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The technological advances we are witnessing today have stimulated the creation of many 3D virtual environments for various purposes, from entertainment to industry to education. While the majority of these environments are perfectly suited for the healthy population, we should not forget about impaired people living among us. Regarding children’s education, one may wonder how impaired children handle them. Do they find them usable and attractive? How well do they handle basic activities in 3D environments, including orientation and interaction with objects? The experiment presented in this article provides answers to these questions within a specific setup. The experiment used a custom web application with several 3D virtual environments in a desktop virtual reality setting. The participants were 12 children, aged 8–14, with multiple impairments, predominantly hearing impairment, borderline and mild degree of mental retardation, and inferior communication skills. The answers can be regarded as positive and are based on results gathered in the form of completion times and the System Usability Scale questionnaire scores. The article also reports on a significant relation found between completion times and questionnaire scores. Future research directions, including those related to the Metaverse concept, are discussed, too.

This paper deals with an approach to upper limbs therapy that uses virtual reality technologies. The previous methods and subsequent improvements of these procedures by means of a skeletal model of the upper limb in a virtual environment are presented here. So, main focus of the paper is on the description of calculation related to the bone rotation system within appropriate skeletal model. The therapist can add either more virtual upper limb objects or more virtual training objects to the virtual environment and thus expand/change the scene or the therapy complexity. The functions used in the limb movement calculations are useful for creating additional animations with various objects. With this system, the patient can be stimulated under the supervision of a therapist to practice certain rehabilitation procedures. Due to the use of collaborative web-based virtual reality, the therapy can be also applied in a remote form. The way in which the underlying idea of rehabilitation process is implemented and it is also described. In the conclusion are the some notes about system testing and evaluation including description of a therapist interface.

The following chapter presents an experience with academic education in computer games design and development based on game theory, emphasizing iterative development, rapid (paper) prototyping, and game testing. We demonstrate and comment on various educational activities focused on game testing, describing them in steps and including benefits and motivation. Iteration of card game rules, design of a board game, design of a computer game with a paper prototype, and testing of early-access games are supplemented with students’ practical outputs in both text and graphical form. The results include feedback in the testing forms: Focus Groups, Playtesting, Usability Testing, and Quality Assurance.

The paper deals with the measurement of individual size components of particulate matter focusing on typical particle size, mass, and number concentrations primarily in the city of Košice (Slovak republic) and the surrounding countryside. The deployment of the sensor IPS-7100 in the 2nd half of December 2022 allowed us to measure the particles smaller than the detection limit of other low-cost optical sensors—namely SPS30 and SEN54. The results show that although the mass concentration of ultrafine particles is negligible in comparison to fine and coarse particles, in terms of number concentration ultrafine particles make up the dominant component of particulate matter, which stands as a warning from the health point of view.

This work introduces a uniform smartphone controller interface integrated into LIRKIS G-CVE web-based global collaborative virtual environments. In general, VR controllers provide various kinds of interaction techniques to manipulate virtual objects. Mostly, those aim focus on controlling the virtual context and the interaction with 3D GUI integrated in the virtual environment. With respect to web-based virtual reality, the progress in development of uniform interfaces is raising thanks to emerging web technologies and frameworks with cross-platform support. Although there are many manufacturers of VR controllers, their usage is often limited only for specified display device. Our intention is to cover multiple devices through only one simple controller interface, that is capable to provide a variety of interactions for web-based VR. In this study we proposed Enhanced Smart Client Interface designed for providing fully immersive interaction through smartphones. We performed several experiments focused on user experience and usability under two cloud platforms. Results obtained from experiments performed in our study confirm that utilization of our interface is mostly affected by the server response time. Based on the results this solution is suitable for further development and improvements.

Recent advances in the field of web technologies, including the increasing support of virtual reality hardware, have allowed for shared virtual environments, reachable by just entering a URL in a browser. One contemporary solution that provides such a shared virtual reality is LIRKIS Global Collaborative Virtual Environments (LIRKIS G-CVE). It is a web-based software system, built on top of the A-Frame and Networked-Aframe frameworks. This paper describes LIRKIS G-CVE and introduces its two original components. The first one is the Smart-Client Interface, which turns smart devices, such as smartphones and tablets, into input devices. The advantage of this component over the standard way of user input is demonstrated by a series of experiments. The second component is the Enhanced Client Access layer, which provides access to positions and orientations of clients that share a virtual environment. The layer also stores a history of connected clients and provides limited control over the clients. The paper also outlines an ongoing experiment aimed at an evaluation of LIRKIS G-CVE in the area of virtual prototype testing.

Computer games and, of course, the development associated with them have been in the spotlight for many years; recently, also with technologies, such as virtual reality or extended reality. The main part of this chapter presents the classification of collaborative XR systems, the concept of the major application architectures and the consistency models of shared virtual game environments. The next subchapter briefly deals with the sharing of property ownership. The mentioned concepts and examples used in the chapter are implemented in many works and projects using a collaborative environment (also in gamified form) developed in the laboratory LIRKIS, the home laboratory of the authors. The knowledge presented in this chapter may provide tips and inspiration for some other game projects, and practical and useful notes on the advantages or disadvantages of some systems will be interesting and useful.

The article presents for the first time a gallery of 3D boundary surfaces of a multi-value memory cell. In the analysis, we chose such sizes of parasitic elements on the chip, in which there are no stable limit cycles present in the memory, assuming that the absence of stable limit cycles will greatly simplify the transcription of information in the memory. However, this fact was not confirmed and the 3D gallery of boundary surfaces points to the need to know the boundary surface for each case of changing the size of parasitic capacitances on the chip. This will make it possible to explain the memory failure associated with, for example, a change in technology in the memory production. At the same time, visualization of boundary surfaces, attractors or chaotic attractors using virtual reality technologies is offered for another technical activities.

Web-based collaborative virtual reality is emerging as platform-independent technology that permits developers to produce fully immersive and interactive virtual environments accessible through web-browsers. The use of collaborative virtual environments can be helpful in situations when therapists and patients are unable to meet personally. This work introduces an extension of the LIRKIS G-CVE system with web-based interfaces for remote management of the upper limb rehabilitation process. Concerning the quality and safety of web technologies., we consider distant virtual training to be efficient for ordinary people.

This paper describes a development of a sofware solution for disabled users on symbol (pictogram) - text interface level. The solution is extended by a gesture recognition, which works with a sign-language. A symbol (pictogram) represents an idea encapsulated into a simple drawing. Its purpose is to better understand given situation. When teaching children to read, it is required that the text used is not impersonal. The purpose of the text is not only to give information; it should also “touch” the child and provide understanding. The paper offers a description of the sofware solution implementation. It also provides selected examples of the solution utilization and its evaluation.

– Visuospatial cognitive functions play a crucial role in human cognition. In recent years., these functions have sparked interest among researchers., neuroscientists and psychologists., focusing on their training., assessment and restoration. Virtual reality (VR) provides an immersive environment., which can be used for stimulation of these cognitive functions and its effects that can be measured afterwards. The experimental procedure., described in this paper., bring us closer to understanding how a VR experience., in a gamified form using a tower defense genre game., may improve our visuospatial cognitive functions. An incremental development., described in this paper., is a shift from the use of a unique but expensive VR CAVE to a more flexible., smaller and cheaper solution – a VR headset. The development utilizes a progressive mix of web and VR technologies. The presented approach can contribute to a new method of experiment participants testing., even outside a laboratory environment.

The paper describes an alternative use of some smartphone sensors to determine the characteristics and driving style. Two applications have been designed and built. These applications enable the collection of data from the sensors of smartphones while driving and the evaluation of these measurements aimed at detecting the driver's driving style. The test measurements of various types of vehicle starting were performed and evaluated using the proposed applications. Finally, the way of using this solution after certain modifications for disabled people on wheelchairs is presented.

This paper focuses on the description of the interface design of a backend server and the design implementation of a user interface suitable for the visualization of virtual and real objects/appliances controlled in a SMART environment, for example in the home, with regard to the cognitive abilities of the user. Client applications will be able to use the REST API and communicate through this API using requests, use implemented logic, and store objects and their states in the database. The server is deployed in the cloud to be accessible outside the local network. The solution is universal and offers a generic standard to support different types of appliances using a generic form. Task scheduling is also an important function. In virtual reality, it is possible to quickly test the cognitive abilities of the user and thus adapt the user interface to his needs.

Despite their support in contemporary specifications for web-based virtual, augmented and mixed reality, such as WebXR, user interaction is limited in several ways in corresponding web applications. This paper introduces software components providing solution for two of these limitations: a lack of six degrees of freedom motion capturing for smartphone-based VR headsets and no hand gesture support for MS HoloLens. The components have been developed for LIRKIS Global - Collaborative Virtual Environments, but can be used for any web applications utilizing the A-Frame framework. The paper describes both components and evaluates their performance.

LIRKIS CAVE is a unique immersive virtual reality installation with a compact cylinder-based construction and a high-quality stereoscopic video output rendered on twenty 55” Full HD LCD panels. While the video output of the CAVE provides a high level of immersion to a virtual world, its original implementation of peripherals support had a negative impact because of a limited number of supported devices and certain performance issues. In this paper we describe a new, distributed, peripheral devices support implementation for the LIRKIS CAVE, which solves the performance issues and allows for ease of integration of new input devices into the CAVE. We also present a successful integration of a special input device, the Myo armband,which allows a natural and unobtrusive gesture-based control of virtual environments. The integration includes a newly developed control and monitoring application for the Myo, called MLCCS, which utilization is not limited to CAVE systems or virtual reality applications.

At the Department of Computers and Informatics, Faculty of Electrical Engineering and Informatics TU Kosice (DCI FEEI TU Kosice) students can study virtual reality technologies and computer graphics. This subject in education process is relatively young. The study is focused on the acquirement of theoretical knowledge and practical experiences about 3D computer graphics, virtual reality and its technologies including natural and bioadaptive user interfaces and computer games. Students work in our laboratory (LIRKIS) with the latest virtual reality technologies (e.g. augmented/mixed reality, data helmets including Microsoft Hololens, 3D scanning or 3D printing) during practical exercises and they create content for them (such as applications or virtual models and scenes). Currently we also have a new self-developed technology known as CAVE (Cave Automatic Virtual Environment). For education purposes it is also important to know what students know about virtual reality and its technologies to correctly adjust lessons to the students’ knowledge and to the needs of practice. The main focus is the usage of these technologies for handicapped people education. This paper presents our experiences in education of virtual reality in both ways: as subject of study and also as tool for studying.

In the paper we present the sound output of analogue signal from the Chua’s circuit. We are not interested only in the classic displaying of graphically interesting attractors in the plane, but we are also interested in the sound of them. Changes in Chua's circuit parameters result in a variety of periodic and chaotic attractors that can also be used in music or cryptography. MIDI keys have been used so that a signal with the appropriate tone frequency is generated for each key. The result of using various output signals of the Chua’s circuit is presented through the internationally known Slovak folk song "The furnace fell down". Also, we point out the possibilities of using chaos in rehabilitation in hearing testing.

Utilization of web-based Collaborative Virtual Environments (CVE) enhances user’s interaction over large geographical distances. Deploying a variety of VR technologies increases demands to develop VR applications which would run on various systems and devices. Otherwise, user’s access is limited by the supported operating system. Nowadays, concerning the quality and safety of web technologies, it is possible to provide Global Collaborative Virtual Environments (G-CVE) with cross-platform support. This paper introduces the LIRKIS G-CVE web-based system, built on top of the Networked-Aframe framework. The architecture of LIRKIS G-CVE is presented, together with is innovative Smart-client interface (SCI) component, which utilizes smart devices, such as smartphones and tablets, as input devices. The advantage of SCI over the standard input component of the Networked-Aframe is demonstrated via a series of experiments.

In recent years, visuospatial cognitive functions, which play a crucial role in human cognition, have sparked interest among psychologists and neuroscientists, focusing on assessment, training and restoration of these functions. Virtual reality, recognized as a modern technology, addressing the real-life aspects of visuospatial processing, provides an immersive environment that can be used for stimulation of cognitive functions and its effects that can be measured afterwards. In this paper, we describe an experimental design that involves cognitive testing and targeted, cognitively-oriented, stimulation in an immersive 3D virtual environment, rendered by a unique CAVE system. We focus primarily on a game, designed and developed to serve as the virtual environment. We also describe the experimental procedure that includes the measurement of an electrophysiological neural correlate of spatial working memory capacity – contralateral delay activity.

COVID-19-related quarantine measures resulted in a significant increase of interest in online collaboration tools. This includes virtual reality (VR) or, in more general term, extended reality (XR) solutions. Shared XR allows for activities such as presentations, training of personnel or therapy to take place in a virtual space instead of a real one. To make online XR as accessible as possible, a significant effort has been put into the development of solutions that can run directly in web browsers. One of the most recognized solutions is the A-Frame software framework, created by Mozilla VR team and supporting most of the contemporary XR hardware. In addition, an extension called Networked-Aframe allows multiple users to share virtual environments, created using A-Frame, in real time. In this article, we introduce and experimentally evaluate three components that extend the functionality of A-Frame and Networked-Aframe. The first one extends Networked-Aframe with the ability to monitor and control users in a shared virtual scene. The second one implements six degrees of freedom motion tracking for smartphone-based VR headsets. The third one brings hand gesture support to the Microsoft HoloLens holographic computer. The evaluation was performed in a dedicated local network environment with 5, 10, 15 and 20 client computers. Each computer represented one user in a shared virtual scene. Since the experiments were carried out with and without the introduced components, the results presented here can also be regarded as a performance evaluation of A-Frame and Networked-Aframe themselves.

This chapter deals with the visualization of chaotic attractors of the Chua's circuit and the so-called boundary surface that separates individual attractors from each other in the circuit. Due to unceasing activities in exploration of the new chaos-generating systems and the utilization of chaos in areas such as rehabilitation, noise generation, cryptography, synchronization, neural networks, economics, cancer research, true random number generators, or secret communication, it is necessary to know and visualize both the boundary surface morphology and the chaotic attractor. The chapter covers not only the historical perspective of visualization of chaotic attractors and boundary surfaces, but also a very graphic and modern way of visualization which is the use of virtual reality means, specifically, “virtual cave.” Due to the time-consuming calculation of the boundary surface, we also mention the possibilities of its calculation in 3D state space using parallelization. The abovementioned knowledge of calculation and visualization of the boundary surface and attractors by means of virtual reality can be used not only in Chua's system, but also in any autonomous system.

Mixed reality technologies provide more natural interaction with virtual objects integrated in physical environments. Considering global lighting conditions, the spatial mapping has limitations, which manifest when scanning under limited light intensity. This paper evaluates the impact of red, green and blue monochromatic lighting sources on the spatial map scanning and distance measurement process of the Microsoft HoloLens holographic computer and head-mounted display. The paper also compares luminous power values, measured by MS HoloLens, with the ones obtained from a professional luminous flux meter.

The paper deals with the description of the possibilities how chaos can be used for cognitive tests using virtual reality technologies. In the first part is description of relation between virtual reality, cognitive testing and chaos. N ext chapter deals about chaos and possibilities of its usage. In the final are mentioned three ways of possible chaos use in cognitive testing and also proposal of chaos implementation into environment of virtual CAVE is here. This is main idea for better result obtaining for cognitive testing in this case.

Thanks to the recent advancement in computer hardware and software, the virtual reality is becoming a hot topic, again. It can be utilized in various settings - from entertainment through education and workforce training to a training and assessment of visuospatial cognitive functions. A fully immersive virtual reality experience requires not only high quality stereoscopic graphical output but also input devices that feel natural to use. In this paper we present two cost-effective solutions that try to fulfil this requirement: a low-cost modular walking pad and an application for an Android device, which utilizes the gyroscope of the device to manipulate with objects in a virtual environment. While both solutions have been primarily developed to be used with cave automatic virtual environments, they are also suitable for installations utilizing see-through head-mounted displays or ordinary computer screens.

Virtual reality systems create interaction between users and virtual environment. Gesture recognition has wide applicability in various industries. There are several types of I/O control devices to achieve quality between user and system interaction. Current hand-held and armband devices enhance immersion and interaction between user and virtual environment. Cognitive trainings in Virtual reality have positive effect to measure user interaction and responsiveness. In fact, there are different technologies and ways to recognize gestures for controlling Virtual environments. It can be helpful to work more naturally and intuitively with hand gesture in the future.

Visuospatial functions play a crucial role in human cognition, which has elicited over years a great deal of research focusing on their assessment, training and restoration. Interestingly, although our visuospatial capacities allow us to understand and infer relationships of 3D objects in space, these 3D aspects of visuospatial processing are profoundly neglected in laboratory tests, and instead, 2D designs are commonly used. Aiming to increase the ecological validity of such tests, we propose an experiment to evaluate the capacity of a 3D virtual space to stimulate cognitive functions. The experiment involves cognitive testing, EEG measurements, and cognitively stimulating tasks in an immersive 3D virtual environment rendered by a unique CAVE system. This paper focuses primarily on two game prototypes that will serve as the virtual environment and describes a natural movement control using the Myo armband, incorporated into one of the games. We also briefly discuss cognitive testing design using the selected brain electrophysiological variables measured on human subjects before and after the virtual reality game use, in order to assess the potential effect of the game.

This paper deals with particular issues in detection of human body’s movement using contactless sensor and consecutive application of recorded data on avatars model.We aimed at applying transformations to the skeleton model and skin of the avatar. Initial stages include choice of proper sensor and appropriate methods for transformation description. A semi-immersive virtual reality training system in the form of a fitting room has been chosen as a particular implementation of the body movement detection and application. The fitting room was selected because of its entertaining nature and a potential to be used as a training system for handicapped people with movement impairments.

The paper presents the parallelization of calculations of cut through the boundary surface of the Chua circuit. The calculation itself implies a high demands for the computer processor and it is therefore referred to the technique of using parallelization in this case. We also point to the undisputed advantage of parallelization the boundary surface calculation. It is not only a much faster calculation on the new Intel i7 7700 processor, but also electric energy saving. Faster results also imply a better applicability of this circuit.

LIRKIS CAVE, designed and built at the home institution of the authors, is an immersive virtual reality environment of unique, cylinder based construction with stereoscopic video output provided by twenty 55” 3D LCD displays. While the visualization engine of the CAVE is optimized for the unusual display arrangement, motion tracking and 3D mouse input, it originally lacked in support of other input devices. In this paper we deal with the problem of extending and optimizing the peripheral devices support by introducing a socket-based approach, which connects an external input processing application directly to a distributed virtual scene rendering application.

Information technologies impact our daily life in many significant ways. Nevertheless, there is a lack of availability of some technologies to the wide public caused by their location and price. This insufficiency seems to be even bigger for disabled people. LIRKIS laboratory of Technical university of Kosice proposes solutions in education of these people and develops technologies of virtual reality which are capable to fulfill their needs. This paper is aimed at user interfaces (as VR technology) and the smart environment from human-centered perspective. The development process could become time consuming because in many cases the electrical network, sensory network and other physical elements need to be rebuilt to begin another test. Virtual reality technologies could solve this kind of issues low cost and fast. In this work a CAVE system was used in the comparison of standard approaches.

The paper presents LIRKIS CAVE, a Cave Automatic Virtual Environment, developed and built at the home institution of authors. The most significant features of LIRKIS CAVE are a compact and transportable design and use of LCD displays, organized in a decagon. The CAVE is described in terms of hardware and software and its performance is evaluated by a series of experiments. The paper also outlines future research and development activities related to the CAVE, which focus on the area of rehabilitation and education of handicapped people.

This paper introduces a method for performing parallel computations of the boundary surface of Chua's circuit. The presented approach could be characterized as a SIMD method which is based on the utilization of all available CPU cores. Performance comparisons between single and parallelized calculations on different computer systems are included in a table at the end of the article. The best results were observed using the highest compiler optimisation options on 64 bit architecture and using Intel i7 CPUs.

Computer games became an inseparable part of everyday life in modern society and the time people spend playing them every day is increasing. This trend caused a noticeable research activity focused on utilizing the time spent playing in a meaningful way, for example to help solving scientific problems or tasks related to computer systems development. In this paper we present one contribution to this activity, a software system consisting of a modified version of the Open Rails train simulator and an application called TS2JavaConn, which allows to use separately developed software controllers with the simulator. The system is intended for validation of controllers developed by formal methods. The paper describes the overall architecture of the system and operation of its components. It also compares the system with other approaches to purposeful utilization of computer games, specifies suitable formal methods and illustrates its intended use on an example.

Information technologies impact our daily life in many significant ways. Despite this there is a lack of availability of some technologies to the wide public caused by their availability and price. This insufficiency seems to be even bigger for handicapped people. LIRKIS laboratory of Technical university of Kosice proposes solutions in education of these people and develops technologies of virtual reality which are capable to fulfill their needs. One such VR technology is a unique CAVE system, which is also available in the LIRKIS laboratory and gives a new dimension for further educational opportunities. The paper describes the technologies and original designs available at LIRKIS and their relation to the handicapped people education.

The paper deals with an issue of a design, development and implementation of a fully immersive virtual reality (VR) system and corresponding virtual worlds, specified in an object-oriented fashion. A virtual world object structure, reflecting a division of VR system into subsystems with respect to affected senses, is introduced. It also discusses virtual worlds building process, utilizing the software development technique of stepwise refinement, and possibilities of parallel processing in VR systems. The final part describes a VR system that has been implemented at the home institution of the authors according to some of the ideas presented here.

Subject of this article is visualization ofchaotic attractor in 3D space. 3D view of chaosenables create a demonstrative projection aboutrelations of chaos generated by physical circuit -Chua’s circuit. The program created in C++program language enables view on chaotic attractorboth in 2D and 3D space together with plane objectsvisualization – elements of singularities. The Chua’sattractor visualisation represents visualization oflarge graphical data set.

This paper deals with computer graphics, human body detection and application of computer graphics in avatar control. The main goal of this work is to design and create virtual training system including avatar using contactless sensors. Authors focus on the control of the humanoid avatar by applying transformations to his skeleton. To achieve this, proper sensor is chosen. Avatar is able to perform movements that can be reproducible by script generated data during training. Developed system implements all requirements of virtual fitting room in the scope of case study. This system can be used for better understanding of some moving problems of handicapped people.

Part 11: Social Impact of EIS and Visualization; International audience; The aim of the paper is to present the advantages of the Use Cases transformation to the object layers and their visualization in 3D space to reduce complexity. Our work moves selected UML diagram from two-dimensional to multidimensional space for better visualization and readability of the structure or behaviour.Our general scope is to exploit layers for particular components or modules, time and author versions, particular object types (GUI, Business services, DB services, abstract domain classes, role and scenario classes), patterns and anti-patterns in the structure, aspects in the particular layers for solving crosscutting concerns and anti-patterns, alternative and parallel scenarios, pessimistic, optimistic and daily use scenarios.We successfully apply force directed algorithm to create more convenient automated class diagrams layout. In addition to this algorithm, we introduced semantics by adding weight factor in force calculation process.

The aim of this article consists in description of visualization of chaotic attractor and elements of the singularities in 3D space. 3D view of these effects enables create a demonstrative projection about relations of chaos generated by physical circuit — Chua's circuit. The created program enables a view on chaotic attractor in 3D space together with plane objects visualization — elements of singularities and boundary surface. The visualization of Chua's attractor, elements of the singularities and boundary surface represents visualization of large graphical data set.

The aim of this work is to highlight the use of semi-immersive virtual reality in educational process. Part of the effort is explanation of virtual reality systems considering immersion and human-computer interaction. For implementation of such a system was needed to define requirements to enhance productivity during education. Described solution is based on virtual workbench using touch user interface and disposes with capabilities to lead a student through infinite amount of use-cases. Important property is evaluation of student's steps.