Search Results (32)

Improving the energy efficiency of buildings is a critical pathway in mitigating greenhouse gas emissions and fostering sustainable urban development. This study introduces a simulation-based multi-objective optimization framework designed to enhance both the thermal and economic performance of residential buildings. A representative single-family dwelling located in Patras, Greece, served as a case study to demonstrate the application and scalability of the proposed methodology. The optimization simultaneously minimized two conflicting objectives: the building’s annual thermal energy demand and the cost of construction materials. The computational process was implemented using MATLAB’s Multi-Objective Genetic Algorithm, supported by a modular Excel interface that enables the dynamic customization of design parameters and climatic inputs. A parametric analysis across four optimization scenarios was conducted by systematically varying the key algorithmic hyperparameters—population size, mutation rate, and number of generations—to assess their impact on convergence behavior, Pareto front resolution, and solution diversity. The results confirmed the algorithm’s robustness in producing technically feasible and non-dominated solutions, while also highlighting the sensitivity of optimization outcomes to hyperparameter tuning. The proposed framework is a flexible, reproducible, and computationally tractable approach to supporting early-stage, performance-driven building design under realistic constraints. Full article

Accurate and robust information on land cover changes in urban and coastal areas is essential for effective urban land management, ecosystem monitoring, and urban planning. This paper details the methodology and results of a pixel-level classification and change detection analysis, leveraging 1945 Royal Air Force (RAF) aerial imagery and 2011 Very High-Resolution (VHR) multispectral WorldView-2 satellite imagery from the broader area of Patras, Greece. Our attention is mainly focused on the changes in the coastline from the city of Patras to the northeast direction and the two major rivers, Charadros and Selemnos. The methodology involves preprocessing steps such as registration, denoising, and resolution adjustments to ensure computational feasibility for both coastal and riverbed change detection procedures while maintaining critical spatial features. For change detection at coastal areas over time, the Normalized Difference Water Index (NDWI) was applied to the new imagery to mask out the sea from the coastline and manually archive imagery from 1945. To determine the differences in the coastline between 1945 and 2011, we perform image differencing by subtracting the 1945 image from the 2011 image. This highlights the areas where changes have occurred over time. To conduct riverbed change detection, feature extraction using the Gray-Level Co-occurrence Matrix (GLCM) was applied to capture spatial characteristics. A Support Vector Machine (SVM) classification model was trained to distinguish river pixels from non-river pixels, enabling the identification of changes in riverbeds and achieving 92.6% and 92.5% accuracy for new and old imagery, respectively. Post-classification processing included classification maps to enhance the visualization of the detected changes. This approach highlights the potential of combining historical and modern imagery with supervised machine learning methods to effectively assess coastal erosion and riverbed alterations. Full article

Municipal solid waste management (MSWM) is an advantageous subject for implementing circular economy (CE) strategies. In this context, the waste generation and waste collection steps of MSWM in the third largest Greek city (Patras), in western Greece, were evaluated according to the proposed CE indicators. Public opinion and knowledge on CE in MSWM were also evaluated in a small sample of citizens from the Municipality of Patras (207 individuals) through a questionnaire survey. Results showed that (a) the CE performance indicators objectively assessed circularity in MSWM; (b) Patras fared better than Greece and EU in some indicators [waste generation (kg per capita × year), food waste generation (kg per capita × year)] and worse in others [food waste composting (% w/w), WEEE recycling (kg per capita × year)]; (c) citizens have not adopted CE practices in their waste management; and (d) there is a clear reluctance to change practices in older individuals. Based on these results, some recommendations for improvement were made. These results may aid in delineating existing conditions in MSWM in large eastern Mediterranean cities and contribute to the transition toward a reduction in waste disposal and an increase in material reuse. Full article

All urban and agricultural water distribution networks (WDNs), irrespective of their physical and operational characteristics, encounter substantial leakages which result in significant water losses, environmental degradation through increased carbon emissions, and noteworthy economic burdens. The current work aims to quantify both the environmental impact, estimated in terms of CO₂ emissions, and the economic implications associated with leakages and evaluate the effect of the most widely used leakage reduction strategies. The current approach is applied to the water distribution network of the city of Patras in Western Greece. Full article

LoRa technology is a recent technology belonging to the Low Power and Wide Area Networks (LPWANs), which offers distinct advantages for wireless communications and possesses unique features. Among others, it can be used for localization procedures offering minimal energy consumption and quite long-range transmissions. However, the exact capabilities of LoRa localization performance are yet to be employed thoroughly. This article examines the efficiency of the LoRa technology in localization tasks using Time Difference of Arrival (TDoA) measurements. An extensive and concrete experimental study was conducted in a real-world setup on the University of Patras campus, employing both real-world data and simulations to assess the precision of geodetic coordinate determination. Through our experiments, we implemented advanced localization algorithms, including Social Learning Particle Swarm Optimization (PSO), Least Squares, and Chan techniques. The results are quite interesting and highlight the conditions and parameters that result in accurate LoRa-based localization in real-world scenarios in smart cities. In our context, we were able to achieve state-of-the-art localization results reporting localization errors as low as 300 m in a quite complex 8 km × 6 km real-world environment. Full article

To assess the impact of air pollution on human health in multiple urban areas in Greece, hourly concentrations of common air pollutants (CO, NO₂, O₃, SO₂, PM₁₀, and PM_2.5) from 11 monitoring stations in six major Greek cities (Athens, Thessaloniki, Patra, Volos, Ioannina, and Kozani), were used to implement the U.S. EPA’s Air Quality Index (AQI) during a seven-year period (2016–2022). In Athens, the capital city of Greece, hourly PM₁₀ and PM_2.5 concentrations were also studied in relation to the prevailing wind patterns, while major PM₁₀ episodes exceeding the official daily EU limit (50 μg/m³) were analyzed using the Potential Source Contribution Function (PSCF) in terms of the air mass origin. According to the AQI results, PM₁₀ and PM_2.5 were by far the most hazardous pollutants associated with moderate and unhealthy conditions in all the studied areas. In addition, in Athens, Thessaloniki, and Patra, where the benzene levels were also studied, a potential inhalation cancer risk (>1.0 × 10⁻⁶) was detected. In Athens, Saharan dust intrusions were associated with downgraded air quality, whilst regional transport and the accumulation of local emissions triggered increased PM₁₀ and PM_2.5 levels in traffic sites, especially during cold periods. Our study highlights the need for the development of early warning systems and emission abatement strategies for PM pollution in Greece. Full article

During the Programming Period 2014–2020, dozens of Greek cities drafted Integrated Territorial Investment programmes, based on Integrated Sustainable Urban Development Strategies (ITI SUDs). The Strategies justified the selection of intervention and activity areas using socio-economic analysis. The parameters of that analysis, as specified by the National Coordination Authority, reflected the socio-economic and functional parameters highlighted in the relevant EU regulations. This paper uses a recently published methodology in order to estimate and map deprivation in Greek cities with over 100,000 inhabitants, and compares the results with the activity areas identified in the ITI SUDs of those cities. The paper also makes an estimation of the potential for micro-segregation in deprived areas, in an effort to uncover the links between deprivation, built form and social composition at the micro-scale. The analysis shows that deprivation is comparatively more pronounced in Athens and Thessaloniki, and that the use of a common methodology to measuring deprivation, but with customized measurement scales, could support a more targeted allocation of urban policy resources. On the other hand, micro-segregation seems to be a factor worth exploring only in Athens and Thessaloniki, and not in Patra, Larissa, Volos and Heraklion, where the building stock in areas of deprivation is mostly low-rise. Full article

In an epoch characterized by the swift pace of digitalization and urbanization, the essence of community well-being hinges on the efficacy of urban management. As cities burgeon and transform, the need for astute strategies to navigate the complexities of urban life becomes increasingly paramount. This study employs time series analysis to scrutinize citizen interactions with the coordinate-based problem mapping platform in the Municipality of Patras in Greece. The research explores the temporal dynamics of reported urban issues, with a specific focus on identifying recurring patterns through the lens of seasonality. The analysis, employing the seasonal decomposition technique, dissects time series data to expose trends in reported issues and areas of the city that might be obscured in raw big data. It accentuates a distinct seasonal pattern, with concentrations peaking during the summer months. The study extends its approach to forecasting, providing insights into the anticipated evolution of urban issues over time. Projections for the coming years show a consistent upward trend in both overall city issues and those reported in specific areas, with distinct seasonal variations. This comprehensive exploration of time series analysis and seasonality provides valuable insights for city stakeholders, enabling informed decision-making and predictions regarding future urban challenges. Full article

The SmartAQ (Smart Air Quality) forecasting system produces high-resolution (1 × 1 km²) air quality predictions in an urban area for the next three days using advanced chemical transport modeling. In this study, we evaluated the SmartAQ performance for the urban area of Patras, Greece, for four months (July 2021, September 2021, December 2021, and March 2022), covering all seasons. In this work, we assess the system’s ability to forecast PM_2.5 levels and the major gas-phase pollutants during periods with different meteorological conditions and local emissions, but also in areas of the city with different characteristics (urban, suburban, and background sites). We take advantage of this SmartAQ application to also quantify the main sources of the pollutants at each site. During the summertime, PM_2.5 model performance was excellent (Fbias < 15%, Ferror < 30%) for all sites both in the city center and suburbs. For the city center, the model reproduced well (MB = −0.9 μg m⁻³, ME = 2.5 μg m⁻³) the overall measured PM_2.5 behavior and the high nighttime peaks due to cooking activity, as well as the transported PM pollution in the suburbs. During the fall, the SmartAQ PM_2.5 performance was good (Fbias < 42%, Ferror < 45%) for the city center and the suburban core, while it was average (Fbias < 50%, Ferror < 54%, MB, ME < 3.3 μg m⁻³) for the suburbs because the model overpredicted the long-range transport of pollution. For wintertime, the system reproduced well (MB = −2 μg m⁻³, ME = 6.5 μg m⁻³) the PM_2.5 concentration in the high-biomass-burning emission area with an excellent model performance (Fbias = −4%, Ferror = 33%) and reproduced well (MB < 1.1 μg m⁻³, ME < 3 μg m⁻³) the background PM_2.5 levels. SmartAQ reproduced well the PM_2.5 concentrations in the urban and suburban core during the spring (Fbias < 40%, Ferror < 50%, MB < 8.5 μg m⁻³, ME < 10 μg m⁻³), while it tended to slightly overestimate the regional pollution. The main local source of fine PM during summer and autumn was cooking, but most of the PM was transported to the city. Residential biomass burning was the dominant particle source of pollution during winter and early spring. For gas-phase pollutants, the system reproduced well the daily nitrogen oxides (NO_x) concentrations during the summertime. Predicted NO_x concentrations during the winter were consistent with measurements at night but underestimated the observations during the rest of the day. SmartAQ achieved the US EPA modeling goals for hourly O₃ concentrations indicating good model performance. Full article

Allergic rhinitis is the most common immune disorder worldwide, affecting approximately 10–40% of the general population. It is characterized by an inflammatory response of the nasal mucosa following exposure to non-infectious, inhaled, and airborne allergens that are defined based on the period of exposure to the allergen as annual, seasonal, or episodic. A variety of factors are found to relate to the prevalence of allergic rhinitis, i.e., sex, race, age, seasonality, personal and family-positive atopic history, as well as exposure to environmental and epigenetic factors. In addition to the local inflammation in the nasal mucosa, systemic inflammation is activated in the entire respiratory system, such as rhinoconjunctivitis, asthma, sinusitis, and otitis media with effusion. The aim of this study was to evaluate the trends in the prevalence of allergic rhinitis in the Greek pediatric and adolescent population since 1990. Research was performed in electronic databases (PubMed, ScienceDirect, and Cochrane Library) using appropriate MeSH terms for related studies from 1990 to 2023. We found 12 studies, 11 prospective and 1 cross-sectional, conducted in the cities of Athens, Thessaloniki, Patras and Evros prefecture, with sample sizes varying from 517 to 3076 subjects aged 6–17 years old. The prevalence of allergic rhinitis showed geographic and temporal variability, ranging between 2.1 and 32.5% in children and 25.3 and 30.8% in adolescents, with increasing trends. Factors such as gender (male), age (8–10 years), environmental exposures (moisture, mites, and fungi), positive atopic profile, and family history (asthma and eczema) were related to the manifestation of the disease. The need for systematic research in the Greek child and adolescent population is vital to recognize, prognosis, and control allergic rhinitis manifestations. Full article

The aim of this article is to investigate two external flexible forms of employment—the leasing of workers through Temporary Work Agencies (TWAs) and the contracted workers employed through Business Service Providers (contractors). Undoubtedly, these two forms of employment are complex and often give rise to confusion. First, this article reviews the characteristics of these types of workers and the operation of these businesses. Second, it presents the results of a mixed method of empirical research (quantitative and qualitative) regarding contracted workers. Our sample was 365 contracted workers from the cities of Athens, Thessaloniki and Patras, Greece. In particular, quantitative research is conducted using a methodology called RDS (Respondent Driven Sampling) that is innovative in the field of labour economics and labour relations. Some significant findings of our qualitative research are used to improve, extend, and interpret the quantitative results. Our research proves that contracted workers, who are employed at the premises of the banks, are leased workers, and the contracting undertakings usually operate unlawfully as TWAs. Our research proves that Banks in Greece are using “pseudo-contracting” to circumvent the European Directive 2008/104/EC and the Greek Laws 4052/2012 and 4254/2014, both of which provide institutional protection to workers leased through TWAs. In more detail, the relevant European Directive and the Greek Law 4052/2012 provide salary equality and equal labour rights for the leased workers in Greece and the EU, when they share the same qualifications as the permanent employees of the user undertakings. The employers’ aim in adopting this policy is mainly to pay lower salaries to contracted workers, who in practice have the characteristics of leased workers. Full article

Urban traffic congestion and vehicle/passenger port recurring delays are major obstacles of coastal urban area sustainability. Most research in coastal urban road management has focused on congestion detection without the effective integration of the dynamic interactions with port queueing systems. For securing coastal city environmental, social and economic efficiency, this paper develops and tests a dynamic urban coastal traffic and port management system. The integrated system controls traffic and port gates’ operations based on ITS/C-ITS methodologies. The system integrates dynamic models for congestion detection, using ANN and a parameterized model, on a coastal urban road network that leads to a city port and identifies optimal solutions for road traffic and port queuing gate control. The system communicates with users via connected vehicles and VMS. The system was tested in a coastal urban road leading to Patras Southern Port, Greece, and at port control gates. Field and simulation data were used to assess system performance and social–environmental impacts. The results reveal that the system’s application offers benefits to the individual driver moving towards the Port to board a ship (gaining at least 7 min and consuming 0.306 L less fuel) as well as to society (39.72% increase in traffic safety) and environment (1,445,132 g CO₂ emission reduction). Full article

Cycling’s integration into the intricate facets of urban design, together with walking and public transportation, offers an effective solution to the mobility issues plaguing urban spaces, and is critical to the sustainability of modern cities. In this context, in this research urban cyclists’ needs and preferences are analyzed through questionnaires, and bicycle accessibility to urban areas is assessed using multicriteria analysis. The public’s familiarity with the integration of novel mobility solutions (e.g., e-bicycles) that support accessibility and inclusiveness is tested and analyzed by recording cyclists trajectories on bicycle routes. The European hub of Patras was selected as the case study for a pilot scheme in this analysis. Similar to many medium-sized European cities, several mobility obstacles, including urban topography, hinder bicycle accessibility in the city, especially between the Modern and Old City areas. The research findings indicate that, addressing these obstacles, electric bicycles can substantially increase bicycle accessibility in the city center. The public usage of electric bicycles is encouraged in the pilot study, and the results indicate that it can increase accessibility to urban areas while reducing restrictions related to age, physical condition, and disabilities. Providing citizens access to e-bicycles can increase the number of daily bicycle users, leading to positive impact in urban cohesion, resilience, and sustainability. Full article

The Patras Gulf Pockmark field is located in shallow waters offshore Patras City (Greece) and is considered one of the most spectacular and best-documented fluid seepage activities in the Ionian Sea. The field has been under investigation since 1996, though surveying was partially sparse and fragmentary. This paper provides a complete mapping of the field and generates new knowledge regarding the fluid escape structures, the fluid pathways, their origin and the link with seismic activity. For this, data sets were acquired utilising high-resolution marine remote sensing techniques, including multibeam echosounders, side-scan sonars, sub-bottom profilers and remotely operated vehicles, and laboratory techniques focusing on the chemical composition of the escaping fluids. The examined morphometric parameters and spatial distribution patterns of the pockmarks are directly linked to tectonic structures. Acoustic anomalies related to the presence of gas in sediments and in the water column document the activity of the field at present and in the past. Methane is the main component of the fluids and is of microbial origin. Regional and local tectonism, together with the Holocene sedimentary deposits, appear to be the main contributors to the growth of the field. The field preserves evidence that earthquake activity prompts the activation of the field. Full article

Particulate matter (PM) pollution is a major global concern due to its negative impact on human health. To effectively address this issue, it is crucial to have a reliable and efficient forecasting system. In this study, we propose a framework for predicting particulate matter concentrations by utilizing publicly available data from low-cost sensors and deep learning. We model the temporal variability through a novel Long Short-Term Memory Neural Network that offers a level of interpretability. The spatial dependence of particulate matter pollution in urban areas is modeled by incorporating characteristics of the urban agglomeration, namely, mean population density and mean floor area ratio. Our approach is general and scalable, as it can be applied to any type of sensor. Moreover, our framework allows for portable sensors, either mounted on vehicles or used by people. We demonstrate its effectiveness through a case study in Greece, where dense urban environments combined with low cost sensor networks is a peculiarity. Specifically, we consider Patras, a Greek port city, where the net PM pollution comes from a variety of sources, including traffic, port activity and domestic heating. Our model achieves a forecasting accuracy comparable to the resolution of the sensors and provides meaningful insights into the results. Full article