# Applications of Smart Glasses in Applied Sciences: A Systematic Review
## 3 Results  
### Smart Glasses Research Trend  
In this study, the number of research papers was determined based on the year of publication to examine the research trends of smart glasses. Figure 3 shows the number of papers published during the last 6 years, from January 2014 to October 2020. Research related to smart glasses, which had been steadily increasing since 2014, declined in 2017. Because of the release of Google Glass in 2017, the number of published papers has skyrocketted and has been steadily increasing as of 2020. Among the 57 papers, 43 were published after 2017. Of the papers published during the past 6 years, 74% were published during the last 3 years. To analyze the areas in which smart glasses are actively researched, the 57 filtered studies were classified into 7 categories: computer science, healthcare, education, industry, service, social science, and agriculture. During the first stage, we classified them based on seven fields of application, and in the second stage, computer science was classified into human-computer interaction (HCI), object recognition, and visualization, and healthcare was classified into clinical and surgical assistance, disability support, and therapy. In addition, education was divided into nursing, physical training, and physics, and industry was divided into maintenance and safety. Service was divided into culture and tourism and e-commerce, and social science was divided into information security, marketing, and psychology. Finally, agriculture was further categorized as work support (Figure 4). Figure 4: Structure of applied research fields and subfields. Figure 3: Publications per year. Number of articles per year between January 2014 and October 2020. Of the 57 studies in the first category, 21 were healthcare-related studies, with 36% of the 7 areas being the most active. Computer science was included in 11 cases and social science in 7 cases. Industry had six studies, and service had four, which was the smallest number (Figure 5). In the second stage, the subfields in which smart glasses were employed and the corresponding ratios were analyzed (Figure 6). The computer science field is developing HCI [18; 19; 20; 21; 22; 23] as an interaction technology between humans and computers; object recognition [24; 25], which is a technology that recognizes what the user sees, based on a camera; and visualization [8; 26; 27] to visually show data to users (Table 1). There are several research cases in the field of visualiza  
Figure 5: Number of studies based on a study of the application fields. Figure 6: Detailed distribution of smart glass applications. tion. [PERSON] et al. [27] compared Google's Tango tablet with Microsoft's HoloLens smart glasses in the context of their visualization of building information modeling data. For 16 participants, tests were conducted to solve four tasks using two devices, and the evaluations of users, in terms of interior design visualization and visualization of the modeling data, were analyzed. As a result of the analysis, it was found that most users preferred tablets that can enable the sharing of one screen with multiple people. Although smart glasses provided additional hands-free functionality and stability, tablets had a more positive impression on users than smart glasses because of the lack of the feeling of being isolated in the virtual world. Figure 7 shows an augmented reality (AR) view of a space for socializing, which was completed for comparison between tablets and smart glasses. Among the subfields of computer science, HCI had the highest proportion of studies at 55%, followed by visualization at 27%, and object recognition at 18%. To improve the convenience and efficiency using a detailed classification, the research and development of technologies that facilitate interactions between smart glasses and users is actively being pursued, and in particular, it was judged that there is a high level of interest in research on various interactions between users and devices.