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Dolgopolovas V.,Vilnius University | Dolgopolovas V.,Vilniaus University of Applied Sciences | Dagien V.,Vilnius University | Minkevicius S.,Vilnius University | Sakalauskas L.,Vilnius University
Scientific Programming | Year: 2015

The aim of this study is to present an approach to the introduction into pipeline and parallel computing, using a model of the multiphase queueing system. Pipeline computing, including software pipelines, is among the key concepts in modern computing and electronics engineering. The modern computer science and engineering education requires a comprehensive curriculum, so the introduction to pipeline and parallel computing is the essential topic to be included in the curriculum. At the same time, the topic is among the most motivating tasks due to the comprehensive multidisciplinary and technical requirements. To enhance the educational process, the paper proposes a novel model-centered framework and develops the relevant learning objects. It allows implementing an educational platform of constructivist learning process, thus enabling learners' experimentation with the provided programming models, obtaining learners' competences of the modern scientific research and computational thinking, and capturing the relevant technical knowledge. It also provides an integral platform that allows a simultaneous and comparative introduction to pipelining and parallel computing. The programming language C for developing programming models and message passing interface (MPI) and OpenMP parallelization tools have been chosen for implementation. Copyright © 2015 Vladimiras Dolgopolovas et al. Source


Kazlauskaite-Jadzevice A.,Lithuanian Research Center for Agriculture and Forestry | Volungevicius J.,Vilnius University | Gregorauskiene V.,Lithuania Geological Survey | Marcinkonis S.,Vilniaus University of Applied Sciences
Journal of Environmental Engineering and Landscape Management | Year: 2014

The aim of this study to assess interdependence between urban soil pH and its accumulation of heavy metals. The article meant to be a contribution to a better knowledge of peculiarities and diagnostics of urban soil and its anthropogenic transformation. The hypothesis assumes that relationship between urban soil pH and its accumulation of heavy metals may be determined by the origin and age of parent material as well as the nature and degree of the anthropogenic impact. The spatial variability of topsoil pH level was performed in 100 points in eldership of Šnipiškes of the city Vilnius. Laboratory analysis was based on ISO 10390:2005. Samples were collected from 20 cm topsoil layer in the same sampling points where have been analysed concentrations of topsoil chemical elements using optical atomic emission spectrophotometry. The contamination of urban soils exhibits somewhat different compared to agricultural soils. In contradiction to earlier studies in Lithuanian agricultural soils where strong correlation between soil pH and Cr, Cd, Pb, Ni, Cu and Zd found, the conducted analysis shows a statistically reliable, but very weak (<0.3) correlation between the soil pH and concentration of contaminants. The proof to this correlation is provided by an existing relationship between pH and the concentration of copper (r = 0.20), mercury (r = 0.15), strontium (r = -0.12) and the overall contamination index (r = 0.12). The applied statistical analysis, however, failed to reveal the nature of interdependence between the soil pH and its contamination with studied heavy metals there concentration of contaminant chemical elements depends on the pH range of the soil and, conversely, the chemical reactivity of the soil changes affect on the concentration of studied chemical elements. Copyright © 2014 Vilnius Gediminas Technical University (VGTU) Press. Source


Mazeikiene A.,Vilnius University | Svediene S.,Vilniaus University of Applied Sciences
8th International Conference on Environmental Engineering, ICEE 2011 | Year: 2011

The aim of this paper was to investigate the performance parameters and efficiency of different sorbent materials (FIBROIL® and DUCK) for oil removal from aqueous mixtures and natural surface runoff water in dynamic mode. An experimental study was carried out. In all cases, pressure losses (in both sorbents filling) reached 25 cm point before petroleum products concentration of filtrate specimens reached 5 mg/L. The influence on filtering effectiveness had the filtering rate (the slower, the better effectiveness) and initial petroleum products concentration (the bigger inside research boundries, the better effectiveness). Both sorbent materials removed petroleum products from mixtures effecively (95,0 % - 99,7 %). DUCK was a little bit more effective than FIBROIL®, but it becomes foul more quickly. © Vilnius Gediminas Technical University, 2011. Source


Savulioniene L.,Vilnius University | Sakalauskas L.,Vilniaus University of Applied Sciences
Information Technology and Control | Year: 2014

Data mining is discovery of unknown, nontrivial, practically useful and easy to interpret knowledge in chaotic data. The information, found by application of data mining techniques, is unknown in advance. Knowledge is described by relationships of new features that distinguish one attribute value from other set attributes. The new knowledge set must be applied to new information with some degree of reliability. Current algorithms for finding association rules require several passes over the analysed database. The paper presents a stochastic algorithm for mining association rules in large data sets. Our stochastic algorithm reduces the database activity considerably, because the database is analysed only once. The algorithm allows us to measure two significant criteria, i.e. time and accuracy. We analyse a large database of transactions. Each transaction consists of items purchased by a customer in a visit. The algorithm yields conclusions about association rules using the analysis of randomly selected subsequences. Our experiments show that the proposed algorithm can find association rules efficiently in only one database scan. Source


Lopez-Aparicio S.,Norwegian Institute For Air Research | Grasiene R.,Vilniaus University of Applied Sciences
Journal of Environmental Engineering and Landscape Management | Year: 2013

Air pollution is a risk for human health and for the preservation of materials in particular cultural heritage objects. This paper presents the main results obtained in the project carried out by the Lithuanian Theatre, Music and Cinema Museum (LTMCM) and NILU-Norwegian Institute for Air Research. The main goal of the project was to perform a screening study and characterization of the indoor air pollution in the LTMCM. The results are used to assess the indoor air quality with regard to the preservation of cultural heritage objects therein. Measurement of NO2, organic acids (i.e. acetic and formic acids), photo-oxidant effects of the environment, climate (temperature and relative humidity) and particulate matter deposition were performed in different indoor locations. Low concentration of outdoor generated pollutants such as NO2 was found in storage rooms whereas higher concentrations were determined in the in the exhibition area. The results indicate that the building envelope does not protect effectively against infiltration of outdoor pollutants such as NO2 and particles. Very high concentration of indoor generated pollutants such as acetic acid was found in one storage room with a significant source. © 2013 Copyright Vilnius Gediminas Technical University (VGTU) Press. Source

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