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1. Sensitivity of European beech trees to unfavorable environmental factors on the edge and outside of their distribution range in northeastern Europe

Author

Augustaitis A, Kliučius A, Marozas V, Pilkauskas M, Augustaitiene I, Vitas A, Staszewski T, Jansons A, and Dreimanis A

Subjects
European Beech, Tree Increment Indexes, Meteorological Parameters, Ozone, Acidifying Compounds, Forestry, SD1-669.5
Abstract

European beech is a successful tree species outside its distribution range in northeastern Europe, where Prussian foresters introduced it mainly into Scots pine stands. This forest management practice resulted in new issues related to the sensitivity of European beech to current environmental changes in areas outside its natural range. We hypothesized that recent global environmental changes promoted the northeast migration of European beech outside its distribution range in Europe. To test this hypothesis, dendrochronological analysis of beech tree ring series was performed for eight sites located in Poland, Lithuania and Latvia. Frost in winter months and heat in June, along with drought in the vegetation period, limited beech tree growth outside its natural distribution range in northeast Europe. Higher air concentration of surface ozone and sulphur deposition level reinforced the negative effect of the detected key meteorological variables on beech growth, while higher air concentrations and deposition of nitrate had a positive effect. These factors explained about 50% of the total variation in increment indexes of beech trees at sites on the northeasren edge of their range. The observed trends of beech growth over the last 25 years has determined favorable conditions for planting this tree species outside its natural range in northeastern European forests.

Published
2016
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2. Dead wood quality influences species diversity of rare cryptogams in temperate broadleaved forests

Author

Preikša Z, Brazaitis G, Marozas V, and Jaroszewicz B

Subjects
Macrolichens, Fungi, Bryophytes, Tree Species, Indicator Species, Decay Stages, Forestry, SD1-669.5
Abstract

Dead wood is one of the most important indicators of forest naturalness and the most important manageable habitat for biodiversity in forests. Standing and lying dead wood, and especially coarse woody debris, plays an important part in creating habitats for many highly specialized organisms, e.g., insects, fungi, lichens and bacteria. Temperate mixed deciduous forests, rich in species, have been studied only to a small extent from the point of view of the ecology of wood-related cryptogams. Our study aimed at the reduction of the gap in knowledge about the ecological characteristics of dead wood-dependent organisms by focusing on species of cryptogams developing on various dead wood structures typical of temperate non-beech forests. Studies were performed in forests located in Lithuania, Poland, Belarus and Russia. We recorded 48 species of cryptogams: 18 species of bryophytes, 24 species of fungi and 6 species of lichens developing on dead wood. Our study stresses the importance of all types of dead wood as a substrate for the development of rare cryptogam species. Logs were the most important substratum type for cryptogams, followed by snags, dead trees and stumps. The cryptogam species richness on logs was several times higher than on the three other types of substrata. Coarse logs of intermediate decay stages hosted the highest number of cryptogams, followed by freshly fallen logs and, finally, well decayed logs. Assessing the importance of dead wood quality for the studied cryptogams, we found that intermediate decay stages are extremely important for fungi, while bryophytes or lichens do not show a clear preference. The highest number of cryptogams was found on Fraxinus excelsior, Quercus robur and Picea abies, while other tree species had less than half cryptogam species.

Published
2016
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3. Effects of planted European beech on the understory in Scots pine forests of Lithuania

Author

Marozas V, Augustaitis A, Armolaitis K, Kliucius A, and Pilkauskas M

Subjects
Non-native Tree Species, Fagus sylvatica, Litter, Pinus sylvestris, Soil, Species Richness, Vegetation, Vertical Structure, Forestry, SD1-669.5
Abstract

Understanding how the planting of non-native species impacts native vegetation is of most importance for forest management, as introduced species may alter environmental conditions with respect to soil composition, light intensity, and species composition. Here, we compared the stand structure, understory vegetation and site properties of a natural Scots pine (Pinus sylvestris L.) stand with Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.) as the second tree layer. We recorded saplings and species and their abundance in the understory vegetation, the thicknesses of organic (O) and humus (A) soil layers, soil pH and light indexes in nine Scots pine stands with a second tree layer of beech and in nine control pine stands with a second tree layer of spruce. An ordination method was used to analyze all the data together and ANOVA to determine whether there were differences between stands. We found that species diversity in pine stands with planted beech as the second layer was lower than in pine stands with spruce as the second layer. In pine stands with beech as the second tree layer, shrub, herb and moss cover was significantly lower, and the soil humus layer and organic soil layer were thicker and thinner, respectively. Stand parameters such as mean volume and mean annual increment of the second tree layer were significantly higher in pine stands with planted beech as the second tree layer than in pine stand with spruce as the second tree layer. The mean volume and the mean annual increment of the first tree layer dominated by Scots pine did not differ significantly between stands with planted beech and those with natural spruce. Scots pine stands with a beech second layer had negative effects on understory species richness and abundance. This effect was most likely due to the lower light transmittance and poor physical properties of the forest-floor litter in the Scots pine stands with planted beech.

Published
2014
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4. A fast screening approach for genetic tolerance to air pollution in Scots pine field tests

Author

Danusevičius D, Marozas V, Augustaitis A, and Plaušyte E

Subjects
Defoliation, Heritability, Pinus sylvestris, Radial Increment, Forestry, SD1-669.5
Abstract

This study aims to develop a screening approach for genetic tolerance to industrial pollution in Scots pine. The relationship between temporal variation in strength of genetic control on radial increment of seed orchard clones affected by air pollution and past pollutant emissions from a nitrogen fertilizer plant in central Lithuania was assessed. The annual radial increment was measured from increment cores. High present-day defoliation was associated to low radial increment during intensive pollution period in the years 1992 - 1995 when high defoliation was recorded in the stands. There was a tendency for a stronger genetic control of radial increment during the years of high defoliation. The clones representing the extremes of high and low radial increments during the stress period of 1992 - 1995 were selected for further tolerance testing based on needle anatomy traits.

Published
2013
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8. Where are we now with European forest multi-taxon biodiversity and where can we head to?

Author

Burrascano, S., Chianucci, F., Trentanovi, G., Kepfer-Rojas, S., Sitzia, T., Tinya, F., Doerfler, I., Paillet, Y., Nagel, T. A., Mitic, B., Morillas, L., Munzi, S., Van der Sluis, T., Alterio, E., Balducci, L., de Andrade, R. B., Bouget, C., Giordani, P., Lachat, T., Matosevic, D., Napoleone, F., Nascimbene, J., Paniccia, C., Roth, N., Aszalos, R., Brazaitis, G., Cutini, A., D'Andrea, E., De Smedt, P., Heilmann-Clausen, J., Janssen, P., Kozak, D., Marell, A., Mikolas, M., Norden, B., Matula, R., Schall, P., Svoboda, M., Ujhazyova, M., Vandekerkhove, K., Wohlwend, M., Xystrakis, F., Aleffi, M., Ammer, C., Archaux, F., Asbeck, T., Avtzis, D., Ayasse, M., Bagella, S., Balestrieri, R., Barbati, A., Basile, M., Bergamini, A., Bertini, G., Biscaccianti, A. B., Boch, S., Boloni, J., Bombi, P., Boscardin, Y., Brunialti, G., Bruun, H. H., Buscot, F., Byriel, D. B., Campagnaro, T., Campanaro, A., Chauvat, M., Ciach, M., Ciliak, M., Cistrone, L., Pereira, J. M. C., Daniel, R., De Cinti, B., De Filippo, G., Dekoninck, W., Di Salvatore, U., Dumas, Y., Elek, Z., Ferretti, F., Fotakis, D., Frank, T., Frey, J., Giancola, C., Gomoryova, E., Gosselin, M., Gosselin, F., Gossner, M. M., Gotmark, F., Haeler, E., Hansen, A. K., Hertzog, L., Hofmeister, J., Hosek, J., Johannsen, V. K., Justensen, M. J., Korboulewsky, N., Kovacs, B., Lakatos, F., Landivar, C. M., Lens, L., Lingua, E., Lombardi, F., Malis, F., Marchino, L., Marozas, V., Matteucci, G., Mattioli, W., Moller, P. F., Muller, J., Nemeth, C., Onodi, G., Parisi, F., Perot, T., Perret, S., Persiani, A. M., Portaccio, A., Posillico, M., Preiksa, Z., Rahbek, C., Rappa, N. J., Ravera, S., Romano, A., Samu, F., Scheidegger, C., Schmidt, I. K., Schwegmann, S., Sicuriello, F., Spinu, A. P., Spyroglou, G., Stillhard, J., Topalidou, E., Tottrup, A. P., Ujhazy, K., Veres, K., Verheyen, K., Weisser, W. W., Zapponi, L., and Odor, P.

Published
2023

11. Estimation of blurring of optic nerve disc margin

Author

Patašius, Martynas, Marozas, V., Jegelevičius, D., Daukantaitė, D., Lukoševičius, A., Magjarevic, R., editor, Nagel, J. H., editor, Vander Sloten, Jos, editor, Verdonck, Pascal, editor, Nyssen, Marc, editor, and Haueisen, Jens, editor

Published
2009
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17. Head-to-head comparison of single-lead and six-lead electrocardiography of a wrist-worn device for atrial fibrillation detection

Author

Bacevicius, J, primary, Taparauskaite, N, additional, Kundelis, R, additional, Abramikas, Z, additional, Pilkiene, A, additional, Dvinelis, E, additional, Staigyte, J, additional, Marinskiene, J, additional, Audzijoniene, D, additional, Petrylaite, M, additional, Jukna, E, additional, Jasiunas, E, additional, Marozas, V, additional, and Aidietis, A, additional

Published
2022
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18. Assessing hemodynamics from the photoplethysmogram to gain insights into vascular age: a review from VascAgeNet

Author

Charlton, P.H. Paliakaitė, B. Pilt, K. Bachler, M. Zanelli, S. Kulin, D. Allen, J. Hallab, M. Bianchini, E. Mayer, C.C. Terentes-Printzios, D. Dittrich, V. Hametner, B. Veerasingam, D. Žikić, D. Marozas, V.

Subjects
sense organs
Abstract

The photoplethysmogram (PPG) signal is widely measured by clinical and consumer devices, and it is emerging as a potential tool for assessing vascular age. The shape and timing of the PPG pulse wave are both influenced by normal vascular aging, changes in arterial stiffness and blood pressure, and atherosclerosis. This review summarizes research into assessing vascular age from the PPG. Three categories of approaches are described: 1) those which use a single PPG signal (based on pulse wave analysis), 2) those which use multiple PPG signals (such as pulse transit time measurement), and 3) those which use PPG and other signals (such as pulse arrival time measurement). Evidence is then presented on the performance, repeatability and reproducibility, and clinical utility of PPG-derived parameters of vascular age. Finally, the review outlines key directions for future research to realize the full potential of photoplethysmography for assessing vascular age.

Published
2022

19. Photoplethysmographic Waveform Analysis for Autonomic Reactivity Assessment in Depression

Author

Kontaxis S, Gil E, Marozas V, Lazaro J, Garcia E, Posadas-de Miguel M, Sara Siddi, Bernal ML, Aguilo J, Haro JM, De La Camara C, Laguna P, and Bailon R

Abstract

OBJECTIVE: In the present study, a photoplethysmographic (PPG) waveform analysis for assessing differences in autonomic reactivity to mental stress between patients with Major Depressive Disorder (MDD) and healthy control (HC) subjects is presented. METHODS: PPG recordings of 40 MDD and 40 HC subjects were acquired at basal conditions, during the execution of cognitive tasks, and at the post-task relaxation period. PPG pulses are decomposed into three waves (a main wave and two reflected waves) using a pulse decomposition analysis. Pulse waveform characteristics such as the time delay between the position of the main wave and reflected waves, the percentage of amplitude loss in the reflected waves, and the heart rate (HR) are calculated among others. The intra-subject difference of a feature value between two conditions is used as an index of autonomic reactivity. RESULTS: Statistically significant individual differences from stress to recovery were found for HR and the percentage of amplitude loss in the second reflected wave ( A(13)) in both HC and MDD group. However, autonomic reactivity indices related to A(13) reached higher values in HC than in MDD subjects (Cohen's d =0.81, AUC = 0.74), implying that the stress response in depressed patients is reduced. A statistically significant (p < 0.001) negative correlation (r = 0.5) between depression severity scores and A(13) was found. CONCLUSION: A decreased autonomic reactivity is associated with higher degree of depression. SIGNIFICANCE: Stress response quantification by dynamic changes in PPG waveform morphology can be an aid for the diagnosis and monitoring of depression.

Published
2021

20. Current Wildland Fire Patterns and Challenges in Europe: A Synthesis of National Perspectives

Author

Fernandez-Anez, N., Krasovskiy, A., Müller, M., Vacik, H., Baetens, J., Hukić, E., Kapovic Solomun, M., Atanassova, I., Glushkova, M., Bogunović, I., Fajković, H., Djuma, H., Boustras, G., Adámek, M., Devetter, M., Hrabalikova, M., Huska, D., Martínez Barroso, P., Vaverková, M.D., Zumr, D., Jõgiste, K., Metslaid, M., Koster, K., Köster, E., Pumpanen, J., Ribeiro-Kumara, C., Di Prima, S., Pastor, A., Rumpel, C., Seeger, M., Daliakopoulos, I., Daskalakou, E., Koutroulis, A., Papadopoulou, M.P., Stampoulidis, K., Xanthopoulos, G., Aszalós, R., Balázs, D., Kertész, M., Valkó, O., Finger, D.C., Thorsteinsson, T., Till, J., Bajocco, S., Gelsomino, A., Amodio, A.M., Novara, A., Salvati, L., Telesca, L., Ursino, N., Jansons, A., Kitenberga, M., Stivrins, N., Brazaitis, G., Marozas, V., Cojocaru, O., Gumeniuc, I., Sfecla, V., Imeson, A., Veraverbeke, S., Mikalsen, R.F., Koda, Eu., Osinski, P., Castro, A.C. M., Nunes, J.P., Oom, D., Vieira, D., Rusu, T., Bojović, S., Djordjevic, D., Popovic, Z., Protic, M., Sakan, S., Glasa, J., Kacikova, D., Lichner, L., Majlingova, A., Vido, J., Ferk, M., Tičar, J., Zorn, M., Zupanc, V., Hinojosa, M., Knicker, H., Lucas-Borja, M.E., Pausas, J., Prat-Guitart, N., Ubeda, X., Vilar, L., Destouni, G., Ghajarnia, N., Kalantari, Z., Seifollahi-Aghmiuni, S., Dindaroglu, T., Yakupoglu, T., Smith, T., Doerr, S., Cerda, A., Fernandez-Anez, N., Krasovskiy, A., Müller, M., Vacik, H., Baetens, J., Hukić, E., Kapovic Solomun, M., Atanassova, I., Glushkova, M., Bogunović, I., Fajković, H., Djuma, H., Boustras, G., Adámek, M., Devetter, M., Hrabalikova, M., Huska, D., Martínez Barroso, P., Vaverková, M.D., Zumr, D., Jõgiste, K., Metslaid, M., Koster, K., Köster, E., Pumpanen, J., Ribeiro-Kumara, C., Di Prima, S., Pastor, A., Rumpel, C., Seeger, M., Daliakopoulos, I., Daskalakou, E., Koutroulis, A., Papadopoulou, M.P., Stampoulidis, K., Xanthopoulos, G., Aszalós, R., Balázs, D., Kertész, M., Valkó, O., Finger, D.C., Thorsteinsson, T., Till, J., Bajocco, S., Gelsomino, A., Amodio, A.M., Novara, A., Salvati, L., Telesca, L., Ursino, N., Jansons, A., Kitenberga, M., Stivrins, N., Brazaitis, G., Marozas, V., Cojocaru, O., Gumeniuc, I., Sfecla, V., Imeson, A., Veraverbeke, S., Mikalsen, R.F., Koda, Eu., Osinski, P., Castro, A.C. M., Nunes, J.P., Oom, D., Vieira, D., Rusu, T., Bojović, S., Djordjevic, D., Popovic, Z., Protic, M., Sakan, S., Glasa, J., Kacikova, D., Lichner, L., Majlingova, A., Vido, J., Ferk, M., Tičar, J., Zorn, M., Zupanc, V., Hinojosa, M., Knicker, H., Lucas-Borja, M.E., Pausas, J., Prat-Guitart, N., Ubeda, X., Vilar, L., Destouni, G., Ghajarnia, N., Kalantari, Z., Seifollahi-Aghmiuni, S., Dindaroglu, T., Yakupoglu, T., Smith, T., Doerr, S., and Cerda, A.

Abstract

Changes in climate, land use, and land management impact the occurrence and severity of wildland fires in many parts of the world. This is particularly evident in Europe, where ongoing changes in land use have strongly modified fire patterns over the last decades. Although satellite data by the European Forest Fire Information System provide large-scale wildland fire statistics across European countries, there is still a crucial need to collect and summarize in-depth local analysis and understanding of the wildland fire condition and associated challenges across Europe. This article aims to provide a general overview of the current wildland fire patterns and challenges as perceived by national representatives, supplemented by national fire statistics (2009–2018) across Europe. For each of the 31 countries included, we present a perspective authored by scientists or practitioners from each respective country, representing a wide range of disciplines and cultural backgrounds. The authors were selected from members of the COST Action “Fire and the Earth System: Science & Society” funded by the European Commission with the aim to share knowledge and improve communication about wildland fire. Where relevant, a brief overview of key studies, particular wildland fire challenges a country is facing, and an overview of notable recent fire events are also presented. Key perceived challenges included (1) the lack of consistent and detailed records for wildland fire events, within and across countries, (2) an increase in wildland fires that pose a risk to properties and human life due to high population densities and sprawl into forested regions, and (3) the view that, irrespective of changes in management, climate change is likely to increase the frequency and impact of wildland fires in the coming decades. Addressing challenge (1) will not only be valuable in advancing national and pan-European wildland fire management strategies, but also in evaluating perceptions (2) and (3

Published
2021

25. Abundant non-native tree species in Europe: traits and effects on ecosystems

Author

Wohlgemuth, T., Brundu, G., Castro-Díez, P., Campagnaro, T., Dobrowolska, D., Essl, F., Gazda, A., Gossner, M. M., Keren, S., Keresu, Z., Knüsel, S., Koprowski, M., La Porta, N., Marchante, H., Marozas, V., Nygaard, P. H., Podrázský, V., Puchalka, R., Reisman-Berman, O., Silva, J. S., Straigyte, L., Vacchiano, G., Van Loo, M., Ylioja, T., and Pötzelsberger, E.

Published
2018

28. ABIOTIC STRESS IMPACT ON AEROSOL MASS SPECTRA OVER A FOREST SITE IN LITHUANIA.

Author

Pauraitė, J., Byčenkienė, S., Plauškaitė, K., Augustaitis, A., Marozas, V., Mozgeris, G., Pivoras, A., Pivoras, G., and Ulevičius, V.

Subjects
MASS spectrometry, ATMOSPHERIC aerosols, AEROSOLS, TREE trunks, CHEMICAL speciation, ABIOTIC stress
Abstract

Copyright of Lithuanian Journal of Physics is the property of Lithuanian Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2019
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29. Noise resistant method for cardiac pulse wave arrival time estimation

Author

Rapalis, A., Janusauskas, A., Lukosevicius, A., Marozas, V., and Kauno technologijos universitetas

Subjects
Noise (signal processing), Acoustics, electrocardiography, Real-time computing, Pulse duration, orthostatic test, Instantaneous phase, Signal, Pulse (physics), Signal-to-noise ratio, Photoplethysmogram, pulse wave arrival time, Pulse wave, photoplethysmography, Electrical and Electronic Engineering, Mathematics
Abstract

Pulse arrival time is the time interval which is needed for pulse wave to travel the distance from the heart to some distal place on the body. Almost all definitions of pulse arrival time estimation are based on high quality photoplethysmogram signals. However, when subject movement is involved movement artifacts dominate in the signal, e.g., records from orthostatic test, and estimation of pulse arrival time becomes complicated. The aim of this study is to present pulse arrival time estimation method which is based on instantaneous phase shift estimation between extracted fundamental frequency components and compare it with a classical method which based on photoplethysmogram signal derivative maximum. The results showed that the proposed method is better for pulse arrival time estimation when signals are noisy. The method yielded pulse arrival time with the highest agreement, accuracy, precision and lowest variability. There is high intraclass correlation when signal to noise ratio are 0 dB and 10 dB (0.5317 and 0.8630). The classical method incorrectly estimates pulse arrival time when are using real signals. However, larger dataset is needed in order to get statistically significant results. Variability of pulse arrival time and arterial blood pressure is higher in the vertical posture. DOI: http://dx.doi.org/10.5755/j01.eee.20.8.8442

Published
2014

30. Limb’s vibrations exercise monitoring with MEMS accelerometer to identify influence of cardiovascular system

Author

Venslauskas, M., Ostasevičius, V., and Marozas, V.

Subjects
physiological parameters, cardiovascular system, blood circulation, blood flow rate, MEMS accelerometer
Abstract

Katsuzo Nishi in 1927 proposed the capillarity exercise based on limbs vibrations to compensate obstruction of blood circulation. Research was made to identify influence of vibrations to human's physiological parameters. There were made an exercise regarding to Nishi methodology and imitation of exercise with one arm on vibration stand while monitoring physiological parameters and accelerations. Detected parameters' changes were significantly smaller when vibrating only one hand. Future plans are to imitate exercise while vibrating all limbs and make a stand to imitate cardiovascular system to identify vibrations influence in blood flow rate.

Published
2013

31. AEROSOL PARTICLE FORMATION IN THE LITHUANIAN HEMI-BOREAL FOREST.

Author

Dudoitis, V., Mordas, G., Byčenkienė, S., Plauškaitė, K., Pauraitė, J., Jasinevičienė, D., Marozas, V., Pivoras, G., Mozgeris, G., Augustaitis, A., and Ulevičius, V.

Subjects
ATMOSPHERIC aerosols, TAIGAS, AIR quality, NUCLEATION, CONDENSATION
Abstract

Copyright of Lithuanian Journal of Physics is the property of Lithuanian Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2018
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32. Motivating the students to study the basics of digital signal processing by using virtual learning environment

Author

Marozas, V., Dumbrava, V., and Kauno technologijos universitetas

Subjects
ComputingMilieux_COMPUTERSANDEDUCATION
Abstract

The course “Discrete time signal processing” might seem for students as being quite theoretical and difficult to understand. We have introduced several innovations into the course at the beginning of the year 2008. This paper describes the experience in teaching the basics of discrete signal processing by using MATLAB based projects involving synthesis, processing and analysis of sounds as well as the variety of tools available in virtual learning environment. It is well known that information and knowledge is grasped easier if more senses are activated during the learning process. Thus several lab works were designed with the goal to synthesize the sound of the bell, to design the digital reverberator, to analyze the noise of computer ventilators and others. Modern virtual learning environments (Moodle, WebCT) are usually used mere as depositories of learning materials. In our case, we used almost all the tools available in the virtual learning environment including: assessments, assignments, discussion forums, electronic submission of lab reports, announcements and usage statistics reports as the teacher tool. The anonymous course evaluation results by the students are presented in the final part of the paper., Diskretinių signalų apdorojimo kursas studentams gali atrodyti grynai teorinis ir sunkiai suprantamas, todėl nuo 2008 metų pradžios į tokį kursą esame įdiegę keletą naujovių. Aprašytas diskretinių signalų apdorojimo pagrindų mokymas naudojant MATLAB programinę įrangą ir terpę, kurioje panaudota virtualių mokymosi aplinkų įvairovė, taikant sintezės, garsinių signalų apdorojimo ir analizės priemones. Gerai žinoma, kad informacija ir žinios įsisavinamos lengviau, jei mokymosi procese aktyvuojama kuo daugiau pojūčių. Taigi, buvo sukurti keli laboratoriniai darbai, kurių viename sintezuojamas varpo garsas, kitas buvo skirtas skaitmeninio reverberatoriaus darbui modeliuoti, trečiasis darbas skirtas kompiuterių ventiliatorių keliamo triukšmo analizei. Šiuolaikinės virtualios mokymosi terpės (Moodle, WebCT) paprastai naudojamos tik kaip mokymosi medžiagos saugykla. Šiame darbe panaudoti beveik visi virtualios mokymosi aplinkos įrankiai, įskaitant užduočių vertinimą, diskusijų forumus, elektroniniu būdu pateiktus laboratorinių tyrimų rezultatus, pranešimus ir studentų aktyvumo statistikos ataskaitas kaip dėstytojo kontrolės priemonę. Baigiamojoje straipsnio dalyje pateikti anoniminiai studentų kurso vertinimo rezultatai.

Published
2010

33. Modification of method for drusen detection in eye fundus images

Author

Patašius, M., Marozas, V., Jegelevičius, D., Lukoševičius, A., Spečkauskas, M., and Kauno technologijos universitetas

Subjects
Optic disk drusen | Diagnosis, genetic structures, Fundus oculi | Radiography, sense organs, eye diseases
Abstract

Drusen are white or yellow spots in eye fundus that consist of extracellular material. They are a sign of age-related macular degeneration (AMD) – the main cause of blindness in the developed countries and a third main cause of blindness in the whole world. Previously a drusen detection method based on optimized colour combinations has been proposed, but it has only been investigated empirically. Thus here this method is investigated using one-dimensional and two-dimensional models of drusen, its properties are found and improvements suggested., Drūzos – tai baltos ar geltonos dėmės akies dugne, susidedančios iš tarpląstelinės medžiagos. Jos yra vienas iš amžinės makulos degeneracijos (AMD) simptomų. AMD yra dažniausia aklumo priežastis išsivysčiusiose šalyse ir trečia pagal dažnumą pasauliniu mastu. Anksčiau pasiūlytas drūzų paieškos metodas rėmėsi optimizuotomis spalvų kombinacijomis. Tačiau tada jis buvo tiriamas tik empiriškai. Šiame straipsnyje minėtas metodas ištirtas naudojant vienmačius ir dvimačius drūzų modelius, nustatytos metodo savybės ir pasiūlyta patobulinimų.

Published
2010

34. Synthesis of parametric map from raw ultrasound B-Scan data

Author

Jurkonis, R., Daukantas, S., Janušauskas, A., Lukoševičius, A., Marozas, V., Jegelevičius, D., and Kauno technologijos universitetas

Abstract

There are presented results of ultrasound radio-frequency signal sampling and processing to synthesize B-scan maps and evaluate two-dimensional visualization of ultrasound signal parameters. Our source of signal was ultrasound echoscope Mentor AdventTM A/B with mechanical scanning transducer of 11 MHz. Radio-frequency signal was digitized with digitizer Picoscope 5203. Amplitude and frequency based parameters were used for mapping B-scan ultrasound images. Standard phantom with axial resolution targets was used for the evaluation of mapping performance. We conclude that the signal processing and image transformation implemented in Matlab programs provide adequate two-dimensional mapping of B-scans. The usage of mean instantaneous bandwidth of radio frequency echoscopic signals enables to improve lateral resolution., Pateikiami ultragarsinių radijo dažninių signalų skaitmeninimo ir apdorojimo rezultatai siekiant sintezuoti B skenavimo vaizdus ir įvertinti dvimatį ultragarsinių signalų parametrų vaizdavimą. Signalo šaltinis buvo ultragarsinė echoskopinė sistema Mentor AdventTM A/B su 11 MHz mechaninio skenavimo keitikliu. Radijo dažninis signalas buvo skaitmenintas skaitmenikliu Picoscope 5203. Įvertintos dvimačio vaizdavimo galimybės tiriant išilginio skiriamumo taikinius standartiniame fantome. B skenavimo vaizduose parodytos ne tik amplitudinės, bet ir dažninės echosignalo savybės. Šis tyrimas parodė, kad apdorojant signalus ir transformuojant vaizdus Matlab terpėje galima gauti adekvačius dvimačius B skenavimo vaizdus. Naudojant radijo dažninio echoskopinio signalo vidutinį momentinį juostos plotį, galima pagerinti skersinį skiriamumą.

Published
2009

35. Optimal combinations of color space components for detection of blood vessels in eye fundus images

Author

Patašius, M., Marozas, V., Jegelevičius, D., Lukoševičius, A., and Kauno technologijos universitetas

Abstract

Most of the studies so far have used the green component of RGB for blood vessel recognition in eye fundus images with some using luminance. However, the suitableness of such choice and possible alternatives have not been sufficiently explored. We aimed to find the linear color combinations that would be optimal for classification of the eye fundus image pixels. It has been shown that the use of color combination optimized for “local” classification instead of green color improves results of the segmentation algorithm and retains the quality of results of tracing algorithm, while color combinations optimized for “global” and “superglobal” classification improve the sensitivity of segmentation algorithm at the price of specificity. The results indicate possibility of developing blood vessel detection algorithms that would combine advantages of different color combinations., Kraujagyslėms aptikti daugumoje tyrimų iki šiol naudojamas žalias RGB spalvų erdvės komponentas. Kitais atvejais naudojamas skaistis. Tačiau tokio pasirinkimo tikslingumas ir galimos alternatyvos dar nebuvo reikiamai išnagrinėta. Šiame straipsnyje siekiama rasti tiesines spalvų kombinacijas, kurios optimaliai tiktų akies dugno vaizdų pikseliams klasifikuoti. Paaiškėjo, kad spalvų kombinacijos, optimizuotos „lokaliai“ klasifikacijai, pagerina išbandyto segmentavimo algoritmo darbo rezultatus ir išlaiko trasavimo algoritmo rezultatų kokybę. O „globaliai“ ir „superglobaliai“ klasifikacijai optimizuotos spalvų kombinacijos padidina segmentavimo algoritmo jautrumą specifiškumo sąskaita. Šie rezultatai leidžia tikėtis, kad įmanoma sukurti kraujagyslių radimo algoritmus, išnaudojančius skirtingų spalvų kombinacijų pranašumus.

Published
2009

36. Development of virtual and remote lab experimentation system for electronics engineering

Author

Marozas, V., Jurkonis, R., Lukoševičius, A., and Kauno technologijos universitetas

Subjects
system design, mokslinis tyrimas, biomedical engineering, scientific surveys, electronics, elektronika, sistemų projektavimas, biomedicininė inžinerija
Abstract

The aim is to present the implementation approach of on-site and remote experimenting systems for several usage scenarious: basic mastering of concepts in electronics education (simulation experiments), specialised experiments or real life solutions in, for example, biomedical engineering and scientific research. All the experimenting systems are built as virtual instruments i.e. they integrate standard computer, specialized software developed in LabView and additional periphery devices: digitizer (Picoscope ADC 212/100, Picotech Ltd.), function generator (Hameg HM8131-2, Hameg Instruments GmbH), analog directional Doppler device (806-C, Parks Electronics Inc.), ultrasound transducers, and real objects under investigation. The students will improve their knowledge of development of modern systems using our problem oriented experimenting systems, which are modular, flexible and expandable., Pateikiama keletas lokalių ir nutolusių eksperimentavimo sistemų keletui vartojimo scenarijų: elektronikos mokslų baziniams gebėjimams ugdyti (imitavimo eksperimentai), specializuotiems ir realiems eksperimentams atlikti, pavyzdžiui, biomedicininėje inžinerijoje ir moksliniuose tyrimuose. Visos eksperimentavimo sistemos yra įgyvendintos kaip virtualūs instrumentai, t. y. jungia standartinį kompiuterį su specializuota LabView paketu sukurta programine įranga ir papildomais periferiniais prietaisais: skaitmeniniu keitikliu (Picoscope ADC 212/100, Picotech Ltd.), funkcijų generatoriumi (Hameg HM8131-2, Hameg Instruments GmbH), analoginiu Doplerio prietaisu (806-C, Parks Electronics Inc.) ultragarsiniais keitikliais ir realiais tiriamaisiais objektais. Studentai, eksperimentuodami su mūsų sukurtomis į problemas orientuotomis sistemomis, ugdys savo gebėjimus kurti šiuolaikines modulines, lanksčias ir išplečiamas sistemas.

Published
2008

37. Courseware for ultrasonic medical diagnostics curriculum: system for on-site and remote laboratory experiments

Author

Jurkonis, R., Marozas, V., Lukoševičius, A., and Kauno technologijos universitetas

Subjects
on-site laboratory, medical diagnostics, ultrasound, LabView, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, ultragarsas, remote laboratory, diagnostika
Abstract

The aim of this paper is to present the implementation approach of on-site and remote experimenting laboratory for ultrasound medical diagnostics curriculum. We demonstrate the implementation of such laboratory using virtual instrument that is built by using a standard computer, a ultrasonic transducer with a tissue like phantom, digitizer, function generator and the software package LabView. By controlling the virtual instrument it is possible to excite and receive ultrasound waves in the pulse echo mode, then process the received echographic signal and get the characteristics of the tissue like phantom. The tissue like phantom is characterized with thickness and density also with the speed of wave's propagation and attenuation coefficient. The students are motivated by the assignment of the precise task - to identify the material from which the phantom is made. The implemented on-site experiments system is based on a virtual instrument, the remote experiments system and is tested using the LabView remote panel technology as well. This technology allows accessing the experiment system remotely using an internet browser. We expect the students will improve their knowledge of ultrasound medical diagnostics using our hands-on lab experiment system., Darbo tikslas - vadovaujantis eksperimentinio mokymosi koncepcija sukurti ir įdiegti prototipinę laboratorinių eksperimentų sistemą į audinius panašioms medžiagoms apibūdinti. Metodai. Laboratorinių eksperimentų sistemai įdiegti taikomos modernios elektroninio mokymosi technologijos, prototipinė sistema realizuota LabView virtualiųjų instrumentų ir mokymosi kurso valdymo aplinkos Moodle principais. Didėjantis ultragarsinių diagnostinių tyrimų poreikis, kai įvertinama kiekybinė informacija apie audinius, taip pat populiarėjanti ultragarsinė technologija medicinos praktikoje paskatino įdiegti modernią mokymosi sistemą biomedicininės inžinerijos studentams. Tuo siekiama jiems suteikti adekvačių ir modernių ultragarsinės technologijos taikymo medicinoje žinių. [...].

Published
2008

43. Network based clinical decision support system

Author

Jegelevicius, D., primary, Krisciukaitis, A., additional, Lukosevicius, A., additional, Marozas, V., additional, Paunksnis, A., additional, Barzdziukas, V., additional, Patasius, M., additional, Buteikiene, D., additional, Vainoras, A., additional, and Gargasas, L., additional

Published
2009
Full Text
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47. How New and Evolving Biomedical Engineering Programs Benefit from EVICAB project.

Author

Jarm, Tomaz, Kramar, Peter, Zupanic, Anze, Lukosevicius, Arunas, and Marozas, V.

Abstract

Problems of new and evolving Biomedical Engineering (BME) programs in European universities are collated with the opportunities and benefits offered by the EVICAB project. Benefits of European Virtual Campus for Biomedical Engineering (EVICAB) for new course developers, administrators, teachers and students are presented and illustrated by examples. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
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