| 1. |
- Fang, Bo, et al.
(författare)
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Dual-Channel Neural Network for Atrial Fibrillation Detection From a Single Lead ECG Wave
- 2023
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Ingår i: IEEE journal of biomedical and health informatics. - : Institute of Electrical and Electronics Engineers (IEEE). - 2168-2194 .- 2168-2208. ; 27:5, s. 2296-2305
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Tidskriftsartikel (refereegranskat)abstract
- With the dramatic progress of wearable devices, continuous collection of single lead ECG wave is able to be implemented in a comfortable fashion. Data mining on single lead ECG wave is therefore attracting increasing attention, where atrial fibrillation (AF) detection is a hot topic. In this paper, we propose a dual-channel neural network for AF detection from a single lead ECG wave. Two primary phases are included, the data preprocessing part followed by a dual-channel neural network. A two-stage denoising procedure is developed for data preprocessing, so as to tackle the high noise and disturbance which generally resides in the ECG wave collected by wearable devices. Then the time-frequency spectrum and Poincare plot of the denoised ECG signal are imported into the developed dual-channel neural network for feature extraction and AF detection. On the 2017 PhysioNet/CinC Challenge database, the F1 values were 0.83, 0.90, and 0.75 for AF rhythm and normal rhythm, and other rhythm, respectively. The results well validate the effectiveness of the proposed method for AF detection from a single lead ECG wave, and also indicate its performance advantages over some state-of-the-art counterparts.
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| 2. |
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| 3. |
- Wang, JunXin, et al.
(författare)
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General Method for Determining Light Scattering and Absorption of Nanoparticle Composites
- 2019
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Ingår i: Advanced Optical Materials. - : Wiley-VCH Verlagsgesellschaft. - 2162-7568 .- 2195-1071. ; 7:4
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Tidskriftsartikel (refereegranskat)abstract
- Scattering and absorption from nanoparticles are of major importance in optical research as well as in a range of applications. The Kubelka–Munk two-flux radiative transfer model gives a simple description of light scattering in nanoparticle composite materials, but inversion of experimental transmittance and reflectance data to obtain backscattering and absorption coefficients remains challenging. Here, a general method for evaluating these parameters from transmittance and reflectance spectra, combined with spectral angle resolved light scattering measurements is developed. The angular dependence is approximatedby an extension of the empirical Reynolds–McCormick phase function, which is fitted to the experimental angle resolved light scattering data. This approach is verified by measurements on three typical nanoparticle/polymer composites containing plasmonic Au, ferromagnetic Fe3O4, and dielectric TiO2 particles. An approximation to the angular scattering pattern is further demonstrated, which can be applied to obtain the optical parameters using only reflectance and transmittance data, in cases where angle-resolved measurements are not available. These results can be extended to a wide range of isotropic, anisotropic, and multiple scattering systems, and will be highly useful in the fields of light scattering coatings/metamaterials, UV-shielding films, displays, absorption/scattering layers in solar cells and biological scatterers.
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| 4. |
- Barrios, David, et al.
(författare)
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Light Scattering Parameters of Polymer Dispersed Liquid Crystals Obtained by Inversion of Experimental Data
- 2022
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Ingår i: Proceedings of the Bremen Zoom Workshop on Light Scattering 2022. - : Leibniz Institute for Materials Engineering IWT. ; , s. 8-11
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Polymer Dispersed Liquid Crystal (PDLC) devices are electrically controlled smart windows, that switch from a translucent milky appearance (off state) to a transparent clear appearance (on state). We have studied the intrinsic and extrinsic scattering and absorption coefficients obtained by inversion of spectrophotometric transmittance and reflectance data. The inversion procedure uses two flux and four flux models and similar approximations for the average crossing parameter (ACP) as in our previous workon suspended particle devices [1]. Good fits are obtained, but the ACP approximation was found to be inconsistent with fitted parameters.
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| 5. |
- He, Tongyue, et al.
(författare)
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Toward Wearable Sensors : Advances, Trends, and Challenges
- 2023
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Ingår i: ACM Computing Surveys. - : Association for Computing Machinery (ACM). - 0360-0300 .- 1557-7341. ; 55:14S
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Forskningsöversikt (refereegranskat)abstract
- Sensors suitable for wearable devices have many special characteristics compared to other sensors, such as stability, sensitivity, sensor volume, biocompatibility, and so on. With the development of wearable technology, amazing wearable sensors have attracted a lot of attention, and some researchers have done a large number of technology explorations and reviews. However, previous surveys generally were concerned with a specified application and comprehensively reviewed the computing techniques for the signals required by this application, as well as how computing can promote data processing. There is a gap in the opposite direction, i.e., the fundamental data source actively stimulates application rather than from the application to the data, and computing promotes the acquisition of data rather than data processing. To fill this gap, starting with different parts of the body as the source of signal, the fundamental data sources that can be obtained and detected are explored by combining the three sensing principles, as well as discussing and analyzing the existing and potential applications of machine learning in simplifying sensor designs and the fabrication of sensors.
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| 6. |
- Jacobsson, Jesper, 1984-, et al.
(författare)
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An open-access database and analysis tool for perovskite solar cells based on the FAIR data principles
- 2022
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Ingår i: Nature Energy. - : Springer Nature. - 2058-7546. ; 7:1, s. 107-115
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Tidskriftsartikel (refereegranskat)abstract
- Large datasets are now ubiquitous as technology enables higher-throughput experiments, but rarely can a research field truly benefit from the research data generated due to inconsistent formatting, undocumented storage or improper dissemination. Here we extract all the meaningful device data from peer-reviewed papers on metal-halide perovskite solar cells published so far and make them available in a database. We collect data from over 42,400 photovoltaic devices with up to 100 parameters per device. We then develop open-source and accessible procedures to analyse the data, providing examples of insights that can be gleaned from the analysis of a large dataset. The database, graphics and analysis tools are made available to the community and will continue to evolve as an open-source initiative. This approach of extensively capturing the progress of an entire field, including sorting, interactive exploration and graphical representation of the data, will be applicable to many fields in materials science, engineering and biosciences.
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| 7. |
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| 8. |
- Niklasson, Gunnar A., 1953-, et al.
(författare)
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Inversion of Light Scattering Experiments by Using the Four-Flux Theory
- 2022
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Ingår i: Proceedings of the Bremen Zoom Workshop on Light Scattering 2022. - : Leibniz Institute for Materials Engineering IWT. ; , s. 40-43
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We discuss methods to use the four-flux theory to obtain parameters characterizing light scattering in particulate materials, by inversion of spectrophotometric transmittance and reflectance data. Specifically, we assess the possibility to simplify the inversion procedure by using approximations for some of the parameters of this theory, in particular the forward scattering ratios (FSR’s) and average pathlength parameters (APP’s), that are related to the angular distribution of the radiation field in the material. We also consider the possibility to obtain information on these parameters by angle resolved scattering measurements.
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| 9. |
- Niklasson, Gunnar A., 1953-, et al.
(författare)
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Optics of sunscreen lotions : Preliminary results on scattering and absorption coefficients
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Sunscreen lotions are used to protect the skin from damage due to solar ultraviolet (UV) radiation. The active UV-blocking components can be organic molecules or inorganic particles, for example TiO2. While both in-vivo and in-vitro methods exist for assessing the protective capacity of sunscreens, their basic optical properties have received little attention. In this paper we take the first steps to address this issue by presenting a method to obtain spectra of absorption and scattering coefficients of a sunscreen by analysis of experimental transmittance and reflectance spectra. We model the optical properties of the sunscreen by two-flux theory, develop approximate expressions for interface reflection coefficients and obtain the remaining optical parameters by fitting the two-flux theory to measurements. We analyze spectrophotometric reflectance and transmittance spectra of experimental narrow band UV blocking materials based on mesoporous magnesium carbonate – TiO2 mixtures, as well as some commercial sunscreens. Our method is demonstrated in vitro using quartz substrates and is further used to model in vivo measurements on the upside of the hand of one of the authors. The obtained absorption and scattering coefficient spectra give information on the relative contributions of these processes to the UV-blocking effect as well as the scattering of visible light responsible for the whitening of the skin upon application of a sunscreen lotion. Our analysis method may be useful for computational optimization of novel sunscreen formulations as well as for the development of in-vivo test methods.
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| 10. |
- Niklasson, Gunnar, 1953-, et al.
(författare)
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Light Scattering Parameters by Inversion of Experimental Data: The Case of Sunscreen Lotions
- 2021
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Ingår i: Proceedings of the Bremen Zoom Workshop on Light Scattering 2021. - Bremen : Leibniz Institute for Materials Engineering IWT. ; , s. 16-19
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Konferensbidrag (refereegranskat)abstract
- We present a method to obtain absorption and backscattering coefficients of a light scattering material and apply it to the technologically important case of sunscreen lotions. While both in-vivo and in-vitro methods exist for assessing the ultraviolet (UV) protective capacity of sun-screens, their basic optical properties have previously received little attention. We model the light scattering properties by two-flux theory and invert spectrophotometric total transmittance and reflectance measurements to obtain backscattering and absorption coefficient spectra.
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