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WOS: 000533508400007 This study aimed to evaluate the protective role of paricalcitol, a vitamin D analog, against hazardous effects of 1800MHz radiofrequency (RF) radiation on the skin of male Wistar albino rats exposed one h/day for 4weeks. The maximum specific absorption rate was calculated as 0.0042W/kg. Superoxide dismutase and catalase activity, collagen bundle thickness, breaking force, energy, and stress were decreased, while malondialdehyde level and mast cell number were increased. The exposure to 1800-MHz RF radiation caused a reduction in skin biomechanical quality through oxidative stress and mast cell activation. The administration of paricalcitol caused a significant improvement. Research Fund of Mersin University in TurkeyMersin University [2017-1-TP2-2214] This work was supported by the Research Fund of Mersin University in Turkey [grant number BAP, 2017-1-TP2-2214].

With the widespread use of smart phones, to investigate the effects of electromagnetic waves emitted from these devices on human health has become more important. For this purpose, the specific absorption rate (SAR) values were calculated by numerical simulations using a computational smartphone model which contains third generation (3G) and fourth generation communication (4G) systems antennas and computational human models. In addition, separate calculations were made for adult male, adult female and child computational human models, and age and gender related differences were determined. SAR calculations were performed at 1.8 GHz and 2.4 GHz frequencies, and the SAR values of brain, skin and bone tissues of the head were compared.

Rapid development in mobile phone technologies increase the average mobile phone usage duration. This increase also triggers exposure to radiofrequency radiation (RF), which is a risk factor for the health. In this study, it was aimed to investigate the effect of mobile phone working with LTE-Advanced Pro (4.5 G) mobile network on the optic nerve, which is responsible for the transmission of visual information.Thirty-two rats divided into two groups as control (no RF, sham exposure) and experimental (RF exposure using a mobile phone with LTE-Advanced Pro network; 2 hours/day, 6 weeks). The visual evoked potential (VEP) was recorded and determined amplitudes and latencies of VEP waves. Optic nerve malondialdehyde level, catalase and superoxide dismutase activities were determined. Furthermore, ultrastructural and morphometric changes of optic nerve were evaluated.In VEP recordings, the mean VEP amplitudes of experimental group were significantly lower than control group. In ultrastructural evaluation, myelinated nerve fibres and glial cells were observed in normal histologic appearance both in sham and experimental group. However, by performing morphometric analysis, in the experimental group, axonal diameter and myelin thickness were shown to be lower and the G-ratio was higher than in the sham group. In the experimental group, malondialdehyde level was significantly higher and superoxide dismutase and catalase activities were significantly lower than sham group. There was a high correlation between VEP wave amplitudes and oxidative stress markers.Findings obtained in this study support optic nerve damage. These results point out an important risk that may decrease the quality of life.

In this study, available spectrum parts in GSM900, LTE800, LTE900, GSM1800, LTE1800, UMTS2100 and LTE2600 were determined. The measurement campaigns were performed at 115 different locations in Samsun city center at the most active time of a day using RF Explorer 6G Combo analyzer device. The spectrum utilization rates were determined using energy detection technique (EDT), and average spectrum occupancy technique (ASOT). The thresholds were chosen manually as -40, -45, -50, -55, -60, -65, -70, -75 dBm, and as 10-dB above the noise floor, as recommended by International Telecommunication Union (ITU), and spectrum utilization was evaluated through EDT and ASOT. Obtained results show that at most of the measurement locations spectrum occupancy percentages calculated via EDT and ASOT very close to each other. Based on the results UMTS2100 band showed the highest average spectrum occupancy i.e. 33.91% and the overall average spectrum occupancy rate was found to 22.72%. Additionally, at 50% of the measurement locations occupancy percentage was below 33% for all services. The average occupancy over GSM900 band was between 0,87% - 66.61% according to the predetermined threshold. It was also found that the bands LTE1800 and LTE2600 were mostly occupied for the thresholds below -60 dBm whereas the measured spectrum was mostly vacant for -40 dBm. This led us to infer that there is a great potential for share some of UHF band for cognitive radio applications and future 5G systems.

The nervous system is an important target of radiofrequency (RF) radiation exposure since it is the excitable component that is potentially able to interact with electromagnetic fields. The present study was designed to investigate the effects of 1,800 MHz RF radiation and the protective role of paricalcitol on the rat sciatic nerve. Rats were divided into four groups as control, paricalcitol, RF, and RF + paricalcitol. In RF groups, the rats were exposed to 1,800 MHz RF for 1 h per day for 4 weeks. Control and paricalcitol rats were kept under the same conditions without RF application. In paricalcitol groups, the rats were given 0.2 μg/kg/day paricalcitol, three times per week for 4 weeks. Amplitude and latency of nerve compound action potentials, catalase activities, malondialdehyde (MDA) levels, and ultrastructural changes of sciatic nerve were evaluated. In the RF group, a significant reduction in amplitude, prolongation in latency, an increase in the MDA level, and an increase in catalase activity and degeneration in the myelinated nerve fibers were observed. The electrophysiological and histological findings were consistent with neuropathy, and the neuropathic changes were partially ameliorated with paricalcitol administration. Bioelectromagnetics. 39:631-643, 2018. © 2018 Wiley Periodicals, Inc.

WOS: 000457609400012 PubMed: 30007352 As a result of the drastic increase in the number of mobile device users, there is considerable public debate about possible health hazards especially due to base stations and Wi-Fi access points. For this reason, in this study the effects of the number of users in a base station and wireless fidelity (Wi-Fi) access point on electric field strength (E) levels were investigated using real-time measurements. Two-stage E measurements were performed on Ondokuz Mayis University's (OMU) Kurupelit Campus with a PMM-8053 and SRM-3006 electromagnetic field (EMF) meter. In the first stage, 24-h measurements were performed with PMM-8053 at the location where the maximum E was measured and from which the busiest times of the day were then determined. The relationship among band selective E values was assessed using the number of users per minute provided by three cellular system operators for the location. Upper and lower bounds of E according to the number of users were calculated, and then an empirical model that helps calculate the E of medium with 86% accuracy was proposed. In the second stage, the effect of the number of users in a Wi-Fi access point on E level was investigated. For this purpose, the measurement environment was set as including one Wi-Fi access point with needed measurement devices. The number of users was increased as per user per minute. The number of users was validated with the data obtained from OMU IT Department. Using the measurement result, a model with a 96% accuracy between the E value in the environment and the number of users accessing the Wi-Fi system is proposed. With the use of these models, E level in the medium can be determined without using any EMF meters, thus precautions can be taken to stay within regulatory limits.

In parallel with technological developments wireless systems have becomeindispensable parts our daily life, and dense use of these systems the numberof base stations in environment and thus the exposed electromagnetic radiation(EMR) levels has also increased. Accurate measurement, evaluation and controlof compliance with established limit values of the exposed EMR levels hasbecome even more important than before in terms of human/vital health. Inaddition, due to the increase in EMR resources, it is essential to develop themodel that will be used to determine the future values of the EMR levels. Therefore,in this study, 24 hour electric field strength (E) measurements were carriedout in a shopping mall in order to determine the level of EMR exposure andtheir statistical properties were determined. Then the time series analysis isapplied to the measurement results and the change of the E level in theenvironment is modeled by moving averages and the E value one day later isestimated based on this model. It has been determined that the estimated Evalue is very close to the real values. In addition, by using the proposedmodel, the future values of E in an environment can be estimated and thesevalues can be used for environments with similar conditions., Teknolojikgelişmelerle birlikte hayatımızın vazgeçilmez unsurları haline gelen kablosuzsistemlerin yoğun kullanımı nedeniyle yaşam alanlarımızdaki Baz istasyonusayısı ve buna bağlı olarak maruz kalınan elektromanyetik radyasyon (EMR)seviyeleri de artmıştır. Maruz kalınan EMR seviyelerinin doğru bir biçimdeölçülmesi, değerlendirilmesi ve belirlenen limit değerlere uygunluğunun kontroledilmesi insan/canlı sağlığı açısından eskisinden daha da önemli halegelmiştir. Ayrıca EMR kaynaklarının her geçen gün artması nedeniyle, EMRseviyelerinin gelecek değerlerinin belirlenmesinde kullanılacak modelingeliştirilmesi elzemdir. Bu nedenle bu çalışmada, maruz kalınan EMR seviyesinibelirlemek üzere insanların yoğun olarak bulunduğu bir alışveriş merkezinde birhafta süresince 24 saatlik elektrik alan şiddeti (E) ölçümlerigerçekleştirilmiş ve istatistiksel özellikleri belirlenmiştir. Ardından ölçümsonuçlarına zaman serisi analizi uygulanarak ortamdaki E seviyesinin değişimihareketli ortalamalar ile modellenmiş ve bir gün sonraki E değeri bu modeledayanılarak tahmin edilmiştir. Sonuçlardan tahmin edilen E değerinin gerçeğeoldukça yakın olduğu belirlenmiştir. Ayrıca önerilen modelin kullanımı ile birortamdaki E’nin gelecekte alabileceği değerler belirlenebilir ve bu değerlerbenzer koşullardaki ortamlar için de kullanılabilir.

WOS: 000433222000013 PubMed: 29237074 In this study, in order to evaluate the exposed radiofrequency electromagnetic field (RF-EMF) levels, and to control their compliance with the limits determined by International Commission on Non-Ionizing Radiation Protection (ICNIRP), extensive short-term/band-selective and long-term RF-EMF measurements were conducted at 92 primary and secondary schools in the Ilkadim district of Samsun/Turkey. The measurements were performed once each in May, June, October and December in 2016, using the PMM-8053 EMF meter. It was seen from the measurement results that the maximum average electric field strength (E-avg) was recorded, 2.34 V/m, in October, when students were at school. It was concluded from the measurement results that the measured E-avg levels recorded at 92 schools were below the limits determined by ICNIRP. According to the band-selective measurement results performed using a Narda SRM-3006 EMF meter, the five main electric field strength (E) sources that had the most contribution in total E were LTE800, GSM900, GSM1800, UMTS2100 and WLAN services. With the use of these main E sources, an empirical model was then proposed that helps to determine the total E with 99.6% accuracy. It was also concluded from the long-term broadband measurement result that the number of active users affected the total E in the medium directly, and that the measured E levels were significantly higher in daytime than those of recorded in night-time. In the final stage of the study, all measurement results were transferred on scaled color maps. The use of these maps helped to determine and maintain control on the levels of RF-EMF exposure at schools using, or intending to install, such systems, and also to take measures for future precautions. Ondokuz Mayis UniversityOndokuz Mayis University; Graduate Thesis Support Program [PYO. MUH.1904.15.023] This study is supported by Ondokuz Mayis University Research Fund, Graduate Thesis Support Program, Project No: PYO. MUH.1904.15.023.

6th International Conference on Electrical and Electronics Engineering (ICEEE) -- APR 16-17, 2019 -- Istanbul, TURKEY WOS: 000494805700056 Road safety is a concern of all authorities. One of the most important safety concerns is excessive speed which results in accidents, injuries, death, as well as damage in public property. Therefore, the imposition of automatic speed is essential and important in municipality's arsenal to prevent and combat excessive speed. The speed control system that we used in this project depends on the ultrasonic radar. Where this radar unit is capable of tracking multiple vehicles together across multiple tracks. The system consists of an ultrasonic sensor, an Arduino board, and a webcam. Speed and location of vehicles are determined accurately by using ultrasonic sensor, and the distance is calculated over a simple period of time. The vehicles like ambulances were excluded from the speed limit because the speed is necessary in this case to save lives. In the proposed system, if the speed of the car reaches 95% of the specified speed limit of the road, the system will warn the driver by sending a light packet means will be punished if the speed exceeds. If the vehicle exceeds the predefined speed, the system will take a high-resolution digital image of the vehicle and the license plate. The image taken will be presented as a guide to the competent authorities as evidence of the detailed information (location of the event, maximum speed, time, date and speed of the car). By using this prototype speed control system, speed monitoring can be done through sensors, in efficient and cheaper way.

This study aims to determine the mapping rule for signal-to-interference ratio (SIR) to channel quality indicator (CQI) based on DC-HSDPA real field measurements. The measurements were performed using the TEMS Investigation Tool at 85 different propagation mediums. The measurement results showed that the SIR-to-CQI mapping methods in the literature were insufficient to characterize actual radio environments; thus, proposal of a new empirical SIR-to-CQI mapping rule was aimed. This rule provides substantially better performance than the existing methods, and with this rule CQI can be generated from SIR with an accuracy of around 90% for DC-HSDPA systems. © TUBITAK.

International Conference on Electrical and Computing Technologies and Applications (ICECTA) -- NOV 19-21, 2019 -- Ras Al Khaimah, U ARAB EMIRATES WOS: 000529375800067 The paper deals with an analysis of multipath components (MPCs) propagation in the 60 GHz band based on frequency-domain channel measurements. The main goal of this work is to examine the power and the RMS delay spread distributions and their mutual dependence for a static urban environment. The paper evaluates the reflective properties of the surrounding objects and the effect of co-polarized and cross-polarized transmitting and receiving antennas on the above distributions. It is shown that some relations between the received signal power and the RMS delay spread can be found particularly for the co-polarized antennas, but that they are only of limited validity. The presented analyses show very good reflective properties of the asphalt surface and demonstrate them by the small difference between the direct and the reflected MPC magnitudes. Czech Science FoundationGrant Agency of the Czech Republic [17-27068S]; National Sustainability Program [LO1401] The research described in this paper was financed by the Czech Science Foundation, Project No. 17-27068S, and by the National Sustainability Program under grant LO1401. For the research, the infrastructure of the SIX Center was used.

26th Telecommunications Forum (TELFOR) -- NOV 20-21, 2018 -- Belgrade, SERBIA WOS: 000459714200109 SAR is a value corresponding to the energy absorbed by human tissue when exposed to radiation. In this study, the SAR value caused by a base station operating at 900 MHz and 1800 MHz independently of the mobile phones was investigated by means of the signal generator that represent the base station. The calculations are evaluated by simulations through the CST STUDIO program for 900 MHz and 1800 MHz, and compared with the actual measurements results that performed at a standardized SAR laboratory. In order to determine the effect of the same SAR value of SAM phantom on human tissue Gustav biomodel was used. The SAM calculations were repeated for Gustav and the 1g and 10g SAR values for 900 MHz and 1800 MHz were calculated. At 900 MHz the SAR value of 0.175244 W / kg obtained in the SAR laboratory was successfully simulated with a SAR value of 0.176615 W / kg obtained in the simulation medium. At 1800 MHz The SAR value of 1.748332 W / kg obtained in the SAR laboratory was successfully simulated with a SAR value of 1.74521 W / kg obtained in the simulation medium. These SAR values correspond to about 13.75 V / m for 900 MHz and 35.50 V / m for 1800 MHz of absorbed electromagnetic field in the phantoms whose dielectric properties are approximately the same. Telecommunicat Soc, Univ Belgrade, Sch Elect Engn, IEEE Serbia & Montenegro COM Chapter, Telekom Serbija a d, Minist Trade Tousim & Telecommunicat, VLATACOM d o o, ERICSSON, IRITEL a d BEOGRAD, MAKSNET Telekomunikacije, Minist Educ Sci & Technol Dev, MDS, Publ PTT Enterprise Srbija, Republ Agcy Elect Communicat Serbia, ROAMING Networks, TERI Engn, VIP Mobile, CISCO, IEEE Serbia & Montenegro Sect, KAPSCH, Serbian Natl Register of Internet Domain Names, IEEE Commun Soc Serbia & Montenegro Chapter, IEEE Reg 8, mts Ondokuz Mayis University Research Fund, Graduate Thesis Support Program; [PYO.MUH.1904.17.017] The study is supported by Ondokuz Mayis University Research Fund, Graduate Thesis Support Program, and Project No: PYO.MUH.1904.17.017.

The nervous system is an important target of radiofrequency (RF) radiation exposure since it is the excitable component that is potentially able to interact with electromagnetic fields. The present study was designed to investigate the effects of 1,800 MHz RF radiation and the protective role of paricalcitol on the rat sciatic nerve. Rats were divided into four groups as control, paricalcitol, RF, and RF + paricalcitol. In RF groups, the rats were exposed to 1,800 MHz RF for 1 h per day for 4 weeks. Control and paricalcitol rats were kept under the same conditions without RF application. In paricalcitol groups, the rats were given 0.2 μg/kg/day paricalcitol, three times per week for 4 weeks. Amplitude and latency of nerve compound action potentials, catalase activities, malondialdehyde (MDA) levels, and ultrastructural changes of sciatic nerve were evaluated. In the RF group, a significant reduction in amplitude, prolongation in latency, an increase in the MDA level, and an increase in catalase activity and degeneration in the myelinated nerve fibers were observed. The electrophysiological and histological findings were consistent with neuropathy, and the neuropathic changes were partially ameliorated with paricalcitol administration. Bioelectromagnetics. 39:631-643, 2018. © 2018 Wiley Periodicals, Inc.

WOS: 000451598500012 PubMed: 30028652 Aim: To investigate the inflammatory effect and testicular damage on rats exposed to low level of electromagnetic fields (EMF) at 2.45 GHz microwave radiation. Methods: Twenty two Wistar rats were divided into two groups. Group 1 was the control group and not exposed to EMF. Group 2 was exposed to low level EMF (average E-field 3.68 +/- 0.36 V/m, whole body average SAR, 0.0233 W/kg, in 10 g tissue) at 2.45 GHz for 1 hour/day for 30 consecutive days. At the end of the study, interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-32 (IL-32), C-reactive protein (CRP) were measured in rat serum and IL-6, IL-10, IL-32 were measured in rat testis tissue. Furthermore, testicular tissues were evaluated histopathologically in terms of spermatogenesis and coagulation necrosis. Results: Serum IL-6 and CRP levels were found to be significantly different in the study group compared to the control group (p < .05), but no significant difference was found in serum IL-10, IL-32 levels and testis tissue IL-6, IL-10, IL-32 levels compared to the control group (p > .05). On the other hand, histopathological evaluation of testicular tissue revealed a significant difference in necrosis and spermatogenesis when compared with the control group (p < .05). Conclusions: It may be concluded that low level EMF at 2.45 GHz increases inflammation and testicular damage and negative impact on male reproductive system function.

4th International Electromagnetic Compatibility Conference (EMC Turkiye) -- SEP 24-27, 2017 -- Ankara, TURKEY WOS: 000425269300016 Technological improvements and dense use of wireless systems has led to an increase in exposed electromagnetic radiation (EMR) levels in recent years. The effects of these EMRs on the population have not been completely characterized despite intense research on this topic. For this reason accurate evaluation of EMR levels in the environment have become essential. Therefore, this study aims to determine the electric field strength (E) levels on Samsun Light Rail System which can board around 90.000 passengers per day. To reach this goal; extensive E measurements were conducted on trams during the journey of total 36 stops for one week long using PMM 8053 EMR meter, and the E with a sampling period of 1 second was recorded. It is seen from the measurement results that the highest E is 5.44 V/m while the highest mean E is 0.40 V/m. Furthermore, contribution of E sources in total E determined on the basis of band selective measurements via SRM 3006 EMR meter, and the main E source is decided as cellular systems. In addition to that, the signal strengths of three existing operators for cellular systems were measured by using "NetMonitor" application. 24-27 Sept. 2017, , Turkey

2017 International Artificial Intelligence and Data Processing Symposium (IDAP) -- SEP 16-17, 2017 -- Malatya, TURKEY WOS: 000426868700062 In this study, the effect of the number of users in a Wi-Fi access point on signal strength and throughput is investigated. For this purpose, measurement environment was set as including one Wi-Fi access point, needed measurement devices and 70 users. The number of users was increased as per user/per second. Each user was asked to download the same 300 MB data file from the certain WEB page. In the meanwhile, the signal strength was measured using android based "Wi-Fi Analyzer" application and the data traffic on the Wi-Fi modem was tracked. The changes in Wi-Fi channel usage and channels' signal strengths depending on the increment in the number of users were investigated. The number of users and throughput rates were validated with the data obtained from Ondokuz Mayis University IT Department. It is seen from the results that the signal strength may vary between -80 dBm and -46 dBm depending on the number of users. The sudden changes have occurred in throughput rates as a result of the number of users connected to the access point at the same time. It is also determined from the measurement results that the maximum throughput is 20.26 Mbps while the mean is 10.07 Mbps, and the maximum allowable number of users is 64. IEEE Turkey Sect, Anatolian Sci

40th International Conference on Telecommunications and Signal Processing (TSP) -- JUL 05-07, 2017 -- Barcelona, SPAIN WOS: 000425229000058 As a result of the enormous increase in usage of wireless systems; electromagnetic radiation (EMR) sources in residential areas as well as the exposed EMR levels has increased significantly. Therefore this study aims to determine the exposed E levels and characterize the electromagnetic environment on the basis of long term (24 hours) E measurements conducted at five different home environments. The measurements were collected using PMM 8053 EMR meter in band from 100 kHz to 3 GHz, and the electric field strength (E) was recorded. The measurement results show that the E originating from the base stations change significantly within a day, and the highest E is 6.21 V/m and the highest mean E is 3.59 V/m. Analysis of 24 hour measurements so as to division of a day into four equal parts show that afternoon and evening E levels are comparatively higher than those recorded during morning and night. Morning E level increases by 80.61% compared to night. At the end of the study to characterize the measured E levels with a distribution; fitting methods are applied to measured data. Since a Weibull distribution yield the lowest NRMSE; appears to be a candidate for a representation of the distribution of the measured E levels.

2017 International Artificial Intelligence and Data Processing Symposium (IDAP) -- SEP 16-17, 2017 -- Malatya, TURKEY WOS: 000426868700126 This study aims to determine total electric field strength (E) levels and its main sources in Samsun city center. To reach this goal extensive E and band selective E measurements were performed using Narda SRM 3006. The measurements were collected on the busiest streets of Samsun city during a journey of more than two hours on a vehicle moving with a certain velocity. On the basis of over 700 measurements E and E sources within the band were determined. It is seen from the results that the main sources of E were the base stations that operates at GSM900, GSM1800 and UMTS frequency bands. Because of difficulties encountered in band selective measurements (need for specific and expensive meters); a model that helps to obtain the three band selective Es in terms of E was proposed, and its performance was improved by using multilayer perceptron (MLP) artificial neural network system. With the use of this model; E levels of the three main sources can be determined from E in the environment up to 95% accuracy. IEEE Turkey Sect, Anatolian Sci

5th International Conference on Radiation and Applications in Various Fields of Research, RAD 2017 -- 12 June 2017 through 16 June 2017 -- -- 142103 In parallel with technological developments, cellular systems and therefore base stations have begun to take up more space in our daily lives. Since each base station behaves like a radiofrequency electromagnetic field (RF-EMF) source, this increase in base stations leads to an increase in the value of RF-EMF. Therefore, it is very important to measure and evaluate the RF-EMF emitted from the base stations regarding its influence on human health. In this study, RF-EMF measurements were taken in ten different locations (schools, hospitals, homes, shopping malls, etc.) during 24 hours to investigate the time/location dependent changes in RF-EMF. For the measurement, the PMM8053 EMF meter measuring the total RF-EMF in the frequency range of 100 kHz-3 GHz was used, the highest electric field strengths (Emax) in the environment and the average electric field strengths (Eavg) were recorded. The measurement results show that the electric field strengths (E) originating from the base stations change significantly depending on the measurement location and time (usage intensity). The changes in E measured during the daytime in the home environment are softer, while for workplaces they are sharper due to opening/closing time. It is seen from the measurements that the highest Emax is 7.88V/m and the highest Eavg is 2.95V/m. In order to analyze the 24-hour measurements more precisely, four specific time intervals such as morning (6am-12am), afternoon (12am-6pm), evening (6pm-12pm) and night (12pm-6am) were selected. The mean E value for morning is 1.55V/m, while they are 1.94V/m, 1.48V/m and 1.16V/m for afternoon, evening and night respectively. E level at night increases by 67.2% compared to in the afternoon. At the end of the study, daily variations of E values were examined and empirical models were proposed using curve fitting methods. With the use of these models, the E in the environment can be predicted with an accuracy of up to 95%. © RAD Conference Proceedings. All rights reserved.

There has been a substantial growth in the use of mobile communication services over the last few years. As a result of this increase in the number of base stations, and electromagnetic (EM) exposure levels have become inevitable. Considering the public debate about possible health hazards caused by electric field strength (E), in this study, evaluating the effect of establishment of 4G systems on existing E levels is aimed. For this purpose; the total 536 E measurements were conducted in Samsun before and after 1 April 2016. It is seen from the measurements that maximum E ( E max ) is 6.32 V/m while the maximum average E ( E avg ) is 3.26 V/m which are both below the limits that are determined by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and Information and Communication Technologies Authority of Turkey ( ICTA). The results demonstrate that the deployment of 4G yielded up to 52.3% increase in E max while 12.5% in E avg values. Furthermore in order to determine the main E sources band selective E measurements are conducted and analysed. Analyses demonstrate that 65.6% of total E is caused by UMTS2100, 22.3% is produced by GSM900, 4.8% by GSM1800, 1.3 % by LTE800, and 6% is generated by devices that use the remaining frequency bands.

16th Mediterranean Microwave Symposium (MMS) -- NOV 14-16, 2016 -- Abu Dhabi, U ARAB EMIRATES WOS: 000392389200004 As a result of the growing usage of wireless devices and a large number of WLANs installations at schools; determining the exposure levels to students and staff from these systems has become more crucial than before. Since microwave radio links are used to provide connection between wireless devices, proper assessment of exposure to microwave emissions must be carried out. For this reason, in this study electromagnetic radiation (EMR) measurements were conducted at 92 different schools in Ilkadim district twice in 2016 using PMM 8053 EMR meter. The changes in and statistical properties of electric field strengths (E) are determined on the basis of these measurements. The maximum Es (E-max) are 5.39 V/m and 3.04 V/m for each measurement while the maximum average Es (E-avg) are 2.22 and 2.25 V/m. Even though the measured E levels are below the limits that are determined by the International Commission on Non-Ionizing Radiation Protection (ICNIRP); for providing a wide margin of protection and evaluating the health risks they may cause, regular control/measurement of exposed EMR levels is recommended. IEEE Microwave Theory & Tech Soc, IEEE Instrumentat & Measurements Soc, IEEE Antennas & Propagat Soc, IEEE Reg 8, IEEE UAE Sect, IEEE UAE MTT & IM Joint Soc Chapter, Abu Dhabi Convent Bur, TRANSCO, Keysight Motabaqah Research Fund of Ondokuz Mayis UniversityOndokuz Mayis University [PYO.MUH.1904.15.023] This study is supported by Research Fund of Ondokuz Mayis University (Project no. PYO.MUH.1904.15.023).

WOS: 000405898800004 PubMed: 27885087 As a result of the dense deployment of wireless devices and base stations, measuring and evaluating the electromagnetic (EM) exposure levels they emit have become important to human health especially if they exceed the limits defined in the standards. Base stations, Wi-Fi equipment and other electronic devices are used heavily, especially in densely crowded places like shopping centers. In this study, electric field strength (E) measurements were conducted at one of the largest shopping malls in Turkey. Broadband E measurements were performed using PMM 8053 EM field strength meter for 24 h a day for the duration of one week while frequency selective measurements were carried out with SRM-3006 EM field strength meter. It is concluded from the measurements that the mean measured total E in the band between 100 kHz and 3 GHz is 0.59 V/m while the maximum E is 7.88 V/m, which are both below the limit determined by International Commission on Non-Ionizing Radiation Protection. Evolutions show that E can increase by up to 55% during the daytime. Analyses demonstrate that 71.3% of total E is caused by UMTS2100, 16.3% is produced by GSM900, 6.2% by LTE, 3.5% by Wi-Fi, and 2.7% is generated by devices that use the remaining frequency bands. Based on the detailed statistical analysis of long-term E measurement results, it can be concluded that the measured E levels are not in normal distribution and that they are statistically different with respect to days. Furthermore, distribution of E can be best modeled with the non-parametric approach.

39th International Conference on Telecommunications and Signal Processing (TSP) -- JUN 27-29, 2016 -- Vienna, AUSTRIA WOS: 000390164000046 As a result of technological developments and consumers' demands give rise to an increase in the number of base stations day by day. Measuring and evaluating the exposed electromagnetic radiation (EMR) levels have become more substantial for human health especially in city centers where base stations are used densely. Thus, in this study, EMR measurements were conducted in two stages in Samsun city center. First, EMR measurements were performed using PMM 8053 for the appointed locations and time periods. Second, drive test measurements were done for much wider region through SRM-3006. It is concluded from the measurements that the maximum measured total electric field strength (E) in the band between 100 kHz -3 GHz is 7.32 V/m which is below the limits determined by ICNIRP. A detailed examination of band selective measurements demonstrate that the main EMR sources in Samsun city center are the base stations which use 900MHz, 1800MHz and 2100MHz frequency bands, and 2100MHz has the most contribution to total E with 70%. Furthermore, an empirical model that helps calculating the total E of medium through these three main EMR sources with 99% was proposed. IEEE Reg 8, IEEE Austria Sect, IEEE Czechoslovakia Sect, IEEE Czechoslovakia Sect SP CAS COM Joint Chapter, IEEE Croatia Sect, Communicat Chapter, Brno Univ Technol, Dept Telecommunicat, Budapest Univ Technol & Econ, Dept Telecommunicat & Media Informat, Karadeniz Tech Univ, Dept Elect & Elect Engn, W Pomeranian Univ Technol, Fac Elect Engn, VSB Tech Univ Ostrava, Dept Telecommunicat, Slovak Univ Technol, Inst Telecommunicat, Univ Ljubljana, Lab Telecommunicat, Czech Tech Univ Prague, Dept Telecommunicat Engn, Univ Osijek, Fac Elect Engn, Tech Univ Sofia, Fac Telecommunicat, Seikei Univ, Grad Sch & Fac Sci & Technol, Informat Networking Lab

24th Telecommunications Forum (TELFOR) -- NOV 22-23, 2016 -- Belgrade, SERBIA WOS: 000393491700037 In this study, available Television White Space (TVWS) spectrums were measured and evaluated in Samsun Turkey. The measurements were performed within 470 MHz -790 MHz band, at ten locations which are differently distanced from TV transmitter stations using software based RTL2832U-R820T frequency analyzer. In the measurements -40dB and -45dB above signals are considered. It is seen from the results that, frequency spectrum usage change depending on the distance from TV transmitter station, existence of Line of Sight (LOS) path and geographical features of measurement locations, and percentage of available TV space in Samsun city center varies between 5% and 62.5%. Approximately 7.5% increase in spectrum availability is achievable with the choice of lower reference value (i. e. -45dB). It is also concluded from the temporal measurement results that number of channels used may vary due to measurement time. With the use of these results the spectrum utilization in Samsun could be improved. Telecommunicat Soc, Univ Belgrade, Sch Elect Engn, IEEE Serbia & Montenegro COM Chapter, TELECOM SRBIJA a d, Minist Trade Turism & Telecommunicat, ERICSSON, IRITEL a d BEOGRAD, Kontriola letenja Srbije i Crne Gore SMATSA, Minist Educ Sci & Technol Dev, NOKIA, Public PTT Enterprise SRBIJA, Republ Agcy Elect Commun Serbia, Rohde&Schwarz, Roaming Networks, TERI Engn, VIP Mobile, VLATACOM d o o, IBIS Instruments, IEEE Serbia & Montenegro Sect, Serbian Natl Register Internet Domain Names, IMTEL Ccommun, IEEE Commun Soc, Serbia & Montenegro Chapter, IEEE Reg 8, IEEE, mts

22nd IEEE Signal Processing and Communications Applications Conference (SIU) -- APR 23-25, 2014 -- Karadeniz Teknik Univ, Trabzon, TURKEY WOS: 000356351400144 Increasing demand on higher data rates, makes multi carrier systems popular. Orthogonal frequency division multiplexing (OFDM), a form of multicarrier modulation, has been widely applied in wireless communication systems for major advantages. In order to obtain channel state information, and overcome multipath fading channel estimation must be performed in these systems. The channel estimation quality significantly depends on the pilot pattern. In this study, the relationship between the optimum pilot symbol interval that yields the minimum channel estimation mean squared error and coherence bandwidth, coherence time at 0,9 correlation is investigated in OFDM systems for different time and frequency selective channels. Different curve fitting methods are applied to data and performances are compared in terms of normalized root mean squared errors (NRMSE). Considering both simplicity and NRMSE; the optimum pilot symbol interval is calculated by cubic polynomial in frequency direction, and by quadratic polynomial in time direction. IEEE, Karadeniz Tech Univ, Dept Comp Engn & Elect & Elect Engn

8th International Conference on Electrical and Electronics Engineering (ELECO) -- NOV 28-30, 2013 -- Bursa, TURKEY WOS: 000333752200061 In orthogonal frequency division multiplexing (OFDM) systems, in order to overcome distortion caused by multipath fading, channel estimation is performed. Pilot symbol assisted channel estimation is effectual way to obtain channel state information. However, use of pilot symbols, leads overhead and the number of pilot symbols should be kept as minimum as possible. In this study, in order to evaluate the optimum pilot density, channel state information is obtained by using two dimensional (2-D) pilot based channel estimation. The analytical and simulated optimum pilot intervals in frequency and time direction are determined in terms of mean squared error (MSE). Then these intervals related to channel's coherence time (T-c) and bandwidth (B-c) at 0.9 correlation coefficient. It is seen from the results that by using approximately 2.4 pilot symbols per B-c,B-0.9, and per T-c,T-0.9 the optimum pilot interval can be calculated easily. Chamber Elect Engineers Bursa Branch, Istanbul Techn Univ, Fac Elect & Elect Engn, Uludag Univ, Dept Elect & Elect Engn, IEEE, Reg 8, IEEE Turkey Sect, CAS Chapter, Sci & Technol Res Council Turkey

This study aims to determine the signal strengths of three cellular system operators for 2G, 3G and 4G services on the basis of drive test measurements that were conducted twice on a specific route on Ondokuz Mayis University (OMU) Kurupelit Campus. Nine same brand and model smartphones with “Android” operating system and “Netmonitor” application were used during the synchronized measurements. Measurement results demonstrate that 2G signal strengths are significantly higher than 3G/4G, and the received signal strength can change depending on the location, frequency, line of sight, and base stations’ output power. Considering all operators and both of the measurement results; the signal strengths vary from -50dBm to -103dBm for 2G, while from -51dBm to -113dBm, and from -62dBm to -130dBm for 3G and 4G respectively. The average signal strengths of both measurements for 2G, 3G and 4G vary between -79.25dBm and -63.36, -87.22dBm and -74.51dBm, -105.88dBm and -88.36dBm. The second measurement results show that the quality of signal is lower than the minimum limit (

2012 IEEE 8th International Conference on Wireless and Mobile Computing, Networking and Communications, WiMob 2012 -- 8 October 2012 through 10 October 2012 -- Barcelona -- 94818 In this study, the effect of pilot arrangement on OFDM system performance for different time and frequency selective fading channels is investigated. Pilot symbols are placed in rectangular 2-D pilot pattern in chosen intervals both in time and frequency domain, and corresponding system performances are given in terms of BER. The pilot symbols that give the lowest BER for different channel profiles are determined as the optimum pilot symbols, and the interval between these optimum pilot symbols are defined as the optimum pilot interval in time and frequency direction. Then the relationships between the optimum pilot intervals and channels' coherence times and coherence bandwidths are evaluated. It is seen from the results the optimum pilot interval can be related best with coherence time and coherence bandwidth at 0.9 correlation. Therefore 2.5 pilot symbols per Bc,0.9 and 25 pilot symbols per Tc,0.9 can be used. © 2012 IEEE.

International Symposium on INnovations in Intelligent SysTems and Applications, INISTA 2012 -- 2 July 2012 through 4 July 2012 -- Trabzon -- 92831 In this study, the effect of three different techniques that used for interpolation on OFDM system with pilot based comb type channel estimation is investigated and results are given in terms of BER (Bit Error Rate). The estimation of channel at pilot subcarriers is done by LS (Least Square), and interpolation of channel at data subcarriers are obtained by low pass (LP) interpolation algorithm, ANFIS (Adaptive Network Based Fuzzy Inference Systems) and GRNN (Generalized Regression Neural Networks) artificial neural network (ANN) structures. The results show that there is a relationship between the number of used pilot bits and interpolation technique's performance. If the aim is to get high bandwidth efficiency over a given bandwidth LP algorithm should be used for interpolation, to get the lowest BER ANFIS or GRNN can be used. © 2012 IEEE.

In this study, the effect of pilot bit placement on the performance of an OFDM system with comb-type based channel estimator was investigated. Computer simulations were used for this purpose. Least sequares algorithm is employed to estimate the channel at pilot sub-carriers and low-pass interpolation to estimate the channel at data subcarriers. The pilot ratio (ratio of data bits to pilot bits) that gave the lowest bit error rate was determined as the Optimum Pilot Ratio (OPR) and spacing between the pilot sub-carriers as (Δf) OPR . Then the relationship between (Δf) OPR and channels' coherence bandwidths was investigated using four channels with different frequency selectivity. Simulation results show that, taking spectrum efficiency and channel estimation accuracy into account, two or three pilot subcarrier within coherence bandwidth at 0.9 correlation is likely to be an optimum choice.