Tourism and Internet of Things: A Bibliometric Analysis of Scientific Production from the Scopus Database

Tourism is a very emerging sector in any society, very important in economic terms and in job creation, today any traveler increasingly uses technological means to fully enjoy their trip. The IoT is and increasingly will be a major contributor to smart tourism. To identify the most developed terms in the field of Tourism and Internet of Things, a quantitative analysis was developed in May 2022. This analysis was focused on four hundred and four (404) publications from the Scopus database, published between 2011 and May 4 2022. Before 2011 there were no publications in this area. A bibliometric analysis was performed using the VOSviewer software and a technique of matching terms and co-authorship by authors and countries. Were found 4 clusters for the co-occurrence of terms, 18 clusters for the co-authorship of authors and 6 clusters for the co-authorship of countries. There was a lack of uniformity in the presentation of terms with the same meaning: internet of things, internet of things (iot), iot and internet of thing (iot). This lack of uniformity is probably due to the fact that it is a recent area of investigation.


Introduction
The tourism sector is today a globalized sector that has experienced enormous growth in recent decades. Its impact on the economies of some countries is quite high, having attracted increasing attention from the technology industry. In fact, in parallel with the constant technological evolution, in recent decades, the tourism sector has grown to the point of becoming one of the dominant sectors globally, evolving into a new concept called "Smart Tourism" [1]. However, according to [2], despite the growing interest in this concept, it is still considered lacking in more in-depth explanations to be fully understood, in part because of its great complexity.
Tourism is increasingly information intensive [3][4][5]. However, according to [6], tourism is no longer just information intensive, since information is the fabric of tourism and ubiquitous computing, and universal connectivity, are today an inseparable and blended layer of tourism. In the tourism sector, there is a clear trend towards the adoption and implementation of smart technologies in tourist destinations and tourist attractions in order to achieve an enrichment of tourists' experiences and, in this way, improve their degree of satisfaction [7].
An example of the symbiotic fusion between the tourism sector and the technology sector, and the ability to support the concept of "Smart Tourism" is today the Internet of Things (IoT). According to [8], the loT is an asset due to its ability to integrate various services in the field of tourism.
Although the loT is already having a strong impact on the tourism sector, this sector still has difficulties in taking full advantage of the IoT, which is a technology not yet at a stage of full maturity, in order to achieve an intelligent connection among all actors, having positive and negative aspects, of its use, being pointed out [9].
The tourism industry presents itself as a dense and complex mesh of interactions between multiple actors and multiple phenomena that have to be cooperatively coordinated and managed. And it is in this context that the IoT, according to [10], is a trend and has a potentially disruptive role in the tourism and hospitality industry.
The tourism sector is a highly cooperative ecosystem and it will be through, and only through, cooperation that a reengineering of the sector can be leveraged to support, not only a classic fusion between the physical and the virtual, but the metaverse that today is expected dock to the future of the sector -in this context, IoT logic is a key system to support an omnipresent vision of the tourism sector.
The concept and implementation of a metaverse is not new and one of the most famous cases was the social network called Second Life. This 3D virtual world model is, however, still difficult to implement in the tourism sector, in a generalized way. However, the recent COVID-19 pandemic situation has well demonstrated the potential of the vision of a metaverse, both for consumers and businesses [11 ]. For the future implementation of this concept, the loT will be, in our opinion, the support fabric and the great enabler.
The IoT could also have a very significant boost as fifth-generation (5G) mobile communications becomes a global standard. According to [12], 5G will be one of the biggest drivers for loT growth and adoption. Which, according to [ 13], will accommodate the high need for bandwidth and low end-to-end latency of the loT and, in this way, boost the quality of loT components and their connection to the Internet.
If, on the one hand, the IoT will be able to support a revolution in the tourism and hospitality sector, the success of this revolution will depend on the ability to create applications that, using the IoT, allow a very strong interaction between the tourist and the main tourist services ( e.g. transportation, shopping and hotels), as well as integrating social media, digital marketing, and wearable devices [14]. This need is based on a capacity for total integration and interaction, the vision of a smart city supported by IoT is clearly a large network of cooperation. This need for cooperation raises enormous challenges, from the most technical (e.g. security and privacy) to the most human (e.g. trust between people and organizations to share information).
The concept of IoT is not new, however its application requires a reengineering of the way public infrastructures in cities are thought of, the construction of buildings and, ultimately, how they design hardware and software solutions capable of transforming the way people interact with spaces, services and information in general. Creating a truly immersive experience that transforms the way tourists interact with destinations is today an objective possibility but, at the same time, a challenge that is still far from being a mass reality.
In order to better understand the research that has been developed in the context of IoT applied to the context of tourism, the result of a study is presented that sought to identify the main thematic areas of research in the field of tourism and IoT, using the basis of Scopus data.

IoT and Tourism Related Work
Although the massification of IoT is still far from its maturity, there are already several studies, pilot or experimental applications that have been implemented all over the world, in the context of the tourism and hospitality industry.
In the context of recommender systems, [15] proposes a hybrid system capable of combining implicit collaborative filtering and ontology to recommend personalized loT services to users. Also [16], in a work on "multimodal travel route recommendation algorithm based on the awareness of the Internet of Things", states that the IoT could enable to perceive cross-modal tourism routes and, in this way, help in the creation of more efficient recommendation systems.
In [17], within the scope of the hospitality sector, decisions on the adoption of smart solutions, their existing benefits and limitations are studied, and the various decisionmaking factors that can influence the will to adopt the loT are also compared. In [18], the role of IoT is focused, combined with technologies such as big data analytics to support smart tourism, presenting a blockchain-based smart tourism platform.
In [ 19] the role of IoT is focused on the development of Big Data Tourism Resources Based on 5G Network and IoT. In this work it is pointed out that the loT has a very powerful amount of information, as more and more people, especially young people, prefer to travel intelligently through the IoT.
In [20], the opportunities and challenges of applying the IoT to preserve the culture and revitalization of small cities are focused and on how the IoT can help to revitalize them and give them a new life.
A study that aims to identify the impacts of IoT on the tourism industry and a model is proposed to streamline the industry with the tourist movement, in order to be able to fully analyze the tourist experience is presented in [10].
The potential of IoT for smart tourism combined with 5G and AI is presented in [21 ]. This work focuses on the transformative role of IoT in the tourism industry and how its association with 5G and AI can overcome latency constraints when massive amounts of data to be transported and processed are at stake.
In a work presented in [22], it is mentioned a new social model centered on IoT technology and intelligence where tourism is characterized as an extension of the human lifestyle. This work also focuses on the role ofloT in the development of modem tourism, thanks to its enormous capacity for collecting, storing and processing information.
A study carried out by [23], presents an analysis of the suitability of the smart tourism environment assisted and supported by real-time wireless sensor networks for IoT tourism and its suitability was evaluated.
According to [24], in the process of exploring destinations and their attractions, IoT technology can make the entire tourism process more efficient, as the sensory layer present in the IoT is there to help tourists find and obtain data related to their journey travel and, where access to these systems can be easily done through the mobile devices that tourists have.
In the recent pandemic context, a study carried out by [25] presented the benefits of IoT to improve business performance during the COVID-19 pandemic for the travel and tourism industry in Kelantan, Malaysia. This study concludes that the use of IoT in the travel and tourism industry will benefit by improving its business performance, especially during the COVID-19 pandemic. This study discussed several elements and identify the potential and benefits of using the Internet of Things (loT) to improve business performance, business marketing and customer engagement, and as such, achieving better customer satisfaction.
In the context of a survey analysis on the influence of smart devices and IoT applications on tourism, [26] presents a work that discovers which group of Information and Communication Technologies (ICT) devices impacts tourists and the tourism industry, concluding that when the functionalities of multiple devices are combined, the experience results can be optimized.
In a paper on the use of IoT in hospitality, [27] refers that the adoption of IoT is a differentiating factor in the hospitality industry that facilitates the integration of the digital and real world and allows the creation of competitive advantages and process optimization.
In the context of smart cities and accessible tourism, [28] state that IoT proves to be a key technological point for the development of smart urban environments. In their work, an architecture and practical implementation is proposed, adapted to the use case of accessible tourism, applied to people with physical disabilities.
In the context of sun and beach tourism and the lack of information to satisfy tourists' preferences and ensure their safety, [29] proposes a Social Internet of Things platform to share useful information with tourists.
In the context of heritage spaces, [30] focuses on the potential of IoT to rethink the entire process of supporting the interpretation and enjoyment of heritage, carried out by tourists, presenting a conceptual model that uses IoT as a way of transforming the experience of visiting tourist spaces and transforming the way tourists can access information and services, in symbiosis with the interests of entities promoting the space.
Although there is a wide range of studies and researchers that have focused their attention on the IoT and on the way in which it can leverage the different actors in the tourism and hospitality industry, the set of areas of activity is still too vast and dispersed, in part justified by the enormous scope of what are actors in the context of tourism/act of visiting a given destination in a recreative way. In this way, it becomes important to understand how research is linked and interconnected at the moment and who are the researchers and key topics in the dynamics of the evolution of the use of loT.

Methodology
This paper aimed to identify the most frequently developed topics in the area of Tourism and loT, namely, the evolution of the number of papers published to date and the grouping of topics related to Tourism and IoT.
A search was carried out on May 4, 2022 in the Scopus database. The terms "Tourism" and "Internet of Things" were used, limited to the title, abstract and keywords. As a result of the research, 404 publications were obtained.
A bibliometric analysis was performed and the term co-occurrence and author and country co-authorship technique was used. The unit of analysis was the publication and the variables corresponded to the terms included in the title, abstract and keywords. The extraction of terms was performed using the VOSviewer software, version 1.6.18, in order to build a map that shows the relationships between the various terms and their association with clusters of thematic areas. According to [31 ], this methodology analyzes the distance between the various terms selected, and the shorter the distance between two terms, the stronger the relationship between them. The color map represents the various clusters of thematic areas, and terms with the same color are part of the same cluster and, therefore, are more strongly related to each other compared to binary count terms, which consists of verifying whether the term is present or absent in each analyzed document.

Results
The papers obtained are distributed as follows according to the type of document: 193 are conference paper, 137 are article, 39 conference review, 24 book chapter, 10 review and 1 retracted. Figure 1 shows the number of publications carried out up to the date of the search, May 4, 2022.
It appears that until 2016, scientific publications in the loT and tourism area were in small quantity.
More than 60% of the publications were made in the last three years. And in the first 4 months of 2022 there are already 22 publications.
Considering the analysis of the thematic areas and using the VOSviewer software version 1.6.18 and the technique of co-occurrence of terms, two thousand nine hundred and thirty-two (2932) terms were identified, of which only thirty-seven (37) were identified had a minimum of ten (10) occurrences. The thirty-seven (37) terms were distributed across four ( 4) clusters.
The first cluster, the color red in Fig. 2, consists of eleven (11) terms (5g mobile communications, augmented reality, e-tourism, etourism, internet, internet of things, internet of things (iot), iot, sustainability, sustainable development and virtual reality), associates tourism virtualization and sustainability. The existence of terms whose meaning is the same but to be used with different terminology is verified. Namely, e-tourism and etourism and internet of things, internet of things (iot) and iot.
The second cluster, in green in Fig. 2, consists of ten (10) terms: advanced analytics, artificial intelligence, big data, economics, internet of things technology, leisure industry, machine learning, tourism, tourism development and tourism management, associates the development and management of tourism with some technologies.
The third cluster, in blue in Fig. 2, consists of nine (9) terms: cloud computing, data analytics, data mining, internet of thing (iot), location, smart cities, smart city, smart tourism and tourism industry, this cluster groups concepts associated with smart tourism.
The fourth cluster, in yellow in Fig. 2, consists of seven (7) terms: blockchain, commerce, decision making, digital storage, information management, marketing and service industry, associates terms related to commerce and information management.
For each of the terms, the analysis of how many links, total link strength and number of occurrences was carried out, similarly to what is illustrated in Fig. 3 for the term internet of things. Table 1 illustrates, for each term, how many links, total link strength and number of occurrences.
Analyzing the results presented in Table 1, it appears that the term internet of things is, in a prominent way, the one with the most occurrences, followed by tourism. However, the number of occurrences could be even higher if four different terms with the same meaning were not used: internet of things, internet of things (iot), iot and internet of thing (iot). Due to the fact that it is a recent research area, there is a lack of uniformity in the presentation of terms. Even so, the term internet of things is the most used. Regarding  Fig. 3. Illustration for the term internet of things links and total link strength, they are also the two terms with the highest values. However, the terms smart city and iot appear with the same number of links as the term tourism: 34, despite the fact that the total link strength is lower. Using the author co-authorship technique, one thousand sixty-nine (1069) authors were identified, of which twenty-six (26) had a minimum of three (3) publications. The maximum number of publications per author was four (4), and only six (6) authors had this number of publications. Hence, we opted for a minimum of three (3) publications. Of these twenty-six (26), the connection between them is shown in Fig. 4, where we can see the creation of eighteen (18) clusters by the VOSviewer software. Some of these authors are not linked with others, the largest set of connected items consists of seven (7) items, represented in Fig. 4 by clusters in red and blue. Only four (4) clusters have more than one (1) author, and only two (2)   Using the author co-authoring technique, but with the country as the unit of analysis, of the sixty-seven (67) countries, twenty-three (23) had a minimum of five (5) publications. The software created six (6) clusters, as can be seen from Fig. 5. In this case, the top five (5) by number of publications is China, Italy, India, USA and Russian Federation.

Conclusions
This study aimed to identify the main thematic areas of research in the field of tourism and loT. For this, the Scopus database was used as a source and the VOS viewer software was used, using the bibliometric technique of co-occurrence of terms and co-authorship of authors and countries.
The study concludes that there has been a growing trend of publications in recent years, with 2021 being the year with the most publications in the area of tourism and loT.
When creating the clusters, the software places the terms tourism and internet of things in different clusters. But it puts the term etourism in the same cluster as internet of things.
The first cluster, which includes internet of things, associates the tourism virtualization and sustainability. The second cluster, which includes the term tourism, associates the development and management of tourism with some technologies. The third cluster, groups terms associated with smart tourism, and the last cluster, cluster four, associate terms related to commerce and information management.
Regarding the co-authorship of authors, although one thousand sixty-nine (1069) authors were identified, only twenty-six (26) had a minimum of three (3) publications. The maximum number of publications per author was four (4), and only six (6) authors had this number of publications. The link between the authors is still limited. As for the co-authorship with the country variable, of the sixty-seven (67) countries, twenty-three (23) had a minimum of five (5) publications, with the software having created six (6) clusters, with a significant link between them.
There is the use of four different terms for the same meaning: internet of things, internet of things (iot), iot and internet of thing (iot). Due to the fact that it is a recent research area, there is a lack of uniformity in the presentation of terms. However, the term internet of things is the most used.
One of the limitations of this study is that it is limited to the Scopus database. There are other databases, such as the Web of Science, which are equally important in terms of scope, use and updating.
As such, future investigations may involve other bibliometric analyzes that allow overcoming the limitations of this work, namely, including other databases, such as the Web of Science.