SERBIAN JOURNAL OF ELECTRICAL ENGINEERING
Vol. 14, No. 2, June 2017
CONTENTS
A Multi-Layered Image Format for the Web with an Adaptive Layer Selection Algorithm
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DOI: https://doi.org/10.2298/SJEE161010001T
Abstract: In this paper we present a proposed multi-layered image format for use on the web. The format implements an algorithm for selecting adequate layer images depending on the image container's surroundings and size. The layer selection depends on the weighted average brightness of the underlying web page background within the bounds of the image. The proposed image format supports multiple image layers with adjoined thresholds and activation conditions. Depending on these conditions and the underlying background, a layer's visibility will be adequately set. The selection algorithm takes into account the background brightness, each layer's adjoined threshold values, and other newly introduced layer conditions.
Keywords: Image format, Layers, Selection algorithm, Web, Responsive design.
Optimization of Electric and Magnetic Field Emissions Produced by Independent Parallel Overhead Power Lines
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DOI: https://doi.org/10.2298/SJEE161115002R
Abstract: This paper presents a method for determining optimal arrangements of parallel independent overhead power lines aimed to decrease electric and magnetic field emissions. The Genetic Algorithm (GA) is used to find the optimal placement of conductors. The Monte Carlo approach implemented in GA allows consideration of uncertain phase shifts between independent overhead power lines. The results and practical aspects of the proposed methodology are illustrated on two different configurations of both independent 400 kV single-circuit and double-circuit overhead power lines.
Keywords: Magnetic field, Electric field, Phase shift, Genetic algorithm, Optimization.
Compact Microwave Triple-mode Bandpass Filter in Planar Technology
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DOI: https://doi.org/10.2298/SJEE170117003P
Abstract: This paper introduces a novel microwave planar filter design using triple – mode resonator. In order to achieve the filter size reduction we use the multilayer technology. The structure consists of two dielectric layers separated by a common ground plane. The triple – mode resonator consists of two dual-mode resonators which are placed on different sides of dielectric layers. Electrical connection between the two resonators is realized by using a via-hole. We use the dual-mode resonator with the short circuited central stub. The filter is designed for the center frequency of 1 GHz. In order to reduce the simulation time for the filter design, we propose a new circuit model, because the circuit-level simulations are significantly faster than three-dimensional electromagnetic (3D EM) simulations. The 3D filter structure is decomposed into domains and each of them is modeled by a microwave network. The results of the 3D EM simulation and circuit-level simulation are in good agreement.
Keywords: Bandpass filter, Dual-mode resonator, Miniaturization, Multilayer technology, Triple – mode resonator.
Spatio-Temporal Image Inpainting for Video Applications
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DOI: https://doi.org/10.2298/SJEE170116004V
Abstract: Video inpainting or completion is a vital video improvement technique used to repair or edit digital videos. This paper describes a framework for temporally consistent video completion. The proposed method allows to remove dynamic objects or restore missing or tainted regions presented in a video sequence by utilizing spatial and temporal information from neighboring scenes. Masking algorithm is used for detection of scratches or damaged portions in video frames. The algorithm iteratively performs the following operations: achieve frame; update the scene model; update positions of moving objects; replace parts of the frame occupied by the objects marked for remove by using a background model. In this paper, we extend an image inpainting algorithm based texture and structure reconstruction by incorporating an improved strategy for video. Our algorithm is able to deal with a variety of challenging situations which naturally arise in video inpainting, such as the correct reconstruction of dynamic textures, multiple moving objects and moving background. Experimental comparisons to state-of-the-art video completion methods demonstrate the effectiveness of the proposed approach. It is shown that the proposed spatio-temporal image inpainting method allows restoring a missing blocks and removing a text from the scenes on videos.
Keywords: Inpainting, Patching, Masking, Spatio-temporal, Restoring of missing pixels, Video, Dynamic textures.
Optimal Synthesis of the Worm-Lever Mechanism for Humanoid Robots Shrug
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DOI: https://doi.org/10.2298/SJEE161117005P
Abstract: Emotions represent a significant means of nonverbal communication and their expression represents an important aspect of social robots functionality. There are two basic ways of expressing emotions. The first one is based on facial expressions that can be realized by moving a particular part of face or by displaying a picture on the screen that represents a face with characteristic features such as eyebrows, eyes, nose and mouth. Combining them is also possible. The second way of nonverbal communication is based on gestures, especially using arms. This paper presents an optimal synthesis of shrug mechanism for humanoid robots. Based on the set requirements the worm-lever mechanism is proposed. It has 1 DOF and enables simultaneous shrug of both shoulders. It consists of a worm which is meshed with two worm gears having different directions of rotation and two four-bar lever mechanisms whose input links are rigidly connected to the worm gears. Based on the kinematic-dynamic analysis the dynamic model is formed, the objective function is defined, the constraints are prescribed and the optimal synthesis is performed. The maximum torque on the input link of the lever mechanism, the driving torque of the complete worm-lever mechanism, the range of transmission angle and the rotation range of the worm gears are determined. The lever mechanism has high efficiency in all positions because the transmission angle has a high value during the whole movement. The worm mechanism enables a significant reduction of driving torque and has acceptable efficiency. The rotation range of the worm gear is small – the mechanism movement is very quick and therefore the shrug speed is large, which was the basic requirement for realization.
Keywords: Social humanoid robot, Shrug mechanism, Worm-lever mechanism, Optimal synthesis, Nonverbal communication, Body language.
Measurement Crankshaft Angular Speed Of An OM403 Engine
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DOI: https://doi.org/10.2298/SJEE1702257B
Abstract: In this paper, the methodology of the measurement of the angular speed of the crankshaft of a ten-cylinder diesel OM403 engine is presented, with regular and irregular engine operation. The angular velocity was measured under laboratory conditions, on already installed measuring equipment from the laboratory and on the break of a well known brand-Schenck, by using an opto-electronic incremental rotary encoder, a data acquisition module and the Lab View software for synchronization and management of the measuring equipment. The goal of this paper is to give a practical contribution to researches of measuring of crankshaft angular speed of the crankshaft engine OM 403.
Keywords: Measurement, Angular velocity, Engine.
Degradation and Performance Evaluation of PV Module in Desert Climate Conditions with Estimate Uncertainty in Measuring
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DOI: https://doi.org/10.2298/SJEE1702277F
Abstract: The performance of photovoltaic (PV) module is affected by outdoor conditions. Outdoor testing consists installing a module, and collecting electrical performance data and climatic data over a certain period of time. It can also include the study of long-term performance under real work conditions. Tests are operated in URAER located in desert region of Ghardaïa (Algeria) characterized by high irradiation and temperature levels. The degradation of PV module with temperature and time exposure to sunlight contributes significantly to the final output from the module, as the output reduces each year. This paper presents a comparative study of different methods to evaluate the degradation of PV module after a long term exposure of more than 12 years in desert region and calculates uncertainties in measuring. Firstly, this evaluation uses three methods: Visual inspection, data given by Solmetric PVA-600 Analyzer translated at STC and based on the investigation results of the translation equations as ICE 60891. Secondly, the degradation rates calculated for all methods. Finally, a comparison between a degradation rates given by Solmetric PVA -600 analyzer, calculated by simulation model and calculated by two methods (ICE 60891 procedures 1, 2). We achieved a detailed uncertainty study in order to improve the procedure and measurement instrument.
Keywords: Photovoltaic Module, Translation, Solmetric PVA-600 Analyzer, Visual inspection, Degradation Rate, Uncertainty Analysis.