusions: All PTFE membranes were effective barriers against bacterial passage in vitro. However, d-PTFE favored S. oralis biofilm formation.
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| 40. |
- Winzell Juhlin, Åsa, et al.
(författare)
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Hearing acuity in nonagenarians aged 90 and 95 assessed in a home setting using standardized pure-tone audiometry
- 2024
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Ingår i: INTERNATIONAL JOURNAL OF AUDIOLOGY. - 1499-2027 .- 1708-8186.
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Knowledge regarding hearing acuity in the nonagenarian age group is sparse. In this study we aimed to advance our understanding of hearing loss in the 10th decade of life. Design: A cross-sectional study in which standardised hearing measurements were performed during home visits, which included care home facilities and nursing homes to maximise participation. Study sample: Two unselected groups of individuals aged 90 (n = 42) and 95 (n = 49), sampled from the population-based Gothenburg H70 Birth Cohort Studies. Results: 98% of the participants (95% CI [95, 100]) had some degree of hearing loss in their better ear, with 83% (95% CI [73, 89]) having a potentially disabling hearing loss of moderate degree or worse, according to WHO criteria. Furthermore, differences between the two age groups (five years apart) indicate an increasing hearing loss, primarily at frequencies >= 2 kHz. Conclusion: Hearing loss was present in almost all of the participants in the nonagenarian age group and among a majority of them potentially to a degree that would warrant rehabilitation. Carrying out standardised hearing measurements in a home setting was feasible in this age group and enhanced the representativeness of the study population.
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| 41. |
- Xu, Zhuo, et al.
(författare)
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Extrapolated supervirtual refraction interferometry
- 2021
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Ingår i: Geophysical Journal International. - : Oxford University Press. - 0956-540X .- 1365-246X. ; 227:2, s. 1439-1463
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Tidskriftsartikel (refereegranskat)abstract
- Accurate picking of head-wave arrival times is an important component of first-arrival traveltime tomography. Far-offset traces in particular have low signal-to-noise ratio (SNR), but picking on these traces is necessary in order to obtain velocity information at depth. Furthermore, there is often an insufficient number of far-offset traces for obtaining reliable models at depth. We present here an extrapolation method for increasing the number of first arrivals beyond the maximum recorded offset, thereby extending the supervirtual refraction interferometry (SVI) method. We refer to the method as extrapolated SVI (ESVI). It is a novel attempt to extrapolate first arrivals using a fully data-driven method. We first test the methodology on synthetic data sets, and we then apply ESVI to two published real data sets over the Parvie fault system in northern Sweden. These data sets were acquired along the same profile at different times with different acquisition parameters and noise levels. The results show that ESVI enhances the SNR of head waves when the noise level is high. That is the same as the conventional SVI. ESVI also increases the number of pickable first arrivals by extrapolating head waves past the original maximum offset of each shot. We also show that the significant increase in first-arrival traveltime picks is beneficial for improving resolution and penetration depth in the tomographic imaging and, consequently, better revealing the subsurface velocity distribution. The tomographic images show higher velocities in the hanging walls of the main Parvie fault and another subsidiary fault, as interpreted relative to migrated images from previous seismic reflection processing.
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| 42. |
- Yan, Ping, et al.
(författare)
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A magnetotelluric investigation of the Scandinavian Caledonides in western Jämtland, Sweden, using the COSC borehole logs as prior information
- 2017
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Ingår i: Geophysical Journal International. - : Oxford University Press (OUP). - 0956-540X .- 1365-246X. ; 208:3, s. 1465-1489
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Tidskriftsartikel (refereegranskat)abstract
- In connection with the Collisional Orogeny in the Scandinavian Caledonides (COSC) project, broad-band magnetotelluric (MT) data were acquired at 78 stations along a recent ca. 55km- long NW-SE directed reflection seismic profile (referred to as the COSC Seismic Profile; CSP), with the eastern end located similar to 30 km to the west of the orogenic Caledonian front. The MT component of the project aims at (i) delineating the highly conductive (similar to 0.1 Omega . m) alum shales that are associated with an underlying main decollement and (ii) calibrating the MT model to borehole logs. Strike and distortion analyses of the MT data show a 3-D structure in the western 10 km of the profile around the 2.5 km deep COSC-1 borehole (IGSN: ICDP5054EHW1001) and a preferred strike angle of N34 degrees E in the central and eastern parts of the profile. 2-D modelling of MT impedances was tested using different inversion schemes and parameters. To adjust the resistivity structure locally around the borehole, resistivity logging data from COSC-1 were successfully employed as prior constraints in the 2-D MT inversions. Compared with the CSP, the model inverted from the determinant impedances shows the highest level of structural similarity. A shallow resistor (> 1000 Omega . m) in the top 2-3 km depth underneath the western most 10 km of the profile around COSC-1 corresponds to a zone of high seismic reflectivity, and a boundary at less than 1 km depth where the resistivity decreases rapidly from > 100 to < 1 Omega . m in the central and eastern parts of the profile coincides with the first seismic reflections. The depth to this boundary is well constrained as shown by 1-D inversions of the MT data from five selected sites and it decreases towards the Caledonian front in the east. Underneath the easternmost part of the profile, the MT data show evidence of a second deeper conductor (resistivity < 1 Omega . m) at > 3 km depth. Based upon the COSC-1 borehole logs, the CSP reflection seismic image, and the surface geologic map, the MT resistivity models were interpreted geologically. In the vicinity of COSC-1, the resistor down to 2-3 km depth pertains to the metamorphic Middle Allochthon. The up to 1000-m-thick shallow resistor in the central and eastern parts of the profile is interpreted to overly an imbricated unit at the bottom of the Lower Allochthon that includes the alum shales. In the MT resistivity model, the 300-500 m thick imbricated unit masks the main Caledonian decollement at its bottom. A second possible interpretation, though not favoured here, is that the decollement occurs along a much deeper seismic reflection shallowing from 4.5 km depth in the west to similar to 600 m depth in the east. An additional borehole (COSC-2) is planned to penetrate the Lower Allochthon and the main decollement surface in the central part of the profile and can provide information to overcome this interpretational ambiguity. Using a synthetic study, we evaluate how resistivity logs from COSC-2 can improve the 2-D inversion model.
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