Topic Editors

Dr. Zhihan Lv
Department of Game Design, Uppsala University, SE-751 05 Uppsala, Sweden
Prof. Dr. Kai Xu
School of Computer Science Cellphone, National University of Defense Technology, Changsha 410128, China
Prof. Dr. Zhigeng Pan
Digital Media & Interaction Research Center, Hangzhou Normal University, Hangzhou 310012, China

Virtual Reality, Digital Twins, the Metaverse

Abstract submission deadline
31 January 2023
Manuscript submission deadline
31 March 2023
Viewed by
39004

Topic Information

Dear Colleagues,

With the rapid development of modern society, the demand for practicability and intelligence is increasing day by day, and more application technologies are focusing on the development of digital intelligence in the future. The intelligent development of smart manufacturing, smart industry, smart medical, and other fields is the only way to build a smart city in the future. In the future, it will even go further beyond the level of cities and countries to realize intelligent research on the entire universe and explore the origin and development of the universe from a more intelligent perspective.

Virtual reality (VR) contains a variety of information technologies, among which simulation technology has developed in a more extensive direction in recent years. The demand for virtual reality technology in various industries and fields is increasing, and chasing a more extreme sense of immersion is the mainstream of current development. Interactivity is also an important focus of research and development. In complex practical application scenarios, a stable experience is an important consideration in determining the pros and cons of practical applications. Real-time and effective interaction ideas and methods are important evaluation indicators for virtual reality technology.

Digital twin (DT) provides a broader application space for virtual reality and at the same time puts forward higher requirements for the technological progress of virtual reality. In the future, various objects in the virtual world will have more abundant intelligence, which is a necessary condition for them to be able to evolve independently and to map each other with objects in the real world. For applications that already exist and will be developed in the future, the integration of real-world data into the virtual world is critical to the development of digital twin technology. New sensors play a vital role in this, and this will also be the key to whether the digital twin can better develop in coordination with multiple fields.

The exhibition of a variety of virtual achievements indicates that the development of the metaverse is no longer limited to the conceptual level, and the digital twin provides a fundamentally effective way for it. The development of VR, DT, and the Metaverse promote each other, forming a closed-loop mutual push development method. This Topic involves a wide range of multidisciplinary themes and realizes more systematic intelligent and digital development in multiple fields, such as industry, manufacturing, education, aerospace, medical and health, and urban development.

Dr. Zhihan Lv
Prof. Dr. Kai Xu
Prof. Dr. Zhigeng Pan
Topic Editors

Keywords

  • virtual reality
  • augmented reality
  • digital twins
  • Metaverse
  • dynamic modeling
  • 3D technology
  • system integration technology
  • geographic information system
  • medical healthcare
  • Industry 4.0
  • industrial manufacturing
  • intelligent manufacturing
  • smart manufacturing
  • BIM
  • building information modeling

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Applied Sciences
applsci
2.838 3.7 2011 14.9 Days 2300 CHF Submit
Electronics
electronics
2.690 3.7 2012 14.4 Days 2000 CHF Submit
Healthcare
healthcare
3.160 2.0 2013 19.1 Days 2000 CHF Submit
Sensors
sensors
3.847 6.4 2001 15 Days 2400 CHF Submit
Sustainability
sustainability
3.889 5.0 2009 17.7 Days 2200 CHF Submit

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Published Papers (22 papers)

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Review
Study on the Applicability of Digital Twins for Home Remote Motor Rehabilitation
Sensors 2023, 23(2), 911; https://doi.org/10.3390/s23020911 - 12 Jan 2023
Viewed by 461
Abstract
The COVID-19 pandemic created the need for telerehabilitation development, while Industry 4.0 brought the key technology. As motor therapy often requires the physical support of a patient’s motion, combining robot-aided workouts with remote control is a promising solution. This may be realised with [...] Read more.
The COVID-19 pandemic created the need for telerehabilitation development, while Industry 4.0 brought the key technology. As motor therapy often requires the physical support of a patient’s motion, combining robot-aided workouts with remote control is a promising solution. This may be realised with the use of the device’s digital twin, so as to give it an immersive operation. This paper presents an extensive overview of this technology’s applications within the fields of industry and health. It is followed by the in-depth analysis of needs in rehabilitation based on questionnaire research and bibliography review. As a result of these sections, the original concept of controlling a rehabilitation exoskeleton via its digital twin in the virtual reality is presented. The idea is assessed in terms of benefits and significant challenges regarding its application in real life. The presented aspects prove that it may be potentially used for manual remote kinesiotherapy, combined with the safety systems predicting potentially harmful situations. The concept is universally applicable to rehabilitation robots. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Study Protocol
A Study Protocol to Evaluate the Effects of Vestibular Training on the Postural Control of Healthy Adults Using Virtual Reality
Appl. Sci. 2022, 12(23), 11937; https://doi.org/10.3390/app122311937 - 23 Nov 2022
Viewed by 406
Abstract
Postural instability is a common symptom of vestibular dysfunction due to an insult to the vestibular system. Vestibular rehabilitation is effective in decreasing dizziness and visual symptoms, and improving postural control through several mechanisms, including sensory reweighting. As part of the sensory reweighting [...] Read more.
Postural instability is a common symptom of vestibular dysfunction due to an insult to the vestibular system. Vestibular rehabilitation is effective in decreasing dizziness and visual symptoms, and improving postural control through several mechanisms, including sensory reweighting. As part of the sensory reweighting mechanisms, vestibular activation training with headshake activities influences vestibular reflexes. However, combining challenging vestibular and postural tasks to facilitate more effective rehabilitation outcomes is underutilized. Our research goal is to develop a virtual reality vestibular rehabilitation method for vestibular-postural control in neurological populations with vestibular and/or sensorimotor control impairment. The NeuroCom® SMART Balance Master (Natus Medical Inc., Pleasanton, CA, USA), which was used in a prior study, is expensive and bulky. Hence, a novel study protocol is established in this paper with the detailed objectives and pre-/post-intervention data analysis pipeline (ANOVA, t-test, post hoc analysis, etc.) involving modern off-the-shelf sensors and custom instrumentation (electromyography, electrooculography, video head impulse testing, force plates, and virtual reality headsets). It is expected that the training will significantly decrease vestibuloocular reflex gains and eye movement variability, as well as reweight the somatosensory ratio, finetune postural muscle activation, and consequently improve postural flexibility and produce a faster automatic postural response. The findings may have implications for the future development of vestibular rehabilitation protocols. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
User Performance in Virtual Reality Environments: The Capability of Immersive Virtual Reality Systems in Enhancing User Spatial Awareness and Producing Consistent Design Results
Sustainability 2022, 14(21), 14129; https://doi.org/10.3390/su142114129 - 29 Oct 2022
Cited by 2 | Viewed by 599
Abstract
Spatial decision-making in different virtual environments may vary based on the levels of spatial awareness experienced within Virtual Reality (VR) systems. Features and characteristics of VR systems may act as facilitators or distractors of spatial awareness, which can result in extreme variations in [...] Read more.
Spatial decision-making in different virtual environments may vary based on the levels of spatial awareness experienced within Virtual Reality (VR) systems. Features and characteristics of VR systems may act as facilitators or distractors of spatial awareness, which can result in extreme variations in user spatial decisions. This research explored the capability of an Immersive Virtual Reality Interactive Environment (IVRIE) and a desktop-based VR (DT system) in reducing extreme variations in spatial decisions and inconsistent design results. Users’ spatial decisions, performance, and design results in both systems were studied regarding the impact of these two systems’ features on users, including the sense of immersion, types of interaction, and usage of eye-level view in spatial designs. The design results produced in both systems were compared considering the types of enclosure, surface texture, scale, and spatial function. Descriptive and inferential statistical comparisons and testing using quantitative and qualitative data were applied to determine participants’ performance regarding the production of spatial outliers in each system. The results showed that IVRIE was more effective than the DT system fostering a consistency of space sizes and reducing outliers. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
Real-Time Foreign Object and Production Status Detection of Tobacco Cabinets Based on Deep Learning
Appl. Sci. 2022, 12(20), 10347; https://doi.org/10.3390/app122010347 - 14 Oct 2022
Viewed by 368
Abstract
Visual inspection plays an important role in industrial production and can detect product defects at the production stage to avoid major economic losses. Most factories mainly rely on manual inspection, resulting in low inspection efficiency, high costs, and potential safety hazards. A real-time [...] Read more.
Visual inspection plays an important role in industrial production and can detect product defects at the production stage to avoid major economic losses. Most factories mainly rely on manual inspection, resulting in low inspection efficiency, high costs, and potential safety hazards. A real-time production status and foreign object detection framework for smoke cabinets based on deep learning is proposed in this paper. Firstly, the tobacco cabinet is tested for foreign objects based on the YOLOX, and if there is a foreign object, all production activities will be immediately stopped to avoid safety and quality problems. Secondly, the production status of tobacco cabinet is judged to determine whether it is in the feeding state by the YOLOX position locating method and canny threshold method. If it is not in the feeding state, then the three states of empty, full, and material status of the tobacco cabinet conveyor belt are judged based on the ResNet-18 image classification network. Ultilizing our proposed method, the accuracy of foreign object detection, feeding state detection and the conveyor belt of tobacco cabinet state detection are 99.13%, 96.36% and 95.30%, respectively. The overall detection time was less than 1 s. The experimental results show the effectiveness of our method. It has important practical significance for the safety, well-being and efficient production of cigarette factories. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
Septoplasty Effect on the Enhancement of Airflow Distribution and Particle Deposition in Nasal Cavity: A Numerical Study
Healthcare 2022, 10(9), 1702; https://doi.org/10.3390/healthcare10091702 - 05 Sep 2022
Viewed by 827
Abstract
The surgery outcomes after fixing nasal airway obstruction (NAO) are sometimes not satisfactory in improving ventilations of airflow. A case study is presented in this paper with computational fluid dynamics applied to determine the key factors for successful septoplasty plans for a patient [...] Read more.
The surgery outcomes after fixing nasal airway obstruction (NAO) are sometimes not satisfactory in improving ventilations of airflow. A case study is presented in this paper with computational fluid dynamics applied to determine the key factors for successful septoplasty plans for a patient with a deviated nasal septum. Specifically, airflow, as well as particle transport and deposition were predicted in a pre-surgery nasal cavity model reconstructed from patient-specific Computer Tomography (CT) images and two post-surgery nasal cavity models (i.e., VS1 and VS2) with different virtual surgery plans A and B. Plan A corrected the deviated septal cartilage, the perpendicular plate of the ethmoid bone, vomer, and nasal crest of the maxilla. Plan B further corrected the obstruction in the nasal vestibule and caudal nasal septal deviation based on Plan A. Simulations were performed in the three nose-to-throat airway models to compare the airflow velocity distributions and local particle depositions. Numerical results indicate that the VS2 model has a better improvement in airflow allocation between the two sides than the VS1 model. In addition, the deposition fractions in the VS2 model are lower than that in both the original and VS1 models, up to 25.32%. The better surgical plan (i.e., Plan B) reduces the particle deposition on the convex side, but slightly increases the deposition on the concave side. However, the overall deposition in the nasal cavity is reduced. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
Design of a Digital Twin Training Centre for an Industrial Robot Arm
Appl. Sci. 2022, 12(17), 8862; https://doi.org/10.3390/app12178862 - 03 Sep 2022
Viewed by 803
Abstract
The Cyber-Physical and Intelligent Robotics Laboratory has been digitally recreated, and it includes all the key elements that allow 6-axis industrial robots to perform PTP, LIN, and CIRC motions. Furthermore, the user can create a program with these motion types. The human–machine interface [...] Read more.
The Cyber-Physical and Intelligent Robotics Laboratory has been digitally recreated, and it includes all the key elements that allow 6-axis industrial robots to perform PTP, LIN, and CIRC motions. Furthermore, the user can create a program with these motion types. The human–machine interface is also integrated into our system. It can also assist SMEs in developing their in-house training. After all, training on an industrial robot unit does not entail installation costs within the facility. Nor are there any maintenance and servicing costs. Since the lab is digital, additional robot units can be added or removed. Thus, areas for training or production can be pre-configured within each facility. Because of the customizability and virtual education format, there is no room capacity problem, and trainees can participate in the exercises in parallel. Exercises were also conducted to evaluate the program’s impact on teaching, and the results showed that using machine units can improve teaching. Even today’s digital labs cannot physically convey the sense of space or the relative weights of different elements in virtual space. Even with these features, individuals can operate a machine more effectively than relying solely on traditional, non-interactive demonstration materials. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
Adaptive Points Sampling for Implicit Field Reconstruction of Industrial Digital Twin
Sensors 2022, 22(17), 6630; https://doi.org/10.3390/s22176630 - 02 Sep 2022
Cited by 1 | Viewed by 767
Abstract
Nowadays, the digital twin (DT) plays an important role in Industry 4.0. It aims to model reality in the digital space for further industrial maintenance, management, and optimization. Previously, many AI technologies have been applied in this field and provide strong tools to [...] Read more.
Nowadays, the digital twin (DT) plays an important role in Industry 4.0. It aims to model reality in the digital space for further industrial maintenance, management, and optimization. Previously, many AI technologies have been applied in this field and provide strong tools to connect physical and virtual spaces. However, we found that single-view 3D reconstruction (SVR) for DT has not been thoroughly studied. SVR can generate 3D digital models of real industrial products from just a single image. The application of SVR technology would bring convenience, cheapness, and robustness to modeling physical objects in digital space. However, the existing SVR methods cannot perform well in the reconstruction of details, which is indispensable and challenging in industrial products. In this paper, we propose a new detail-aware feature extraction network based on a feature pyramid network (FPN) for better detail reconstruction. Then, an extra network is designed to combine convolutional feature maps from different levels. Moreover, we also propose a novel adaptive points-sampling strategy to adaptively change the learning difficulty according to the training status. This can accelerate the training process and improve the fine-tuned network performance as well. Finally, we conduct comprehensive experiments on both the general objects dataset ShapeNet and a collected industrial dataset to prove the effectiveness of our methods and the practicability of the SVR technology for DT. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
WUAD (Wheelchair User Assisted Design): A VR-Based Strategy to Make Buildings More Accessible
Appl. Sci. 2022, 12(17), 8486; https://doi.org/10.3390/app12178486 - 25 Aug 2022
Viewed by 615
Abstract
Accessibility regulations towards building design and public places are more restrictive than in past years. Along with energy efficiency, accessibility is one of the pillars of an optimal building design. However, even buildings adapted for actual regulations are not always optimal, and there [...] Read more.
Accessibility regulations towards building design and public places are more restrictive than in past years. Along with energy efficiency, accessibility is one of the pillars of an optimal building design. However, even buildings adapted for actual regulations are not always optimal, and there is still much to do to avoid adding more difficulties for people with disabilities. We proposed a wheelchair-user-assisted design methodology based on iterative bidirectional communication between a wheelchair simulator user and the building designer to reach the optimum specifications for an accessibility-friendly design. First-hand experience may be crucial to detect obstacles hardly noticeable to people with no impairments. To this end, VR technology was employed along with the mentioned wheelchair simulator to show the advantages of this kind of device when working on real-life experiences. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
Understanding the Effects of Virtual Reality System Usage on Spatial Perception: The Potential Impacts of Immersive Virtual Reality on Spatial Design Decisions
Sustainability 2022, 14(16), 10326; https://doi.org/10.3390/su141610326 - 19 Aug 2022
Cited by 4 | Viewed by 1307
Abstract
The main component of any Virtual Reality (VR) system is the human user. The ways in which a VR system shapes human experience can affect design outcomes. This research explores the differences in spatial perception between an immersive Virtual Reality Interactive Environment (IVRIE) [...] Read more.
The main component of any Virtual Reality (VR) system is the human user. The ways in which a VR system shapes human experience can affect design outcomes. This research explores the differences in spatial perception between an immersive Virtual Reality Interactive Environment (IVRIE) and traditional Virtual Reality (also known as a desktop-based Virtual Reality system, abbreviated herein as the DT system). Spatial perception and the cognition of the spatial factors of virtual spaces were studied based on different features of the two systems, including the sense of immersion, forms of interaction, experience of human scale, and movement through virtual spaces. This study focused on determining how users’ spatial decision making and performance were affected by differences in spatial perception created by the IVRIE and DT systems. Factors examined included the differences between and within the two virtual systems, based on differences in texture, system usage sequence, and the complexity of the experiential/spatial guidelines. Descriptive and inferential statistical testing using quantitative and qualitative data were used to find differences in spatial perception and decision making. The results showed significant space size variations produced by participants between and within the two different VR systems. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
Effect of Visually Induced Motion Sickness from Head-Mounted Display on Cardiac Activity
Sensors 2022, 22(16), 6213; https://doi.org/10.3390/s22166213 - 18 Aug 2022
Viewed by 769
Abstract
Head-mounted display (HMD) virtual reality devices can facilitate positive experiences such as co-presence and deep immersion; however, motion sickness (MS) due to these experiences hinders the development of the VR industry. This paper proposes a method for assessing MS caused by watching VR [...] Read more.
Head-mounted display (HMD) virtual reality devices can facilitate positive experiences such as co-presence and deep immersion; however, motion sickness (MS) due to these experiences hinders the development of the VR industry. This paper proposes a method for assessing MS caused by watching VR content on an HMD using cardiac features. Twenty-eight undergraduate volunteers participated in the experiment by watching VR content on a 2D screen and HMD for 12 min each, and their electrocardiogram signals were measured. Cardiac features were statistically analyzed using analysis of covariance (ANCOVA). The proposed model for classifying MS was implemented in various classifiers using significant cardiac features. The results of ANCOVA reveal a significant difference between 2D and VR viewing conditions, and the correlation coefficients between the subjective ratings and cardiac features have significant results in the range of −0.377 to −0.711 (for SDNN, pNN50, and ln HF) and 0.653 to 0.677 (for ln VLF and ln VLF/ln HF ratio). Among the MS classification models, the linear support vector machine achieves the highest average accuracy of 91.1% (10-fold cross validation) and has a significant permutation test outcome. The proposed method can contribute to quantifying MS and establishing viewer-friendly VR by determining its qualities. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Review
Therapeutic Use of VR Serious Games in the Treatment of Negative Schizophrenia Symptoms: A Systematic Review
Healthcare 2022, 10(8), 1497; https://doi.org/10.3390/healthcare10081497 - 09 Aug 2022
Viewed by 892
Abstract
Schizophrenia is a chronic brain disorder that affects 1 in every 300 people worldwide. This study intended to perform a systematic review to describe the state-of-the-art of interventions involving patients with negative symptoms of schizophrenia that use Virtual Reality (VR) games as a [...] Read more.
Schizophrenia is a chronic brain disorder that affects 1 in every 300 people worldwide. This study intended to perform a systematic review to describe the state-of-the-art of interventions involving patients with negative symptoms of schizophrenia that use Virtual Reality (VR) games as a complement to therapy, and to analyze the key features of such games. Literature research was conducted in three databases, namely, the Institute of Electrical and Electronics Engineers (IEEE), Scopus, and PubMed, to identify relevant publications dated from 2010 to 2021. Of the initial 74 publications found, only 11 satisfied the eligibility requirements and were included in this study. The results were then organized and displayed in a flow diagram. Overall, the results from the studies suggest that the use of VR in therapies enables an increase in social skills and a decrease in anxiety symptoms. The use of such technology in therapy has proven to be effective, although it still lacks features to provide better long-term results. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
Building Korean DMZ Metaverse Using a Web-Based Metaverse Platform
Appl. Sci. 2022, 12(15), 7908; https://doi.org/10.3390/app12157908 - 07 Aug 2022
Cited by 1 | Viewed by 1511
Abstract
Metaverse is a compound word of “Meta” and “Universe”, meaning a world that transcends reality, a new virtual world. Due to the COVID-19 pandemic, non-face-to-face further accelerated the activation of the Metaverse. The Metaverse has the attractiveness of arousing user interest, high service [...] Read more.
Metaverse is a compound word of “Meta” and “Universe”, meaning a world that transcends reality, a new virtual world. Due to the COVID-19 pandemic, non-face-to-face further accelerated the activation of the Metaverse. The Metaverse has the attractiveness of arousing user interest, high service scalability, and the potential to combine multiple revenue models. Therefore, many industries are adopting the Metaverse. The Republic of Korea has been on a ceasefire, since 1953, after the Korean War. After the war, the DMZ was decided in an area of 2 km from north to south (total of 4 km), centered on the Military Demarcation Line (MDL). The DMZ area is the largest nature conservation area in Asia and a military area where public access is strictly restricted. The Ministry of Unification is trying to reduce tensions and establish peace in the DMZ area by raising the interest of Korean people, as well as people around the world, through the DMZ Metaverse application. The Korean government has its own e-Government framework and cloud operating environments. In order to adopt the Metaverse to Korean government agencies and operate them sustainably, it is essential to support the e-Government framework and the cloud environments. In this paper, the design features, architecture, models, and functions of OnTwins, a Metaverse platform serviceable in the Korean government IT operating environment, are elaborated in detail. The DMZ Metaverse public service built on the platform will also be introduced. Finally, after comparing it with other Metaverse platforms, future research directions are discussed. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
Data Collection Framework for Context-Aware Virtual Reality Application Development in Unity: Case of Avatar Embodiment
Sensors 2022, 22(12), 4623; https://doi.org/10.3390/s22124623 - 19 Jun 2022
Viewed by 1235
Abstract
Virtual Reality (VR) has been adopted as a leading technology for the metaverse, yet most previous VR systems provide one-size-fits-all experiences to users. Context-awareness in VR enables personalized experiences in the metaverse, such as improved embodiment and deeper integration of the real world [...] Read more.
Virtual Reality (VR) has been adopted as a leading technology for the metaverse, yet most previous VR systems provide one-size-fits-all experiences to users. Context-awareness in VR enables personalized experiences in the metaverse, such as improved embodiment and deeper integration of the real world and virtual worlds. Personalization requires context data from diverse sources. We proposed a reusable and extensible context data collection framework, ManySense VR, which unifies data collection from diverse sources for VR applications. ManySense VR was implemented in Unity based on extensible context data managers collecting data from data sources such as an eye tracker, electroencephalogram, pulse, respiration, galvanic skin response, facial tracker, and Open Weather Map. We used ManySense VR to build a context-aware embodiment VR scene where the user’s avatar is synchronized with their bodily actions. The performance evaluation of ManySense VR showed good performance in processor usage, frame rate, and memory footprint. Additionally, we conducted a qualitative formative evaluation by interviewing five developers (two males and three females; mean age: 22) after they used and extended ManySense VR. The participants expressed advantages (e.g., ease-of-use, learnability, familiarity, quickness, and extensibility), disadvantages (e.g., inconvenient/error-prone data query method and lack of diversity in callback methods), future application ideas, and improvement suggestions that indicate potential and can guide future development. In conclusion, ManySense VR is an efficient tool for researchers and developers to easily integrate context data into their Unity-based VR applications for the metaverse. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Review
Ship’s Digital Twin—A Review of Modelling Challenges and Applications
Appl. Sci. 2022, 12(12), 6039; https://doi.org/10.3390/app12126039 - 14 Jun 2022
Cited by 4 | Viewed by 1126
Abstract
The Ship’s Digital Twin (SDT) is a digital record of a ship’s behaviour or a software clone, which can be used to simulate scenarios that are expensive or hardly feasible to perform on a real object and especially in real time. The purpose [...] Read more.
The Ship’s Digital Twin (SDT) is a digital record of a ship’s behaviour or a software clone, which can be used to simulate scenarios that are expensive or hardly feasible to perform on a real object and especially in real time. The purpose of the SDT is to achieve cost reduction, obtain timely warnings of irregularities, and optimise individual ship system performances or the operation of the whole ship and to assist ship management. The aim of this paper is to describe the concept of the SDT and clarify some perplexities that may occur from initial introduction to concept. To that end, the paper identifies the steps in the SDT formulation process and methods used in each step of the process. Furthermore, a four-step iterative procedure for the SDT development is proposed. The applications of the concept are numerous, and some of them are presented in a review analysis in this paper. The presented analysis leads to a conclusion that should give some direction to future research in this area. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Review
Applications of Digital Twin across Industries: A Review
Appl. Sci. 2022, 12(11), 5727; https://doi.org/10.3390/app12115727 - 04 Jun 2022
Cited by 5 | Viewed by 3616
Abstract
One of the most promising technologies that is driving digitalization in several industries is Digital Twin (DT). DT refers to the digital replica or model of any physical object (physical twin). What differentiates DT from simulation and other digital or CAD models is [...] Read more.
One of the most promising technologies that is driving digitalization in several industries is Digital Twin (DT). DT refers to the digital replica or model of any physical object (physical twin). What differentiates DT from simulation and other digital or CAD models is the automatic bidirectional exchange of data between digital and physical twins in real-time. The benefits of implementing DT in any sector include reduced operational costs and time, increased productivity, better decision making, improved predictive/preventive maintenance, etc. As a result, its implementation is expected to grow exponentially in the coming decades as, with the advent of Industry 4.0, products and systems have become more intelligent, relaying on collection and storing incremental amounts of data. Connecting that data effectively to DTs can open up many new opportunities and this paper explores different industrial sectors where the implementation of DT is taking advantage of these opportunities and how these opportunities are taking the industry forward. The paper covers the applications of DT in 13 different industries including the manufacturing, agriculture, education, construction, medicine, and retail, along with the industrial use case in these industries. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
Home Environment Augmented Reality System Based on 3D Reconstruction of a Single Furniture Picture
Sensors 2022, 22(11), 4020; https://doi.org/10.3390/s22114020 - 26 May 2022
Viewed by 1000
Abstract
With the popularization of the concept of “metaverse”, Augmented Reality (AR) technology is slowly being applied to people’s daily life as its underlying technology support. In recent years, rapid 3D reconstruction of interior furniture to meet AR shopping needs has become a new [...] Read more.
With the popularization of the concept of “metaverse”, Augmented Reality (AR) technology is slowly being applied to people’s daily life as its underlying technology support. In recent years, rapid 3D reconstruction of interior furniture to meet AR shopping needs has become a new method. In this paper, a virtual home environment system is designed and the related core technologies in the system are studied. Background removal and instance segmentation are performed for furniture images containing complex backgrounds, and a Bayesian Classifier and GrabCut (BCGC) algorithm is proposed to improve on the traditional foreground background separation technique. The reconstruction part takes the classical occupancy network reconstruction algorithm as the network basis and proposes a precise occupancy network (PONet) algorithm, which can reconstruct the structural details of furniture images, and the model accuracy is improved. Because the traditional 3D registration model is prone to the problems of model position shift and inaccurate matching with the scene, the AKAZE-based tracking registration algorithm is improved, and a Multiple Filtering-AKAZE (MF-AKAZE) based on AKAZE is proposed to remove the matching points. The matching accuracy is increased by improving the RANSAC filtering mis-matching algorithm based on further screening of the matching results. Finally, the system is verified to realize the function of the AR visualization furniture model, which can better complete the reconstruction as well as registration effect. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
Mixed-Reality-Enhanced Human–Robot Interaction with an Imitation-Based Mapping Approach for Intuitive Teleoperation of a Robotic Arm-Hand System
Appl. Sci. 2022, 12(9), 4740; https://doi.org/10.3390/app12094740 - 08 May 2022
Cited by 1 | Viewed by 1444
Abstract
This paper presents an integrated mapping of motion and visualization scheme based on a Mixed Reality (MR) subspace approach for the intuitive and immersive telemanipulation of robotic arm-hand systems. The effectiveness of different control-feedback methods for the teleoperation system is validated and compared. [...] Read more.
This paper presents an integrated mapping of motion and visualization scheme based on a Mixed Reality (MR) subspace approach for the intuitive and immersive telemanipulation of robotic arm-hand systems. The effectiveness of different control-feedback methods for the teleoperation system is validated and compared. The robotic arm-hand system consists of a 6 Degrees-of-Freedom (DOF) industrial manipulator and a low-cost 2-finger gripper, which can be manipulated in a natural manner by novice users physically distant from the working site. By incorporating MR technology, the user is fully immersed in a virtual operating space augmented by real-time 3D visual feedback from the robot working site. Imitation-based velocity-centric motion mapping is implemented via the MR subspace to accurately track operator hand movements for robot motion control and enables spatial velocity-based control of the robot Tool Center Point (TCP). The user control space and robot working space are overlaid through the MR subspace, and the local user and a digital twin of the remote robot share the same environment in the MR subspace. The MR-based motion and visualization mapping scheme for telerobotics is compared to conventional 2D Baseline and MR tele-control paradigms over two tabletop object manipulation experiments. A user survey of 24 participants was conducted to demonstrate the effectiveness and performance enhancements enabled by the proposed system. The MR-subspace-integrated 3D mapping of motion and visualization scheme reduced the aggregate task completion time by 48% compared to the 2D Baseline module and 29%, compared to the MR SpaceMouse module. The perceived workload decreased by 32% and 22%, compared to the 2D Baseline and MR SpaceMouse approaches. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
‘Sustainable’ Recording and Preservation of Zangniang Stupa and Sangzhou Lamasery in Qinghai, China with Heritage Building Information Model
Sustainability 2022, 14(8), 4549; https://doi.org/10.3390/su14084549 - 11 Apr 2022
Viewed by 812
Abstract
This paper research and discusses the ‘sustainable’ workflow and heritage recording method of historic building information modelling (HBIM) for Chinese Tibetan architecture and pagodas and explains the vital role of recording heritage information to protect cultural relics. Considering the Tibetan Buddhist Pagoda in [...] Read more.
This paper research and discusses the ‘sustainable’ workflow and heritage recording method of historic building information modelling (HBIM) for Chinese Tibetan architecture and pagodas and explains the vital role of recording heritage information to protect cultural relics. Considering the Tibetan Buddhist Pagoda in Yushu, Qinghai, China, this paper explores the collaborative modelling mechanism and ideas between heritage surveying and scanning information and software, and the problems of these two methods. Through research, we have obtained successful cases of HBIM based on field scanning and mapping, online software collaborative modelling (Rhino, Bentley, Autodesk Computer-Aided Design), sustainable management, and display. It is an information model constructed according to construction logic and accurate information and one that realises sustainable and full-cycle recording functions by continuous recording, updating, and iterating. This method removes a limitation of HBIM in that it considers one-time information construction and delivery mode but does not consider and explore sustainable recording work. It will significantly promote more records on the heritage information of Tibetan architecture. The results will also directly serve the protection of architectural heritage in Qinghai Province, China and the ‘Silk Road (South Asia Section) Transnational Serial Application for World Heritage’ work. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
Generating the Regular Axis from Irregular Column Grids through Genetic Algorithm
Appl. Sci. 2022, 12(4), 2109; https://doi.org/10.3390/app12042109 - 17 Feb 2022
Cited by 3 | Viewed by 877
Abstract
Historic building information modeling (HBIM) provides an index frame for digital documentation of the cultural heritage, as a continuous process of reverse engineering. The index frame should be a regular model, with a clear comprehension of each component; consequently, associated knowledge could be [...] Read more.
Historic building information modeling (HBIM) provides an index frame for digital documentation of the cultural heritage, as a continuous process of reverse engineering. The index frame should be a regular model, with a clear comprehension of each component; consequently, associated knowledge could be live-updated with the investigation progress. Therefore, the method of data registration stresses its importance. The axis is fundamental for Chinese traditional architecture as the basis for positioning all components in wooden structures. However, displacement often happens. To correct the displacement while modeling, the hypothetical axis should be determined first. This paper thus proposes a method of generating the regular axis from irregular column grids and aims to develop an automatic solution that is repeatable and transplantable. The finite element modeling (FEM) abstracts the actual problem to enable numerical calculation. Starting from a candidate solution, the genetic algorithm calculates a solution closest to the expectation from the possible solutions in several minutes. The standard deviation is used to measure the amount of displacement based on the hypothetical axis, which is expected to be minimum. This method is compatible with most kinds of input data, e.g., point cloud, excel data, 2D drawing, mesh model, etc., and applied to a World Heritage Site in Qufu (Shandong, China). The results show the displacement of columns with visual expression and numerical analysis and prove that the proposed method is repeatable and traceable and can easily be applied to different projects by changing input parameters. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Case Report
Subcutaneous Emphysema Related to Dental Treatment: A Case Series
Healthcare 2022, 10(2), 290; https://doi.org/10.3390/healthcare10020290 - 01 Feb 2022
Viewed by 1061
Abstract
Cervicofacial subcutaneous emphysema (SE) is primarily caused by dental treatment introducing gas into the subcutaneous tissue. Air rapidly dissects into the subcutaneous tissue with face and neck swelling, leading to respiratory distress, patient discomfort, and chest pain. Computed tomography (CT) can detect spreading [...] Read more.
Cervicofacial subcutaneous emphysema (SE) is primarily caused by dental treatment introducing gas into the subcutaneous tissue. Air rapidly dissects into the subcutaneous tissue with face and neck swelling, leading to respiratory distress, patient discomfort, and chest pain. Computed tomography (CT) can detect spreading SE patterns. However, the true volume of SE and the degree of air changes in the body over time remain unknown. We evaluated the healing process of SE and the temporal changes in the volume of emphysema in three cases detected using our hospital’s electronic health record systems based on inclusion and exclusion criteria over the past 10 years, with CT and three-dimensional (3D) images. The first case was a 46-year-old woman who presented with complaints of swelling from her right eyelid to the neck and clavicles, pain on swallowing, respiratory distress, and hoarseness. The second case was a 35-year-old man who presented with complaints of swelling over the face. The third case was a 36-year-old man who presented with complaints of swelling from the left cheek to the neck. CT revealed SE and pneumomediastinum in all cases. All the patients were administered an antibacterial drug. The CT and 3D images showed an improvement in emphysema 3 days after the onset, with more than half of the volume reduction in emphysema. This made it possible to evaluate the changes in the air content of SE. Observation with CT until the healing process of SE is completed is crucial, and 3D images also help evaluate changes over time. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
3D Static Point Cloud Registration by Estimating Temporal Human Pose at Multiview
Sensors 2022, 22(3), 1097; https://doi.org/10.3390/s22031097 - 31 Jan 2022
Viewed by 1548
Abstract
This paper proposes a new technique for performing 3D static-point cloud registration after calibrating a multi-view RGB-D camera using a 3D (dimensional) joint set. Consistent feature points are required to calibrate a multi-view camera, and accurate feature points are necessary to obtain high-accuracy [...] Read more.
This paper proposes a new technique for performing 3D static-point cloud registration after calibrating a multi-view RGB-D camera using a 3D (dimensional) joint set. Consistent feature points are required to calibrate a multi-view camera, and accurate feature points are necessary to obtain high-accuracy calibration results. In general, a special tool, such as a chessboard, is used to calibrate a multi-view camera. However, this paper uses joints on a human skeleton as feature points for calibrating a multi-view camera to perform calibration efficiently without special tools. We propose an RGB-D-based calibration algorithm that uses the joint coordinates of the 3D joint set obtained through pose estimation as feature points. Since human body information captured by the multi-view camera may be incomplete, a joint set predicted based on image information obtained through this may be incomplete. After efficiently integrating a plurality of incomplete joint sets into one joint set, multi-view cameras can be calibrated by using the combined joint set to obtain extrinsic matrices. To increase the accuracy of calibration, multiple joint sets are used for optimization through temporal iteration. We prove through experiments that it is possible to calibrate a multi-view camera using a large number of incomplete joint sets. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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Article
Eye-Tracking in Interactive Virtual Environments: Implementation and Evaluation
Appl. Sci. 2022, 12(3), 1027; https://doi.org/10.3390/app12031027 - 19 Jan 2022
Cited by 4 | Viewed by 12470
Abstract
Not all eye-tracking methodology and data processing are equal. While the use of eye-tracking is intricate because of its grounding in visual physiology, traditional 2D eye-tracking methods are supported by software, tools, and reference studies. This is not so true for eye-tracking methods [...] Read more.
Not all eye-tracking methodology and data processing are equal. While the use of eye-tracking is intricate because of its grounding in visual physiology, traditional 2D eye-tracking methods are supported by software, tools, and reference studies. This is not so true for eye-tracking methods applied in virtual reality (imaginary 3D environments). Previous research regarded the domain of eye-tracking in 3D virtual reality as an untamed realm with unaddressed issues. The present paper explores these issues, discusses possible solutions at a theoretical level, and offers example implementations. The paper also proposes a workflow and software architecture that encompasses an entire experimental scenario, including virtual scene preparation and operationalization of visual stimuli, experimental data collection and considerations for ambiguous visual stimuli, post-hoc data correction, data aggregation, and visualization. The paper is accompanied by examples of eye-tracking data collection and evaluation based on ongoing research of indoor evacuation behavior. Full article
(This article belongs to the Topic Virtual Reality, Digital Twins, the Metaverse)
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