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  1. Article ; Online: Collaborative and individual learning of geography in immersive virtual reality: An effectiveness study.

    Sedlák, Michal / Šašinka, Čeněk / Stachoň, Zdeněk / Chmelík, Jiří / Doležal, Milan

    PloS one

    2022  Volume 17, Issue 10, Page(s) e0276267

    Abstract: Many university-taught courses moved to online form since the outbreak of the global pandemic of coronavirus disease (COVID-19). Distance learning has become broadly used as a result of the widely applied lockdowns, however, many students lack personal ... ...

    Abstract Many university-taught courses moved to online form since the outbreak of the global pandemic of coronavirus disease (COVID-19). Distance learning has become broadly used as a result of the widely applied lockdowns, however, many students lack personal contact in the learning process. A classical web-based distance learning does not provide means for natural interpersonal interaction. The technology of immersive virtual reality (iVR) may mitigate this problem. Current research has been aimed mainly at specific instances of collaborative immersive virtual environment (CIVE) applications for learning. The fields utilizing iVR for knowledge construction and skills training with the use of spatial visualizations show promising results. The objective of this study was to assess the effectiveness of collaborative and individual use of iVR for learning geography, specifically training in hypsography. Furthermore, the study's goals were to determine whether collaborative learning would be more effective and to investigate the key elements in which collaborative and individual learning were expected to differ-motivation and use of cognitive resources. The CIVE application developed at Masaryk University was utilized to train 80 participants in inferring conclusions from cartographic visualizations. The collaborative and individual experimental group underwent a research procedure consisting of a pretest, training in iVR, posttest, and questionnaires. A statistical comparison between the geography pretest and posttest for the individual learning showed a significant increase in the score (p = 0.024, ES = 0.128) and speed (p = 0.027, ES = 0.123), while for the collaborative learning, there was a significant increase in the score (p<0.001, ES = 0.333) but not in speed (p = 1.000, ES = 0.000). Thus, iVR as a medium proved to be an effective tool for learning geography. However, comparing the collaborative and individual learning showed no significant difference in the learning gain (p = 0.303, ES = 0.115), speed gain (p = 0.098, ES = 0.185), or performance motivation (p = 0.368, ES = 0.101). Nevertheless, the collaborative learning group had significantly higher use of cognitive resources (p = 0.046, ES = 0.223) than the individual learning group. The results were discussed in relation to the cognitive load theories, and future research directions for iVR learning were proposed.
    MeSH term(s) Humans ; COVID-19/epidemiology ; COVID-19/prevention & control ; Communicable Disease Control ; Virtual Reality ; Learning ; Geography
    Language English
    Publishing date 2022-10-18
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2267670-3
    ISSN 1932-6203 ; 1932-6203
    ISSN (online) 1932-6203
    ISSN 1932-6203
    DOI 10.1371/journal.pone.0276267
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Assessment of retinal vein pulsation through video-ophthalmoscopy and simultaneous biosignals acquisition.

    Kolar, Radim / Vicar, Tomas / Chmelik, Jiri / Jakubicek, Roman / Odstrcilik, Jan / Valterova, Eva / Nohel, Michal / Skorkovska, Karolina / Tornow, Ralf P

    Biomedical optics express

    2023  Volume 14, Issue 6, Page(s) 2645–2657

    Abstract: The phenomenon of retinal vein pulsation is still not a deeply understood topic in retinal hemodynamics. In this paper, we present a novel hardware solution for recording retinal video sequences and physiological signals using synchronized acquisition, ... ...

    Abstract The phenomenon of retinal vein pulsation is still not a deeply understood topic in retinal hemodynamics. In this paper, we present a novel hardware solution for recording retinal video sequences and physiological signals using synchronized acquisition, we apply the photoplethysmographic principle for the semi-automatic processing of retinal video sequences and we analyse the timing of the vein collapse within the cardiac cycle using of an electrocardiographic signal (ECG). We measured the left eyes of healthy subjects and determined the phases of vein collapse within the cardiac cycle using a principle of photoplethysmography and a semi-automatic image processing approach. We found that the time to vein collapse (T
    Language English
    Publishing date 2023-05-12
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2572216-5
    ISSN 2156-7085
    ISSN 2156-7085
    DOI 10.1364/BOE.486052
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Deep-learning-based fully automatic spine centerline detection in CT data.

    Jakubicek, Roman / Chmelik, Jiri / Ourednicek, Petr / Jan, Jiri

    Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference

    2019  Volume 2019, Page(s) 2407–2410

    Abstract: In this contribution, we present a fully automatic approach, that is based on two convolution neural networks (CNN) together with a spine tracing algorithm utilizing a population optimization algorithm. Based on the evaluation of 130 CT scans including ... ...

    Abstract In this contribution, we present a fully automatic approach, that is based on two convolution neural networks (CNN) together with a spine tracing algorithm utilizing a population optimization algorithm. Based on the evaluation of 130 CT scans including heavily distorted and complicated cases, it turned out that this new combination enables fast and robust detection with almost 90% of correctly determined spinal centerlines with computing time of fewer than 20 seconds.
    MeSH term(s) Algorithms ; Deep Learning ; Humans ; Neural Networks, Computer ; Spine/diagnostic imaging ; Tomography, X-Ray Computed
    Language English
    Publishing date 2019-12-30
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 2694-0604
    ISSN (online) 2694-0604
    DOI 10.1109/EMBC.2019.8856528
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Digital restoration of fragmentary human skeletal remains: Testing the feasibility of virtual reality.

    Jurda, Mikoláš / Urbanová, Petra / Chmelík, Jiří

    Journal of forensic and legal medicine

    2019  Volume 66, Page(s) 50–57

    Abstract: Experts in forensic anthropology and medicine have become gradually accustomed to examining components of the human body in the virtual workspace. While the computer-assisted approach offers numerous benefits, the interactions with digital three- ... ...

    Abstract Experts in forensic anthropology and medicine have become gradually accustomed to examining components of the human body in the virtual workspace. While the computer-assisted approach offers numerous benefits, the interactions with digital three-dimensional biological objects are often problematic, particularly if conducted with mouse, keyboard and flat-panel screen. The study focusses on feasibility of a virtual reality (VR) system for virtual restoration of fragmentary skeletal remains. The VR system was confronted with three cases of fragmentary remains. The cases were reassembled manually by twenty participants using a HTC Vive headset combined with an in-house application A.R.T. The same task was performed using a CloudCompare software in conjunction with a desktop peripheral. The two systems were compared in terms of time efficiency, the geometric properties of the resulting restorations, and convenience of use. Restoration using the VR system took approximately half the time the desktop set-up did. The VR system also yielded a lower error rate when a severely fragmented skull was reassembled. Ultimately, although the efficiency of the reassembling was shown to be strongly dependent on the operator's experience, the use of the VR system balanced out the uneven levels of proficiency in computer graphics. The current generation of virtual reality headsets has a strong potential to facilitate and improve tasks relating to the virtual restoration of fragmented skeletal remains. A VR system offers an intuitive digital working environment which is less affected by an operator's computer skills and practical understanding of the technology than the desktop systems are.
    MeSH term(s) Adult ; Body Remains ; Feasibility Studies ; Female ; Forensic Anthropology/methods ; Humans ; Image Processing, Computer-Assisted ; Imaging, Three-Dimensional ; Male ; Skull Fractures/diagnostic imaging ; Software ; Virtual Reality ; Wounds, Gunshot/diagnostic imaging
    Language English
    Publishing date 2019-06-14
    Publishing country England
    Document type Comparative Study ; Journal Article
    ZDB-ID 2268721-X
    ISSN 1878-7487 ; 1752-928X
    ISSN (online) 1878-7487
    ISSN 1752-928X
    DOI 10.1016/j.jflm.2019.06.005
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Book ; Online: An Immersive Virtual Environment for Collaborative Geovisualization

    Dolezal, Milan / Chmelik, Jiri / Liarokapis, Fotis

    2020  

    Abstract: This paper presents an immersive virtual reality environment that can be used to develop collaborative educational applications. Multiple users can collaborate within the virtual shared space and communicate with each other through voice. To asses the ... ...

    Abstract This paper presents an immersive virtual reality environment that can be used to develop collaborative educational applications. Multiple users can collaborate within the virtual shared space and communicate with each other through voice. To asses the feasibility of the collaborative environment a novel case-study concerned the education of a geography was developed and evaluated. The geovisualization experiment scenario explores the possibility of learning geography in a collaborative virtual environment. A user-study with 30 participants was performed. Participants evaluated and commented on the usability and interaction methods used within the virtual environment.

    Comment: 4 pages, 7 figures
    Keywords Computer Science - Human-Computer Interaction
    Publishing date 2020-10-13
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Book ; Online: A Tool for Automatic Estimation of Patient Position in Spinal CT Data

    Jakubicek, Roman / Vicar, Tomas / Chmelik, Jiri

    2020  

    Abstract: Much of the recently available research and challenge data lack the meta-data containing any information about the patient position. This paper presents a tool for automatic rotation of CT data into a standardized (HFS) patient position. The proposed ... ...

    Abstract Much of the recently available research and challenge data lack the meta-data containing any information about the patient position. This paper presents a tool for automatic rotation of CT data into a standardized (HFS) patient position. The proposed method is based on the prediction of rotation angle with CNN, and it achieved nearly perfect results with an accuracy of 99.55 %. We provide implementations with easy to use an example for both Matlab and Python (PyTorch), which can be used, for example, for automatic rotation correction of VerSe2020 challenge data.

    Comment: 6 pages, 3 figures, submitted on EMBEC 2020; the paper has not been reviewed yet
    Keywords Physics - Medical Physics ; Computer Science - Computer Vision and Pattern Recognition ; Electrical Engineering and Systems Science - Image and Video Processing
    Publishing date 2020-06-27
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Book ; Online: Localization and classification of intracranialhemorrhages in CT data

    Nemcek, Jakub / Jakubicek, Roman / Chmelik, Jiri

    2020  

    Abstract: Intracranial hemorrhages (ICHs) are life-threatening brain injures with a relatively high incidence. In this paper, the automatic algorithm for the detection and classification of ICHs, including localization, is present. The set of binary convolutional ... ...

    Abstract Intracranial hemorrhages (ICHs) are life-threatening brain injures with a relatively high incidence. In this paper, the automatic algorithm for the detection and classification of ICHs, including localization, is present. The set of binary convolutional neural network-based classifiers with a designed cascade-parallel architecture is used. This automatic system may lead to a distinct decrease in the diagnostic process's duration in acute cases. An average Jaccard coefficient of 53.7 % is achieved on the data from the publicly available head CT dataset CQ500.

    Comment: Submitted on EMBEC 2020, paper has not been reviewed yet, 7 pages
    Keywords Physics - Medical Physics ; Computer Science - Computer Vision and Pattern Recognition ; Electrical Engineering and Systems Science - Image and Video Processing
    Publishing date 2020-09-07
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article: A Comparison of Monoscopic and Stereoscopic 3D Visualizations: Effect on Spatial Planning in Digital Twins

    Herman, Lukáš / Juřík, Vojtěch / Snopková, Dajana / Chmelík, Jiří / Ugwitz, Pavel / Stachoň, Zdeněk / Šašinka, Čeněk / Řezník, Tomáš

    Remote Sensing. 2021 July 28, v. 13, no. 15

    2021  

    Abstract: From the user perspective, 3D geospatial data visualizations are one of the bridges between the physical and the digital world. As such, the potential of 3D geospatial data visualizations is frequently discussed within and beyond the digital twins. The ... ...

    Abstract From the user perspective, 3D geospatial data visualizations are one of the bridges between the physical and the digital world. As such, the potential of 3D geospatial data visualizations is frequently discussed within and beyond the digital twins. The effects on human cognitive processes in complex spatial tasks is rather poorly known. No uniform standards exist for the 3D technologies used in these tasks. Although stereoscopic geovisualizations presented using 3D technologies enhance depth perception, it has been suggested that the visual discomfort experienced when using 3D technology outweighs its benefits and results in lower efficiency and errors. In the present study, sixty participants using 3D technologies were tested in terms of their ability to make informed decisions in selecting the correct position of a virtual transmitter in a digital twin and a digital terrain model, respectively. Participants (n = 60) were randomly assigned into two groups, one using 3D technology engaging stereoscopic shutter glasses and the second working with standard computer screen-based visualizations. The results indicated that the participants who used shutter glasses performed significantly worse in terms of response time (W = 175.0; p < 0.001, r = −0.524). This finding verifies previous conclusions concerning the unsuitability of stereoscopic visualization technology for complex decision-making in geospatial tasks.
    Keywords cognition ; computers ; decision making ; humans ; landscapes ; models ; spatial data
    Language English
    Dates of publication 2021-0728
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article
    ZDB-ID 2513863-7
    ISSN 2072-4292
    ISSN 2072-4292
    DOI 10.3390/rs13152976
    Database NAL-Catalogue (AGRICOLA)

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  9. Article ; Online: Cancer cell viscoelasticity measurement by quantitative phase and flow stress induction.

    Vicar, Tomas / Chmelik, Jiri / Navratil, Jiri / Kolar, Radim / Chmelikova, Larisa / Cmiel, Vratislav / Jagos, Jiri / Provaznik, Ivo / Masarik, Michal / Gumulec, Jaromir

    Biophysical journal

    2022  Volume 121, Issue 9, Page(s) 1632–1642

    Abstract: Cell viscoelastic properties are affected by the cell cycle, differentiation, and pathological processes such as malignant transformation. Therefore, evaluation of the mechanical properties of the cells proved to be an approach to obtaining information ... ...

    Abstract Cell viscoelastic properties are affected by the cell cycle, differentiation, and pathological processes such as malignant transformation. Therefore, evaluation of the mechanical properties of the cells proved to be an approach to obtaining information on the functional state of the cells. Most of the currently used methods for cell mechanophenotyping are limited by low robustness or the need for highly expert operation. In this paper, the system and method for viscoelasticity measurement using shear stress induction by fluid flow is described and tested. Quantitative phase imaging (QPI) is used for image acquisition because this technique enables one to quantify optical path length delays introduced by the sample, thus providing a label-free objective measure of morphology and dynamics. Viscosity and elasticity determination were refined using a new approach based on the linear system model and parametric deconvolution. The proposed method allows high-throughput measurements during live-cell experiments and even through a time lapse, whereby we demonstrated the possibility of simultaneous extraction of shear modulus, viscosity, cell morphology, and QPI-derived cell parameters such as circularity or cell mass. Additionally, the proposed method provides a simple approach to measure cell refractive index with the same setup, which is required for reliable cell height measurement with QPI, an essential parameter for viscoelasticity calculation. Reliability of the proposed viscoelasticity measurement system was tested in several experiments including cell types of different Young/shear modulus and treatment with cytochalasin D or docetaxel, and an agreement with atomic force microscopy was observed. The applicability of the proposed approach was also confirmed by a time-lapse experiment with cytochalasin D washout, whereby an increase of stiffness corresponded to actin repolymerization in time.
    MeSH term(s) Cytochalasin D ; Elastic Modulus ; Elasticity ; Neoplasms ; Reproducibility of Results ; Viscosity
    Chemical Substances Cytochalasin D (22144-77-0)
    Language English
    Publishing date 2022-04-04
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 218078-9
    ISSN 1542-0086 ; 0006-3495
    ISSN (online) 1542-0086
    ISSN 0006-3495
    DOI 10.1016/j.bpj.2022.04.002
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: Geography Education in a Collaborative Virtual Environment: A Qualitative Study on Geography Teachers

    Jochecová, Kateřina / Černý, Michal / Stachoň, Zdeněk / Švedová, Hana / Káčová, Natálie / Chmelík, Jiří / Brůža, Vojtěch / Kvarda, Ondřej / Ugwitz, Pavel / Šašinková, Alžběta / Fořtová, Nicola Catherine / Šašinka, Čeněk

    ISPRS international journal of geo-information. 2022 Mar. 08, v. 11, no. 3

    2022  

    Abstract: The presented study aspires to utilize the gradually validated immense potential of collaborative immersive virtual environments (CIVEs) in higher education when designing and conducting geography lessons. These particular lessons focused on hypsography. ...

    Abstract The presented study aspires to utilize the gradually validated immense potential of collaborative immersive virtual environments (CIVEs) in higher education when designing and conducting geography lessons. These particular lessons focused on hypsography. A Research through Design approach and relevant qualitative methodology were used as we engaged two groups of domain experts (experienced geography teachers) to validate both the learning scenarios and the virtual environment we used. The lessons were administered via eDIVE—a novel platform for collaborative learning and teaching in virtual reality of our own design. The teachers underwent a hypsography virtual lesson and were randomly divided into two groups to be compared, which differed in the level of structure given to the lesson (one group received detailed instructions on what task they were to solve, while the other was given a free hand in exploring the environment and activities it afforded). The teachers’ experiences were then summarized in a post-lesson reflection and a subsequent focus group following the tasks. The participants’ expertise allowed insights to be gained into their first-hand experience as students, as well as their expert view of the lesson from an educational point of view. Virtual reality’s implementation into teaching practice was the key topic of the discussion.
    Keywords computer simulation ; focus groups ; geography ; qualitative analysis ; spatial data
    Language English
    Dates of publication 2022-0308
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article
    ZDB-ID 2655790-3
    ISSN 2220-9964
    ISSN 2220-9964
    DOI 10.3390/ijgi11030180
    Database NAL-Catalogue (AGRICOLA)

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