Christos Chalkias

Prof. Christos Chalkias

Harokopio University of Athens, Athens, Attikí, Greece

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

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

Representative Publications

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1 April 2006 in Journal of Environmental Management
Verified
Journal Article
Closed access
Christos ChalkiasChristos Chalkias
Christos Chalkias
MPM. Petrakis
M. Petrakis
Basil E. PsiloglouBasil E. Psiloglou
Basil E. Psiloglou
MLM. Lianou
M. Lianou

20 August 2014 in Geosciences
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Journal Article
Open access
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Christos ChalkiasChristos Chalkias
Christos Chalkias
MFMaria Ferentinou
Maria Ferentinou
Christos PolykretisChristos Polykretis
Christos Polykretis
: In this paper, bivariate statistical analysis modeling was applied and validated to derive a landslide susceptibility map of Peloponnese (Greece) at a regional scale. For this purpose, landslide-conditioning factors such as elevation, slope, aspect, lithology, land cover, mean annual precipitation (MAP) and peak ground acceleration (PGA), and a landslide inventory were analyzed within a GIS environment. A landslide dataset was realized using two main landslide inventories. The landslide statistical index method (LSI) produced a susceptibility map of the study area and the probability level of landslide occurrence was classified in five categories according to the best classification method from three different methods tested. Model performance was checked by an independent validation set of landslide events. The accuracy of the final result was evaluated by receiver operating characteristics (ROC) analysis. The prediction ability was found to be 75.2% indicating an acceptable susceptibility map obtained from the GIS-based bivariate statistical model.

Verified
Journal Article
Open access
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Andreas TsatsarisAndreas Tsatsaris
Andreas Tsatsaris
Kleomenis KalogeropoulosKleomenis Kalogeropoulos
Kleomenis Kalogeropoulos
NSNikolaos Stathopoulos
Nikolaos Stathopoulos
PLPanagiota Louka
Panagiota Louka
KTKonstantinos Tsanakas
Konstantinos Tsanakas
Christos ChalkiasChristos Chalkias
Christos Chalkias
Human activities and climate change constitute the contemporary catalyst for natural processes and their impacts, i.e., geo-environmental hazards. Globally, natural catastrophic phenomena and hazards, such as drought, soil erosion, quantitative and qualitative degradation of groundwater, frost, flooding, sea level rise, etc., are intensified by anthropogenic factors. Thus, they present rapid increase in intensity, frequency of occurrence, spatial density, and significant spread of the areas of occurrence. The impact of these phenomena is devastating to human life and to global economies, private holdings, infrastructure, etc., while in a wider context it has a very negative effect on the social, environmental, and economic status of the affected region. Geospatial technologies including Geographic Information Systems, Remote Sensing—Earth Observation as well as related spatial data analysis tools, models, databases, contribute nowadays significantly in predicting, preventing, researching, addressing, rehabilitating, and managing these phenomena and their effects. This review attempts to mark the most devastating geo-hazards from the view of environmental monitoring, covering the state of the art in the use of geospatial technologies in that respect. It also defines the main challenge of this new era which is nothing more than the fictitious exploitation of the information produced by the environmental monitoring so that the necessary policies are taken in the direction of a sustainable future. The review highlights the potential and increasing added value of geographic information as a means to support environmental monitoring in the face of climate change. The growth in geographic information seems to be rapidly accelerated due to the technological and scientific developments that will continue with exponential progress in the years to come. Nonetheless, as it is also highlighted in this review continuous monitoring of the environment is subject to an interdisciplinary approach and contains an amount of actions that cover both the development of natural phenomena and their catastrophic effects mostly due to climate change.

3 March 2023 in Applied Sciences
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Journal Article
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CTChrysovalantis-Antonios D. Tsiakos
Chrysovalantis-Antonios D. Tsiakos
Christos ChalkiasChristos Chalkias
Christos Chalkias
Climate change and its effects (i.e., sea level rise, extreme weather events) as well as anthropogenic activities, determine pressures to the coastal environments and contribute to shoreline retreat and coastal erosion phenomena. Coastal zones are dynamic and complex environments consisting of heterogeneous and different geomorphological features, while exhibiting different scales and spectral responses. Thus, the monitoring of changes in the coastal land classes and the extraction of coastlines/shorelines can be a challenging task. Earth Observation data and the application of spatiotemporal analysis methods can facilitate shoreline change analysis and detection. Apart from remote sensing methods, the advent of machine learning-based techniques presents an emerging trend, being capable of supporting the monitoring and modeling of coastal ecosystems at large scales. In this context, this study aims to provide a review of the relevant literature falling within the period of 2015–2022, where different machine learning approaches were applied for cases of coast-line/shoreline extraction and change analysis, and/or coastal dynamic monitoring. Particular emphasis is given on the analysis of the selected studies, including details about their performances, as well as their advantages and weaknesses, and information about the different environmental data employed.


3 February 2014 in Journal of Diabetes & Metabolic Disorders
Verified
Journal Article
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STStefanos Tyrovolas
Stefanos Tyrovolas
Christos ChalkiasChristos Chalkias
Christos Chalkias
MMMarianthi Morena
Marianthi Morena
Kleomenis KalogeropoulosKleomenis Kalogeropoulos
Kleomenis Kalogeropoulos
NTNikos Tsakountakis
Nikos Tsakountakis
DPDemosthenes Panagiotakos
Demosthenes Panagiotakos
Climate variation has long been studied in relation to human health. The aim of the present work was to evaluate the relationship between environmental humidity, and air temperature with the prevalence of diabetes, among elderly islanders. During 2005–2011, 1959 elderly (aged 65 to 100 years) individuals from 13 Mediterranean islands were enrolled. Socio-demographic, clinical and lifestyle factors were assessed using standard procedures. Diabetes was defined as fasting blood glucose levels > 125 mg/dl. Relative environmental humidity was measured as a percentage of air moisture and mean daily temperature in degrees Celsius. For the present analysis 713 men (74 ± 7 years) and 596 women (73 ± 7 years) with complete data were studied; 27% of both men and women had diabetes. The prevalence of diabetes was 42% in the elders living in high relative humidity areas (i.e., >70%) as compared with 24% among those living at low relative humidity residential areas (p < 0.001). After adjusting for age, sex and mean temperature, an increase in the area’s relative humidity by 1 degree, increased the likelihood of having diabetes by 12% (OR = 1.12, 95% CI 1.05 to 1.20). No significant association was observed between mean temperature and diabetes (OR = 0.97, 95% CI 0.74, 1.26). A considerable proportion of elderly, especially those living in high relative humidity areas, had diabetes. Further research is needed to confirm this observation and to understand the underlying mechanisms.