AEEE. 2020, vol. 18

Permanent URI for this collectionhttp://hdl.handle.net/10084/139125

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Now showing 1 - 20 out of 30 results

Color Content Descriptors of Images by Vector Quantization
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Mihálik, Jan; Gladišová, Iveta
In the paper, we propose color content descriptors of images by vector quantization in RGB color space compared to scalar ones. In order to obtain a much more accurate discrete representation of this space we use our algorithm for optimization of vector quantizers. We introduce several modifications of these descriptors such as global, structural as well as of dominant color. We consider a different number of bins and evaluated the similarity of the color content of images using mean square error of color histograms of a reference image and a searched image. Then, the color content of the image with the minimum error was the most similar to the reference image. We also used a parameter of variance, if the color content of several searched images was very similar based on the mean quadratic error for the structural descriptor. By vector quantization of RGB space we can achieve 2–3 times decreasing the number of bins at the same accuracy.
Footer Voltage Controlled Dual Keeper Domino Logic with Static Switching Approach
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Parashar, Chirag; Trivedi, Avijeet Kumar; Agarwal, Aman; Pandey, Neeta
In this paper, two circuits, namely Footer Voltage Controlled Dual Keeper domino logic (FVCDK) and Footer Voltage Controlled Dual Keeper with Static Switching domino logic (FVCDK-SS) are presented, in order to achieve high speed, low power consumption and robustness. The dual keeper arrangement helps in reducing the loop gain of the feedback circuitry, which leads to lower delay variability. The keeper circuitry is controlled using the footer voltage to reduce the contention current in the initial evaluation phase, and thus providing enhanced speed. In FVCDKSS domino logic, unwanted transients at the output are reduced by incorporating pseudo-dynamic buffer in the proposed FVCDK domino logic. This further reduces the dynamic power consumption. The results of the logic presented here are validated by comparing them to a wide range of existing domino logic circuits for a variety of performance metrics such as delay, power, power-delay product and unity noise gain. To effectively gauge the wide fan-in capabilities of the proposed logic, results are shown for the various fan-in OR gate. The simulations of the circuits are carried out using industry standard full-suite Cadence tools using 45 nm technology library.
A Transconductance-Mode Multifunction Filter with High Input and High Output Impedance Nodes Using Voltage Differencing Current Conveyors (VDCCs)
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Siripruchyanun, Montree; Jaikla, Wina
The design of transconductance-mode multifunction biquad filter containing three input voltage nodes and single-output current node is proposed. Its circuit principle is emphasized on employing Voltage Differencing Current Conveyor (VDCC) to be an active building block. The proposed filter description uses three VDCCs co-working with two grounded capacitors and three grounded resistors. The synthesis of the proposed multifunction filter is based on avoidance of using multiple-output active elements to achieve commercially available integrated circuits for practical implementation. Additionally, without multiple-output active element, it can alleviate current tracking error from the current mirrors used in output ports. It also decreases the amounts of the transistors inside the active elements. The proposed multifunction filter offers all 5 filter functions, which are non-inverting Low-Pass (LP), non-inverting High-Pass (HP), non-inverting Band-Pass (BP), non-inverting Band-Reject (BR) and also non-inverting All-Pass (AP) functions from same circuit topology under different circuit condition for input signals. Furthermore, the natural frequency for all filtering responses is independently achieved from the bandwidth or the quality factor of the proposed filter. For cascade-able connectivity, the output current port indeed provides a high impedance. In addition, the magnitude of the output current for all filtering functions can be resistively adjusted. The consideration for non-ideal case of the presented multifunction filter is also analyzed. The simulation and experimental results of the presented transconductance multifunction biquad filter based on VDCC practically implemented by the commercially available ICs, LM13700 and AD844 can validate the theoretical anticipation.
Non-Intrusive Parametric Audio Quality Estimation Models for Broadcasting Systems and Web-Casting Applications Based on Random Forest
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Jakubík, Martin; Počta, Peter
Objective quality assessment models have been used more and more in recent years to assess or monitor speech and audio quality in many multimedia and audio processing systems. These methods offer a clear and repeatable way to evaluate a customer experience by measuring perceived quality on a subjective scale, which is easily understood, such as a quality rating scale, ranging from excellent quality to a low quality. Subsequently, the aim of service providers is to offer reliable services providing the end-user/customer with the best possible quality in the context of the current network conditions to avoid a customer churn. This paper presents a design and performance evaluation of parametric models estimating the audio quality experienced by the end user of broadcasting systems and web-casting applications. The Random Forest (RF) algorithm is used to design non-intrusive parametric models, establishing the relationship between the feature description and the perceived quality scores. For this, the broadcast and web-cast sub-databases were created, where the web-cast sub-database includes 17,280 degraded samples and the broadcast sub-database contains 1,080 degraded samples obtained from the Slovak Radio. The results reported for the proposed parametric audio quality models have validated Random Forest as a powerful technique that provides a good efficiency in terms of Pearson Correlation Coefficient (PCC) and Root Mean Squared Error (RMSE).
Performance Analysis of Downlink Non-Orthogonal Multiple Access under Imperfect CSI in Dense Network: A Stochastic Geometry Approach
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Nguyen, Thanh-Luan; Do, Dinh-Thuan
A single-tier downlink Non-Orthogonal Multiple Access (NOMA) network is considered in this paper where analytical framework is given for performance evaluation. Particularly, the outage probability at the downlink users is studied under the impact of imperfect Channel State Information (CSI). The intercell interference and the intra-cell interference are also taken into consideration to capture practical behaviors of the proposed system. Further, we also adopt the Poisson Point Process (PPP) to model the location of the base stations and the downlink users in this work. For the imperfect CSI scenario, the results point out that the more times the user spends on performing interference cancellation, the more severe the user is affected by channel estimation error and vice versa. The results for the outage probability expressed in the analytical-forms are then confirmed by the Monte Carlo simulations.
DG Allocation in Distribution Networks with Considering of Voltage Stability Improvement and Loss Reduction
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Kazeminejad, Mohammad; Banejad, Mahd
The improvement of the line Load-ability (LL) for voltage stability establishes the main criterion for distribution networks. The Distributed Generation (DG) resources play an important role in the supply of active and reactive power loads, bus voltage profiles, and voltage stability in distribution systems. In this paper, a new technique has been proposed for optimization of the location placement and sizing of DGs, considering the Generalized voltage Stability Index (GSI) to determine the maximum load-ability. Also, an analytical method has been applied to infer the effects of DGs on the distribution systems’ characteristics. The study also considers three types of DG modes, which are voltage control mode (PV mode), constant power mode (PQ mode), and also voltage control mode with reactive power constraint (PV mode with VAR constraint). The proposed method is applied to 12-bus, modified 12-bus, 69-bus and 94-bus radial distribution systems.
Comparison of Trapezoidal and Sinusoidal PWM Techniques for Speed and Position Control of PMSM
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Bekiroglu, Erdal; Dalkin, Ahmet
In this article, speed and position controls of Permanent Magnet Synchronous Motor (PMSM) are performed by using a genetic algorithm-based controller. Hall Effect sensors have been used to obtain position data of the motor. Since Hall Effect sensors have been mounted, PMSM has been driven as a Brushless DC (BLDC) motor. Sinusoidal and trapezoidal current reference models have been used in the control system. The proposed control system has been operated for speed control as well as position control of the motor. The developed genetic-based speed and position control method has been tested for both trapezoidal and sinusoidal PWM commutation techniques. The results obtained from these commutation techniques have been compared. Speed and position results of the motor have been obtained under the different load and operating conditions. The results reveal that the proposed control system is reliable, robust and effective.
Ensemble feature selection approach based on feature ranking for rice seed images classification
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Tuan, Dzi Lam Tran; Surinwarangkoon, Thongchai; Meethongjan, Kittikhun; Hoang, Vinh Truong
In smart agriculture, rice variety inspection systems based on computer vision need to be used for recognizing rice seeds instead of using technical experts. In this paper, we have investigated three types of local descriptors, such as Local Binary Pattern (LBP), Histogram of Oriented Gradients (HOG) and GIST to characterize rice seed images. However, this approach raises the curse of dimensionality phenomenon and needs to select the relevant features for a compact and better representation model. A new ensemble feature selection is proposed to represent all useful information collected from different single feature selection methods. The experimental results have shown the efficiency of our proposed method in terms of accuracy.
Forecasting of Energy Consumption and Production Using Recurrent Neural Networks
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Shabbir, Noman; Kutt, Lauri; Jawad, Muhammad; Iqbal, Muhammad Naweed; Ghahfaroki, Payam Shams
Energy forecasting for both consumption and production is a challenging task as it involves many variable factors. It is necessary to calculate the actual production of energy and its consumption as it is very beneficial in maintaining demand and supply. The reliability and smooth functioning of any electrical system are dependent on this management. In this article, the Recurrent Neural Network (RNN) based algorithm is used for energy forecasting. The algorithm is used for making three days ahead prediction of energy for both generation and consumption in Estonia. A comparison is also made between our proposed algorithm and the forecasting algorithm used by Estonian energy regulatory authority. The results of both algorithms indicate that our proposed algorithm has lower Root Mean Square Error (RMSE) and is giving better forecasting.
Improved Transformer Differential Protection by Adaptive Pickup Setting during Momentary Over-Fluxing Condition
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Raichura, Maulik; Chothani, Nilesh; Patel, Dharmesh
The differential relaying scheme is universally adopted as the main protection for power transformer. In certain situations, like temporary over-fluxing, this differential protection may malfunction. This is due to unbalance in primary and secondary current, as the saturated core does not reflect equal ampere-turn on either side. This article presents detection of over-fluxing condition against the internal fault based on the fifth harmonic component of differential current. As per the estimated level of the fifth harmonic concerning the fundamental component of differential current, the pickup setting of percentage bias characteristic will be modified to avoid maloperation. Once the over-flux condition is sensed, the algorithm activates timer-based V/f protection to protect the equipment. The proposed algorithm is validated on PSCAD software and after the collection of data, MATLAB software is used for further validation. The proposed algorithm is validated under various test conditions like normal load, external fault, internal fault, and over-fluxing. It is observed that the algorithm accurately detects internal fault in the transformer or blocks the relay operation under momentary over-fluxing situations. Further, to assassinate the competency of the proposed scheme, a practical test is performed on a single-phase transformer available in laboratory. The data for various test cases are captured with the help of DSO, and the collected data has been migrated to computer where the proposed algorithm is examined. After analyzing all the results, it is cleared that the proposed algorithm can prevent transformer isolation during momentary over-fluxing conditions.
Single-Phase PLL Based on an Adaptive Notch Filter
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Belandria, Luciano Emilio; Bergas, Joan
Single-Phase Phase-Locked Loops (PLL) have become a crucial component of grid-tied power converters. PLL accuracy and fast response are important for control and protection purposes, especially in the presence of voltage harmonics and frequency variations. In this paper, a new PLL structure based on an Adaptive Notch Filter (ANF) is presented. This ANF, which generates the orthogonal system of the PLL, is implemented with an All-Pass Filter (APF) having inherent advantages, such as low sensitivity to coefficient rounding when implemented in fixed-point microprocessors and easy implementation in a Digital Signal Processing (DSP). Both simulation with MATLAB/Simulink, and experimental results on a fixed-point DSP, are presented and analyzed to evaluate the performance of the introduced PLL and to support the theoretical development. A set of comparative simulations between the proposed PLL and a some single-phase PLL described in the literature are conducted to validate the method.
Power Losses Estimation for Visualization of Heat Distribution
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Rešutík, Patrik; Kaščák, Slavomír
For designing power electronics, especially high-power-density systems, power loss estimation is a very important step in the design process. The estimation of losses without using a mathematical method, but instead using a simulation approach can significantly lower design time. In this paper, the estimation of the power losses by the simulation method using MATLAB Simulink is presented. The main goal of this paper is the estimation of the worst-case scenario of the inverter losses powering the three-phase asynchronous motor. Simulation is using real parameters of the used semiconductors to accurately estimate power losses. The simulation model consists of two main parts. The first one calculates power losses in semiconductors based on the provided parameters and his temperature. The second part calculates the temperature of the system based on the cooling model and losses calculated by the first system. Results in the form of the losses are used in the Fusion 360 software to simulate the temperature distribution of the heatsink. This simulation is supported by the calculation of the convection coefficient of the heatsink in different airflows. Additionally, two types of heat transfer were simulated, convection only and convection plus radiation type of heat dissipation.
Nonlinear Observer Design for Load Torque Estimation of Induction Motors
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Vu, Giang Hoang; Yahoui, Hamed; Hammouri, Hassan
The paper introduces a design of a nonlinear observer for the estimation of load torque of induction motors based on the output of the stator currents. The observer is built in the synchronous reference frame d-q with three main steps. First, the nonlinear observer for the class of non-affine control systems is reviewed. Second, the induction motor model is written in an appropriate form as a non-affine control system with canonical form for the design of the nonlinear observer. The system state is composed of the stator currents, speed and load torque. Based on the stator currents, the rotor flux leakages are estimated via an open loop and used for the load torque observer. The observer is designed with a constant gain which is calculated by considering the trajectory of the rotor flux leakages. Both the load torque and rotor speed can be estimated by using the proposed observer. Finally, simulation and experiment are carried to validate the effectiveness and robustness of the proposed observer.
Efficiency Assessment of Induction Motors Drives Operating Under Shaft Misalignment Conditions
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Verucchi, Carlos Javier; Giraldo, Esteban; Meira, Matias; Ruschetti, Cristian Roberto; Bossio, Jose Maria; Bossio, Guillermo Ruben
Historically, the negative effects of misalignment between the motor shaft and the load on the electric drives are well known. Vibrations, loss of life of couplings and deterioration of efficiency are some of these effects. Regarding this last point, the literature offers contradictory opinions. Some studies consider that the loss of efficiency in cases of misalignment is undesirable; while others consider that it has significant importance. In this paper, experimental results show in which cases the misalignment has a significant effect on efficiency and in which cases it can be neglected. For this, radial and angular misalignment cases are studied with four of the most used flexible couplings in the industry. The obtained results are analysed in relation to the actual regulations on energy efficiency in induction motors. The reached conclusions offer new tools for the correct selection of flexible couplings tending to the improvement of energy efficiency.
Switching Losses Analysis of a Constructed Solar DC-DC Static Boost Converter
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) El Merrassi, Weam; Abounada, Abdelouahed; Ramzi, Mohamed
The DC-DC converter is majorly used in several renewable energy applications. It is usually relevant in a hard-switching operating mode at the cost of increasing power losses and declining efficiency. Power losses are comprised of switching losses and conduction losses, which affect the reliability and speed up the aging of the switch. Therefore, soft-switching techniques are inescapable to reduce electromagnetic interference EMI, minimize losses, and enhance power conversion efficiency. Among the sundry techniques of soft-switching, passive snubbers are uncomplicated and vigorous, besides it has been spotlighted as a finer alternative compared to the active snubbers that involve extra switches and an additional control circuit. This paper investigates the power loss of a conventional solar DC-DC static converter designed and controlled through Maximum Power Point Tracking (MPPT). It evaluates the switch's temperature in the hard-switching operating mode. Besides, this paper presents a new research initiative that aims to allow a zero switching and stabilizing the temperature of the switch through a novel approach of design for RLD and RCD snubber cells. This new design allows the switch to achieve soft-switching, by abolishing the voltage stress, minimizing the power losses, and stabilizing the junction temperature. This snubber has a simple structure with a few components and ease of control, which helps to upgrade the power conversion efficiency through controlling the high voltage and current stress in the switch. In this treatise, elements of the snubber are designed and adjusted for maximum reliability through the simulation in OrCAD environment. Furthermore, the effectiveness of the model is approved through experimental results on a 1600 W conventional boost to validate the proposal.
Comparative study of CFSI,Trans-CFSI and SL-QSBI
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Sharif, Muhammad Awais; Siddique, Muhammad; Mubasher, Muhammad; Iqbal, Danish; Hussain, Ghayyur; Imran, Muhammad Ali
This paper presents the comparative analysis of the three types of inverters which are Current-Fed Switched Inverter (CFSI), Trans- Current-Fed Switched Inverter (Trans-CFSI), and improved Switched Inductor-Quasi Switched Boosted Inverter (SL-QSBI). Also, a simple boost Pulse-Width- Modulation (PWM) Scheme is applied to CFSI, Trans- CFSI, and improved SL-QSBI. Each inverter category is analyzed separately for evaluating the effect of variation in duty ratio on the modulation index and boost factor. The comparisons of these inverters are rendered to quantify the voltage boost ability, voltage stress on the switching device and the voltage gain ability. Moreover, a simple boost control scheme is also modified to attain high modulation index. The efficacy of the proposed results is verified using the Saber software simulations.
Qualitative Assessment of the UV Exposition Process Near the Diffraction Limits
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Zawadzka, Agnieszka; Indykiewicz, Kornelia; Paszkiewicz, Regina
Optical lithography is one of the most common microfabrication methods. A major limitation of photolithography is a diffraction phenomenon, which affects the falsities in dimensions and shape of designed structures, due to the light bending on the mask edges. In the presented work, the technological parameters that influence the shape of the resist structures are reported. The experimental results are compared with the simulations results, based on the solution of Maxwell’s equations using the RF module of COMSOL Multiphysics software. The electric field intensity distribution in the resist layer was analysed for the mask slits that are larger and comparable to the applied wavelength. The differences in wave energy absorption in the resist layer are presented and discussed. For both cases, the impact of the chromium film thickness of the mask on the pattern profile of the resist is studied, and the comparison is performed between the simulation and experimental results.
Enhanced Luminous Efficacy of White LED with Flat Dual-Layer Remote Phosphor Structure
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) That, Phung Ton; Loan, Nguyen Thi Phuong; Anh, Nguyen Doan Quoc; Le, Anh-Tuan
This paper shows the differences in luminous fluxes of two distinguishing dual-layer remote phosphor structures, Flat Dual-Remote Phosphor (FDRP) and Concave Dual-Remote Phosphor (CDRP). The impact of the distance between the two phosphor layers (d1) and the distance from the phosphor layer to the LED surface (d2) on the optical properties of the CDRP is also presented. Specifically, when d1 and d2 are varied, the scattering and absorption characteristics of the remote phosphor layer change dramatically, which enormously influences the color uniformity and illumination capability of WLEDs. The concentration of YAG:Ce3+ phosphor also needs to be modified so that the correlated color temperature of WLEDs could be maintained at 8500 K when d1 and d2 are adjusted. In case d1 = d2 = 0, the scattering and absorption in the remote phosphor layer are minimal, leading to the infinitesimal color and luminous flux. When d1 and d2 get bigger, the scattering surface increases and that the blue and yellow rays are blended becomes more uniform, leading to the minimum white light deviation as well as the lowest luminous flux. According to the studied results, the lumen output can be maximum at 1020 lm if d1 = 0:08 mm or d2 = 0:63 mm while the smallest color deviation occurs when d1 = 0:64 mm or d2 = 1:35 mm. Therefore, the researched results will provide further information for choosing the suitable d1 and d2 in order to improve the quality of WLEDs.
Frequency Dependent Alterations of S. Cerevisiae Proliferation Due to LF EMF Exposure
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Radil, Roman; Barabáš, Ján; Janoušek, Ladislav; Bereta, Martin
The presented paper deals with low frequency electromagnetic field application on Saccharomyces cerevisiae cells. Experiments performed through wide frequency range have shown selective frequency dependent biological response, which could be successfully predicted by ion parametric resonance theory proposed by V. V. Lednev. Although observed results give satisfying answer to questions whether or not electromagnetic fields could affect cell cultures even at non-thermal levels, the research presented herein opens a multitude of questions about the exact physical mechanisms underlying the observed microorganism behavior, as the theory discussed within the scope of this article is still not completely unambiguous.
Concept of a Wearable Temperature Sensor for Intelligent Textile
(Vysoká škola báňská - Technická univerzita Ostrava, 2020) Hudec, Róbert; Matúška, Slavomír; Kamencay, Patrik; Hudecová, Lucia
This paper proposes the intelligent textile for human body temperature measurement. The main concept of the textile is based on two commercially available LM35DM temperature sensors, knitted electrically conductivity yarns and five areas for pressstud. Three different measurements methods were used in our experiment. Three measurements were performed in the first step, digital thermometer in person’s armpit, contact-less thermometer in the places close to our LM35DM sensors and contact-less thermometer on the forehead. Next, two LM35DM in SOIC8 package were used for temperature measurement within intelligent textile. Finally, the first step was repeated. All measurements were done on ten subjects with their permission to collect body temperature data for scientific purposes. The results show that the average measurement error for first sensor is 0.844 C and 0.278 C for second sensor.

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