No. 3 (2011)
Published:
2011-09-30
ARTICLES FROM THIS ISSUE
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The IP QoS System
Abstract
This paper shortly describes the IP QoS System which offers strict quality of service (QoS) guarantees in IP-based networks and supports a number of, so called, classes of services. Such solution requires to implement in the network a set of QoS mechanisms and algorithm working on packet, connection request and provisioning levels. Furthermore, we require signaling system for informing the network about new connection request and network resource allocation capabilities for providing required resources to given connection. The IP QoS System is based on the next generation networks (NGN) and differentiated services (DiffServ) architectures and, at least for now, it is designed for single domain only.
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Performance Evaluation of Signaling in the IP QoS System
Abstract
The IP QoS System is based on next generation networks (NGN) and differentiated services (DiffServ) architectures. Its main part is a signaling system, which allows to send a request from a user to the system for establishing new connection with predefined quality of service assurance. In this paper we present trial results of the proposed signalling system. The experiments were performed to measure setup delay utilizing artificial call generator/analyzer. To obtain results we assumed different distributions of interarrival and call holding times based on the literature. The results show that the setup delay strongly depends on access time to network devices, however also on the assumed call holding time models.
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On Dimensioning and Routing in the IP QoS System
Abstract
This article presents dimensioning and routing solutions in IP QoS System designed during the implementation of the PBZ project: “Next Generation Services and Net-works – technical, application and market aspects: Traffic management – IP QoS System”. The paper presents the functional architecture together to the description of the functions and methods implemented in the system.
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QoS Conditions for VoIP and VoD
Abstract
This paper concerns quality evaluation of the telecommunication services: VoIP (representing the RT interactive class) and VoD (representing the MM streaming class). Subjective and objective methods and tools for perceived quality measurement are analyzed and compared. Subjective tests are performed for selected video sequences using the Double-Stimulus Impairment Scale (DSIS) method. Thus the objective algorithms (VQM and VQmon) are calibrated. Speech quality is measured using the objective methods: PESQ and POLQA. Threshold values for network parameters (packet loss rate, delay jitter) are set, that guarantee the acceptable service quality.
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A Software Platform for Research on Auction Mechanisms
Abstract
The platform for research on auction mechanisms is a distributed simulation framework providing means to carry out research on resource allocation efficiency mechanisms and user strategies. Both kinds of algorithms examined are completely user-defined. Interaction of algorithms is recorded and pre-defined measures for the final resource allocation are calculated. Underlying database design provides for efficient results lookup and comparison across different experiments, thus enabling research groupwork. A recognised, open and flexible information model is employed for experiment descriptions.
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The Realization of NGN Architecture for ASON/GMPLS Network
Abstract
For the last decades huge efforts of telecommunication, Internet and media organizations have been focusing on creating standards and implementing one common network delivering multimedia services – Next Generation Network. One of the technologies which are very likely to be used in NGN transport layer is ASON/GMPLS optical network. The implementation of ASON/GMPLS technology using open source software and its results are the subject of this paper. The ASON/GMPLS architecture and its relation to the proposed ITU-T NGN architecture are described. The concept, functional structure and communication among architecture elements as well as the implementation of laboratory testbed are presented. The results of functional tests confirming proper software and testbed operation are stated.
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Multi Queue Approach for Network Services Implemented for Multi Core CPUs
Abstract
Multiple core processors have already became the dominant design for general purpose CPUs. Incarnations of this technology are present in solutions dedicated to such areas like computer graphics, signal processing and also computer networking. Since the key functionality of network core components is fast package servicing, multicore technology, due to multi tasking ability, seems useful to support packet processing. Dedicated network processors characterize very good performance but at the same time high cost. General purpose CPUs achieve incredible performance, thanks to task distribution along several available cores and relatively low cost. The idea, analyzed in this paper, is to use general purpose CPU to provide network core functionality. For this purpose parameterized system model has been created, which represents general core networking needs. This model analyze system parameters influence on system performance.
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Active – Passive: On Preconceptions of Testing
Abstract
In telecommunications and software engineering, testing is normally understood to be essentially active: a tester is said to stimulate, control, and enforce. Passive testing does not fit this paradigm and thus remains the niche research subject, which bears on the scope and depth of the obtained results. It is argued that such limited understanding of testing is one of its many community-bound preconceptions. It may be acceptable in the current engineering approach to testing, but can and should be challenged in order to converge on the core concepts of the proposed science of testing (“testology”). This methodological work aims at establishing that there are no fundamental reasons for admitting the dominant role of the active element in testing. To show this, external (also extratechnical) areas are consulted for insight, direct observations, and metaphors. The troublesome distinction between (passive) testing and monitoring, as well as unclear relations between testing and measurements, are also addressed.
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Optimization of Call Admission Control for UTRAN
Abstract
This paper addresses the traffic’s grade of service indicators: call blocking and dropping rates as well as the optimization of their mutual relation, corresponding to the call admission control procedure configuration. In the presented results of simulations authors showed opportunities for the CAC load threshold adaptation according to the traffic volume and user mobility changes observed in the mobile radio network.
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Network-on-Multi-Chip (NoMC) with Monitoring and Debugging Support
Abstract
This paper summarizes recent research on network-on-multi-chip (NoMC) at Poznań University of Technology. The proposed network architecture supports hierarchical addressing and multicast transition mode. Such an approach provides new debugging functionality hardly attainable in classical hardware testing methodology. A multicast
transmission also enables real-time packet monitoring. The introduced features of NoC network allow to elaborate a model of hardware video codec that utilizes distributed processing on many FPGAs. Final performance of the designed network was assessed using a model of AVC coder and multi-FPGA platforms. In such a system, the introduced multicast transmission mode yields overall gain of bandwidth up to 30%. Moreover, synthesis results show that the basic network components designed in Verilog language are suitable and easily synthesizable for FPGA devices. -
The Design of an Objective Metric and Construction of a Prototype System for Monitoring Perceived Quality (QoE) of Video Sequences
Abstract
The paper presents different no reference (NR) objective metrics addressing the most important artefacts for raw (source) video sequences (noise, blur, exposure) and those
introduced by compression (blocking, flickering) which can be used for assessing quality of experience. The validity of all metrics was verified under subjective tests. -
Communication Platform for Evaluation of Transmitted Speech Quality
Abstract
A voice communication system designed and implemented is described. The purpose of the presented platform was to enable a series of experiments related to the quality assessment of algorithms used in the coding and transmitting of speech. The system is equipped with tools for recording signals at each stage of processing, making it possible to subject them to subjective assessments by listening tests or, ob- jective evaluation employing PESQ or PSQM algorithms. The functionality for the simulation of distortions typical for voice communication over the Internet was implemented, making it possible to obtain reproducible, quantifiable results. An application of the presented platform for evaluation of acoustic echo canceler algorithm based on watermarking techniques, which was developed earlier is presented as an example of an effective deployment of the described technology.
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Video Streaming Framework
Abstract
The framework for testing video streaming techniques is presented in this paper. Short review of error resilience and concealments tools available for the H.264/AVC
standard is given. The video streaming protocols and the H.264 payload format are also described. The experimental results obtained with the framework are presented in this paper too. -
The Learning System by the Least Squares Support Vector Machine Method and its Application in Medicine
Abstract
In the paper it has been presented the possibility of using the least squares support vector machine to the initial diagnosis of patients. In order to find some optimal parameters making the work of the algorithm more detailed, the following techniques have been used: K-fold Cross Validation, Grid-Search, Particle Swarm Optimization. The result of the classification has been checked by some labels assigned by an expert. The created system has been tested on the artificially made data and the data taken from the real database. The results of the computer simulations have been presented in two forms: numerical and graphic. All the algorithms have been implemented in the C# language.
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Designing Auctions: A Historical Perspective
Abstract
Auction is a form of organization of competition that leads to the assignment and valuation of resources based on the information obtained from the competing agents. From the perspective of systems science it is a distributed resource allocation algorithm applied in the environment with information asymmetry, i.e., where the interconnected and interacting subsystems have different information about the system as a whole. This paper presents an overview of the historical development of mathematical theory underlying modern approach to auction design. Selected practical applications of the theory are also discussed.
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Personalized Knowledge Mining in Large Text Sets
Abstract
The paper starts with a discussion of the concept of knowledge engineering, in particular ontological engineering. Consequently, the paper presents assumptions accepted as a basis for a group research on a radically personalized system of ontological knowledge mining, relying on the perspective of human centered computing and combining ontological concepts of the user with an ontology resulting from an automatic classification of a given set of textual data. The paper presents a pilot system PrOnto that supports research work in two aspects: searching for information interesting for a user according to her/his personalized ontological profile, and supporting research cooperation in a group of users (Virtual Research Community) according, e.g., to a comparison of such personalized ontological profiles. The paper concludes with suggestions concerning diverse applications of ontological engineering tools and future work.
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New SEAMCAT Propagation Models: Irregular Terrain Model and ITU-R P. 1546-4
Abstract
Implementation of the ITU-R P.1546-4 and ITM propagation models for SEAMCAT prepared and developed in the National Institute of Telecommunications Poland is presented. Results of our research encompasses methodology, implementation and verification of plug-ins into the SEAMCAT software are shown.
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Technical Aspects Outline for the Strategy of Launching Digital Broadcasting in Poland on Wave Bands Below 30 MHz
Abstract
The article discusses the state of art knowledge concerning the introduction of DRM in the world and prospects for its further development. It presents the possibility of introducing this system in Poland.
