{"title":"Optimal siting of capacitors in distribution grids considering electric vehicle load growth using improved flower pollination algorithm","authors":"Varaprasad Janamala","doi":"10.2298/sjee2203329j","DOIUrl":"https://doi.org/10.2298/sjee2203329j","url":null,"abstract":"The optimal VAr compensation using capacitor banks (CBs) in radial distribution networks (RDNs) is solved in this paper while taking the growth of the load from electric vehicles (EVs) into consideration. This is accomplished by adapting an improved variant of the flower pollination algorithm (IFPA) with an enhanced local search capability. The primary objective of determining the locations and sizes of CBs is to minimize the distribution losses in the operation and control of RDNs. Additionally, the effect of CBs is shown by the increased net savings, greater voltage stability, and improved voltage profile. A voltage stability index (VSI) was used in the optimization process to determine the predefined search space for CB locations, and a double-direction learning strategy (DLS) was then considered to optimize the locations and sizes while maintaining a balance between the exploration and exploitation phases. Three IEEE RDNs were used to simulate various EV load increase scenarios as well as typical loading situations. According to a comparison with the literature, the IPFA produced global optimum results, and the proposed CBs allocation approach demonstrated enhanced performance in RDNs under all scenarios of EV load growth.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68755461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Tumor detection using brain MRI and low-dimension co-occurrence feature approach","authors":"Marta Mirkov, A. Gavrovska","doi":"10.2298/sjee2203273m","DOIUrl":"https://doi.org/10.2298/sjee2203273m","url":null,"abstract":"Research in medical imaging focuses on methods useful in computer-aided diagnosis systems. In modern times, these systems often have automatic detection of regions of interest, and imaging technologies offer numerous advantages, like the possibility of developing reliable assisting algorithms. Magnetic Resonance Imaging (MRI) provides compelling features for brain tumor detection due to good soft tissue contrast and has important clinical value. To help clinicians in making diagnoses, current algorithms for processing and medical image classification may depend on intricate deep learning designs that demand large hardware resources and lengthy execution times. This is with no doubt helpful in understanding disease mechanisms and in labeling difficult instances for brain tumor identification. On the other hand, statistical low-dimension feature sets including co-occurrence-based ones could be useful in dealing with tumor detection avoiding possible complexity. In this paper, statistical approaches for feature extraction and reduction are analyzed for MRI brain tumor classification, and the evaluation of the results is presented on one of the publicly available brain tumor detection database commonly used for machine learning tasks. Bayes and kNN classifiers are applied for the analysis, as well as four distance metrics, and two methods for feature reduction. The results seem promising in developing a simple and less hardware-demanding procedure.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68755375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Milica Spasojevic-Savkovic, Zoran Kićanović, P. Spasojevic, Milentije Luković
{"title":"New catalysts for formic acid fuel cells","authors":"Milica Spasojevic-Savkovic, Zoran Kićanović, P. Spasojevic, Milentije Luković","doi":"10.2298/sjee2203387s","DOIUrl":"https://doi.org/10.2298/sjee2203387s","url":null,"abstract":"Thallium adatoms deposited at under-potentials have shown the catalytic effect during the electrooxidation of formic acid on platinum ruthenium alloys. At Pt/Ru with an optimal coverage degree with adatoms Tl, HCOOH is oxidized at nearly 180 mV more negative potential than at Pt/Ru electrodes. The catalytic effect of modified Pt/Ru electrodes is plausibly caused by interaction of the Tl adatoms, located at Pt atoms with OH species of adjacent Ru atoms. These interactions stabilize Ru-OH species and allows for their formation at more negative potentials than at the Pt/Ru electrodes. The Ru-OH species oxidize firmly bound intermediates COad and thus release the Pt atoms for the oxidation of subsequent HCOOH molecules. The catalytic effect is probably caused by the third-body effect.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68755724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Snort ids system visualization interface for alert analysis","authors":"Nadja Gavrilovic, V. Ciric, Nikola Lozo","doi":"10.2298/sjee2201067g","DOIUrl":"https://doi.org/10.2298/sjee2201067g","url":null,"abstract":"Over the past decades, the rapid Internet development and the growth in the number of its users have raised various security issues. Therefore, it is of great importance to ensure the security of the network in order to enable the safe exchange of confidential data, as well as their integrity. One of the most important components of network attack detection is an Intrusion Detection System (IDS). Snort IDS is a widely used intrusion detection system, which logs alerts after detecting potentially dangerous network packets. A major challenge in network monitoring is the high volume of generated IDS alerts. A necessary step in successful network protection is the analysis of the great amount of logged alerts in search of deviations from normal traffic that may indicate an intrusion. The goal of this paper is to design and implement a visualization interface for IDS alert analysis, which graphically presents alerts generated by Snort IDS. Also, the proposed system classifies the alerts according to the most important attack parameters, and allows the users to understand evolving network situations and easily detect possible traffic irregularities. An environment in which the system has been tested in real-time is described, and the results of attack detection and classification are given. One of the detected attacks is analyzed in detail, as well as the method of its detection and its possible consequences.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68754862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jelena Medarevic, Marija M. Novičić, Marko Marković
{"title":"Feasibility test of activity index summary metric in human hand activity recognition","authors":"Jelena Medarevic, Marija M. Novičić, Marko Marković","doi":"10.2298/sjee2202225m","DOIUrl":"https://doi.org/10.2298/sjee2202225m","url":null,"abstract":"Activity monitoring is a technique for assessing the physical activity that a person undertakes over some time. Activity Index (AI) is a metric that summarizes the raw measurements from tri-axial accelerometers, often used for measuring physical activity. Our research compared the Activity Index for different activity groups and hand usage [1]. We also tested this metric as a classification feature, and how different data acquisition and segmentation parameter configurations influence classification accuracy. Data acquisition was done with a previously developed system that includes a smartwatch on each wrist and a smartphone placed in the subject?s pocket; raw data from smartwatch accelerometers was used for the analysis. We calculated the Activity Index for labeled data segments and used ANOVA1 statistical test with Bonferroni correction. Significant differences were found between cases of hand usage (left, right, none, both). In the next analysis phase, the Activity Index was used as the classification feature with three supervised machine learning algorithms-Support Vector Machine, k-Nearest Neighbors, and Random Forest. The best accuracy (measured by F1 score) of classifying hand usage was achieved by using the Random Forest algorithm, 50 Hz sampling frequency, and a window of 10 s without overlap for AI calculation, and it was 97%. On the other hand, the classification of activity groups had a low accuracy, which indicated that a specific activity group can?t be identified by using only one simple feature.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68755606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Circularly polarized quasi-rectangular patch UWB antenna for GPR applications","authors":"A. Chaabane, M. Guerroui, Djelloul Aissaoui","doi":"10.2298/sjee2203261c","DOIUrl":"https://doi.org/10.2298/sjee2203261c","url":null,"abstract":"In this paper, a Circularly Polarized (CP) rectangular patch Ultra-Wideband (UWB) antenna is presented for Ground Penetrating Radar (GPR) applications. The designed geometry is constructed of a quasi-rectangular radiator and a partial ground plane. It is printed on the low-cost FR-4 substrate that has a compact size of 25?30?1.5 mm3. The calculated Impedance Bandwidth (IBW) of the proposed CP quasi-rectangular patch antenna is spanning from 3.16 GHz to 13.7 GHz (125.03%). Moreover, the measured IBW of the fabricated prototype is spanning from 3.2 GHz to greater than 14 GHz (>125.58%) which covers the entire UWB range. Besides, the designed antenna reveals a wide Axial Ratio Band-Width (ARBW) extending from 4.23 GHz to 7.02 GHz (49.6%). Therefore, stable radiation patterns with an agreeable peak gain and high radiation efficiency are simulated over the whole working bandwidth.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68755326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Modeling and practical implementation of the optimal wireless security gateway for the industrial automation network","authors":"I. Nevliudov, S. Novoselov, O. Sychova","doi":"10.2298/sjee2203303n","DOIUrl":"https://doi.org/10.2298/sjee2203303n","url":null,"abstract":"Reducing energy consumption in networks of IoT devices is very important. This paper presents the results of experimental studies of the proposed method of reducing power consumption for the protective gateway of the industrial network. Research was conducted for devices built on Lora modules. The LoRa Modem Calculator software from Semtech was used as a modeling tool. The recommended values of the program registers are given to achieve optimal energy consumption parameters for data reception and transmission modes. Information about the prototype is given and its practical implementation is shown. The developed prototype of the gateway implements the ?Protocol Transformation? method, which allows removing possible dangerous inserts from the data packets received by the gateway. This can improve the security of packets from the gateway to IoT devices and back, and thus the network as a whole.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68755427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aleksandar Jokic, Lazar Djokic, Milica Petrović, Z. Miljković
{"title":"Data augmentation methods for semantic segmentation-based mobile robot perception system","authors":"Aleksandar Jokic, Lazar Djokic, Milica Petrović, Z. Miljković","doi":"10.2298/sjee2203291j","DOIUrl":"https://doi.org/10.2298/sjee2203291j","url":null,"abstract":"Data augmentation has become a standard technique for increasing deep learning models? accuracy and robustness. Different pixel intensity modifications, image transformations, and noise additions represent the most utilized data augmentation methods. In this paper, a comprehensive evaluation of data augmentation techniques for mobile robot perception system is performed. The perception system based on a deep learning model for semantic segmentation is augmented by 17 techniques to obtain better generalization characteristics during the training process. The deep learning model is trained and tested on a custom dataset and utilized in real-time scenarios. The experimental results show the increment of 6.2 in mIoU (mean Intersection over Union) for the best combination of data augmentation strategies.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68755397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"C-V and I-V characterisation of CdS/CdTe thin film solar cell using defect density model","authors":"D. Pal, Soumee Das","doi":"10.2298/sjee2102255p","DOIUrl":"https://doi.org/10.2298/sjee2102255p","url":null,"abstract":"This paper presents a detailed study of the current-voltage (I-V) and\u0000 capacitance-voltage (C-V) measurements made on a CdS/CdTe based solar cell\u0000 by numerical modeling. Implementation of the simulated cell having a\u0000 superstrate configuration was done with the help of SCAPS program using\u0000 defect density model. The I-V characterisation includes window and absorber\u0000 layer optimisation based on various factors including the impurity doping\u0000 concentration, thickness and defect density. The energy band diagram,\u0000 spectral response and currentvoltage plot of the optimised cell\u0000 configuration are shown. C-V characterisation (Mott-Schottky analysis) of\u0000 the solar cell is conducted at different low frequencies to determine the\u0000 flatband potential, carrier concentration and to validate the reliability of\u0000 the results. The optimum device performance was obtained when the active\u0000 layer was 2 ?m thick with a doping level of 1?1015/cm3.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42349658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Video coding and constant quality evaluation using 4k aomenc-AV1 and rav1e-AV1 formats","authors":"M. Milivojević, D. Dujković, A. Gavrovska","doi":"10.2298/sjee2102139m","DOIUrl":"https://doi.org/10.2298/sjee2102139m","url":null,"abstract":"It is much expected from the relatively novel, open, royalty-free AV1\u0000 (Alliance for Open Media (AOMedia) Video 1) standard. At this moment, there\u0000 are many new variants of AV1 format. It is designed for efficient video\u0000 internet delivery and high-quality video transmission. AV1 is recognized as\u0000 Google?s VP9 format successor. One of the reference tools used so far for\u0000 testing AV1 is libaom- AV1. Nevertheless, due to its time-consuming\u0000 performance, there are now different available standalone solutions for\u0000 experimental analysis. Here, one such solution AOMedia?s standalone aomenc\u0000 (aomenc-AV1) is tested in order to analyze quality assessment based on\u0000 constant quality constraint factor. Three different metrics are calculated\u0000 for various 4k video content of the same frame rate. Moreover, rav1e\u0000 implementation was tested for the same visual data, where rav1e-AV1 also\u0000 represents an AV1 video encoder, which is considered reliable and suitable\u0000 in most cases, where libaom is not applicable. In this paper, the comparison\u0000 results between aomenc-AV1 and rav1e-AV1 are shown.","PeriodicalId":37704,"journal":{"name":"Serbian Journal of Electrical Engineering","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46510439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}