Maja Matijasevic

Control architectures for autonomous underwater vehicles

Autonomous underwater vehicles (AUVs) share common control problems with other air, land, and water unmanned vehicles. In addition to requiring high-dimensional and computationally intensive sensory data for real-time mission execution, power and communication limitations in an underwater environment make it more difficult to develop a control architecture for an AUV. In this article, the four types of control architectures being used for AUVs (hierarchical, heterarchical, subsumption, and hybrid architecture) are reviewed. A summary of 25 existing AUVs and a review of 11 AUV control architecture systems present a flavor of the state of the art in AUV technology. A new sensor-based embedded AUV control system architecture is also described and its implementation is discussed.

Application-Level QoS Negotiation and Signaling for Advanced Multimedia Services in the IMS

The IP multimedia subsystem (IMS) has been recognized as a reference next-generation network architecture for offering multimedia services over an Internet Protocol (IP)-based infrastructure. One of the key benefits of the IMS is efficient and flexible introduction of new services and access to third-party application providers, thanks to standard interfaces and standardized service capabilities. To support novel media-rich applications across a wide range of user devices and access networks, IMS must support negotiable quality of service (QoS) for IP multimedia sessions. In this article, we describe the application-level QoS signaling as specified by the 3GPP and propose some enhancements based on advanced QoS parameter matching and optimization functionality to be included along the signaling path. We outline various signaling flow scenarios and discuss them in the context of a case study involving an IMS-supported 3D virtual environment, featuring a treasure-hunt-like game.

Analysis of QoS requirements for e-health services and mapping to evolved packet system QoS classes

E-Health services comprise a broad range of healthcare services delivered by using information and communication technology. In order to support existing as well as emerging e-Health services over converged next generation network (NGN) architectures, there is a need for network QoS control mechanisms that meet the often stringent requirements of such services. In this paper, we evaluate the QoS support for e-Health services in the context of the Evolved Packet System (EPS), specified by the Third Generation Partnership Project (3GPP) as a multi-access all-IP NGN. We classify heterogeneous e-Health services based on context and network QoS requirements and propose a mapping to existing 3GPP QoS Class Identifiers (QCIs) that serve as a basis for the class-based QoS concept of the EPS. The proposed mapping aims to provide network operators with guidelines for meeting heterogeneous e-Health service requirements. As an example, we present the QoS requirements for a prototype e-Health service supporting tele-consultation between a patient and a doctor and illustrate the use of the proposed mapping to QCIs in standardized QoS control procedures.

MMORPG Player actions: Network performance, session patterns and latency requirements analysis

Providing Massively Multiplayer Online Role-Playing Games (MMORPGs) is a big challenge for future mobile, IP-based networks. Understanding how the players’ actions affect the network parameters, the game platform, and the overall perceived quality is highly relevant for the purposes of game design, as well as for the networking infrastructure and network support for games. We break player actions down into discrete categories, and show that each category is distinct in terms of several key metrics. We discuss which categories of actions could be supported on current mobile devices, and present evidence in form of a user survey demonstrating the demand for such services. The starting points into the discussion include the networking, session and latency requirements for particular player actions on one side, and the players’ interest on the other. The Blizzard Entertainment’s World of Warcraft (WoW) is used as a case study.

A framework for multiuser distributed virtual environments

A framework for multi-user distributed virtual environments (DVEs) has been proposed. The proposed framework, incorporating two models (the functional model and the interconnection model), attempts to represent the common functionality, communication issues and requirements found in multi-user DVEs. The functional model concentrates on the DVEs functionality, while the interconnection model concentrates on how the components are interconnected to realize the required functionality. The models have been specified using the Unified Modeling Language (UML). An experimental case study demonstrates the applicability and generality of the proposed approach.

Why MMORPG players do what they do: relating motivations to action categories

This paper presents an analysis of relations between player motivation and behaviour in a Massively Multiplayer Online Role-Playing Game (MMORPG). Player motivation is measured in terms of percentile ranks of motivational components for MMORPG players defined by Nick Yee. Player behaviour is described through previously defined action categories for MMORPGs (Trading, Questing, Dungeons, Raiding, Player versus Player Combat, and Communication). We conduct a player survey and perform measurements on the client side for a group of 104 players of World of Warcraft. Additionally we examine the importance of both voice and textual communication in MMORPGs.

MMORPG player behavior model based on player action categories

In this paper we present the modeling of player behavior for Massively Multiplayer Online Role-Playing Games (MMORPGs). We have performed action specific measurements of player sessions in terms of the previously defined action categories for MMORPGs (Trading, Questing, Dungeons, Raiding, and Player versus Player Combat). We explore the hourly trends in user behavior and form models based on observed patterns. We explore the session duration as well as lengths and probability of session segments (i.e., parts of the session consisting of only one category of player actions). Our aim is to create the user behavior model and to combine it with previously established traffic models in order to be able to explain, predict, and generate network traffic of MMORPGs more accurately. As a case study we use World of Warcraft.

DataTraffic Monitoring and Analysis: from measurement, classification, and anomaly detection to quality of experience

The Internet has opened new avenues for information accessing and sharing in a variety of media formats. Such popularity has resulted in an increase of the amount of resources consumed in backbone links, whose capacities have witnessed numerous upgrades to cope with the ever-increasing demand for bandwidth. Consequently, network traffic processing at today’s data transmission rates is a very demanding task, which has been traditionally accomplished by means of specialized hardware tailored to specific tasks. However, such approaches lack either of flexibility or extensibility—or both. As an alternative, the research community has pointed to the utilization of commodity hardware, which may provide flexible and extensible cost-aware solutions, ergo entailing large reductions of the operational and capital expenditure investments. In this chapter, we provide a survey-like introduction to high-performance network traffic processing using commodity hardware. We present the required background to understand the different solutions proposed in the literature to achieve high-speed lossless packet capture, which are reviewed and compared.High-Performance Network Traffic Processing Systems Using Commodity Hardware.- Active Techniques for Available Bandwidth Estimation: Comparison and Application.- Internet Topology Discovery.- Internet PoP Level Maps.- Analysis of Packet Transmission Processes in Peer-to-Peer Networks by Statistical Inference Methods.- Reviewing Traffic Classification.- A Methodological Overview on Anomaly Detection.- Changepoint Detection Techniques for VoIP Traffic.- Distribution-Based Anomaly Detection in Network Traffic.- From Packets to People: Quality of Experience as a New Measurement Challenge.- Internet Video Delivery in YouTube: From Traffic Measurements to Quality of Experience.- Quality Evaluation in Peer-to-Peer IPTV Services.- Cross-Layer FEC-Based Mechanism for Packet Loss Resilient Video Transmission.- Approaches for Utility-Based QoE-Driven Optimization of Network Resource Allocation for Multimedia Services.- Active Techniques for Available Bandwidth Estimation: Comparison and Application.- Internet Topology Discovery.- Internet PoP Level Maps.- Analysis of Packet Transmission Processes in Peer-to-Peer Networks by Statistical Inference Methods.- Reviewing Traffic Classification.- A Methodological Overview on Anomaly Detection.- Changepoint Detection Techniques for VoIP Traffic.- Distribution-Based Anomaly Detection in Network Traffic.- From Packets to People: Quality of Experience as a New Measurement Challenge.- Internet Video Delivery in YouTube: From Traffic Measurements to Quality of Experience.- Quality Evaluation in Peer-to-Peer IPTV Services.- Cross-Layer FEC-Based Mechanism for Packet Loss Resilient Video Transmission.- Approaches for Utility-Based QoE-Driven Optimization of Network Resource Allocation for Multimedia Services.

Action specific Massive Multiplayer Online Role Playing Games traffic analysis: case study of World of Warcraft

In Massive Multiplayer Online Role Playing Games (MMORPGs) players can perform various actions in the virtual world. We try to answer the question how is generated network traffic, and to what extent, dependent of the action that player performs and overall context/situation in the virtual world. We have divided action types in four major categories: questing, trading, raiding, and player versus player (PvP) combat. We have carried out action-specific measurements of the network traffic for the World of Warcraft (WoW) game and gathered 1.28 GB of data on which the analysis was performed. The traffic analysis included network bandwidth usage, packet payload size, percentage of data packets in the total traffic, packet rate, and packet interarrival and interdeparture times. While the category of PvP combat has highest overall demands on the client side traffic, raiding imposes highest demands on the server side. Trading showed lowest demands on the both sides in almost all categories of the analysis.

Cross-layer QoE-driven admission control and resource allocation for adaptive multimedia services in LTE

This paper proposes novel resource management mechanisms for multimedia services in 3GPP Long Term Evolution (LTE) networks aimed at enhancing session establishment success and network resources management, while maintaining acceptable end-user quality of experience (QoE) levels. We focus on two aspects, namely admission control mechanisms and resource allocation. Our cross-layer approach relies on application-level user- and service-related knowledge exchanged at session initiation time, whereby different feasible service configurations corresponding to different quality levels and resource requirements can be negotiated and passed on to network-level resource management mechanisms. We propose an admission control algorithm which admits sessions by considering multiple feasible configurations of a given service, and compare it with a baseline algorithm that considers only single service configurations, which is further related to other state-of-the-art algorithms. Our results show that admission probability can be increased in light of admitting less resource-demanding configurations in cases where resource restrictions prevent admission of a session at the highest quality level. Additionally, in case of reduced resource availability, we consider resource reallocation mechanisms based on controlled session quality degradation while maintaining user QoE above the acceptable threshold. Simulation results have shown that given a wireless access network with limited resources, our approach leads to increased session establishment success (i.e., fewer sessions are blocked) while maintaining acceptable user-perceived quality levels. Graphical abstractDisplay Omitted