On The Design Of Equal Division Single-Band Filtering Dividers With An Extended Transmission Line And Resistor As Isolation Elements, Zafar Bedar Khan, Huiling Zhao
Turkish Journal of Electrical Engineering and Computer Sciences
This paper introduces a new scheme for effective output port isolation and return loss in RF-filtering divider design. The proposed design incorporates an extended transmission line and a conventional resistor as isolation elements. The technique has a simpler microstrip circuit implementation when it comes to the integration of a single-band band-pass filter with a Wilkinson power divider to achieve simultaneous filtering-dividing action. It is established that if a band-pass filter with a certain fractional-bandwidth is matched to 70.7 $\Omega $, a transmission line section and isolation resistor are sufficient for achieving reasonable output port return loss and isolation in the …
New Patterson-Wiedemann Type Functions With 15 Variables In The Generalized Rotation-Symmetric Class,
2017
TÜBİTAK
New Patterson-Wiedemann Type Functions With 15 Variables In The Generalized Rotation-Symmetric Class, Selçuk Kavut
Turkish Journal of Electrical Engineering and Computer Sciences
Recently, it was shown that there is no Boolean function on 15 variables with nonlinearity greater than 16276 in the class of functions that are invariant under the action of GF(2$^{3})^{\ast }\times GF(2^{5})^{\ast }$. In this study, we consider some important subsets of this class and perform an efficient enumeration of the 15-variable Patterson-Wiedemann (PW) type functions with nonlinearity greater than the bent concatenation bound 16256 in the generalized classes of both 3-RSBFs and 5-RSBFs for which the corresponding search spaces are 2$^{28.2}$ and 2$^{47.85}$, respectively. For the case of 3-RSBFs, we find that there are 32 functions with nonlinearity …
Effect Of Stator Permanent Magnet Thickness And Rotor Geometry Modifications On The Minimization Of Cogging Torque Of A Flux Reversal Machine, Bheeman Vidhya, Kandadai Nagaratnam Srinivas
Turkish Journal of Electrical Engineering and Computer Sciences
This paper attempts to examine the effect of stator-rotor geometry on the minimization of cogging torque of a flux reversal generator (FRG). With respect to stator geometry, height (or thickness) of the permanent magnets of the stator poles was varied and cogging torque minimization was observed. With respect to rotor geometry, the following cases were considered: a) rotor pole arc variation and b) V-shaped punches on the rotor pole. The characterization of FRG under these cases for the observation of the effects on cogging torque was performed using three-dimensional finite element analysis. From the results of simulation, a model was …
Probabilistic Day-Ahead System Marginal Price Forecasting With Ann For The Turkish Electricity Market,
2017
TÜBİTAK
Probabilistic Day-Ahead System Marginal Price Forecasting With Ann For The Turkish Electricity Market, Erdem Özgüner, Osman Bülent Tör, Ali̇ Nezi̇h Güven
Turkish Journal of Electrical Engineering and Computer Sciences
This study presents a system day-ahead hourly market clearing price forecasting tool for the day-ahead (DA) market and a system DA hourly marginal price forecasting tool for the real-time market of the Turkish electric market (TEM). These forecasting tools are developed based on artificial neural networks (ANNs). A series of historical price data of the TEM are utilized to model and optimize the ANN structure and to develop the ANN-based price forecasting tool. The methodology used to select the optimum ANN architecture provides the minimum daily mean absolute percentage error for both day-ahead market prices in the TEM. Performances of …
Horizontal Directional Drilling Pilot Bore Simulation,
2017
TÜBİTAK
Horizontal Directional Drilling Pilot Bore Simulation, Paulius Tervydis, Ruta Jankuniene
Turkish Journal of Electrical Engineering and Computer Sciences
Various underground communications (water or gas supply systems, sewage, power lines) have been installed in recent years using trenchless technologies, i.e. horizontal directional drilling (HDD). This technique by its nature does not disturb the traffic and is environmentally friendly. One must be aware that, with HDD, pipeline building time is shortened. With respect to the above, HDD is especially effective in highly populated or industrial areas. However, it is necessary to ensure that HDD works, in order to prevent damage to installed underground facilities. The aim of this work is to propose a user-friendly and inexpensive simulation tool with required …
Mri Image Enhancement Using Biot-Savart Law At 3 Tesla,
2017
TÜBİTAK
Mri Image Enhancement Using Biot-Savart Law At 3 Tesla, Yunus Emre Esi̇n, Ferda Nur Alpaslan
Turkish Journal of Electrical Engineering and Computer Sciences
Coil sensitivity is considered as the most valuable data in the parallel reconstruction of magnetic resonance imaging (MRI). In this study, a novel coil sensitivity map extraction method is introduced for spatially fixed phased array coils. The proposed technique uses the Biot--Savart law with coil internal shape information and low-resolution phase image data to form sensitivity maps. The performance of this method is tested in a parallel image reconstruction task, using the sensitivity-encoding (SENSE) technique. Under the quasi-static assumption and using the duality principle, we computed the sensitivity maps of a phased-array head coil and reconstructed full FOV images. The …
A Stable Marriage-Based Request Routing Framework For Interconnection Cdns,
2017
TÜBİTAK
A Stable Marriage-Based Request Routing Framework For Interconnection Cdns, Bo Huang, Lijian Zou, Xiaowen Tong, Xiaoqun Yuan
Turkish Journal of Electrical Engineering and Computer Sciences
Content delivery network (CDN) interconnection is a promising solution to addressing the limited service scale of CDNs. It scales the CDN's service footprint through the cooperation of CDNs without significantly changing the existing network architecture. However, in a CDN interconnection system, CDNs are independent of each other and each pursues its own goals, which means that cooperation is hard to establish and easy to break. In our paper, we propose a stable marriage-based routing framework to establish a strong cooperation service for CDNs and to select the `optimal' server for each request among the cooperative CDNs. To this end, we …
A Fast Feature Selection Approach Based On Extreme Learning Machine And Coefficient Of Variation,
2017
TÜBİTAK
A Fast Feature Selection Approach Based On Extreme Learning Machine And Coefficient Of Variation, Ömer Faruk Ertuğrul, Mehmet Emi̇n Tağluk
Turkish Journal of Electrical Engineering and Computer Sciences
Feature selection is the method of reducing the size of data without degrading their accuracy. In this study, we propose a novel feature selection approach, based on extreme learning machines (ELMs) and the coefficient of variation (CV). In the proposed approach, the most relevant features are identified by ranking each feature with the coefficient obtained through ELM divided by CV. The achieved accuracies and computational costs, obtained with the use of features selected via the proposed approach in 9 classification and 26 regression benchmark data sets, were compared to those obtained with all features, as well as those obtained with …
Relaxation Rate And Polarization Charge Density Model For Aln/Al$_{X}$Ga$_{1 - X}$N/Aln Heterostructures,
2017
TÜBİTAK
Relaxation Rate And Polarization Charge Density Model For Aln/Al$_{X}$Ga$_{1 - X}$N/Aln Heterostructures, Nagarajan Sivarajan, Reeba Korah, Mariya Kalavathy Ganamani
Turkish Journal of Electrical Engineering and Computer Sciences
This work describes the strain-relaxation--dependent carrier concentration ($n_{s})$ profile model using spontaneous and piezoelectric polarization for AlN/Al$_{x}$Ga$_{1 - x}$N/AlN HEMTs in all mole fraction ($x)$ interpolations. As $x$ varies, the Aluminum Gallium Nitride (AlGaN) channel shows strain relaxation with the Aluminum Nitride (AlN) barrier. The degree of relaxation is modeled from AlN to GaN regions in the channel. It shows that the AlN barrier and buffer relaxation and strain recovery occurs due to the gradual crystal quality degradation from barrier/buffer to the channel interface. These combination devices show less drain current degradation with temperature variation from 300 K to 573 …
Axial Flux Pm Bldc Motor Design Methodology And Comparison With A Radial Flux Pm Bldc Motor,
2017
TÜBİTAK
Axial Flux Pm Bldc Motor Design Methodology And Comparison With A Radial Flux Pm Bldc Motor, Ertuğrul Yeşi̇lbağ, Yasemi̇n Ertuğrul, Lale Ergene
Turkish Journal of Electrical Engineering and Computer Sciences
The aim of this paper is to develop a methodology to design an axial flux permanent magnet brushless direct current (AFPM) motor for a washing machine and compare the results with a conventional radial flux permanent magnet brushless direct current (RFPM) motor with the same power ratings. The AFPM motor is designed based on the maximum power density for an optimum inner-to-outer diameter ratio by using the reference RFPM motor constraints, such as the same rated torque at the rated speed. Both motors use the same materials in terms of lamination, permanent magnet, and conductor. They both use ferrite magnets; …
Comparative Study For Identification Of Multiple Alarms In Telecommunication Networks,
2017
TÜBİTAK
Comparative Study For Identification Of Multiple Alarms In Telecommunication Networks, Ati̇la Yilmaz
Turkish Journal of Electrical Engineering and Computer Sciences
Telecommunication networks consist of communication units interconnected physically or by means of protocols in order to provide basic services like data, voice, or image transfers. In this study, a modeling frame for network units and their links in a topological frame is presented based on a real mobile communication network named TASMUS (TAktik Saha MUharebe Sistemi - Tactical Field Combat System). Alarm handling is one of the most critical features required in communication networks. Based on simulated single alarm and multiple (double) alarm scenarios, known powerful alarm estimation approaches, namely the coding method, neural networks, and knowledge-based systems, have been …
Modeling Hybrid Modulation Strategy With Nearest Leveled Vector Switching Pattern In Space Vector Control Technique For Multilevel Inverters, Rohith Balaji Jonnala, Sai Babu Choppavarapu
Turkish Journal of Electrical Engineering and Computer Sciences
The multilevel inverter's impact in the area of power electronics is augmented because of its nimble nature. This paper presents an efficient switching pattern for multilevel inverters using the nearest leveled vector (NLV) strategy through a space vector control (SVC) technique. The objective is to reduce the total harmonic distortions by generating an optimal switching sequence with the newly introduced NLV-SVC for multilevel inverters. The proposed NLV modulation is applied for an asymmetrical multilevel inverter, which has a high number of levels with reduced switch count, sources, and lower switching losses. The effectiveness of the proposed method is verified on …
Multitier Decentralized Control Scheme Using Energy Storage Unit And Load Management In Inverter-Based Ac Microgrids,
2017
TÜBİTAK
Multitier Decentralized Control Scheme Using Energy Storage Unit And Load Management In Inverter-Based Ac Microgrids, Sara Nourollah, Abolfazl Pirayesh, Matthias Fripp
Turkish Journal of Electrical Engineering and Computer Sciences
The use of renewable energies, such as wind and solar, is rising in microgrids. However, because of their intermittent nature, achieving a stable system in spite of the fluctuations of generation and demand is very difficult. Aiming to increase the stability margin of AC islanded microgrids comprising nondeterministic resources, properly share real power (P), and keep the network frequency ($f)$ at nominal value, this study exploits the presence of energy storage units (ESUs) along with a load-shedding scheme. To this end, this study proposes a multitier decentralized control strategy that is based on frequency and includes three control schemes, distributed …
Turkish Synonym Identification From Multiple Resources: Monolingual Corpus, Mono/Bilingual Online Dictionaries, And Wordnet,
2017
TÜBİTAK
Turkish Synonym Identification From Multiple Resources: Monolingual Corpus, Mono/Bilingual Online Dictionaries, And Wordnet, Tuğba Yildiz, Banu Di̇ri̇, Savaş Yildirim
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a model is proposed to determine synonymy by incorporating several resources. The model extracts the features from monolingual online dictionaries, a bilingual online dictionary, WordNet, and a monolingual Turkish corpus. Once it has built a candidate list, it determines the synonymy for a given word by means of those features. All these resources and the approaches are evaluated. Taking all features into account and applying machine learning algorithms, the model shows good performance of F-measure with 81.4%. The study contributes to the literature by integrating several resources and attempting the first corpus-driven synonym detection system for Turkish.
A Modified Genetic Algorithm For A Special Case Of The Generalized Assignment Problem,
2017
TÜBİTAK
A Modified Genetic Algorithm For A Special Case Of The Generalized Assignment Problem, Murat Dörterler, Ömer Faruk Bay, Mehmet Ali̇ Akcayol
Turkish Journal of Electrical Engineering and Computer Sciences
Many central examinations are performed nationwide in Turkey. These examinations are held simultaneously throughout Turkey. Examinees attempt to arrive at the examination centers at the same time and they encounter problems such as traffic congestion, especially in metropolises. The state of mind that this situation puts them into negatively affects the achievement and future goals of the test takers. Our solution to minimize the negative effects of this issue is to assign the test takers to closest examination centers taking into account the capacities of examination halls nearby. This solution is a special case of the generalized assignment problem (GAP). …
Design And Walking Pattern Generation Of A Biped Robot,
2017
TÜBİTAK
Design And Walking Pattern Generation Of A Biped Robot, Tolga Olcay, Ahmet Özkurt
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents the design of a biped robot, the walking trajectory generation method, and experimental results about biped walking. Walking trajectory generation is one of the deterministic factors in walking robot applications. Different approaches for stable walking trajectory are worked on in robotic research. The linear inverted pendulum model (LIPM) is an effective method used with the zero moment point (ZMP) criteria. Biped robot trunk and feet moving patterns are generated depending on these fundamental methods. In this study, generated trajectories were tested by a 12 degree of freedom (DOF) biped robot RUBI built at Dokuz Eylül University. In …
Transient State Estimation With The Bergeron Transmission Line Model,
2017
TÜBİTAK
Transient State Estimation With The Bergeron Transmission Line Model, Naret Suyaroj, Suttichai Premrudeepreechacharn, Neville Robert Watson
Turkish Journal of Electrical Engineering and Computer Sciences
Transient state estimation (TSE) was used to determine the state values that have no measurement equipment placed in an electric power system with transient phenomena. Previous papers used the PI model for TSE with a short transmission line, but longer lines require the development of algorithms that include the distributed parameters of transmission lines with the Bergeron model. The test system was a 10-bus power system. The simulated transient was caused by a fault event, resulting in different persistent voltage drops that ranged from 10% to 90% at selected buses. In addition, noises were applied to evaluate the algorithm, which …
A New Mechanism To Improve Video Streaming In P2p Networks Using Helper Nodes,
2017
TÜBİTAK
A New Mechanism To Improve Video Streaming In P2p Networks Using Helper Nodes, Javid Kargar, Abdorasoul Ghasemi
Turkish Journal of Electrical Engineering and Computer Sciences
Peer-to-peer video on demand (P2P-VoD) is a solution to provide video service to a large number of users on the Internet. Due to the upload bandwidth bottleneck of VoD servers, the streaming capacity in the P2P-VoD system is limited. This paper proposes a new mechanism to improve the video streaming in P2P networks by using the idle peers upload bandwidth and storage, which are called helpers. The proposed method uses an XOR mechanism in the VoD server to encode chunks and reduce bandwidth use. The helpers receive encoded chunks from the VoD server and save them in their storage spaces …
Classifications Of Disturbances Using Wavelet Transform And Support Vector Machine,
2017
TÜBİTAK
Classifications Of Disturbances Using Wavelet Transform And Support Vector Machine, Neda Hajibandeh, Faramarz Faghihi, Hossein Ranjbar, Hesam Kazari
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes a new method to detect and classify all kinds of faults, capacitor switching, and load switching in a power system network based on wavelet transform and support vector machines (SVMs). In this regard, a sample of a power system is simulated via MATLAB/Simulink, and by reading the voltage of the point of common coupling and using the wavelet transform, the differences of the outputs of the wavelet transform are investigated. The SVM approach is employed to distinguish the type of the transient (capacitor switching, fault, and/or load switching) in use for the high level outputs of the …
A Self-Tuning Neurofuzzy Feedback Linearization-Based Damping Control Strategy For Multiple Hvdc Links,
2017
TÜBİTAK
A Self-Tuning Neurofuzzy Feedback Linearization-Based Damping Control Strategy For Multiple Hvdc Links, Saghir Ahmad, Laiq Khan
Turkish Journal of Electrical Engineering and Computer Sciences
This research work proposes a multi-input multi-output (MIMO) online adaptive feedback linearization NeuroFuzzy control (AFLNFC) scheme to improve the damping of low frequency oscillations (LFOs) in an AC/DC power system. Optimized NeuroFuzzy identification architecture online captures the oscillatory dynamics of the power system through wide area measurement system (WAMS)-based measured speed signals of machines. Based on the identified power system model, the appropriate control law is derived through feedback linearization control with a self-tuned coefficient vector. The generated control signal modulates the real power flow through a high voltage direct current (HVDC) link during perturbed operating conditions and enhances system …
