Danail Brezov

Prof. Danail Brezov

Mathematics, University of Architecture, Civil Engineering and Geodesy, Sofia, Sofia-Grad, Bulgaria
orcid

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 May 2023 in Environmental Research
Verified
Journal Article
Open access
Angel DzhambovAngel Dzhambov
Angel Dzhambov
VDVeronika Simeonova Dimitrova
Veronika Simeonova Dimitrova
NGNevena Germanova
Nevena Germanova
ABAngel Burov
Angel Burov
DBDanail Brezov
Danail Brezov
Reneta DimitrovaReneta Dimitrova
Reneta Dimitrova
Little is still known of how multiple urban exposures interact as health determinants. This study investigated various ways in which greenspace, traffic-related air pollution, and noise could operate together, influencing general health status. In 2022, a cross-sectional population-based survey was conducted in Sofia, Bulgaria. Included were 917 long-term adult residents who completed questionnaires on poor self-rated health (PSRH), total time spent in physical activity (PA), home garden presence, time spent in urban greenspace and nature, and sociodemographics. Residential greenspace was operationalized using the normalized difference vegetation index (NDVI), tree cover density, number of trees, and access to local greenspace and parks. Nitrogen dioxide (NO2) was modeled for the study area. Road traffic, railway, and aircraft day-evening-night sound levels (Lden) were extracted from EU noise maps. Area-level income and urbanicity were considered. Analyses included multivariate ordinal regressions, interactions, and structural equation modeling (SEM). Associations with PSRH were per 0.10 NDVI 300 m: OR = 0.65 (0.42-1.01), home garden: OR = 0.72 (0.49-1.07), per 5 μg/m3 NO2: OR = 1.57 (1.00-2.48), per 5 dB(A) Lden road traffic: OR = 1.06 (0.91-1.23), railway: OR = 1.11 (1.03-1.20), and aircraft: OR = 1.22 (1.11-1.34). Spending >30 min/week in nature related to better health. In multi-exposure models, only associations with aircraft and railway Lden persisted. People with lower education and financial difficulties or living in poorer districts experienced some exposures stronger. In SEM, time spent in nature and PA mediated the effect of greenspace. Greenspace was associated with better general health, with time spent in nature and PA emerging as intermediate pathways. NO2, railway, and aircraft noise were associated with poorer general health. These results could inform decision-makers, urban planners, and civil society organizations facing urban development problems. Mitigation and abatement policies and measures should target socioeconomically disadvantaged citizens.

18 October 2023 in Applied Sciences
Verified
Journal Article
Open access
PDF file
DBDanail Brezov
Danail Brezov
HHHristo Ivanov Hristov
Hristo Ivanov Hristov
DDDimo Dimov
Dimo Dimov
KAKiril Alexiev
Kiril Alexiev
The paper proposes an approach for estimating the rectal temperature of dairy cows based on the non-invasive real-time monitoring of their respiration rates and the temperature-humidity index (THI) of the environment, combined with the analysis of infrared images. We use multimodal machine learning for the joint processing (fusion) of these different types of data. The implementation is performed using a new open source AutoML Python module named AutoGluon. After training and optimizing three different regression models (a neural network and two powerful boosting algorithms), it reduces the variance of the result using level 2 stacking. The evaluation metrics we work with are the mean absolute error, MAE, and the coefficient of determination, R2. For a sample of 295 studied animals, a weighted ensemble provides quite decent results: R2=0.73 and MAE ≈0.1 °C. For another sample of 118 cows, we additionally use the pulse rate as a predictor and we achieve R2=0.65, MAE ≈0.2 °C. The maximal error is almost 1 °C due to outliers, but the median absolute error in both cases is significantly lower: MedAE <0.1 °C, with the standard deviations respectively being 0.118° and 0.137°. These encouraging results give us confidence that tabular and visual data fusion in ML models has great potential for the advancement of non-invasive real-time monitoring and early diagnostics methods.

2 April 2020 in Advances in Applied Clifford Algebras
Verified
Journal Article
Closed access
PDF file
DBDanail Brezov
Danail Brezov

7 April 2023 in Applied Sciences
Verified
Journal Article
Open access
PDF file
DBDanail Brezov
Danail Brezov
ABAngel Burov
Angel Burov
Traffic models have gained much popularity in recent years, in the context of smart cities and urban planning, as well as environmental and health research. With the development of Machine Learning (ML) and Artificial Intelligence (AI) some limitations imposed by the traditional analytical, numerical and statistical methods have been overcome. The present paper shows a case study of traffic modeling with scarce reliable data. The approach we propose resorts on the advantages of ensemble learning using a large number of related features such as road and street categories, population density, functional analysis, space syntax, previous traffic measurements and models, etc. We use advanced regression models such as Random Forest, XGBoost, CatBoost etc., ranked according to the chosen evaluation metrics and stacked in a weighted ensemble for optimal fitting. After a series of consecutive data imputations we estimate the annual average daily traffic distribution in the street and road network of Sofia city and the metropolitan municipality for 2018 and 2022, and the NO2 levels for 2021 with accuracy resp. 78%, 74% and 92%, using AutoGluon and Scikit-Learn.

23 February 2017 in Advances in Applied Clifford Algebras
Verified
Journal Article
Closed access
PDF file
DBDanail Brezov
Danail Brezov