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https://hdl.handle.net/20.500.12451/264

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User-Centric Visible Light Communication
(IEEE, 2024) Horunlu, Kardelen; Çelik, Yasin
Visible light communication (VLC) takes its place among the 5th Generation (5G) and beyond wireless communication systems. In these systems that aim to achieve high data rates, the multiple-input multiple-output (MIMO) data transmission technique comes to the fore. Especially in indoor environments, the performance of the VLC system is seriously dependent on user location. One of the important reasons for this dependence is that the correlation between channels varies depending on location. In this paper, the achievable data rates of user-centric (UC) transmission techniques for MIMO VLC wireless communication systems using the angular diversity receiver (ADR) and generalized ADR (GADR) models are obtained. At any given location, the SD-aid adaptive SMP (SD-aSMP) technique has been shown to perform best. It is shown by the cumulative distribution function (CDF) graph that GADR provides higher data rates than ADR in terms of receiver structures.
Performance Analysis of Fractional-Order Controllers for Blade Pitch Angle Control of a Wind Turbine
(Institute of Electrical and Electronics Engineers Inc., 2024) Soylu, Selim
Designing an optimal blade pitch angle controller for a wind turbine (WT) presents a critical engineering challenge, affecting the turbine's reliability, safety, and power output efficiency. This research investigates the blade pitch angle controller design for a 500 kW WT using five different fractional-order controllers (FOCs) in a simulated environment. To optimize the parameters of these FOCs, a bio-inspired metaheuristic method known as the artificial hummingbird algorithm (AHA) is employed. A fitness function is determined based on the error between nominal output power and measured output power of the WT, and an optimization process is performed to minimize this fitness function. For reliability of the optimization process, 30 independent runs are performed, and their statistical data is recorded. Following the optimization process, the power output and time response characteristics of the WT system are evaluated by simulation studies to determine their performance. The simulation results indicate that the system controlled with the fractional-order proportional-derivative (FOPD) controller achieves the best transient response characteristics with a maximum overshoot of 1.104%, maximum undershoot of 2.491% and settling time of 0.037 seconds and outperforms the other four FOCs. ©
Approximation of higher order electric vehicle system incorporating factor Division method
(Institute of Electrical and Electronics Engineers Inc., 2023) Waghmare, A.V.; Meena, V.P.; Arslan, Emre; Yadav, U.K.; Singh, V.P.
In this paper, an approximation of linearized electric vehicle (EV) system is performed. A second-order approximated model is obtained for fifth-order linearized EV system. The approximation is performed to clarify and demonstrate the applicability and usefulness of the approximation method used in this paper. This paper aims to estimate a suitable approximated model of order two, for a linearized EV system, by utilizing the factor division method. Comparisons based on time domain specifications are provided to demonstrate the practicality of the model. Even after performing the approximation, it is found that the model obtained is stable and retains the properties of the original system. For proving efficacy and effectiveness of the suggested method, step response, Bode response, Nyquist response, and impulse response are also presented.
Performance Comparison of Metaheuristic Algorithms on FOPID-Controlled Anti-Cancer Drug Delivery System
(Institute of Electrical and Electronics Engineers Inc., 2023) Ay, Sena; Soylu, Selim
Chemotherapy is one of the most effective and preferred treatment methods in cancer treatment. It is essential to finely adjust chemotherapy drug doses for the patient's survival and comfort in terms of side effects during the treatment process. In this study, a well-known anti-cancer drug scheduling patient model was used. This patient model was controlled by an optimized fractional order proportional-integral-derivative (FOPID) controller. In the optimization process five different swarm-based metaheuristic algorithms such as AHA, GWO, PSO, SSA, and WOA were used. To compare their performances, each algorithm was run independently 30 times and statistical data was collected. As a result of the simulation studies, the GWO-based optimal FOPID (GWO-FOPID) and PSO-based optimal FOPID (PSO-FOPID) controllers outperformed with the final number of cancer cells (CCs) of 35.253 and 35.255, respectively. Moreover, the highest performance index of 24.07 was achieved for these controllers.
Effect of Pulse Shaping on the Performance of Spatial Modulation
(Istanbul Technical University, 2023) Gündem, Sümeyra; Aldırmaz-Çolak, Sultan; Çelik, Yasin
In this paper, the effect of pulse shaping in the spatial modulation (SM) method is investigated. In the SM, extra bit transmission is transmitted by selecting the active antenna in each symbol transmission, thus increasing the spectral efficiency. However, active antenna switching in each symbol transmission causes clipping in the signal if the transmitted pulse is span outside its time duration. The effects of the filter span and the roll-off factor on the SM bit error rate were investigated by Monte Carlo simulation. In the simulations, it has been observed that the low roll-off factor value and low filter span increase the bit error.
Location-Based Visible Light Communication
(IEEE, 2023) Çelik, Yasin
Visible light communication (VLC) takes its place among wireless access technologies as an alternative to radio frequency (RF) systems. Although VLC has significant advantages over RF systems (not being affected by electromagnetic interference (EMI), having a wide spectrum range, energy efficiency, etc.), it also has its own problems. One of these problems is the high correlation between channels in multiple-input multiple-output (MIMO) structures. In this paper, a receiver structure with adjustable azimuth and elevation angles is proposed for MIMO VLC. The position of the receiver is determined by means of the receiver signal strength indicator (RSSI) parameter. The best angles were set for the MIMO receiver using positioning data. Repetition coding (RC) and spatial multiplexing (SMP) are used as MIMO schemes and bit error rate (BER) performance is obtained. The proposed receiver structure provides SNR gains at different locations in both schemes.
Hardware-Aware quadrature spatial modulation
(Institute of Electrical and Electronics Engineers Inc., 2022) Çelik, Yasin; Aldırmaz Çolak, Sultan
Spatial modulation (SM) is a simple multi-input multi-output (MIMO) communication technique in which a single transmit antenna is active for each symbol period. Quadrature spatial modulation (QSM), on the other hand, is a form of SM in which independent transmit antenna selection is made for the real and imaginary parts of the symbols. In these techniques, the spectral efficiency (SE) can be increased logarithmically by increasing the number of antennas used on the transmitter-side. Besides, in classical SM and QSM schemes, the number of antennas must be the power of two. In this paper, a flexible QSM scheme is proposed, which eliminates the necessity of antenna number and increases SE value linearly with the number of antennas for RF systems. This scheme, called hardware-aware quadrature spatial modulation (HAQSM), uses optimized constellations for the desired SE value. Optimal constellations are obtained using convex optimization under a constraint aimed at keeping the distance between neighboring symbols above the desired value. The bit error rate (BER) performances of the HAQSM scheme were obtained by Monte Carlo simulations and compared with the existing schemes in the literature.
Indoor visible light communication and positioning with pan-tilt receiver
(Institute of Electrical and Electronics Engineers Inc., 2022) Çelik, Yasin
In recent years, the demand for wireless connectivity and positioning data has increased due to new technologies such as the internet of things (IoT). The wireless connectivity demand has caused spectrum scarcity in the RF bands. For this reason, visible light communication (VLC), which enables overcoming the problem of spectrum shortage especially indoors, has come to the forefront as a complementary technology. The visible light positioning (VLP) technique provides more accurate positioning data compared to their RF counterparts and has lower power consumption indoors. In this paper, VLC and VLP are designed as an integrated system to obtain positioning data at the receiver and improve communication link performance. The triangulation technique built upon the received signal strength indicator (RSSI) is adapted for receiver positioning. A pan-tilt PD is used whose orientation is adjusted to decrease the bit error rate (BER) with the help of positioning information. A multi-input single-output (MISO) system is designed to evaluate the VLCP system performance. Repetition coding (RC) and spatial modulation (SM) is used as MISO schemes. Both schemes have SNR gains at different locations with the help of positioning data.
Low-power and high-speed CMOS voltage buffer for flat panel displays
(Institute of Electrical and Electronics Engineers Inc., 2022) Arslan, Emre; Minali, Shahram
This paper proposes a very low-power and high-speed CMOS voltage buffer for column drivers of flat panel displays. The proposed amplifier circuit employs two complementary input stages and an improved output stage. The proposed circuit draws only 2? quiescent current while a 1nF capacitive load is connected at the output. It has only a 0.82us settling time within a full-swing output. The simulations of the proposed circuit are performed using LTSpice with AMS 0.35?m process parameters and a single 3.3V power supply. It is shown that the circuit has the best Figure-of-Merit value when compared to the previously published solutions.
Human-aware dynamic path planning
(Institute of Electrical and Electronics Engineers Inc., 2021) Korkmaz, Mehmet
This study is related to human-aware navigation (HAN) of a robot moving in a 2D plane. During the navigation process, the robot first finds a global path given start and goal points and it also dynamically scans the environment for possible new obstacles and rearranges its path plan as to those encountered ones. It is well-known fact that treating humans as an ordinary object by robots while passing them leads to humans feeling stressed since the actions of robots still are not explicit for them. For this reason, besides planning strategy secondly, it is also considered whether obstacles are human or non-human ones via the improved algorithm. By doing so, it is aimed for the robot to navigate in an environment considering human comfort. To examine this intention, two different path planning algorithms improved by dynamically classical and human obstacles aware scheme are tested on a home-like environment. According to the results, it has been observed that the robot dynamically plans its navigation framework given target points and new obstacles. Furthermore, it successfully achieves to keep distance from human obstacles based on the proxemics theory distance requirements.
Capacity variation of an indoor MIMO VLC system for a pyramid receiver
(Institute of Electrical and Electronics Engineers Inc., 2020) Khan, Aamir Ullah; Çelik, Yasin; Aldırmaz Çolak, Sultan
In an indoor MIMO visible light communication (VLC) system, LoS links are present between transmitter and receiver. As no fading components are present in an indoor environment, MIMO channels can be highly correlated and a mechanism to reduce channel correlation is essential to enjoy the benefits of the MIMO system. In order to get high multiplexing gain a MIMO system may employ an angle diversity receiver (ADR) in which normal vectors of photodetectors (PDs) point in different directions resulting in an uncorrelated channel matrix. This paper expands the work of a special type of ADR called pyramid receiver (PR) and tries to explore the effect of elevation angles on the capacity of MIMO VLC system. Channel capacity for different field-of-view (FOV) environments is calculated across the entire room using different combinations of PDs elevation angles for a 4x4 MIMO VLC system. Optimum elevation angles resulting in maximum capacity are recorded. Results show that system performance at FOV angle 60 degrees is better as compared to 90 degrees. Results also show that system performance can be improved by allowing each PD to have its own optimum elevation angle but, this comes at a cost of receiver design complexity.
Design and implementation of a novel power conditioner for linear induction launchers
(Institute of Electrical and Electronics Engineers Inc., 2020) Gülpınar, Feyzullah; Balıkçı, Abdulkadir
Abstract Author keywords Indexed keywords Topics of prominence Abstract Linear induction launchers have some important advantages, such as contactless operation between barrel and projectile, over the other type of launching technologies. The barrel corresponding to stator can be excited by generators or capacitor banks whose voltage and frequency might be constant or being manipulated by a power conditioner. Multilevel converter topologies for driving rotational electromechanical machines have attracted more attention for the last decades due to some of their unique benefits. Since linear induction launchers are subset of electrical machines, multilevel topologies can be applied to them as well. For this reason, a novel converter structure as a conditioner for power source unit of a linear induction launcher will be designed and implemented. The proposed power conditioner is constructed as cascaded H-bridge multilevel converter topology in which SiC MOSFETS will be preferred. Level-shifted PWM (LS-PWM) technique is chosen to create required pulses of the switching devices. Also, variable-voltage/variable-frequency (VVVF) control method is applied to drive the launcher with proposed conditioner
Modeling and Simulation of A Photovoltaic Cell Module Controlled with Nonlinear Autoregressive Moving Average-L2 Controller
(Institute of Electrical and Electronics Engineers Inc., 2020) Alkhafaji, Mohammed Ayad; Uzun, Yunus
The photovoltaic cells are deemed one of the most important modern sources of renewable energy due to its direct dependence on solar energy, its low maintenance, and environmental protection. These characteristics led many specialists to study and develop this type of renewable energy. This research paper includes simulations for the design of single-diodes solar cells under the influence of different temperatures and saturation conditions to demonstrate the efficacy of the solar cell. It is also known that the solar cell must be linked to a power controller and here it will be used as an artificial neural network (ANN) technology which is the nonlinear autoregressive moving average (NARMA) by using MATLAB program to control the output power of the PV cell. Hence, the simulation results will show the comparison with and without using the NARMA-L2 controller as a maximum power point tracking (MPPT)
RSSI-Based visible light positioning system with angular diversity receiver
(Institute of Electrical and Electronics Engineers Inc., 2020) Çelik, Yasin
Indexed keywords Topics of prominence Abstract In visible light positioning (VLP) systems based on the received signal strengtll indicator (RSSI), tile re8ected rays from indoor surfaces distort the RSSI information and increase the positioning error. In this study, the angular diversity receiver (ADR) structure is proposed for RSSI based indoor VLP systems and positioning error is investigated together with photo-detector (PD) selection algorithm. Code division multiple access (CDMA) is used as multiplexing technique for data transfer from LEDs. The complexity of the proposed system is low due to the use of RSSI and CDMA. It has been shown that the proposed strucblre improves the mean squared positioning error performance by 10 em for the elevation angle of 60 degree, and reduces the maximum position error by 75 em at points close to the comers and walls
Simulation and control of an electric vehicle by using PSO and specify driving route topology
(Institute of Electrical and Electronics Engineers Inc., 2019) AlKhafaji, Mohammed Ayad; Uzun, Yunus
This paper presents modeling and simulation for a pure electric vehicle with the propulsion chain. The PEV be composed of two electric motors to propulsion the vehicle rear wheels, voltage source inverter, a control system which controls both of motors speed and the electronic differential controller (EDC). Two synchronous reluctance motors represent the propulsion system to the EV. The Particle Swarm Optimization (PSO) is used to specify the optimal parameters of the cascade controllers to control the electric motors. The specify driving route topology has designed and used to test vehicle validity under three different operation conditions. The vehicle system has simulated and tested in the Matlab/Simulink environment.
Analysis of dickson voltage multiplier for RF energy harvesting
(Institute of Electrical and Electronics Engineers Inc., 2019) Al-Azawy, Musaab Mohammed; Sarı, Filiz A.
This paper presents the RF energy harvesting parameters depending on the efficiency and the output DC voltage for input powers between-35dBm to 25dBm. In this study, multi-stage Dickson voltage multiplier (DVM) from 2 to 6-stages are designed and implemented with various load resistance i.e. 20-50-100-500 k? and different matching topology such L-matching, T-matching, and Pi-matching are applied, and also two Schottky diode models (e.g. HSMS-2852 and HSMS-2822) are used to design the DVM to see their effect on the efficiency. All the simulations are done by using the Advance Design System (ADS) 2017. The target frequency selected in the design is 915 MHz for Industrial, Scientific and Medical Radio Band (ISM band). The simulation results show that high efficiency and high output DC voltage are obtained for the DVM circuit design with matching compared to the DVM circuit without matching for low input power.
Simulation and control of photovoltaic panel using Nonlinear autoregressive moving average (NARMA Controller)
(Institute of Physics Publishing, 2019) Harb Najd, Ahmed; Sarı, Filiz A.
Recently, the photovoltaics (PVs) is considers as one of important renewable energy systems. Generally, The PVs cell is detecting the solar radiation and converted it into a power electric DC current. In this paper, the PV has designed to produce power electrical of certain power and it has given that power with standard temperatures conditions designed at (1000 W/m2, 25 °C) for temperature and solar radiation. In case of increase or decrease in the temperature values and solar radiation the power value will be reduced. Besides, the control systems has utilized to control the power value that effected by the radiation and temperature of the PV system. An artificial neural network (ANN) technique which is nonlinear autoregressive moving average (NARMA) has used to the purpose of get the high efficiency and controlling the maximum power point (MPP) at different conditions of radiation and temperature. This control will be carried out by applying a PV model using the equivalent circuit of the PV. MATLAB-based modelling will be used for simulation and compared between results before and after using NARMA controller.
An ontology-based information extraction approach for résumés
(2013) Çelik, Duygu; Elçi, Atilla
A Curriculum Vitae (CV) or a résumé, in general, consists of personal information, education information, work experience, qualifications and preferences parts. Scanning or making structural transformation of the millions of free-formatted résumés from the databases of companies / institutions with human factor will result in the loss of too much time and human effort. In the literature, a limited number of studies have been done to change the résumés of the free-format to a structural format. The overall objective of the study is to infer required information such as user's experience, features, business and education from résumés of the potential user of a human resources system. In this article, we proposed an ontology driven information parsing system that is planned to operate on few millions of résumés to convert them structured format for the purpose of expert finding through the Semantic Web approach. © 2013 Springer-Verlag.
Towards an ınformation extraction system based on ontology to match resumes and jobs
(2013) Çelik, Duygu; Karakaş, A. Aşkın; Bal, Gülşen; Gültunca, Cem; Elçi, Atilla; Buluz, Başak; Alevli, Murat Can
While Internet takes up by far the most significant part of our daily lives, finding jobs/employees on the Internet has started to play a crucial role for job seekers and employers. Online recruitment websites and human resources consultancy and recruitment companies enable job seekers to create their résumé, a brief written formal document including job seeker's basic information such as personal information, educational information, work experience and qualifications in order to find and apply for desirable jobs, whereas they enable companies to find qualified employees they are looking for. However résumés may be written in many ways that make it difficult for online recruitment companies to keep these data in their relational databases. In this study, a project that Kariyer.net (largest online recruitment website in Turkey) and TUBITAK (The Scientific and Technological Research Council of Turkey) have been jointly working is proposed. In this mentioned project, a system enables free structured format of résumés to transform into an ontological structure model. The produced system based on ontological structure model and called Ontology based Résumé Parser (ORP) will be tested on a number of Turkish and English résumés. The proposed system will be kept in Semantic Web approach that provides companies to find expert finding in an efficient way.
A search service for food consumption mobile applications via Hadoop and MapReduce technology
(IEEE, 2016) Çifçi, Mehmet Akif; Ertu?rul, Duygu Çelik; Elçi, Atilla; Reisman, S; Ahamed, SI; Liu, L; Milojicic, D; Claycomb, W; Matskin, M; Sato, H; Nakamura, M; Cimato, S; Lung, CH; Zhang, Z
Many mobile applications on safe food consumption and e-health have been developed recently. Health conscious users highly regard such applications for safe food consumption, especially for avoiding offending foods and additives. However, there is the lack of a comprehensive database containing structured or unstructured data to support such applications. In this paper we propose the MSS, a healthy food consumption search service for mobile applications utilizing Hadoop(1) and MapReduce(2) (MR). The MSS may work as a process behind a mobile application to provide a search service for information on food and food additives. MSS works by the same logic as a search engine (SE); it crawls over Web sources cataloguing relevant information for eventual use in responding to queries from mobile applications. MSS design and development are highlighted in this paper through its system architecture, query understanding, its use of the Hadoop/MapReduce Environment, and action scripts. A case study helps displaying the virtues of MSS.

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