41 research outputs found
A Reusable Component for Communication and Data Synchronization in Mobile Distributed Interactive Applications
In Distributed Interactive Applications (DIA) such as multiplayer games,
where many participants are involved in a same game session and communicate
through a network, they may have an inconsistent view of the virtual world
because of the communication delays across the network. This issue becomes even
more challenging when communicating through a cellular network while executing
the DIA client on a mobile terminal. Consistency maintenance algorithms may be
used to obtain a uniform view of the virtual world. These algorithms are very
complex and hard to program and therefore, the implementation and the future
evolution of the application logic code become difficult. To solve this
problem, we propose an approach where the consistency concerns are handled
separately by a distributed component called a Synchronization Medium, which is
responsible for the communication management as well as the consistency
maintenance. We present the detailed architecture of the Synchronization Medium
and the generic interfaces it offers to DIAs. We evaluate our approach both
qualitatively and quantitatively. We first demonstrate that the Synchronization
Medium is a reusable component through the development of two game
applications, a car racing game and a space war game. A performance evaluation
then shows that the overhead introduced by the Synchronization Medium remains
acceptable.Comment: In Proceedings WCSI 2010, arXiv:1010.233
Re-engineering jake2 to work on a grid using the GridGain Middleware
With the advent of Massively Multiplayer Online Games (MMOGs), engineers and
designers of games came across with many questions that needed to be answered such
as, for example, "how to allow a large amount of clients to play simultaneously on the
same server?", "how to guarantee a good quality of service (QoS) to a great number
of clients?", "how many resources will be necessary?", "how to optimize these resources
to the maximum?". A possible answer to these questions relies on the usage of grid
computing.
Taking into account the parallel and distributed nature of grid computing, we can say
that grid computing allows for more scalability in terms of a growing number of players,
guarantees shorter communication time between clients and servers, and allows for a
better resource management and usage (e.g., memory, CPU, core balancing usage, etc.)
than the traditional serial computing model.
However, the main focus of this thesis is not about grid computing. Instead, this
thesis describes the re-engineering process of an existing multiplayer computer game,
called Jake2, by transforming it into a MMOG, which is then put to run on a grid
Analyzing the effect of tcp and server population on massively multiplayer games
Many Massively Multiplayer Online Role-Playing Games (MMORPGs) use TCP flows for communication between the server and the game clients. The utilization of TCP, which was not initially designed for (soft) real-time services, has many implications for the competing traffic flows. In this paper we present a series of studies which explore the competition between MMORPG and other traffic flows. For that aim, we first extend a source-based traffic model, based on player’s activities during the day, to also incorporate the impact of the number of players sharing a server (server population) on network traffic. Based on real traffic traces, we statistically model the influence of the variation of the server’s player population on the network traffic, depending on the action categories (i.e., types of in-game player behaviour). Using the developed traffic model we prove that while server population only modifies specific action categories, this effect is significant enough to be observed on the overall traffic. We find that TCP Vegas is a good option for competing flows in order not to throttle the MMORPG flows and that TCP SACK is more respectful with game flows than other TCP variants, namely, Tahoe, Reno, and New Reno. Other tests show that MMORPG flows do not significantly reduce their sending window size when competing against UDP flows. Additionally, we study the effect of RTT unfairness between MMORPG flows, showing that it is less important than in the case of network-limited TCP flows
Dead Reckoning Using Play Patterns in a Simple 2D Multiplayer Online Game
In today’s gaming world, a player expects the same play experience whether playing on a local network or online with many geographically distant players on congested networks. Because of delay and loss, there may be discrepancies in the simulated environment from player to player, likely resulting in incorrect perception of events. It is desirable to develop methods that minimize this problem. Dead reckoning is one such method. Traditional dead reckoning schemes typically predict a player’s position linearly by assuming players move with constant force or velocity. In this paper, we consider team-based 2D online action games. In such games, player movement is rarely linear. Consequently, we implemented such a game to act as a test harness we used to collect a large amount of data from playing sessions involving a large number of experienced players. From analyzing this data, we identified play patterns, which we used to create three dead reckoning algorithms. We then used an extensive set of simulations to compare our algorithms with the IEEE standard dead reckoning algorithm and with the recent “Interest Scheme” algorithm. Our results are promising especially with respect to the average export error and the number of hits
Analyzing the Effect of TCP and Server Population on Massively Multiplayer Games
Many Massively Multiplayer Online Role-Playing Games (MMORPGs) use TCP flows for communication between the server and the game clients. The utilization of TCP, which was not initially designed for (soft) real-time services, has many implications for the competing traffic flows. In this paper we present a series of studies which explore the competition between MMORPG and other traffic flows. For that aim, we first extend a source-based traffic model, based on player’s activities during the day, to also incorporate the impact of the number of players sharing a server (server population) on network traffic. Based on real traffic traces, we statistically model the influence of the variation of the server’s player population on the network traffic, depending on the action categories (i.e., types of in-game player behaviour). Using the developed traffic model we prove that while server population only modifies specific action categories, this effect is significant enough to be observed on the overall traffic. We find that TCP Vegas is a good option for competing flows in order not to throttle the MMORPG flows and that TCP SACK is more respectful with game flows than other TCP variants, namely, Tahoe, Reno, and New Reno. Other tests show that MMORPG flows do not significantly reduce their sending window size when competing against UDP flows. Additionally, we study the effect of RTT unfairness between MMORPG flows, showing that it is less important than in the case of network-limited TCP flows
Metacognition and Self-Scaffolding in MMORPGs: Case Study of an Adolescent Male Gamer
The genre of massively multiplayer online role-playing games has become increasingly popular with adolescent males. While researchers have studied the social aspect of online role-playing games, there is little known about the metacognitive and self-scaffolding processes that players engage in as they navigate these digital immersive environments. This case study focuses on the experience of an adolescent male gamer as he develops his knowledge, selfawareness and virtual identity
ILP Modeling of Many-to-Many Replicated Multimedia Communication, Journal of Telecommunications and Information Technology, 2013, nr 3
On-line communication services were evolving from a simple text-based chats towards sophisticated videopresence appliances. The bandwidth consumption of those services is constantly growing due to the technology development and high user and business needs. That fact leads us to implement optimization mechanisms into the multimedia communication scenarios. In this paper, the authors concentrate on many-to-many (m2m) communication, that is mainly driven by the growing popularity of on-line conferences and telepresence applications. An overlay model where m2m flows are optimally established on top of a given set of network routes is formulated and a joint model where the network routes and the m2m flows are jointly optimized. In the models, the traffic traverses through replica servers, that are responsible for stream aggregation and compression. Models for both predefined replica locations and optimized server settlement are presented. Each model is being followed by a comprehensive description and is based on real teleconference systems
Solving key design issues for massively multiplayer online games on peer-to-peer architectures
Massively Multiplayer Online Games (MMOGs) are increasing in both popularity and
scale on the Internet and are predominantly implemented by Client/Server architectures.
While such a classical approach to distributed system design offers many benefits, it suffers
from significant technical and commercial drawbacks, primarily reliability and scalability
costs. This realisation has sparked recent research interest in adapting MMOGs
to Peer-to-Peer (P2P) architectures.
This thesis identifies six key design issues to be addressed by P2P MMOGs, namely
interest management, event dissemination, task sharing, state persistency, cheating mitigation,
and incentive mechanisms. Design alternatives for each issue are systematically
compared, and their interrelationships discussed. How well representative P2P MMOG
architectures fulfil the design criteria is also evaluated. It is argued that although P2P
MMOG architectures are developing rapidly, their support for task sharing and incentive
mechanisms still need to be improved.
The design of a novel framework for P2P MMOGs, Mediator, is presented. It employs a
self-organising super-peer network over a P2P overlay infrastructure, and addresses the
six design issues in an integrated system. The Mediator framework is extensible, as it
supports flexible policy plug-ins and can accommodate the introduction of new superpeer
roles. Key components of this framework have been implemented and evaluated
with a simulated P2P MMOG.
As the Mediator framework relies on super-peers for computational and administrative
tasks, membership management is crucial, e.g. to allow the system to recover from
super-peer failures. A new technology for this, namely Membership-Aware Multicast
with Bushiness Optimisation (MAMBO), has been designed, implemented and evaluated.
It reuses the communication structure of a tree-based application-level multicast
to track group membership efficiently. Evaluation of a demonstration application shows
i
that MAMBO is able to quickly detect and handle peers joining and leaving. Compared
to a conventional supervision architecture, MAMBO is more scalable, and yet incurs
less communication overheads. Besides MMOGs, MAMBO is suitable for other P2P
applications, such as collaborative computing and multimedia streaming.
This thesis also presents the design, implementation and evaluation of a novel task
mapping infrastructure for heterogeneous P2P environments, Deadline-Driven Auctions
(DDA). DDA is primarily designed to support NPC host allocation in P2P MMOGs, and
specifically in the Mediator framework. However, it can also support the sharing of computational
and interactive tasks with various deadlines in general P2P applications. Experimental
and analytical results demonstrate that DDA efficiently allocates computing
resources for large numbers of real-time NPC tasks in a simulated P2P MMOG with approximately
1000 players. Furthermore, DDA supports gaming interactivity by keeping
the communication latency among NPC hosts and ordinary players low. It also supports
flexible matchmaking policies, and can motivate application participants to contribute
resources to the system
Encouraging organized active game play in primary school children
A mobile video game designed to encourage physical activity in children in an organized outdoor setting is presented. Game elements of narrative based treasure hunt game: Pirate Adventure are designed by a team of IT and Health professionals to encourage primary school aged children to engage in physical activity. The mobile phone platform uses several sensor technologies; accelerometers, camera and Wi-Fi to integrate gameplay with the physical environment. Key game locations in the real world environment are tracked using 2-dimensional codes (QR codes) and activity is tracked using accelerometers. The design is evaluated during several organized play session. Telemetry collected demonstrates that the treasure hunt mechanic encourages players to be physically active during each game, and validates that player actions are consistent with the game design elements. QR code scanning is effective as a location tracking mechanism. Additional insight is provided into the issue of sensor suitability and mobile device reliability when used in games for this age group. The results of this study can inform other mobile active games for children