Abstract Spam annoys users and poses a security threat. This article proposes a spam filter based on geographical location of the sender determined by IP geolocation. This filter was implemented as a plugin to the SpamAssassin anti-spam software. The plugin allows to define a penalty score for specific countries sending spam. The proposed filter was tested on a dataset of 1500 e-mails consisting of 1200 spam and 300 legitimate e-mails. The Matthews correlation coefficient of the filter has a value of 0.222. This indicates that the proposed spam filter contributes to the correct spam filtering.
{"title":"Spam filter based on geographical location of the sender","authors":"Tomáš Caha, Martin Kovařík","doi":"10.2478/jee-2022-0038","DOIUrl":"https://doi.org/10.2478/jee-2022-0038","url":null,"abstract":"Abstract Spam annoys users and poses a security threat. This article proposes a spam filter based on geographical location of the sender determined by IP geolocation. This filter was implemented as a plugin to the SpamAssassin anti-spam software. The plugin allows to define a penalty score for specific countries sending spam. The proposed filter was tested on a dataset of 1500 e-mails consisting of 1200 spam and 300 legitimate e-mails. The Matthews correlation coefficient of the filter has a value of 0.222. This indicates that the proposed spam filter contributes to the correct spam filtering.","PeriodicalId":15661,"journal":{"name":"Journal of Electrical Engineering-elektrotechnicky Casopis","volume":"73 1","pages":"292 - 298"},"PeriodicalIF":0.8,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46786274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This letter proposes a concept to discriminate an electrical fault from a cyber attack in the modern power system. A cyber attack factor is introduced which may mislead the bus voltage stability virtually at load buses. The proposed cyber attack models are validated by executing multiple cyber attacks at a time on Western system coordinating council (WSCC) 9 bus test power system by using Siemens PSS/E and MATLAB softwares. Further, the impact of electrical fault and cyber attack on the WSCC 9 bus test power systems voltage stability has been analysed to develop a discrimination algorithm in reference to chosen load index. Despite its simplicity, the proposed discrimination algorithm is robust, accurate and quite suitable to develop intelligent measures for mal-operations against cyber attacks in the smart electric grid.
{"title":"A concept for discrimination of electrical fault from cyber attack in smart electric grid","authors":"Aniruddha Agrawal, Shaik Affijulla","doi":"10.2478/jee-2022-0039","DOIUrl":"https://doi.org/10.2478/jee-2022-0039","url":null,"abstract":"Abstract This letter proposes a concept to discriminate an electrical fault from a cyber attack in the modern power system. A cyber attack factor is introduced which may mislead the bus voltage stability virtually at load buses. The proposed cyber attack models are validated by executing multiple cyber attacks at a time on Western system coordinating council (WSCC) 9 bus test power system by using Siemens PSS/E and MATLAB softwares. Further, the impact of electrical fault and cyber attack on the WSCC 9 bus test power systems voltage stability has been analysed to develop a discrimination algorithm in reference to chosen load index. Despite its simplicity, the proposed discrimination algorithm is robust, accurate and quite suitable to develop intelligent measures for mal-operations against cyber attacks in the smart electric grid.","PeriodicalId":15661,"journal":{"name":"Journal of Electrical Engineering-elektrotechnicky Casopis","volume":"73 1","pages":"299 - 304"},"PeriodicalIF":0.8,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45683614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Rouissat, Mohammed Belkheir, Hichem Sid Ahmed Belkhira
Abstract Routing protocol for low power and lossy networks (RPL) has been proposed for power, memory, and processing constrained devices. Owing to their constrained, RPL-based networks are exposed to a wide range of security attacks that mainly include control message tampering. In this paper we propose and study a modified version number attack, based on flooding the network by falsified incremented version numbers. The obtained results show that the modified attack led to an immense increase in the overhead, 1426%, compared with the attack-free case, and an increase of 182 % in the total energy consumption. When it comes to PDR a degradation to 4.7% has been recorded, affecting the reliability of the network. On the other hand, the latency also showed an increase from 0.24 s in the attack-free case to 0.89 s, which is mainly due to the high congestion created by the attack.
{"title":"A potential flooding version number attack against RPL based IOT networks","authors":"M. Rouissat, Mohammed Belkheir, Hichem Sid Ahmed Belkhira","doi":"10.2478/jee-2022-0035","DOIUrl":"https://doi.org/10.2478/jee-2022-0035","url":null,"abstract":"Abstract Routing protocol for low power and lossy networks (RPL) has been proposed for power, memory, and processing constrained devices. Owing to their constrained, RPL-based networks are exposed to a wide range of security attacks that mainly include control message tampering. In this paper we propose and study a modified version number attack, based on flooding the network by falsified incremented version numbers. The obtained results show that the modified attack led to an immense increase in the overhead, 1426%, compared with the attack-free case, and an increase of 182 % in the total energy consumption. When it comes to PDR a degradation to 4.7% has been recorded, affecting the reliability of the network. On the other hand, the latency also showed an increase from 0.24 s in the attack-free case to 0.89 s, which is mainly due to the high congestion created by the attack.","PeriodicalId":15661,"journal":{"name":"Journal of Electrical Engineering-elektrotechnicky Casopis","volume":"73 1","pages":"267 - 275"},"PeriodicalIF":0.8,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41426005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper concentrates on an algorithm with model predictive control for current and distributed MPPT for cascaded H-bridge multilevel photovoltaic (PV) inverter applications. In conventional method, in each sampling period, a discrete-time model is employed to predict the current future values for all vectors of voltage. The voltage vector will be approved if it minimizes the cost function. Because multilevel inverter has so many available voltage vectors, there is a large quantity of calculations, hence it makes difficult in implementing the normal control method. A varied control strategy that extensively decreases the calculations volume and eliminating common-mode voltage is proposed. To raise the PV modules performance and enlarge the systems power, a distributed maximum power point tracking (MPPT) control scheme for each phase of multilevel inverter is offered, that allows its DC-link voltage to be regulated separately. The recommended approach is double-checked by using a model simulated in MATLAB-Simulink software.
{"title":"Model predictive control for distributed MPPT algorithm of cascaded H-bridge multilevel grid-connected PV inverters","authors":"Bao Binh Pho, Chung Mai-Van, M. Trong, P. Vu","doi":"10.2478/jee-2022-0040","DOIUrl":"https://doi.org/10.2478/jee-2022-0040","url":null,"abstract":"Abstract This paper concentrates on an algorithm with model predictive control for current and distributed MPPT for cascaded H-bridge multilevel photovoltaic (PV) inverter applications. In conventional method, in each sampling period, a discrete-time model is employed to predict the current future values for all vectors of voltage. The voltage vector will be approved if it minimizes the cost function. Because multilevel inverter has so many available voltage vectors, there is a large quantity of calculations, hence it makes difficult in implementing the normal control method. A varied control strategy that extensively decreases the calculations volume and eliminating common-mode voltage is proposed. To raise the PV modules performance and enlarge the systems power, a distributed maximum power point tracking (MPPT) control scheme for each phase of multilevel inverter is offered, that allows its DC-link voltage to be regulated separately. The recommended approach is double-checked by using a model simulated in MATLAB-Simulink software.","PeriodicalId":15661,"journal":{"name":"Journal of Electrical Engineering-elektrotechnicky Casopis","volume":"73 1","pages":"305 - 309"},"PeriodicalIF":0.8,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49130344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper presents a compact implantable antenna’s design, fabrication, and measurement for biotelemetry applications. The proposed design with the size of 255 mm3 provides a triple-band operation that covers all the Medical Implant Communication Service (MICS: 402 MHz), Medical Device Radiocommunications Service (MedRadio: 405 MHz), and Industrial, Scientific, and Medical (ISM: 433, 915 and 2450 MHz) bands simultaneously. The compact structure with triple- band performance is essentially achieved by using a spiral-like radiator loaded with meandered and internal gear-shaped elements excited by a vertical coaxial probe feed. Also, the slots-loaded partial ground plane is utilized to improve impedance matching at the desired frequency bands. The design and analysis of the antenna were carried out using the Ansoft HFSS software in a homogenous skin model and the CST Microwave Studio in a realistic human model. The proposed antenna was fabricated to validate the simulated results, and characteristics of its return loss and radiation patterns were measured in minced pork meat. Moreover, realized gains and specific absorption rate (SAR) values of the antenna were numerically computed using the simulators. Based on the simulated and measured results, the proposed antenna performance was found to be comparable to the limited number of multiband implantable antenna designs reported in the recent literature.
{"title":"Compact triple-band implantable antenna for multitasking medical devices","authors":"Ö. Çeli̇k, S. C. Basaran","doi":"10.2478/jee-2022-0022","DOIUrl":"https://doi.org/10.2478/jee-2022-0022","url":null,"abstract":"Abstract This paper presents a compact implantable antenna’s design, fabrication, and measurement for biotelemetry applications. The proposed design with the size of 255 mm3 provides a triple-band operation that covers all the Medical Implant Communication Service (MICS: 402 MHz), Medical Device Radiocommunications Service (MedRadio: 405 MHz), and Industrial, Scientific, and Medical (ISM: 433, 915 and 2450 MHz) bands simultaneously. The compact structure with triple- band performance is essentially achieved by using a spiral-like radiator loaded with meandered and internal gear-shaped elements excited by a vertical coaxial probe feed. Also, the slots-loaded partial ground plane is utilized to improve impedance matching at the desired frequency bands. The design and analysis of the antenna were carried out using the Ansoft HFSS software in a homogenous skin model and the CST Microwave Studio in a realistic human model. The proposed antenna was fabricated to validate the simulated results, and characteristics of its return loss and radiation patterns were measured in minced pork meat. Moreover, realized gains and specific absorption rate (SAR) values of the antenna were numerically computed using the simulators. Based on the simulated and measured results, the proposed antenna performance was found to be comparable to the limited number of multiband implantable antenna designs reported in the recent literature.","PeriodicalId":15661,"journal":{"name":"Journal of Electrical Engineering-elektrotechnicky Casopis","volume":"73 1","pages":"166 - 173"},"PeriodicalIF":0.8,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47835778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Polymeric insulation for HVDC cable is attracting more attention in the modern power transmission system. Especially, the thermoplastic material is desirable for power cable insulation because of its recyclability and ease of processing. Thermoplastic material development is a good alternative to cross-linked polyethylene in the future. Polypropylene has the advantage of avoiding by-products during cable production, which can minimize space accumulation and degassing costs. Therefore, this study investigates the influence of nanofillers on the structural properties of isotactic polypropylene. In addition, the proposed composite material’s morphology, melting, dielectric permittivity, and breakdown strength are examined. Different weight percentages of inorganic nanofillers such as TiO2 and ZnO are used to make nanocomposite thin films. With increasing filler concentration, the dielectric constant of the nanocomposite thin film increases. Apart from that, the dielectric loss of the TiO2 nanocomposite thin film increases with weight percentage initially and it falls nearer to virgin material at a higher frequency. The breakdown strength of the nanocomposite materials shows a similar variation with filler concentration. TiO2 is more resistant to deterioration than ZnO composite. Based on the results of the complete investigation, the TiO2 nanocomposite is better suited for the insulation of HVDC cables.
{"title":"Influence of nanofiller concentration on polypropylene nanocomposites for high voltage cables","authors":"Sendil Kumar Angalane, Elanseralathan Kasinathan","doi":"10.2478/jee-2022-0023","DOIUrl":"https://doi.org/10.2478/jee-2022-0023","url":null,"abstract":"Abstract Polymeric insulation for HVDC cable is attracting more attention in the modern power transmission system. Especially, the thermoplastic material is desirable for power cable insulation because of its recyclability and ease of processing. Thermoplastic material development is a good alternative to cross-linked polyethylene in the future. Polypropylene has the advantage of avoiding by-products during cable production, which can minimize space accumulation and degassing costs. Therefore, this study investigates the influence of nanofillers on the structural properties of isotactic polypropylene. In addition, the proposed composite material’s morphology, melting, dielectric permittivity, and breakdown strength are examined. Different weight percentages of inorganic nanofillers such as TiO2 and ZnO are used to make nanocomposite thin films. With increasing filler concentration, the dielectric constant of the nanocomposite thin film increases. Apart from that, the dielectric loss of the TiO2 nanocomposite thin film increases with weight percentage initially and it falls nearer to virgin material at a higher frequency. The breakdown strength of the nanocomposite materials shows a similar variation with filler concentration. TiO2 is more resistant to deterioration than ZnO composite. Based on the results of the complete investigation, the TiO2 nanocomposite is better suited for the insulation of HVDC cables.","PeriodicalId":15661,"journal":{"name":"Journal of Electrical Engineering-elektrotechnicky Casopis","volume":"73 1","pages":"174 - 181"},"PeriodicalIF":0.8,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44577166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Electromagnetic shielding enclosure is used to protect electronic circuits against external EMI. Aperture on the enclosure, which is necessary for various reasons such as mounting connector, ventilation attenuates shielding effectiveness (SE) of the enclosure. Enlarging enclosure dimensions makes SE get better. Yet, they canot be designed so large due to weight and dimension considerations for EV. When the dimensions of the shielding enclosure remain fixed and the aperture is to have a particular area, it is essential to optimize aperture dimensions to increase SE. In this paper, an optimization methodology based on PSO is designed to obtain the optimal SE for a particular dimension range. The study also provides a comparative analysis between designed optimization methodology and the one based on genetic algorithm in the literature. Obtained SE results indicate that the optimization methodology establishes a very good agreement with the results in the literature. Moreover, it has faster convergence and higher calculation accuracy than GA and it utilizes a smaller number of parameters thanks to its simplicity. Finally, it is concluded that through designed optimization methodology in this study, SE of the enclosure can be raised by optimizing aperture dimensions when the dimensions of shielding enclosure remain fixed.
{"title":"Analysing the shielding effectiveness of rectangular enclosure by determining aperture dimensions with particle swarm optimization","authors":"Sunay Güler","doi":"10.2478/jee-2022-0024","DOIUrl":"https://doi.org/10.2478/jee-2022-0024","url":null,"abstract":"Abstract Electromagnetic shielding enclosure is used to protect electronic circuits against external EMI. Aperture on the enclosure, which is necessary for various reasons such as mounting connector, ventilation attenuates shielding effectiveness (SE) of the enclosure. Enlarging enclosure dimensions makes SE get better. Yet, they canot be designed so large due to weight and dimension considerations for EV. When the dimensions of the shielding enclosure remain fixed and the aperture is to have a particular area, it is essential to optimize aperture dimensions to increase SE. In this paper, an optimization methodology based on PSO is designed to obtain the optimal SE for a particular dimension range. The study also provides a comparative analysis between designed optimization methodology and the one based on genetic algorithm in the literature. Obtained SE results indicate that the optimization methodology establishes a very good agreement with the results in the literature. Moreover, it has faster convergence and higher calculation accuracy than GA and it utilizes a smaller number of parameters thanks to its simplicity. Finally, it is concluded that through designed optimization methodology in this study, SE of the enclosure can be raised by optimizing aperture dimensions when the dimensions of shielding enclosure remain fixed.","PeriodicalId":15661,"journal":{"name":"Journal of Electrical Engineering-elektrotechnicky Casopis","volume":"73 1","pages":"182 - 189"},"PeriodicalIF":0.8,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45499946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper is devoted to design of a robust controller for an uncertain continuous-time linear polytopic system. The design procedure will take place in two steps. In the first step, we calculate the robust stability boundary of a closed loop system. Then on the basis of the result obtained in this way, we select a robust controller design method that accepts the calculated stability boundary. This procedure allows better implementation of the second step of the designed robust controller. Two examples of application of the proposed method follow finally, which illustrate its effectiveness.
{"title":"Robust boundary of stability and design of robust controller in uncertain polytopic linear systems","authors":"J. Paulusová, L. Körösi, V. Veselý","doi":"10.2478/jee-2022-0028","DOIUrl":"https://doi.org/10.2478/jee-2022-0028","url":null,"abstract":"Abstract This paper is devoted to design of a robust controller for an uncertain continuous-time linear polytopic system. The design procedure will take place in two steps. In the first step, we calculate the robust stability boundary of a closed loop system. Then on the basis of the result obtained in this way, we select a robust controller design method that accepts the calculated stability boundary. This procedure allows better implementation of the second step of the designed robust controller. Two examples of application of the proposed method follow finally, which illustrate its effectiveness.","PeriodicalId":15661,"journal":{"name":"Journal of Electrical Engineering-elektrotechnicky Casopis","volume":"73 1","pages":"209 - 214"},"PeriodicalIF":0.8,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47122572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper presents the application of a phase shifter with a ferrite Y-circulator in band S. Global literature addresses primarily the basic types of power waveguide phase shifters, however, there has been minimal literature on a phase shifter that uses a ferrite circulator for phase shifting. The paper describes theoretical and practical results where a ferrite circulator is used to shift the phase. A power phase shifter utilizing a ferrite circulator could be used in power applications where high demands are placed on the phase shift accuracy with minimal power losses. The phase shift is handled by a tunable waveguide short circuit that is connected to the port 2 of the ferrite circulator. By changing the waveguide length, the phase is changed. The measured results are compared with theoretical calculations and evaluated. The proposed phase shifter utilizing the ferrite circulator has its advantages in its simple design, in the accuracy of the phase adjustment and in the speed of the tuning. Another great advantage is its quite low cost due to its simple design.
{"title":"Waveguide power phase shifter with a ferrite circulator in S-band","authors":"M. Popela, J. Lacik, L. Dražan","doi":"10.2478/jee-2022-0029","DOIUrl":"https://doi.org/10.2478/jee-2022-0029","url":null,"abstract":"Abstract This paper presents the application of a phase shifter with a ferrite Y-circulator in band S. Global literature addresses primarily the basic types of power waveguide phase shifters, however, there has been minimal literature on a phase shifter that uses a ferrite circulator for phase shifting. The paper describes theoretical and practical results where a ferrite circulator is used to shift the phase. A power phase shifter utilizing a ferrite circulator could be used in power applications where high demands are placed on the phase shift accuracy with minimal power losses. The phase shift is handled by a tunable waveguide short circuit that is connected to the port 2 of the ferrite circulator. By changing the waveguide length, the phase is changed. The measured results are compared with theoretical calculations and evaluated. The proposed phase shifter utilizing the ferrite circulator has its advantages in its simple design, in the accuracy of the phase adjustment and in the speed of the tuning. Another great advantage is its quite low cost due to its simple design.","PeriodicalId":15661,"journal":{"name":"Journal of Electrical Engineering-elektrotechnicky Casopis","volume":"73 1","pages":"215 - 220"},"PeriodicalIF":0.8,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45800542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Shape representation and retrieval are essential research topics of computer vision. This paper proposes a novel feature set to be used in content-based image retrieval systems. The proposed method is an extended version of our previous study which uses contour information of shapes. The previous study calculated the center of mass (CoM) of the shape. By taking the CoM as origin, we created imaginary vectors in every angular direction. From each vector, we extracted three features which are the number of intersections between vector and contour, average distance of intersection points to CoM, and standard deviation of these points. In this method, we extract novel features and decrease the size of the feature set to decrease the computation time. We divide the shape into quadrants and represent each quadrant by nine features. Each shape image is represented by a 4x9 feature vector. We tested the proposed method on MPEG-7 and ETH-80 datasets and compared it with the state-of-art. According to the results, our method decreased the computation time dramatically while giving a state-of-art level retrieval accuracy.
{"title":"Quadrant-based contour features for accelerated shape retrieval system","authors":"M. E. Yıldırım","doi":"10.2478/jee-2022-0026","DOIUrl":"https://doi.org/10.2478/jee-2022-0026","url":null,"abstract":"Abstract Shape representation and retrieval are essential research topics of computer vision. This paper proposes a novel feature set to be used in content-based image retrieval systems. The proposed method is an extended version of our previous study which uses contour information of shapes. The previous study calculated the center of mass (CoM) of the shape. By taking the CoM as origin, we created imaginary vectors in every angular direction. From each vector, we extracted three features which are the number of intersections between vector and contour, average distance of intersection points to CoM, and standard deviation of these points. In this method, we extract novel features and decrease the size of the feature set to decrease the computation time. We divide the shape into quadrants and represent each quadrant by nine features. Each shape image is represented by a 4x9 feature vector. We tested the proposed method on MPEG-7 and ETH-80 datasets and compared it with the state-of-art. According to the results, our method decreased the computation time dramatically while giving a state-of-art level retrieval accuracy.","PeriodicalId":15661,"journal":{"name":"Journal of Electrical Engineering-elektrotechnicky Casopis","volume":"73 1","pages":"197 - 202"},"PeriodicalIF":0.8,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48918590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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