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Ing. Zbyněk Kocur, Ph.D.

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Technologie internetu věcí v prostředí chytrého měření

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Pojem technologie internetu věcí (IoT – Internet of Things) se již před nějakou dobou napevno etabloval v našich domácnostech v podobě různých systémů domácích automatizací a doplňků, které se snaží zpříjemnit náš každodenní život (inteligentní zásuvky, žárovky, LED pásky, vytápění, domácí asistenti apod.). Technologie internetu věcí se stala také nedílnou součástí koncepce Smart City a strategie Průmyslu 4.0. Díky masivnímu nasazení vzájemně spolupracujících zařízení lze provádět řadu úloh automatizovaně bez nutnosti obsluhy. Stejně jako jiná průmyslová odvětví i energetika pomalu podléhá trendům využívající vzájemnou komunikaci a technologie internetu věcí pronikají i do této oblasti. Jednou z typických aplikací je sběr dat z různých bodů distribuční sítě. V článku je představeno řešení vyvinuté na katedře telekomunikační techniky, FEL, ČVUT v Praze.

Verification of a new metric for data flow continuity and sustainability optimization

  • DOI: 10.1002/dac.4890
  • Odkaz: https://doi.org/10.1002/dac.4890
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This article presents a verification process of a new metric designed for transmission continuity optimization. Unlike the commonly used metrics, it focuses solely on flow continuity and sustainability, disregarding the maximization of throughput or minimization of latency. We base our metric on inter-packet gaps analysis and ordering of packets from multiple communication flows into a final flow. We also compare our metric with the commonly used one based on Jain's fairness index in cases when optimization of communication flow sustainability is the priority. We present the evaluation of results and analyze the data processing complexity. Moreover, we discuss the weaknesses and strengths of different approaches to communication flow optimization.

Experimental Setup for Testing of Communication Systems and Services in Engineering Education

  • DOI: 10.1109/EAEEIE46886.2019.9000470
  • Odkaz: https://doi.org/10.1109/EAEEIE46886.2019.9000470
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    A system for data stream generation and analysis and a remotely controlled emulator of communication channel were designed, assembled and tested at our department. Communication technologies for Internet access (NGA), Smart Grid and other industrial use can be tested and presented in engineering education with the help of these systems. Test conditions close to real situations can be simulated by the devices (for example testing and measurement of mobile network services and fixed access, testing of parameters of power line communication systems for industrial use, etc.). Practical experience from laboratory education is presented and discussed in this paper.

Použití otevřených nástrojů pro testování přístupových sítí nové generace

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Metodika testování přístupových sítí je založena na dokumentech BEREC a ČTÚ. Lze předpokládat, že se dále budou zpřísňovat doporučené parametry v souvislosti s výhledem na tzv. sítě s velmi vysokou kapacitou v horizontu roku 2025. Přístup k Internetu tedy už dnes není negarantovanou „best effort“ službou. Proto také vzrůstá potřeba ověřovat parametry přípojek. V tomto článku jsou představeny základní metodické přístupy a nástroje, které na základě našich zkušeností doporučujeme k praktickému využití. Nad otevřenými nástroji, jako je iPerf a FlowPing jsme vyvinuli nadstavbovou platformu, která usnadní vyhodnocení testů, zvláště těch, které používají více různých toků jak souběžně, tak i v postupných po sobě následujících krocích.

Remote Controlled Emulator of Communication Channel for Industrial Testing

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The prototype of remote-controlled emulator of communication channel was designed, assembled and tested in industry use-case. The radiocommunication channel in mobile network and wired channel in fixed network, for example broadband power line, can be emulated. The communication technologies for Smart Grid, Smart Cities and Industry 4.0 can be tested and verificated with designed emulator. The channel capacity, data performance, error rate and other parameters of the communication systems are depended on the signal-tonoise ratio. The test conditions nearly real systems can be emulated by the laboratory devices. Simply, the attenuator sets value of the signal on input of receiver, the generator sets value of the noise in communication channel.

Transmission Optimization Metrics Setup Issues in the Field of Time Constrained Communications

  • DOI: 10.3390/s18093104
  • Odkaz: https://doi.org/10.3390/s18093104
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This article introduces a new approach in the field of network optimization based on Transmission Optimization Metric (TOM), which is aimed at improving traffic flow continuity and increasing the chances for traffic flow sustainability in a way that helps to minimize inter-packet gaps.

Simulation of the Application Layer in NarrowBand Networks with Conditional Data Injection XML Scheme Based on Universal Data Generator

  • DOI: 10.15598/aeee.v15i4.2454
  • Odkaz: https://doi.org/10.15598/aeee.v15i4.2454
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    In this article, we would like to deal with challenges and analysis approaches in the area of narrow band communication networks. Especially those networks which use TCP/IP protocol family. We also present a new universal data generator for OMNeT++ simulation environment. We created this generator to satisfy the evaluation, stress testing and benchmarking demands of more and more complex industrial and the Internet of Things networks. We also present the methods for evaluation and comparison of results obtained from simulated and real TCP/IP based networks in this article.

On Limits of Embedded Systems in Network Packet Processing

  • DOI: 10.15598/aeee.v14i4.1835
  • Odkaz: https://doi.org/10.15598/aeee.v14i4.1835
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The paper deals with a measurement of single-hop one way packet delay on embedded systems used for networking. The single-hop one way packet delay is essential parameter when we need to process packets with strict delivery time constrains. Comparison of different approaches to single-hop one way packet delay measurements is presented in this work along with discussion about strong and weak points in specific measurement approach. The impact of different types of system load and number of CPU cores are also covered by presented results. The presented results of measurement single-hop one way packet delay in embedded Linux system show that for the specific system configuration the packet processing delay depends (in different ways) on system load and network stack load.

Performance Evaluation of IoT Mesh Networking Technology in ISM Frequency Band

  • Autoři: Ing. Ondřej Vondrouš, Ph.D., Ing. Zbyněk Kocur, Ph.D., Hégr, T., Slavíček, O.
  • Publikace: Proceedings of the 2016 17th International Conference on Mechatronics - Mechatronika (ME) 2016. Prague: Czech Technical University in Prague, Faculty of Electrical Engineering, 2016. pp. 488-495. ISBN 978-80-01-05883-1.
  • Rok: 2016
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The paper deals with a performance evaluation and stress-testing of IoT (Internet of Things) based networks operating at 868 MHz ISM (Industrial, Science, Medical) frequencies. The importance of this specific ISM frequency band is increasing over the time as it is utilized by data acquisition from increasing number of sensors in IoT, industrial automation and logistics segment. As the number of network devices in ISM frequency band is rapidly increasing, the identification of technology limits is crucial for future deployment of IoT networks in areas with a high interference potential. The interference is the main cause of the degradation in communication stability among IoT devices and decreasing QoS (Quality of Service). It is necessary to know the limits of deployed IoT network technology under optimal and sub-optimal conditions. Only the monitoring of network along with knowledge of exact limits specific for the network can ensure a certain level of provided services.

Testing Methodology for Performance Evaluation of Communication Systems for Smart Grid

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The paper presents a methodology proposal for testing and evaluation of communication systems in Smart Grids, especially for Power Line Communication (PLC) systems. The PLC technology is widely used in power grid as a part of Advanced Metering Infrastructure (AMI) allowing mainly data transfers between a management system at utility and customer-premises smart meters. However, the PLC technology on medium voltage (MV) lines is often used for remote control and monitoring of distribution transformers as well. Since power grid and consequently power lines have different transmission parameters affected by their placement and potentially burdened by interferences, the PLC systems have to be evaluated on site before placed to production. In this paper, authors propose a methodology for long-term benchmarking of the PLC systems using newly developed testing tools. The methodology is subsequently tested on real power grid and a selection of results is presented.

CER/TER - The New Metric for TCP Connection Robustness Evaluation and Comparison

  • DOI: 10.15598/aeee.v13i5.1500
  • Odkaz: https://doi.org/10.15598/aeee.v13i5.1500
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This article presents new metric for TCP connection robustness evaluation and comparison. This metric is focused on TCP connection and transmission continuity rather then on maximal throughput or minimal RTT. This metric is developed especially for evaluation of narrow band networks. That is why it is very convenient to use this metric for networks such as Internet of Things networks or industrial sensor networks. Our metric is based on observing if connections or transmissions are successfully finished or not. It is possible to optimize this metric for specific situations. This metric can be used in both the real networks and in discrete simulation environments.

FlowPing - The New Tool for Throughput and Stress Testing

  • DOI: 10.15598/aeee.v13i5.1497
  • Odkaz: https://doi.org/10.15598/aeee.v13i5.1497
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This article presents a new tool for network throughput and stress testing. The FlowPing tool is easy to use, and its basic output is very similar to standard Linux ping application. The FlowPing tool is not limited to reach-ability or round trip time testing but is capable of complex UDP based throughput stress testing with rich reporting capabilities on client and server sides. Our new tool implements features, which allow the user to perform tests with variable packet size and traffic rate. All these features can be used in one single test run. This allows the user to use and develop new methodologies for network throughput and stress testing. With the FlowPing tool, it is easy to perform the test with the slowly increasing the amount of network traffic and monitor the behavior of network when the congestion occurs.

Testing, Troubleshooting and Modelling Tools for Communication Part of Smart Grid

  • DOI: 10.1109/SCSP.2015.7181561
  • Odkaz: https://doi.org/10.1109/SCSP.2015.7181561
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This paper deals with a data transfer testing and modeling in communication networks supporting energy distribution. The concept of Smart Grid, which promises highly efficient and dynamic energy systems, has to be backed by convenient communication systems. The contemporary electrical grid incorporate some form of the digital communication to be able to deliver desired availability and reliability at all levels. This means that the communication systems are inseparable from the electrical grid itself. While power-engineering uses well proven methods for the grid testing, the data networking, in this particular area, is still evolving. The paper analyses advanced methods for testing and modeling of data transfers in communication networks and presents selected practical experience.

Adaptable System Increasing the Transmission Speed and Reliability in Packet Network by Optimizing Delay

  • DOI: 10.15598/aeee.v12i1.878
  • Odkaz: https://doi.org/10.15598/aeee.v12i1.878
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    here is a great diversity in the transmission technologies in current data networks. Individual technologies are in most cases incompatible at physical and partially also at the link layer of the reference ISO/OSI model. Network compatibility, as the ability to transmit data, is realizable through the third layer, which is able to guarantee the operation of the different devices across their technological differences. The proposed inverse packet multiplexer addresses increase of the speed and reliability of packet transmission to the third layer, and at the same time it increases the stability of the data communication by the regulation of the delay value during the transmission. This article presents implementation of a communication system and its verification in real conditions. The conclusion compares the strengths and weaknesses of the proposed control system.

Multipath TCP in LTE Networks

  • DOI: 10.15598/aeee.v14i4.1210
  • Odkaz: https://doi.org/10.15598/aeee.v14i4.1210
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The results of experiments with Multipath TCP (Multipath Transmission Control Protocol) in LTE (3GPP Long Term Evolution) networks are presented. Our results show increased resiliency and availability of network Multipath TCP connection. Using multiple sub-flows over diverse network paths inside Multipath TCP session results in greatly increased bandwidth and availability. When Multipath TCP is used the behavior of this protocol is consistent in situation of adding new sub-flow or removing flow on a faulty line. Different strategies for path selection are possible with great impact on Multipath TCP session performance. Network structure consisting of few connections with similar parameters is optimal for full mesh Multipath TCP path topology. In this case the behavior of Multipath TCP predictable.

Procedure to Measure of the Data Transmission Speed in LTE Mobile Networks

  • DOI: 10.1109/MECHATRONIKA.2014.7018335
  • Odkaz: https://doi.org/10.1109/MECHATRONIKA.2014.7018335
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The methodology specifies a procedure for measuring of data transmission speed for the assessment of compliance with the conditions proscribed for holders of licenses for usage frequencies in the 800, 1800 and 2600 MHz bands, for the operation of mobile systems according to the LTE standard. The achievement of specified data transmission speed is a key parameter for evaluating the coverage of the Czech Republic mobile signal for the LTE standard systems. The methodology allows to the Czech telecommunication regulatory body (Czech Telecommunication Office – CTO), telecommunications operators and end users unambiguous determination of values of speed of data transmission in mobile networks in accordance with standard LTE. The methodology treats the issue comprehensively and specifies in initial conditions of measurement, measurement procedures (both for stationary measurement and in motion measurement) and related calculations. The team of authors from the Czech Technical University in Prague created a substantial part of the described methodology.

Quality of Service and Experience – Business Driven Standardisation for Interoperability in Internet of Things

  • Pracoviště: Katedra elektroenergetiky, Katedra telekomunikační techniky
  • Anotace:
    The phenomenon of the Internet of Things (IoT) brings not only new opportunities in services, but also the requirements for interoperability of various existing technologies and technological systems in converged world. Complex system IoT thus forms a kind of umbrella, allowing more business opportunities. Implementation of modern communication and technology brings great potential especially in the telecommunications, energy, transport and logistic. This article is devoted to the description of opportunities and threats that arise from a new comprehensive system of IoT in individual sectors. It will be also shown that the main measurable criteria to provide the services required in this complex system are to meet the quality of service QoS and quality of experience QoE. It will be shown that these two main criteria are common to all sectors roofed under the umbrella of the Internet of Things in future converged world.

Reduction of Packet Loss by Optimizing the Antenna System and Layer 3 Coding

  • DOI: 10.15598/aeee.v12i4.1205
  • Odkaz: https://doi.org/10.15598/aeee.v12i4.1205
  • Pracoviště: Katedra elektromagnetického pole, Katedra telekomunikační techniky
  • Anotace:
    he article describes the verification of the application of methods of network coding in the mobile wireless network environment with specific antenna system in use. Network coding principles are used for increase the reliability of data transmission. The proposed principles are demonstrated by modelling of the transmission system using data from real mobile networks. The effectiveness of network coding for deployment in wireless mobile networks is demonstrated on the basis of simulation in the simulation environment Omnet++. The input data of the simulation model are obtained by measuring in real mobile network of 2nd generation.

Measurement of Mobile Communication Devices on the Testing Railway Ring

  • Pracoviště: Katedra telekomunikační techniky, Katedra počítačů
  • Anotace:
    Paper describes results from the measurement of the transmission system that is designed for active backup of transmission lines through mobile networks. Measurements have been designed and implemented to verify the ability of uninterruptible data transfer during train movement in places with different quality of mobile networks. Testing was realized on the Small test ring of the Railway Research Institute in Velim. We present the results of the measurement on the physical, link and network layer of the reference model ISO / OSI, including results evaluation.

Methodology of the Direct Measurement of the Switching Latency

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The article provides a measurement methodology based on the related RFCs. It brings a solution of determining the switching la tency on the physical layer using common measuring devices. As a proof of concept were done a number of the experimental measurements, including analysis of the results. Switching latency is an important performance parameter which participates in the decision-making whether to deploy the switch to low-latency environments. This is especially important in industrial networks for real-time systems involving smart grids. Determine the value of the switching latency is also an important step in the eventual deployment of the OpenFlow technology on this field.

RFID technology in industrial environments with risk of explosion

  • Autoři: Stasa, P., Svub, J., Ing. Zbyněk Kocur, Ph.D., Unucka, J.
  • Publikace: Proceedings of International Symposium on Earth Science and Technology 2013. Kyoto: Kyoto University, 2013. pp. 123-128. ISBN 978-4-9902356-2-8.
  • Rok: 2013
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    We describe the issues of the safety ensuring production management in industrial environments where automation systems must be subject to strict specific regulations. Such environments can be found in many industrial sectors, we can talk about mining industry, automotive, manufacturing, handling and generally about storage of industrial gases, batteries, etc. Electrical equipment and means of automation techniques used in environments with risk of explosion are special categories of electrical equipment, which are a potential danger for the user. It is not for them only to ensure safety against electrical shock, but especially for such protection when operating in potentially explosive atmospheres where it represents a dangerous source of ignition explosion. The article pays particular attention to elements of automatic identification technology based on RFID, which can be used for tracking and identifying objects in logistics processes. The use of these identifiers in an environment with danger of explosion is the subject of this article.

Simulation of the Data Transmission from the Aerobatic Plane

  • Autoři: Chlumský, P., Ing. Zbyněk Kocur, Ph.D., Machula, V.
  • Publikace: Przeglad Elektrotechniczny. 2013, 89(2b/2013), 199-204. ISSN 0033-2097.
  • Rok: 2013
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This article deals with the optimization of data transmission from the fast-moving objects. Optimization is performed on the second layer of the RM OSI and uses multiple transmission channels. For simulation were created two cases using multiple transmission channels. These cases were compared with case of common wireless system with a single channel. Proposed cases reached better error rates and proved their usefulness. They are also independent on the transmission technology (due to implementation on the second layer of RM OSI), therefore are versatile.

Comparison Methodology of the Simulation Models Based on the IEEE 802.11 Standard

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The article describes the methodology of comparison between the real wireless technology and its simulation model. The methodology is focused on the technology based on the standard IEEE 802.11g and on the simulation environment OMNeT++ supplemented by the INETMANET library. The proposed methodology is universal and can be used for other comparison of real communication technology implementation and its simulation.

Comparison of Different Scenarios for Path Diversity Packet Wireless Networks

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This article discusses the use of the principles of network coding in wireless networks to increase the overall robustness of the transmission. Path diversity on the packet level is investigated as a software alternative to classical diversity techniques commonly used to improve wireless devices communication. The article describes the initial stage of the research of network coding in elementary form with network traffic duplication. Objects of investigation are two different types of transmission in two scenarios, where the resulting transmission loss is evaluated with dependency on the packet length.

IPv6 Fragmentation and Path MTU Discovery Simulation Model for OMNeT++

  • Autoři: Čepa, L., Ing. Zbyněk Kocur, Ph.D., Kozák, M.
  • Publikace: Research in Telecommunication Technologies Conference proceedings and Workshop. Žilina: Žilinská univerzita, 2012. pp. 113-118. ISBN 978-80-554-0570-4.
  • Rok: 2012
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This paper presents the logic, design and performance results of implementation of IPv6 Fragmentation and Path MTU Discovery processes for IPv6 in the OMNeT++ discrete event simulator based on the related RFC documents. It describes the necessary modifications to relevant modules and the simulation model integrated into the INET-20111118 framework for OMNeT++. The simulation model is used to verify proper functionality of the implemented processes. It also describes the methodology for comparison this model with the real implementations of both processes. The methodology is based on a comparison of the measurement RTT for TCP connection. The proper functionality of implemented processes into INET-20111118 framework is verified by using this methodology.

Migration of the IT Technologies to the Smart Grids

  • DOI: 10.5755/j01.eee.123.7.2390
  • Odkaz: https://doi.org/10.5755/j01.eee.123.7.2390
  • Pracoviště: Katedra elektroenergetiky, Katedra telekomunikační techniky
  • Anotace:
    This paper describes the migration of the traditional IT technologies to the Industrial Control Networks for Power Grids (ICNPG), characteristics of the typical ICNPG network and the differences between them and ICT network. We define the availability and reliability of the ICT networks and describe the current trends of the IT technologies in the ICNPG network with regarding its use in the Smart Grids. Finally, we describe the Smart Grid technology and summarize the availability and reliability of the ICNPG networks from technical studies. The comparison of ICNPG and ICT networks show that the utilization rate of ICT technologies must be determined in the Smart Grids with regard to the required availability and reliability. Ill. 1, bibl. 7, tabl. 2 (in English; abstracts in English and Lithuanian).

Praktické provedení konfigurace DNS serveru a koncových stanic v síti IP verze 6

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Předchozí článek poskytl praktickou ukázku adresace koncové sítě IPv6 a nastavení automatické konfigurace. Tento článek se zabývá praktickým postupem konfigurace DNS serveru a koncových stanic s operačními systémy Microsoft Windows XP, Microsoft Windows 7 a Ubuntu v experimentální síti IPv6 se směrovačem Mikrotik a servery založenými na Scientific Linux.

The Methodology for the Selection of ICT Technologies for Smart Grids

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The paper introduces Smart Grids and the methodology for the selection of ICT technologies for them. It describes the quality and implementation-operating parameters for evaluation ICT technologies and services and applications running in Smart Grids. The methodology is based on a comparison of these parameters. This methology is also based on the availability and reliability of ICT technologies, which are described in this paper.

Comparison Methodology of the Simulation Models in Wireless Networks

  • Autoři: Chlumský, P., Ing. Zbyněk Kocur, Ph.D., doc. Ing. Jiří Vodrážka, Ph.D.,
  • Publikace: 13th International Conference on Research in Telecommunication Technologies 2011. Brno: VUT v Brně, Fakulta elektrotechniky a komunikačních technologií, 2011. pp. 10-14. ISBN 978-80-214-4283-2.
  • Rok: 2011
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The article is focused on the description of the measurement method and comparison of the real technology based on the standard IEEE 802.11g (Wi-Fi) with the model used in the simulation environment OMNET++. The simulation model, which is done, is used for simulation and optimization of the wireless protocol. The same protocol is used for high-speed data transmission from the fast moving objects too. In the article, the real implementation of the IEEE 802.11 protocol is compared with the simulation on the comparison basis of the signal noise ratio, receives the sensitivity and throughput for the Free Space Loss model which is emerging from the previous one which was described above.

Delay Model of RTP Flows in Accordance with M/D/1 and M/D/2 Kendall's Notation

  • Autoři: Vozňák, M., Halas, M., Borowik, B., Ing. Zbyněk Kocur, Ph.D.,
  • Publikace: International Journal of Mathematics and Computers in Simulation. 2011, 5(3), 242-249. ISSN 1998-0159.
  • Rok: 2011
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This article deals with the mathematical model of an end-to-end delay and a delay variation in VoIP connections going through a two priority queue' serving system. We focused on delay caused by network components and its mathematical formulations. Our mathematical computational model is able to predict an estimated delay of packets in RTP flows, especially dealy variation in routers handling RTP packets in priority queue. We applied M/D/1 and M/D/2 queuing models and we expressed a probability of RTP packets waiting in the queue and all partial delay components and mechanisms. We determined the domain of validity in performed experiments and the proposed mathematical model is suitable for the approximation of voice traffic in network with priority queuing which consists of sources with the Poisson's probability distribution.

Filtering Methods of the Inertial Position Measuring System

  • Autoři: Machula, V., Ing. Zbyněk Kocur, Ph.D., Chlumský, P.
  • Publikace: Proceedings of the 2011 International Conference on Telecommunication Systems Management. Dallas, TX: American Telecommunications Systems Management Association Inc., 2011. pp. 35-38. ISBN 978-0-9820958-4-3.
  • Rok: 2011
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This paper describes a part of experimental project focused on inertial position measurement. Paper aims to filtering process of position and attitude estimation. In addition, the position evaluation process contains three filtering steps. Those steps are described separately. Inertial measuring unit (IMU) use a MEMS (Microelectromechanical Systems) technology sensors in specific application. This application is a tracking of the aerobatic aircraft flight path. Measurement by MEMS inertial sensors in this application is influenced by many types of noise. Described three step filtering process is trying to remove position and attitude error as much as possible.

Simulation of Data Transfer from the Aerobatic Plane

  • Autoři: Chlumský, P., Ing. Zbyněk Kocur, Ph.D., Machula, V.
  • Publikace: Proceedings of the 11th International Conference Knowledge in Telecommunication Technologies and Optics. Ostrava: VŠB - TUO, FEI, Katedra elektroniky a telekomunikační techniky, 2011. pp. 113-116. ISBN 978-80-248-2399-7.
  • Rok: 2011
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This article deals with the optimization of data transmission from the fast-moving objects, typically video signals from aerobatic aircraft. Optimization is performed on the second layer of the RM OSI and uses multiple transmission channels. The simulation was designed in network simulation tool OMNeT++ and is based on the wireless standard IEEE 802.11 (Wi-Fi). For simulation were created two cases using multiple transmission channels. These cases were compared with case of common wireless system which uses a single transmission channel. Proposed cases reached better error rates and proved their usefulness. They are also independent on the transmission technology (due to implementation on the second layer of RM OSI), therefore are versatile.

Telekomunikační sítě pro elektroenergetické systémy

  • Pracoviště: Katedra elektroenergetiky, Katedra telekomunikační techniky
  • Anotace:
    Kapitola popisuje telekomunikační sítě a jejich klíčové vlastnosti pro použití v elektroenergetice. Jsou ukázány vhodné telekomunikační struktury a topologie pro Smart grids. Rovněž jsou popsány příslučné standardy.

Aktuální stav projektu eduroam v ČR

  • Autoři: Ing. Zbyněk Kocur, Ph.D., Vacula, L., Machula, V.
  • Publikace: Elektrorevue. 2010, 13(2010/68), 68-1-68-7. ISSN 1213-1539.
  • Rok: 2010
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Tento článek popisuje základní rysy celosvětového akademického projektu eduroam. Čtenář je obeznámen nejen s jeho historií, ale i se současným stavem a jeho dalším vývojem na území ČR.

Analysis of Influence of Disturbance Level on Data Transmission in Wireless Networks

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This article is focused on the analysis of the interference effect in the Wireless Local Area Networks (WLAN). The aim of the article is to design concretely the methodology for the optimal wireless device configuration. The optimal parameters can be preciously suggested thanks to the methodology versatility for each of the wireless connection compatible with the IEEE 802.11 standard. The methodology is also applicable to other wireless technologies like IEEE 802.16, radio relay connections, optical links etc.

Analyzing of Data Flows at Czech Antarctic Station

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Paper deals with data transmission behind polar circle with respect to multimedia content and reliable data transport. Two different transmission algorithms are discussed in the paper. The first one is common periodic transfer used for transmission of collected data. The second one is transmission on demand trigged by scientists in Czech Republic.

Bezdrátový přenos dat na polárním kruhu

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Vědecké práce v odlehlých částech světa si žádají vhodně navržená komunikační řešení, která umožní splňovat požadavky kladené na konkrétní situaci. Antarktida je jedním z takových míst, které je výzvou pro návrh komunikačního zařízení jak z hlediska extrémních provozních podmínek, tak z hlediska omezených zdrojů energie.

Experimental Diagnostics of Impulse Noise

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The paper describes methodology of experimental diagnostics examining the influence of small home appliances in operation resulting in the injection of impulse noise into local communication lines.

Low Cost Network Emulator with Ethernet and E1 Interfaces

  • Pracoviště: Katedra telekomunikační techniky, Katedra počítačů
  • Anotace:
    Contemporary Next Generation Networks (NGN) are mainly built on the Internet Protocol (IP) and Ethernet. Major challenge for emerging types of wired and wireless IP-based networks is to provide an adequate Quality of Service (QoS) for different services. The quality of evaluation requires a detailed knowledge of the performance requirements for particular services and applications. The paper is primarily oriented to the end-to-end testing for the Ethernet-based terminal equipment. The extension for emulation network with the E1 interfaces and TDM over IP transmission can be used with external converters.

Možné způsoby přenosu audiovizuálních dat z akrobatických letadel

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Článek seznamuje s principy řešení bezdrátového přenosu digitálních toků z rychle se pohybujících objektů. Uvádí problémy spjaté s řešením a představuje konkrétní možnost realizace.

Nové možnosti experimentálního a výukového pracoviště bezdrátových přenosových systémů IEEE 802.11 a/b/g/n a IEEE 802.16-2004

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Článek představuje rozšířené možnosti inovovaného testovacího pracoviště, které na Katedře telekomunikační techniky slouží pro podporu výzkumu a výuky. Pracoviště slouží studentům i pro potřeby bakalářských a diplomových prací. Instalované bezdrátové technologie pracují v souladu se standardy IEEE 802.11a/b/g/n a IEEE 802.16-2004.

Optimization of compress algorithm in data satellite networks

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Satelite communication offers voice and data services. Two example designs of data transfer reduction are described. The first one illustrates IP optimization and the second one considers FTP optimization. Different compression methods and ciphering are considered.

Optimization of TCP Satellite Communication in Inmarsat Network

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The purpose of this paper is to present the improvements of packet data transmission via originally only voice oriented Inmarsat satellite network. The window size has been optimized to enable transferring files between the hosts in Inmarsat satellite network with increased throughput and also reduced transfer times.

Satelitní pracoviště sítě Inmarsat

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Článek se zabývá popisem nově vzniklého pracoviště satelitních technologií. V článku jsou popsány všechny klíčové součásti vybudovaného pracoviště. V první části je provedeno seznámení s použitou satelitní technologií společnosti Inmarsat, na které je celé pracoviště založeno. Další části se věnují popisu ovládání a diagnostiky všech klíčových prvků měřicího pracoviště. Poslední část je věnována aplikacím a úlohám určeným pro toto pracoviště.

The Use of Simulation Framework OMNeT++ in Telecommunications

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Simulation has ability to determine the system behavior without being put into operation, even without costly and time consuming production. Especially in the field of telecommunications, where it is often demanded to handle a huge number of messages or terminals, the possibility to test the system before the real deployment is strictly appropriate. Simulation framework OMNeT++ provides very good resources for fast design such as large-scale models. For example, the hierarchical approach to model, scalability, aptitude of detailed analysis and a large database of pre-built models of protocols.

Data Networks in the Area of Antarctic Circle

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Antarctica is an area without wired networks. The main instruments for data transfers are wireless networks, especially satellite ones. Their number is naturally limited. In the area of Antarctica there are special conditions such as yearlong low temperatures, limited power sources or period without human presence in the case of Czech base station. The scientists from all over the world try to research land, ice, different kinds of animals and plants, air or UV radiation. They naturally use a lot of kind of devices which help them in their research. The paper describes communication system which ensures yearly data transfer from Antarctica to Czech Republic respectively Internet.

Data Transfer Optimalization via Inmarsat Satellite Network

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The scientists from Czech Republic have started their research in Antarctica in 1927 and it continues up to the present day. In 2007 the first Czech polar base became operational. It is called Czech Mendel's Antarctic Base on James Rosse Island. The scientists use voice and data services. Voice communication is realized via Iridium satellite network. Data services require higher bit rates, which are offered by Inmarsat satellite network. The price for these services depends on specific terminal features and quantity of transferred data. Two example designs are included in order to demonstrate data transfer optimalization. The first one is focused on data IP optimization and the second one considers FTP optimization. Different compression methods and ciphering are considered.

Datové přenosy u polárního kruhu

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    V článku je popsán návrh a realizace komunikačního systému pro antarktickou polární stanici. Článek rovněž popisuje kroky, které bylo nutné učinit pro to, aby mohlo zařízení fungovat ve velmi nehostinných podmínkách, které u polárního kruhu panují.

Enhancement Ethernet Network Emulator

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The paper is primarily oriented to end-to-end testing for Ethernet based terminal equipments. The low cost Ethernet network emulator was developed on the Telecommunication Technology Department of the Faculty of Electrical Engineering of the Czech Technical University in Prague.

Laboratorní úlohy pro měření optických a metalických sítí

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    V rámci modernizace předmětu Základní měření ve sdělovací technice X37MST bylo vytvořeno několik laboratorních úloh zaměřených na problematiku datových sítí a přenosu dat. Studenti mají ve všech úlohách za úkol seznámit se s možnostmi analýzy optických a metalických datových sítí založených na technologii Ethernet.

Prioritization of Data Communications in Wireless and Switched Networks

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    A workplace for education and testing of prioritization in data communication over wireless and switched networks based on Ethernet and TCP/IP has been designed and implemented at the Department of Telecommunication Engineering. In its current configuration the workplace offers objective comparing of Quality of Service implementation in wireless networks based on 802.11 standard with support for IEEE 802.11e and in WiMAX according to IEEE 802.16-2004 standard. The design of the workplace enables easy supplementing of other transmission technologies and networking protocols. This paper describes the workplace, providing also necessary relations with IP and Ethernet.

Projekt eduroam na ČVUT

  • Autoři: Ing. Zbyněk Kocur, Ph.D., Vacula, L.
  • Publikace: International Workshop wRTT 2009. Praha: České vysoké učení technické v Praze, 2009. pp. 0068_0041. ISBN 978-80-01-04411-7.
  • Rok: 2009
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Tento příspěvek popisuje základní rysy projektu eduroam a shrnuje stav jeho řešení na půdě Českého vysokého učení technického v Praze. Čtenář je obeznámen se stavem implementace a principy funkce ověřování a mobility uživatelů. V závěru článku je nastíněn způsob implementace sítě eduroam do nových lokalit, zejména pak kolejí ČVUT.

Time Synchronization through Network Time Protocol and Improvement of Its Accuracy

  • Autoři: Pravda, M., Ing. Zbyněk Kocur, Ph.D.,
  • Publikace: TSP - 32nd International Conference on Telecommunications and Signal Processing. Budapest: Asszisztencia Szervező Kft., 2009. ISBN 978-963-06-7716-5.
  • Rok: 2009
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This paper deals with a packet network synchronization. Source of precise time is required in many devices. The basic intent of this work is to concentrate on improving the Network Time Protocol synchronization performance. That is why several algorithms were proposed and compared. The experiment results show that NTP can reach +- 5 microseconds accuracy of synchronization, but PTP is still more precise.

Transmission Methods for Multi-point Radio Link

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    In 2006, the project -Research and development the multipoint microwave systems- was initiated with support of the Ministry of Industry and Trade. Team from the Department of Telecommunications Engineering FEE, Czech Technical University in Prague participates in the project with main SVM Microwaves Ltd. The project is an industrial research in the field of microwave distribution systems, primary research and development of a new type of highspeed multipoint microwave links.

Advanced Transmission Methods for Multi-point Radio Link

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The basic intent of this paper is to present new possibilities in the high speed and robust communication in mobile wireless multi-point networks. It explains problems and its feasible solution concerning communication in movement.

Bezdrátové systémy v přístupové síti

  • Autoři: Ing. Zbyněk Kocur, Ph.D., Šafránek, M.
  • Publikace: Access server. 2008, 6(2008020002), 1-7. ISSN 1214-9675.
  • Rok: 2008
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Článek je úvodem do bezdrátových sítí založených na standardech známých pod označením Wi-Fi a WiMAX. Na něj budou navazovat další články obsahující řadu informací z oblasti aplikace, měření a dalšího vývoje těchto sítích vycházejících z experimentů a bohatých zkušeností autorů.

Experimentální a výukové pracoviště pro bezdrátové přenosové systémy

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Článek představuje testovací pracoviště vytvořené pro podporu výuky na Katedře telekomunikační techniky, které umožňuje studentům podrobné seznámení se s možnostmi systémů, které pracují v souladu se standardy IEEE 802.11a/b/g a IEEE 802.16-2004.

Fyzická vrstva Wi-Fi

  • Autoři: Ing. Zbyněk Kocur, Ph.D., Šafránek, M.
  • Publikace: Access server. 2008, 6.(2008050006), 1-6. ISSN 1214-9675.
  • Rok: 2008
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Článek je zaměřen především na fyzickou vrstvu standardu pro bezdrátové lokální sítě a osvětluje principy chování bezdrátových zařízení kompatibilních se standardem IEEE 802.11 na rádiovém rozhraní.

High Speed Mobile Communication

  • Autoři: Ing. Zbyněk Kocur, Ph.D., Šafránek, M.
  • Publikace: TSP - 31st International Conference Telecommunications and Signal Processing. Budapest: Asszisztencia Szervező Kft., 2008. ISBN 978-963-06-5487-6.
  • Rok: 2008
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The article is focused on problem and its feasible solution by use of very high speed wireless data transmission from quickly moving objects e. g. racing cars and planes to the ground. Research proceeded on the Department of Telecommunication Engineering at CTU in Prague in cooperation with Czech aerobatic pilots. The solution is designed for implementation in common wireless systems e.g. Wi-Fi and WiMAX. Research development and final measurement results are published in this article. The last part is focused on implementation of the solution to typical wireless data systems.

Satellite Data Transfer in the area of Antarctic Circle

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This article deals with the satellite communication system Inmarsat which was installed on the Czech Mendel's Antartic Base on James Rosse Island. The Inmarsat system (at least one part), was tested on the Department of Telecommunications Engineering at Czech Technical University in Prague. Some measurement results are published in this article. The last part is focused on those projects which are able to be resolved by means of this communication system.

Bezdrátové systémy v přístupové síti

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Bezdrátové systémy nabízejí elegantní, spolehlivé a relativně levné řešení vysokorychlostního datového připojení uživatelů k internetu. Daný článek se zaměřuje na technologie dle standardu IEEE 802.11 (Wi-Fi) a standardu IEEE 802.16 (WiMAX). Jsou popsány vlastnosti a základní principy používané v těchto technologií.

Měření v bezdrátových sítích

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Článek se zabývá popisem metody, kterou je možné použít pro měření bezdrátových sítí v reálných podmínkách. Tato metoda přehledně analyzuje všechny klíčové parametry přenosového řetězce. Díky časové souslednosti mezi testy na nižších a vyšších síťových vrstvách lze odhalit řadu skrytých problémů, které klasické testy odhalit nedokáží.

Za stránku zodpovídá: Ing. Mgr. Radovan Suk