Browsing by Author "Dalveren,Y."

Now showing 1 - 12 of 12

Citation - Scopus: 1
An Approach for Identifying the Likelihood of an Irregular Terrain Profile Being a Multipath Scattering Center in Emitter Localization
(Association for Computing Machinery, 2017) Dalveren,Y.; Kara,A.; Department of Electrical & Electronics Engineering
In a single-receiver source localization scenario, pulses radiated from an emitting source (emitter) are reradiated from distributed points over the irregular terrain due to the diffuse scattering. Obviously, diffuse scattering may be occurred at anywhere over irregular terrains in dense scattering environments. Hence, a particular region from which the multipath pulses are scattered over the irregular terrain can be taken as a scattering center. In fact, a multipath scattering center may be approximated as multiple reflection points visible to the receiver. For this reason, an uncertainty in location of multipath scattering centers is expected. However, as proposed in this study, the likelihood of a particular region from which the multipath pulses are scattered may be identified if digital data of the irregular terrain, positions of the receiver and the transmitter, and Angle of Arrival (AOA) of the multipath are provided. In this context, this study attempts to provide an approach for identifying the likelihood of a particular region being a scattering center over the irregular terrain. To this end, Geometric Optics (GO)-based wave propagation principles are exploited to estimate path loss that would a basis for estimating likelihoods. Simulations are performed to illustrate the effectiveness of the proposed approach. This study aims to make significant contribution to an ongoing research on passive localization of radar emitters by exploiting multipath in dense scattering environments. © 2017 Association for Computing Machinery.
Citation - Scopus: 8
Cognitive Radio and Its Applications in the New Trend of Communication System: a Review
(Institute of Electrical and Electronics Engineers Inc., 2022) Al-Sudani,H.; Thabit,A.A.; Dalveren,Y.; Department of Electrical & Electronics Engineering
Spectrum efficiency decay due to high demand for high data rate and growing technologies, tens of billions of connected devices need to provide by the services wirelessly causing a sharp drop in spectral efficiency and high-power consumption. The software-defined technologies represent one of the most important enabling keys to 5G and beyond networks, which designed to host all emerging technologies in heterogeneous networks. Cognitive radio (CR) is a software-defined radio (SDR) and a magical tool to relieve spectrum scarcity and reduce the consumed power for communication. This paper surveys the detection techniques integrated with artificial neural networks (ANN) in heterogeneous networks to address a future work to accelerate the establishment of reconfigurable software-defined technologies and to succor the spectrum. It is found that wireless sensor network (WSN) and the internet of things (IoT) are expected to be the most influencers of the spectrum's solidity which have led the authors to conclude interesting future work. © 2022 IEEE.
Citation - Scopus: 4
Comparative Analysis of Tdoa-Based Localization Methods in the Presence of Sensor Position Errors
(Institute of Electrical and Electronics Engineers Inc., 2017) Dalveren,Y.; Kara,A.; Department of Electrical & Electronics Engineering
It is widely known that localization of emitters can be efficiently achieved by time difference of arrival (TDOA) techniques in a multiple sensor system. Several studies have been proposed in the literature to improve the localization accuracy of TDOA techniques. Among these, very few of them have considered the error in the sensor positions although the accuracy of localization is very sensitive to sensor position errors. In this study, existing TDOA-based localization methods in the presence of sensor position errors are briefly discussed, and then they are comparatively analyzed for specific scenarios. To this end, simulations are performed to compare the localization accuracy of the methods, specifically, with high level of sensor positional errors. It is intended to decide an efficient and robust estimator to be used for an ongoing research on passive localization of radar emitters in dense scattering environments. © 2017 IEEE.
Citation - WoS: 2
Citation - Scopus: 4
Convolutional Neural Network-Based Vehicle Classification in Low-Quality Imaging Conditions for Internet of Things Devices
(Multidisciplinary Digital Publishing Institute (MDPI), 2023) Maiga,B.; Dalveren,Y.; Kara,A.; Derawi,M.; Department of Electrical & Electronics Engineering
Vehicle classification has an important role in the efficient implementation of Internet of Things (IoT)-based intelligent transportation system (ITS) applications. Nowadays, because of their higher performance, convolutional neural networks (CNNs) are mostly used for vehicle classification. However, the computational complexity of CNNs and high-resolution data provided by high-quality monitoring cameras can pose significant challenges due to limited IoT device resources. In order to address this issue, this study aims to propose a simple CNN-based model for vehicle classification in low-quality images collected by a standard security camera positioned far from a traffic scene under low lighting and different weather conditions. For this purpose, firstly, a new dataset that contains 4800 low-quality vehicle images with 100 × 100 pixels and a 96 dpi resolution was created. Then, the proposed model and several well-known CNN-based models were tested on the created dataset. The results demonstrate that the proposed model achieved 95.8% accuracy, outperforming Inception v3, Inception-ResNet v2, Xception, and VGG19. While DenseNet121 and ResNet50 achieved better accuracy, their complexity in terms of higher trainable parameters, layers, and training times might be a significant concern in practice. In this context, the results suggest that the proposed model could be a feasible option for IoT devices used in ITS applications due to its simple architecture. © 2023 by the authors.
Citation - Scopus: 1
Development of a Digital Communications Course Enriched by Virtual and Remote Laboratory Tools
(2011) Kara,A.; Kara, Ali; Cagiltay,N.; Çağıltay, Nergiz; Dalveren,Y.; Dalveren, Yaser; Kara, Ali; Çağıltay, Nergiz; Dalveren, Yaser; Department of Electrical & Electronics Engineering; Software Engineering; Software Engineering; Department of Electrical & Electronics Engineering; Software Engineering
Digital communications is a basic concept for rapidly growing fields of Electrical, Computer and Electronics Engineering like wireless and mobile communication systems, radar and electronic warfare, telemetry and many signal processing techniques. A re-designed digital communications course with ICT (Information and Communication Technologies) based diverse tools including matlab assignments, remote experiments and interactive simulators is described in this study. First, the objectives of the course, learning outcomes and evaluation methods are described. The re-designed course is offered in the last semester at Atilim University, and performance increase in students is compared with the previous year's offering, and by evaluating the course on a topic-based approach. © 2011 IEEE.
Citation - Scopus: 2
An Experimental Study Towards Examining Human Body Movements in Indoor Wave Propagation at 18-22 Ghz
(Institute of Electrical and Electronics Engineers Inc., 2018) Alabish,A.; Kara,A.; Dalveren,Y.; Department of Electrical & Electronics Engineering
As 5G communication may use Millimeter waves (mmWave) bands, it is necessary to evaluate short-range indoor links from the link blockage point of view. This paper presents some initial studies for characterizing effects of human body movements on short range indoor links at 18-22 GHz. Firstly, measurement system is described, and then, calibration measurements along with initial results of the impact of human body movement on the channel are presented for some scenarios. To the best of our knowledge, this study is the first to experimentally examine the effects of human body movements at this band. Yet, as this study constitutes a part of an ongoing research, further results will be anticipated to present the effects of objects over and around the link on the directional propagation at mmWave bands (28-30 GHz). © 2018 IEEE.
An Experimental Study Towards Examining Human Body Movements in Indoor Wave Propagation at 18-22 Ghz
(Institute of Electrical and Electronics Engineers Inc., 2018) Alabish,A.; Kara,A.; Dalveren,Y.; Department of Electrical & Electronics Engineering
As 5G communication may use Millimeter waves (mmWave) bands, it is necessary to evaluate short-range indoor links from the link blockage point of view. This paper presents some initial studies for characterizing effects of human body movements on short range indoor links at 18-22 GHz. Firstly, measurement system is described, and then, calibration measurements along with initial results of the impact of human body movement on the channel are presented for some scenarios. To the best of our knowledge, this study is the first to experimentally examine the effects of human body movements at this band. Yet, as this study constitutes a part of an ongoing research, further results will be anticipated to present the effects of objects over and around the link on the directional propagation at mmWave bands (28-30 GHz). © 2018 IEEE.
Internet-Of Smart Transportation Systems for Safer Roads
(Institute of Electrical and Electronics Engineers Inc., 2020) Derawi,M.; Dalveren,Y.; Cheikh,F.A.; Department of Electrical & Electronics Engineering
From the beginning of civilizations, transportation has been one of the most important requirements for humans. Over the years, it has been evolved to modern transportation systems such as road, train, and air transportation. With the development of technology, intelligent transportation systems have been enriched with Information and Communications Technology (ICT). Nowadays, smart city concept that integrates ICT and Internet-of-Things (IoT) have been appeared to optimize the efficiency of city operations and services. Recently, several IoT-based smart applications for smart cities have been developed. Among these applications, smart services for transportation are highly required to ease the issues especially regarding to road safety. In this context, this study presents a literature review that elaborates the existing IoT-based smart transportation systems especially in terms of road safety. In this way, the current state of IoT-based smart transportation systems for safer roads are provided. Then, the current research efforts undertaken by the authors to provide an IoT-based safe smart traffic system are briefly introduced. It is emphasized that road safety can be improved using Vehicle-to-Infrastructure (V2I) communication technologies via the cloud (Infrastructure-to-Cloud - I2C). Therefore, it is believed that this study offers useful information to researchers for developing safer roads in smart cities. © 2020 IEEE.
Citation - Scopus: 37
Internet-Of Smart Transportation Systems for Safer Roads
(Institute of Electrical and Electronics Engineers Inc., 2020) Derawi,M.; Dalveren,Y.; Cheikh,F.A.; Department of Electrical & Electronics Engineering
From the beginning of civilizations, transportation has been one of the most important requirements for humans. Over the years, it has been evolved to modern transportation systems such as road, train, and air transportation. With the development of technology, intelligent transportation systems have been enriched with Information and Communications Technology (ICT). Nowadays, smart city concept that integrates ICT and Internet-of-Things (IoT) have been appeared to optimize the efficiency of city operations and services. Recently, several IoT-based smart applications for smart cities have been developed. Among these applications, smart services for transportation are highly required to ease the issues especially regarding to road safety. In this context, this study presents a literature review that elaborates the existing IoT-based smart transportation systems especially in terms of road safety. In this way, the current state of IoT-based smart transportation systems for safer roads are provided. Then, the current research efforts undertaken by the authors to provide an IoT-based safe smart traffic system are briefly introduced. It is emphasized that road safety can be improved using Vehicle-to-Infrastructure (V2I) communication technologies via the cloud (Infrastructure-to-Cloud - I2C). Therefore, it is believed that this study offers useful information to researchers for developing safer roads in smart cities. © 2020 IEEE.
Citation - Scopus: 6
A Mini-Review on Radio Frequency Fingerprinting Localization in Outdoor Environments: Recent Advances and Challenges
(Institute of Electrical and Electronics Engineers Inc., 2022) Dogan,D.; Dalveren,Y.; Kara,A.; Department of Electrical & Electronics Engineering; Mechatronics Engineering
A considerable growth in demand for locating the source of emissions in outdoor environments has led to the rapid development of various localization methods. Among these, RF fingerprinting (RFF) localization has become one of the most promising method due to its unique advantages resulted from the recent developments in machine learning techniques. In this short review, it is aimed to assess the existing RFF methods in the literature for outdoor localization. For this purpose, firstly, the current state of RFF localization methods in outdoor environments are overviewed. Then, the main research challenges in the development of RFF localization are highlighted. This is followed by a brief discussion on the open issues in order to give future research directions. Furthermore, the research efforts currently undertaken by the authors are briefly addressed. © 2022 IEEE.
Citation - Scopus: 8
Multipath Exploitation in Emitter Localization for Irregular Terrains
(Czech Technical University, 2019) Dalveren,Y.; Kara,A.; Department of Electrical & Electronics Engineering
Electronic Support Measures (ESM) systems have many operational challenges while locating radar emitter's position around irregular terrains such as islands due to multipath scattering. To overcome these challenges, this paper addresses exploiting multipath scattering in passive localization of radar emitters around irregular terrains. The idea is based on the use of multipath scattered signals as virtual sensor through Geographical Information System (GIS). In this way, it is presented that single receiver (ESM receiver) passive localization can be achieved for radar emitters. The study is initiated with estimating candidate multipath scattering centers over irregular terrain. To do this, ESM receivers' Angle of Arrival (AOA) and Time of Arrival (TOA) information are required for directly received radar pulses along with multipath scattered pulses. The problem then turns out to be multiple-sensor localization problem for which Time Difference of Arrival (TDOA)-based techniques can easily be applied. However, there is high degree of uncertainty in location of candidate multipath scattering centers as the multipath scattering involves diffuse components over irregular terrain. Apparently, this causes large localization errors in TDOA. To reduce this error, a reliability based weighting method is proposed. Simulation results regarding with a simplified 3D model are also presented. © 2019 RADIOENGINEERING.
Citation - Scopus: 7
Spectrum Analysis of Parabolic Range Gate Pull-Off (rgpo) Signals;
(Institute of Electrical and Electronics Engineers Inc., 2015) Ozturk,M.T.; Dalveren,Y.; Kara,A.; Department of Electrical & Electronics Engineering
Digital Radio Frequency Memory (DRFM) is a method that is used to capture radar threat signals, and retransmit them by changing their parameters in order to deceive or manipulate radar threats. Range gate pull-off (RGPO) technique is widely used in DRFM methods. RGPO can be either linear or parabolic RGPO according to the applied pull-off function. In this study, firstly, analytical derivations for temporal and spectral analysis of discrete form of linear and parabolic RGPO signals are presented. Then, various scenarios dependent on the parameters of pull-off function are created. Finally, simulation results regarding the scenarios are presented. © 2015 IEEE.