2025 Volume 13 Issue 1 Pages 230-256
Sustainable urban development is a growing area of research, with cities worldwide facing various economic, social, and environmental challenges due to rapid urbanization. This study provides a comprehensive review of sustainable urban development literature through content analysis and application of artificial intelligence techniques. The objectives of this research are: 1) To conduct a systematic literature review of research published between 2012-2022, analyzing dimensions studied and trends over time and across continents/countries. 2) To utilize BERT to automatically classify articles into sustainable urban development dimensions based on titles and abstracts. A systematic literature review was conducted by collecting data from articles indexed on Google Scholar with the keyword 'sustainable urban development.' The initial search yielded 790 articles, which were screened using predefined inclusion and exclusion criteria, resulting in a final selection of 705 articles. Subsequently, a panel of 30 experts was engaged to refine and prioritize dimensions for analysis. Using the Delphi method, a consensus was reached to identify five key dimensions: environmental-ecological, economic, socio-cultural, political (managerial-institutional), and demographic. Statistical analysis was performed on trends by continent, country, and year. The results show Asia had the largest share of articles, followed by Europe, Africa, North America, South America, and Oceania. Iran, Sweden, Egypt, the US, Brazil, and Australia ranked highest for their continents, respectively. The environmental-ecological dimension received the most attention. Statistical analysis of research trends over ten years across six continents and 92 countries provided novel insights. The BERT model was also able to automatically classify articles with 59% accuracy based on titles, abstracts, and topics, demonstrating its potential to organize vast literature efficiently. In conclusion, this research presents the most comprehensive review of sustainable urban development research to date and introduces an AI technique that can facilitate comparative studies and identification of best practices. The classification of literature into dimensions also provides a framework for structured analysis of trends.
Cities significantly affect the extent of the continental biosphere, various aspects of human life, and the formation of urban spaces, along with the history of a nation over time. Understanding historical and regional variation in urban trajectories can provide long-term perspectives on contemporary urban challenges, enriching insights into how cities shape international development and environmental policy agreements while fueling engines of economic growth (Ali-Toudert, Ji et al., 2020; Ruan and Wu, 2015). 75% of the world's energy comes from cities, and 80% of its carbon dioxide emissions come from cities. This shows how much pressure cities put on the world's regions (Moroke, Schoeman et al., 2019). Urban life is constantly unstable, leading to potentially adverse ecological effects, economic crises, and social tensions and, thus, necessitating more fundamental changes that are inherently sustainable (Neshani Fam and Haghgoshaei, 2015). Therefore, the United Nations General Assembly approved 17 sustainable development goals in 2015 to promote the concept of sustainability and address economic, social, and environmental issues (Halkos and Gkampoura, 2021), This is particularly applicable aimed at 11, which seeks to ensure that cities and human settlements are inclusive, safe, resilient, and sustainable (Smets and van Lindert, 2016).
Planning based on sustainable urban development is an essential sustainability solution, which is effective both at the urban and continental scales and should be under urban monitoring systems and organization, including sustainable social organization and sustainable urban management (Barakpou and Keivani, 2016; Yang, Xu et al., 2017). In order to achieve the most significant influence on global sustainable development, it is imperative to effectively carry out urban sustainability initiatives and foster sustainable urban development. This is due to the projected increase of 2.5 billion individuals in the urban population by 2050, which will necessitate additional resources and pose heightened economic, environmental, and social challenges (Liang, Zhang et al., 2016). Sustainable urban development should focus on the realization of social justice, provision of basic services, environmental protection, reduction of urban costs, and coordinated citizen development in a specific space (Cobbinah and Darkwah, 2017; El Sakka, 2016). Sustainable urban development can ensure a desirable urban future while improving the quality of life in environmental, cultural, political, institutional, social, and economic dimensions (Zhu, Yu et al., 2018) and establishing interaction and integration with each subsystem of these dimensions to reach a relative level of urban population welfare in the long run (Yigitcanlar and Teriman, 2015). Sustainable urban development is crucial for improving urban infrastructure, local services, and the overall well-being of both current and future generations. The process entails the incorporation of economic, environmental, and social elements in order to enhance living conditions, enhance cities' attractiveness, and increase their competitiveness. Sustainable urban development aims to reduce negative impacts on natural resources and improve the quality of life for communities. This concept requires alignment in planning, design, and implementation to achieve its objectives and contribute to the overall sustainability of urban areas (Medved, Kim et al., 2020; Wikantiyoso and Suhartono, 2018; Wikantiyoso, Tutuko et al., 2020).
Sustainable urban development has been at the center of urban planning in developed countries, particularly in the last three decades, but it goes beyond the scope of urban planning in developing countries (Tran, 2016). Urban planning should be at the center of development in the concept of sustainability, which is a prominent issue in international discussions (Ltzkendorf and Balouktsi, 2017). In other words, many cities worldwide faced sustainable development challenges due to rapid urban transformation and growth, which could be addressed through more reliance on the characteristics and opportunities of urban life (Shoja and Heidari, 2015). It is crucial to address the demands of the present urban population while also considering the needs of future generations. This highlights the significance of conducting further study on sustainable urban development, which is a complex and multidimensional system consisting of both external and internal subsystems (Alibekova, Panzabekova et al., 2018). This goal will not be achieved without sufficient knowledge of the national and global importance of sustainability indicators (Heydari and Bakhtar, 2018).
While research interest and published studies on sustainable cities have grown in recent decades, the breadth of this research literature has made systematically mapping and synthesizing this field a significant challenge. Most prior reviews have been limited in scope, focusing on specific geographical areas, academic disciplines, or sustainability dimensions. Comprehensively analyzing patterns and trends across this diffuse literature is crucial to inform evidence-based urban planning and policy worldwide. Therefore, the current research effort will help fill this need through a large-scale content analysis of recent sustainable urban development research. Gaining a broad understanding of sustainable urban development research's current state and direction will help scholars, planners, and policymakers prioritize the most urgent issues and promising solutions to improve urban sustainability outcomes globally. More informed and strategic research directions can guide cities toward more effective, equitable, and environmentally sound planning processes.
This study has two primary objectives. The first is to conduct a systematic content analysis of recent research on sustainable urban development published between 2012-2022. Through this analysis, each study is categorized based on its primary focus within one of the core dimensions of sustainable urban development, and trends in the prevalence of these topics are analyzed globally and across continents.
The second key objective is to demonstrate the potential of using natural language processing methods like BERT to automate the categorization of research articles based on their content. A BERT model is trained on the dataset compiled from the manual content analysis. Showing the feasibility of an automated classification approach highlights promising techniques to make large-scale meta-research more efficient and reproducible.
Overall, this dual focus on substantive trends in the sustainable urban development research literature and the introduction of computational text analysis methods aims to synthesize the current research knowledge and provide an example application of leading AI tools in this increasingly important domain. The content analysis provides a valuable knowledge base, while the text classification model explores how machine learning can accelerate and supplement such efforts.
Literature review and bibliographic analysis of sustainability and sustainable development in urban context have focused on five dimensions.
Urban transportation and sustainable developmentBased on 2543 articles published in the WOS database during 2000-2017, research has mainly examined the effects of transportation infrastructure on sustainable development in the United States, England, and China, particularly investigating the economic, social, and environmental impacts of transportation infrastructure from a larger perspective (Wang, L., Xue et al., 2018). The analysis of 729 articles on services found in the WOS database showed that carpooling services were proposed as a potentially effective solution for sustainable urban transportation and private car ownership reduction in the context of sustainable cities (Esfandabadi, Diana et al., 2022). Besides, according to 87 articles on last-mile business sustainability management services during 2014-2021, logistics sustainability and the impact of logistics and technologies used in it can affect social integration, consumers, and government officials (Lauenstein and Schank, 2022). A theoretical study framework was provided for future sustainable urban freight transport, focusing on two perspectives: the urban development process and the application of urban distribution innovations, using a combination of future studies during 2003-2018 with the perspective of transfer theory and highlighting the contribution of urban freight transportation to promoting livable and sustainable cities from management, policy, stakeholder, and risk assessment dimensions (He and Haasis, 2020).
Smart cities and sustainable developmentTwenty-five articles extracted from Scopus, Science Direct, and Emerald Insight databases compared and contrasted the concepts of smart cities and sustainable development with the aim of sustainable development of smart cities (Trindade, Hinnig et al., 2017). A 35-year analysis of the urban sustainability concepts in the SCI and SSCI databases highlighted the sustainable city as an ideal urban form, representing the most prominent and significant concept of sustainable and smart cities. The analysis also indicated that each urban concept had a distinct development timeline and regional characteristics (Fu and Zhang, 2017). A review of 87 articles using VOSviewer® showed that smart cities were one of the four perspectives of sustainable environmental planning for spatial arrangement in time scales and adaptive cycles, emphasizing that the ecosystem service provider's context quality is a determining factor in sustainable urban development (Ramirez Lopez and Grijalba Castro, 2020).
Urban planning-assessment and sustainable developmentAn analysis of 124 publications in WOS and Scopus databases during 2015-2018 showed that environmental impacts still attract much attention in the most common urban sustainability assessment systems, which focus on the socio-economic dimensions (Pedro, Reis et al., 2019). A total of 117 papers were found in the two stated databases that examined the creation of neighbourhood sustainability assessment tools in response to the challenges posed by growing urbanisation, environmental issues, and the need for sustainable cities. However, it is crucial to consistently address sustainability concerns and include sustainable urban planning and design into the existing framework of neighbourhood sustainability evaluation methods (Dawodu, Cheshmehzangi et al., 2022). In addition, based on the Scopus database, over 30 papers published between 2011 and 2020 have found that sustainable urban planning in Western countries was influenced by the socio-cultural and political aspects of the host countries in emerging economies (Permana, Harsanto et al., 2020). CiteSpace was used in the WOS and CNKI databases to address the issue of promoting sustainable development for global spatial planning as a critical action for countries during 2006-2021, indicating an increase in China after 2018. Globally, the United States and Italy had the highest number of research results and collaborations with other countries on this topic, respectively, confirming the higher contribution of developed countries to sustainable urban development research. However, it is noteworthy that the spatial planning and terminologies of each country should be assessed according to its national conditions and different periods (Zhang, J., Wang et al., 2022).
Urbanization-urban renovation and sustainable developmentCiteSpace was used with the threshold time set from 1990 to 2020 to examine 3640 articles published in WOS, CNKI, and Scopus databases on sustainable urban development. Studies on sustainable urbanization have investigated the conditions and potential trends in the research development and the effects of sustainable urbanization in different countries, especially the US, China, and Germany, which have the most significant research initiatives (Zhang, D., Xu et al., 2020). A review of 81 articles on urban renovation and sustainable development published in the SCI database during 1990-2012 highlighted the importance of research conducted based on planning and social subsystems. Solutions and strategies were also presented, particularly to the community of academics and researchers, to evaluate the past, present, and future status of urban renovation and achieve sustainable urban renovation (Zheng, Shen et al., 2014).
Sustainable development and other urban areasThe analysis of 995 articles showed associations between sustainability and multidisciplinary fields, including engineering, economic, social, and environmental sciences. Therefore, it is important to analyse the prevailing elements of sustainable urban infrastructure and their development (Ferrer and Thom, 2018). An examination of the articles sourced from the CNKI and WOS databases unveiled the concept of urban carrying capacity (UCC) within the context of sustainable urban development in China. There was a greater emphasis on researching the environmental carrying capacity compared to social and economic categories, as evidenced (Meng, Du et al., 2020). A total of 134 papers focusing on the sustainability of big projects between 1998 and 2018 were chosen from the Scopus and WOS Core Collection databases. Countries such as China, Korea, Great Britain, Brazil, India, and Australia had the highest levels of participation in large projects, surpassing other countries. This trend reflects the shift in research focus from environmental concerns to social and economic issues (Wang, G., Wu et al., 2020). The scope definition and thematic investigation in urban resilience literature were introduced as emerging fields through a review of 1014 publications during 1998-2020 in the WOS database and CiteSpace software. It was shown that most urban resilience researchers accepted urban resilience as an important sustainable development goal (Bautista-Puig, Benayas et al., 2022).
The application of AI in text classification Transformer networks in text classificationResearch in the field of NLP has increasingly used the Transformer Model in recent years. Transformer is a Deep Learning model that uses Attention Mechanism, in which one word affects others in the sentence according to their similarity. A transformer model receives a sentence as an input and delivers the output according to the desired task. This model consists of a group of related Encoders and Decoders with an equal number. The structure of all encoders is similar, and all decoders also have a similar structure (Vaswani, Shazeer et al., 2017).
Transformer models were primarily used for the text translation task. Google engineers trained a large model with a lot of data and made it available to everyone to enable their application in other tasks in the field of NLP, such as text classification. By using these pre-trained models, NLP tasks using the acquired data sets can be completed with a limited processing resource. A collection of Transformer Model encoders that have been trained and released in two sizes—12 and 24-layer encoders known as BERT BASE and BERT LARGE models, respectively—make up the Bidirectional Encoder Representations from Transformer (BERT) model. There are two applications for the BERT model in network training: feature extraction and fine-tuning (Devlin, Chang et al., 2018).
AI applications in the classification of sustainable development textsThe classification of sustainable development texts was mainly used in the United Nations programs and research works. Transformer and SVM networks allocated the greatest share to themselves in these studies. A study showed that the best output model could be obtained using SVM and LP to classify texts based on 17 sustainable development goals of 2030 (Morales-Hernndez, Becerra-Alonso et al., 2022; Morales-Hernndez, Jagey et al., 2022). Another study introduced a deep learning-based tool called SDG-Meter, which worked based on transformer networks and could automatically display the sustainable development goals related to the input text in the output (Guisiano, J. E., Chiky et al., 2022).
Researchers used deep learning in another study to present a method with multilabel text classification that had automatic labeling. This method effectively combined the similarities of documents based on general deep learning with the F-IDF document to classify the most relevant sustainable development goals of the United Nations resolutions (Sovrano, Palmirani et al., 2020). Through an internet search, the researchers could prepare a dataset of labeled and unlabeled texts from related documents of Sustainable Development Goals (SDGs), after which the relevant texts were classified using the ULMFiT method and the BERT model (Rodrguez Medina, 2019). Another article utilised a pre-trained customised BERT model to acquire a multi-label text classifier model capable of recognising and interpreting input texts in relation to SDGs (Matsui, Suzuki et al., 2022). Researchers have also used RoBERTa-based classification models to automatically process a set of large documents related to sustainable development goals, leading to promising results (Angin, Tademir et al., 2022). In another study, researchers presented a multi-label text classification algorithm using BERT in the OnePlanet open participation network for sustainable development, which accelerated the processing of texts related to SDGs (Guisiano, J. and Chiky, 2021).
New innovationsIt conducted the largest and most comprehensive review of sustainable urban development literature to date by analyzing over 700 articles from 2012-2022.
It introduces AI/machine learning technique of BERT model to facilitate automated classification of vast literature according to sustainability dimensions and topics at a larger scale compared to manual analysis.
The BERT model classification could help identify best practices, solutions transferable between places and facilitate comparative studies in a holistic manner.
It demonstrates how advanced computational techniques like BERT can efficiently organize existing research to fill critical knowledge gaps and support more informed policymaking for sustainable urban development.
The extensive statistical analysis of research trends over a 10 year period, across 6 continents and 92 countries provides novel insights not explored before at this coverage and depth.
The classification of literature into 5 key dimensions provides a framework for structured and comparative analysis of trends not previously attempted.
A systematic literature review was used to collect and analyze research data, which were extracted from articles indexed in Google Scholar (the most useful search engine in the field of academic research). The keyword ‘sustainable urban development’ was searched in Google Scholar to find articles published during 2012-2022.
To initially look through and evaluate the articles, we conducted an exploratory skimming of each title, abstract, and keywords to get a general understanding of its focus and content. We briefly examined around 10-15 articles per day to get an overview without fully analyzing or assessing each one yet.
The initial search resulted in 790 articles. In deciding which articles to include or exclude from our work, we applied the following criteria:
1) Articles needed to be in English to be understandable to our researchers.
2) They must have mentioned a specific city or country in the title or abstract as our research focused on cases at the city level.
3) Content had to sufficiently relate to dimensions of sustainable urban development based on our skimming of the title, abstract, and keywords.
4) No articles with errors in databases or non-English abstracts were included.
Using these inclusion/exclusion standards, 10.8 percent of the initial 790 articles were excluded, leading to a total number of 705 articles.
The researchers then conducted a more thorough manual review of the remaining 705 articles to determine the country and continent where each city was located. When the full articles could not be retrieved, their abstracts were accessed from other databases by searching titles in Google. The analysis scope for the obtained articles was based on the title, abstract, and keywords in English. Researchers manually extracted the key and specialized words of each article after data collection to determine the dimensions of sustainable urban development.
In the next step, purposeful sampling was used to select 30 experts in the field of urban planning and sustainable development. The selection criteria for these experts included:
1) Holding a Ph.D. degree in urban planning or related fields.
2) Having at least 10 years of work experience and research background in urban planning and sustainable development.
A standardized questionnaire was used to collect expert opinions. The questionnaire included a list of keywords extracted from the reviewed articles, and experts were asked to categorize the keywords based on their relevance to the dimensions of sustainable urban development. This process was conducted separately for each expert, and the final results were reviewed and consolidated using the Delphi consensus technique. After two weeks of reviewing and analyzing the expert responses, five main dimensions were identified: environmental-ecological, economic, socio-cultural, political (managerial-institutional), and demographic (Table 1).
The selection of these dimensions was based on their repeated relevance to sustainable urban development concepts in the reviewed articles and validation by the experts.
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Each of the 705 reviewed articles examined several dimensions of sustainable urban development. Excel was used to facilitate the mental organization of researchers when analyzing data and classifying quantitative and qualitative information of articles as required. The statistical data were based on the number of articles investigating and analyzing the five dimensions of sustainable urban development and their ranking, continents, countries, and publication year.
The pre-trained BERT model, which is based on transformer networks, was utilized to classify the articles based on the five sustainable urban development dimensions examined in the research.The abstracts and titles from the manually categorized literature were compiled into a dataset and split 90/10 into training and test sets. The training data was used to fine-tune the pretrained BERT natural language processing model to classify the abstract texts into one of the five sustainability dimensions or multi-dimensional by tokenizing and encoding the texts. The fine-tuned model was evaluated on the test set using accuracy. This demonstrated the feasibility of using AI text classification techniques like BERT to determine the primary sustainability dimension studied in each article based solely on the abstract and title. Applying automated classification enables more efficient large-scale analysis of the growing literature on sustainable urban development (Figure 1).
This research focused on the review and analysis of sustainable urban development dimensions in continents and countries mentioned in the indexed articles during 20122022. Statistical results showed that the articles followed a fluctuating trend in their discussion of each sustainable urban development dimension in the studied continents over the selected period (Figure 2).
The largest number of articles belonged to the environmental-ecological, sociocultural, economic, political (managerial-institutional), and demographic dimensions of sustainable urban development, respectively.
Among the 705 final articles selected, the largest number on the continental scale belonged to Asia, Europe, Africa, North America, South America, and Oceania, respectively (Figure 3). Overall, 92 countries were investigated, most of which belonged to Europe, Asia, Africa, South America, North America, and Oceania, respectively. Hence, although Asia had the greatest number of articles, European countries reported a greater frequency of case studies in sustainable urban development research.
The number of articles conducted on sustainable urban development followed an increasing trend from 2012 to 2016 and decreased in 2017. This trend increased again from 2018 to 2019 but decreased in 2020, increasing again in 2021 and decreasing in 2022. Research on ecological-environmental, economic, socio-cultural, political (managerial-institutional), and demographic dimensions followed an increasing and regular trend in the first 5, 4, 3, 3, and 2 years of the period from 2012 to 2022, after which the trend were irregular with downward and upward fluctuations.
Statistical results by countryAsia, Europe, Africa, North America, South America, and Oceania allocated 329 articles and 28 countries, 131 articles and 38 countries, 85 articles and 15 countries, 31 articles and 4 countries, 22 articles and 5 countries, and 13 articles and 2 countries to themselves, respectively (Table 2).
| Continent | Countries |
|---|---|
| Asia |
Iran, china, India, Indonesia, Bangladesh, Vietnam, South Korea, HongKong, Japan, United Arab Emi- rates, Sudi Arabia, Malaysia, Nepal, Qatar, Pales- tine, Taiwan, Pakistan, Lebanon, Jordan, SriLanka, Thailand, EastTimor, Bhutan, Myanmar, Cambodia, Afghanistan, Philippines |
| Europe |
Sweden, Russia, Germany, Poland, Turkey, Italy, Uk, Netherlands, Greece, Romania, Czech, Spain, Den- mark, Serbia, France, Norway, Finland, Slovakia, Bul- garia, Macedonia, Estonia, Kosovo, Lithuania, Portu- gal, Belgium, Latvia, Ukraie, Montenegro, Georgia, Azerbaijan, Austria, Croatia, Cyprus, Scotland, Al- bania, Bosnia Herzegovina, Hungary, Switzerland |
| Africa |
Egypt, Nigeria, Ghana, SouthAfrica, Kenya, Mozam- bique, Tanzania, Rwanda, Uganda, Namibia, Zambia, Mauritius, Burundi, Algeria, Morocco |
| North America | US, Canada, Mexico, Cuba |
| South America | Brazil, Argentina, Peru, Chile, Colombia |
| Oceania | Australia, New Zealand |
Among the 38, 28, 15, 5, 4, and 2 countries of Europe, Asia, Africa, South America, North America, and Oceania, 7.89%, 17.86%, 20%, 20%, 25%, and 50% had examined all five dimensions of sustainable urban development, respectively.
Iran, Sweden, Egypt, America, Brazil, and Australia ranked first in Asia, Europe, Africa, North America, South America, and Oceania, respectively, with respective numbers of 131, 24, 27, 22, 12, and 11 articles. Researchers examined all five dimensions of sustainable urban development in Iran, Egypt, America, Brazil, and Australia, while only four dimensions were investigated in Sweden.
Analysis results of sustainable urban development dimensions by each continent AsiaAsia with a share of 46.67% had the largest number of articles in this research because Asia is the most extensive and populous continent, with the highest number of urban inhabitants. By 2030, the population of this continent is projected to increase by 1.1 billion, resulting in a population density in Asia that is 1.5 times higher than the global average. This high population density coupled with rapid urbanization and climate change effects has led to major changes in ecosystems and biodiversity, exerting significant strain on natural ecosystems. Urbanization in Asia is proceeding on an unprecedented scale in human history and will lead to numerous challenges, especially in terms of nutrition, shelter, and employment. Despite the poverty and deprivation in urban areas, population expansion, and the emergence of a middle class, Asian developing countries nevertheless contribute to the market for goods and services (Dutt and Noble, 2004; Le, Chang et al., 2019; Roberts, B. and Kanaley, 2006; Roberts, B. H. and Fisher, 2006). Thus, it is critical to address the environmental-ecological, socio-cultural, economic, political (managerial-institutional), and demographic dimensions of sustainability. The environmental-ecological (n=215), socio-cultural (n=176), economic (n=95), political (managerial-institutional) (n=81), and demographic (n=13) dimensions allocated the highest number of articles to themselves.
The high frequency of articles focusing on the environmental-ecological dimension in Asia can be attributed to the various pressing environmental challenges facing many Asian cities due to rapid urbanization in recent decades, which has exacerbated environmental problems through its negative impacts on the natural environment and ecosystems around urban areas. With Asian cities growing in size and population density, sustainably addressing these environmental degradations has become a significant priority, which explains the large volume of research on the environmental impacts of urbanization in the region.
In addition, Asia has some of the richest and poorest countries in the world. Human welfare has increased with the increase of economic welfare, while environmental welfare has faced a decreasing trend, indicating that Asia countries generally lack sustainable development. In other words, in developing Asian countries, rapid industrialization and high economic growth rates have accelerated environmental degradation (Herath, Udage et al., 2021). Thus, the environmental-ecological, socio-cultural, and economic dimensions are significantly interrelated in the urban space, the importance of which is evident in the number of reviewed articles.
The ability of Asian cities to develop sustainable urban environments over the long term is influenced by the measures they take to promote economic, social, and environmental challenges. In the meantime, although environmental governance and the economic growth rate in Asia can bring about potential strengths, they may also have disadvantages (Peiris, Barth et al., 2012; Ueta and Mori, 2007). Asian countries must reassess their decentralisation, private sector involvement, and community engagement policies in order to enhance the efficiency and efficacy of urban environmental management (Memon, Imura et al., 2006). Thus, The Charter of the International Sustainable Development establishes an intricate connection between broad and specific standards for urban environmental sustainability in the strategies of individual Asian nations. This allows for the comparison of sustainable city strategies across Asia (Ermolina, Matveevskaya et al., 2020).
The socio-cultural dimension received high attention due to many Asian cities facing significant challenges in meeting the basic needs of their rapidly growing urban populations, such as access to housing, healthcare, education, and employment opportunities. Rapid urbanization has also widened inequality between different urban regions and gender groups. Also, Given Asia's fast-paced industrialization and urban growth, the economic dimension saw substantial focus, attracting large influxes of rural migrants moving to cities to pursue jobs and higher wages. However, unintended consequences have included rising inequality, unemployment, and insufficient basic services requiring strategic policy solutions for sustainable urban development.
Given the conditions of Asia, environmental pressures are manifested with the continuation of social problems in the poorer Asian economies, necessitating policy interventions and acceptable technologies because the problems of Asia can have consequences for the whole world (Islam and Jolley, 1996). From another perspective, Sustainable urban development plays a crucial role in urban governance and management by providing direct and indirect infrastructure and services. Additionally, it aids in mitigating the social, environmental, and spatial consequences of urban development (Roberts, B. and Kanaley, 2007). Asian cities move either towards cooperative urban planning or participatory governance (Douglass, 2016). However, Asian urban planning methods are as important as the urban and national histories and the current political and governmental systems.
The political dimension highlighted the need for more strategic long-term planning centered around integrated infrastructure development, regional coordination, and decentralized governance models to effectively address the massive scale of urbanization in Asia and foster inclusive growth. Coordinated multilevel government efforts are needed to manage swift urbanization and resolve socio-economic issues correctly.
Most Asian megacities with the largest population have rapid urbanization and economic growth, highlighting cities' for sustainable development goals (Bai, Roberts et al., 2010). Population growth is expected to be more pronounced in many Asian countries, particularly those with rapidly expanding urban centres and strong economic growth. Consequently, Asia is home to six out of the ten most populous nations (Mohan and Dasgupta, 2005). However, the demographic dimension received fewer articles because population growth in Asia has remained consistently high for decades, causing governments to take high and increasing populations as a given rather than a factor they can significantly influence. Priority has been on accelerating economic development and expanding infrastructure to accommodate growth.
According to the above-mentioned, more research on sustainable urban development is required with a focus on the five interrelated dimensions throughout the Asian continent.
EuropeEurope had the second largest number of articles after Asia, with a share of 31.91%. The most significant number of articles published on sustainable urban development in Europe had focused on environmental-ecological (n=140), socio-cultural (n=99), political (managerial-institutional) (n=67), economic (n=54), and demographic (n=4) dimensions. As a result, Europe leads the world in environmental and sustainable development policies. This is because most governments have adopted sustainable development strategies to improve policy integration and coordination, both vertically and horizontally between various policy levels and sectoral policies. In other words, sustainable development contributes effectively to different welfare-state models in the European Union's coherent social policy path (Steurer and Hametner, 2013). The high frequency of articles dealing with the environmental-ecological dimension in Europe is because of the increasing awareness and strong policy focus among the European public and policymakers on climate change, pollution, and efficient resource use in cities. Strict environmental regulations in Europe require robust research and reporting on the ecological performance of cities, which has helped drive more research emphasis and funding for developing green urban agendas, resulting in numerous studies analyzing European cities from an environmental lens.
European cities surrounded by Asia, Africa, and the Atlantic Ocean are strategically important regarding geopolitics and the global economy (Gaffikin, Cheshire et al., 2019). In the meantime, Europe is experiencing numerous sustainability challenges, social inequalities, demographic changes, climate and environmental challenges, health crises, digital revolution, and rapid technological changes.
Economic issues have also gained research focused on Europe's emphasis on maintaining competitiveness in the global marketplaces and the budgetary constraints European municipalities face. In contrast, the low frequency of articles on demographic challenges reflects that issues related to fast urban population growth and inclusion may need to be more pressing priorities for most European cities. Besides that, European urban centers are generally not witnessing explosive population increases through high birth rates or large-scale in-migration.
On the other hand, since cities provide the driving force of sustainable development in Europe, it is essential to support policymakers, urban stakeholders, and all citizens to ensure a sustainable, fair, and livable future for cities and citizens (Actions, 2021).
The focus on socio-cultural dimensions like the aging population, cultural diversity, and historical preservation in many articles is due to the need to address livability and citizen well-being for European cities, given the challenges of a growing aging demographic and cultural pluralism emerging from immigration. Also, Political dimensions received attention in articles since analyzing governance strategies around performance assessment, public accountability, cross-border partnerships, and fiscal autonomy of local administrations is important for European cities to establish sustainable communities through greater accountability, international cooperation, and fiscal independence.
AfricaAfrica was in third place with the highest number of articles in this research, allocating a share of 12.06% to itself. The environmental-ecological, socio-cultural, economic, political (managerial-institutional), and demographic dimensions were the most frequently studied in 54, 48, 31, 26, and 6 articles, respectively.
The urban population of Africa doubles every 20 years, making urbanization the fastest in this region of the world. Despite its abundant natural resources, this continent should be the wealthiest. However, it continues to experience poverty and is home to 58% of the world's low-income countries, resulting in substantial environmental degradation, institutional inefficiencies, and corruption. Hence, it is imperative to concurrently address physical contexts, as well as social and economic sustainability concerns, in order to attain sustainability and sustainable development in Africa (Bartniczak and Raszkowski, 2018; Plessis, 2001). As stated by Muggah, emerging cities in Africa are fragile and show significant vulnerability to socioeconomic and environmental shocks (Matamanda and Nel, 2020). Therefore, the articles on sustainable urban development in this continent prioritized the environmental-ecological, socio-cultural, and economic dimensions.
The high frequency of articles addressing the environmental-ecological dimension in Africa is due to several issues facing cities on the continent as a result of rapid urbanization, with many cities struggling with inadequate housing, transportation, waste management, and access to clean water and sanitation as urbanization places immense strain on infrastructure and services. Simultaneously, African urban areas are susceptible to the effects of climate change such as heightened occurrences of flooding, heat waves, and droughts. This presents significant obstacles to the achievement of sustainable urban planning and development. Addressing environmental sustainability is thus a pressing priority, as pollution, ecosystem degradation from unplanned development, and natural resource degradation threaten public health and livability. Researchers and donors are attracted to studying these challenges and proposing solutions, with donors focusing funding on related projects, explaining the large number of articles on this dimension.
Furthermore, the high number of articles on the socio-cultural, economic, and political dimensions is because Africa faces considerable social, economic, and institutional challenges exacerbated by rapid urbanization straining government resources, with urban poverty, unemployment, and disease overwhelming cities due to inadequate essential services, housing and infrastructure as informal settlements expand uncontrolled. These severe socio-economic issues are further exacerbated by insufficient jobs and infrastructure against the backdrop of fast urban population growth, requiring coordinated government action and investment critical to effectively address huge socio-economic disparities through urgent political reforms in areas like planning, housing laws, and financing infrastructure development.
The topic of urban infrastructure and its effects on Africa, a continent grappling with extensive poverty, was not prioritised in research and policy discussions for a significant period of time (Pieterse, Parnell et al., 2018). Urban planning, environmentally friendly infrastructure, technologies, and financial support provide African countries with the opportunity to use urbanization for sustainable development. A careful management is required for this urbanisation process, as there is still a need for two-thirds of the investment in African urban infrastructure by 2050 (Ahenkan and Osei-Kojo, 2014; UN-Habitat, 2015). Sustainable growth and development will be realized in Africa only when the issues of justice, sovereignty, and respect for human dignity are addressed, and powerful countries avoid history eradication (Nhamo, 2017). Thus, the sustainable development movement and literature in most urban areas of Africa have largely been formed around the United Nations and have proven effective in expressing political guidelines for SUD implementation. Sustainable urban development requires African cities to save themselves from environmental disasters, leading to poverty reduction and democracy institutionalization (Myers, 2008). However, there are no coordinated development strategies in this continent to ensure suitable living conditions for the population, maintain a high level of environmental quality, and subsequently guarantee sustainability (Boon, 2016; Ndum, Utulu et al., 2016).
Eventually, the paucity of articles on the demographic dimension can be explained by a need for more reliable and up-to-date population data in many African nations, with financial and logistical constraints, meaning statistical censuses and demographic health surveys must be regularly conducted. Rapid urbanization has also occurred recently, outpacing formal planning processes and making it difficult for academics to undertake comprehensive studies focusing on trends, structures, and challenges within African urban demography due to the need for more nuanced population information and analytics. These data deficiencies, therefore, result in fewer scholarly contributions illuminating this critical aspect of sustainable urbanization.
North AmericaNorth America, with a share of 4.4%, was in fourth place concerning the highest number of articles in this research. The environmental-ecological, socio-cultural, political (managerial-institutional), economic, and demographic dimensions were the most frequently studied in 21, 15, 9, 4, and 1 article(s), respectively. The high focus on the environmental-ecological dimension makes sense in the context of urban planning and development trends in North America. The role of active civil society helps explain the prevalence of research on environmental topics in urban studies from the region. Additionally, sustainability in North American cities has long centered around addressing environmental impacts through green building, renewable energy, and climate adaptation. These practical sustainability efforts at the local scale have generated substantial research exploring their merits and challenges.
The North American region is at a critical ecological crossroads (Weis and Krajnc). The majority of North American urban regions' current development patterns need to be more sustainable because they negatively impact environmentally sensitive areas and make it more challenging to offer services because of their low-density, irregular development. However, due to the fragmented nature of local government, strong property rights traditions, and a lack of clear policy direction from higher governmental levels, efforts to plan and manage growth for sustainability have been nearly impossible, making attempts to better control or manage urban sprawl unsuccessful (Reese and Sands, 1970). Hence, researchers prefer to focus on North America's environmental-ecological, socio-cultural, and political (managerial-institutional) dimensions to achieve sustainable urban development.
Furthermore, some of the world's most urbanised and biologically diverse landscapes are found in North America, whose population and economic growth have fueled the recent urban development. On a continental scale, only a small area of land is allocated to urban development in North America (Elmqvist, Fragkias et al., 2013). Also, the low number of articles on the demographic dimension of sustainable urban development in North American published works could be attributed to the population trends in the region being relatively stable and predictable compared to other areas. As population growth and shifts have posed manageable challenges, North American researchers may have focused more on issues linked to other environmental, economic, or socio-cultural aspects of urban sustainability perceived as more pressing or nuanced in their local context, warranting deeper discussion and analysis.
South AmericaSouth America, with a share of 3.12%, was in fifth place concerning the highest number of articles in this research. The socio-cultural, environmental-ecological, political (managerial-institutional), economic, and demographic dimensions were the most frequently studied in 15, 13, 7, 7, and 1 articles, respectively. Over 80% of the population of South America lives in cities, and over 20% of all Latin Americans reside in the major cities of each of the continent's countries. Urban growth in South America has recently been concentrated in medium or small cities, urban centers, or outskirts of urban areas. Most megacities have a large population of homeless people and scattered slums, and this colossal population requires an infrastructure with careful management, from sanitation to transportation (Finlayson, 2016; Warn and Adamo, 2014). The rapid pace of urbanization and economic growth experienced in South America in recent decades has put significant pressure on the environment and ecology of cities, leading to issues like environmental degradation, informal settlements, weak urban governance, and inadequate provision of essential services. As a result, scholars focus research on the environmental-ecological and political/institutional dimensions to examine challenges in these areas arising from rapid growth.
This continent has some of the most significant social and economic inequalities in the world, along with unstable employment patterns, urban sprawl, high levels of urban insecurity, and unequal access and quality of life distribution. Although South America harbours a multitude of highly diverse ecosystems on a global scale, dispersion, loss of vegetation, fragmentation of ecosystems, and waste and water pollution have adversely affected the quality of life in this continent (Faggi, 2015). The uneven nature of economic development across regions has exacerbated income inequality issues, with research on the economic dimension analyzing policies and interventions to promote equitable and inclusive growth to address the socio-economic hardships of poverty, homelessness, and vacant housing faced in urban communities. Meanwhile, the high degree of socio-cultural diversity across and within South American cities, stemming from the presence of indigenous groups and mixes of immigrants, provides rich opportunities for researching topics related to urban identity, social cohesion, and cultural preservation, which likely explains the focus of articles on this dimension.
Similar to other continents, there is a relatively lower research focus on the demographic dimension because urbanization trends have been steady without any significant population spikes that would necessitate attention. Instead, researchers are more concerned with dealing with the pressing socio-cultural, environmental, economic, and institutional challenges that arise due to rapid urbanization.
OceaniaOceania, with a share of 1.84%, was in the last place concerning the highest number of articles in this research. The environmental-ecological, socio-cultural, demographic, political (managerial-institutional), and economic dimensions were the most frequently studied in 10, 6, 2, 1, and 0 articles, respectively. The high proportion of articles focusing on the environmental-ecological dimension in Australia and New Zealand reflects the prominence of environmental issues in these island nations with unique and fragile ecosystems as rapidly urbanizing cities have exacerbated pressures on the natural environment, urban research agendas prioritize understanding human-environment interactions and developing integrated approaches to planning and design that mitigate ecological degradation, These issues, such as water sensitive urban design, green infrastructure, and urban ecology, are clearly demonstrated. In contrast, the lack of research on the economic dimension stems from these countries having stable, developed economies that are not facing as acute urban economic issues as less developed regions, where their cities already have high living standards and strong fundamentals, resulting in less emphasis on traditional topics of urban poverty, inequality, and infrastructure investment with researchers perceiving limited opportunities for impactful work given the relative economic prosperity and fewer disparities.
Economic and social development is the priority in the Pacific Island countries. While being increasingly urbanised, Australia and New Zealand have modest urban densities when compared to the rest of the world. Furthermore, the majority of Australia's and New Zealand's ecosystem services research has concentrated on agricultural ecosystems, indicating a growing attempt to comprehend the characteristics and functions of ecosystem services in urban areas. On the other hand, since urban areas such as New Zealand are at the center of biodiversity, their urban growth may have significant destructive effects on biodiversity in the future (Dyball, Ives et al., 2013), which highlights the importance of and the reason behind more research on the environmental-ecological dimension in this continent. However, considering the growth of some cities in this continent, researchers should also pay more attention to demographic and economic dimensions because agricultural ecosystems contribute significantly to the economy and exports of these countries in addition to environmental impacts.
Dimension-based classification of articles by AIThis phase sought to classify sustainable urban development articles based on the dimensions obtained. In general, Natural Language Processing (NLP) algorithms enable automatic text data analysis, along with the content-based assignment of a set of predetermined classes and classifications to them. NLP lets computers understand human language, using AI to receive input from the real world, analyze it, and reach the defined goal.
This section mainly aimed to systematically categorize the articles into specific and predetermined groups. Thus, the title and abstract of each article were extracted as a representative of its textual data, and the article was then assigned to one to three dimensions.
Figure 4 indicates the general structure of the steps of article classification. The dataset was primarily introduced to the network as input with a specific configuration and structure. Then the words were converted into vectors and provided to the common neural networks in NLP (the transformer BERT network in this study). Finally, the dimension of each article was determined as the research output. Thus, articles were classified through five steps.
Each article included a title, abstract, and dimension, known as an article label. Each article could contain several labels, leading to a multi-label research dataset (Table 3).
| Country | Environmental-Ecological | Socio-cultural | Political | Demographic | Economic | Title | Abstract |
|---|---|---|---|---|---|---|---|
| Iran | 1 | 1 | 0 | 0 | 1 | Modeling urban structure. . . | City has long been regarded as one of the human achievements by civilizations. . . |
| China | 1 | 0 | 0 | 0 | 0 | Simulation of water. . . | The water conflicts between society and ecosystems pose great challenges. . . |
| USA | 0 | 1 | 1 | 0 | 0 | The redevelopment. . . | Cities have huge economic, environmental and social impacts on the world. . . |
| Australia | 1 | 0 | 1 | 0 | 0 | Why is determining. . . | In the age of climate change, for many cities around the globe seeking. |
| Egypt | 1 | 1 | 0 | 0 | 1 | The Challenges. . . | Sustainable urban development (SUD) is influenced by social, cultural, economic. . . |
| Belgium | 0 | 0 | 1 | 0 | 0 | Sustainability indicators. . . | The pursuit of sustainable development as an adaptive process of. . . |
The labels of each data or the research dimensions were in the form of strings. The categorical variables were converted into numerical ones using the One Hot Encoding method to make the dataset labels suitable for network input. Thus, a column was defined for each article according to the number of labels. Values of one and zero showed that the article had or lacked the desired label, respectively (Table 4).
| Title+Abstract | Target List |
|---|---|
|
Modeling urban structure...+City has long been regarded as one of the human achievements by civilizations. . . |
[1, 1, 0, 0, 1] |
|
Simulation of water. . . +The water conflicts between society and ecosystems pose great challenges. . . |
[1, 0, 0, 0, 0] |
|
The redevelopment. . . +Cities have huge economic, environmental and social impacts on the world. . . |
[0, 1, 1, 0, 0] |
|
Why is determining. . . +In the age of climate change, for many cities around the globe seeking. . . |
[1, 0, 1, 0, 0] |
|
The Challenges. . . +Sustainable urban development (SUD) is influ- enced by social, cultural, economic. . . |
[1, 1, 0, 0, 1] |
|
Sustainability indicators. . . +The pursuit of sustainable development as an adaptive process of. . . |
[0, 0, 1, 0, 0] |
The title and abstract of each article were then connected, and the labels were listed in one column. Finally, the extra columns were removed.
Figure 5 shows the frequency of each dimension in the articles.
The dataset was ultimately converted into training and testing parts to build and evaluate the AI model of text classification. Overall, 10% of the data were allocated to testing and 90% to training, leading to 606 and 99 data for model training and testing, respectively.
Text vectorizationThe text of each data must be then converted into a vector by entering the text into a section called tokenize, where each sentence is divided into the smallest meaningful linguistic units. Then each meaningful unit receives a unique number and ID based on a dictionary of words. The numerical ID represents the identity of single words, which finally enter the Vectorization section and become vectors. Since the BERT model was used for article classification in this research, the data sets were converted into a format in which BERT could be trained. Thus, the BERT pre-train model in the transformers library was used. Each tokenized text data was assigned a unique numerical ID, using Bert Tokenizer and encode plus function. All sentences in the dataset are given the same size, and two other required features are also included. Each token is then converted into a tensor by giving each numerical ID to the To Tensor class of the transformers library.
Model training and resultsThe current research has used the 12-layer BERT Base pre-train transformer model in Fine-Tune form. The BERT Base network on a dataset including books with 800 million words and Wikipedia with 2500 million words supervised the training. This model with its trained weights was used for the research classification dataset. Thus, a classification token was chosen for the model, the output was connected to a classifier layer, and training was then performed in the form of supervised learning. In other words, a CLS or classification token, which was a zero vector equal to the length of other sentence tokens, entered the network with zero position after tokenization and vectorization of each data. The effect of other tokens was gradually taken into account when passing through the network layers in the training phase of this zero vector, which changed and became meaningful due to the interactions. Finally, this CLS token was connected to the classifier layer. The last layer provided five features as the final prediction of the dimensions of each article. BCE logistics, Adam, and F1 Score were used for the loss function, optimizer, and evaluation, respectively.
The model had an average of 59% prediction accuracy, which could be increased with more data in the dataset. Finally, the BERT transformer network-based trained model obtained in this research could attribute the dimensions under study to new articles in the field of sustainable urban development.
Half of the world’s continental population currently lives in urban areas, the increasing trend of which will continue in the future. Besides, the modern era is experiencing urbanization on a large global scale due to the concentration of many development projects in cities. Many countries are experiencing high levels of growth, which is particularly true for parts of Asia, Oceania, Africa, and South America. Although urbanization brings good opportunities for citizens, both developing and developed nations face numerous challenges throughout this process as well. Thus, sustainable urban development should contribute as the center of global policy to help humanity address the most critical urban challenges and promote the development and progress of sustainable human life. The analysis of 705 articles in Asia, Europe, Africa, North America, South America, and Oceania confirmed the dependence of sustainable urban development on improving the quality of urban life. Everyone wants to be at the center of economic activity and take advantage of social benefits. Many environmental problems result from overcrowding of different continents because urbanization is the driving force for environmental destruction, the consequences of which affect human health and livelihood, necessitating smart urban management. As highlighted by the articles published during 2012-2022, one of the sustainable urban development dimensions attracted more attention each year based on the prevailing conditions in each continent, country, and city. However, a general review of the articles showed the environmental-ecological, socio-cultural, economic, political (managerialinstitutional), and demographic as the most frequently studied dimensions in the six continents, respectively.
Urban systems can have a successful performance only when the environmental, social, economic, administrative, and demographic dimensions are taken together to achieve sustainable urban development in planning, approvals, and legislation. The review of the selected articles showed that Iran, China, India, Bangladesh, and Hong Kong from Asia, Russia, Turkey, and England from Europe, Egypt, Nigeria, and Ghana from Africa, America from North America, Brazil from South America, and Australia from Oceania were the only countries of these six continents that had investigated all five sustainable urban development dimensions.
Through the research process, the title and abstract of the reviewed articles were considered datasets to train the AI model based on the transformer BERT network. This model can perform effectively as an article classifier in sustainable urban development literature and based on the dimensions obtained in the research. The F1 score was 59% after training and dataset testing, which is favorable considering the number of datasets and dimensions of sustainable urban development, which were considered as labels for the articles. There are scantly labeled academic texts in the field of sustainable urban development. The quality and text classification of AI models can be improved by collecting and labeling more data in this field through future studies with a focus on text classification and articles in the field of urban sustainable development.
Conceptualization, Z.M., MA.M., and K.Z.; methodology, Z.M., MA.M., and K.Z.; programming, MA.M.; data preprocessing, MA.M.; data analysis, MA.M.; investigation, Z.M.; resources, Z.M.; data curation, Z.M.; writing—original draft preparation, Z.M.; writing—review and editing, Z.M., MA.M., and K.Z.; supervision, K.Z. All authors have read and agreed to the published version of the manuscript.
The authors declare that they have no conflicts of interest regarding the publication of the paper.
