Topalović, Dušan

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  • Topalović, Dušan (4)

Author's Bibliography

In search of an optimal in-field calibration method of low-cost gas sensors for ambient air pollutants: Comparison of linear, multilinear and artificial neural network approaches

Topalović, Dušan; Davidović, Miloš D.; Jovanović, Maja; Bartonova, Alena; Ristovski, Zoran; Jovašević-Stojanović, Milena

(2019)

TY  - JOUR
AU  - Topalović, Dušan
AU  - Davidović, Miloš D.
AU  - Jovanović, Maja
AU  - Bartonova, Alena
AU  - Ristovski, Zoran
AU  - Jovašević-Stojanović, Milena
PY  - 2019
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/8372
AB  - The current compliance networks of automatic air-quality monitoring stations in large urban environments are not sufficient to provide spatial and temporal measurement resolution for realistic assessment of personal exposure to pollutants. Small low-cost sensor platforms with greater mobility and expected lower maintenance costs, are increasingly being used as a supplement to compliance monitoring stations. However, low-cost sensor platforms usually provide data with uncertain precision. To improve the precision, these sensor platforms require in-field calibration. Our paper aims to demonstrate that data from each individual sensor system can be corrected using that sensor system's own data to achieve much improved data quality compared to a reference. However, in this procedure, there are practical difficulties such as individual sensor outputs from the multi-sensor system not being sufficiently available due to malfunctions for instance. We explore how this can be dealt with. In our opinion, this is a novel approach, of practical importance both to users and manufacturers. We present a detailed comparative analysis of Linear Regression (univariate), Multivariate Linear Regression and Artificial Neural Networks used with a specific aim of calibrating field-deployed low-cost CO and O3 sensors. For Artificial Neural Network models, the performance of three common training algorithms was compared (Levenberg-Marquardt, Resilient back-propagation and Conjugate Gradient Powell-Beale algorithm). Data for this study were obtained from two campaigns conducted with 25 multi-sensor AQMESH v.3.5 platforms used within the activities of the CITI-SENSE project. The platforms were co-located to reference gas monitors at the Automatic Monitoring Station Stari Grad, in Belgrade, Serbia. This paper demonstrates that Multivariate Linear Regression and Artificial Neural Network calibration models can improve the output signal. This improvement can be measured by changes in the median and interquartile ranges of statistical parameters used for model evaluation. Artificial Neural Networks showed the best results compared to Linear Regression and Multivariate Linear Regression models. The best predictors for CO, in addition to CO low-cost sensor data, were PM2.5 and NO2, while for O3, in addition to O3 low-cost sensor data, the most suitable input predictors were NO and aH. Based on residual error analysis, we have shown that for CO and O3, a certain range of concentrations exists in which calibrated values differ by less than 10% from the reference method results. In addition, it was noted that for all models, CO sensors consistently showed lower variability between platforms compared to O3 sensors. © 2019 Elsevier Ltd
T2  - Atmospheric Environment
T1  - In search of an optimal in-field calibration method of low-cost gas sensors for ambient air pollutants: Comparison of linear, multilinear and artificial neural network approaches
VL  - 213
SP  - 640
EP  - 658
DO  - 10.1016/j.atmosenv.2019.06.028
ER  - 
@article{
author = "Topalović, Dušan and Davidović, Miloš D. and Jovanović, Maja and Bartonova, Alena and Ristovski, Zoran and Jovašević-Stojanović, Milena",
year = "2019",
abstract = "The current compliance networks of automatic air-quality monitoring stations in large urban environments are not sufficient to provide spatial and temporal measurement resolution for realistic assessment of personal exposure to pollutants. Small low-cost sensor platforms with greater mobility and expected lower maintenance costs, are increasingly being used as a supplement to compliance monitoring stations. However, low-cost sensor platforms usually provide data with uncertain precision. To improve the precision, these sensor platforms require in-field calibration. Our paper aims to demonstrate that data from each individual sensor system can be corrected using that sensor system's own data to achieve much improved data quality compared to a reference. However, in this procedure, there are practical difficulties such as individual sensor outputs from the multi-sensor system not being sufficiently available due to malfunctions for instance. We explore how this can be dealt with. In our opinion, this is a novel approach, of practical importance both to users and manufacturers. We present a detailed comparative analysis of Linear Regression (univariate), Multivariate Linear Regression and Artificial Neural Networks used with a specific aim of calibrating field-deployed low-cost CO and O3 sensors. For Artificial Neural Network models, the performance of three common training algorithms was compared (Levenberg-Marquardt, Resilient back-propagation and Conjugate Gradient Powell-Beale algorithm). Data for this study were obtained from two campaigns conducted with 25 multi-sensor AQMESH v.3.5 platforms used within the activities of the CITI-SENSE project. The platforms were co-located to reference gas monitors at the Automatic Monitoring Station Stari Grad, in Belgrade, Serbia. This paper demonstrates that Multivariate Linear Regression and Artificial Neural Network calibration models can improve the output signal. This improvement can be measured by changes in the median and interquartile ranges of statistical parameters used for model evaluation. Artificial Neural Networks showed the best results compared to Linear Regression and Multivariate Linear Regression models. The best predictors for CO, in addition to CO low-cost sensor data, were PM2.5 and NO2, while for O3, in addition to O3 low-cost sensor data, the most suitable input predictors were NO and aH. Based on residual error analysis, we have shown that for CO and O3, a certain range of concentrations exists in which calibrated values differ by less than 10% from the reference method results. In addition, it was noted that for all models, CO sensors consistently showed lower variability between platforms compared to O3 sensors. © 2019 Elsevier Ltd",
journal = "Atmospheric Environment",
title = "In search of an optimal in-field calibration method of low-cost gas sensors for ambient air pollutants: Comparison of linear, multilinear and artificial neural network approaches",
volume = "213",
pages = "640-658",
doi = "10.1016/j.atmosenv.2019.06.028"
}
Topalović, D., Davidović, M. D., Jovanović, M., Bartonova, A., Ristovski, Z.,& Jovašević-Stojanović, M.. (2019). In search of an optimal in-field calibration method of low-cost gas sensors for ambient air pollutants: Comparison of linear, multilinear and artificial neural network approaches. in Atmospheric Environment, 213, 640-658.
https://doi.org/10.1016/j.atmosenv.2019.06.028
Topalović D, Davidović MD, Jovanović M, Bartonova A, Ristovski Z, Jovašević-Stojanović M. In search of an optimal in-field calibration method of low-cost gas sensors for ambient air pollutants: Comparison of linear, multilinear and artificial neural network approaches. in Atmospheric Environment. 2019;213:640-658.
doi:10.1016/j.atmosenv.2019.06.028 .
Topalović, Dušan, Davidović, Miloš D., Jovanović, Maja, Bartonova, Alena, Ristovski, Zoran, Jovašević-Stojanović, Milena, "In search of an optimal in-field calibration method of low-cost gas sensors for ambient air pollutants: Comparison of linear, multilinear and artificial neural network approaches" in Atmospheric Environment, 213 (2019):640-658,
https://doi.org/10.1016/j.atmosenv.2019.06.028 . .
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Confined electron states in two-dimensional HgTe in magnetic field: Quantum dot versus quantum ring behavior

Topalović, Dušan; Arsoski, Vladimir; Tadić, Milan Ž.; Peeters, François M.

(2019)

TY  - JOUR
AU  - Topalović, Dušan
AU  - Arsoski, Vladimir
AU  - Tadić, Milan Ž.
AU  - Peeters, François M.
PY  - 2019
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/8534
AB  - We investigate the electron states and optical absorption in square- and hexagonal-shaped two-dimensional (2D) HgTe quantum dots and quantum rings in the presence of a perpendicular magnetic field. The electronic structure is modeled by means of the sp3d5s∗ tight-binding method within the nearest-neighbor approximation. Both bulklike and edge states appear in the energy spectrum. The bulklike states in quantum rings exhibit Aharonov-Bohm oscillations in magnetic field, whereas no such oscillations are found in quantum dots, which is ascribed to the different topology of the two systems. When magnetic field varies, all the edge states in square quantum dots appear as quasibands composed of almost fully flat levels, whereas some edge states in quantum rings are found to oscillate with magnetic field. However, the edge states in hexagonal quantum dots are localized like in rings. The absorption spectra of all the structures consist of numerous absorption lines, which substantially overlap even for small line broadening. The absorption lines in the infrared are found to originate from transitions between edge states. It is shown that the magnetic field can be used to efficiently tune the optical absorption of HgTe 2D quantum dot and quantum ring systems. © 2019 American Physical Society.
T2  - Physical Review B
T1  - Confined electron states in two-dimensional HgTe in magnetic field: Quantum dot versus quantum ring behavior
VL  - 100
IS  - 12
SP  - 125304
DO  - 10.1103/PhysRevB.100.125304
ER  - 
@article{
author = "Topalović, Dušan and Arsoski, Vladimir and Tadić, Milan Ž. and Peeters, François M.",
year = "2019",
abstract = "We investigate the electron states and optical absorption in square- and hexagonal-shaped two-dimensional (2D) HgTe quantum dots and quantum rings in the presence of a perpendicular magnetic field. The electronic structure is modeled by means of the sp3d5s∗ tight-binding method within the nearest-neighbor approximation. Both bulklike and edge states appear in the energy spectrum. The bulklike states in quantum rings exhibit Aharonov-Bohm oscillations in magnetic field, whereas no such oscillations are found in quantum dots, which is ascribed to the different topology of the two systems. When magnetic field varies, all the edge states in square quantum dots appear as quasibands composed of almost fully flat levels, whereas some edge states in quantum rings are found to oscillate with magnetic field. However, the edge states in hexagonal quantum dots are localized like in rings. The absorption spectra of all the structures consist of numerous absorption lines, which substantially overlap even for small line broadening. The absorption lines in the infrared are found to originate from transitions between edge states. It is shown that the magnetic field can be used to efficiently tune the optical absorption of HgTe 2D quantum dot and quantum ring systems. © 2019 American Physical Society.",
journal = "Physical Review B",
title = "Confined electron states in two-dimensional HgTe in magnetic field: Quantum dot versus quantum ring behavior",
volume = "100",
number = "12",
pages = "125304",
doi = "10.1103/PhysRevB.100.125304"
}
Topalović, D., Arsoski, V., Tadić, M. Ž.,& Peeters, F. M.. (2019). Confined electron states in two-dimensional HgTe in magnetic field: Quantum dot versus quantum ring behavior. in Physical Review B, 100(12), 125304.
https://doi.org/10.1103/PhysRevB.100.125304
Topalović D, Arsoski V, Tadić MŽ, Peeters FM. Confined electron states in two-dimensional HgTe in magnetic field: Quantum dot versus quantum ring behavior. in Physical Review B. 2019;100(12):125304.
doi:10.1103/PhysRevB.100.125304 .
Topalović, Dušan, Arsoski, Vladimir, Tadić, Milan Ž., Peeters, François M., "Confined electron states in two-dimensional HgTe in magnetic field: Quantum dot versus quantum ring behavior" in Physical Review B, 100, no. 12 (2019):125304,
https://doi.org/10.1103/PhysRevB.100.125304 . .
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An evaluation tool kit of air quality micro-sensing units

Fishbain, Barak; Lerner, Uri; Castell, Nuria; Cole-Hunter, Tom; Popoola, Olalekan; Broday, David M.; Martinez Iniguez, Tania; Nieuwenhuijsen, Mark; Jovašević-Stojanović, Milena; Topalović, Dušan; Jones, Roderic L.; Galea, Karen S.; Etzion, Yael; Kizel, Fadi; Golumbic, Yaela N.; Baram-Tsabari, Ayelet; Yacobi, Tamar; Drahler, Dana; Robinson, Johanna A.; Kocman, David; Horvat, Milena; Svecova, Vlasta; Arpaci, Alexander; Bartonova, Alena

(2017)

TY  - JOUR
AU  - Fishbain, Barak
AU  - Lerner, Uri
AU  - Castell, Nuria
AU  - Cole-Hunter, Tom
AU  - Popoola, Olalekan
AU  - Broday, David M.
AU  - Martinez Iniguez, Tania
AU  - Nieuwenhuijsen, Mark
AU  - Jovašević-Stojanović, Milena
AU  - Topalović, Dušan
AU  - Jones, Roderic L.
AU  - Galea, Karen S.
AU  - Etzion, Yael
AU  - Kizel, Fadi
AU  - Golumbic, Yaela N.
AU  - Baram-Tsabari, Ayelet
AU  - Yacobi, Tamar
AU  - Drahler, Dana
AU  - Robinson, Johanna A.
AU  - Kocman, David
AU  - Horvat, Milena
AU  - Svecova, Vlasta
AU  - Arpaci, Alexander
AU  - Bartonova, Alena
PY  - 2017
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/1343
AB  - Recent developments in sensory and communication technologies have made the development of portable air-quality (AQ) micro-sensing units (MSUs) feasible. These MSUs allow AQ measurements in many new applications, such as ambulatory exposure analyses and citizen science. Typically, the performance of these devices is assessed using the mean error or correlation coefficients with respect to a laboratory equipment. However, these criteria do not represent how such sensors perform outside of laboratory conditions in large-scale field applications, and do not cover all aspects of possible differences in performance between the sensor-based and standardized equipment, or changes in performance over time. This paper presents a comprehensive Sensor Evaluation Toolbox (SET) for evaluating AQ MSUs by a range of criteria, to better assess their performance in varied applications and environments. Within the SET are included four new schemes for evaluating sensors capability to: locate pollution sources; represent the pollution level on a coarse scale; capture the high temporal variability of the observed pollutant and their reliability. Each of the evaluation criteria allows for assessing sensors performance in a different way, together constituting a holistic evaluation of the suitability and usability of the sensors in a wide range of applications. Application of the SET on measurements acquired by 25MSUs deployed in eight cities across Europe showed that the suggested schemes facilitates a comprehensive cross platform analysis that can be used to determine and compare the sensors performance. The SET was implemented in R and the code is available on the first authors website. (C) 2016 Elsevier B.V. All rights reserved.
T2  - Science of the Total Environment
T1  - An evaluation tool kit of air quality micro-sensing units
VL  - 575
SP  - 639
EP  - 648
DO  - 10.1016/j.scitotenv.2016.09.061
ER  - 
@article{
author = "Fishbain, Barak and Lerner, Uri and Castell, Nuria and Cole-Hunter, Tom and Popoola, Olalekan and Broday, David M. and Martinez Iniguez, Tania and Nieuwenhuijsen, Mark and Jovašević-Stojanović, Milena and Topalović, Dušan and Jones, Roderic L. and Galea, Karen S. and Etzion, Yael and Kizel, Fadi and Golumbic, Yaela N. and Baram-Tsabari, Ayelet and Yacobi, Tamar and Drahler, Dana and Robinson, Johanna A. and Kocman, David and Horvat, Milena and Svecova, Vlasta and Arpaci, Alexander and Bartonova, Alena",
year = "2017",
abstract = "Recent developments in sensory and communication technologies have made the development of portable air-quality (AQ) micro-sensing units (MSUs) feasible. These MSUs allow AQ measurements in many new applications, such as ambulatory exposure analyses and citizen science. Typically, the performance of these devices is assessed using the mean error or correlation coefficients with respect to a laboratory equipment. However, these criteria do not represent how such sensors perform outside of laboratory conditions in large-scale field applications, and do not cover all aspects of possible differences in performance between the sensor-based and standardized equipment, or changes in performance over time. This paper presents a comprehensive Sensor Evaluation Toolbox (SET) for evaluating AQ MSUs by a range of criteria, to better assess their performance in varied applications and environments. Within the SET are included four new schemes for evaluating sensors capability to: locate pollution sources; represent the pollution level on a coarse scale; capture the high temporal variability of the observed pollutant and their reliability. Each of the evaluation criteria allows for assessing sensors performance in a different way, together constituting a holistic evaluation of the suitability and usability of the sensors in a wide range of applications. Application of the SET on measurements acquired by 25MSUs deployed in eight cities across Europe showed that the suggested schemes facilitates a comprehensive cross platform analysis that can be used to determine and compare the sensors performance. The SET was implemented in R and the code is available on the first authors website. (C) 2016 Elsevier B.V. All rights reserved.",
journal = "Science of the Total Environment",
title = "An evaluation tool kit of air quality micro-sensing units",
volume = "575",
pages = "639-648",
doi = "10.1016/j.scitotenv.2016.09.061"
}
Fishbain, B., Lerner, U., Castell, N., Cole-Hunter, T., Popoola, O., Broday, D. M., Martinez Iniguez, T., Nieuwenhuijsen, M., Jovašević-Stojanović, M., Topalović, D., Jones, R. L., Galea, K. S., Etzion, Y., Kizel, F., Golumbic, Y. N., Baram-Tsabari, A., Yacobi, T., Drahler, D., Robinson, J. A., Kocman, D., Horvat, M., Svecova, V., Arpaci, A.,& Bartonova, A.. (2017). An evaluation tool kit of air quality micro-sensing units. in Science of the Total Environment, 575, 639-648.
https://doi.org/10.1016/j.scitotenv.2016.09.061
Fishbain B, Lerner U, Castell N, Cole-Hunter T, Popoola O, Broday DM, Martinez Iniguez T, Nieuwenhuijsen M, Jovašević-Stojanović M, Topalović D, Jones RL, Galea KS, Etzion Y, Kizel F, Golumbic YN, Baram-Tsabari A, Yacobi T, Drahler D, Robinson JA, Kocman D, Horvat M, Svecova V, Arpaci A, Bartonova A. An evaluation tool kit of air quality micro-sensing units. in Science of the Total Environment. 2017;575:639-648.
doi:10.1016/j.scitotenv.2016.09.061 .
Fishbain, Barak, Lerner, Uri, Castell, Nuria, Cole-Hunter, Tom, Popoola, Olalekan, Broday, David M., Martinez Iniguez, Tania, Nieuwenhuijsen, Mark, Jovašević-Stojanović, Milena, Topalović, Dušan, Jones, Roderic L., Galea, Karen S., Etzion, Yael, Kizel, Fadi, Golumbic, Yaela N., Baram-Tsabari, Ayelet, Yacobi, Tamar, Drahler, Dana, Robinson, Johanna A., Kocman, David, Horvat, Milena, Svecova, Vlasta, Arpaci, Alexander, Bartonova, Alena, "An evaluation tool kit of air quality micro-sensing units" in Science of the Total Environment, 575 (2017):639-648,
https://doi.org/10.1016/j.scitotenv.2016.09.061 . .
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On the use of small and cheaper sensors and devices for indicative citizen-based monitoring of respirable particulate matter

Jovašević-Stojanović, Milena; Bartonova, Alena; Topalović, Dušan; Lazović, Ivan; Pokrić, Boris; Ristovski, Zoran

(Elsevier, 2015)

TY  - JOUR
AU  - Jovašević-Stojanović, Milena
AU  - Bartonova, Alena
AU  - Topalović, Dušan
AU  - Lazović, Ivan
AU  - Pokrić, Boris
AU  - Ristovski, Zoran
PY  - 2015
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/851
AB  - Respirable particulate matter present in outdoor and indoor environments is a health hazard. The particle concentrations can quickly change, with steep gradients on short temporal and spatial scales, and their chemical composition and physical properties vary considerably. Existing networks of aerosol particle measurements consist of limited number of monitoring stations, and mostly aim at assessment of compliance with air quality legislation regulating mass of particles of varying sizes. These networks can now be supplemented using small portable devices with low-cost sensors for assessment of particle mass that may provide higher temporal and spatial resolution if we understand the capabilities and characteristics of the data they provide. This paper overviews typical currently available devices and their characteristics. In addition it is presented original results of measurement and modelling in the aim of one low-cost PM monitor validation. (C) 2015 Elsevier Ltd. All rights reserved.
PB  - Elsevier
T2  - Environmental Pollution
T1  - On the use of small and cheaper sensors and devices for indicative citizen-based monitoring of respirable particulate matter
VL  - 206
SP  - 696
EP  - 704
DO  - 10.1016/j.envpol.2015.08.035
ER  - 
@article{
author = "Jovašević-Stojanović, Milena and Bartonova, Alena and Topalović, Dušan and Lazović, Ivan and Pokrić, Boris and Ristovski, Zoran",
year = "2015",
abstract = "Respirable particulate matter present in outdoor and indoor environments is a health hazard. The particle concentrations can quickly change, with steep gradients on short temporal and spatial scales, and their chemical composition and physical properties vary considerably. Existing networks of aerosol particle measurements consist of limited number of monitoring stations, and mostly aim at assessment of compliance with air quality legislation regulating mass of particles of varying sizes. These networks can now be supplemented using small portable devices with low-cost sensors for assessment of particle mass that may provide higher temporal and spatial resolution if we understand the capabilities and characteristics of the data they provide. This paper overviews typical currently available devices and their characteristics. In addition it is presented original results of measurement and modelling in the aim of one low-cost PM monitor validation. (C) 2015 Elsevier Ltd. All rights reserved.",
publisher = "Elsevier",
journal = "Environmental Pollution",
title = "On the use of small and cheaper sensors and devices for indicative citizen-based monitoring of respirable particulate matter",
volume = "206",
pages = "696-704",
doi = "10.1016/j.envpol.2015.08.035"
}
Jovašević-Stojanović, M., Bartonova, A., Topalović, D., Lazović, I., Pokrić, B.,& Ristovski, Z.. (2015). On the use of small and cheaper sensors and devices for indicative citizen-based monitoring of respirable particulate matter. in Environmental Pollution
Elsevier., 206, 696-704.
https://doi.org/10.1016/j.envpol.2015.08.035
Jovašević-Stojanović M, Bartonova A, Topalović D, Lazović I, Pokrić B, Ristovski Z. On the use of small and cheaper sensors and devices for indicative citizen-based monitoring of respirable particulate matter. in Environmental Pollution. 2015;206:696-704.
doi:10.1016/j.envpol.2015.08.035 .
Jovašević-Stojanović, Milena, Bartonova, Alena, Topalović, Dušan, Lazović, Ivan, Pokrić, Boris, Ristovski, Zoran, "On the use of small and cheaper sensors and devices for indicative citizen-based monitoring of respirable particulate matter" in Environmental Pollution, 206 (2015):696-704,
https://doi.org/10.1016/j.envpol.2015.08.035 . .
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