Електротехнички факултет [Научни радови] / Faculty of Electrical Engineering [Scientific papers]
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- СтавкаLeaf counting in the presence of occlusion in Arabidopsis thaliana plant using convolutional neural networks(SPIE, 2023) Štaka, Zorana; Mišic, MarkoPlants are crucial in providing sufficient food for the increasing global population. To be able to provide an appropriate amount of food, the maximization of agricultural output is needed while input needs to be minimized. For these purposes, plant phenotyping techniques, i.e., measuring and analyzing the physical and biochemical characteristics of plants, can be employed. One of the most essential indicators of the general health and development of the plant is the color, shape, and number of leaves. To analyze plant images and capture essential plant traits, various algorithms have been developed. However, one of the important challenges in developing these algorithms is the occlusion or overlapping of leaves and biomass. We present a solution for leaf counting in the presence of occlusion in the plant Arabidopsis thaliana that includes four different convolutional neural network architectures. Datasets from the Computer Vision Problems in Plant Phenotyping (CVPPP) 2017 challenge and Photon System Instruments were used. The results are discussed in detail and compared with the existing solutions. Results showed that our solutions for leaf counting are superior to the previous winners of the CVPPP challenges.
- СтавкаPower definitions for three-phase systems in terms of instantaneous symmetrical components(Elsevier, 2023) Mikulović, Jovan; Šekara, Tomislav; Forcan, MiodragThis paper considers power definitions for three-phase power systems with non-sinusoidal and unbalanced voltages and currents. By applying the Lyon transformation to three-phase voltages and currents, instantaneous symmetrical components are obtained and used to define powers. Definitions of instantaneous apparent and reactive powers are derived, as well as definitions of wellknown quantities based on rms values, such as apparent and reactive powers. The introduced set of power definitions based on the same mathematical framework could be used for time-instantaneous and time-average compensation. To provide correct calculation of powers for unbalanced three-phase four-wire systems, all wires and related quantities of the three-phase four-wire system are treated equally. The instantaneous apparent and reactive powers are also expressed in terms of instantaneous symmetrical components derived from the Clarke transformation. The proposed definitions are compared with other power definitions. In the case of a three-phase three-wire system, the proposed definitions give the same values of powers as the most known power definitions. In the case of a three-phase four-wire system, the proposed definitions give the same value of the apparent power as the DIN 40110 Standard and the same value of reactive power as the Currents' Physical Component theory. © 2017 Elsevier Inc. All rights reserved.
- СтавкаRenewable Energy-Powered Traffic Signalization as a Step to Carbon-Neutral Cities (The Case ofWestern Balkans)(MDPI, 2023) Vukovic, Marko; Miskic, Miroslav; Kastelan, Ivan; Lale, Srdjan; Forcan, Miodrag; Vukovic, Goran; Ikic, MarkoGlobal warming and its negative effect on the environment pose a great threat to the future of mankind. In order to overcome these challenges, EU countries have set the target of becoming climate neutral by 2050, a path defined through the policies of the European Green Deal. The Republic of Serbia and Bosnia and Herzegovina also agreed upon the same goal through the endorsement of the Green Agenda for the Western Balkans. One of the means to achieve this goal is by increasing the share of renewable energy sources. In this paper, we analyze the feasibility, challenges, and potential issues of substituting conventional traffic light signalization with signalization based on renewable energy sources on a national scale. An ad hoc questionnaire was used to collect data from representatives of most of the municipalities in the Republic of Srpska entity in Bosnia and Herzegovina and representatives of the city of Novi Sad in Serbia. In the city of Novi Sad, personal interviews were also carried out to collect additional information. The results of this research show that the implementation of solar-powered traffic lights is economically and environmentally viable. These results will provide the basis for understanding the benefits and challenges in the case of the application of traffic light signalization based on renewable energy sources.
- СтавкаA robust control design for multi-input LTI systems using discrete-time arbitrary order sliding mode approach(Elsevier, 2024) Peruničić-Draženović, Branislava; Milosavljević, Čedomir; Huseinbegović, Senad; Veselić, Boban; Petronijević, MilutinThis paper proposes a robust digital sliding mode control design for multi-input linear systems that provides the closed-loop system dynamics of an arbitrary order having a specified feasible spectrum of poles. By appropriate selection of auxiliary outputs according to the controllability indices of the system, the system is decoupled into a set of subsystems. The number of these subsystems is equal to the number of control inputs. The desired dynamic of the considered system is achieved using discrete-time higher order sliding mode, where the discrete-time sliding mode of appropriate order is realized in each subsystem. The robustness is based on the fact that the previous values of the matched disturbances are directly reflected in the present value of the switching variables and it will be enhanced by using an estimator/compensator based on integral of sliding function. This control structure looks like discrete-time super-twisting control. Effectiveness of the proposed control is analyzed and its impact on the control system performances is derived. The proposed control approach is illustrated by simulation examples.
- СтавкаA Zonal Approach for Wide-Area Temporary Voltage Quality Assessment in a Smart Grid(MDPI, 2024) Forcan, Miodrag; Simović, Aleksandar; Jokić, Srđan; Forcan, JovanaWide-area voltage quality assessment represents one of the mandatory objectives for distribution system operators in the development of advanced distribution management systems supporting smart grid requirements. This paper introduces a zonal approach for wide-area temporary voltage quality evaluation in a distribution network. The concept of temporary voltage quality evaluation and assessment is recommended to incentivize active/online management of voltage quality issues. A decision support system based on simple deterministic rules is proposed for rating the voltage quality zones in a distribution network and making recommendations to the distribution system operator. Voltage RMS level, unbalance, and total harmonic distortion are considered voltage quality indices representing the inputs in the decision support system. Residential, commercial, and industrial load types are considered when setting the thresholds for voltage quality indices. The proposed zonal approach for the division of distribution networks in voltage quality zones is applied to the example of a typical European-type distribution network. The operation of a decision support system is tested using the developed distribution smart grid model. The following simulation case studies are conducted: loads with low power factors, manual voltage regulation at MV/LV transformers, unbalanced loads, integration of solar power plant, and nonlinear loads. The obtained simulation results reveal the benefits of the proposed voltage quality assessment approach. Cybersecurity challenges that may impact the proposed approach are addressed, including security vulnerabilities, data privacy, and resilience to cyber threats.