Search

The shielding of radio wave by steel-containing structures is desirable for electronics protection but undesirable for telecommunication signal reception. This work investigates the shielding behavior of steel structures consisting of members in various configurations, with the practical aim of determining how the configuration can be exploited to control the shielding. Differently oriented continuous steel reinforcement (stranded/unstranded wires in the unidirectional, crossply and planar coil configurations) are evaluated for electromagnetic interference (EMI) shielding at 600-2000 MHz, using unpolarized radiation. The absorption loss SE (A) dominates the reflection loss SE (R). The crossply configuration gives the highest SE (A), SE (A)/thickness and SE (A)/SE (T) (SE (T) = total loss); the planar coil configuration gives the lowest values. The SE (A), SE (A)/thickness and SE (A)/SE (T) are moderately higher for the crossply configuration than the unidirectional configuration, because steel's electrical isotropy allows the 0 degrees electric field to interact with the 90 degrees wire. The SE (A)/SE (T) is comparable for the stranded and unstranded wires.

The aim of this work is to analyze the effect of tuning screws located at the cross iris of a dual-mode vacuum filled cylindrical waveguide filter. Dual-mode waveguide filters with and without cross iris screws are designed and manufactured. Their simulation and measurement results are compared. It is clear that the bandwidth of the filter (and also Finite Transmission Zero (FTZ) locations) can be adjusted with cross iris screws. So, design and mechanical production tolerances can be easily compensated depending on the technical requirements.

Placing dielectric lens structures into an antenna's aperture has proven to be one of the most reliable methods of enhancing its gain. However, the selected material and the prototyping method usually limit their fabrication process. With the advances in 3D printing technology and their applications, the microwave designs that were either impractical or impossible in the past to manufacture using traditional methods, are now feasible. Herein, a novel prototyping method by using 3D-printer technology for low-cost, broadband, and high gain dielectric lens designs has been presented. Firstly, the elliptical lens design has been modeled in the 3D EM simulation environment. Then fused deposition modeling based 3D-printing method has been used for the fabrication of the dielectric lens. The measured results of the 3D printed antenna show that the lens antenna has a realized gain of 17 to 20.5 dBi over 8-12 GHz. Moreover, the comparison of the prototyped antenna with its counterpart dielectric lens antenna in the literature has indicated that the proposed method is more efficient, more beneficial, and has a lower cost.

Interaction between water and lubrication grease oil is not desirable, but it is not inevitable. The operational life of the machine component is influenced by humid grease oil. Metameterial-based transmission line sensor application is proposed and its operation is validated both numerically and experimentally by inserting grease oil samples in the sample holder. The proposed sensor structure is able to determine the humidity ratio of grease oil samples. The proposed structure shifts resonance frequency to react to the grease oil's dielectric constant. The frequency shift of grease oil samples is monitored as about 300 MHz's. Linearity characteristic between resonant frequency and dielectric constant value is validated. The novelty of this article is that no such study has been conducted by employing non-destructive methods which provide long-term stability of the sensor structure.

This article presents a Ku-band Low Noise Amplifier (LNA) Monolithic Microwave Integrated Circuit (MMIC) and RF front-end module for space applications. LNA MMIC was developed with utilizing 0.07 mu m GaAs m-HEMT process. Noise Figure (NF) and gain results of LNA module were measured as 1.3 and 43 dB, respectively and OIP3 was measured as +20 dBm at the ambient temperature. The LNA module was tested in the temperature range between -25 degrees C and 75 degrees C and small signal gain and NF variation were less than 3 and 0.8 dB, respectively. This article describes the MMIC LNA design, mechanical chassis design, WR75 waveguide-to-microstrip design, and measurement results of the LNA front-end module.

WOS: 000526412600010, This study proposes a distributed cluster-based routing algorithm, distributed clustering with decreased uncovered nodes (DiCDU), alleviating the uncovered node problem occurring after the election of cluster heads. For the purpose of increasing the performance of the system in terms of the lifetime of the network, an energy-based cluster head election without requiring any extra control message is used. Moreover, an energy saving mode is proposed, in which the nodes perform static clustering controlled by predefined thresholds to conserve batteries. Extensive simulations are conducted for different values of cluster radius and the number of nodes and proposed schema is compared with similar methods, including a time-based cluster-head selection algorithm for low-energy adaptive clustering hierarchy, a clustering algorithm based on time delay, and regional energy aware clustering with the isolated nodes, for the death of the first, the half and the last nodes with the number of uncovered nodes. The results show that DiCDU outperforms compared approaches for all values of cluster radius and the number of nodes.

WOS: 000519806700073, In this study, composites composed of glass fiber reinforced-epoxy laminates interleaved with electrospun polyvinylchloride (PVC) nano-fibres were designed for radar absorption investigations. The laminated composites which were produced in special molds were obtained by placing woven glass fibers between each of PVC nanofiber mats, and the composites were produced in three different forms as pure, multi-walled carbon nanotubes doped and graphene doped. The morphologies of the PVC nanofiber mats were analyzed by scanning electron microscope. The radar absorption efficiencies of the composites in the individual and different combinations were measured in the 3-8 GHz frequency band. Experimental results show that the produced graphene-added composite material has improvable microwave absorption effect at several points in 3-8 GHz band to provide excellent absorption in future studies. The graphene doped structure was found to have a certain absorption characteristic up to 33.82% at a constant frequency. Besides, various strong absorption frequency points have been obtained in the related frequency range. The cascaded graphene doped composite layers can provide broadband absorption for stealth technology.

WOS: 000491513500001, In Power Line Communication, variations in the characteristics of power lines and additive noise reduce the efficiency of Orthogonal Frequency Division Multiplexing (OFDM), and that makes channel estimation essential. The earlier estimation techniques in the literature assume channel noise is Gaussian as in the wireless communication, whereas the recent ones model the corrupted noise more realistic, impulsive, which results in complicated receivers. This study judges the need of impulsive noise modelling and complex receivers. The performances of two Maximum A-Posteriori (MAP) channel estimators proposed for additive Gaussian noise and impulsive noise are compared under impulsive noise. The channel data used in the simulations is taken from the literature and impulsive noise is modelled by Middleton Class A distribution. The results show that the MAP estimator, which assumes Gaussian noise instead of impulsive, has better performance. The MAP estimator which assumes impulsive noise has a satisfactory performance under weak impulsive noise and low Signal to Noise Ratio (SNR) only, otherwise its performance is low, close to Maximum Likelihood estimator performance. The estimator designed for Gaussian noise has a better performance even under heavy impulsive noise and this distinction is clearer for low SNR cases.

This paper presents a system based on artificial neural network (ANN) that predicts ground plane design for desired radiation properties of a monopole antenna with operation band of 4.8 to 5 GHz. The operating frequency can be adapted to any other frequency regimes. Initially, a 180 x 180 mm2 ground plane, which is composed of a copper layer, is designed and integrated to a radiative pole that creates monopole antenna configuration. The ground plane is divided into 18 rows and 18 columns as 18 x 18 matrix so that each unit cell has a square shape having 10 mm side length. Moreover, 152 different ground plane configurations are created by using logic 1 s and 0 s. Multi-layered feed forward ANN is used along with Scale Conjugate Gradient learning algorithm to design ground plane of the monopole antenna. Simulated 152 random ground plane arrays and obtained radiation patterns are used to train ANN for the ground plane design. If a user wants to manipulate radiation, artificial neural network gives the optimum ground plane design for the desired radiation direction and gain with 91.03% accuracy. Finally, one test antenna is fabricated and experimentally measured to support the results of the simulated one. The proposed ANN model approach can be easily used for antenna applications in the antenna industry.

The expanding share of renewable energy sources (RESs) in power generation and rise of electric vehicles (EVs) in transportation industry have increased the significance of energy storage systems (ESSs). Battery is considered as the most suitable energy storage technology for such systems due to its reliability, compact size and fast response. Power converters are vital for the integration of batteries into power grid and EVs as they play an active role in both power conversion and battery management. Multilevel converters (MLCs) are types of power converters and attract widespread interest due to their improved power quality, reliability and modularity. There are two main challenges in MLC based battery storage systems (BSSs) which are selecting a proper MLC topology and balancing state-of-charges (SOCs) of batteries. Although some research has been carried out on either MLCs or SOC balancing, no single study exists which presents a comprehensive review on MLC based BSSs for large-scale grid and EV applications. This paper begins by reviewing several major battery storage technologies that are utilised in MLC based BSSs. Later on, a systematical review of commonly used and recently proposed MLC topologies for BSSs are provided along with different control schemes for MLCs by specifically focusing on SOC balancing techniques. Finally, potential challenges and suggestions for future improvement of MLC based BSSs are addressed.

Fast replacement models (or surrogates) have been widely applied in the recent years to accelerate simulation-driven design procedures in microwave engineering. The fundamental reason is a considerable-and often prohibitive-CPU cost of massive full-wave electromagnetic (EM) analyses related to solving common tasks such as parametric optimization or uncertainty quantification. The most popular class of surrogates are data-driven models, which are fast to evaluate, versatile, and easy to handle. Notwithstanding, the curse of dimensionality as well as the utility demands (e.g., so that the model covers sufficiently broad ranges of the system operating conditions), limit the applicability of conventional methods. A performance-driven modeling paradigm allows for mitigating these issue by focusing the surrogate setup process in a constrained domain encapsulating designs being of high quality w.r.t. the assumed figures of interest. The nested kriging framework capitalizing on this idea, renders the constrained surrogate using kriging interpolation, and has been shown to surpass traditional approaches. In pursuit of further accuracy improvements, this work incorporates the performance-driven concept into the fully-connected regression model (FRCM). The latter has been recently introduced in the context of frequency selective surfaces, and combined deep neural networks with Bayesian optimization, the latter employed to determine the network architecture and hyper-parameters. Using two examples of miniaturized microstrip couplers, our methodology is demonstrated to outperform both conventional modeling techniques and nested kriging, with reliable models constructed over multi-dimensional parameters spaces using just a few hundreds of samples. Icelandic Centre for Research (RANNIS) [206606051]; National Science Centre of PolandNational Science Centre, Poland [2020/37/B/ST7/01448] This work was supported in part by the Icelandic Centre for Research (RANNIS) under Grant 206606051, and in part by the National Science Centre of Poland under Grant 2020/37/B/ST7/01448.

A specially designed metallic E-shaped fractal-based perfect metamaterial absorber (PMA) with fairly wideband absorptivity in the K- and Ka-bands of the microwave regime was investigated. The PMA top surface is comprised of square-shaped split-ring resonators (SRRs) surrounded with the stated fractal design. The absorptivity of PMA was analyzed in the range of 20 - 30 GHz for the normal and oblique incidence of waves. Both the transverse electric (TE) and transverse magnetic (TM) modes were taken up to observe the robustness of the proposed design. It was observed that the fractal resonators exhibit capacitive effect at low frequencies, whereas the SRRs manifest capacitive effect at higher frequencies. The simulation and measured results were found to be in fairly good agreement. It is expected that the proposed design of PMA would be useful for 5G communication applications.

In this work, gain of a traditional horn antenna is enhanced up to 2.9 dB over X-band using 3D printed square-shaped multi-layer lens. For this purpose, firstly the multi-layer lenses are designed using Invasive Weed Optimization (IWO) and simulated in 3-D CST Microwave Studio (MWS) environment as consisting of square-shaped five layers with variable dielectric constants and heights. Thus, optimum values of the dielectric constants and heights are resulted limiting from 1.15 to 2.1 and 9.2 mm to 10 mm, respectively compatible for Fused Deposition Modeling (FDM) based 3D-printing process. Finally, the optimum lens is realized by 3D printer via FDM evaluating infill rate of cheap Polylactic Acid (PLA) material for each layer. The simulated and measured performance of the multi-layer dielectric structures are hand to hand. The horn antenna equipped by our proposed dielectric lens achieves gain enhancement of the traditional antenna up to 2.9 dB over the operation band. Furthermore, the proposed design is compared with the counterpart designs in literature and based on the comparison results it can be said that the proposed design achieves the better performance in the smaller in size as equipped a traditional X-band horn antenna. © 2021 Applied Computational Electromagnetics Society (ACES). All rights reserved.

WOS: 000485689600006, This paper deals with the computation of all proportional-integral (PI)-based pitch controllers which achieve the desired frequency-domain specifications, namely, gain and phase margins (GPMs) of a large wind turbine (LWT) with communication delays. An efficient graphical method based on extracting the boundaries of stability regions in PI controller parameter space having user-defined GPMs has been employed to determine GPM-based stability regions for a wide range of time delays. The theoretical region boundaries are validated by using a powerful numerical method known as the quasi-polynomial mapping-based root finder (QPmR) and time-domain simulations. Results indicate that the proposed scheme gives an improved dynamic response compared to the recently developed scheme based on stability only for the pitch control of LWTs with communication delays.

This paper presents a new reflection-only set-up for characterizing the properties of an anisotropic PEC-backed materials. Albeit, the reflection-only methods are established long ago, they are not elaborated appropriately for retrieving industrial anisotropic materials. In spite of other researches, this method is capable to determine tensors of both permittivity and permeability of an anisotropic PEC-backed material. In contrast to similar researches, this method is mathematically simple and easy to implement. Tensors of epsilon and mu of PEC-backed sample are characterized by rotating sample and measuring reflection coefficient in various configuration. Not measuring the transmission, in order to provide enough equations, the higher order mode of the waveguide is employed. A three-port probe is designed for this goal and optimized to excite the TE(10)and TE(20)modes simultaneously. Good agreement of retrieved parameters from experimental measurements with those of actual ones shows the reliability of this set-up for characterization of PEC-backed anisotropic composites.

WOS: 000531764100019, In this paper, a new design of microstrip power limiter which is based on microstrip technology and zero bias Schottky diode is introduced. In this context, the FR-4 substrate that was characterized by dielectric permittivity (4.4), dielectric thickness (1.6 mm), and the HSMS 286k Schottky diode is used to design the proposed power limiter. The planar resonators are designed, optimized, and simulated with the shunting of the HSMS 286k diodes by using Schematic solver integrated in ADS from Agilent Technologies. The simulation results are significant in terms of high impedance matching, strong insertion of the low power, and good limitation ratio of the high power. The proposed power limiter is fabricated and tested in the measurement part. It is observed that the results are in agreement with the numerical analysis in terms of matching, isolation, and power limitation. The achieved microwave power limiter offers simple construction, small size (44 x 40 mm(2)), wide bandwidth, and good limitation ratio less than 10 dBm when the input power reaches 30 dBm.

Salt and pepper (SAP) noise elimination is a crucial step for further image processing and pattern recognition applications. The main aim of this article is to propose a novel SAP noise elimination method which employs a regression-based neuro-fuzzy network for highly corrupted gray scale and color images. In the proposed method, multiple neuro-fuzzy filters trained with artificial bee colony algorithm is combined with a decision tree algorithm. The performance of the proposed filter is compared with a number of well known methods with respect to popular metrics including, structural similarity index, peak signal-to-noise ratio, and correlation on well known test images. The results reveal that the proposed filter has superior performance in terms of all comparison metrics.

7th Global Conference on Global Warming, GCGW 2018 -- 24 June 2019 through 28 June 2019 -- 233979, Solar-powered systems can supply clean and sustainable energy for both service requirements and also for the propulsion of marine vessels. However, the restricted available area for photovoltaic panels and high setup costs inhibits the sufficient energy production for satisfying the whole needs of vessels. Due to the limited panel area that can be installed on the vessel, it is necessary to improve the system efficiency in order to obtain more power from the existing solar panel system. In this study, cooling solar panels from the back surface with seawater in an open loop cooling water circuit for a 527-W solar-powered system are investigated. In order to observe the effects of cooling the panels, thermodynamic modeling and analysis of a foldable photovoltaic panel set have been carried out. The result illustrates the potential of these systems as the power output difference of the panel set is more than the consumed power for cooling on above-specific irradiation conditions. The remaining power output, which would be up to 37% of the uncooled system, is high enough to be utilized to speed up the marine vessels or to increase their range. © Springer Nature Switzerland AG 2020.

In this paper, we consider the problem of joint user scheduling and dynamic pilot allocation in a Time-Division Duplex (TDD) based Massive MIMO network under varying traffic condition. One of the main problems with Massive MIMO systems is that the number of available orthogonal pilot signals is limited, and the dynamic allocation of these signals to different users is crucially needed to utilize the full benefit of these systems. In addition, pilot signals are radio resource control (RRC) configured in practice, and hence the frequent reconfiguration causes high signaling overhead and is costly. Using Lyapunov optimization framework, we develop an optimal algorithm that first assigns pilots dynamically based on queue sizes and the channel conditions of users as well as the reconfiguration cost at large time-scale. Then, it schedules users on a small-time scale. Numerical results show the efficacy of our algorithm and demonstrate that pilots do not need to be configured frequently at the expense of increased queue delay., Comment: submitted

Chronic obstructive pulmonary disease (COPD) is one of the deadliest diseases which cannot be treated but can be kept under control in certain stages. COPD has five severities, including at-risk, mild, moderate, severe, and very severe stages. Diagnosis of COPD at early stages needs additional clinical tests for even experienced specialists. The study aims at detecting the severity of the COPD to start treatment for preventing the progression of the disease to the next levels. We analyzed 12-channel lung sounds with different COPD severities from RespiratoryDatabase@TR. The lung sounds were recorded from the clinical auscultation points from 41 patients on posterior (chest) and anterior (back) sides. 3D second-order difference plot was applied to extract characteristic abnormalities on lung sounds. Cuboid and octant-based quantizations were utilized to extract characteristic abnormalities on chaos plot. Deep extreme learning machines classifier (deep ELM), which is one of the most stable and fast deep learning algorithms, was utilized in the classification stage. Novel HessELM and LuELM autoencoder kernels were adapted to deep ELM and reached higher generalization capabilities with a faster training speed against the conventional ELM autoencoder. The proposed deep ELM model with LuELM autoecoder has separated five COPD severities with classification performance rates of 94.31%, 94.28%, 98.76%, and 0.9659 for overall accuracy, weighted-sensitivity, weighted-specificity, and area under the curve (AUC) value, respectively. The proposed deep analysis of 12-channel lung sounds provides a standardized and entire lung assessment for identification of COPD severity. Our study is a pioneering approach that directly focuses on lung sounds. Novel deep ELM kernels have performed a higher generalization and fast training compared to conventional kernels.

WOS: 000427715600070, In this work we present physical, electrical and magnetic properties of beta-Fe1.1Se single crystalline alloys produced by chemical vapor transport technique using short (120 h) and long (700 h) heating processes. The best T (c) was obtained from the long time processed samples. Magnetization results showed that samples are typical type-II superconductor. Calculated critical current density values, at zero field, were found to be 1.1 x 10(6) Acm(-2) for long time processed samples at 2 K and indicates strong pinning mechanism and bulk superconducting nature. The zero temperature value of higher upper critical field was calculated to be H (c2)(0) = 244 kOe. Calculated values of coherence length were found between 3.65 and 3.67 nm. Pauli paramagnetic limit, H (P) (0) = 1.84T (c) , is exceeded for both series of samples. Results obtained suggested that the spin-paramagnetic effect possibly the dominant pair-breaking mechanism for both series of samples., Scientific and Technological Research Council of Turkey, TUBITAK [115F278], This work was supported by the Scientific and Technological Research Council of Turkey, TUBITAK (Project Grant No. 115F278).

WOS: 000431278700016, By using a metasurface (MS) structure, a linearly polarized wave is converted to circularly polarized waves. Both right- and left-handed circular polarizations (RHCPs and LHCP) are obtained by a simple configuration in the proposed structure which consists of 16 unit cells arranged in a 4 X 4 layout. Each unit cell contains five horizontal and parallel strips embedded in a rectangular frame in which a single diagonal strip is placed from one corner to the opposed one. It is shown that the orientation of the diagonal line determines the handedness of the converted signal to be either LHCP or RHCP. In order to show the working conditions of the MS structure, scattering parameters are found for both co-polarized and cross-polarized responses. Axial ratio, an indicator for polarization conversion, is then obtained by dividing cross-polar response to co-polar response to demonstrate the transformation. The structure works for horizontally and vertically polarized linear waves in a wide band frequency range which is approximately 510 MHz. Since the suggested MS model is composed of a simple geometry for polarization conversion, it can be easily adjusted in any desired frequency bands for a variety of applications from the defence industry to medical, education, or communication areas.

WOS: 000404530900034, A metamaterial-based sensor has been realized to distinguish authentic and inauthentic fuel samples in the microwave frequency regime. Unlike the many studies in literature on metamaterial-based sensor applications, this study focuses on a compact metamaterial-based sensor operating in the X-band frequency range. Firstly, electromagnetic properties of authentic and inauthentic fuel samples were obtained experimentally in a laboratory environment. Secondly, these experimental results were used to design and create a highly efficient metamaterial-based sensor with easy fabrication characteristics and simple design structure. The experimental results for the sensor were in good agreement with the numerical ones. The proposed sensor offers a more efficient design and can be used to detect fuel and multiple other liquids in various application fields from medical to military areas in several frequency regimes., TUBITAK [115E788]; Turkish Academy of Sciences, F.D. acknowledges support from TUBITAK under Project No. 115E788 and partial support from the Turkish Academy of Sciences.

This paper presents the moving target focusing method, which allows focusing moving targets in complex synthetic aperture radar (SAR) images without raw data. The method is developed on the range migration algorithm, where focusing moving target is an interpolation step in the wave domain. The simulated results are provided in the paper to illustrate the proposed method whereas the experimental results show its practicality. The method can be flexibly applied from small area to the whole SAR scene.

4th International Conference on Power Electronics and their Applications (ICPEA) -- SEP 25-27, 2019 -- Elazig, TURKEY, WOS: 000523476700030, In this paper, the design and analysis of a single phase grid-connected fuel cell system is presented. For this, proton exchange membrane fuel cell (PEMFC) is used as an energy generation unit and the system is integrated into the utility-grids/loads through a single phase inverter. For this purpose, all/dq conversion based power flow controller is employed in single phase H-bridge inverter. The system is constructed through Matlab/Simulink environment program. In the performance/analysis section, the system is tested for different load conditions. The power flow waveforms and system voltages/currents are given in modeling results. In case studies, it is obvious that the excess power is supplied to the grids and the lacking power is provided from the grids to feed loads., Ziane Achour Univ Djelfa, Firat Univ, Djelfa Univ, Fac Sci & Technol, Appl Automat & Ind Diagnost Lab, IEEE Algerian Sect, IEEE Turkey Sect, IEEE Power Elect Soc, IEEE Power & Energy Soc, IEEE Ind Applicat Soc, Djelfa Univ, IEEE, Firat Univ, Engn Fac

4th International Conference on Power Electronics and their Applications (ICPEA) -- SEP 25-27, 2019 -- Elazig, TURKEY, WOS: 000523476700044, In this paper, a transformer-less grid-connected PV system using low voltage panels is designed and analyzed for residential applications. For this, dual-level dc-dc boost converter is used to obtain a higher voltage level at the output, and the system is integrated into the utility-grids/loads through a three-phase inverter. By this way, the designed system reduces the cost and dimension in comparison with a conventional system. In the designed system, the switching operation of dual-level dc-dc converter is achieved using perturb & observe maximum power point tracking method. In the performance/analysis section, the system is tested for different load groups and irradiation levels. The results show that the system increases the PV voltage to the desired voltage value. Also, the system is analyzed for three irradiation levels and two local load groups. In case studies, it is obvious that the excess power is supplied to the grids and the lacking power is provided from the grids to feed loads., Ziane Achour Univ Djelfa, Firat Univ, Djelfa Univ, Fac Sci & Technol, Appl Automat & Ind Diagnost Lab, IEEE Algerian Sect, IEEE Turkey Sect, IEEE Power Elect Soc, IEEE Power & Energy Soc, IEEE Ind Applicat Soc, Djelfa Univ, IEEE, Firat Univ, Engn Fac

6th International Conference on Electrical and Electronics Engineering (ICEEE) -- APR 16-17, 2019 -- Istanbul, TURKEY, WOS: 000494805700014, Recently, sliding mode control because of convenience and robustness has become a preferred method. In this paper, LMI-based sliding mode controller is designed for speed control of Precision Modular Servo experiment (PMS). For ensure the stability of the system the Lyapunov stability theorem is used. The experimental results is used to affirm that the proposed controller ensures suitable tracking performance and chattering reduction., Cukurova University Scientific Research Projects UnitCukurova University [FDK-2018-10464], This work has been supported by the Cukurova University Scientific Research Projects Unit under Grant No. FDK-2018-10464.

WOS: 000460453100090, A micro sensor based on a V-shaped resonator (VSR) is implemented for the purpose of determining fiber content and ratio in construction materials as a nondestructive method. Concrete is investigated as the construction material in the study. First, electrical properties of concretes reinforced by different fiber types and ratios are investigated using the Nicolson-Ross-Weir technique. These values are used to design a nondestructive sensor based on microwave transmission line methods. At the resonance frequency, the VSR has a dense electric field. Construction material which is positioned within range of the VSR can change the distribution of the electric field, thus affecting the resonance response and transmission magnitude in the operating frequency. Since construction materials having various contents have different complex dielectric permittivity and loss tangent values, the resonance frequency, transmission magnitude and bandwidth of VSR shift correspondingly. Alterations in the resonance frequency and magnitude of transmission values which are related to the permittivity of the construction materials enable us to detect characteristics of the content in construction materials. The proposed technique is not only capable of sensing the type of content in the construction material which is positioned within range of the VSR, but it is also capable of determining the percentage of this content. Results show that the proposed microwave-based VSR sensor provides a cost-efficient and nondestructive solution for sensing the type and percentage of the contents in fiber-reinforced concretes.

WOS: 000490998600002, A dynamic voltage compensator (DVC) technique is presented for the minimizing of the capacitance value of the interleaved power factor corrected (PFC) boost converter for the battery charger in electric vehicles. This technique is based on eliminating the ripple on the capacitor by creating a voltage in the opposite direction as well as the amount of ripple on the capacitor. With the proposed method, the capacitance value is reduced by approximately five times. Reducing the size of the capacitor also provides the use of film-capacitors with a longer life. The other contribution of this study is designing a faster and more stable fully-digital control system, instead of the commonly used analogue controller of interleaved PFC boost converter. A 3.3 kW interleaved PFC boost converter is designed to verify the effect of the designed dynamic voltage compensator and digital controller., Scientific Research Project Unit of Cukurova UniversityCukurova University [FDK-2018-11231], This research study is supported by the Scientific Research Project Unit of Cukurova University with the project number of FDK-2018-11231.

Data classification is the process of organizing data by relevant categories. In this way, the data can be understood and used more efficiently by scientists. Numerous studies have been proposed in the literature for the problem of data classification. However, with recently introduced metaheuristics, it has continued to be riveting to revisit this classical problem and investigate the efficiency of new techniques. Teaching-learning-based optimization (TLBO) is a recent metaheuristic that has been reported to be very effective for combinatorial optimization problems. In this study, we propose a novel hybrid TLBO algorithm with extreme learning machines (ELM) for the solution of data classification problems. The proposed algorithm (TLBO-ELM) is tested on a set of UCI benchmark datasets. The performance of TLBO-ELM is observed to be competitive for both binary and multiclass data classification problems compared with state-of-the-art algorithms.

4th International Conference on Power Electronics and their Applications (ICPEA) -- SEP 25-27, 2019 -- Elazig, TURKEY, WOS: 000523476700011, In this paper, dynamic operation and optimization of a grid connected hybrid system including photovoltaics (PV) and fuel cell (FC) is presented. For this purpose, abc/dq transform based power flow controller is used in inverter-part in order to achieve the optimal power flow from energy generation sources to utility-grid. Also, a maximum power point tracking algorithm is implemented to control dc-dc conversion part in the hybrid system which is tested under variable conditions such as different system temperatures for FC stack and different irradiation levels for PV module. The system is designed for a three phase grid connection at no-load conditions. The proposed system is designed and tested through Matlab/Simulink environment. The performance results are obtained for three case studies. The performance results show that the designed system have excellent results under different operating conditions., Ziane Achour Univ Djelfa, Firat Univ, Djelfa Univ, Fac Sci & Technol, Appl Automat & Ind Diagnost Lab, IEEE Algerian Sect, IEEE Turkey Sect, IEEE Power Elect Soc, IEEE Power & Energy Soc, IEEE Ind Applicat Soc, Djelfa Univ, IEEE, Firat Univ, Engn Fac

4th International Conference on Power Electronics and their Applications (ICPEA) -- SEP 25-27, 2019 -- Elazig, TURKEY, WOS: 000523476700020, The RDI (Reduction Degradation Index) is an important quality criterion of sinter. In this study, a fuzzy logic based model has been developed to obtain the desired RDI value continuously. The expected RDI value for stable production in ISDEMIR (Iskenderun Iron and Steel Co.) blast furnaces is 30% -35% for -3.15 mm The aim of the study is to make the necessary interventions to ensure the desired RDI value automatically. The model developed in this study has five inputs and three outputs. With this model, coke, limestone and dunite ratios are adjusted automatically to achieve the desired RDI value. With this model successfully applied in Isdemir sinter plants, the human factor was eliminated., Ziane Achour Univ Djelfa, Firat Univ, Djelfa Univ, Fac Sci & Technol, Appl Automat & Ind Diagnost Lab, IEEE Algerian Sect, IEEE Turkey Sect, IEEE Power Elect Soc, IEEE Power & Energy Soc, IEEE Ind Applicat Soc, Djelfa Univ, IEEE, Firat Univ, Engn Fac

WOS: 000482043000001, Electromagnetic band gap (EBG) integrated monopole antenna is investigated in deformed cavity resonator in this study. The operation frequency is chosen as X band frequency regime and designs are completed for this frequency. Firstly, a square grounded monopole antenna is designed and analytically examined, then EBG grounded monopole is designed and tested. After that operation, an 8 cm x 8 cm x 8 cm cubic cavity resonator designed and antennas are examined in it. Moreover, a cuboid deformation is added in one corner of metallic cavity resonator to perturb rectangular eigenmodes. Also, tunability of this structure is tested by various resistive lumped elements, and according to results, resonance shifting and magnitude changes are obtained. This suggested structure is also an adjustable impedance surface and can be used in sensing, detection and microwave imaging applications.

4th International Conference on Power Electronics and their Applications (ICPEA) -- SEP 25-27, 2019 -- Elazig, TURKEY, WOS: 000523476700003, This study focused on fuel cell electric unmanned aerial vehicle (FC-EUAV) in order to find solutions to problems such as the short-lived and limited long flight endurance of unmanned aerial vehicles operating with fossil fuels harmful to the environment and battery-powered unmanned aerial vehicles. Polymer electrolyte membrane fuel cell, Li-ion battery, and supercapacitor triple hybrid power system provides power to FC-EUAV system. DC/DC converters are used to fix the variable output currents and voltages of these technologies. An electronic control unit is employed to manage the energy flow of the system with an appropriate control strategy. System performance has been analyzed in various flight scenarios. The results show how efficient the FC-EUAV system is for long endurance flights and different payloads., Ziane Achour Univ Djelfa, Firat Univ, Djelfa Univ, Fac Sci & Technol, Appl Automat & Ind Diagnost Lab, IEEE Algerian Sect, IEEE Turkey Sect, IEEE Power Elect Soc, IEEE Power & Energy Soc, IEEE Ind Applicat Soc, Djelfa Univ, IEEE, Firat Univ, Engn Fac

During the classification of streaming data, changes in the underlying distribution make formerly learned models insecure and imprecise, which is known as the concept drift phenomenon. Online learning derives information from a vast volume of stream data, which are usually affected by these changes in unforeseen ways and are currently generated primarily by the Internet of Things, social media applications, and the stock market. There is abundant literature focused on addressing concept drift using detectors, which essentially attempt to forecast the position of the change to improve the overall accuracy by altering the base learner. This paper presents novel hybrid pairs (classifier and detector) collected from a large-scale comparison of 15 drift detectors; drift detection method (DDM), early drift detection method (EDDM), EWMA for concept drift detection (ECDD), adaptive sliding window (ADWIN), geometrical moving average (GMA), drift detection methods based on Hoeffding’s bound (HDDMA and HDDMW), Fisher exact test drift detector (FTDD), fast Hoeffding drift detection method (FHDDM), Page–Hinkley test (PH), reactive drift detection method (RDDM), SEED, statistical test of equal proportions (STEPD), SeqDrift2, and Wilcoxon rank-sum test drift detector (WSTD) and six classifiers; Naive Bayes (NB), Hoeffding tree (HT), Hoeffding option tree (HOT), Perceptron (P), decision stump (DS), and k-nearest neighbour (KNN), to determine and recommend the best pair in accordance with the properties of the dataset. The objective of this study is to assess the contribution of a detector to a classifier and obtain the most efficient matched pairs. Through these pairwise comparison experiments, the accuracy rates and evaluation times of the pairs, as well as their false positives, true negatives, false negatives, true positives, drift detection delay, and the MCC. Additionally, the Nemenyi test is employed to compare the pairs against other methods to identify the method(s) for which there is a statistical difference. The results of the experiments indicate that the most efficient pairs—which differed for each dataset type and size—primarily include the HDDMA, RDDM, WSTD, and FHDDM detectors.

WOS: 000386367000125, Operation frequencies of traditional metamaterial absorbers are fixed meaning that it is not possible to change that frequency after the fabrication. Therefore, more studies are focused on the design of Tunable metamaterial absorber (TMA) since it is important to expand operation frequency. If the impedance of one or more layers of an absorber can be changed according to the applied electrical optical signal, then it would be possible to realize tunable absorbing designs. However, TMA studies reported previously are mainly focused on absorbing mechanism at microwave frequencies. In this study, TMA with varactor diode is designed and analyzed for absorber and sensor configurations. TMA is constructed by using a simple rectangular-shape geometry having two splits and a varactor diode placed at the right split. Numerical and experimental results show that perfect absorption is achieved when 0-10 V reverse bias voltage is applied. Resonance frequency can be easily tuned by changing the reverse bias voltage. Frequency dependent absorption behavior of TMA is presented with respect to different incident angles for TE and TM polarizations. A sensor application, knowing the absorption resonance frequency can provide the ability to determine the temperature of materials. The novelty of the study is to determine the temperature or the other parameters such as humidity or pressure by using TMA. It is also possible to determine the material type or its density if limited resource such as frequency generator is present.

WOS: 000371012400009, In this study, the frequency selective surface (FSS), absorbance and sensing applications of new unit cells comprised of single, double and quad U-shaped metallic elements are numerically and experimentally investigated. The numerical results are realised by using finite integration technique-based electromagnetic simulation software, CST Microwave Studio. Experimental results are obtained by means of Agilent N5234A PNA-L vector network analyser. The simulated and measured results of U-shaped FSSs are carried out by using two different ways; periodic unit cell and waveguide boundary conditions. The single and quad U-shaped FSS elements show a single band-stop filter property, whereas the double U-shaped FSS shows a dual-frequency band-stop filter behaviour. Absorber and sensor applications of the proposed U-shaped FSSs are illustrated both numerically and experimentally. The three types of U-shaped FSS structures show a narrowband absorbance which has potential in biomedical and sensing applications. Single and dual absorber characteristics are observed with a 90% absorbance. For the sensor configuration, 800 MHz bandwidth is obtained for sensing different materials showing that it is possible to realise different microwave sensor studies in industries of food and agriculture. Simulated and measured results are compared for FSS, absorber and sensor configurations, and the results show a good agreement with each other., Kilis 7 Aralik University [2014/01/MAP/02], This work was financially supported by Kilis 7 Aralik University with the Project number 2014/01/MAP/02.

This paper presents a design approach of a filtering antenna arrays based on the coupling matrix theory. The approach generates filtering functionality using the resonating array radiating elements and the resonator based feed network regardless to the physical structure. To implement the approach, a novel topology for a two-element array is presented, here three rectangular waveguide cavity resonators have been employed to form the filtering array. The array has a fractional bandwidth of 10% at the centre frequency 10 GHz with a reflection coefficient magnitude within the passband of 20 dB. The realised gain over the passband is 9.8 ± 0.4 dBi. The array has been fabricated and the measurements are in very good agreement with the simulations, validating the approach. © 2020 Elsevier GmbH, Engineering and Physical Sciences Research Council: EP/M016269/1, The authors would like to thank the U.K. Engineering and Physical Science Research Council to support this work financially, Contract EP/M016269/1 .

The detection of branded and unbranded chemical materials is essential for the quality control assessment. In this work, a metamaterial inspired sensor is designed and fabricated, which incorporates oval-shaped wing resonators, in order to use to detect branded and unbranded diesels in the X-band frequency region. The simulation studies were carried out by using the Computer Simulation Technology (CST) Microwave studio. A transmission line was introduced into the sensor design and genetic algorithm was used to optimize the proposed structure. Parametric study was investigated by changing the permittivity, permeability of the sensor layer, width of the transmission line, materials of the substrate layer, and width of the resonator. Results showed that different factors can be considered to sense the chemical materials including the shift in resonant frequency and amplitude variation in the reflection or transmission spectrum. It was found that the sensible variation in the transmission value is about &minus, 3.2 dB, which is superior to that reported in literature. It was concluded that the sensor is highly sensitive to distinguish the branded diesel from the unbranded one, which makes it viable for detecting fluidics in the chemical industry and medicine.

3rd International Conference on Computer Science and Engineering, UBMK 2018 -- 20 September 2018 through 23 September 2018 -- -- 143560, This paper presents a new approach to utilize smart technology in a practical and meaningful manner to make finding seats easier for audiences in cinema halls. Generally, the audiences come to cinema halls late and they cannot find their exact seats easily, because there are many places to sit and many small signs (numbers, letters etc.) to define them. Especially, the low lighting of these halls makes seeing seat's number and/or letter much harder. Due to these reasons, smart cinema seat system has been designed by using lights inside the seats which can catch the attention of people. The system is based on an Arduino microcontroller board with a group of sensors and an Android application that can communicate with the microcontroller and server database of the cinema. The lights and sensors have been connected to Arduino microcontroller board and the board has been controlled with the Android application (App) via Bluetooth protocol. The proposed system is a novel idea for smart technology and the results showed it has worked successfully and helped people effectively in finding their seats. © 2018 IEEE.

12th International Congress on Artificial Materials for Novel Wave Phenomena, MetaMaterials 2018 -- 27 August 2018 through 1 September 2018 -- -- 142487, The possibility of negative refractive index in plasma and magnetic materials was considered with a new approach. It is shown that simplification of fundamental equations by neglecting losses leads to losing important features about refractive index and therefore, it is expedient to take into consideration imaginary parts of dielectric permittivity and magnetic permeability for an accurate statement of the problem. Also active materials were briefly discussed via new approach. © 2018 IEEE., FDK-2017-8948, The authors would like to acknowledge the Scientific and Technological Research Council of Turkey (TÜBİTAK) and the Scientific Project Unit of Cukurova University (FDK-2017-8948) for full financial support.

WOS: 000443021000068, A metamaterial-based permittivity and thickness sensor structure for dielectric substrate material has been proposed at the X band frequency regime. The sensor structure is designed by using a split meander line type resonator and examining it both numerically and experimentally. Various types of dielectric substrate samples have been used to verify the precise sensing characteristics of the proposed sensor. The sensor layer has been chosen as the back side of the sensor structure, and the reflection frequency of the incident signal has been examined The sensor layer thickness has been varied from 0.4 mm to 1.6 mm for the thickness sensing study with two different types of dielectric substrate having the same electromagnetic characteristics. The permittivity sensing study has been carried out by several dielectric materials which have permittivity values between 10.20 and 1.96. The proposed sensor structure can be effectively used in many application areas such as microwave material design, the defense industry and in medical devices., Scientific Project Unit of Cukurova University [FDK-2018-10488], The authors would like to acknowledge the Scientific Project Unit of Cukurova University (FDK-2018-10488).

WOS: 000431278700009, Metamaterial-based energy harvesting structures operating at GSM goo and GSM 1800 frequency bands have been proposed. The basic structure is composed of four nested U-shaped elements on the front and back side of the dielectric substrate, with a 180 degrees relationship between the front and back resonators. As energy harvesting capability is directly related to the quality of absorption, with the aim being perfect absorption, there is an air gap to allow tuning of the resonance frequency, and copper plate follows the air gap to facilitate the perfect absorption of electromagnetic waves, which is verified by means of simulation and experimental tests. A set of simulations and experimental study were further carried out to demonstrate incident and polarization angle dependency, the effects of Schottky diodes, and the optimal orientation of the U-shapes. Spectrum analysis and DC voltage measurements across the HSMS 2860 Schottky diode are also presented to test the energy harvesting capability: the spectrum analyzer shows a 40 dBm difference, while 81.7 mV maximum DC voltage is observed at 900 MHz. The simulation and experimental study results, while displaying several differences, do suggest that the proposed design can be used for running low-energy consumption devices such as sensors and switches.

WOS: 000427715600041, Synthesis and characterization of FeTe0.5Se0.5 single crystals prepared by self-flux technique with two different cooling rates of 1.45 and 5.83 a"integral/h have been investigated. The XRD results show that the samples have tetragonal structure. The SEM results indicate that the samples demonstrate a terrace-like formation. The superconducting transition temperatures of two samples obtained as magnetization measurement are seen to be 14.62 and 14.38 K for sample A (5.83 a"integral/h) and sample B (1.45 a"integral/h), respectively. The M-H curves reveal the existence of ferromagnetism in all measured temperatures. The normalized pinning force f(F-p/F-pmax) at h(H/H (irr) ) curves are scaled using the Dew-Hughes model given by f(h) = Ah (p) (1 - h) (q) with A = 2.73, p = 0.81 and q = 0.69, the ratio [p/p + q] ae 0.54 for cooling rate of 5.83 a"integral/h sample., Cukurova University [FDK-2017-8224, FBA-2015-4464], This work was supported by Research Fund of Cukurova University [Grant Nos.: FDK-2017-8224, FBA-2015-4464].

WOS: 000425716800005, A novel metamaterial absorber structure is designed and characterized for microwave energy harvesting. The suggested structure is composed of two circular ring resonators with different dimensions. Due to harvesting application of the proposed structure, the main operation frequency of the suggested structure lies in WIMAX and satellite communication frequency bands and surrounds our environment. The optimum dimensions of the suggested structure are obtained through parametric study by genetic algorithm in order to realize wideband absorption and harvesting response. Simulation results show that the metamaterial-harvester-based resistive loads are useful to absorb and convert microwave energy for the operation frequency. The simulated harvested power across the resistors has been found greater than 0.4 W, which corresponds to 80% efficiency between 7.8 and 14 GHz. In addition, polarization dependence and angular stability of the proposed harvester are investigated at operation frequency to support the simulation of an experimental study for S-parameter measurement. Therefore, simulation and experimental study results show that the proposed design with good absorption and harvesting characteristics can be operated in WIMAX and satellite communication frequency bands.

12th International Congress on Artificial Materials for Novel Wave Phenomena, Metamaterials 2018 -- 27 August 2018 through 1 September 2018 -- -- 142487, This manuscript focus on developing of new metamaterials sensor based on distinction of different material and purity ratio sample. Unique side of this study is having very clear and sensitive results and presenting new approach to the microfluidic sensor applications by using sample holder. The procedure of this study consist of three steps, measurement of dielectric constant by using Agilent 85070E dielectric measurement kit, developed of proper structure and simulation result, taking experimental output by using sensor layer. © 2018 IEEE., 117M855, Acknowledgement We would like to thank the Scientific and Technological Research Council of Turkey (117M855) for the financial support.