AEEE. 2014, vol. 12

Permanent URI for this collectionhttp://hdl.handle.net/10084/101666

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Now showing 1 - 20 out of 75 results

AFM imaging of natural optical structures
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Dallaeva, Dinara; Ramazanov, Shikhgasan; Prokopyeva, Elena; Kaspar, Pavel; Tománek, Pavel
The research in this field is focused to the investigation of biological structures with superior optical features. The study presents atomic force microscopy of biological optical structures on butterfly wings. The bright blue and dark black color scales exhibit the different topography. These scales were compared to the visually the same color scales of other two species of butterflies. The histograms of heights distribution are presented and show similar results for the scales of one color for different species.
Influence of surface roughness on optical characteristics of multilayer solar cells
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Scholtz, Ľubomír; Ladányi, Libor; Müllerová, Jarmila
Increasing efficiency of solar cells is still a discussed problem. Even if it is well-known that specially formed substrates as Asahi U-type for solar cells are produced, there is still a continuing attention given to the applications of surface roughness to achieve better light trapping and absorptance in solar cells. It was found out the even an exact interface morphology can play an important role in light trapping. In this paper we focused on the issue how final absorptance of a solar cell structure could be affected and possibly increased. The goal of this article is to show which of interfaces has the greatest influence on specular absorptance of the whole structure.
Software design of SMD LEDs for homogeneous distribution of irradiation in the model of dark room
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Liner, Andrej; Papeš, Martin; Jaroš, Jakub; Perecár, František; Hájek, Lukáš; Látal, Jan; Koudelka, Petr; Vašinek, Vladimír
This article describes wireless optical data networks using visible spectra of optical radiation with a focus on interior areas with direct line of sight LOS (line-of-sight). This type of network represents progressively evolving area of information technologies. Development of lightning technologies based on white power LED was the impulse for wireless optical data networks based on visible spectra of optical radiation (VLC) development. Its basic advantage is the flexibility of users. Users don’t have to stay on one place during the data sharing anymore. Wireless optical data networks represent an alternative solution for metallic and fiber networks [1], [2]. This paper deals with the software simulation of homogeneous distribution of optical irradiation in dark room model, carrying out in LightTools software. First, in previous simulations, the optical source composed from 9 SMD LED’s type LW G6SP-EAFA-JKQL-1 was designed. In various simulations, various numbers and distributions of LED’s were used. These were placed at the ceiling of the dark room. At last, the results of optical irradiation homogeneity are compared.
VLC transmitter with plastic optical fibers for indoor free space optic networks
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Vitásek, Jan; Šiška, Petr; Kepák, Stanislav; Čubík, Jakub; Pobořil, Radek; Látal, Jan
This article deals with the construction design of optical transmitter for indoor Free Space Optic (FSO) networks. This optical transmitter will be able to provide the lighting and communication at the same time. Thanks to special solution in spectral characteristic of transmitted light it is necessary to use two LEDs radiation sources. The light beams of these LEDs have to be spatially overlapped in crisscross direction and then the transmitter can realize both functions. There is described a construction of optical transmitter with plastic optical fibers which merges two LED beams together and provide lighting and communication at the same time.
Design, simulation and testing of the OOK NRZ modulation format for free space optic communication in a simulation box
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Vanderka, Aleš; Hájek, Lukáš; Látal, Jan; Vitásek, Jan; Koudelka, Petr
This article deals with the construction of a modulator and demodulator for Free-Space Optical (FSO) communication. In FSO optics, the modulated optical signal is propagated in the constantly changing environment (atmosphere). The optical signal is strongly influenced by the actual composition of air, which is directly linked to the change in refractive index in the turbulent cells. This article examines primarily the appropriate modulation format for FSO. For this purpose, one type of an OOK-NRZ modulator and one type of a demodulator were designed. This article also describes the construction of two types of photo detectors (the high impedance and the transimpedance ones). All electronic constructions were tested in the MicroCap simulator and they were experimentally measured as well. For the OOK NRZ modulation the, maximum transmission speed achieved the value of 160~Mbps. Measuring the quality of the modulation formats was carried out under mechanical and thermal turbulences. The last part of this work gives the results of the measurements of fog influences.
A practical approach to improve optical channel utilization period for hybrid FSO/RF systems
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Akbulut, Ahmet
In hybrid FSO/RF systems, mostly a hard switching mechanism is preferred in case of the FSO signal level falls below to the predefined threshold. In this work, a computationally simple approach is proposed to increase the utilization of the FSO channels bandwidth advantage. For the channel, clear air conditions have been supposed with the atmospheric turbulence. In this approach, FSO bit rate is adaptively changed to achieve desired BER performance. An IM/DD modulation, OOK (NRZ format) has been used to show the benefit of the proposed method. Furthermore, to be more realistic with respect to the atmospheric turbulence variations within a day, some experimental observations have been followed up.
Has silicon reached its limit?
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Davidson, Alan John Charles; Glesk, Ivan; Buis, Arjan
In light of the rapidly increasing demand for ultra-high speed data transmission, data centres are under pressure to provide ever increasing data transmission through their networks and at the same time improve the quality of data handling in terms of reduced latency, increased scalability and improved channel speed for users. However as data rates increase, present electronic switching technology using current data centre architecture is becoming increasingly difficult to scale despite improvements in data management. In this paper the tremendous bandwidth potential of optical fibre based networks will be explored alongside the issues of electronic scalability and switching speed. A resulting need for alternative optical solutions for all-optical signal processing systems will be discussed. With this in mind, progress in the form of a novel and highly scalable optical interconnect will be reviewed.
Tm-Yb doped optical fiber performance with variation of host-glass composition
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Dhar, Anirban; Pal, Atasi; Das, Shyamal; Sen, Ranjan
The fabrication process of Thulium-Ytterbium doped optical fiber comprising different host glass through the Modified Chemical Vapor Deposition (MCVD) coupled with solution doping technique is presented. The material and optical performance of different fibers are compared with special emphasis on their lasing efficiency for 2 µm application.
The analysis of fiber sensor of temperature field disturbance by human body part access
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Dvořák, Filip; Maschke, Jan; Vlček, Čestmír
The principle of this sensor function is based on polarization maintaining fiber (PMF) sensitivity during excitation of both two polarization modes. This excitation is caused by temperature change, when absorbing thermal radiation. This mechanism is used for detection of temperature field disturbance as an indicator. In the case described below, attention was devoted to temperature field disturbance on a part of the human body. Thus this sensor system could be used for protection of some entity. The aim of this study was to determine the sensitivity of PMF to radiating heat, the space configuration and time response.
Active optical fibers doped with ceramic nanocrystals
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Mrázek, Jan; Kašík, Ivan; Procházková, Lenka; Čuba, Václav; Aubrecht, Jan; Cajzl, Jakub; Podrazký, Ondřej; Peterka, Pavel; Nikl, Martin
Erbium-doped active optical fiber was successfully prepared by incorporation of ceramic nanocrystals inside a core of optical fiber. Modified chemical vapor deposition was combined with solution-doping approach to preparing preform. Instead of inorganic salts erbium-doped yttrium-aluminium garnet nanocrystals were used in the solution-doping process. Prepared preform was drawn into single-mode optical fiber with a numerical aperture 0.167. Optical and luminescence properties of the fiber were analyzed. Lasing ability of prepared fiber was proofed in a fiber-ring set-up. Optimal laser properties were achieved for a fiber length of 20~m. The slope efficiency of the fiber-laser was about 15%. Presented method can be simply extended to the deposition of other ceramic nanomaterials.
Measuring optimal length of the amplifying fiber in different working conditions of the amplifier
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Pobořil, Radek; Šiška, Petr; Látal, Jan; Čubík, Jakub; Smrž, Martin; Kepák, Stanislav; Vašinek, Vladimír
The aim of this article is to highlight possible unwanted behaviour of an EDFA optical amplifier during temperature changes. After a brief introduction dealing with amplifiers and doped fibers in general we focus on the assembly of our own EDFA amplifier with standard construction and the IsoGain I-6 amplifying fiber, and on the parameters of its individual components. Since an erbium doped fiber has usually no direct thermal stabilization, temperature changes can affect performance of the entire amplifier. The next part of the article therefore describes the impacts of such changes on behaviour of our amplifier. At the very end we performed a measurement of the amplifier deployed in the actual WDM-PON the description of which can be found in the last chapter.
Similarity analysis of EEG data based on self organizing map neural network
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Jahan, Ibrahim Salem; Prilepok, Michal; Snášel, Václav; Penhaker, Marek
The Electroencephalography (EEG) is the recording of electrical activity along the scalp. This recorded data are very complex. EEG has a big role in several applications such as in the diagnosis of human brain diseases and epilepsy. Also, we can use the EEG signals to control an external device via Brain Computer Interface (BCI) by our mind. There are many algorithms to analyse the recorded EEG data, but it still remains one of the big challenges in the world. In this article, we extended our previous proposed method. Our extended method uses Self-organizing Map (SOM) as an EEG data classifier. The proposed method we can divide in following steps: capturing EEG raw data from the sensors, applying filters on this data, we will use the frequencies in the range from 0.5~Hz to 60~Hz, smoothing the data with 15-th order of Polynomial Curve Fitting, converting filtered data into text using Turtle Graphic, Lempel-Ziv complexity for measuring similarity between two EEG data trials and Self-Organizing Map Neural Network as a final classifiers. The experiment results show that our model is able to detect up to 96% finger movements correctly.
Thermal experimental dielectric characterization of cost-fewer low-density polyethylene nanocomposites
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Gouda, Osama; Thabet Mohamed, Ahmed
Polymer properties can be experimentally tailored by adding small amounts of different fillers, but they are expensive with respect to the classical polymer materials. This paper has been studied the enhancement and controlling of electric and dielectric properties of low-density polyethylene (LDPE) polymer materials by cost-fewer nanoparticles. Certain percentages of clay and fumed silica nanoparticles have been enhanced electric and dielectric properties of low-density polyethylene nanocomposite. Dielectric spectroscopy has been measured the electric and dielectric properties of low-density polyethylene with and without nanofillers at various frequencies (10Hz-100kHz) and temperatures (20°C, 40°C and 60°C). Also, it has been investigated the optimum percentages of nanofillers with respect to nanofillers type, filler concentration and temperature for enhancing electric and dielectric characterization of low-density polyethylene. Experimental measurements have been carried out on dielectric breakdown strength of new polyethylene nanocomposites materials under variant electric fields (uniform, and non-uniform) and variant temperatures. It has been specified the effective nanofillers factors on dielectric breakdown strength of polyethylene nanocomposites materials.
The derivation of the electrical conductance/temperature dependency for tin dioxide gas sensor
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Gajdošík, Libor
The dependency between the electrical conductivity and the temperature of the tin dioxide layer at the constant concentration of the detected gas is derived here. The derived equation is modified as a function of two variables describing the dependence of the electrical conductivity of the sensor on both the temperature and the concentration. The derived formulas were verified by approximation of the measured data. These formulas can be useful in practical applications.
An experimental study of laboratory hybrid power system with the hydrogen technologies
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Minařík, Daniel; Horák, Bohumil; Moldřík, Petr; Slanina, Zdeněk
This paper presents very small laboratory hybrid photovoltaic-hydrogen power system. The system was primarily assembled to verify the operability of the control algorithms and practical deployment of available commercial hydrogen technologies that are directly usable for storage of electricity produced from renewable energy sources in a small island system. This energetic system was installed and tested in Laboratory of fuel cells that is located in the university campus of VSB-Technical University of Ostrava. The energetic system consists of several basic components: a photovoltaic field, accumulators bank, water commercial electrolyzer and compact fuel cell system. The weather conditions recorded in two different weeks as model weather and solar conditions are used as case studies to test the energetic system and the results for two different cases are compared each other. The results show and illustrate selected behaviour curves of the power system and also average energy storage efficiency for accumulation subsystem based on hydrogen technologies or at the energetic system embedded components. On the basis of real measurement and its evaluation the ideal parameters of the photovoltaic field were calculated as well as the hydrogen technologies for supposed purpose and the power requirements.
On multidimensional linear modelling including real uncertainty
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Nowaková, Jana; Pokorný, Miroslav
The theoretical background for abstract formalization of vague phenomenon of complex systems is fuzzy set theory. In the paper are defined vague data as specialized fuzzy sets - fuzzy numbers and there is described a fuzzy linear regression model as a fuzzy function with fuzzy numbers as vague regression parameters. To identify the fuzzy coefficients of model the genetic algorithm is used. The linear approximation of vague function together with its possibility area are analytically and graphically expressed. The suitable numerical experiments are performed namely in the task of two-dimensional fuzzy function modelling and the time series fuzzy regression analysis as well.
Model-based attitude estimation for multicopters
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Baránek, Radek; Šolc, František
The paper deals with model-based attitude estimation for multicopters and is mainly focused on investigation of accuracy degradation due to wind and inaccurate model parameters which are conditions always present when using in real world. At first the need for model-base estimation is motivated. Then the multicopter model is described. Based on the mathematical model of multicopter, the estimation algorithm utilizing the extended Kalman filter is constructed. The main contribution of the paper is the investigation of the negative impact of the wind and of inaccurate knowledge of the model parameters.
Control design of mixed sensitivity problem for educational model of helicopter
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Ožana, Štěpán; Vojčinák, Petr; Pieš, Martin; Hájovský, Radovan
The paper deals with the design of H-∞ robust controller, particularly with mixed sensitivity problem for elevation control. It briefly introduces basic mathematical background concerning robust control approach, which is then applied for typical example of MIMO system, that is a helicopter model. The obtained results are verified on real educational physical model CE 150 by Humusoft, ltd.
Novel 3D modelling system capturing objects with sub-millimetre resolution
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Chromý, Adam; Žalud, Luděk
This paper presents novel 3D modelling system providing three-dimensional shaded models of objects, with representing brightness and smoothness of it's surface. Proposed device is based on laser scanner and robotic manipulator, which empowers high flexibility since it is programmable in 6 degrees of freedom. Exchangeable laser scanners empower capability of building models of both tiny detailed structures and large object. Device is primarily intended to use at health care domain, where it brings lot of expenses savings compared to presently used scanning systems, but it could be used in many other applications. Scanning system constitution, operation and parameters are discussed.
A man as the regulator in man-machine systems
(Vysoká škola báňská - Technická univerzita Ostrava, 2014) Havlíková, Marie; Šedivá, Soňa; Bradáč, Zdeněk; Jirgl, Miroslav
The aim of the paper is to present the role of the human element in regularly used man-machine systems (MMS). From the technical point of view, it is possible to denote the human being and the machine as two components of one system. In the second part of the article, the authors introduce the results obtained through simulations of the human driver model; these simulations are focused on the quality of the control process. The structure of the model facilitates the detection and analysis of human error identifiers.

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