Industry 4.0 Supporting Logistics Towards Smart Ports: Benefits, Challenges and Trends Based on A Systematic Literature Review

: Purpose: The fourth industrial revolution has pushed companies, and even seaports, to adapt the way they operate in order to remain competitive in the marketplace. Thus, ports are going from analog to digital, and are on their way to achieving the status of smart ports. The purpose of this paper is to analyze what is already known about smart ports. Design/methodology/approach: A systematic literature review was conducted to identify the contributions of Industry 4.0 to seaport logistics (using the PRISMA method), based on studies present in the SCOPUS and Web of Science databases, both at the bibliometric and content level. Findings: Using this method, it was possible to identify the most used technology of Industry 4.0 in the smart port context, the benefits, and the challenges of the digital transformations in seaports, and the world’s smartest port cities. Curiously, from the universe of studies found, few articles are concerned about the impacts of smart ports on the human factor and on the cities and municipalities where the port is located. Originality/value: This study presents contributions both at the theoretical level (which increases knowledge about the status of some of the ports considered smart), and at the practical level (which aims to help/encourage other ports to start/continue to become increasingly smart).


Introduction
Earth has become an urban planet, and according to Wigginton (as cited in Cambra-Fierro & Pérez, 2022), more than half of the world's people now live in cities, and the proportion is growing.Also, new challenges are emerging every day as a result of the change that is continuously taking place which has forced cities to adapt by incorporating current trends for digitalization and adopting smart solutions within the concept of Industry 4.0 to A smart port uses information and communications technology (ICT) to promote the exchange of information between equipment and infrastructure to make decisions in real time and develop various smart applications ranging from smart vessels to smart containers, smart energy, and smart resources, which consequently promotes the increased performance of the supply chain as a whole (Jugović, Sirotić & Poletan-Jugović, 2022;Rajabi et al., 2019;Yau et al., 2020).Min (2022) states that among the key components of a smart port are smart logistics, which consists of handling cargo with automatic cranes, adoption of the port community network, which promotes communication among the stakeholders of a port, and concern for environmental sustainability.
As Fiorini & Galloro (2022) suggest, the COVID-19 pandemic has demonstrated that smart ports already exist and understand the benefits of this digital transformation.However, some ports still operate traditionally, without yet understanding digitalization and, in some cases, how it can be introduced (Fiorini & Galloro, 2022; Philipp as cited in Meyer, Gerlitz & Henesey, 2021).Thus, it is important to study what already exists in the literature on digital transformation in logistics operations at the seaport level, informing not only academics but also practitioners.This paper is structured as follows: section 2 presents a detailed focus on the objectives and questions that the paper intends to answer; section 3 describes the method used to reach the objectives; section 4 presents the results that were obtained; and, in the end, section 5 presents the discussion, the contributions, the limitations, and future work related to the field under analysis.

Objectives and Methods
This paper was designed with the main objective of gaining knowledge of the state of the art of Industry 4.0 contributions to logistics operations in maritime ports by answering the question: "What contributions and challenges of Industry 4.0 are expected to improve logistics towards smart seaports?"To answer this main question, the authors decided to break it down into eight more specific questions as follows: 1. How has the topic progressed over the years?2. Which are the most influential countries in this field?3. Which are the most influential journals in this area?4. Which are the most respected authors in this area? 5. Which is/are the Industry 4.0 technology(ies) that most influence port logistics?6.What are the benefits and opportunities of digital transformation in ports? 7. What challenges are most often pointed out in this transition?8.Where and which ports are already applying Industry 4.0 technologies?
To achieve these objectives, a systematic literature review (SLR) was performed, since it can be seen as a method used to identify, collect, and analyze available information from different research on a specific topic, utilizing several techniques to minimize errors and providing high-quality evidence (Snyder, 2019;Tranfield, Denyer & Smart, 2003).
Thus, an SLR was conducted to identify the contributions of Industry 4.0 to seaport logistics and provide an overview of the research to date related to this topic.This SLR was conducted according to the approach described by Snyder (2019) and was divided into four phases: designing the review; conducting the review; analyzing; and writing the review.
First, in the design phase, it was necessary to understand the motivation and the importance of the topic for the academy by identifying the research question.Subsequently, the type of approach and methodology to be used was chosen to arrive at the answer to the question posed.Then, in the phase of conducting the review, the keywords and the inclusion and exclusion criteria were decided upon, to ensure that the selection of the final sample was well performed, utilizing the PRISMA (preferred reporting items for systematic reviews and meta-analysis) methodology.In the third phase, analysis, it was decided how the chosen papers would be analyzed.Finally, in the writing phase, it was decided to prepare the review using the PRISMA methodology, following the guides stated in the reports (Liberati, Altman, Tetzlaff, Mulrow, Gøtzsche, Ioannidis et al., 2009;Moher, Liberati, Tetzlaff & Altman, 2009).This approach is designed to support systematic reviews and to report "why the review was done, what the authors did, and what they found" (Page, McKenzie, Bossuyt, Boutron, Hoffmann, Mulrow et al., 2021).

Data Collection
Initially, a search strategy was defined in the scientific databases, SCOPUS and Web of Science.This search took place between December 2022 and January 2023.
The keywords used in the search were divided into three major groups, detailed in each of the columns of Table 1: digital transformation and the whole new era of digitalization and Industry 4.0; logistics operations and the supply chain; and ports.These are the terms used to search within the databases using Boolean operators to link them together ("OR" between lines and "AND" between columns).In an initial search, 132 titles were found, 115 from Scopus and 17 from Web of Science, 15 of which are present in both databases and are referenced as duplicates (information illustrated in Figure 1).The result is 117 articles, to which exclusion criteria were applied, referring to language, publication year, availability (due to lack of funding to read the full article), type of document, and the scope of each document, totaling 24 excluded articles.
The exclusion criteria adopted in the search were as follows: • Language: other than English; • Year restriction: before 2011 (articles between 2011 and January 2023 were included); • Full text of the study not available; • Type of documents: books, book chapters, and conference reviews (type of documents included: articles, conference paper, AND review) Taking the above criteria into account, Table 2 shows the final search strategies used in each database, as well as the number of articles obtained in each case.
From this 93, the title and the abstract were read, and studies not focusing on the scope were also excluded.Finally, 82 remain to be read in full, of which 18 were excluded since some of them were not considered relevant and consistent with the research questions under analysis.
Both the screening and eligibility process was conducted jointly by both authors.In cases of differing opinions, detailed discussions were held to reach a consensus, thus ensuring the integrity and accuracy of our review.This collaborative approach ensured a balanced and thorough assessment of the included studies.

Data Analysis
Figure 3 illustrates how the research questions were answered.Research questions 1, 2, 3, and 4 were answered using bibliometric analysis, while questions 5, 6, 7, and 8 were answered by means of content analysis, with a full reading of the article and analysis of the topic to be investigated).

Results. Systematic Literature Review
In the first phase of analysis, the content of the articles was analyzed with VOSviewer, showing which words were most used in the articles (from the analysis of the titles, abstracts, and authors' keywords).

General Characteristics of the Study (Bibliometric Analysis) 3.1.1. Analysis of Papers per Year
According to the methodology adopted, only studies published from 2011 onward were selected, since that was the year that the concept of Industry 4.0 emerged.
Figure 4 shows the evolution of the number of papers per year, demonstrating that most studies were published in 2022 (21 papers), followed by the year 2021 (17 papers), and 2020 (16 papers).The gradually growth in the number of publications since 2018 indicates increasing interest from the academic community in the field of digital transformation in seaport logistics.

Analysis of the Geographical Distribution of the Papers
Figure 5 shows the 20 countries (of a total of 38 countries) with the most publications in the different journals and conferences, among the papers selected (based on the affiliations of every author, rather than solely the first or corresponding author).By analyzing Figure 5, it can be seen that authors with German affiliation are those who have contributed the most (13 articles), followed by Spanish (11 articles) and Italian (9 articles).The first study published among the selected authors was in 2011 by a German author, which suggests that they contributed early to the academic community in this field.Table 3 shows the journals that contribute most publications out of the 57.IEEE Access and Research in Transportation Business & Management represent the journals that present the greatest number of papers in this area-the digital transformation of logistics in seaports.While the first publishes multidisciplinary and application-oriented articles (IEEE Xplore, 2023), the second publishes in the field of international transport management, in a wide range of aspects, such as sustainability and logistics, among others (Science Direct, 2022).Concerning conferences, we observed no significant differences between them in terms of the number of publications.

Journal Title
No  2020), ports are at the beginning of the fifth generation, marked by the adoption of Industry 4.0 practices, beginning the journey of digital transformation.This digital transformation is undertaken by port stakeholders to overcome challenges such as congestion in ports, the need for faster deliveries, and the growing concern for port sustainability, among others (Boullauazan et al., 2022).To understand the influence of industry 4.0 on the logistics activities of seaports, studies were analyzed according to their integration in the 12 most important technologies of Industry 4.0.These technologies are: IoT (Internet of things); cyber-physical systems (CPS); big data analytics; artificial intelligence (AI); cloud technologies; blockchain; autonomous robots; unmanned aerial vehicles (UAV); additive manufacturing (AM) (3D printing); augmented reality (AR); virtual technologies and simulation; and cybersecurity (Sun et al., 2022).
From the reading and full analysis of the 72 articles included in the study, it could be determined that 12 of them did not refer to any type of the 12 most important technologies, and some conclusions could be drawn from the remaining 60.Appendix A contains a summary of this analysis.
According to the analysis conducted, it can be concluded that the most used and most important technology in Industry 4.0, when applied to the logistics operations of ports, is the Internet of things (IoT), which is present in 82% of the studies selected for analysis, followed by big data analytics with 50%, as can be seen in Figure 6.
An example of the application of the IoT in port logistics is in the case of the port of Hamburg, with the use of sensors to manage ship and vehicle traffic in the port to help managers monitor their movements, thereby reducing carbon emissions and increasing the efficiency of port operations (de la Peña-Zarzuelo et al., 2020).The content of the articles was analyzed with VOSviewer, showing which words were most used in the articles (from the analysis of the titles, abstracts, and author's keywords).Figure 7 illustrates the resulting information by means of a map.The size of the circles represents the number of times the words appear throughout the papers (the larger the circle size of the concept, the more often it appears).Thus, the words that appear most frequently are: "Internet of things," "ports and harbors," "digital transformation," "smart port," "supply chain," "sustainable development," "big data" and "digitalization." As mentioned before, the most predominant technology employed in the digitization of seaport logistics is the Internet of things.This is supported by the VOSviewer visualization in Figure 7, where the significant frequency of the key term "Internet of things" is evident from the sizeable diameter of the circle.

Benefits and Opportunities of Digital Transformation in Seaports
After a literature review, it could be concluded that there is a high number of authors that recognize the importance of digital transformation in seaports.Therefore, the objective of this section is to explain some of the benefits and opportunities found in light of the studies analyzed, grouped in the following table (Table 5).

Challenges of Digital Transformation in Seaports
Each of the seaports faces different problems, and the digital transformation can be a long and challenging process (Jović et al., 2019;Mazzarino, Braidotti, Cociancich, Bottin, La-Monaca, Bertagna et al., 2019).Table 6 presents some barriers to the implementation of digital technologies faced by seaports, found in the previously selected studies.

World's Smartest Port Cities
Although digital transformation is almost a requirement for ports to move forward nowadays, it should be noted that each port is a specific house, with its own characteristics.This makes it normal for the level of digitalization to vary between different ports, as this depends on the size of the port, its traditions, the type of cargo that is handled, and so on (Paulauskas et al., 2021).
Furthermore, it is important for a port to feel the need to become "smarter" through the need to better understand and adapt to market requirements and develop integration with stakeholders (such as the cities where they are located and the port logistics operators), and not just due to the pressure they feel through benchmarking with smart port models (Henríquez, Martínez de Osés & Martínez-Marín, 2022).
The concept of "smartness" in the seaport field is defined by some authors as the level of intelligence of a given port, that is, a smart port has a high level of "smartness," and each port has its own level of "smartness" according to its own needs and characteristics.This "smartness" is linked to the amount of technology adopted by the port, the quality of customer service (market satisfaction at the port level), and the improvement of the economic, social, and environmental area (Gao et al., 2022;Henríquez et al., 2022;Rajabi et al., 2019).
Among the studies analyzed it was found that several authors suggest that port cities are considered leaders in the digitalization of their logistics (the smartest port cities with a high level of "smartness") (Henríquez et al., 2022;Molavi et al., 2020).D'Amico, Szopik-Depczyńska, Dembińska and Ioppolo (2021) mention that some of the leading ports in intelligent logistics are: Rotterdam, Amsterdam, Los Angeles, Antwerp, Montreal, Hamburg, Hainan, Valencia, Stockholm, and Singapore.Chuprina et al. (2022) highlighted the ports of Rotterdam, Qingdao, Singapore, Busan, Xiamen, Shanghai, Antwerp, Hamburg, Tilbury, and Long Beach.Henríquez et al. (2022) emphasize the smart ports considered as benchmarks, such as Singapore, Hamburg, and Rotterdam.The ports of Hamburg and Singapore are also underlined as smart ports by Rajabi et al. (2019) and Di Vaio & Varriale (2019).Baştuğ et al. (2020) pointed out the 10 most innovative ports, namely: Rotterdam, Felixstowe, Singapore, Hamburg, Busan, Le Havre, Hong Kong, Shanghai, Barcelona, and Jebel Ali.

Discussion and Conclusion
Nowadays it is essential to adapt to the context in which we live, and digitalization is one aspect of that adaptation.Digital transformation is increasingly essential for ports, leveraging them to another level of competitive advantage, which can be corroborated by the growing number of publications in the literature since 2018.
As stated by D'Amico et al. ( 2021), the integration of smart technologies with the physical infrastructures of the port and its surroundings is capable of leveraging the logistics of port cities, and several technology companies are investing in port cities, such as IBM, Cisco, Huawei, SAP, etc.
These conclusions allow us to assess the importance of this study conducted on Industry 4.0 technologies in port logistics.After the analysis, it could be understood that the most used technology for the digitalization of seaport logistics is the Internet of things.The same conclusion could be arrived at from the VOSviewer map in Figure 7, since the frequency of the key term for the "Internet of things" is comparable (large diameter of the circle).
Ferretti & Schiavone also present the same conclusion, stating that "Transportation and logistics are one of the main domains of application for IoT" (Atzori as cited in Ferretti & Schiavone, 2016).Additionally, the frequency for the key term "big data" is also comparable to the others, which leads us to conclude that, as in the graphic of Figure 6, it is the second most used technology in this field.
This study presents some impacts of digitalization on seaports.Of the benefits found, those that are most referenced are the increased efficiency of the logistic chain, the reduced environmental impact, and the increased competitiveness, among others.This section (Benefits and Opportunities of Digital Transformation in Seaports) fills the gap stated by Boullauazan et al. (2022) about the benefits of making the port smart, to inform port stakeholders and encourage them to grow to another level.
As concerns challenges, the most referenced one is vulnerability to cyber-attack that a port presents after adopting digital technologies.This section (Challenges of digital transformation in seaports) fills the gap stated by Molavi (2020) about the lack of exploitation of the challenges of digital transformation.However, curiously, from this universe of studies found, few articles are concerned about the impacts of smart ports on the human factor and on the cities and municipalities where the port is located, which is also a gap stated by Molavi (2020).
This study contributes alongside the studies by Tijan et al. (2021) andD'Amico et al. (2021) on the impacts of smart ports and the digital transformation occurring in ports.
To conclude this study, Table 7 shows the main findings for each of the eight research questions.
To answer the main question of this article "What contributions and challenges of Industry 4.0 are expected to improve logistics towards smart seaports?", a systematic literature review was performed, through which it was possible to ascertain that this is an important and fashionable topic nowadays that presents not only advantages but also challenges and that there are various ports that are already considered as smart ports.Thus, this paper presents two contributions, theoretical and practical, which can help both academia and practitioners: 1. Theoretical-which consists of increasing knowledge and clarification of the impacts of digital transformation in seaports; 2. Practical-which aims to encourage other ports to become smart.
This study presents some limitations, as it bases the results presented only on the evidence of the literature.Although it is our intention that the review process should be systematic and impartial, the process of choosing the studies to be included and the respective interpretation of their results can be susceptible to bias, which constitutes a limitation.In addition, the literature is constantly changing, and this is a constantly evolving topic, so a systematic literature review can quickly lose its topicality.As future work, the intention is to investigate the practical context of the ports that are already considered smart, and, consequently, analyze and go into more detail about the impacts of smart ports on the human factor and on the cities and municipalities where the port is located.

Question Findings
i.
How has the topic progressed over the years?
The trend shows an ascending trajectory in the volume of studies since 2018.This upsurge in academic publications indicates intensifying curiosity and focus within the scholarly circle on the digital transformation within the sphere of port logistics.Furthermore, technological advancements may also play a significant role in this trend and its progression.
ii.Which are the most influential countries in this field?Analysis of the studies showed that authors with German affiliations have contributed the most, followed by Spanish and Italian authors.The first article published among the selected authors dates from 2011 and is by a German author, indicating Germany's early contribution to the academic community in this field, perhaps because it was the country where the concept of Industry 4.0 first emerged.

Figure 1 .
Figure 1.Distribution of the papers found in the databases

Figure 2 .
Figure 2. Flowchart of search and selection criteria, based on PRISMA

Figure 3 .
Figure 3.The methodology utilized to analyze and answer the specific questions

Figure 4 .
Figure 4. Number of selected articles, per year

Figure 5 .
Figure 5. Top 20 countries that contributed to the selected publications

Figure 6 .
Figure 6.Percentage of references found to the 12 most important technologies of Industry 4.0 in the studies under analysis

Figure 7 .
Figure 7. VOSviewer: Result-most frequent keywords Engineering and Management, 2024 (www.jiem.org)Article's contents are provided on an Attribution-Non Commercial 4.0 Creative commons International License.Readers are allowed to copy, distribute and communicate article's contents, provided the author's and Journal of Industrial Engineering and Management's names are included.It must not be used for commercial purposes.To see the complete license contents, please visit https://creativecommons.org/licenses/by-nc/4.0/.

Table 3 .
Most active journal, by the number of publications, from the selected ones

3.1.4. Analysis of Most respected Authors and Most Cited Papers Some
of the papers selected for analysis are by more than one author, constituting cooperative work among peers.Table4shows the names and data of the most productive and published authors in the universe under analysis, and the respective number of studies.Jović M., Palau C. E., Tijan E., Voß S., and Heilig L. constitute the most influential authors, having carried out joint work with different peers.For example, as presented above, Heilig L and Voß S. are two of the co-authors of the most cited article among the 72 selected.

.1. The 12 Most Important Technologies of Industry 4.0 Applied to Seaports
According to de la Peña-Zarzuelo et al. (

Table 7 .
Findings for each of the eight research questionsAnnexAnnex A -Analysis of which of the 12 most important technologies are mentioned in each of the studies (cont.).Analysis of which of the 12 most important technologies are mentioned in each of the studies.