Slawomir Przylucki

Resource Management in Grid Systems

The management of resources in the grid networks becomes complex task. The reason for this is that grids are heterogeneous, distributed and owned by different organizations environments. Each solution has own policies of resource management and different cost models. This paper contains a discussion of the issues related to resource management in grid systems on the basis of XtreemOS grid. The purpose of this study is the analysis of cost model of network management in distributed environments. The results of performed tests demonstrate how the Resource Management System (RMS) behaves under different operating conditions.

Efficiency of IP Packets Pre-marking for H264 Video Quality Guarantees in Streaming Applications

For the last few years, many classifications and marking strategies have been proposed with the consideration of video streaming applications. According to IETF recommendation, two groups of solutions have been proposed. The firts one assumes that applications or IP end points pre-mark their packets. The second solution applies the router which is topologically closest to video source. It should perform Multifield Classification and mark all incomming packets. This paper investigates the most popular marking strategies belonging to both mentioned above groups of solutions. The pre-marking strategies based on H264 coder extensions are simulated based on NS-2 network simulator and Evalvid-RA framework. The results are compared with the IETF recommendations for video traffic shaping in the IP networks and marking algorithms proposed by other researchers.

Path Loss Model for a Wireless Sensor Network in Different Weather Conditions

The paper presents path loss model for a WSN in an open space on the basis of measurements. The measurements were performed in different weather conditions i.e. temperature and humidity in agricultural area. Theoretical path loss models are always flawed because of their exponential relationship. This causes an increase in error during the localization process. Thus, the determination of the path loss exponent constant based on measurement results become so important. The study focused on designation of the path loss model for different weather conditions. The influence of the temperature and the humidity on the RSSI distribution was analysed.

RSSI-Based Localisation of the Radio Waves Source by Mobile Agents

The paper presents a practical realisation of the localisation of a radio wave source. The system is based on the RSSI principle and uses a set of blind mobile agents. The main goal of the research was to implement the localisation system of the root node in WSN on the low-cost autonomous mobile embedded platform. This platform has a limited ability for complex mathematical operations, therefore more easy algorithms should be used. The study focused on implementation of movement algorithms and exchanging the knowledge between blind agents. In the solution described the gradient search path algorithm was implemented.

QoE-Oriented Fairness Control for DASH Systems Based on the Hierarchical Structure of SVC Streams

Nowadays, multimedia content is the basis of most popular network services. At the same time, adaptive video streaming is becoming more widely used method for delivering such content to end users. The main purpose of the mechanisms of adaptation is to maximize the usage of network resources while ensuring the best quality of transmitted video. The implementation of adaptation, however, has a serious drawback of not considering the mutual influence of simultaneous transmission of multiple video streams. In this article, we propose a method of the QoE-oriented fairness control for DASH systems which uses a new utility function. This function based on a hierarchical structure of a SVC video stream. The properties of this solution were evaluated in a test environment that uses SDN principles. Functional features of the proposed control method were compared with standard algorithm of the adaptation used by DASH supported devices.

Gradation of Video Quality in Dash Services Using the H.264/SVC Coding

Abstract The share of video streaming services in the global network traffic is increasing every year. For this reason the problem of optimal use of the available bandwidth, while ensuring an acceptable level of quality of the transmitted video is becoming an important issue. A combination of two techniques, DASH streaming and H.264/AVC video coding can be an important step towards solving this problem. The article presents the discussion the choice of the proper gradation of SVC encoding parameters inside representation of video content in DASH systems. We propose the Temporal Preservation (T-P) method of selection of the SVC stream structure to optimize the grading changes of video quality. This method allows for the implementation of DASH adaptation to changes in available bandwidth on the transmission link, which minimizes the impact of this process on the quality of the received video. According to results of conducted tests, the T-P method offers a better final video quality in DASH systems than similar solutions based on a standard adaptation method. The comparison with the DASH system that uses H.264/AVC encoding also showed superiority of the T-P method, especially in situations of high network congestion

Coloring VBR Streams Inside the DiffServ Domain

Video traffic is supposed to account for a large portion of future wired and wireless network traffic. The evaluation of different video coding standards for their effects on the network traffic, and the resulting requirements for networks have attracted great interest in the research community. Simultaneously, the numerous test and users’ experiences proved that the limited quality of service (QoS) features available in both IPV4 and IPv6 cannot accommodate the various degrees of requirements needed by multimedia traffic and in particular, the video traffic. This paper investigates the influence of various packet markers on VBR video streams inside the DiffServ domain. Simulations based on NS-2 network simulator and Evalvid-RA framework and follow the IETF recommendations for video traffic shaping in the IP networks.

Evaluation of the Jammers Performance in the WiFi Band

The paper presents evaluation of the performance of two different jammers in an open space on the basis of measurements. The measurements were performed with the use of Fluke AirMagnet Spectrum XT analyser in agricultural area. Signal power heat maps were prepared and analysed. Theoretical path loss models of different jammers’ configurations were worked out. The determination of the path loss models parameters allow to calculate the theoretical heat maps and compare them with measurements. The study focused on designation of the performance of the jammers in open space. This allows to estimate the area of effective signal jamming. The influence of channel frequency in WiFi 2.4 GHz band on the jammer performance was analysed.

Software Defined Home Network for Distribution of the SVC Video Based on the DASH Principles

With the spread of Dynamic Adaptive Streaming over HTTP (DASH) systems, appeared the problem related to the resources management in end-users’ networks. The article proposes a new solution for the distribution of Scalable Video Coding (SVC) video streams in home networks. It relies on a Software Defined Network (SDN) controller, which based on the parameters of transmitted SVC video and the usage status of network resources allows for dynamic traffic shaping. At the same time, it was assumed that the proposed solution is compatible with Server and Network Assisted DASH (SAND) standard and its implementation is possible without the use of additional, dedicated hardware. The article presents the analysis of influence of proposed SDN on the improvement of the SVC video quality received by DASH clients in a typical home network. Test results confirm the superiority of the proposed system over the conventional solutions.

System of Distance Measurement and Localization of Wireless Devices Communicating Based on Bluetooth Technologies

Personal wireless networks are very popular nowadays. Wireless networks administrators have access to a great deal of information about users. They may use selected information in order to try to locate a devices who is active in a network. A mechanism has been implemented which enables the user to locate devices communicating based on bluetooth technologies, using coordinates or references to characteristic points.