With the rapid development in the areas of mobile manufacturing and multimedia communications, there is an increasing demand for Networked Virtual Environment (NVE) applications, such as Augmented Reality (AR), virtual walk-throughs, and massively multiplayer online games (MMOGs), on hand-held devices. Unfortunately, downloading and rendering a complex 3D scene is very computationally intensive and is not compatible with current mobile hardware specifications nor with available wireless bandwidth. Existing NVE applications deploy client/server based 3D streaming over thin mobile devices, which suffer from single point of failure, latency, and scalability issues. To address these issues, image-based rendering (IBR) and cloud-based 3D streaming have been introduced. The former introduces visual artifacts that reduce, and usually cancel, the realistic behaviors of the Virtual Environment (VE) application, while the latter is considered very expensive to implement. Peer-to-peer (P2P) 3D streaming is promising and affordable, but it has to tackle issues in object discovery and selection as well as content provider strategies. Distributing VE content over a mobile ad-hoc network (MANET) makes the system difficult to update due to the dynamic nature of the mobile clients. In order to tackle these issues, we came up with a novel protocol that combines the pros of both central and distributed approaches. Our proposed hybrid protocol, called OCTET, enables 3D scene streaming over thin devices in a way that can cope with current mobile hardware capabilities and mitigate the challenges of client/server and P2P 3D streaming. In fact, OCTET provides strategies that select, prioritize, and deliver only those objects that contribute to the user’s visible scene. OCTET is implemented using the "ns-2" simulation environment, and extensive experiments have clearly demonstrated significant achievements in mobile resource utilization, throughput, and system scalability.

Researchers have been studying virtual world culture for decades. However, little attention has been devoted to the intersection of virtual world culture and real world culture. Even less attention has been given to the study of comparing players' different virtual world game behaviors that have been influenced by their own real world cultural background. In this paper, I specifically focus on identifying the differences among American, Chinese, and Taiwanese cultures and the unique aspects of players with distinct cultural backgrounds that alter the atmosphere of the game. This is a mixed-method ﾓtrans ludicﾔ? study across three game servers that included participant observation, interviews, and surveys. The result of this study show that real world culture influences virtual world culture. Players in different countries bring real life experiences to the game and form their own emergent sub-cultures and sub-rules under the larger structure of the designated game rules and social conventions. When players immigrate from their original server to other countries' servers, initially they tend to find people from the same country to play with and follow their old social conventions, which are the sub-rules they create in their old servers, rather than play with the local players and adapt to new customs. However, over time, players develop hybrid cultures that adopt features from both the old cultures. This study also demonstrates that emergent behaviors are likely to occur when players face problems or difficult challenges.

With the rapid development in the areas of mobile manufacturing and multimedia communications, there is an increasing demand for Networked Virtual Environment (NVE) applications, such as Augmented Reality (AR), virtual walk-throughs, and massively multiplayer online games (MMOGs), on hand-held devices. Unfortunately, downloading and rendering a complex 3D scene is very computationally intensive and is not compatible with current mobile hardware specifications nor with available wireless bandwidth. Existing NVE applications deploy client/server based 3D streaming over thin mobile devices, which suffer from single point of failure, latency, and scalability issues. To address these issues, image-based rendering (IBR) and cloud-based 3D streaming have been introduced. The former introduces visual artifacts that reduce, and usually cancel, the realistic behaviors of the Virtual Environment (VE) application, while the latter is considered very expensive to implement. Peer-to-peer (P2P) 3D streaming is promising and affordable, but it has to tackle issues in object discovery and selection as well as content provider strategies. Distributing VE content over a mobile ad-hoc network (MANET) makes the system difficult to update due to the dynamic nature of the mobile clients. In order to tackle these issues, we came up with a novel protocol that combines the pros of both central and distributed approaches. Our proposed hybrid protocol, called OCTET, enables 3D scene streaming over thin devices in a way that can cope with current mobile hardware capabilities and mitigate the challenges of client/server and P2P 3D streaming. In fact, OCTET provides strategies that select, prioritize, and deliver only those objects that contribute to the user’s visible scene. OCTET is implemented using the "ns-2" simulation environment, and extensive experiments have clearly demonstrated significant achievements in mobile resource utilization, throughput, and system scalability.

With the rapid development in the areas of mobile manufacturing and multimedia communications, there is an increasing demand for Networked Virtual Environment (NVE) applications, such as Augmented Reality (AR), virtual walk-throughs, and massively multiplayer online games (MMOGs), on hand-held devices. Unfortunately, downloading and rendering a complex 3D scene is very computationally intensive and is not compatible with current mobile hardware specifications nor with available wireless bandwidth. Existing NVE applications deploy client/server based 3D streaming over thin mobile devices, which suffer from single point of failure, latency, and scalability issues. To address these issues, image-based rendering (IBR) and cloud-based 3D streaming have been introduced. The former introduces visual artifacts that reduce, and usually cancel, the realistic behaviors of the Virtual Environment (VE) application, while the latter is considered very expensive to implement. Peer-to-peer (P2P) 3D streaming is promising and affordable, but it has to tackle issues in object discovery and selection as well as content provider strategies. Distributing VE content over a mobile ad-hoc network (MANET) makes the system difficult to update due to the dynamic nature of the mobile clients. In order to tackle these issues, we came up with a novel protocol that combines the pros of both central and distributed approaches. Our proposed hybrid protocol, called OCTET, enables 3D scene streaming over thin devices in a way that can cope with current mobile hardware capabilities and mitigate the challenges of client/server and P2P 3D streaming. In fact, OCTET provides strategies that select, prioritize, and deliver only those objects that contribute to the user’s visible scene. OCTET is implemented using the "ns-2" simulation environment, and extensive experiments have clearly demonstrated significant achievements in mobile resource utilization, throughput, and system scalability.

Current Massively Multi-player Online Games (MMOGs) have enormous server-side bandwidth requirements. The costs of providing this bandwidth is in turn passed on to the consumer in the form of high monthly subscription fees. Prior work has primarily focused on distributing this bandwidth using peer-to-peer architectures, but these architectures have difficulty preventing cheating, overwhelming low resource peers, and maintaining consistent game state. We have developed a hybrid game architecture that combines client-server and peer-to-peer technologies to prevent cheating, maintain centralized and consistent game state, significantly reduce central server bandwidth, and prevent lower capacity players from being overwhelmed. By dramatically reducing the bandwidth needed to host a game without introducing additional liabilities, our hybrid architecture reduces the costs associated with that bandwidth and allows MMOG developers to reduce the cost of monthly subscription fees. In addition, because the central server will need less bandwidth per player, a single server is able to support considerably more concurrent players. Our experiments show that bandwidth can be reduced by up to 95% and a single server can support a game twice as large.

This is a thesis that deals with the norms and rules of players playing online games together. It is also a thesis about believability, the current capabilities of non-player characters (NPCs) and the attitudes amongst game developers towards dynamic and systemic games AI. The primary theme of this thesis considers which means of communication and coordination in terms of norms and rules are present in groups of players and particularly in guilds and clans playing Massively Multi Online Games (MMOGs) and First Person Shooters (FPSs) respectively. The presence of norms in these types of groups has been overlooked in previous research even though guilds have been addressed to some extent. When rules have been discussed in games research, the actual use, meaning and interpretation behind these rules from a player perspective has been omitted. In this thesis rules and norms are interpreted from a guild and clan perspective as important means for coordination, used in order to keep the group together. The implicit rules are further seen as implicit rules made explicit through guild and clan forums where these groups of players express how to preserve the shared game experience. The absence of rituals, norms and rules has also been studied in temporary groups of one MMOG, with the explanation that existing relations with other players are maintained in these game sessions, but new relations are usually seen as too costly to invest in. The second theme is directed at believability and the state of current NPCs, how immersion is influenced by NPCs that do not act in believable ways. The second theme is also influenced by the first theme, whereby rules and norms are seen as valuable tools for creating believability in NPCs, directly targeting the social layer, a slightly overlooked area of research. The last section is directed at applying the results from the first section, how players play by the rules and norms of the group, and how this could foster believability in NPCs. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: In press. Paper 5: In press. Paper 6: In press.</p>

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Recently, there has been significant research focus on Peer-to-Peer (P2P) Massively Multi-user Virtual Environments (MMVEs). A number of architectures have been presented in the literature to implement the P2P approach. One aspect that has not received sufficient attention in these architectures is state management and state persistency in P2P MMVEs. This work presents and simulates a novel state management and persistency architecture, called Pithos. In order to design the architecture, an investigation is performed into state consistency architectures, into which the state management and persistency architecture should fit. A novel generic state consistency model is proposed that encapsulated all state consistency models reviewed. The requirements for state management and persistency architectures, identified during the review of state consistency models, are used to review state management and persistency architectures currently receiving research attention. Identifying some deficiencies present in current designs, such as lack of fairness, responsiveness and scalability, a novel state management and persistency architecture, called Pithos, is designed. Pithos is a reliable, responsive, secure, fair and scalable distributed storage system, ideally suited to P2P MMVEs. Pithos is implemented in Oversim, which runs on the Omnet++ network simulator. An evaluation of Pithos is performed to verify that it satisfies the identified requirements. It is found that the reliability of Pithos depends heavily on object lifetimes. If an object lives longer on average, retrieval requests are more reliable. An investigation is performed into the factors influencing object lifetime. A novel Markov chain model is proposed which allows for the prediction of objects lifetimes in any finite sized network, for a given amount of redundancy, node lifetime characteristics and object repair rate. / AFRIKAANSE OPSOMMING: Onlangs is daar ’n beduidende navorsingsfokus op Eweknie Massiewe Multi-gebruiker Virtuele Omgewings (MMVOs). ’n Aantal argitekture is in die literatuur beskikbaar wat die eweknie benadering voorstel. Een aspek wat nie voldoende aandag ontvang in hierdie argitekture nie is toestandsbestuur en toestandsvolharding in eweknie MMVOs. Hierdie werk ontwerp en simuleer ’n nuwe toestandsbestuur- en toestandsvolhardingargitektuur genaamd Pithos. Ten einde die argitektuur te ontwerp is ’n ondersoek uitgevoer in toestandskonsekwentheidargitekture, waarin die toestandsbestuur- en toestandsvolhardingargitektuur moet pas. ’n Nuwe generiese toestandskonsekwentheidargitektuur word voorgestel wat alle hersiene toestandskonsekwentheid argitekture vervat. Die vereistes vir die toestandsbestuur- en toestandsvolhardingargitekture, geidentifiseer tydens die hersiening van die toestandskonsekwentheidargitekture, word gebruik om toestandsbestuuren toestandsvolhardingargitekture te hersien wat tans navorsingsaandag geniet. Identifisering van sekere leemtes teenwoordig in die huidige ontwerpe, soos ’n gebrek aan regverdigheid, responsiwiteit en skaleerbaarheid, lei tot die ontwerp van ’n nuwe toestandsbestuur- en toestandsvolhardingargitektuur wat Pithos genoem word. Pithos is ’n betroubare, responsiewe, veilige, regverdige en skaleerbare verspreide stoorstelsel, ideaal geskik is vir eweknie MMVOs. Pithos word geïmplementeer in Oversim, wat loop op die Omnet++ netwerk simulator. ’n Evaluering van Pithos word uitgevoer om te verifieer dat dit voldoen aan die geïdentifiseerde behoeftes. Daar is gevind dat die betroubaarheid van Pithos afhang van die objek leeftyd. As ’n objek gemiddeld langer leef, dan is herwinning versoeke meer betroubaar. ’n Ondersoek word uitgevoer na die faktore wat die objek leeftyd beïnvloed. ’n Nuwe Markov ketting model word voorgestel wat voorsiening maak vir die voorspelling van objek leeftye in eindige grootte netwerke, vir gegewe hoeveelhede van oortolligheid, nodus leeftyd eienskappe en objek herstelkoers.

This research considers how the culture of game developer Cyan Worlds influences the gameplay environment and the culture of fans in Myst Online: Uru Live. The game has gone through two commercial releases and in both cases it was cancelled after a short time. Fans have attempted to salvage the game by producing their own server software and content creation tools. Recently, Cyan released their own source code and development tools to the fan community, giving fans an official channel for creating new content. This work builds off of Pearce's (2009b) study of the culture of Uru players and emergent play, but adds the dimension of considering the culture of developers themselves. A primary goal of this study was to determine how the culture of a game developer like Cyan shapes the constraints of the designed "play ecosystem" (Pearce 2009b: 7), and how it shapes the processes by which fans can salvage aspects of the game to create new content. One finding is that the design of Uru's gameplay environment is rooted in the cultural practices, personal philosophical goals and individual personality traits of its developers. Fans were able to assert ownership over the Uru story-world and the means of production of new content by proactively applying technical and problem-solving skills--the same sorts of skills that players must apply to solving puzzles in Myst games. This fan action, coupled with Cyan's goal of making an open-ended world, has helped to propel the initiative to provide open-source tools for creating new content. When fans produce new content, they draw significantly from an existing shared cultural repertoire of cues and conventions. These conventions are supported both by the software affordances of the development environment and by cultural precedent--they are readily adapted to Myst-like narratives and are easily "read" by experienced players.