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Conference Object An Approach for Improving Performance of Sensorless Field Control(Ieee, 2018) Ertan, H. Bulent; Filci, TayfunSensorless vector control is preferred in some applications, because there is no need for speed or position sensor. However, by their very nature, they are susceptible to making position error in rotor position estimation. As a consequence the performance of motor drives employing this technology is lower than those which employ sensors. This paper presents a new approach which identifies and uses rotor slot harmonic current component in the stator current to identify rotor position. The time taken by the algorithm used is short enough to be embedded within the vector control algorithm. The essence of the algorithm is treating the current component due to rotor slot harmonics as an amplitude modulated signal on the fundamental current component. The magnitude of this current component is identified via demodulation. Using this information rotor position and speed can be determined. This approach is tested on a commercial induction motor and some results are presented which illustrate that rotor position can be successfully determined.Conference Object Statistical Randomness Tests of Long Sequences by Dynamic Partitioning(Ieee, 2020) Akcengiz, Ziya; Asian, Melis; Karabayir, Ozgur; Doganaksoy, Ali; Uguz, Muhiddin; Sulak, FatihRandom numbers have a wide usage in the area of cryptography. In practice, pseudo random number generators are used in place of true random number generators, as regeneration of them may be required. Therefore because of generation methods of pseudo random number sequences, statistical randomness tests have a vital importance. In this paper, a randomness test suite is specified for long binary sequences. In literature, there are many randomness tests and test suites. However, in most of them, to apply randomness test, long sequences are partitioned into a certain fixed length and the collection of short sequences obtained is evaluated instead. In this paper, instead of partitioning a long sequence into lixed length subsequences, a concept of dynamic partitioning is introduced in accordance with the random variable in consideration. Then statistical methods are applied. The suggested suite, containing four statistical tests: Collision Tests, Weight Test, Linear Complexity Test and Index Coincidence Test, all of them work with the idea of dynamic partitioning. Besides the adaptation of this approach to randomness tests, the index coincidence test is another contribution of this work. The distribution function and the application of all tests are given in the paper.Conference Object Citation - WoS: 2Citation - Scopus: 3Design Considerations for Sub-Ghz Multilayer Microstrip Antenna for Near Ground Communication Links in Rural Areas(Ieee, 2017) Bilgin, Gulsima; Yilmaz, Vadi Su; Aydin, Elif; Kara, Ali; Department of Electrical & Electronics Engineering; Electrical-Electronics EngineeringThis paper presents some preliminary results of design and development of sub-GHz multilayer microstip antenna for use in near ground communication applications. In design stage of the antenna, iterative approach was applied. Firstly, a two layer microstrip antenna design process is presented. Next, the corners of the patch were cut, and a vertical wall on all sides of the antenna were introduced. In this way, both the size and resonant freqeuncy can be tuned. Moreover, as an application specific requirement, it is intended to embed this antenna into a metal box in order to protect it from man-made and natural environmental effects. This was also studied, and effects of the embedding ground on the antenna characteristics were examined. It is shown that the designed antenna provides -27dB resturn loss, and 7.3dB peak gain at 915MHz with the dimension of 150x200x13mm. Some preliminary measurements have proven the simulations.Conference Object Citation - WoS: 13Design of a Robotic Bicopter(Ieee, 2019) Albayrak, Ozge Beyza; Ersan, Yagmur; Bagbasi, Aysen Suheyla; Basaranoglu, Ahmet Turgut; Arikan, Kutluk BilgeThis article presents a Bicopter type of a flying robot with two rotary-wing units which are placed in a tandem form on the chassis. The rotors are tilted by the aid of the tilt mechanism. Cascaded type of PID controllers are designed on the dynamical models for the attitude and altitude dynamics. The simulated control systems are implemented and tuned on the Naze32 flight controller which is connected to a Raspberry Pi single board computer for real-time applications. The real-time performance is monitored and evaluated during the tests and it is seen that the system is suitable for indoor type of robotic applications.Conference Object Citation - WoS: 4Citation - Scopus: 6A Reinforcement Learning Algorithm for Data Collection in Uav-Aided Iot Networks With Uncertain Time Windows(Ieee, 2021) Cicek, Cihan TugrulUnmanned aerial vehicles (UAVs) have been considered as an efficient solution to collect data from ground sensor nodes in Internet-of-Things (IoT) networks due to their several advantages such as flexibility, quick deployment and maneuverability. Studies on this subject have been mainly focused on problems where limited UAV battery is introduced as a tight constraint that shortens the mission time in the models, which significantly undervalues the UAV potential. Moreover, the sensors in the network are typically assumed to have deterministic working times during which the data is uploaded. In this study, we revisit the UAV trajectory planning problem with a different approach and revise the battery constraint by allowing UAVs to swap their batteries at fixed stations and continue their data collection task, hence, the planning horizon can be extended. In particular, we develop a discrete time Markov process (DTMP) in which the UAV trajectory and battery swapping times are jointly determined to minimize the total data loss in the network, where the sensors have uncertain time windows for uploading. Due to the so-called curse-of-dimensionality, we propose a reinforcement learning (RL) algorithm in which the UAV is trained as an agent to explore the network. The computational study shows that our proposed algorithm outperforms two benchmark approaches and achieves significant reduction in data loss.Conference Object Citation - WoS: 1Sustainable Software Engineering: a Move Towards Future(Ieee, 2017) Mishra, Alok[No Abstract Available]Conference Object Citation - WoS: 1An Undergraduate Curriculum for Deep Learning(Ieee, 2018) Tirkes, Guzin; Ekin, Cansu Cigdem; Sengul, Gokhan; Bostan, Atila; Karakaya, MuratDeep Learning (DL) is an interesting and rapidly developing field of research which has been currently utilized as a part of industry and in many disciplines to address a wide range of problems, from image classification, computer vision, video games, bioinformatics, and handwriting recognition to machine translation. The starting point of this study is the recognition of a big gap between the sector need of specialists in DL technology and the lack of sufficient education provided by the universities. Higher education institutions are the best environment to provide this expertise to the students. However, currently most universities do not provide specifically designed DL courses to their students. Thus, the main objective of this study is to design a novel curriculum including two courses to facilitate teaching and learning of DL topic. The proposed curriculum will enable students to solve real-world problems by applying DL approaches and gain necessary background to adapt their knowledge to more advanced, industry-specific fields.Conference Object Citation - WoS: 13A Decentralized Application for Secure Messaging in a Trustless Environment(Ieee, 2018) Abdulaziz, Mohamed; Culha, Davut; Yazici, AliBlockchain technology has been seeing widespread interest as a means to ensure the integrity, confidentiality and availability of data in a trustless environment. They are designed to protect data from both internal and external cyberattacks by utilizing the aggregated power of the network to resist malicious efforts. In this article, we will create our own decentralized messaging application utilizing the Ethereum Whisper protocol. Our application will be able to send encrypted messages both securely and anonymously. We will utilize the Ethereum platform to deploy our blockchain network. This application would be resistant to most suppression tactics due to its distributed nature and adaptability of its communication protocol.Conference Object Shape Recognition With Low Cost Sensors(Ieee, 2018) Saloglu, Keziban; Hosafci, Arda; Birbilen, Merve; Bulut, Yigit A.; Gunes, AhmetThis paper proposes a method to recognize the shape of some objects that have different geometrical properties using an infra-red sensor.To that end, a mechanism that has two degrees of freedom is designed. Scanning of the different objects are obtained. Noise on scanning output is removed. Finally, all the outputs for different objects are discussed to obtain the specifications to do shape recognition.Conference Object Citation - WoS: 2Magnetically Geared Direct Drive Wind Generator Thermal Analysis(Ieee, 2017) Zeinali, Reza; Ertan, H. Bulent; Yamali, Cemil; Tarvirdilu-Asl, RasulThis paper considers Dual Stator Spoke Array Vernier Permanent Magnet (DSSA-VPM) generator for the direct drive wind-electric energy conversion. The structure of the generator is described. Although how this design is optimized is not discussed, dimensions of the designed generator are given. In electrical machine design thermal performance is naturally of utmost importance. In this paper thermal performance of the design and how its temperature can be kept within the temperature limit imposed by its insulation class and the permanent magnets used is investigated. It is found that when air flow within the generator is not permitted, at rated load condition the generator temperature reaches very high levels. To lower the operating temperature, ventilation holes are introduced to the end plates of the frame. Also some blades are placed on the rotor to help flow of air over the end windings. A model is introduced to calculate the air speed in the region where air flows. Using the calculated air speed a new heat transfer coefficient is determined for the region where air flows. It is found out that with the mentioned modifications to the structure of the generator the designed generator temperature rise can be kept within the value permitted for its insulation class. Therefore, the power density of the design can be safely compared with the power density of other types of designs for direct drive turbines. It is found that DSSA-VPM generator topology offers a clear advantage over other types of generators considered in the literature.
