Lukas Sevcik

Network Performance QoS Prediction

This paper deals with QoS prediction of triple play services in IP networks. Based on our proposed model, speech or video quality can be calculated with regard to policies applied for packet processing by routers and to the level of total network utilization. This new simulating model was implemented in SW tool which enables networkers to predict objective QoS parameters of triple play services and to help them in network design. The contribution of this paper lies in designing a new model capable of predicting the quality of Triple-play services in networks based on IP.

Impact of H.265 and VP9 compression standards on the video quality for 4K resolution

This article deals with the impact of H.265/HEVC and VP9 compression standards on the video quality for 4K resolution. In the first part a short characteristic of both compression standards is written. The second part focuses on the well-known objective metrics which were used for evaluating the video quality. In the third part the measurements and the experimental results are described.

PFPM: Discovering Periodic Frequent Patterns with Novel Periodicity Measures

Periodic pattern mining is the task of discovering patterns that periodically appear in transactions. Typically, periodic pattern mining algorithms will discard a pattern as being nonperiodic if it has a single period greater than a maximal periodicity threshold, defined by the user. A major drawback of this approach is that it is not flexible, as a pattern can be discarded based on only one of its periods. In this chapter, we present a solution to this issue by proposing to discover periodic patterns using three measures: the minimum periodicity, the maximum periodicity, and the average periodicity. The combination of these measures has the advantage of being more flexible. Properties of these measures are studied. Moreover, an efficient algorithm named PFPM (Periodic Frequent Pattern Miner) is proposed to discover all frequent periodic patterns using these measures. An experimental evaluation on real data sets shows that the proposed PFPM algorithm is efficient and can filter a huge number of nonperiodic patterns to reveal only the desired periodic patterns.

QoE prediction model for multimedia services in IP network applying queuing policy

This paper proposes a QoE (Quality of Experience) assessment model which can estimate voice and video quality. Based on the proposed model, speech or video quality is calculated with regard to policies applied for packet processing by routers and to the level of total network utilization. The contribution of this paper lies in designing a new computational model capable of predicting the quality of multimedia services respecting queuing policy and transmission speed of interfaces on routers in IP networks.

Vulnerabilities in GSM technology and feasibility of selected attacks

Global System for Mobile communication (GSM) is the most widespread technology for mobile communications in the world and serving over 7 billion users. Since first publication of system documentation there has been notified a potential safety problem’s occurrence. Selected types of attacks, based on the analysis of the technical feasibility and the degree of risk of these weaknesses, were implemented and demonstrated in laboratory of the VSB-Technical University of Ostrava, Czech Republic. These vulnerabilities were analyzed and afterwards possible attacks were described. These attacks were implemented using open-source tools, software programmable radio USRP (Universal Software RadioPeripheral) and DVB-T (Digital Video Broadcasting – Terrestrial) receiver. GSM security architecture is being scrutinized since first public releases of its specification mainly pointing out weaknesses in authentication and ciphering mechanisms. This contribution also summarizes practically proofed and used scenarios that are performed using opensource software tools and variety of scripts mostly written in Python. Main goal of this paper is in analyzing security issues in GSM network and practical demonstration of selected attacks.

Prediction model of triple play services for QoS assessment in IP based networks

This paper brings a QoS (Quality of Service) assessment model which can estimate voice and video quality. Based on the proposed model, speech or video quality is computed with regard to congestion management QoS configuration in the network and its level of total utilization. The contribution of this paper lies in designing a new mathematical model capable of predicting the quality of multimedia services respecting network behavior and performance.

QoS of Triple Play Services in LTE Networks

This paper deals with studying the effects of performance LTE network throughput for data traffic. Utilisation rate of networks has a significant impact on the quality parameters of triple play services. LTE network was simulated by the software module additionally implemented in a development environment MATLAB. Throughput model has been obtained using this simulation that was used to test the QoS parameters for voice/video. Voice and video data streams using different codecs are transmitted for the obtained throughput. The measured qualitatively QoS parameters determine the resulting quality services from the perspective of end user perception.

Design of Emotion Recognition System

The chapter deals with a speech emotion recognition system as a complex solution including a Czech speech database of emotion samples in a form of short sound records and the tool evaluating database samples by using subjective methods. The chapter also involves individual components of an emotion recognition system and shortly describes their functions. In order to create the database of emotion samples for learning and training of emotional classifier, it was necessary to extract short sound recordings from radio and TV broadcastings. In the second step, all records in emotion database were evaluated using our designed evaluation tool and results were automatically evaluated how they are credible and reliable and how they represent different states of emotions. As a result, three final databases were formed. The chapter also describes the idea of new potential model of a complex emotion recognition system as a whole unit.

Two-way relay networks with energy harvesting and information transfer: Throughput performance with distance allocation

In this paper, we analyse the performance analysis for two and three time slot transmission schemes (2TS and 3TS) for two-way Amplify-and-Forward (AF) relaying networks which are developed by wireless power and data transfer, where the energy harvesting (EH) relay node helps interchange information between two nodes. We derive the throughput and the approximate expressions of outage probability of the 2TS, 3TS transmission schemes and compare these results with the distance allocation between source node to relay and relay to destination node, and the large scale path loss in order to observe throughput performance. It is noted that these transmission schemes can significantly enhance the system performance.

A straightforward method to evaluate the energy aware two-way relaying networks under effect of co-channel interference

In the energy harvesting scheme, energy from the received information signal and co-channel interference (CCI) signals is scavenged by the self-power relay before it is used to amplify the received signal and finally transmit to the destination. Particularly, the closed-form outage probability expressions are evaluated for tractable performance analysis. In this paper, we also introduce the results of Monte Carlo simulation to prove the tightness of the proposed approximations outage performance. Additionally, it is assumed that the benefits of CCI signals can extend the lifespan of relaying systems and enhance energy efficiency at the self-power relay.