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This paper introduces a new routing and touring service both for outdoor and indoor places of touristic and cultural interest designed to be used in the wider area of Attica, Greece. This service is the result of the work performed in OPTORER (OPTORER: OPtimal rouTing and explOration of touRistic and cultural arEas of interest within Attica given personalized adaptive preferences, promoted underlying purpose, and interactive experience), project, and it aspires to offer a range of innovative and thematic routes to several specified points of interest in the selected area of Attica, encouraging the combination of indoor and outdoor routes in a single tour. The aim is to optimize the user experience while promoting specific, user-centric features, with safety and social welfare being a priority for every designed tour, resulting in enhancing the touristic experience in the area. Using a common smartphone device, as well as common wearable devices (i.e., smartwatches), the OPTORER service will provide an end-to-end solution by developing the algorithms and end-user applications, together with an orchestration platform responsible for managing, operating, and executing the service that produces and presents to the end user results derived from solving dynamically complex optimization problems. [ABSTRACT FROM AUTHOR]

The paper investigates the mechanism of seawater intrusion and the performance of free and open-source codes for the simulation of variable density flow problems in coastal aquifers. For this purpose, the research focused on the Marathon Watershed, located in the northeastern tip of Attica, Greece. For the simulation of the groundwater system, MODFLOW, MT3DMS and SEAWAT codes were implemented, while sensitivity analysis and calibration processes were carried out with UCODE. Hydraulic head calibration was performed on the MODFLOW model, and TDS concentration was validated in the SEAWAT model. The calibrated parameters of the MODFLOW model were obtained for the variable density flow simulation with SEAWAT. The MODFLOW and SEAWAT hydraulic head outputs were analyzed and compared to one another. The outcome of this analysis is that SEAWAT produced slightly better results in terms of the hydraulic heads, concluding that parameter transferability can take place between the two models. For the purpose of the seawater intrusion assessment, the use of the SEAWAT code revealed that the aquifer is subjected to passive and passive–active seawater intrusion during wet and dry seasons, respectively. Finally, an irregular shape of a saltwater wedge is developed at a specific area associated with the hydraulic parameters of the aquifer. [ABSTRACT FROM AUTHOR]

Measuring social capital has been a challenging task over the past few decades, and, still, many of its dimensions and manifestations have not been thoroughly or evidently explored. The possible causes may be the ever-changing evolutionary perspectives that take place within the various levels of analysis—micro, meso, and macro—or within the various settings, where some of its core dimensions—bonding, bridging, and linking—are developed, or even among the contexts where its core determinants and features—trust, norms, connections, ties, etc.—are observed. Having in mind the various streams of research and theoretical discourses on social capital formation, this paper aims to surface the identification of the possible evidence on the formation of social capital among social economy organizations, and particularly among social enterprises. In doing so, it aims to explore the relational and cognitive features that drive social enterprises in their interorganizational cooperation with other social enterprises and third-sector organizations. The findings suggest that the central components of social capital, such as the sharing of common values, trust, reciprocity, and trustworthiness, are among those features that were valued most among the participants in the survey during their cooperation and engagement in common activities with other organizations. [ABSTRACT FROM AUTHOR]

In Greece, a new bi-polar high voltage direct current (HVDC) transmission system with a ground return was designed with nominal characteristics of ±500 kV, 1 GW, between Attica in the continental country and the island of Crete, which is an autonomous power system based on thermal diesel units. The interconnection line has a total length of about 380 km. The undersea section is 330 km long. In this paper, the use of the Aegean Sea as an active part of the ground return, based on shoreline pond electrodes, was proposed to avoid EUR 200 Μ of expenses. According to the general guidelines for HVDC electrode design by the International Council on Large Electric Systems (CIGRE) working group B4.61/2017, the electric field and ground potential rise of shoreline electrodes should be studied to analyze safety, electrical interference and corrosion impacts related to the operation of the electrodes. Two kinds of studies are available; one is a simplified approach based on a spherical/pointed electrode centered at the edge of the seashore and seabed, assuming it to be sloping to the horizontal, and the other is a detailed simulated model using a suitable electric field software package. The first approach usually gives more unfavorable results than the second one, especially in the near electric field, while it can not take into account obstacles, i.e., dams, near to electrode position. The second approach demands a detailed description of the wider installation area, which cannot be available during the preliminary study, significant computational time and considerable financial resources for the purchase of a reliable specialized software package. In this research, a two-step modification of the CIGRE simplified model was proposed. The first modification deals with the obstacles in the near electric field, and the second modification deals with the use of a linear current source (instead of a point one), which can give more accurate results. Additionally, the electric field for complex electrode formation is calculated by applying the superposition method, which can be easily achieved using a common software package, i.e., MATLAB. The proposed simplified approaches were applied on shoreline pond electrode locations for the Attica–Crete HVDC interconnection line (between Stachtoroi island in Attica and Korakia beach in Crete), allowing the preliminary study to be conducted swiftly, giving satisfactory results about electric field gradient, ground potential rise and resistance to remote earth of electrodes stations for the near and far electric field. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the association between adherence to the Mediterranean diet and the 20-year incidence of type II diabetes mellitus (T2DM) among adults from the ATTICA study. This study involved a prospective cohort of 3042 men and women recruited at baseline from the Attica region in Greece. Sociodemographic, anthropometric, lifestyle, and clinical characteristics were evaluated at baseline and follow-up examinations; adherence to the Mediterranean diet was assessed through the MedDietScore (range 0–55); four Mediterranean diet trajectories were identified (i.e., increasing, decreasing, and sustained high and sustained low adherence levels). For the present analysis, data from 2000 individuals with complete information were used (age 43 ± 13 years; 49% men). Over the 20-year period, 26.3% (95%CI 24.4%, 28.3%) of participants developed T2DM; men exhibited a 1.5-times higher incidence compared to women (p < 0.001). Individuals consistently close to the Mediterranean diet throughout the studied period had an improved glycemic and lipidemic profile (at baseline and at 10-y follow-up) (all p-values < 0.001) and showed a 21% reduction in their 20-year risk of developing T2DM compared to those who were consistently away (RR = 0.79, 95%CI 0.47, 0.86). A long-term adherence to the Mediterranean diet is protective against the onset of T2DM and, therefore, could be incorporated in public health actions for the prevention of the disease. [ABSTRACT FROM AUTHOR]

Two of the eight main soil degradation processes with which soils worldwide are confronted are soil erosion and landslides. Specifically, landslides are a major threat in particular areas across Europe, often leading to serious impacts on population, property, and infrastructure. Regarding the abovementioned processes, the case study of the fatal Mandra flash flood (November 2017) in the Attica Region (Greece), which caused 24 deaths, and much infrastructure and building damage, is presented with the intention of assessing the relationship between soil erosion and landslide incidents. Investigations were executed from 2018 to 2022, and their outcomes were taken into consideration by the Technical Authority of the Attica Region. Soil erosion lines were delineated in a GIS and were validated using a previously generated regional Web-GIS landslide susceptibility map. The study presents soil erosion types from the Mandra fatal flash flood event and correlates them with already existing landslide susceptibility analyses for the Attica Region. The produced susceptibility map is a cartographic product on a regional scale (1:100,000) generated via a semiquantitative heuristic methodology named the Rock Engineering System (RES). The way in which both soil erodibility and landslide susceptibility maps were generated and validated could be the basis for proposing modeling approaches that can respond to new developments in European landslide policies. [ABSTRACT FROM AUTHOR]

Forest fires are a seasonal phenomenon in Greece, reoccurring annually and causing adverse impacts on both human-made and natural environments. Our case study focuses on the devastating fire that took place in July 2018 in the second-housing area of Mati, East Attica. In this research, we propose a simple and effective approach that combines the deformation trend obtained from the Permanent Scatterer Interferometry (PSI) analysis with the burn severity assessment aiming to identify and classify potential ground-burn hazard zones. To maximize the number of measuring points, we employ a weighted full-graph PSI approach. Additionally, we calculate the burn severity by comparing Sentinel-2 satellite images captured before and after the event. The resulting datasets are reclassified on a scale from 1 to 5, and the proposed equation yields the final product. Numerous high and very high hazard zones have been identified using this methodology. The research findings reveal the proximity between these hazard zones and the stream network. Overall, the proposed method offers valuable insights for the post-fire monitoring and management of urban and peri-urban landscapes in the affected areas. [ABSTRACT FROM AUTHOR]

The aim of this study is to assess the resilience of coastal urban areas and their exposure to sea-level rise and coastal flooding, using the proposed Coastal Resilience Index (CResI). The CResI is an innovative combination of diverse characteristics. It includes 19 parameters and is implemented using GIS techniques. The parameters included in the CResI are classified into six category factors (geomorphology, flooding, wave exposition, land use, socioeconomic, and infrastructure/functional). The Analytic Hierarchy Process is used to assign weights and rank the parameters. The framework is tested in the southwest waterfront of the Athens Metropolitan Area in Greece. The study identified that around 25% of the coastal area could be at risk of coastal flooding in the upcoming years, including areas in both the metropolitan and suburban environments. As a result, the need for adaptation measures cannot be overlooked. [ABSTRACT FROM AUTHOR]

Since 2021, the prefectural authorities of the Attica Region in Greece have been operating a rewarding recycling program for the collection of clean recyclable waste in collaboration with the "Specialist Integrated Association of the Prefecture of Attica" (EDSNA, in Greek) and private contractors, called "THE GREEN CITY". This program mobilizes almost 30 mobile green points (MGPs) daily, which are self-propelled trucks that collect clean recyclable materials from citizens and businesses across the Attica Region. After one year of operation, this program has shown promising results, having more than 100,000 registered citizens and having already collected over 500 tons of clean recyclable municipal solid wastes in more than 60 municipalities of Attica. However, these promising results are accompanied by some significant financial and environmental costs. This study presents two different practical improvement scenarios for THE GREEN CITY recycling program's current situation that ensure (a) the shortening of the annual kilometers and time on the remote routes of all programs, (b) the annual fuel-cost decrease for the MGPs and (c) the annual reduction of their CO2 emissions into the atmosphere. Afterwards, we compare these two scenarios and conclude that the "first improvement scenario with main depot decentralization" is more realistic, feasible and has a bigger total sum of positive impacts than the second one. Therefore, this study strongly suggests the implementation of the "first improvement scenario with main depot decentralization" and opens the road to future improvement scenarios for various waste-management systems or recycling programs. [ABSTRACT FROM AUTHOR]

Image registration is among the most popular and important problems of remote sensing. In this paper we propose a fully unsupervised, deep learning based multistep deformable registration scheme for aligning pairs of satellite imagery. The presented method is based on the expression power of deep fully convolutional networks, regressing directly the spatial gradients of the deformation and employing a 2D transformer layer to efficiently warp one image to the other, in an end-to-end fashion. The displacements are calculated with an iterative way, utilizing different time steps to refine and regress them. Our formulation can be integrated into any kind of fully convolutional architecture, providing at the same time fast inference performances. The developed methodology has been evaluated in two different datasets depicting urban and periurban areas; i.e., the very high-resolution dataset of the East Prefecture of Attica, Greece, as well as the high resolution ISPRS Ikonos dataset. Quantitative and qualitative results demonstrated the high potentials of our method. [ABSTRACT FROM AUTHOR]

This article presents in a comparative way the findings from two surveys conducted on primary (students in Y6) and secondary (students in Y10) students in Attica, Greece, in order to map their views on distance science education, which was emergently implemented due to the COVID-19 outbreak during the school year 2020–2021. The research was conducted in a sample of 378 primary and 197 secondary students. The findings revealed that students were not satisfied with the distance teaching and learning of science, either in primary or in secondary education, except for the increased use of audiovisual material. Technical issues, such as poor network and infrastructure, lack of face-to-face interaction with classmates and teacher, external and internal distractions, lack of sufficient experimental activities, and limited understanding of concepts were common findings in both levels of education. Concerning the differences between the levels, it seems that in primary education more technical problems were reported, while in secondary education more didactic problems were reported. [ABSTRACT FROM AUTHOR]

A lot of autonomous power systems have been designed and operated with different power levels and with special requirements for climatic conditions, availability, operation/maintenance cost, fuel consumption, environmental impacts, etc. In this paper a novel design of an autonomous power system with photovoltaic panels and electrochemical batteries for a shoreline electrode station is analyzed. This station will be constructed on the small island of Stachtoroi for the new high voltage direct current (HVDC) link of Attica–Crete in Greece. The general guidelines of the International Council on Large Electric Systems (CIGRE) and of the International Electrotechnical Committee (IEC) for the power system of lighting and auxiliary loads for these HVDC stations are supplied from the medium voltage or the low voltage distribution network, whereas they do not take into account the criticality of this interconnection, which will practically be the unique power facility of Crete island. The significance of Crete power system interconnection demands an increased reliability level for the power sources, similar to military installations and hospital surgeries. In this research a basic electrical installation design methodology is presented. First, the autonomous photovoltaic power system with the energy storage system (ESS) consisting of electrochemical batteries is preliminary designed according to the relative bibliography. The station power and energy consumption are analytically determined taking into consideration the daily temperature variation annually. Afterwards, a techno-economic optimization process based on a sensitivity analysis is formed modifying the size/power of photovoltaic panels (PVs), the type and the energy capacity of the batteries taking into consideration the operation cycle of PVs—batteries charge and discharge and the battery ageing based on the relationship between battery cycles—the depth of discharge, the daily solar variation per month, the installation cost of PVs and batteries, the respective maintenance cost, etc., while the reliability criteria of expected loss of load power and of load energy are satisfied. Using the proposed methodology the respective results are significantly improved in comparison with the preliminary autonomous power system design or the connection with the distribution power system. [ABSTRACT FROM AUTHOR]

We pose the following research question: "what is the effect of flood protection works on flood risk?" To answer this question, we developed a flood risk assessment method that combines the typical hazard assessment via integrated hydrological and hydrodynamic calculations using HEC-HMS and 1D/2D HEC-RAS, respectively, and an original procedure for vulnerability assessment at the building level, which we applied in the town of Mandra in Attica, Greece. We performed calculations for 15 scenarios—combinations of return periods (T = 20, 50, 100, 150, and 200 y) and rain durations (t = 6, 12, and 18 h)—for the conditions of the year 2017, when there were no flood protection works, and today with these works in place. We identified the regions with high flood risk and concluded that the presence of the works caused a decrease in the inundation areas by 53–89%, along with reductions in the maximum water depths, the maximum flow velocities, and the average flood risk in Koropouli Street—the main street of Mandra, which suffered severe damage during the 2017 flood—by 38–62%, 18–52%, and 27–74%, respectively. The effect of the flood protection works increased with the increases in the return period and rain duration, while for the same return period the effect of the rain duration was more pronounced for the smaller return periods. [ABSTRACT FROM AUTHOR]

In this study, we have compiled new and existing mineralogical and geochemical data on Fe-Mn mineralization from the Aegean region [Attica (Grammatiko, Legrena, and Varnavas), Evia and Milos islands], aiming to provide new insights on the genesis of Fe-Mn mineralization in that region and its potential environmental implications. A common feature of those deposits is the relatively low Cr, Co, V, Ni, Mo, and Cd content, whereas Ba, As, W, Cu, Pb, and Zn show remarkably variable values. The Mn-Fe deposits from Milos exhibit the highest tungsten content, while a positive trend between MnO and W, combined with a negative trend between MnO and Fe2O3 suggests the preference of W to Mn-minerals. The occurrence of bacterio-morphic Fe-Mn-oxides/hydroxides within Mn-Fe mineralizations in the studied region, indicates the important role of micro-organisms into redox reactions. Moreover, the presence of micro-organisms in the Fe-Mn-deposits, reflecting the presence of organic matter confirms a shallow marine environment for their deposition. A salient feature of the Varnavas and Milos Mn-Fe ores is the presence of sodium chloride coated fossilized micro-organisms, suggesting development from a solution containing relatively high Na and Cl concentrations. Furthermore, from an environmental point of view, consideration is given to the bioavailability of elements such as As, Pb, and W, related to the above-mentioned mineralizations. The high bio-accumulation factor for W (Wplant/Wsoil × 100) recorded in the Neogene sedimentary basins of Attica, related to the Grammatiko Fe-Mn mineralization, reflects the high W mobility under alkaline conditions and the potential environmental impact of similar deposits with elevated W content. [ABSTRACT FROM AUTHOR]

We pose the following research question, "what are (i) the minimum required computation grid and (ii) the required form of hydrodynamic equations, i.e., shallow water equations (SWE) or diffusion wave equations (DWE), in 2D modeling to minimize the computational time while maintaining an acceptable level of error in the prediction of water depths and the extent of flood inundated areas?". To answer this question, we apply the HEC-RAS 1D/2D model to simulate a disastrous flash flood in the town of Mandra, in Attica, Greece, in November 2017. HEC-RAS 1D/2D combines 1D modeling in the cross-sections of the two main streams of Mandra with 2D modeling in the rest of the potentially flooded area of the computational domain which has an area equal to 18.36 km2. We perform calculations for 8 scenarios that combined various grid sizes (with approximately 44,000–95,000 control volumes) with the use of the SWE or DWE. We derive the following conclusions: (i) calculated maximum water depths using DWE were equal to 60–65% of the corresponding water depths using SWE, i.e., the DWE significantly underestimated water depths; (ii) calculated total inundation areas using the SWE were approximately 4.9–7.9% larger than the corresponding inundation areas using the DWE; these differences can be considered as acceptable; and (iii) the total computation times using SWE, which ranged from 67 to 127 min, were 60–70% longer than the computation times using DWE. [ABSTRACT FROM AUTHOR]

The environmental effects of wildfires are a hot issue in current research. This study examines the effects of the 2021 wildfires in the Attica region in Greece based on Earth observation and GIS-based techniques for the development of a web app that includes the derived knowledge. The effects of wildfires were estimated with the use of Sentinel-2 satellite imagery concerning burned area extent and burn severity using a NBR-based method. In addition, the erosion risk was modeled on a pre-fire and post-fire basis with the RUSLE. This study highlights the importance of assessing the effects of wildfires with a holistic approach to produce useful knowledge tools in post-fire impact assessment and restoration. [ABSTRACT FROM AUTHOR]

This paper looks at the periodic land use/cover (LUC) changes that occurred in Attica, Greece from 1991 to 2016. During this period, land transformations were mostly related to the artificial LUC categories; therefore, the aim was to map LUC with a high thematic resolution aimed at these specific categories, according to their density and continuity. The classification was implemented using the Random Forests (RF) machine learning algorithm and the presented methodological framework involved a high degree of automation. The results revealed that the majority of the expansion of the built-up areas took place at the expense of agricultural land. Moreover, mapping and quantifying the LUC changes revealed three uneven phases of development, which reflect the socioeconomic circumstances of each period. The discontinuous low-density urban fabric started to increase rapidly around 2003, reaching 7% (from 2.5% in 1991), and this trend continued, reaching 12% in 2016. The continuous as well as the discontinuous dense urban fabric, almost doubled throughout the study period. Agricultural areas were dramatically reduced to almost half of what they were in 1991, while forests, scrubs, and other natural areas remained relatively stable, decreasing only by 3% in 25 years. [ABSTRACT FROM AUTHOR]

To date, due to climate change, heatwaves are more frequent, with greater intensity and duration resulting in deleterious impacts on human health. To be able to manage heatwaves and quantify the impacts on human health, it is crucial to define them and implement policy preventive measures. However, heatwaves are relative to the climate of a location: The same meteorological conditions can constitute a heatwave in one place but not in another. Due to different climatic conditions, social characteristics, and adaptation, heatwaves should be defined on a local scale, which poses difficulties when it comes to comparison of different definitions. The aim of the present study is to define heatwaves, implementing robust statistical analysis for three different indicators (temperature, physiological equivalent temperature (PET), and universal thermal climate index (UTCI)) for three causes of mortality (i.e., cardiological and respiratory mortality and cardiorespiratory mortality) using Attica (Greece) as a case study. Our results define a heatwave for Attica as a period of at least 3 days when the mean temperature is higher than the 97.5th percentile. Afterwards, we encapsulate the harvesting effect by implementing robust statistical analysis, using the Superposed Epoch analysis. Consequently, quantifying heatwaves is crucial so as to create early warning systems and prevent avoidable mortality. [ABSTRACT FROM AUTHOR]

The CyFFORS (Cyprus Flood Forecasting System) project aims at increasing flood risk awareness and promoting preparedness against flooding by developing and validating a pilot flood forecasting system targeted over three river/stream basins in the Larnaca region, Cyprus, and Attica region, Greece. The present study demonstrates the analysis of flood-associated information, based on ground-based and ERA5 model reanalysis data, which is a necessary procedure prior to the development of the hydrometeorological modeling tool, in one of the study areas, namely in the Rafina catchment in Attica, Greece. The analysis focusses on 12 stream flood episodes that occurred in the period 2008–2014. The results show that most events were associated with a typical, for the study area, wet-season cyclonic activity. The detailed investigation of two case studies highlighted important spatiotemporal differences in the generation and development of rainfall, as well as in the flooding magnitude, which were related to specific characteristics of the synoptic-scale forcing, topography and soil moisture preconditioning. Moreover, highly correlated positive relationships were found between the observed maximum stream discharge and the duration and maximum total accumulation of precipitation. A strong positive correlation was also evident between the peak discharge and the flooding impacts, leading to the identification of preliminary discharge thresholds for impact-based warnings, which can be applied to the pilot CyFFORS forecasting system. [ABSTRACT FROM AUTHOR]

The rapid advent in geoinformation technologies, such as Earth Observation (EO) and Geographical Information Systems (GIS), has made it possible to observe and monitor the Earth's environment on variable geographical scales and analyze those changes in both time and space. This study explores the synergistic use of Landsat EO imagery and Support Vector Machines (SVMs) in obtaining Land Use/Land Cover (LULC) mapping and quantifying its spatio-temporal changes for the municipality of Mandra–Idyllia, Attica Region, Greece. The study area is representative of typical Mediterranean landscape in terms of physical structure and coverage of species composition. Landsat TM (Thematic Mapper) images from 1993, 2001 and 2010 were acquired, pre-processed and classified using the SVMs classifier. A total of nine basic classes were established. Eight spectral band ratios were created in order to incorporate them in the initial variables of the image. For validating the classification, in-situ data were collected for each LULC type during several field surveys that were conducted in the area. The overall classification accuracy for 1993, 2001 and 2010 Landsat images was reported as 89.85%, 91.01% and 90.24%, respectively, and with a statistical factor (K) of 0.96, 0.89 and 0.99, respectively. The classification results showed that the total extent of forests within the studied period represents the predominant LULC, despite the intense human presence and its impacts. A marginal change happened in the forest cover from 1993 to 2010, although mixed forest decreased significantly during the studied period. This information is very important for future management of the natural resources in the studied area and for understanding the pressures of the anthropogenic activities on the natural environment. All in all, the present study demonstrated the considerable promise towards the support of geoinformation technologies in sustainable environmental development and prudent resource management. [ABSTRACT FROM AUTHOR]