Opin vísindi
Opin vísindi er varðveislusafn vísindaefnis og doktorsritgerða í opnum aðgangi á vegum íslenskra háskóla og Landsbókasafns Íslands - Háskólabókasafns.
Opinn aðgangur að rannsóknaniðurstöðum er í samræmi við 10. gr. laga nr. 3/2003 um opinberan stuðning við vísindarannsóknir sem og kröfur innlendra og erlendra rannsóknasjóða. Markmiðið með opnum aðgangi er að niðurstöður rannsókna séu aðgengilegar sem flestum óhindrað og án endurgjalds á rafrænu formi. Vistun í varðveislusafninu er varanleg og ætlað að tryggja aðgang að vísindaefni íslenskra háskóla í opnum aðgangi um ókomna tíð. Varðveislusafnið Opin vísindi er tengt við rannsóknagáttina IRIS og rannsóknaniðurstöður í opnum aðgangi sem eru skráðar í IRIS eru um leið vistaðar og gerðar aðgengilegar til framtíðar í varðveislusafninu. Með því að safna þessu efni saman í eitt safn verður aðgangur að því einfaldur og þægilegur fyrir alla sem vilja kynna sér það og geta þannig notið þess öfluga vísindastarfs sem fram fer í háskólum landsins.
Varðveislusafnið er OpenAIRE / OpenAIREplus samhæft og samrýmist kröfum sem gerðar eru um birtingu rannsóknaniðurstaðna úr verkefnum sem styrkt eru úr evrópsku rannsóknaáætlununum FP7 og H2020.
Varðveislusafnið notar opna hugbúnaðinn DSpace.
Opinn aðgangur að rannsóknaniðurstöðum er í samræmi við 10. gr. laga nr. 3/2003 um opinberan stuðning við vísindarannsóknir sem og kröfur innlendra og erlendra rannsóknasjóða. Markmiðið með opnum aðgangi er að niðurstöður rannsókna séu aðgengilegar sem flestum óhindrað og án endurgjalds á rafrænu formi. Vistun í varðveislusafninu er varanleg og ætlað að tryggja aðgang að vísindaefni íslenskra háskóla í opnum aðgangi um ókomna tíð. Varðveislusafnið Opin vísindi er tengt við rannsóknagáttina IRIS og rannsóknaniðurstöður í opnum aðgangi sem eru skráðar í IRIS eru um leið vistaðar og gerðar aðgengilegar til framtíðar í varðveislusafninu. Með því að safna þessu efni saman í eitt safn verður aðgangur að því einfaldur og þægilegur fyrir alla sem vilja kynna sér það og geta þannig notið þess öfluga vísindastarfs sem fram fer í háskólum landsins.
Varðveislusafnið er OpenAIRE / OpenAIREplus samhæft og samrýmist kröfum sem gerðar eru um birtingu rannsóknaniðurstaðna úr verkefnum sem styrkt eru úr evrópsku rannsóknaáætlununum FP7 og H2020.
Varðveislusafnið notar opna hugbúnaðinn DSpace.
Nýlega bætt við
Improving the demultiplexing performances of the multiple Bessel Gaussian beams (mBGBs)
(2021-11) Gong, Chaofan; Pan, Zhenzhen; Dedo, Maxime Irene; Sun, Jinghua; Wang, Lulu; Guo, Zhongyi; Department of Engineering
As approximate non-diffracted beams, Bessel Gaussian (BG) beams are more suitable to be used in free-space optical (FSO) communication system than Laguerre Gaussian (LG) vortex beams because of its self-recovering property. However, due to the limitation of its detection method, the multiplexing communication based on multiple Bessel Gaussian beams (mBGBs) has not been investigated deeply. In this paper, we propose a method for simultaneous demodulation of 36-mBGBs using 6 × 6 multiplexing phase hologram (MPH). To solve the problem that the energy of some BG beams are too low at the demodulation end, a method is proposed to optimize the pinhole size of the pinhole plate at the demodulation end. Compared with the traditional decomposition method, the proposed method not only improves the decoding efficiency greatly, but also has better robustness. In addition, the communication performance of 32-mBGBs encoded with four ASCII codes has been constructed and investigated numerically. The results show that the transmitted information can be clearly decoded by setting a reasonable threshold value, which is beneficial to the practical application of mBGBs in FSO communications.
Multifrequency microwave imaging for brain stroke detection
(2020) Wang, Lulu; Department of Engineering
CT and MRI are often used in the diagnosis and monitoring of stroke. However, they are expensive, time-consuming, produce ionizing radiation (CT), and not suitable for continuous monitoring stroke. Microwave imaging (MI) has been extensively investigated for identifying several types of human organs, including breast, brain, lung, liver, and gastric. The authors recently developed a holographic microwave imaging (HMI) algorithm for biological object detection. However, this method has difficulty in providing accurate information on embedded small inclusions. This paper describes the feasibility of the use of a multifrequency HMI algorithm for brain stroke detection. A numerical system, including HMI data collection model and a realistic head model, was developed to demonstrate the proposed method for imaging of brain tissues. Various experiments were carried out to evaluate the performance of the proposed method. Results of experiments carried out using multifrequency HMI have been compared with the results obtained from single frequency HMI. Results showed that multifrequency HMI could detect strokes and provide more accurate results of size and location than the single frequency HMI algorithm.
Occurrence graphs of patterns in permutations
(2019) Kristinsson, Bjarni Jens; Ulfarsson, Henning; Department of Computer Science
We define the occurrence graph Gp (π) of a pattern p in a permutation π as the graph whose vertices are the occurrences of p in π, with edges between the vertices if the occurrences differ by exactly one element. We then study properties of these graphs. The main theorem in this paper is that every hereditary property of graphs gives rise to a permutation class.
Multi-frequency holographic microwave imaging for breast lesion detection
(2019) Wang, Lulu; Department of Engineering
This paper presents the development of a multi-frequency holographic microwave imaging (HMI) algorithm and investigates the feasibility and effectiveness of the proposed algorithm for breast imaging. A realistic numerical system, including various realistic breast models and image data acquisition model, has been developed using the MATLAB software to demonstrate the working principle of the multi-frequency HMI method. Several numerical experiments have been conducted to evaluate the performance of the proposed method for breast tumor detection. A comparison study of single- and multi-frequency HMIs have been performed to investigate the effectiveness, sensitivity, and accuracy of the proposed method. Results demonstrated that the multi-frequency HMI could improve the breast image quality and accurately detect the small tumors even when they located inside dense tissue. Compared to the single-frequency HMI, the multi-frequency imaging approach could obtain detailed structural information about the breast and identify small lesions more accurately and effectively. The proposed method has the potential to become a great and helpful vision tool for investigating microwave diagnostic techniques.
Enhanced holographic microwave imaging for MNP target tumor detection
(2019) Wang, Lulu; Department of Engineering
Holographic microwave imaging (HMI) has been proposed as a potential imaging tool for breast cancer detection. However, this method is not sensitive enough to small tumors especially when they located inside the fibro-glandular tissue. This paper investigates the possibility of the use of enhanced HMI to improve the quality of breast image and diagnostic sensitivity by applying magnetic nanoparticles (MNP). A numerical system, including a realistic breast model, 16-element transducer array, a 2-element magnetic coil array, and an image processing model, has been developed to evaluate the effectiveness of the enhanced HMI method for mapping of a dense breast. The numerical results demonstrated that the proposed method could detect the MNP target breast tumor and distinguish the small tumor from fibro-glandular tissue in a dense breast, which has the potential to develop a useful imaging tool for early breast cancer detection in the future.
Flokkar í Opnum vísindum
Veldu flokk til að skoða.
- University of Iceland
- University of Akureyri
- Bifröst University
- Hólar University College
- IRIS
- Agricultural University of Iceland
- National and University Library of Iceland
- Iceland University of the Arts