AEEE. 2013, vol. 11

Permanent URI for this collectionhttp://hdl.handle.net/10084/96416

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Now showing 1 - 20 out of 58 results

Anomaly-based network intrusion detection methods
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Nevlud, Pavel; Bureš, Miroslav; Kapičák, Lukáš; Zdrálek, Jaroslav
The article deals with detection of network anomalies. Network anomalies include everything that is quite different from the normal operation. For detection of anomalies were used machine learning systems. Machine learning can be considered as a support or a limited type of artificial intelligence. A machine learning system usually starts with some knowledge and a corresponding knowledge organization so that it can interpret, analyse, and test the knowledge acquired. There are several machine learning techniques available. We tested Decision tree learning and Bayesian networks. The open source data-mining framework WEKA was the tool we used for testing the classify, cluster, association algorithms and for visualization of our results. The WEKA is a collection of machine learning algorithms for data mining tasks.
The data extraction using distributed crawler inside multi-agent system
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Tomala, Karel; Plucar, Jan; Dubec, Patrik; Rapant, Lukáš; Vozňák, Miroslav
The paper discusses the use of web crawler technology. We created an application based on standard web crawler. Our application is determined for data extraction. Primarily, the application was designed to extract data using keywords from a social network Twitter. First, we created a standard crawler, which went through a predefined list of URLs and gradually download page content of each of the URLs. Page content was then parsed and important text and metadata were stored in a database. Recently, the application was modified in to the form of the multi-agent system. The system was developed in the C# language, which is used to create web applications and sites etc. Obtained data was evaluated graphically. The system was created within Indect project at the VSB-Technical University of Ostrava.
Problem of channel utilization and merging flows in buffered optical burst switching networks
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Kozák, Miloš; Jaumard, Brigitte; Boháč, Leoš
In the paper authors verify two problems of methods of operational research in optical burst switching. The first problem is at edge node, related to the medium access delay. The second problem is at an intermediate node related to buffering delay. A correction coefficient K of transmission speed is obtained from the first analysis. It is used in to provide a full-featured link of nominal data rate. Simulations of the second problem reveal interesting results. It is not viable to prepare routing and wavelength assignment based on end-to-end delay, i.e. link's length or number of hops, as commonly used in other frameworks (OCS, Ethernet, IP, etc.) nowadays. Other parameters such as buffering probability must be taken into consideration as well. Based on the buffering probability an estimation of the number of optical/electrical converters can be made. This paper concentrates important traffic constraints of buffered optical burst switching. It allows authors to prepare optimization algorithms for regenerators placement in CAROBS networks using methods of operational research.
The analysis of SUCCESS HPON networks using the HPON network configurator
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Roka, Rastislav
NG-PON systems present optical access infrastructures to support various applications of the many service providers. In the near future, we can expect NG-PON technologies with different motivations for developing of HPON networks. The HPON is a hybrid passive optical network in a way that utilizes on a physical layer both TDM and WDM multiplexing principles together. The HPON network utilizes similar or soft revised topologies as TDM-PON architectures. In this first paper, design requirements for SUCCESS HPON networks are introduced. A main part of the paper is dedicated to presentation of the HPON network configurator that allows configurating and analyzing the SUCCESS HPON characteristics from a viewpoint of various specific network parameters. Finally, a short introduction to the comparison of the SUCCESS and SARDANA HPON networks based on simulation results is presented.
Room thermostat with servo controlled by PIC microcontroller
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Skapa, Jan; Kramář, Petr
This paper describes the design of room thermostat with Microchip PIC microcontroller. Thermostat is designated for two-pipe heating system. The microprocessor controls thermostatic valve via electric actuator with mechanical gear unit. The room thermostat uses for its activity measurements of air temperature in the room and calorimetric measurement of heat, which is served to the radiator. These features predestinate it mainly for underfloor heating regulation. The thermostat is designed to work in a network. Communication with heating system's central control unit is proceeded via RS485 bus with proprietary communication protocol. If the communication failure occurs the thermostat is able to work separately. The system uses its own real time clock circuit and memory with heating programs. These programs are able to cover the whole heating season. The method of position discontinuous PSD control is used in this equipment.
Wearable textile electrodes for ECG measurement
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Vojtěch, Lukáš; Bortel, Radoslav; Neruda, Marek; Kozák, Miloš
The electrocardiogram (ECG) is one of the most important parameters for monitoring of the physiological state of a person. Currently available systems for ECG monitoring are both stationary and wearable, but the comfort of the monitored person is not at a satisfactory level because these systems are not part of standard clothing. This article is therefore devoted to the development and measurement of wearable textile electrodes for ECG measurement device with high comfort for the user. The electrode material is made of electrically conductive textile. This creates a textile composite that guarantees high comfort for the user while ensuring good quality of ECG measurements. The composite is implemented by a carrier (a T-shirt with flame retardant) and sensing electrodes embroidered with yarn based on a mixture of polyester coated with silver nanoparticles and cotton. The electrodes not only provide great comfort but are also antibacterial and antiallergic due to silver nanoparticles.
Modelling of H.264 MPEG2 TS traffic source
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Kľúčik, Stanislav; Lackovič, Martin
This paper deals with IPTV traffic source modelling. Traffic sources are used for simulation, emulation and real network testing. This model is made as a derivation of known recorded traffic sources that are analysed and statistically processed. As the results show the proposed model causes in comparison to the known traffic source very similar network traffic parameters when used in a simulated network.
Categorization of unorganized text corpora for better domain-specific language modeling
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Staš, Ján; Zlacký, Daniel; Hládek, Daniel; Juhár, Jozef
This paper describes the process of categorization of unorganized text data gathered from the Internet to the in-domain and out-of-domain data for better domain-specific language modeling and speech recognition. An algorithm for text categorization and topic detection based on the most frequent key phrases is presented. In this scheme, each document entered into the process of text categorization is represented by a vector space model with term weighting based on computing the term frequency and inverse document frequency. Text documents are then classified to the in-domain and out-of-domain data automatically with predefined threshold using one of the selected distance/similarity measures comparing to the list of key phrases. The experimental results of the language modeling and adaptation to the judicial domain show significant improvement in the model perplexity about 19 % and decreasing of the word error rate of the Slovak transcription and dictation system about 5,54 %, relatively.
Unsupervised spelling correction for Slovak
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Hládek, Daniel; Staš, Ján; Juhár, Jozef
This paper introduces a method to automatically propose and choose a correction for an incorrectly written word in a large text corpus written in Slovak. This task can be described as a process of finding the best matching sequence of correct words to a list of incorrectly spelled words, found in the input. Knowledge base of the classification system - statistics about sequences of correctly typed words and possible corrections for incorrectly typed words can be mathematically described as a hidden Markov model. The best matching sequence of correct words is found using Viterbi algorithm. The system will be evaluated on a manually corrected testing set.
Comparison among models to estimate the shielding effectiveness applied to conductive textiles
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Lopéz, Alberto; Vojtěch, Lukáš; Neruda, Marek
The purpose of this paper is to present a comparison among two models and its measurement to calculate the shielding effectiveness of electromagnetic barriers, applying it to conductive textiles. Each one, models a conductive textile as either a (1) wire mesh screen or (2) compact material. Therefore, the objective is to perform an analysis of the models in order to determine which one is a better approximation for electromagnetic shielding fabrics. In order to provide results for the comparison, the shielding effectiveness of the sample has been measured by means of the standard ASTM D4935-99.
A methodology for measuring voice quality using PESQ and interactive voice response in the GSM channel designed by OpenBTS
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Partila, Pavol; Kohut, Marek; Vozňák, Miroslav; Mikulec, Martin; Šafařík, Jakub; Tomala, Karel
This article discusses a methodology for rating the quality of mobile calls. Majority telecommunications service from the perspective of the whole world is using mobile telephony networks. One of the problems affecting this service and its quality are landscape barriers, which prevent the spread signal. Price and complex construction of classic BTS does not allow their dense distribution. In such cases, one solution is to use OpenBTS technology. Design of OpenBTS is more available, so it can be applied to much more places and more complex points. Purpose of this measurement is a model for effective stations deployment, due to shape and distribution of local barriers that reduce signal power, and thus the quality of speech. GSM access point for our mobile terminals is OpenBTS USRP N210 station. The PESQ method for evaluating of speech quality is compared with the subjective evaluation, which provides Asterisk PBX with IVR call back. Measurement method was taken into account the call quality depending on terminal position. The measured results and its processing bring knowledge to use this technology for more complicated locations with degraded signal level and increases the quality of voice services in telecommunications.
Admission control in IMS networks
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Chromý, Erik; Jadroň, Marcel; Kavacký, Matej; Kľúčik, Stanislav
In our paper there is an emphasis on simulations of admission control methods in MATLAB environment. The main task of admission control method is to make a decision if the connection requiring network access should be accepted to the network or the access should be rejected. If the connection is accepted to the network, the admission control has to ensure that Quality of Service of this connection will be satisfied, as well as Quality of Service of all other existing connections. We have observed several Measurement based admission control algorithms and the result is the identification of the suitable algorithm which can estimate the required bandwidth.
Performance analysis of IMS network: the proposal of new algorithms for S-CSCF assignment
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Nagy, Ľuboš; Novotný, Vít; Uramová, Jana; Makhlouf, Nermin
This article is focused on the proposal of three load balancing methods which can be used for a selection of S-CSCF (Serving-Call Session Control Server) server in IP Multimedia Subsystem (IMS) during the registration procedures of subscribers. All presented methods are implemented and evaluated for various inter-arrival and service times in the mathematical model based on queueing theory. In this article, two methods based on performance parameters (such as utilizations, etc.) and one method based on number of registered subscribers to each of available S-CSCF server are described. The main advantage of third method is that all related information is obtained from traffic analysis through I-CSCF (Interrogating-CSCF) node. Also, the designed methods are compared with other selection algorithms presented in previous research works by others researchers (Hwang et col., Cho et col. or Tirana et col.). The article shows that the implemented methods can optimize the service latency of whole IMS network.
Vehicular networks and road safety: an application for emergency/danger situations management using the WAVE/802.11p standard
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Fazio, Peppino; De Rango, Floriano; Lupia, Andrea
Car-to-car communication makes possible offering many services for vehicular environment, mainly to improve the safety. The decentralized kind of these networks requires new protocols to distribute information. The advantages that it offers depend on the penetration rate, that will be enough only after years since the introduction, due to the longevity of the current cars. The V2X communication requires On-Board Units (OBUs) in the vehicles, and Road-Side Units (RSUs) on the roads. The proposed application uses the peculiarities of the VANETs to advise danger or emergency situations with V2V and V2I message exchange. IEEE 802.11p is standard on which the communication is based, that provides the physical and the MAC layers. The WAVE protocol uses this standard, implementing other protocols defined by the family of standards IEEE P1609 in the upper layers. They define security services, resource management, multichannel operations and the message exchange protocol in WAVE. The performance of the application will be evaluated through many simulations executed in different scenarios, to provide general data independent from them.
Vehicular networking enhancement and multi-channel routing optimization, based on multi-objective metric and minimum spanning tree
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Fazio, Peppino; Sottile, Cesare; Santamaria, Amilcare Francesco; Tropea, Mauro
Vehicular Ad hoc NETworks (VANETs) represent a particular mobile technology that permits the communication among vehicles, offering security and comfort. Nowadays, distributed mobile wireless computing is becoming a very important communications paradigm, due to its flexibility to adapt to different mobile applications. VANETs are a practical example of data exchanging among real mobile nodes. To enable communications within an ad-hoc network, characterized by continuous node movements, routing protocols are needed to react to frequent changes in network topology. In this paper, the attention is focused mainly on the network layer of VANETs, proposing a novel approach to reduce the interference level during mobile transmission, based on the multi-channel nature of IEEE 802.11p (1609.4) standard. In this work a new routing protocol based on Distance Vector algorithm is presented to reduce the delay end to end and to increase packet delivery ratio (PDR) and throughput in VANETs. A new metric is also proposed, based on the maximization of the average Signal-to-Interference Ratio (SIR) level and the link duration probability between two VANET nodes. In order to relieve the effects of the co-channel interference perceived by mobile nodes, transmission channels are switched on a basis of a periodical SIR evaluation. A Network Simulator has been used for implementing and testing the proposed idea.
Development of the real time situation identification model for adaptive service support in vehicular communication networks domain
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Kurmis, Mindaugas; Andziulis, Arūnas; Dzemydiene, Dale; Jakovlev, Sergej; Vozňák, Miroslav; Drungilas, Darius
The article discusses analyses and assesses the key proposals how to deal with the situation identification for the heterogeneous service support in vehicular cooperation environment. This is one of the most important topics of the pervasive computing. Without the solution it is impossible to adequately respond to the user's needs and to provide needed services in the right place at the right moment and in the right way. In this work we present our developed real time situation identification model for adaptive service support in vehicular communication networks domain. Our solution is different from the others as it uses additional virtual context information source - information from other vehicles which for our knowledge is not addressed in the past. The simulation results show the promising context exchange rate between vehicles. The other vehicles provided additional context source in our developed model helps to increase situations identification level.
Modeling of telecommunication cables for gigabit DSL application
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Nevosad, Marek; Lafata, Pavel; Jareš, Petr
The first part of our paper brings the description and analysis of method used for modeling of metallic cable’s parameters according to the modified KPN model. Moreover we were able to perform measurements and estimations for real metallic cable’s with various transmission characteristics and constructional arrangement, for which we derived the necessary parameters of a new modeling method. Following part contains the comparison of measured characteristics with their models according to the modified KPN model. Finally, we discussed obtained results.
OpenFlow deployment and concept analysis
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Hégr, Tomáš; Boháč, Leoš; Uhlíř, Vojtěch; Chlumský, Petr
Terms such as SDN and OpenFlow (OF) are often used in the research and development of data networks. This paper deals with the analysis of the current state of OpenFlow protocol deployment options as it is the only real representative protocol that enables the implementation of Software Defined Networking outside an academic world. There is introduced an insight into the current state of the OpenFlow specification development at various levels is introduced. The possible limitations associated with this concept in conjunction with the latest version (1.3) of the specification published by ONF are also presented. In the conclusion there presented a demonstrative security application addressing the lack of IPv6 support in real network devices since most of today's switches and controllers support only OF v1.0.
Fault tolerant ethernet based network for time sensitive applications in electrical power distribution systems
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Boháč, Leoš; Vodrážka, Jiří
The paper analyses and experimentally verifies deployment of Ethernet based network technology to enable fault tolerant and timely exchange of data among a number of high voltage protective relays that use proprietary serial communication line to exchange data in real time on a state of its high voltage circuitry facilitating a fast protection switching in case of critical failures. The digital serial signal is first fetched into PCM multiplexer where it is mapped to the corresponding E1 (2 Mbit/s) time division multiplexed signal. Subsequently, the resulting E1 frames are then packetized and sent through Ethernet control LAN to the opposite PCM demultiplexer where the same but reverse processing is done finally sending a signal into the opposite protective relay. The challenge of this setup is to assure very timely delivery of the control information between protective relays even in the cases of potential failures of Ethernet network itself. The tolerance of Ethernet network to faults is assured using widespread per VLAN Rapid Spanning Tree Protocol potentially extended by 1+1 PCM protection as a valuable option.
Availability model for virtualized platforms
(Vysoká škola báňská - Technická univerzita Ostrava, 2013) Hlaváček, Jiří; Bešťák, Robert
Network virtualization is a method of providing virtual instances of physical networks. Virtualized networks are widely used with virtualized servers, forming a powerful dynamically reconfigurable platform. In this paper we discuss the impact of network virtualization on the overall system availability. We describe a system reflecting the network architecture usually deployed in today’s data centres. The proposed system is modelled using Markov chains and fault trees. We compare the availability of virtualized system using standard physique network with the availability of virtualized system using virtualized network. Network virtualization introduces a new software layer to the network architecture. The proposed availability model integrates software failures in addition to the hardware failures. Based on the estimated numerical failure rates, we analyse system’s availability.

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