Physical Sciences and Mathematics Commons^™

Model-Reference Sliding Mode Control Of A Three-Phase Four-Leg Voltage Source Inverter For Stand-Alone Distributed Generation Systems, Ayhan Özdemi̇r, İrfan Yazici, Zeki̇ye Erdem

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a discrete-time model-reference sliding mode control of three-phase four-leg voltage source inverters for stand-alone distributed generation systems. Three-phase four-leg voltage source inverters (VSIs) are used in a broad area. A discrete-time model-reference sliding mode controller, having superior advantages such as insensitivity to external disturbances, system parameter variations, and modeling errors, is applied to control the output voltage of three-phase four-leg VSIs. As a new study, the discrete-time model-reference sliding mode control with a supplemented output feedback integral controller is proposed so that the controlled output voltages of the VSI tracks the input reference signal. The controller is …

Performance Analysis Of A 500-Kwp Grid-Connected Solar Photovoltaic Power Plant In Kahramanmaraş, Şaban Yilmaz, Hasan Riza Özçalik

Turkish Journal of Electrical Engineering and Computer Sciences

In today's world, the daily need for and cost of energy sources increase and this forces industrial institutions to seek for new ways to generate their own energy. The developments in photovoltaic systems have recently drawn attention in the business world. Although their installation costs are high, they are environmentally friendly and profitable investments in the long run. The cost analysis of a large-scale photovoltaic generator in the climatic conditions of Kahramanmara\c{s} will lead the way to new investments. In this study, the modeling and cost analysis of an on-grid photovoltaic generator of 500 kW, which was installed to provide …

Speech Emotion Recognition Using Nonlinear Dynamics Features, Ali Shahzadi, Alireza Ahmadyfard, Ali Harimi, Khashayar Yaghmaie

Turkish Journal of Electrical Engineering and Computer Sciences

Recent developments in man--machine interaction have motivated researchers to recognize human emotion from speech signals. In this study, we propose using nonlinear dynamics features (NLDs) for emotion recognition. NLDs are extracted from the geometrical properties of the reconstructed phase space of speech signals. The traditional prosodic and spectral features are also used as a benchmark. The Fisher discriminant ratio acts as a filter to remove irrelevant features quickly. Then a wrapper method based on a genetic algorithm and support vector machine is employed to find the best feature subset that obtains the maximum recognition rate. The classification accuracy of the …

Lattice Approach To Video Steganography, Onur Ünlü, Hacer Karacan

Turkish Journal of Electrical Engineering and Computer Sciences

As a result of the continuously increasing amount of important data, the demand for information security increases daily. Steganographic techniques can play a considerable role in solving this issue, since they can hide the necessary data. Generally, audio and image files have been utilized as hiding media in this area. However, because of their limited capacity, these media limit the amount of hidden information. On the other hand, the capacity limit can be exceeded by applying steganography on video files. There are few studies on video steganography in the literature. In this study, a steganographic library, which is independent of …

A Comparative Study Of Two Different Fpga-Based Arrhythmia Classifier Architectures, Ahmet Turan Özdemi̇r, Kenan Danişman

Turkish Journal of Electrical Engineering and Computer Sciences

Early diagnosis of dangerous heart conditions is very important for the treatment of heart diseases and for the prevention of sudden cardiac death. Automatic electrocardiogram (ECG) arrhythmia classifiers are essential to timely diagnosis. However, most of the medical diagnosis systems proposed in the literature are software-based. This work focused on the hardware implementation of a mobile artificial neural network (ANN)-based arrhythmia classifier that is implemented on a field programmable gate array (FPGA) as a single chip solution, as an alternative to various software models of ANNs. Due to the parallel nature of ANNs, hardware implementation of ANNs needs a large …

Comparison Of Clustering Techniques For Traffic Accident Detection, Nejdet Doğru, Abdülhami̇t Subaşi

Turkish Journal of Electrical Engineering and Computer Sciences

Transportation infrastructure in intelligent transportation systems (ITSs) is complemented with information and communication technologies to achieve better passenger safety and reduced transportation time, fuel consumption, and vehicle wear and tear. This paper shows how data mining techniques are used in ITSs for accident detection and prevention on motorways. In traffic, vehicles show similar behavior to that of vehicles in closed neighborhoods. Vehicles that show different behaviors than neighbor vehicles in cases like accidents, inappropriate lane changes, and speeding can be considered as anomalies and detected. In this paper, a traffic accident is simulated and the effectiveness of different clustering techniques …

Grounded Capacitor-Based New Floating Inductor Simulators And A Stability Test, Erkan Yuce, Sezai̇ Tokat, Hali̇l Alpaslan

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, two new floating inductor simulators (FISs), both using two differential difference current conveyors, are considered. The proposed FISs do not suffer from passive component matching constraints and employ a minimum number of passive elements. They use a grounded capacitor; accordingly, they are suitable for integrated circuit technology. They have good low- and high-frequency performances. Simulations are performed with the SPICE program to verify the claimed theory. Moreover, for the first FIS used in a second-order low-pass filter, a stability test is performed as an example.

Central Coordination Relay For Distribution Systems With Distributed Generation, Fati̇h Mehmet Nuroğlu, Ayşen Basa Arsoy

Turkish Journal of Electrical Engineering and Computer Sciences

As distributed generation resources penetrate into distribution systems, protection and service continuity are becoming major issues. A new approach for protection coordination and higher reliability of a distribution system with distributed generation is explored in this paper. The concept of central coordination relay (CCR) is developed for this purpose. After a brief introduction of the design and operating procedures of CCR, the utilization of the proposed relay on two feeders of a substation in the Kocaeli region of Turkey is simulated using DIgSILENT PowerFactory. The study results show that CCR can provide better protection coordination and improved reliability indices for …

Dual Open-End Stator Winding Induction Machine Fed By Redundant Voltage Source Inverters, Sami Guizani, Faouzi Ben Ammar

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the authors propose the availability analysis of a dual open-end stator windings asynchronous machine. Each open-end stator winding is supplied by two PWM voltage source inverters. The active and passive redundancy of the inverters improves reliability, availability, and safety of the system since the loss of inverter losses does not stop the machine. Indeed, for active redundancy, in the case of failure of the inverter, the corresponding winding is disconnected and the other winding is supplied by the two healthy inverters. For passive redundancy, one winding is fed by two inverters and the two others are waiting; …

The Simulation And Production Of Glow Plugs Based On Thermal Modeling, Mustafa Saci̇d Endi̇z, Muci̇z Özcan, Mehmet Aki̇f Eri̇şmi̇ş, Mustafa Yağci, Hi̇dayet Günay

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, we present the thermal behavior of a glow plug examined with thermal impedance modeling. The circuit model is based on the analogy of thermal and electrical domains and expresses the glow plug used in diesel engines to preheat the air-diesel fuel mixture. In this study, the circuit design, implementation, and simulation of a glow plug for diesel engines are illustrated. In order to verify this thermal model, 2 different glow plugs are produced. The test results of the glow plugs produced in this study show complete agreement with the simulation results. It is thought that this circuit-based …

Bull Optimization Algorithm Based On Genetic Operators For Continuous Optimization Problems, Oğuz Findik

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the researcher proposes a new evolutionary optimization algorithm that depends on genetic operators such as crossover and mutation, referred to as the bull optimization algorithm (BOA). This new optimization algorithm is called the BOA because the best individual is used to produce offspring individuals. The selection algorithm used in the genetic algorithm (GA) is removed from the proposed algorithm. Instead of the selection algorithm, individuals initially produced attempt to achieve better individuals. In the proposed method, crossover operation is always performed by using the best individual. The mutation process is carried out by using individual positions. In …

Ga Based Adaptive Receiver For Mc-Cdma System, Muhammad Adnan Khan, Muhammad Umair, Muhammad Aamer Saleem Choudhry

Turkish Journal of Electrical Engineering and Computer Sciences

Multicarrier systems like the multicarrier code division multiple access (MC-CDMA) systems are designed for maximum usability of available bandwidth. We use the MC-CDMA system with Alamouti's space time coding in this paper. We propose the genetic algorithm (GA) in order to calculate MC-CDMA receiver weights with two variation schemes. The proposed schemes reduce receiver complexity. The bit error rate and convergence rate are also improved by increasing the number of genes and chromosomes of the GA in both schemes as compared with conventional LMS based receivers of the MC-CDMA system. This is verified via simulations.

Research On Heat Dissipation And Cooling Optimization Of A Power Converter In Natural Convection, Yang Xu, Hao Chen, Zhentao Hu, Hui Zeng, Qianlong Wang

Turkish Journal of Electrical Engineering and Computer Sciences

A thermal model for the power converter in a switched reluctance motor drive under natural air cooling is presented. In this compact model, the modeling of the power device is simplified reasonably. Based on the computational fluid dynamics and finite element tools, the thermal and fluid characteristics of the power converter are obtained. The experiment platform is then established, which verifies the correctness of the simulation model. To increase the reliability of the power converter, the layouts of devices on the heat sink and the placement direction of the heat sink are optimized without changing the heat sink shape. Four …

An Isomorphism Problem In Z2, Matt Noble

Theory and Applications of Graphs

We consider Euclidean distance graphs with vertex set ℚ² or ℤ² and address the possibility or impossibility of finding isomorphisms between such graphs. It is observed that for any distances d₁, d₂ the non-trivial distance graphs G(ℚ², d₁) and G(ℚ², d₂) are isomorphic. Ultimately it is shown that for distinct primes _p1, _p2 the non-trivial distance graphs G(ℤ², √p1) and G(ℤ², √p2) are not isomorphic. We conclude with a few additional questions related to this work.

Properly Colored Notions Of Connectivity - A Dynamic Survey, Xueliang Li, Colton Magnant

Theory and Applications of Graphs

A path in an edge-colored graph is properly colored if no two consecutive edges receive the same color. In this survey, we gather results concerning notions of graph connectivity involving properly colored paths.

Second Hamiltonian Cycles In Claw-Free Graphs, Hossein Esfandiari, Colton Magnant, Pouria Salehi Nowbandegani, Shirdareh Haghighi

Theory and Applications of Graphs

Sheehan conjectured in 1975 that every Hamiltonian regular simple graph of even degree at least four contains a second Hamiltonian cycle. We prove that most claw-free Hamiltonian graphs with minimum degree at least 3 have a second Hamiltonian cycle and describe the structure of those graphs not covered by our result. By this result, we show that Sheehan’s conjecture holds for claw-free graphs whose order is not divisible by 6. In addition, we believe that the structure that we introduce can be useful for further studies on claw-free graphs.

Bounds For The Zero Forcing Number Of Graphs With Large Girth, Randy Davila, Franklin Kenter

Theory and Applications of Graphs

The zero-forcing number, Ζ(G) is an upper bound for the maximum nullity of all symmetric matrices with a sparsity pattern described by the graph. A simple lower bound is δ ≤ Ζ(G) where δ is the minimum degree. An improvement of this bound is provided in the case that G has girth of at least 5. In particular, it is shown that 2δ − 2 ≤ Ζ(G) for graphs with girth of at least 5; this can be further improved when G has a small cut set. Lastly, a conjecture is made regarding a lower bound for Ζ(G) as a …

Dynamic Approach To K-Forcing, Yair Caro, Ryan Pepper

Theory and Applications of Graphs

The k-forcing number of a graph is a generalization of the zero forcing number. In this note, we give a greedy algorithm to approximate the k-forcing number of a graph. Using this dynamic approach, we give corollaries which improve upon two theorems from a recent paper of Amos, Caro, Davila and Pepper [2], while also answering an open problem posed by Meyer [9].

Scheduling N Burgers For A K-Burger Grill: Chromatic Numbers With Restrictions, Peter Johnson, Xiaoya Zha

Theory and Applications of Graphs

The chromatic number has a well-known interpretation in the area of scheduling. If the vertices of a finite, simple graph are committees, and adjacency of two committees indicates that they must never be in session simultaneously, then the chromatic number of the graph is the smallest number of hours during which the committees/vertices of the graph may all have properly scheduled meetings of one continuous hour each. Slivnik [3] showed that the fractional chromatic number can be similarly characterized. In that characterization, the meetings are allowed to be broken into a finite number of disjoint intervals. Here we consider chromatic …

Connection And Separation In Hypergraphs, Mohammad A. Bahmanian, Mateja Sajna

Theory and Applications of Graphs

In this paper we study various fundamental connectivity properties of hypergraphs from a graph-theoretic perspective, with the emphasis on cut edges, cut vertices, and blocks. We prove a number of new results involving these concepts. In particular, we describe the exact relationship between the block decomposition of a hypergraph and the block decomposition of its incidence graph.

The Challenges Of Being Chair In 2015: A 28 Year Perspective, Domenick Pinto

School of Computer Science & Engineering Faculty Publications

For 28 years as chair, I have witnessed the evolution of the role of chairperson as entrepreneurial skills, conflict resolution and time management have become increasingly vital to the success of the chair. My session will summarize the challenges that chairs must now face and overcome in 2015. The session will help relatively new and new chairs face scenarios and how to problem solve them.

Wearable Computing: Interface, Emotions And The Wearer's Culture, Robert Mccloud, Martha B. Lerski

School of Computer Science & Engineering Faculty Publications

Wearable computing offers an interesting subset for the mobile computing field. While Google Glass might not yet have found the mass audience it sought, other, simpler, wearable devices have made an impact. This paper presents results of a four-week long experiment in how subjects interact and emotionally respond to the Fitbit Flex. Users tracked daily totals of steps, distance traveled, minutes active, calories burned, and time slept. They also found their own personal uses for the Fitbit interface. Users were asked to be aware of and report their emotional reactions by keeping continuous, daily journals. A popular and relatively inexpensive …

Augmented Reality All Around Us: Power And Perception At A Crossroads, Marty J. Wolf, Frances Grodzinsky

School of Computer Science & Engineering Faculty Publications

In this paper we continue to explore the ethics and social impact of augmented visual field devices (AVFDs). Recently, Microsoft announced the pending release of HoloLens, and Magic Leap filed a patent application for technology that will project light directly onto the wearer’s retina. Here we explore the notion of deception in relation to the impact these devices have on developers, users, and non-users as they interact via these devices. These sorts of interactions raise questions regarding autonomy and suggest a strong need for informed consent protocols. We identify issues of ownership that arise due to the blending of physical …

Old Dogs, New Tricks, Mark S. Peterson, Nancy J. Brown-Peterson

Gulf and Caribbean Research

No abstract provided.

Introductory Texts

Proceedings of the Annual Meeting of the Georgia Association of Mathematics Teacher Educators

• GAMTE 2015 Officers
• GAMTE 2015 Conference Committee
• GAMTE 2015 Proceeding Committee
• Purposes and Goals of GAMTE
• Letter from the President
• Table of Contents

Split Extension Classifiers In The Category Of Precrossed Modules Of Commutative Algebras, Yaşar Boyaci, Tufan Sai̇t Kuzpinari, Enver Önder Uslu

Turkish Journal of Mathematics

We construct an actor of a precat$^{1}$-algebra and then by using the natural equivalence between the categories of precat$^{1}$-algebras and that of precrossed modules, we construct the split extension classifier of the corresponding precrossed module, which gives rise to the representability of actions in the category of precrossed modules of commutative algebras under certain conditions.

On Condition $(Pwp)_{W}$ For $S$-Posets, Xingliang Liang, Yanfeng Luo

Turkish Journal of Mathematics

Golchin and Rezaei (Commun Algebra 2009; 37: 1995--2007) introduced the weak version of Condition $(PWP)$ for $S$-posets, called Condition $(PWP)_{w}$. In this paper, we continue to study this condition. We first present a necessary and sufficient condition under which the $S$-poset $A(I)$ satisfies Condition $(PWP)_{w}$. Furthermore, we characterize pomonoids $S$ over which all cyclic (Rees factor) $S$-posets satisfy Condition $(PWP)_{w}$, and pomonoids $S$ over which all Rees factor $S$-posets satisfying Condition $(PWP)_{w}$ have a certain property. Finally, we consider direct products of $S$-posets satisfying Condition $(PWP)_{w}$.

The Iteration Digraphs Of Finite Commutative Rings, Yangjiang Wei, Gaohua Tang

Turkish Journal of Mathematics

For a finite commutative ring $S$ (resp., a finite abelian group $S$) and a positive integer $k\geqslant2$, we construct an iteration digraph $G(S, k)$ whose vertex set is $S$ and for which there is a directed edge from $a\in S$ to $b\in S$ if $b=a^k$. We generalize some previous results of the iteration digraphs from the ring $\mathbb{Z}_n$ of integers modulo $n$ to finite commutative rings, and establish a necessary and sufficient condition for $G(S, k_1)$ and $G(S, k_2)$ to be isomorphic for any finite abelian group $S$.

Some Concrete Operators And Their Properties, Mehmet Gürdal, Mubariz T. Garayev, Suna Saltan

Turkish Journal of Mathematics

We consider integration and double integration operators, the Hardy operator, and multiplication and composition operators on Lebesgue space $L_{p}\left[ 0,1\right] $ and Sobolev spaces $W_{p}^{\left( n\right) }\left[ 0,1\right] $ and $W_{p}^{\left( n\right) }\left( \left[ 0,1\right] \times\left[ 0,1\right] \right) ,$ and we study their properties. In particular, we calculate norm and spectral multiplicity of the Hardy operator and some multiplication operators, investigate its extended eigenvectors, characterize some composition operators in terms of the extended eigenvectors of the Hardy operator, and calculate the numerical radius of the integration operator on the real $L_{2}\left[ 0,1\right] $ space. The main method for our investigation …