The main purpose of this special issue is to examine simulation/gaming as a trans-disciplinary field of inquiry and practice from the perspective of the science of design. The principle of indeterminacy applied to the social and human realm stipulates that the only way we can know human reality is by engaging it. Gaming represents a particularly powerful approach to engage people in shaping learning communities and in enhancing communities of practice. Principles and methods for designing gaming/simulations as such are well documented in the literature. In the 1970s and 1980s the communities of gamers have paid special attention to the methods and techniques of game design and model building. For example the proceedings of the annual international conferences of the International Simulation And Gaming Association (ISAGA) of 1979 focuses on “How to build a simulation/game” (Bruin, K. et al. 1979). It is out of the scope of this special issue to discuss in detail the specifications of simulation/game design or to assess particular design methods. Focus is on the ramifications of simulation/game design and its impact on the broader social context of use. Simulation/game design does not happen in a social vacuum. It is part of a common understanding of associations such as ISAGA, NASAGA, SAGSET, ABSEL, JASAG, and SAGSAGA, which propagate proper design and use of simulation games, the debriefing included. It is also embedded in the practice on how to involve the user or client system in the design process. Moreover, gamers aim at influencing social practice by improving the competencies of individual actors and social agents involved.
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The Mobile IPv6 (MIPv6) provides many great features, such as sufficient addressing space, mobility, and security; MIPv6 is one of the most important protocols for next generation mobile Internet. Simultaneously, with the rapid improvement of wireless technologies, the real-time multi-media IP services such as video on demand, videoconference, interactive games, IP telephony and video IP phone will be delivered in the near future. Thus, to furnish accurate QoS for real-time services is one of the most important thing in the next generation mobile Internet. Although RSVP, which is a resource reservation protocol, processes signaling messages to establish QoS paths between senders and receivers, RSVP was originally designed for stationary networks and not aware of the mobility of MNs. Therefore, this paper proposes a novel RSVP extension to support real-time services in Hierarchical Mobile IPv6 (HMIPv6) environments. For intra-site mobility, the concept of QoS Agent (QA) is proposed to handle the RSVP QoS update messages and provide the advanced reservation models for real-time services. For inter-site mobility, IP multicast can help to invite inter-site QAs to make pre-reservation and minimize the service disruption caused by re-routing the data path during handover. Simulation results show that the proposed scheme over HMIPv6 is more suitable for real-time services than the famous RSVP tunnel-based solution. Read more...

Streaming real-time multimedia content over the Internet is gaining momentum in the communications, entertainment, music and interactive game industries as well as in the military. In general, streaming applications include IP telephony, multimedia broadcasts and various interactive applications such as multi-party conferences, collaborations and multiplayer games. Successfully realizing such applications in a highly mobile environment, however, presents many research challenges. In order to investigate such challenges and demonstrate viable solutions, we have developed an experimental indoor and outdoor testbed laboratory. By implementing standard IETF protocols into this testbed, we have demonstrated the basic functionalities required of the mobile wireless Internet to successfully support mobile multimedia access. These requirements include signaling, registration, dynamic configuration, mobility binding, location management, Authentication Authorization and Accounting (AAA), and quality of service over a variety of radio access network (RAN) technologies (e.g. 802.11b, CDMA/GPRS). In this paper, we describe this testbed and discuss important design issues and tradeoffs. We detail the incorporation and inter-relation of a wide catalog of IETF protocols-such as SIP, SAP, SDP, RTP/RTCP/RTSP, MGCP, variants of Mobile-IP, DRCP, HMMP, PANA, and DSNP-to achieve our goals. We believe that the results and experiences obtained from this experimental testbed will advance the understanding of the pertinent deployment issues for a Mobile Wireless Internet. Read more...