World representation is a crucial aspect of any design and development effort in the field of Vir... more World representation is a crucial aspect of any design and development effort in the field of Virtual Environments today. Approaches presented so far don't seem to address all relevant needs. In this paper, we propose a model for the representation of physical properties, functionality and semantics of objects in virtual environments. Our proposed model aims to be uniform, pragmatic, systematic and extendible. We demonstrate practical usage of the proposed model through a complete example. Also, we briefly describe two case studies ...
CHI Greece 2021: 1st International Conference of the ACM Greek SIGCHI Chapter, 2021
Touchscreens are a widely used medium for interacting with digital applications in public and the... more Touchscreens are a widely used medium for interacting with digital applications in public and they are found in various contexts including entertainment, culture, travel, marketing, etc. However, in the current times of COVID-19 pandemic there are safety concerns about the use of these devices, as touching a common surface may increase the risk of transmission. Thus, there is a need for alternative means for interacting with public interactive kiosks in a usable and effective way. In this paper we propose and evaluate a universal solution to safer interactions with public touchscreens using the smartphone as a touchpad controller. Users have to scan a QR code, and then use their device as a controller to interact with the public system though touch and multi-touch interactions (tap, drag and two-finger gestures). We have setup a user study, where we compare the usability and user experience of smartphone control to the traditional touchscreen input and we examine the users’ intention and opinion about the proposed approach. Our study indicates that the use of the mobile device as a controller has the potential to be a safe and practical alternative to direct touch input for public interactive kiosks, and reveals some usability issues that need further consideration.
Intelligent agent systems have been the subject of intensive research over the past few years; th... more Intelligent agent systems have been the subject of intensive research over the past few years; they comprise one of the most promising computing approaches ever, able to address issues that require abstract modelling and higher level reasoning. Virtual environments, on the other hand, offer the ideal means to produce simulations of the real world for purposes of entertainment, education, and others. The merging of these two fields seems to have a lot to offer to both research and applications, if progress is made on a co-ordinated manner and towards standardization. This paper is a presentation of VITAL, an intelligent multi-agent system able to support general-purpose intelligent virtual environment applications.
Intelligent multi-agent systems are currently used for a variety of purposes, both in research an... more Intelligent multi-agent systems are currently used for a variety of purposes, both in research and for real-world applications. One of their most interesting, yet not fully explored uses, is as frameworks to support computerbased simulations of virtual worlds inhabited by life-like entities, that is, intelligent virtual environments, for purposes of education, demonstration and entertainment. This paper is a presentation of mVITAL, an intelligent multiagent system aiming to serve most of the fields such systems are today used in, while being fully capable of supporting intelligent virtual environment applications, where issues such as sophisticated virtual reality representation, advanced reasoning, as well as user embodiment, intervention and interaction, are crucial. To justify this, a fully operational example of such an application, namely, the Vital Playground, is also presented.
X3D is an open, royalty-free, scene-graph-based standard for 3D virtual worlds that has been used... more X3D is an open, royalty-free, scene-graph-based standard for 3D virtual worlds that has been used by virtual environment developers many times until today. As a virtual environment development tool, it has numerous appealing features; however, it also has certain characteristics that may, under certain circumstances, create significant problems to developers. With a motivation to communicate our own experience to, and contribute to the efforts of, other researchers who are using or consider using it, we evaluate X3D in a virtual environment developer's perspective and identify potential problems with its usage. Also, we present an architectural pattern aimed at addressing those problems effectively, with a focus on transparency, standards-compliance, reusability and extendibility. In conclusion, we present a case study of the application of the proposed pattern in a fully-implemented intelligent virtual environment system.
The definition of intelligent virtual agent behaviour is a key stage in the process of developing... more The definition of intelligent virtual agent behaviour is a key stage in the process of developing any intelligent virtual environment application. Ranging from simple scripting languages to full-featured, general-purpose programming languages, the means available to developers for defining agent behaviour are bound by the choice of development methodology and platform for the entire system. In this paper, we present a tool for programming the behaviour of intelligent virtual agents in intelligent virtual environment applications on an implementation-independent basis using the Prolog language. Our aim is to evaluate the potential of Prolog as a means for defining intelligent virtual agent behaviour as well as extend our previous work in the field.
In this paper we present DIVA, an architecture for Intelligent Virtual Environments. In DIVA, sys... more In this paper we present DIVA, an architecture for Intelligent Virtual Environments. In DIVA, systems consist of three different modules. There is a World Server that represents the environment in an abstract way, an arb itrary number of Intelligent Agent Clients acting as the world’s inhabitants and a set of Visualisation Clients that generate the system’s visual output. All client modules are autonomous and can be dynamically connected and disconnected to the World Server.
International Journal on Artificial Intelligence Tools, 2014
Intelligent virtual agent behaviour is a crucial element of any virtual environment application a... more Intelligent virtual agent behaviour is a crucial element of any virtual environment application as it essentially brings the environment to life, introduces believability and realism and enables complex interactions and evolution over time. However, the development of mechanisms for virtual agent perception and action is neither a trivial nor a straight-forward task. In this paper we present a model of perception and action for intelligent virtual agents that meets specific requirements and can as such be systematically implemented, can seamlessly and transparently integrate with knowledge representation and intelligent reasoning mechanisms, is highly independent of virtual world implementation specifics, and enables virtual agent portability and reuse.
The development of intelligent virtual environments is a demanding process due to their increased... more The development of intelligent virtual environments is a demanding process due to their increased complexity and the need for integration of diverse technologies. Substantial efforts are made to address the issue in a targeted fashion, in terms of virtual space representation, virtual object semantics and functionality, and intelligent virtual agent perception and action. However, the field lacks methodologies that address the issue uniformly and provide for reusability, maintainability and extendibility. In this paper we present an overview of our ...
2012 16th Panhellenic Conference on Informatics, 2012
Abstract Virtual environments are used today in a variety of application areas to produce virtual... more Abstract Virtual environments are used today in a variety of application areas to produce virtual worlds that are highly dynamic, not only as a result of autonomous agent behaviour but, also, due to the effects of the application of physics laws. Motivated by the inherent complexity in both virtual environment systems and physics engines, we present our efforts so far towards a methodology for the systematic and uniform integration of physics engines with virtual environments by discussing the integration of the Vesper3D physics engine ...
Proceedings of the 4th Helenic Conference on Advances in Artificial Intelligence, 2006
Abstract. As the field of Intelligent Virtual Agents evolves and advances, an ever increasing num... more Abstract. As the field of Intelligent Virtual Agents evolves and advances, an ever increasing number of functional and useful applications are presented. Intelligent Virtual Agents have become more realistic, intelligent and sociable, with apparent and substantial benefits to domains such as training, tutoring, simulation and entertainment. However, even though many end-users can enjoy these benefits today, the development of such applications is restricted to specialized research groups and companies. Obvious and difficult-to- ...
International Journal of Computational Intelligence Studies, Mar 20, 2015
ABSTRACT Any autonomous agent behaviour generation mechanism should incorporate as a core module,... more ABSTRACT Any autonomous agent behaviour generation mechanism should incorporate as a core module, a source of internal motivation that functions as a start point for agent behaviour to commence. Intelligent virtual agents are typically respondent to external stimuli, however, their behaviour becomes repetitive and trivial when these stimuli are missing. We argue that it is necessary for virtual agents to be equipped with intrinsic motivations that energise and direct their behaviour, in order to function in a coherent and believable way. Adopting the general principles of hierarchical motivation theories, in the current work, we attempt to model physiological needs as the lowest and basic level of motivations, in a layered motivational architecture. Based on readings from physiology, we present the mechanisms underlying the function of four basic needs and propose a model that allows the incorporation of plausible human-like needs in an intelligent virtual agent.
World representation is a crucial aspect of any design and development effort in the field of Vir... more World representation is a crucial aspect of any design and development effort in the field of Virtual Environments today. Approaches presented so far don't seem to address all relevant needs. In this paper, we propose a model for the representation of physical properties, functionality and semantics of objects in virtual environments. Our proposed model aims to be uniform, pragmatic, systematic and extendible. We demonstrate practical usage of the proposed model through a complete example. Also, we briefly describe two case studies ...
CHI Greece 2021: 1st International Conference of the ACM Greek SIGCHI Chapter, 2021
Touchscreens are a widely used medium for interacting with digital applications in public and the... more Touchscreens are a widely used medium for interacting with digital applications in public and they are found in various contexts including entertainment, culture, travel, marketing, etc. However, in the current times of COVID-19 pandemic there are safety concerns about the use of these devices, as touching a common surface may increase the risk of transmission. Thus, there is a need for alternative means for interacting with public interactive kiosks in a usable and effective way. In this paper we propose and evaluate a universal solution to safer interactions with public touchscreens using the smartphone as a touchpad controller. Users have to scan a QR code, and then use their device as a controller to interact with the public system though touch and multi-touch interactions (tap, drag and two-finger gestures). We have setup a user study, where we compare the usability and user experience of smartphone control to the traditional touchscreen input and we examine the users’ intention and opinion about the proposed approach. Our study indicates that the use of the mobile device as a controller has the potential to be a safe and practical alternative to direct touch input for public interactive kiosks, and reveals some usability issues that need further consideration.
Intelligent agent systems have been the subject of intensive research over the past few years; th... more Intelligent agent systems have been the subject of intensive research over the past few years; they comprise one of the most promising computing approaches ever, able to address issues that require abstract modelling and higher level reasoning. Virtual environments, on the other hand, offer the ideal means to produce simulations of the real world for purposes of entertainment, education, and others. The merging of these two fields seems to have a lot to offer to both research and applications, if progress is made on a co-ordinated manner and towards standardization. This paper is a presentation of VITAL, an intelligent multi-agent system able to support general-purpose intelligent virtual environment applications.
Intelligent multi-agent systems are currently used for a variety of purposes, both in research an... more Intelligent multi-agent systems are currently used for a variety of purposes, both in research and for real-world applications. One of their most interesting, yet not fully explored uses, is as frameworks to support computerbased simulations of virtual worlds inhabited by life-like entities, that is, intelligent virtual environments, for purposes of education, demonstration and entertainment. This paper is a presentation of mVITAL, an intelligent multiagent system aiming to serve most of the fields such systems are today used in, while being fully capable of supporting intelligent virtual environment applications, where issues such as sophisticated virtual reality representation, advanced reasoning, as well as user embodiment, intervention and interaction, are crucial. To justify this, a fully operational example of such an application, namely, the Vital Playground, is also presented.
X3D is an open, royalty-free, scene-graph-based standard for 3D virtual worlds that has been used... more X3D is an open, royalty-free, scene-graph-based standard for 3D virtual worlds that has been used by virtual environment developers many times until today. As a virtual environment development tool, it has numerous appealing features; however, it also has certain characteristics that may, under certain circumstances, create significant problems to developers. With a motivation to communicate our own experience to, and contribute to the efforts of, other researchers who are using or consider using it, we evaluate X3D in a virtual environment developer's perspective and identify potential problems with its usage. Also, we present an architectural pattern aimed at addressing those problems effectively, with a focus on transparency, standards-compliance, reusability and extendibility. In conclusion, we present a case study of the application of the proposed pattern in a fully-implemented intelligent virtual environment system.
The definition of intelligent virtual agent behaviour is a key stage in the process of developing... more The definition of intelligent virtual agent behaviour is a key stage in the process of developing any intelligent virtual environment application. Ranging from simple scripting languages to full-featured, general-purpose programming languages, the means available to developers for defining agent behaviour are bound by the choice of development methodology and platform for the entire system. In this paper, we present a tool for programming the behaviour of intelligent virtual agents in intelligent virtual environment applications on an implementation-independent basis using the Prolog language. Our aim is to evaluate the potential of Prolog as a means for defining intelligent virtual agent behaviour as well as extend our previous work in the field.
In this paper we present DIVA, an architecture for Intelligent Virtual Environments. In DIVA, sys... more In this paper we present DIVA, an architecture for Intelligent Virtual Environments. In DIVA, systems consist of three different modules. There is a World Server that represents the environment in an abstract way, an arb itrary number of Intelligent Agent Clients acting as the world’s inhabitants and a set of Visualisation Clients that generate the system’s visual output. All client modules are autonomous and can be dynamically connected and disconnected to the World Server.
International Journal on Artificial Intelligence Tools, 2014
Intelligent virtual agent behaviour is a crucial element of any virtual environment application a... more Intelligent virtual agent behaviour is a crucial element of any virtual environment application as it essentially brings the environment to life, introduces believability and realism and enables complex interactions and evolution over time. However, the development of mechanisms for virtual agent perception and action is neither a trivial nor a straight-forward task. In this paper we present a model of perception and action for intelligent virtual agents that meets specific requirements and can as such be systematically implemented, can seamlessly and transparently integrate with knowledge representation and intelligent reasoning mechanisms, is highly independent of virtual world implementation specifics, and enables virtual agent portability and reuse.
The development of intelligent virtual environments is a demanding process due to their increased... more The development of intelligent virtual environments is a demanding process due to their increased complexity and the need for integration of diverse technologies. Substantial efforts are made to address the issue in a targeted fashion, in terms of virtual space representation, virtual object semantics and functionality, and intelligent virtual agent perception and action. However, the field lacks methodologies that address the issue uniformly and provide for reusability, maintainability and extendibility. In this paper we present an overview of our ...
2012 16th Panhellenic Conference on Informatics, 2012
Abstract Virtual environments are used today in a variety of application areas to produce virtual... more Abstract Virtual environments are used today in a variety of application areas to produce virtual worlds that are highly dynamic, not only as a result of autonomous agent behaviour but, also, due to the effects of the application of physics laws. Motivated by the inherent complexity in both virtual environment systems and physics engines, we present our efforts so far towards a methodology for the systematic and uniform integration of physics engines with virtual environments by discussing the integration of the Vesper3D physics engine ...
Proceedings of the 4th Helenic Conference on Advances in Artificial Intelligence, 2006
Abstract. As the field of Intelligent Virtual Agents evolves and advances, an ever increasing num... more Abstract. As the field of Intelligent Virtual Agents evolves and advances, an ever increasing number of functional and useful applications are presented. Intelligent Virtual Agents have become more realistic, intelligent and sociable, with apparent and substantial benefits to domains such as training, tutoring, simulation and entertainment. However, even though many end-users can enjoy these benefits today, the development of such applications is restricted to specialized research groups and companies. Obvious and difficult-to- ...
International Journal of Computational Intelligence Studies, Mar 20, 2015
ABSTRACT Any autonomous agent behaviour generation mechanism should incorporate as a core module,... more ABSTRACT Any autonomous agent behaviour generation mechanism should incorporate as a core module, a source of internal motivation that functions as a start point for agent behaviour to commence. Intelligent virtual agents are typically respondent to external stimuli, however, their behaviour becomes repetitive and trivial when these stimuli are missing. We argue that it is necessary for virtual agents to be equipped with intrinsic motivations that energise and direct their behaviour, in order to function in a coherent and believable way. Adopting the general principles of hierarchical motivation theories, in the current work, we attempt to model physiological needs as the lowest and basic level of motivations, in a layered motivational architecture. Based on readings from physiology, we present the mechanisms underlying the function of four basic needs and propose a model that allows the incorporation of plausible human-like needs in an intelligent virtual agent.
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Papers by George Anastassakis