Communications - Scientific Letters of the University of Zilina, 2012 (vol. 14), issue 2
Articles
Study of the Chalcogenide Nonlinear Fiber Bragg Gratings for All-Optical Switching
Eliska Jurisova, Jarmila Mullerova
Communications - Scientific Letters of the University of Zilina 2012, 14(2):5-10 | DOI: 10.26552/com.C.2012.2.5-10 
In this paper uniform and apodized nonlinear chalcogenide glass fiber Bragg gratings (FBG) as novel and promising devices for all-optical switching are investigated. The transmission response of these devices is discussed theoretically. The continuous wave in the investigated FBGs induces the nonlinear variation of the refractive index that causes changes in the FBG transmission characteristics. This effect can be modified depending on incident light power what is assumed to be due to the optical Kerr effect responsible for optical switching. The incident intensity thresholds of the bistable regimes were analyzed numerically to deduce possible switching...
Access Node Dimensioning for IPTV Traffic Using Effective Bandwidth
Juraj Smiesko, Jana Uramova
Communications - Scientific Letters of the University of Zilina 2012, 14(2):11-16 | DOI: 10.26552/com.C.2012.2.11-16
This article presents a dimensioning of capacity of access node (Black Diamond 12 804R) for IPTV source (6 channels of IPTV), which was one part of our project with Slovak Telecom. We describe IPTV traffic by two mathematic models and use Effective bandwidth for dimensioning of required link capacity with respect to QoS.
Subjective Testing and Objective Modelling of Influence of Different Social Classes to Voice Call Quality Perception
Jan Holub, Pavel Soucek
Communications - Scientific Letters of the University of Zilina 2012, 14(2):17-21 | DOI: 10.26552/com.C.2012.2.17-21
The paper presents the analysis of different perception of quality of transmitted voice by different social classes in conference call. Two different social classes (namely people with great income, who are older than 35 and people with low income, who are younger than 25) have been examined by means of ITU-T P.800 conversational tests. Significant differences in perception between those two classes have been identified.
Optimal and Quasioptimal Algorithms of Distinction of the Compressed Images in Bases of Orthogonal Polynomials
Oleg Vyacheslavovich Chernoyarov, Martin Breznan
Communications - Scientific Letters of the University of Zilina 2012, 14(2):22-26 | DOI: 10.26552/com.C.2012.2.22-26
The synthesis and analysis of effective practically realized algorithms of distinction of signals and images represented in bases of orthogonal polynomials was executed. Influence of distortions at formation of sensed and reference useful signals was considered. Recommendations about application of the synthesized distinction algorithms were formulated.
Istical Characterization of Aerosols' Liquid Water Content and Visibility for Terrestrial FSO Links
Muhammad Saeed Khan, Roberto Nebuloni, Martin Grabner, Carlo Capsoni, Erich Leitgeb, Vaclav Kvicera
Communications - Scientific Letters of the University of Zilina 2012, 14(2):27-32 | DOI: 10.26552/com.C.2012.2.27-32
Liquid water content (LWC) is a microphysical parameter which is used to characterize fog/cloud and other particulates. In the absence of precipitation higher amount of LWC depicts dense fog, significantly reducing visibility and causing performance degradation of free-space optical (FSO) links for a non-negligible amount of time. A measurement campaign in Prague (Czech Republic) has recorded the specific attenuation caused by fog in terrestrial FSO links along with visibility, liquid water content (LWC) and integrated particle surface area (PSA) for operational wave-lengths of 1550 nm and 830 nm (installed at two different path links). This contribution...
A Protocol Review for IPTV and WebTV Multimedia Delivery Systems
Lourdes Beloqui Yuste, Hugh Melvin
Communications - Scientific Letters of the University of Zilina 2012, 14(2):33-41 | DOI: 10.26552/com.C.2012.2.33-41
This paper reviews the key protocols used for multimedia delivery both over privately owned managed IP Networks such as IPTV and public non-managed IP Networks such as WebTV. Within these two worlds, the choice between protocols is based on the characteristics of the multimedia service required, the media server and the client's receiver.Users have different expectations of these two delivery platforms and also of different output devices such as TV, PC, tablet or mobile phone. In an IPTV environment, which is a paid-service, users demand the Quality of Service (QoS) they pay for; different quotas provide different services to users. On the other hand,...
Testing Framework for IMS-Based IPTV
Tatiana Kovacikova, Pavol Segec
Communications - Scientific Letters of the University of Zilina 2012, 14(2):42-47 | DOI: 10.26552/com.C.2012.2.42-47
IPTV (Internet Protocol television) is one of the fast-growing communication services of the past years. Unfortunately, there is a lack of standardized deployed solutions and operators need to to rethink their position before upgrading IPTV solutions for next generation TV (HD TV and 3D TV). An efficient and up-to-date Interoperability Test Specification for IMS-Based IPTV is one of the opportunities for service providers and network operators to evaluate different features and services. TISPAN Release 3 covers many new use cases and features for IPTV (like user generated content, target advertising, etc.) and possible interactions with Voice/Data...
A Survey on Contemporary Terrestrial and Handheld Multimedia Broadcasting Networks
Charalampos N. Pitas, Athanasios D. Panagopoulos, Philip Constantinou
Communications - Scientific Letters of the University of Zilina 2012, 14(2):48-54 | DOI: 10.26552/com.C.2012.2.48-54
Digital video broadcasting (DVB) transmission technologies are suitable for wireless delivery of multimedia content both to static and mobile end-users. On the one hand, DVB-T standard has been adopted for digital terrestrial television (DTT) and it has been further developed into a newer standard, DVB-T2, which was recently finalized. On the other hand, DVB-H is a specification for the transmission of digital TV to handheld user terminals such as smart phones delivering IP-encapsulated data. The combination of satellite and terrestrial DVB technologies is DVB-SH which delivers wide coverage to mobile terminals and promises upgraded services to mobile...
Implementation of IMS Testbeds Using Open Source Platforms
Pavel Segec, Tatiana Kovacikova
Communications - Scientific Letters of the University of Zilina 2012, 14(2):55-62 | DOI: 10.26552/com.C.2012.2.55-62
The IP Multimedia Subsystem (IMS) is a control architecture framework for the Next Generation Network (NGN). It is expected that this new network architecture will provide a new kind of IP multimedia services delivered in network converged environments. The NGN and IMS, even after the years of a standardization effort, are still hot networking topics. One of the communities, which adopt emerging communications standards into their products fast, is the open source community. In present days, there are a few open source products, which allow building the IMS environment. However, there are at least two domains for which they are especially helpful....
Speech Coder Identification Using Chaotic Features Based on Steganalyzer Models
A. Utku Yargicoglu, H. Gokhan Ilk
Communications - Scientific Letters of the University of Zilina 2012, 14(2):63-69 | DOI: 10.26552/com.C.2012.2.63-69
In this study a steganalyzer model based on chaotic features is adapted to codec identification problem. As conventional steganalyzers detect suspected packages buried in bitstreams using statistical analysis, the proposed "speech coder identification" model also reveals the statistical differences of the outputs produced by different speech codecs. Essentially, the design of a coder/codec identifier is equivalent to a classifier training where the chaotic features extracted from the suspicious bitstream samples are used as inputs. During training, weight values which dissociate the codec types best are investigated. Finally, performances of the trained...
Value Network as Part of New Trends in Communication
Jakub Soviar, Josef Vodak
Communications - Scientific Letters of the University of Zilina 2012, 14(2):70-75 | DOI: 10.26552/com.C.2012.2.70-75
This paper deals with the topic of value network importance for the new trends in communication. It describes the main definition of distribution and place, and their relations with the value network. The value network is described as a network of all relevant factors impacting the product where the product is in the network's centre. The case of Apple iPod is provided as an example of the value network. E-commerce and digital distribution are also described in the paper as new communication trends. Discussion deals with main text results and authors' opinions.
Development of Leadership Competence and Self Improvement of the Leaders
Slobodan Ristic, Zoran Cekerevac
Communications - Scientific Letters of the University of Zilina 2012, 14(2):76-81 | DOI: 10.26552/com.C.2012.2.76-81
To be a good leader one always has to have a vision. He knows what he wants to reach and how to get it. In such competitive environment as it is today, leader must prepare himself to daily new challenges. This article deals with leadership, and especially with leader's self improvement and development of leadership competence. Introductory part of the article gives one of possible classifications of leader's skills with a brief explanation of each named skill. There are also given some experiences of some of the most successful world's companies in the area of the strategic rotating and moving managers to appropriate leader's positions. In the article,...
Executive Dashboard Systems for Emergency Management
Adam Zagorecki, Jozef Ristvej, Louis K. Comfort, Tomas Lovecek
Communications - Scientific Letters of the University of Zilina 2012, 14(2):82-89 | DOI: 10.26552/com.C.2012.2.82-89
The executive dashboard systems are a mainstream business intelligence technology. The main idea behind the executive dashboard systems is to deliver information about status of the organization by means of simple, abstract measures of performance and intuitive visualizations. One of the key concerns is preventing information overload. This is achieved by identifying key performance indicators - a set of measures that summarize the key aspects of the organization's performance. This paper investigates the application of the concept of the executive dashboard systems to the context of public emergency management. We identify the key differences between...
Study on Lighting Parameters of Audible and Visual Warning Devices Used by the Police of the Czech Republic
Martin Hrinko, Svetla Fiserova
Communications - Scientific Letters of the University of Zilina 2012, 14(2):90-94 | DOI: 10.26552/com.C.2012.2.90-94
In the article, the authors are concerned with the lighting parameters of audible and visual warning devices used by the Police of the Czech Republic in reaction to European legislation on this issue. The aim of this article is to explain the principle itself and the properties of radiation of light with its photometric specifications that can be evaluated and perceived by human eye, including subsequent negative effects on human health. The article presents a study of evaluation of measured values of luminance, luminous intensity and other photometric quantities of selected audible and visual warning devices used by the Police of the Czech Republic.