AEEE. 2015, vol. 13

Permanent URI for this collectionhttp://hdl.handle.net/10084/111326

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Now showing 1 - 20 out of 75 results

Capacity of wavelength and time division multiplexing for quasi-distributed measurement using fiber bragg gratings
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Fajkus, Marcel; Navruz, Isa; Kepák, Stanislav; Davidson, Alan; Šiška, Petr; Čubík, Jakub; Vašinek, Vladimír
Signal conditioning in process of high speed imaging
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Hargaš, Libor; Koniar, Dušan; Simonová, Anna; Hrianka, Miroslav; Loncová, Zuzana
The accuracy of cinematic analysis with camera system depends on frame rate of used camera. Specific case of cinematic analysis is in medical research focusing on microscopic objects moving with high frequencies (cilia of respiratory epithelium). The signal acquired by high speed video acquisition system has very amount of data. This paper describes hardware parts, signal condition and software, which is used for image acquiring thru digital camera, intelligent illumination dimming hardware control and ROI statistic creation. All software parts are realized as virtual instruments.
Percolation phenomena for new magnetic composites and TIM nanocomposites materials
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Thabet, Ahmed
This paper presents a theoretical investigation in order to obtain new composite and nanocomposite magnetic industrial materials. The effective conductivity and thermal effective conductivity have been predicted by adding various types and percentages of conductive particles (Al2O3, MgO, ZnO, Graphite etc.) to the main matrices of Epoxy, Iron and Silicon for formulating new composite and nanocomposite industrial materials. The characterization of effective conductivity of new polymeric composites has been investigated with various applied forces, inclusion types and their concentrations. In addition, the effect of inclusion types and their concentrations on the effective thermal conductivities of thermal interface nanocomposite industrial materials has been explained and discussed.
Multiple transcoding impact on speech quality in ideal network conditions
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Mikulec, Martin; Fajkus, Marcel; Vozňák, Miroslav; Johansson, Olle
This paper deals with the impact of transcoding on the speech quality. We have focused mainly on the transcoding between codecs without the negative influence of the network parameters such as packet loss and delay. It has ensured objective and repeatable results from our measurement. The measurement was performed on the Transcoding Measuring System developed especially for this purpose. The system is based on the open source projects and is useful as a design tool for VoIP system administrators. The paper compares the most used codecs from the transcoding perspective. The multiple transcoding between G711, GSM and G729 codecs were performed and the speech quality of these calls was evaluated. The speech quality was measured by Perceptual Evaluation of Speech Quality method, which provides results in Mean Opinion Score used to describe the speech quality on a scale from 1 to 5. The obtained results indicate periodical speech quality degradation on every transcoding between two codecs.
Subjective video quality assessment of H.265 compression standard for full HD resolution
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Uhrina, Miroslav; Bienik, Juraj; Vaculík, Martin
Recently increasing interest in multimedia services leads to requirements for quality assessment, especially in the video domain. There are many factors that influence the video quality. Compression technology and transmission link imperfection can be considered as the main ones. This paper deals with the assessment of the impact of H.265/HEVC compression standard on the video quality using subjective metrics. The evaluation is done for two types of sequences with Full HD resolution depending on content. The paper is divided as follows. In the first part of the article, a short characteristic of the H.265/HEVC compression standard is written. In the second part, the subjective video quality methods used in our experiments are described. The last part of this article deals with the measurements and experimental results. They showed that quality of sequences coded between 5 and 7 Mbps is for observers sufficient, so there is no need for providers to use higher bitrates in streaming than this threshold. These results are part of a new model that is still being created and will be used for predicting the video quality in networks based on IP.
Synthesising TCP data traffic from industrial networks for simulations
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Hégr, Tomáš; Boháč, Leoš
In this paper, authors deal with a problem of an impaired TCP stream reconstruction from a real-world captured data. The goal is to obtain an original application data. The data are synthesized to be used as an input for a traffic generator. Authors describe a way to solve specific problems at transport and application layers during the reconstruction of an impaired TCP stream. The traffic reconstruction is oriented to IEC 60870-5-104 protocol on top of TCP. The evaluation of proposed algorithms shows that it is possible to estimate original time dependencies between received and dispatched messages with high accuracy.
CER/TER - the new metric for TCP connection robustness evaluation and comparison
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Vondrouš, Ondřej; Macejko, Peter; Kocur, Zbyněk
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.
Enhancing availability of services using software-defined networking
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Klepac, Martin; Hégr, Tomáš; Boháč, Leoš
The immense growth of client requirements imposed on data centre and cloud providers results in a conflict with traditional networking concepts lacking the required agility. In order to promote flexibility, which data centre providers promise to their clients, this discrepancy needs to be resolved, for instance by employing the novel concept of Software-Defined Networking (SDN). This paper utilises this concept in order to minimise service downtime while performing live virtual machine migration. The work is aimed at small/medium-sized data centres and hence the findings are based on real communication patterns found in such environments. Results show that packet loss is slightly diminished while available throughput is increased thanks to the proactive approach taken during network topology changes when compared to the traditional approach based on L2 forwarding.
FlowPing - the new tool for throughput and stress testing
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Vondrouš, Ondřej; Macejko, Peter; Kocur, Zbyněk
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.
Congestion aware multipath routing: performance improvements in core networks
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Kultan, Matej; Medvecký, Martin
In this paper the improved Congestion Aware Multipath Routing algorithm is analysed in terms of Core network throughput and longer paths contribution. The algorithm discovers unused network resources and dynamically adapts to the actual traffic load and available resources displacement. Several simulation scenarios have been benchmarked in order to verify algorithm in typical Internet Service Provider cases. Simulation scenarios in this paper are focused on verifying functionality in dense core networks. For this purpose, tests were performed on TeraStream based network â€“ the Deutsche Telekom Group design concept. Simulation results have proven better performance and resource utilization of the proposed algorithm than traditional Bellman-Ford based algorithms and equal cost multipath approaches.
RFID platform as a service, containerized ecosystem, feasibility and security impact analysis
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Kypus, Lukáš; Vojtěch, Lukáš; Neruda, Marek; Zitta, Tomáš
This paper presents a new concept as a special type of virtualization of particular event based communication components in RFID ecosystems. The new approach is containers based virtualization, and it is applied and tested on the container of Object name service. The results of the experiment allowed us to do the preliminary analysis of security consequences on the isolated containerized DNS-based RFID sub-service. We confirmed feasibility with this sandboxing technology represented by the special container. They bring the benefits in terms of efficient software component life-cycle management and integrity improvements. Experiments results of the containerization are discussed to show the possible isolation ways of other components like EPCis and middleware. There is present evaluation towards external threats and vulnerabilities. The result is a higher level of integrity, availability of whole ecosystem and resiliency against external threats. This gives a new opportunity to build robust RFID as Platform as a service, and it proves the ability to achieve a positive impact on the end to end service Quality of service.
Upper capacity bounds of MIMO wireless systems through fading channels
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Mahey, Rachna; Malhotra, Jyoteesh
This paper investigates the upper capacity bounds of MIMO systems with correlation and antenna selection techniques in general fading environments. With Antenna Selection techniques, the increased hardware complexity due to multiple antennas and large number of RF chains can be reduced to a substantial amount, retaining the diversity benefits of MIMO systems. The channel Correlation also affects the capacity of MIMO fading channels. Hence, to evaluate the upper bounds of capacity through fading channels, performance of MIMO systems is exemplified under Nakagami-m and Rayleigh fading channels while considering that the channel characteristics are known at a transmitter. The obtained results give an assessment to the better understanding to the effect of antenna selection and correlation on the capacity of MIMO channels, and how they can be used in different fading environments.
GNSS/RFID active transponder design
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Vojtěch, Lukáš; Skapa, Jiri; Bortel, Radoslav; Neruda, Marek; Hájek, Jiří; Lopour, Daniel
The paper describes a design of global navigation satellite system (GNSS)/Radio frequency identification (RFID) active transponder which is primarily designed for localization of objects as a part of localization system designated for efficient handling of situations with mass casualties. The precise localization is improved by differential GNSS. The block diagram of such GNSS/RFID active transponder is described including main operation procedures of the firmware. Measurement of the localization by algorithms of RTKLIB library and by algorithms of GNSS module is compared. Dynamic tests, i.e. GNSS/RFID active transponder placed in the moving car (50~kmph), and static tests, i.e. GNSS/RFID active transponder placed in the position for 15~min, are performed.
Overvoltage propagation from transmission line into transformer winding
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Kotlan, Václav; Benešová, Zdeňka
The paper deals with very fast transient phenomena in a system consisting of two parts: a cable line and a transformer winding. In this case an adequate model should be considered as a circuit with distributed parameters. Its description is given by a system of partial differential equations of hyperbolic type. Our approach is based on a numerical solution in the time domain and the method FDTD has been used. It allows obtaining results in a form of time-space voltage and current wave distribution along the cable line and the transformer winding. This distribution is depending on many factors some of them were studied in this paper.
Determining the level of global solar radiation on the earth's surface
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Dostál, Zdeněk; Ďulík, Miroslav
The article analyzes the Earth's surface insolation. For the analysis, two methods are described - the method of approximate calculation and turbidity method using Linke turbidity index. The methods consider the latitude of current location on the Earth's surface, atmosphere attenuation and other major factors. To obtain more accurate values, long-term measurements at the current location should be obtained.
The choice of numerical integration methods for the subsystems with the distributed parameters
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Rendzinyak, Serhiy; Korud, Vasyl
This article deals with methods of numerical modeling of heterogeneous electric circuits with distributed parameters for their possible use in the method of partitioning integration. We propose the use of modified Lax (LW) method for calculating the state of components with distributed parameters at the transient simulation in high-Q electric circuits, for example a transmission line. A comparison of transient simulation results in such circuits with the simulation results by known software systems is presented.
Primal domain decomposition method with direct and iterative solver for circuit-field-torque coupled parallel finite element method to electric machine modelling
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Marcsa, Daniel; Kuczmann, Miklos
The analysis and design of electromechanical devices involve the solution of large sparse linear systems, and require therefore high performance algorithms. In this paper, the primal Domain Decomposition Method (DDM) with parallel forward-backward and with parallel Preconditioned Conjugate Gradient (PCG) solvers are introduced in two-dimensional parallel time-stepping finite element formulation to analyze rotating machine considering the electromagnetic field, external circuit and rotor movement. The proposed parallel direct and the iterative solver with two preconditioners are analyzed concerning its computational efficiency and number of iterations of the solver with different preconditioners. Simulation results of a rotating machine is also presented.
Measured and simulated distributions of voltage and temperature along stator coils of synchronous generator
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Kacerovský, Jan; Krpal, Ondřej; Mach, František
The ECP (end winding corona protection) of the armature coils of a synchronous generator is designed and modeled. The paper focuses on the distribution of voltage and temperature along this protection that is both measured and simulated. The results are compared. The aim of the work is to verify the suggested mathematical model which would help to save time and costs connected with the ECP design.
Models of reliability prediction of electric machine taking into account the state of major structural units
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Zagirnyak, Mykhaylo; Prus, Viacheslav; Somka, Oleksandr; Doležel, Ivo
It is shown that conventional mathematical models for calculation of the reliability of electric machine structural units, based on the theory of planning an experiment, do not take into account the peculiarities of their properties variation during the process of manufacture and long-term operation. Taking into consideration the multiple factors of the assigned problem, the prospect of the use of fuzzy logic postulates in the creation of models for calculation of reliability is substantiated. An approach to such models building is formed.
Research related electromechanical processes in an asynchronous traction motor - asynchronous generator with common shaft based on field model
(Vysoká škola báňská - Technická univerzita Ostrava, 2015) Kazakov, Jurij; Palilov, Ilya
Creating energy efficiency traction induction motors with frequency control for hybrid drive vehicles defines practical interest for new methods of testing and simulation. Tests of these machines, it is desirable to carry out with energy recovery in the motor-generator, where a common shaft unites the machines. At present, the system simulation of motor-generator is carried out on simplified models without saturation, surface effect, jagged cores, and non-sinusoidal voltage of frequency converters. A refined interrelated mathematical model of asynchronous motor and generator operating with a common shaft, based on the theory of electrical circuits and field theory. Models allow the related modelling and study of static and dynamic modes electrical machines taking into account the saturation, skin effect, toothed cores, non-sinusoidal voltage of the frequency inverter, and variation parameters of the windings.

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