Title Participants Abstract "Efficient representation, transmission and rendering of networked virtual environments on both desktop and mobile systems" "Tom JEHAES" "Over the last decade, Networked Virtual Environment (NVE) applications have greatly increased in popularity. The rst examples of these NVEs were mainly focussed on creating a virtual community in which users can navigate, communicate and interact. In recent years, however, gaming related features such as those found in role-playing games, racing games or rst person shooters have found their way into the world of networked virtual environments. Additionally, new technologies have been presented which have enabled the size of these virtual environments to grow exponentially resulting in massive online virtual communities or games. Related to the ever increasing size of virtual environments, huge amounts of data are often needed for representing their visual appearance. Contrary to earlier systems, where all the data could be stored locally, these new systems therefore need to resort to deploying large storage capacity servers from which users can request environment data at runtime. Ideally, transferring this data to the client needs to be done incrementally so the client can quickly provide an initial view of the environment. During application runtime, the environment data is continuously updated based on visibility calculations. In this work we will be targeting these large-scale dynamic networked virtual communities where application data needs to be requested at runtime. The main problem with these kinds of applications is the often disturbing scene buildup artefacts. The main research topic will therefore be focussed on reducing this scene buildup time while at the same time providing a high level of image quality coupled to a satisfactory user experience on both desktop and mobile systems. The research contributions presented in this thesis focus on three areas: data representation and streaming, objective Level-of-Detail selection and rendering on mobile devices. Firstly, we present a novel combined usage of imagebased and geometrical representations in dynamic networked virtual environments. Our first goal is to present the user with a su ciently realistic view of the virtual world as soon as possible while reducing disturbing scene buildup artifacts as well as guarantee interactive frame rates. We create image-based representations that are more compact to send than geometrical models so the client will sooner be able to render a more satisfactory view than if we would only be using incrementally transmitted models. The image-based models are also used in combination with traditional LoD techniques to speedup rendering while maintaining good display quality, which is our second goal. Run-time measurements of both client processing and network usage show the bene ts of using our system. Secondly, with regard to objective Level-of-Detail selection, the problem of rendering large virtual 3D environments at interactive framerates has traditionally been solved by using polygonal LoD selection techniques, which rely on a combination of metrics such as distance, projection size and importance. Our work on hybrid based data representations has shown that image-based techniques can be used to represent complex models in a compact way, thereby also decreasing the time needed for rendering. One of the questions that should be given some more consideration, however, is when to switch from polygonal rendering to image-based rendering in order to achieve a target framerate. We explore this topic further and provide a solution using an objective image quality metric which optimizes render quality. Several measurements, such as resulting framerate and image quality, are presented to show the bene t of our solution. Lastly, in order to allow users to access a large-scale online virtual environment at any time or place, some form of mobile access is needed using for instance a PDA or SmartPhone. We describe our approach for 3D rendering of a large virtual environment on PDA devices and discuss the main issues encountered. More speci cally, we use the results of our data representation and LoD selection research in order to limit the memory requirements and processing power needed. Furthermore, we investigate an alternative rendering scenario in which the client's view is created on a remote render server. We investigate the bene ts and drawbacks of this approach compared to the local rendering scenario." "Large-scale Networked Virtual Environments - Architecture and Applications" "Wim LAMOTTE, Peter QUAX, Eddy FLERACKERS" "Purpose – Scalability is an important research topic in the context of networked virtual environments (NVEs). This paper aims to describe the ALVIC (Architecture for Large-scale Virtual Interactive Communities) approach to NVE scalability. Design/methodology/approach – The setup and results from two case studies are shown: a 3-D learning environment through which long-term sick children can stay in close contact with their school environment; and a 3-D mobile city guide, in which city inhabitants and visitors can form a virtual community in which they share information and communicate with each other. Findings – These case studies clearly demonstrate the applicability of the ALVIC architecture. In order to be able to create even larger NVEs, a next-generation client-server NVE architecture is proposed: ALVIC-NG, which employs proxy servers and logic servers in order to balance the server load. Research limitations/implications: Further scalability tests need to be performed to evaluate this new architecture. ALVI-NG will also be the basis for a new case study, in which large 3-D city datasets will be used. Originality/Value: The results provide insight in scalability issues to those who need to deploy very large-scale networked virtual environments." "Dynamic Interactions for Networked Virtual Environments" "Pieter JORISSEN" "The field of networked virtual environments has been an active area of research in the past decades. The increasing power of contemporary computers and the lowering of hardware and connectivity costs permits people to have this technology available in their homes and workplaces. As a result, several applications and prototypes are successfully being used in several fields. Most of the research and developments have, however, been technology driven and as a result one of the main components, interaction, is much less explored. In this dissertation we focus on realizing more realistic virtual experiences by narrowing the gap between real-life and virtual world interaction possibilities. In contrast to ad hoc approaches, we also seek to provide a more general and reusable solution. The interactive object approach provides such a solution by employing a general purpose interaction mechanism for every kind of interaction in the virtual world. This mechanism relies heavily on a feature modeling approach that allows objects to describe their own interaction possibilities.As a result, the interactions become application independent and objects unknown to the application can be inserted at run time. The problem of realistic interactions is, however, not limited to representation and execution of interactions. It requires the consideration of several related fields, such as realistic simulation and animation, user embodiment and human computer interaction as well. Therefore, in a second phase, we developed and integrated the ExtReAM library into the interaction framework. This platform-independent library allows us to improve realism by enabling physical simulation and more dynamic animations for objects and user embodiments. Furthermore, it allows objects to contain physical properties and actions as well. By combining realistic simulation with our dynamic interaction mechanism, much more lively virtual worlds can be achieved with minimal effort, which can result in better virtual experiences and higher levels of presence if used properly. As more natural interaction techniques can increase the user’s feeling of being immersed in the virtual world, we analyze how our dynamic interaction and animation system can be utilized to create more realistic user embodiment control and interaction techniques. Therefore, we propose two new 3D interaction techniques, utilizing our framework. The first technique allows the user to interact directly in the virtual world by controlling his virtual hand with a 3D input device. We elaborate on how this was established and how this technique can be distributed among the participants with as little bandwidth consumption as possible. The second technique involves a travel technique that provides the user with haptic feedback on what is happening to his virtual counterpart. This was realized by converting rigid body simulation information into force feedback. By means of a formal usability study, we show how this haptic travel method results in an increased feeling of immersion." "Conveying Emotions through Facially Animated Avatars in Networked Virtual Environments" "Fabian DI FIORE, Peter QUAX, Cedric VANAKEN, Wim LAMOTTE, Frank VAN REETH" "In this paper, our objective is to facilitate the way in which emotion is conveyed through avatars in virtual environments. The established way of achieving this includes the end-user having to manually select his/her emotional state through a text base interface (using emoticons and/or keywords) and applying these pre-defined emotional states on avatars. In contrast to this rather trivial solution, we envisage a system that enables automatic extraction of emotion-related metadata from a video stream, most often originating from a webcam. Contrary to the seemingly trivial solution of sending entire video streams --- which is an optimal solution but often prohibitive in terms of bandwidth usage --- this metadata extraction process enables the system to be deployed in large-scale environments, as the bandwidth required for the communication channel is severely limited." "Efficient distribution of emotion-related data through a networked virtual environment architecture" "Peter QUAX, Fabian DI FIORE, Wim LAMOTTE, Frank VAN REETH" "In this paper we describe the way in which emotion-related data can efficiently be exchanged between participants in a large-scale networked virtual environment. This type of metadata is extracted from real-time captured video streams using off-the-shelf webcams and applied onto a two-dimensional (2D) stylised avatar; thereby improving the immersion the user experiences while navigating and communicating in the virtual world. As emotion-related data-once processed through the system-can be considered a specific type of state information, a generic networked virtual environment architecture can be used to distribute the information between participants. We have opted to extend the in-house developed architecture for large-scale virtual interactive communities (ALVIC-NG) architecture to be able to process the information flows. We Will show that the inclusion of this new type of information does not have a detrimental effect on the scalability of the system. Copyright (C) 2009 John Wiley & Sons, Ltd." "Large-scale networked virtual environments: architecture and applications" "Wim LAMOTTE, Peter QUAX, Eddy FLERACKERS" "Abstract: Purpose – Scalability is an important research topic in the context of networked virtual environments (NVEs). This paper aims to describe the ALVIC (Architecture for Large-scale Virtual Interactive Communities) approach to NVE scalability. Design/methodology/approach – The setup and results from two case studies are shown: a 3-D learning environment through which long-term sick children can stay in close contact with their school environment; and a 3-D mobile city guide, in which city inhabitants and visitors can form a virtual community in which they share information and communicate with each other. Findings – These case studies clearly demonstrate the applicability of the ALVIC architecture. In order to be able to create even larger NVEs, a next-generation client-server NVE architecture is proposed: ALVIC-NG, which employs proxy servers and logic servers in order to balance the server load. Research limitations/implications – Further scalability tests need to be performed to evaluate this new architecture. ALVIC-NG will also be the basis for a new case study, in which large 3-D city datasets will be used. Originality/value – The results provide insight in scalability issues to those who need to deploy very large-scale networked virtual environments." "ALVIC vs the Internet : Redesigning a Networked Virtual Environment Architecture" "Peter QUAX, Jeroen DIERCKX, Bart CORNELISSEN, Wim LAMOTTE" "The explosive growth of the number of applications based on networked virtual environment technology, both games and virtual communities, shows that these types of applications have become commonplace in a short period of time. However, from a research point of view, the inherent weaknesses in their architectures are quickly exposed. The Architecture for Large-Scale Virtual Interactive Communities (ALVICs) was originally developed to serve as a generic framework to deploy networked virtual environment applications on the Internet. While it has been shown to effectively scale to the numbers originally put forward, our findings have shown that, on a real-life network, such as the Internet, several drawbacks will not be overcome in the near future. It is, therefore, that we have recently started with the development of ALVIC-NG, which, while incorporating the findings from our previous research, makes several improvements on the original version, making it suitable for deployment on the Internet as it exists today." "Detecting inconsistencies in the design of virtual environments over the web using domain specific rules" "Haithem Mansouri, Frederic Kleinermann" "Nowadays, 3D Virtual Environments (VEs) are being used on the Web for various purposes such as education, collaborative working and social networking. Despite the availability of a number of Virtual Reality (VR) authoring tools, the development process of such environments remains a demanding task, often accessible only to VE experts. On the other hand, VE experts are seldom domain experts, which means that their knowledge on specific domains could be limited. This could lead to design errors or, as in most cases, longer development times and efforts as the development process become an iterative one involving many revisions. One way of accelerating this process is by making it possible to capture specific knowledge of a domain and later use this knowledge to automatically check the design of the VE against this knowledge. This way, we ensure the conformity of the VE to the domain knowledge for which it is being developed. As a result, development times and efforts can significantly be shortened, while reducing the likelihood of error making. This paper describes an extension to an existing approach called VR-WISE that focuses on reducing development times and efforts of VEs using domain oriented terminology and ontologies." "Autonomic microcell assignment in massively distributed online virtual environments" "Bruno Van Den Bossche, Bart De Vleeschauwer, Tom Verdickt, Filip De Turck, Bart Dhoedt, Piet Demeester" "Designing an MOOC as an agent-platform aggregating heterogeneous virtual learning environments" "Yves Wautelet, Stephan Poelmans" "With the emergence of cloud technologies, on the one hand, and social networks, on the other hand, the possibilities for e-learning have been drastically enhanced in the latest years. Virtual Learning Environments (VLE) can now indeed contain a huge amount of learning resources; in parallel, large user communities are available in social networks. These nevertheless remain different systems but, by using these heterogeneous software environments together, the possibilities for interaction could be multiplied. That is why, this paper suggests to build a Massive Open Online Course (MOOC) environment through a Multi-Agent System (MAS) working as a virtual abstraction layer over heterogeneous software platforms. The idea is to aggregate different traditional VLE to dispose of the learning objects they own as well as other platforms such as social networks to furnish an easy access to the MOOC of their large user communities. The MAS design has been architectured around a real-life organisational pattern – the joint venture – allowing one to deal with the complexity of heterogeneous software environments in a manner that real-life companies set up joint governance. Communication scenarios issued of a field analysis are pointed out in the paper; these are supported by the MOOC platform in the native environment as well as in Facebook. The proposal is indeed validated through the development of a prototype using Facebook as a case study for third-party platform interfacing. We finally highlight the benefits for the user experience."