| 461. |
- Sandberg, Martin, 1977, et al.
(författare)
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Fast tuning of superconducting microwave cavities
- 2008
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Ingår i: Proc. 2nd International Workshop on Solid-State Quantum Computing. - 9780735406056 ; , s. 12-21
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Konferensbidrag (refereegranskat)abstract
- Photons are fundamental excitations of electromagnetic fields and can be captured in cavities. For a given cavity with a certain size, the fundamental mode has a fixed frequency f which gives the photons a specific "color". The cavity also has a typical lifetime tau, which results in a finite linewidth delta f. If the size of the cavity is changed fast compared to tau, and so that the frequency change Delta f >> delta f, then it is possible to change the "color" of the captured photons. Here we demonstrate superconducting microwave cavities, with tunable effective lengths. The tuning is obtained by varying a Josephson inductance at one end of the cavity. We show data on four different samples and demonstrate tuning by several hundred linewidths in a time Delta t
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| 462. |
- Sandberg, Martin, 1977, et al.
(författare)
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Tuning the field in a microwave resonator faster than the photon lifetime
- 2008
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 92:20, s. 203501-
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Tidskriftsartikel (refereegranskat)abstract
- We have fabricated and characterized tunable superconducting transmission line resonators. To change the resonance frequency, we modify the boundary condition at one end of the resonator through the tunable Josephson inductance of a superconducting quantum interference device. We demonstrate a large tuning range (several hundred megahertz), high quality factors (10(4)), and that we can change the frequency of a few-photon field on a time scale orders of magnitude faster than the photon lifetime of the resonator. This demonstration has implications in a variety of applications.
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| 463. |
- Schwartz, Christofer, et al.
(författare)
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On-board Satellite Data Processing to Achieve Smart Information Collection
- 2022
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE-Intl Soc Optical Eng. - 9781510651524
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Konferensbidrag (refereegranskat)abstract
- Nowadays, it is a reality to launch, operate, and utilize small satellites at an affordable cost. However, bandwidth constraint is still an important challenge. For instance, multispectral and hyperspectral sensors generate a significant amount of data subjected to communication channel impairments, which is addressed mainly by source and channel coding aiming at an effective transmission. This paper targets a significant further bandwidth reduction by proposing an on-the-fly analysis technique on the satellite to decide which information is effectively useful for specific target applications, before coding and transmitting. The challenge would be detecting clouds and vessels having the measurements of red-band, green-band, blue-band, and near infrared band, aiming at sufficient probability of detection, avoiding false alarms. Furthermore, the embedded platform constraints must be satisfied. Experiments for typical scenarios of summer and winter days in Stockholm, Sweden, are conducted using data from the Mimir’s Well, the Saab AI-based data fusion system. Results show that non-relevant content can be identified and discarded, pointing out that for the cloudy scenarios evaluated, up to 73.1% percent of image content can be suppressed without compromising the useful information into the image. For the water regions in the scenarios containing vessels, results indicate that a stringent amount of data can be discarded (up to 98.5%) when transmitting only the regions of interest (ROI).
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| 464. |
- Schwartz, Christofer, et al.
(författare)
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Satellite Image Compression Guided by Regions of Interest
- 2023
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Ingår i: Sensors. - : MDPI. - 1424-8220. ; 23:2
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Tidskriftsartikel (refereegranskat)abstract
- Small satellites empower different applications for an affordable price. By dealing with a limited capacity for using instruments with high power consumption or high data-rate requirements, small satellite missions usually focus on specific monitoring and observation tasks. Considering that multispectral and hyperspectral sensors generate a significant amount of data subjected to communication channel impairments, bandwidth constraint is an important challenge in data transmission. That issue is addressed mainly by source and channel coding techniques aiming at an effective transmission. This paper targets a significant further bandwidth reduction by proposing an on-the-fly analysis on the satellite to decide which information is effectively useful before coding and transmitting. The images are tiled and classified using a set of detection algorithms after defining the least relevant content for general remote sensing applications. The methodology makes use of the red-band, green-band, blue-band, and near-infrared-band measurements to perform the classification of the content by managing a cloud detection algorithm, a change detection algorithm, and a vessel detection algorithm. Experiments for a set of typical scenarios of summer and winter days in Stockholm, Sweden, were conducted, and the results show that non-important content can be identified and discarded without compromising the predefined useful information for water and dry-land regions. For the evaluated images, only 22.3% of the information would need to be transmitted to the ground station to ensure the acquisition of all the important content, which illustrates the merits of the proposed method. Furthermore, the embedded platform’s constraints regarding processing time were analyzed by running the detection algorithms on Unibap’s iX10-100 space cloud platform.
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| 465. |
- Selegård, Linnéa, et al.
(författare)
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Bifunctional gadolinium decorated ZnO nanocrystals integrating both enhanced MR signal and bright fluorescence
- 2013
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Gadolinium decorated ZnO nanoparticles simultaneously possess both fluorescent and MR enhancement properties. These ZnO nanoparticles are crystalline and shielded by an amorphous gadolinium acetate matrix. Interestingly, the Gd-acetate decoration enhances the fluorescence emission of the ZnO nanoparticles. The quantum yield does increase for samples with high Gd/Zn relative ratios and these samples do also show a higher colloidal stability.In addition, these nanoparticles show an enhanced relaxivity value per Gd atom (r119.9mM1s-1) compared to results earlier reported both on Gd alloyed ZnO nanoparticles and pure Gd2O3 nanoparticles. This improvement is considered to be due to the close proximity of Gd atoms and surrounding water molecules. A comprehensive study of the quantum yield and the relaxivity, as a function of composition, enable us to identify the ultimate design/composition of gadolinium decorated ZnO nanoparticles for optimum fluorescence and MR enhancement properties.
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| 466. |
- Serneke, Byggkoncern
(författare)
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H22-huset : En ny bostadstyp mot ensamhet
- 2023
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Kan vi bygga bort ofrivillig ensamhet i Sverige? Inom det Vinnova-finansierade projektet H22 Alone Together har vi under två års tid ställt oss denna fråga. Resultatet av gemensamma krafter blev en helt ny bostadstyp, H22-huset.
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| 467. |
- Shayesteh, Alexander, et al.
(författare)
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Navigating in the fog : facing delays, rejection and ignorance when seeking help for primary hyperhidrosis
- 2021
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Ingår i: International Journal of Qualitative Studies on Health and Well-being. - : Taylor & Francis. - 1748-2623 .- 1748-2631. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Primary hyperhidrosis (PH) is a disease characterized by focal and excessive sweating.Purpose: The aim of this study was to describe the experiences of men and women with PH when seeking help for their condition.Method: A qualitative interview study with 30 men and women diagnosed with PH was conducted. Data was inductively analysed using manifest and latent content analysis.Results: The analysis resulted in a theme: Navigating in the fog, based on the categories doubtful encounters with health care professionals, helpful encounters with health care professionals, delays due to inadequate knowledge, and supported urge for help.Conclusions: Deficient knowledge and understanding about PH create a sense of resignation in individuals, resulting in delay of seeking treatment. Support from others, life-changing events, and finding information about PH were important motivating factors in seeking help and demanding access to treatment. A holistic approach towards patients with PH is important to reduce stigma and acknowledge the problems that are encountered in their daily lives. Educating health care professionals and students so that patients can be identified and assessed without delay and making information available about PH in schools and pharmacies could improve the general knowledge and facilitate obtaining treatment for individuals with PH.
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| 468. |
- Shirvany, Yazdan, 1980, et al.
(författare)
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Application of particle swarm optimization in epileptic spike EEG source localization
- 2013
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Ingår i: Applied Soft Computing Journal. - : Elsevier BV. - 1568-4946. ; 13:5, s. 2515-2525
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Tidskriftsartikel (refereegranskat)abstract
- Surgical therapy has become an important therapeutic alternative for patients with medically intractable epilepsy. Correct and anatomically precise localization of an epileptic focus is essential to decide if resection of brain tissue is possible. The inverse problem in EEG-based source localization is to determine the location of the brain sources that are responsible for the measured potentials at the scalp electrodes. We propose a new global optimization method based on particle swarm optimization (PSO) to solve the epileptic spike EEG source localization inverse problem. In a forward problem a modified subtraction method is proposed to reduce the computational time. The good accuracy and fast convergence are demonstrated for 2D and 3D cases with realistic head models. The results from the new method are promising for use in the pre-surgical clinic in the future
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| 469. |
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| 470. |
- Shirvany, Yazdan, 1980, et al.
(författare)
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Evaluation of a finite-element reciprocity method for epileptic EEG source localization: Accuracy, computational complexity and noise robustness
- 2013
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Ingår i: Biomedical Engineering Letters. - : Springer Science and Business Media LLC. - 2093-985X .- 2093-9868. ; 3:1, s. 8-16
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSEThe aim of this paper is to evaluate the performance of an EEG source localization method that combines a finite element method (FEM) and the reciprocity theorem.METHODSThe reciprocity method is applied to solve the forward problem in a four-layer spherical head model for a large number of test dipoles. To benchmark the proposed method, the results are compared with an analytical solution and two state-of-the-art methods from the literature. Moreover, the dipole localization error resulting from utilizing the method in the inverse procedure for a realistic head model is investigated with respect to EEG signal noise and electrode misplacement.RESULTSThe results show approximately 3% relative error between numerically calculated potentials done by the reciprocity theorem and the analytical solutions. When adding EEG noise with SNR between 5 and 10, the mean localization error is approximately 4.3 mm. For the case with 10 mm electrode misplacement the localization error is 4.8 mm. The reciprocity EEG source localization speeds up the solution of the inverse problem with more than three orders of magnitude compared to the state-of-the-art methods.CONCLUSIONSThe reciprocity method has high accuracy for modeling the dipole in EEG source localization, is robust with respect to noise, and faster than alternative methods.
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