• 15-Min Station: A Case Study in North Italy City to Evaluate the Livability of an Area

      Fabio Borghetti; Cristian Giovanni Colombo; Michela Longo; Renato Mazzoncini; Leonardo Cesarini; Luigi Contestabile; Claudio Somaschini (MDPI AG, 2021-09-01)
      The goal of this work is to apply the idea of the city in 15 min to railway stations that can become the starting point of the analysis as they represent the “gateway”, where users start their last mile of travel after getting off the train. Within the research, 11 railway stations located in the Lombardy Region in Italy were identified and analyzed. To perform the analysis, an analytical index was implemented and determined for each station: this index summarizes the main features of the station itself in relation to the territory in which it is located. The adopted approach is comparative: it is not important the absolute value of the index of each station, but the comparison between the different indices. In this way it is possible on the one hand to classify the stations and on the other hand to identify and propose possible interventions to improve the role of a railway station in a territory. The proposed model is expandable and replicable: it is possible to add other useful indicators for the calculation of the index of each station and it is also possible to perform the analysis in different territorial contexts. In fact, it is a decision support tool able to provide indications and information for the planning and programming of the railway system and of the city; among the potential users of the proposed model there are railway station managers and administrations.
    • 15-Minute City: Decomposing the New Urban Planning Eutopia

      Georgia Pozoukidou; Zoi Chatziyiannaki (MDPI AG, 2021-01-01)
      As cities are struggling to cope with the second wave of the global COVID-19 pandemic, the idea of 15-min cities seem to have sparked planners’ imagination and politicians’ willingness for providing us with a new urban planning eutopia. This paper explores the “15-min city” concept as a structural and functional element for redesigning contemporary cities. Methodologically, a study of three case cities that have adopted this new model of city vision, is carried out. The analysis focus on understanding how the idea of 15-min cities fits the legacies of different cities as described by traditional planning principles in the context of three evaluation pillars: inclusion, safety and health. The paper argues that the 15-min city approach is not a radical new idea since it utilizes long established planning principles. Nevertheless, it uses these principles to achieve the bottom-up promotion of wellbeing while it proposes an alternative way to think about optimal resource allocation in a citywide scale. Hence, application of 15-min city implies a shift in the emphasis of planning from the accessibility of neighborhood to urban functions to the proximity of urban functions within neighborhoods, along with large systemic changes in resource allocation patterns and governance schemes citywide.
    • 20 Years of Research on Real Estate Bubbles, Risk and Exuberance: A Bibliometric Analysis

      Shengguo Li; Jiaqi Liu; Jichang Dong; Xuerong Li (MDPI AG, 2021-08-01)
      Since the 2008 global financial crisis, the study of real estate risks, bubbles and exuberance has attracted a lot of attention, which is of great significance to the government, enterprises and individuals. This paper carries out a statistical and bibliometric analysis of 739 studies over the past 20 years in this field, and identifies the theoretical basis, research topics and latest research hotspots in this field. Through the construction of a co-citation network and co-word network, we find that the current studies have commonly employed basic economic theories or econometric methods to detect and quantify real estate bubbles. Explosive bubbles and financialization of real estate are frontier hotspots that have gained much popularity. Based on the comparative study, we further discover that American scholars have paid more attention to topics related to the financial crisis, while Chinese scholars have studied topics more related to real estate market policies. Finally, this paper proposes several important research directions in this field for the future.
    • 200 Years of Feminisation of Professions in Poland—Mechanism of False Windows of Opportunity

      Agnieszka Świgost-Kapocsi (MDPI AG, 2021-07-01)
      This paper presents the problem of the female labour market in Poland and the phenomenon of the feminisation of selected occupations. The main aim was to identify the mechanisms behind the feminisation of occupations in Poland and its consequences by combining considerations of labour market theory with development path theories. This research employed various methods such as the method of analysis of secular trends, as well as a critical reinterpretation of the literature review. Data from the 19th century to 2019 were analysed. The textile industry, education, local public administration, and social care are included in the analysis. The research motivation was to answer the question as to when and under what conditions the selected occupations were feminised. The mechanism of false windows of opportunity was identified, as well as times when the windows of opportunity to enter a given occupation opened and closed for women. Specifically, the research findings described that the female labour market is dependent on the male labour market and thus windows of opportunity offer new employment opportunities but with limited possibilities and under poorer conditions.
    • 2008–2017 Bogota River Water Quality Assessment based on the Water Quality Index

      Daissy Milena Díaz-Casallas; Mario Fernando Castro-Fernández; Elvira Bocos; Carlos Enrique Montenegro-Marin; Rubén González Crespo (MDPI AG, 2019-03-01)
      This article provides a deep analysis of the water quality at the upper basin of the Bogota River (Colombia) between 2008 and 2017. The Water Quality Index has been the indicator employed to determine the ecological status of the river. This index was chosen in order to normalize the analysis, given that it is commonly used by the Institute of Hydrology, Meteorology and Environmental Studies, a government agency of the Ministry of Environment and Sustainable Development of Colombia, to determine the state of surface effluents. The results obtained were organized in a double-entry matrix in order to relate the variables of the sample period and the sampling station. The research revealed an insufficient quality of water, demonstrating that the high stretch of the Bogota River basin has, in general, regular or acceptable water quality, while only five stations showed an acceptable status. Surprisingly, the stations located close to the wastewater treatment plants of the municipalities of Choconta, Suesca, Gachancipa, and Tocancipa, as well as Rio Negro, have a poor water quality, discharging a high load of contaminants into the river. Although great efforts have been made by Colombian authorities to restore the critical state of the majority of their aquatic ecosystems, recent implementation of policies and instruments have not shown significant achievements yet. For this reason, this study aims to present a powerful decision-tool for the monitoring and evaluation of correction measures implemented on this river basin. The data used in this research were provided by the Regional Autonomous Corporation of Cundinamarca.
    • 2050 Scenarios for Long-Haul Tourism in the Evolving Global Climate Change Regime

      Jako Volschenk; Marius Ungerer; Shaun Vorster (MDPI AG, 2012-12-01)
      Tourism and its “midwife”, aviation, are transnational sectors exposed to global uncertainties. This scenario-building exercise considers a specific subset of these uncertainties, namely the impact of the evolving global climate change regime on long-haul tourism (LHT), with a 2050 horizon. The basic problematique is that unconstrained growth in aviation emissions will not be compatible with 2050 climate stabilisation goals, and that the stringency and timing of public policy interventions could have far-reaching impacts — either on the market for future growth of LHT, or the natural ecosystem on which tourism depends. Following an intuitive-logic approach to scenario-building, three meta-level scenarios that can be regarded as “possible” futures for the evolution of LHT are described. Two of these, i.e., the “grim reaper” and the “fallen angel” scenarios, are undesirable. The “green lantern” scenario represents the desired future. Long-haul tourist destinations should heed the early warning signals identified in the scenario narratives, and contribute towards realising the desired future. They should further guard against being passive victims if the feared scenarios materialise, by adapting, repositioning early upon reading the signposts, hedging against risks, and seizing new opportunities.
    • 2052: A Global Forecast for the Next Forty Years. By Jorgen Randers, Chelsea Green Publishing, 2012; 304 pages. Price US$ 24.95 ISBN 978-1-60358-467-8

      Shu-Kun Lin (MDPI AG, 2012-10-01)
      Forty years ago, The Limits to Growth study addressed the grand question of how humans would adapt to the physical limitations of planet Earth. It predicted that during the first half of the 21st century the ongoing growth in the human ecological footprint would stop—either through catastrophic “overshoot and collapse”—or through well-managed “peak and decline.”
    • 2D Versus 3D: The Relevance of the Mode of Presentation for the Economic Valuation of an Alpine Landscape

      Michael Getzner; Barbara Färber; Claudia Yamu (MDPI AG, 2016-06-01)
      In order to value the transformation of landscapes from an economic perspective, survey respondents are usually presented with pictures of various landscapes with the aim to visualize differences in their appearance. The current paper presents a classroom experiment ascertaining differences, and potential advantages and disadvantages, of 2D versus 3D (stereoscopic) presentations of landscape changes. The landscape to be valued was a traditional Alpine pasture in the Austrian Alps as a prominent example of natural and cultural heritage (traditional economy and specific ecology). Two alternative scenarios included, on the one hand, changes in agricultural uses, leading to natural afforestation (reforestation) and decay of existing infrastructure (e.g., hiking trails). On the other hand, significantly extended tourism infrastructure (e.g., new attractions for visitors) was presented. Two groups were presented manipulated pictures (2D/non-stereoscopic), and 3D (stereoscopic) presentations with 3D glasses, respectively. Both groups were then asked for their perception of landscape changes. It turns out that significant differences between the two groups could be detected in terms of the frequency of vacations at Alpine pastures. For instance, respondents in the 3D stereoscopic group stated a significantly higher frequency of trips. However, on the other hand, they did not state a significantly different willingness-to-pay to prevent landscape changes disadvantageous in terms of sustainability. The study results thus suggest that the mode of presentation may affect the valuation of landscape changes depending on the valuation instrument.
    • 2dCNN-BiCuDNNLSTM: Hybrid Deep-Learning-Based Approach for Classification of COVID-19 X-ray Images

      Anika Kanwal; Siva Chandrasekaran (MDPI AG, 2022-06-01)
      The coronavirus (COVID-19) is a major global disaster of humankind, in the 21st century. COVID-19 initiates breathing infection, including pneumonia, common cold, sneezing, and coughing. Initial detection becomes crucial, to classify the virus and limit its spread. COVID-19 infection is similar to other types of pneumonia, and it may result in severe pneumonia, with bundles of illness onsets. This research is focused on identifying people affected by COVID-19 at a very early stage, through chest X-ray images. Chest X-ray classification is a beneficial method in the identification, follow up, and evaluation of treatment efficiency, for people with pneumonia. This research, also, considered chest X-ray classification as a basic method to evaluate the existence of lung irregularities in symptomatic patients, alleged for COVID-19 disease. The aim of this research is to classify COVID-19 samples from normal chest X-ray images and pneumonia-affected chest X-ray images of people, for early identification of the disease. This research will help people in diagnosing individuals for viruses and insisting that people receive proper treatment as well as preventive action, to stop the spread of the virus. To provide accurate classification of disease in patients’ chest X-ray images, this research proposed a novel classification model, named 2dCNN-BiCuDNNLSTM, which combines two-dimensional Convolutional Neural Network (CNN) and a Bidirectional CUDA Deep Neural Network Long Short-Term Memory (BiCuDNNLSTM). Deep learning is known for identifying the patterns in available data that will be helpful in accurate classification of disease. The proposed model (2dCNN and BiCuDNNLSTM layers, with proper hyperparameters) can differentiate normal chest X-rays from viral pneumonia and COVID-19 ones, with high accuracy. A total of 6863 X-ray images (JPEG) (1000 COVID-19 patients, 3863 normal cases, and 2000 pneumonia patients) have been engaged, to examine the achievement of the suggested neural network; 80% of the images dataset for every group is received for proposed model training, 10% is accepted for validation, and 10% is accepted for testing. It is observed that the proposed model acquires the towering classification accuracy of 93%. The proposed network is used for predictive analysis, to prompt people regarding the risk of early detection of COVID-19. X-ray images help to classify people with COVID-19 variants and to indicate the severity of disease in the future. This study demonstrates the effectiveness of the proposed CUDA-enabled hybrid deep learning models, to classify the X-ray image data, with a high accuracy of detecting COVID-19. It reveals that the proposed model can be applicable in numerous virus classifications. The chest X-ray classification is a commonly available and reasonable approach, for diagnosing people with lower respiratory signs or suspected COVID-19. Therefore, it is demonstrated that the proposed model has an efficient and promising accomplishment for classifying COVID-19 through X-ray images. The proposed hybrid model can, efficiently, preserve the comprehensive characteristic facts of the image data, for more exceptional concluding classification results than an individual neural network.
    • 36th Cordoba Guitar Festival: Spectator Analysis Using Structural Equation Modelling (SEM)

      Juan V. Fruet-Cardozo; Jesús C. Pérez-Gálvez; Carol Jara-Alba; Gema Gómez-Casero (MDPI AG, 2019-02-01)
      The Cordoba Guitar Festival is one of the most important cultural events in Spain. This article analyses the musical preferences, satisfaction, attitudinal loyalty, and behavioural loyalty of spectators who attended the 36th festival held in July 2016, as well as the festival’s economic impact on the city. These characteristics of the public give rise to the four hypotheses of this study. To achieve this aim, a structural equation model (SEM) was used. The results −χ<sup>2</sup> = 27.79, with the <i>p</i>-value found to be <i>p</i> = P (χ<sup>2</sup> ≥ 27.79) = 0.224—show the goodness-of-fit of the model and indicate that the observed data do fit the expected dataset. The results therefore allow us to accept the proposed hypotheses concerning the influence of different latent factors, such as musical preferences, loyalty, and satisfaction with the festival. This is the main focus with which the present study has been written. Regarding the economic impact, the Festival raised 1.2 million euros, that is, slightly more than 73,000 euros per day. The amount, although not very high, is important as additional income for the city. The conclusions show the need to consider the preferences of the spectator as an essential tool to enable the continuation and longevity of the Cordoba Guitar Festival—an important cultural destination.
    • 3D Digital Heritage Models as Sustainable Scholarly Resources

      Erik Champion; Hafizur Rahaman (MDPI AG, 2019-04-01)
      If virtual heritage is the application of virtual reality to cultural heritage, then one might assume that virtual heritage (and 3D digital heritage in general) successfully communicates the need to preserve the cultural significance of physical artefacts and intangible heritage. However, digital heritage models are seldom seen outside of conference presentations, one-off museum exhibitions, or digital reconstructions used in films and television programs. To understand why, we surveyed 1483 digital heritage papers published in 14 recent proceedings. Only 264 explicitly mentioned 3D models and related assets; 19 contained links, but none of these links worked. This is clearly not sustainable, neither for scholarly activity nor as a way to engage the public in heritage preservation. To encourage more sustainable research practices, 3D models must be actively promoted as scholarly resources. In this paper, we also recommend ways researchers could better sustain these 3D models and assets both as digital cultural artefacts and as tools to help the public explore the vital but often overlooked relationship between built heritage and the natural world.
    • 3D Interactive Learning Environment as a Tool for Knowledge Transfer and Retention

      Martin Krajčovič; Gabriela Gabajová; Marián Matys; Patrik Grznár; Ľuboslav Dulina; Róbert Kohár (MDPI AG, 2021-07-01)
      The article deals with the design of virtual reality (VR) interactive training as a teaching method and its effect on knowledge transfer and retention of students. The first part presents the methodology of the VR interactive training design. The second part utilizes the created interactive training for a case study to evaluate its effect on the teaching process and to examine the potential of VR interactive training as a sustainable teaching method. The study took place at the Department of Industrial Engineering, Faculty of Mechanical Engineering, University of Žilina. Volunteers were divided into two groups. The first group used VR interactive training as a teaching method, while the second group used the conventional method. Both groups then underwent tests. The main goal was to evaluate the effect of the VR interactive training on the teaching process in comparison to the conventional method while trying to identify the key elements of the VR interactive training design and its influence on knowledge transfer and retention in a sustainable learning environment. At the start of the case study, four hypotheses were formed, questioning the effect of interactive training on knowledge transfer and retention in the long and short term, and its overall influence on the teaching process. Obtained data were then used to evaluate these hypotheses.
    • 3D IoT System for Environmental and Energy Consumption Monitoring System

      Bruno Mataloto; Daniel Calé; Kaiser Carimo; Joao C Ferreira; Ricardo Resende (MDPI AG, 2021-02-01)
      Energy consumption in buildings depends on the local climate, building characteristics, and user behavior. Focusing on user interaction, this research work developed a novel approach to monitoring and interaction with local users by providing in situ context information through graphic descriptions of energy consumption and indoor/outdoor environment parameters: temperature, luminosity, and humidity, which are routinely measured in real-time and stored to identify consumption patterns and other savings actions. To involve local users, collected data are represented in 3D color representation using building 3d models. A simplified color scale depicts environmental comfort (low/comfortable/high temperature/relative humidity) and energy consumption (above/below usual patterns). We found that these indices induced user commitment and increased their engagement and participation in saving actions like turning off lights and better management of air conditioning systems.
    • 3D Numerical Analysis for the Valorization Potential of Spoil Heaps by Shallow Foundations

      Alexandros I. Theocharis; Ioannis E. Zevgolis; Christos Roumpos; Nikolaos C. Koukouzas (MDPI AG, 2022-06-01)
      Coal has been an energy source exploited for several decades, with its extraction being linked to creating wastes. Surface mines’ overburden and interburden materials are typically dumped in spoil heaps, many times without considering their future use. Nowadays, sustainability and circular economy principles demand the efficient valorization of these areas. In that vein, this work investigates alternatives from a geotechnical perspective with shallow foundations for the reclamation of a massive spoil heap. Initially, the installation with a raft foundation of a wind turbine was investigated through a serviceability limit envelope employing 3D finite element analysis. However, the spoil material is too soft to withstand such a massive superstructure, and more advanced foundation techniques are needed. Moreover, the installation of supportive constructions was examined, i.e., buildings with shallow isolated footings using a similar approach and 3D finite element analysis. The soil-footing response is much dependent on the constitutive model, and the potential of small buildings requires further attention. Overall, for the appropriate valorization of the spoil heap, it appears that ground improvement or deep foundations are necessary. This conclusion stands for many similar spoil heaps globally due to the material’s nature.
    • 3D Numerical Analysis of the Natural Ventilation Behavior in a Colombian Greenhouse Established in Warm Climate Conditions

      Edwin Villagran; Rommel Leon; Andrea Rodriguez; Jorge Jaramillo (MDPI AG, 2020-10-01)
      Global food production and availability in hot climate zones are limited by biotic and abiotic factors that affect agricultural production. One of the alternatives for intensifying agriculture and improving food security in these regions is the use of naturally ventilated greenhouses, an alternative that still requires information that allows technical criteria to be established for decision-making. Therefore, the objective of this work was to study the spatial distribution of temperature and relative humidity inside a greenhouse built in the Colombian Caribbean. The methodological approach included the implementation of an experimentally validated 3D numerical simulation model. The main results obtained allowed to determine that the airflows generated inside the greenhouse had average velocities below 0.5 m/s and were mainly driven by the thermal effect of natural ventilation. It was also found that the gradients generated between the interior of the structure and the exterior environment presented values lower than 2.0°C for temperature and −6.3% for relative humidity. These values can be considered low in comparison with other structures evaluated in other regions of the world where the gradients can reach values higher than 10°C and 13% for temperature and relative humidity, respectively.
    • 3D Structure from 2D Dimensional Images Using Structure from Motion Algorithms

      Ismail Elkhrachy (MDPI AG, 2022-04-01)
      Natural disasters and human interference have endangered heritage structures around the world. Therefore, 3D modeling of buildings is important for historical preservation, particularly in low-income and war-affected countries. The majority of 3D structure surveying acquisition approaches, terrestrial laser scanning (TLS), total station measurements, or traditional photogrammetry require either high-cost technologies or professional user supervision. Structure from motion (SfM) approaches address both of these issues by allowing a non-expert user to produce a dense point cloud for real structures by taking a few 2D photographs with a digital camera and processing them with highly automated and freely available data processing tools. The state of the art for the SfM technique is presented in this paper. Agisoft Metashape, VisualSFM, and Regard3D, three well-known types of SfM software, were examined and compared. The 3D point cloud was scaled and transformed into a local coordinates system using total station instruments that were used to obtain some ground control points (GCPs). Ninety-six 2D digital photographs for the historical Emara Palace in Najran, Saudi Arabia, were obtained as data input, and the image matching, bundle adjustment (BA), completeness, and accuracy of three used packages were calculated and compared.
    • 3D Surveying of Underground Built Heritage: Opportunities and Challenges of Mobile Technologies

      Francesco Di Stefano; Alessandro Torresani; Elisa M. Farella; Roberto Pierdicca; Fabio Menna; Fabio Remondino (MDPI AG, 2021-11-01)
      Among the existing Cultural Heritage settings, Underground Built Heritage (UBH) represents a peculiar case. The scarce or lack of knowledge and documentation of these spaces frequently limits their proper management, exploitation, and valorization. When mapping these environments for documentation purposes, the primary need is to achieve a complete, reliable, and adequate representation of the built spaces and their geometry. Terrestrial laser scanners were widely employed for this task, although the procedure is generally time-consuming and often lacks color information. Mobile Mapping Systems (MMSs) are nowadays fascinating and promising technologies for mapping underground structures, speeding up acquisition times. In this paper, mapping experiences (with two commercial tools and an in-house prototype) in UBH settings are presented, testing the different handheld mobile solutions to guarantee an accurate and reliable 3D digitization. Tests were performed in the selected case study of Camerano Caves (Italy), characterized by volumetric complexity, poor lighting conditions, and difficult accessibility. The aim of this research activity is not only to show the differences in the technological instruments used for 3D surveying, but rather to argue over the pros and cons of the systems, providing the community with best practices and rules for 3D data collection with handheld mobile systems. The experiments deliver promising results when compared with TLS data.
    • 3D Underground Property Rights of Transportation Infrastructures: Case Study of Piraeus Metro Station, Greece

      Dionysia-Georgia Perperidou; Konstantinos Sigizis; Agkronilnta Chotza (MDPI AG, 2021-11-01)
      Underground development covers a wide range of underground uses, transportation and infrastructures networks; water and energy storage facilities; municipal spaces, housing, business and manufacturing facilities; and overall exploitation of Urban Underground Space (UUS). According to the Greek legal framework on properties underground, transportation networks, such as the metro, are developed deep enough that no compensation is due to surface parcel owners, which are usually a public entity. The current Greek cadastral system is two-dimensional and there are no records for underground transportation networks. As the need for the exploitation of UUS is arising, especially in densely populated Greek cities, such as Athens, the detailed documentation of transportation networks 3D underground property rights is essential. Herein is presented the technical and legal definition of the 3D underground property rights of the Piraeus Metro Station that is constructed in Piraeus Municipality UUS. Three-dimensional underground models for both Piraeus Station and official cadastral parcels are created so as to identify their 3D spatial intersection. For the identification of their legal and spatial status in 2D, the UUS was subdivided into layers in respect to the station’s vertical infrastructure and then correlated to the current cadastral 2D spatial data. The presented 3D underground property rights of Greece’s major urban underground transportation network facilitates its registration in the current 2D Greek cadastral system and contributes to the better understanding and the identification of legal and technical aspects of UUS rights in Greece.
    • 3D Variables Requirements for Property Valuation Modeling Based on the Integration of BIM and CIM

      Siham El Yamani; Rafika Hajji; Gilles-Antoine Nys; Mohamed Ettarid; Roland Billen (MDPI AG, 2021-03-01)
      The growing rate of urbanization and vertical urban development has aroused the significance of geo-related variables for property units disposed vertically within the same building. Among these, 3D indoor physical and outdoor environmental variables are impacting the property value for each building unit. However, in the literature, the identified 3D variables, by using hedonic pricing models (HPM) for property valuation, are mainly restricted to 3D visualization. Their use in 3D simulation for an accurate evaluation of the property value is still limited. Furthermore, their value is often defined for a specific valuation purpose (e.g., taxation). This paper aims to investigate 3D variables with a significant impact on property value, to combine them with 3D technical requirements and to be integrated in a future valuation model. Moreover, their 3D spatial and non-spatial elements are analyzed to identify which variables can be provided from 3D city models and building scale elements. To accomplish this, the potential of 3D building information modeling (BIM) and city information modeling (CIM) in property valuation is examined. From indoors; BIM/IFC (Industry Foundation Classes) models are the main data sources for structural and living quality variables. While from outdoors, environmental variables and the surrounding building’s information are provided from 3D city models (CityGML).
    • 3D Virtual Itinerary for Education Using Google Earth as a Tool for the Recovery of the Geological Heritage of Natural Areas: Application in the “Las Batuecas Valley” Nature Park (Salamanca, Spain)

      Antonio Miguel Martínez-Graña; José González-Delgado; Silvia Pallarés; José Luis Goy; Jorge Civis Llovera (MDPI AG, 2014-11-01)
      The objective of this study is to develop a methodology that enhances the value and position of the geological heritage of any natural area in the world using a 3D virtual itinerary. Field applications of this geological itinerary enable students to participate actively in teaching and learning theoretical concepts in the earth sciences and engineering. The educational resources, which include a virtual itinerary, a flight simulator, a field notebook with questionnaires, videos, and an augmented reality developed with Google Earth, provide a familiar and effective learning environment that can be implemented by students daily using new technologies (smartphones, tablets, and iPods) and can leverage the power of computer games to achieve the objectives of a specific curriculum. The implementation of geological content in an interactive, educational game has been employed in compulsory levels of secondary education, high school, and college in Batuecas Valley. The geomatic applications are free as they can be accessed from existing computer labs.