Facta Universitatis-Series Electronics and Energetics最新文献

{"title":"Feature extraction for person gait recognition applications","authors":"Adnan Ramakic, Z. Bundalo, Zeljko Vidovic","doi":"10.2298/fuee2104557r","DOIUrl":"https://doi.org/10.2298/fuee2104557r","url":null,"abstract":"In this paper we present some features that may be used in person gait recognition applications. Gait recognition is an interesting way of people identification. During a gait cycle, each person creates unique patterns that can be used for people identification. Also, gait recognition methods ordinarily do not need interaction with a person and that is the main advantage of these methods. Features used in a person gait recognition methods can be obtained with widely available RGB and RGB-D cameras. In this paper we present a two features which are suitable for use in gait recognition applications. Mentioned features are height of a person and step length of a person. They may be extracted and were extracted from depth images obtained from RGB-D camera. For experimental purposes, we used a custom dataset created in outdoor environment using a long-range stereo camera.","PeriodicalId":44296,"journal":{"name":"Facta Universitatis-Series Electronics and Energetics","volume":"309 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78363477","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":"Autoscalabile ditributed anti-spam SMTP system based on kubernetes","authors":"Nadja Gavrilovic, V. Ciric","doi":"10.2298/fuee2104525g","DOIUrl":"https://doi.org/10.2298/fuee2104525g","url":null,"abstract":"Due to the increasing amount of spam email traffic, email users are in increasing danger, while email server resources are becoming overloaded. Therefore, it is necessary to protect email users, but also to prevent SMTP system overload during spam attacks. The aim of this paper is to design and implement an autoscalable distributed anti-spam SMTP system based on a Proof of work concept. The proposed solution extends SMTP protocol in order to enable the evaluation of the client?s credibility using the Proof of work algorithm. In order to prevent resource overload during spam attacks, the anti-spam SMTP system is implemented in a distributed environment, as a group of multiple anti-spam SMTP server instances. Kubernetes architecture is used for system distribution, configured with the possibility of autoscaling the number of antispam SMTP server instances depending on the system load. The implemented system is evaluated during a distributed spam attempt, simulated by a custom-made traffic generator tool. Various performance tests are given: (1) The proposed system?s impact on client?s behaviour and the overall amount of spam messages, (2) The performance of the undistributed anti-spam SMTP server during spam attack, in terms of resource load analysis (3) Autoscaling demonstration and evaluation of proposed distributed system?s performance during a spam attack. It is shown that the proposed solution has the possibility of reducing the amount of spam traffic, while processing tens of thousands of simultaneous SMTP client requests in a distributed environment.","PeriodicalId":44296,"journal":{"name":"Facta Universitatis-Series Electronics and Energetics","volume":"222 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75883932","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":"High-accuracy quasistatic numerical model for bodies of revolution tailored for RF measurements of dielectric parameters","authors":"A. Djordjević, D. Olćan, J. Petrovic, N. Obradović, S. Filipović","doi":"10.2298/fuee2101141d","DOIUrl":"https://doi.org/10.2298/fuee2101141d","url":null,"abstract":"We have developed rotationally symmetrical coaxial chambers for measurements of dielectric parameters of disk-shaped samples, in the frequency range from 1 MHz to several hundred MHz. The reflection coefficient of the chamber is measured and the dielectric parameters are hence extracted utilizing a high-accuracy quasistatic numerical model of the chamber and the sample. We present this model, which is based on the method of-moments solution of a set of integral equations for composite metallic and dielectric bodies. The equations are tailored to bodies of revolution. The model is efficient and accurate so that the major contribution of the measurement uncertainty comes from the measurement hardware.","PeriodicalId":44296,"journal":{"name":"Facta Universitatis-Series Electronics and Energetics","volume":"24 3 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78421874","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":"Acceptance of cloud computing in an airline company based on Roger’s diffusion of innovation theory","authors":"H. Kardanmoghaddam, A. Rajaei, S. Fatemi","doi":"10.2298/fuee2103461k","DOIUrl":"https://doi.org/10.2298/fuee2103461k","url":null,"abstract":"using cloud computing develops, one of the problems that managers face at the organization level is that the personnel cannot work with these systems, users do not accept these new systems and the problem of accepting these technologies, effective factors in accepting them and the existing barriers in accepting them by users are very important. In many organizations wherein cloud computing has been launched, a time period is required to accept this new system by their personnel. If this time period is less and the personnel can work with these systems earlier, the productivity increases in the organization. The present paper aims the analysis of effective factors on acceptance of cloud computing by personnel working in Birjand International Airport in South Khorasan County (Iran) based on Roger?s diffusion of innovation theory. Examination of effective factors on acceptance of cloud computing in an organization can pave the way for improving its implementation and performance. This research has been done by descriptive survey method and its community includes personnel working in different official and informatics departments of Birjand International Airport. The data gathering instrument was questionnaire and for determining questionnaire validity opinions of masters and for determining consistency Cronbach's alpha has been used. For data analysis descriptive and inferential statistics have been used. The results of present paper indicated that there is meaningful and positive relationship between acceptance features of cloud computing and perception elements of testability, comparative advantage, visibility, complexity, and compatibility of cloud computing with its acceptance rate and there is meaningful and negative relationship between features of perception of not needing cloud computing and its acceptance rate. But there was no meaningful relationship between perception of cloud computing test opportunity and its acceptance rate. As one of the modern ways of providing electronic service has been cloud computing in recent years and it has many benefits for air transportation systems, this paper presents a model for analysis of effective factors in acceptance of cloud computing among personnel of an airline company (airport) and it can be used for examining cloud acceptance in other air companies.","PeriodicalId":44296,"journal":{"name":"Facta Universitatis-Series Electronics and Energetics","volume":"32 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78658715","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":"Characterization of PTC effect in BaTiO3-ceramics as a special phase transition - fractal approach","authors":"Z. Vosika, V. Mitić, V. Paunovic, J. Manojlovic, G. Lazovic","doi":"10.2298/fuee2104499v","DOIUrl":"https://doi.org/10.2298/fuee2104499v","url":null,"abstract":"The applications of BaTiO3-ceramics are very important and constantly increasing nowadays. In that sense, we analyzed some phenomena related to intergranular effects. We used experimental data based on Murata powders and processing technology. Our original contribution to Heywang-Jonker-Daniels inter-granular capacity model is based on thermodynamic fractal analysis applied on phase transition in ceramic structures. In this case, PTCR effect has a diffuse first-order phase transition character in a modified Landau theory-fractal approach. Its basic properties are considered. This is an original contribution as a bridge between theoretical aspects of BaTiO3-ceramics and experimental results.","PeriodicalId":44296,"journal":{"name":"Facta Universitatis-Series Electronics and Energetics","volume":"20 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74109042","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":"A high efficiency pneumatic drive system using vane-type semi-rotary actuators","authors":"A. Rufer","doi":"10.2298/fuee2103415r","DOIUrl":"https://doi.org/10.2298/fuee2103415r","url":null,"abstract":"A compressed air driven generator is proposed, where the pneumatic energy is converted into mechanical energy using two vane-type rotational actuators. The use of a second actuator with a higher displacement in order to produce a thermodynamic expansion allows to reach a better energetic efficiency in comparison to the classical operation of such actuators. The alternating movement of the angular actuators is transformed into a unidirectional rotational motion with the help of a mechanical motion rectifier. The paper analyses the enhancement of the energetic performance of the system. An experimental set-up is also described. The performance of the new system is described, and the limits of its realization is commented on the base of experimental recordings of the evolution of the pressure in the chambers.","PeriodicalId":44296,"journal":{"name":"Facta Universitatis-Series Electronics and Energetics","volume":"1 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79500991","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":"Assessment of electrical interference on metallic pipeline from HV overhead power line in complex situation","authors":"R. Djekidel, S. Bessedik, A. Hadjadj","doi":"10.2298/fuee2101053d","DOIUrl":"https://doi.org/10.2298/fuee2101053d","url":null,"abstract":"Sharing corridors between high voltage alternating current (HVAC) power lines and metallic pipelines has become quite common. Voltages can be induced on pipelines from HV power lines, which may cause a risk of electric shock to the operator and serious corrosion damage on metallic pipelines. This paper aims to examine the capacitive coupling between aerial metallic pipelines and HV power lines in perfect parallelism case and in general situation which is formed by parallelism, approaches and crossings, using a combination of charge simulation method and Artificial Bee Colony (ABC) algorithm. The electric field at the pipeline's surface and the induced voltage on the pipeline are strongly affected by the pipeline separation distance. The presented simulation results are compared with those obtained from the admittance matrix analysis, a good agreement has been obtained.","PeriodicalId":44296,"journal":{"name":"Facta Universitatis-Series Electronics and Energetics","volume":"69 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80177201","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":"Evaluation of the magnetic field generated by a power cable in proximity of a joint bay: Comparison between two different approaches","authors":"G. Lucca","doi":"10.2298/fuee2104511l","DOIUrl":"https://doi.org/10.2298/fuee2104511l","url":null,"abstract":"The paper presents two different approaches for the evaluation of the magnetic flux density field produced by an underground power cable in proximity of areas where joint bays are present; as known, in those areas the field levels are generally much higher compared to the ones generated along the ordinary route. The first and more rigorous 3D approach takes into account the actual geometry of the power cable conductors in the joint bay, while the second one is based on a simplified 2D approach. The main result of the comparison is that the 2D approach, even at short lateral distances from the cable overestimates the field; therefore, one could adopt this method in order to rapidly and conservatively evaluate the distance of compliance (established by each specific national authority) from the cable in order to ensure protection of population from exposure to power frequency magnetic field.","PeriodicalId":44296,"journal":{"name":"Facta Universitatis-Series Electronics and Energetics","volume":"14 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74009574","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":"A new anomalous text detection approach using unsupervised methods","authors":"Elham Amouee, Morteza Zanjireh Mohammadi, Mahdi Bahaghighat, Mohsen Ghorbani","doi":"10.2298/fuee2004631a","DOIUrl":"https://doi.org/10.2298/fuee2004631a","url":null,"abstract":"Increasing size of text data in databases requires appropriate classification and analysis in order to acquire knowledge and improve the quality of decision-making in organizations. The process of discovering the hidden patterns in the data set, called data mining, requires access to quality data in order to receive a valid response from the system. Detecting and removing anomalous data is one of the pre-processing steps and cleaning data in this process. Methods for anomalous data detection are generally classified into three groups including supervised, semi-supervised, and unsupervised. This research tried to offer an unsupervised approach for spotting the anomalous data in text collections. In the proposed method, a combination of two approaches (i.e., clustering-based and distance-based) is used for detecting anomaly in the text data. In order to evaluate the efficiency of the proposed approach, this method is applied on four labeled data sets. The accuracy of Na¨ive Bayes classification algorithms and decision tree are compared before and after removal of anomalous data with the proposed method and some other methods such as Density-based spatial clustering of applications with noise (DBSCAN). Our proposed method shows that accuracy of more than 92.39% can be achieved. In general, the results revealed that in most cases the proposed method has a good performance.","PeriodicalId":44296,"journal":{"name":"Facta Universitatis-Series Electronics and Energetics","volume":"54 1","pages":"631-653"},"PeriodicalIF":0.6,"publicationDate":"2020-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91046053","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":"Application of cluster analysis in the behaviour of traffic participants relating to the use of safety systems and mobile phones","authors":"M. Blagojevic, Stefan Šošić","doi":"10.2298/fuee2004655b","DOIUrl":"https://doi.org/10.2298/fuee2004655b","url":null,"abstract":"This paper presents a cluster analysis related to the behavior of traffic\u0000 participants in relation to the use of safety systems and mobile phones. The\u0000 data on traffic behavior were downloaded from an open data portal in Serbia.\u0000 Three types of cluster analysis have been applied: hierarchical clustering,\u0000 Bayesian Information Criterion (BIC) clustering and model clustering. The\u0000 obtained results point to the various possibilities of using these three\u0000 clustering methods in the field of traffic and suggest further research.","PeriodicalId":44296,"journal":{"name":"Facta Universitatis-Series Electronics and Energetics","volume":"5 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2020-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78629199","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}