Recent Applications of Smartphone and Smart Glasses in Applied Science and Engineering

Today, more than 3.5 billion people use smartphones worldwide, and this number is anticipated to continue to grow in the future. Smartphones can be used for various purposes; their versatility ranges from fast processing and portability to connectivity with a number of networks to sensors, allowing for the measurement of properties of the device itself and the external environment. Furthermore, smartphones are equipped with intuitive software (S/W) distribution systems and thus have significant benefits associated with small costs when applications are developed to replace existing methods or tools.

Smart glasses or smart goggles are optical head-mounted displays that project a virtual image that is visible to the wearer on top of the real-world view. Smart glasses provide both the intrinsic function of glasses to view objects in front of the user and the functions of a smartphone. Unlike smartphones, smart glasses have a great advantage of freeing both hands of the worker so that they can focus on the work. Therefore, smart glasses can also be used in various fields, including healthcare, training, logistics, and tourism.

The increasing ubiquity of smartphones and smart glasses has the potential to transform how we interact with technology and each other. Many applications of smartphones and smart glasses have been developed in the realm of applied science and engineering for purposes of collecting, storing, analyzing, and visualizing various sets of information and data. This Special Issue of Applied Sciences explores the latest research regarding these cutting-edge devices and their applications in various fields.

One of the key areas of focus in this issue is the use of smartphones and smart glasses in augmented reality (AR), virtual reality (VR), and mixed reality (MR) experiences. With the rise of AR, VR, and MR technologies, these devices are becoming essential tools for immersive entertainment, gaming, education, and training. Researchers in this field are exploring new ways to enhance the user experience, from improving graphics and haptic feedback to developing new interaction methods that allow users to interact with virtual objects in more natural and intuitive ways. Dan et al. [1] investigated the use of MR technology for on-site design experiences in community planning, as the current technical conditions do not allow for the visualization of and interaction with virtual design objects in real environments. An MR design support system (MR-DSS) was introduced for the interactive, on-site 3D visualization of virtual design objects, and a design experiment with sixteen participants was conducted. The results indicate that MR technology can provide designers with intuitive design perceptions, accurate design judgments, and convenient design decisions, effectively improving their on-site design experiences.

Aguirre-Pablo et al. [2] demonstrated the use of four smartphones in slow-motion mode with 960 fps to perform the time-resolved Tomographic Particle Shadow Velocimetry of a vortex ring, using background LED-illuminated diffusers for shadow particle imaging. In the study, the challenges in synchronizing high-speed video capture on smartphones was discussed, and steps to overcome them were presented. The resulting 3-D velocity field is compared to a high-resolution snapshot with four 4k-video cameras using dual-color to encode two time-steps on a single frame, suggesting that this low-cost alternative can be a realistic option for conventional 3-D experimental systems. Alrizq et al. [3] compared the effectiveness of skim reading on mobile and desktop screens and investigated the knowledge gained from the text in a given time. The study involved sixty participants and found that skim reading on a desktop screen leads to improved remembrance of the main ideas of the text compared to reading on a mobile screen. The findings support the concept of satisficing in skim reading.

Another area of interest is the use of smartphones and smart glasses in healthcare. These devices have the potential to revolutionize the way we monitor and manage our health, from tracking fitness and nutrition to monitoring vital signs and delivering personalized medical advice. In this issue, researchers share their latest findings relating to how these devices can be used to improve patient outcomes and reduce healthcare costs. Wu et al. [4] proposed an integrated framework for the diagnosis of wound infection using mobile health technology, based on computer vision approaches using supervised learning techniques and machine learning algorithms. The study demonstrated the effectiveness and reliability of the proposed system through an evaluation of a prospectively collected wound database, achieving a significantly higher accuracy rate than other machine learning approaches for the prediction of wound infection. This system can provide continuous postoperative care for patients undergoing surgical procedures, bridging the care gap and improving patient outcomes.

Oh et al. [5] examined how users engage with and utilize task-based alarm apps, such as apps that require the user to solve math problems or take pictures to dismiss the alarm. The researchers collected in situ usage data from 211,273 US users of the Alarmy app for five months, analyzing alarm usage behaviors depending on the wake-up task. The study revealed significant differences in alarm usage behaviors depending on the wake-up task and key usage patterns that affect the frequent use of hard tasks, which can inform the design of task-based mobile alarms. Kim and Choi [6] reviewed academic papers on the applications of smart glasses and drew conclusions on research trends by year and application fields; product and operating system; sensors; and data visualization, processing, and transfer methods. The results showed that smart glasses are most often used in the healthcare field, particularly in clinical and surgical assistance or to assist mentally or physically disabled persons. The study also showed that the prevalence of research related to smart glasses is steadily increasing, and technological research into the development of smart glasses is being actively conducted.

Smartphones and smart glasses also have new applications in the workplace. With the rise of remote work and telecommuting, these devices are becoming essential tools for communication and collaboration. Researchers in this field are exploring new ways to improve the efficiency and effectiveness of virtual meetings and are also developing new tools for remote collaboration and project management. Smart helmets, like smart glasses, are also being employed in various fields, including the workplace. Choi and Kim [7] systematically reviewed the current status and trends of smart helmet research by analyzing 103 academic research articles published between 2009 and 2020. The results show that the number of smart helmet applications has been rapidly increasing since 2018, with a focus on ensuring the safety of motorcyclists. The most commonly used components for the development of smart helmets are single-board-based modular units and sensors for monitoring human health, with wireless communication technology being used to transmit data to other smart devices or cloud servers.

Overall, the articles in this Special Issue showcase the vast potential of smartphones and smart glasses in a wide range of fields, from entertainment and education to healthcare and the workplace. As these devices continue to evolve and improve, they will undoubtedly play an increasingly important role in our daily lives.