Engineering Commons^™

Iterative Sensitivity Matrix-Based Magnetic Resonance Conductivity Tensor Imaging, Evren Deği̇rmenci̇

Turkish Journal of Electrical Engineering and Computer Sciences

Magnetic resonance conductivity tensor imaging (MRCTI) reconstructs high-resolution anisotropic conductivity images, which are proved to have critical importance in radio-oncological imaging as well as source localization fields. In the MRCTI technique, linearly independent current injections are applied to the region to be imaged and resulting magnetic flux densities are measured using magnetic resonance imaging techniques. In this study, a novel iterative reconstruction algorithm based on a sensitivity matrix approach is proposed and tested using both simulated and experimental measurements. Obtained results show that the proposed technique can reconstruct anisotropic conductivity images with high and position-independent spatial resolution in addition to …

A Compact Wide-Slot Uwb Antennawith Reconfigurable And Sharp Dual-Band Notches For Underlay Cognitive Radioapplications, Falih Alnahwi, Abdulghafor Abdulhameed, Husham Swadi, Abdulkareem Abdullah

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a compact wide-slot ultrawide-band (UWB) antenna with reconfigurable and sharp dual-band notches compatible with the underlay cognitive radio systems. The antenna slot and tuning stub are reshaped in such a way that the proposed antenna operating bandwidth extends along the frequency band specified for UWB applications (3.1-10.6 GHz). In spite of their sharpness, the generated band notches perfectly cancel the interference with the entire 5 GHz wireless local area network (WLAN) frequency band (5.15-5.725 GHz) and that of the military X-band satellite communications downlink (7.25-7.745 GHz). The WLAN band notch is presented by attaching a pair of …

A Novel And Unified Approach For Averaged Channel Capacity And Averagedeffective Capacity Analyses Of Diversity Combining And Multihop Transmissionschemes In Flat Fading Environments, Ferkan Yilmaz, Mohamed-Slim Alouini

Turkish Journal of Electrical Engineering and Computer Sciences

n this paper, we introduce an Lp -norm aggregation to present a signal-to-noise ratio expression unified not only for such diversity combining schemes as equal-gain combining, maximal-ratio combining, and selection combining, but also for such transmission techniques as multihop transmission. Accordingly, we propose two moment-generating function-based approaches that both respectively unify the exact analyses of the averaged channel capacity and averaged effective capacity over generalized fading channels with respect to the diversity combining and multihop transmission schemes. Finally, the mathematical formalism is illustrated by numerical special cases and verified by simulations.

Pipelined Adders For Ultralow-Power Wearables, Mansi Jhamb, Tejaswini Dhall, Tamish Verma, Hinduja Puri

Turkish Journal of Electrical Engineering and Computer Sciences

For continuous real-time monitoring of personal health, wearable devices are indispensable. The constraintsof cost, power consumption, and limited device dimensions are the critical issues which need to be handled carefullywhile designing these battery-powered devices. The wearables employ high-end processors dedicated for complex signalprocessing. The core of every digital signal processor is its data path. The arithmetic units like adders constitute thecore of data path and addressing unit. This work proposes a novel low-complexity asynchronous pipelined adder. Theproposed design guarantees great savings in power and latency, which makes it a suitable candidate for low-power high-speed sophisticated wearables. The proposed design consumes …

Contribution Of Artificial Proprioception On A Dynamic Finger Flexion Task, Mehdi Hojatmadani, Evren Samur

Turkish Journal of Electrical Engineering and Computer Sciences

There has been a considerable effort to provide sensory feedback for myoelectric prostheses. Among the solutions provided in the literature, sensory substitution is an easy and cost-effective way to provide feedback through different sensory modalities at different locations on the body. In this study, we evaluate the effect of sensory substitution of force and position feedback on a two-degree-of-freedom dynamic finger flexion task. For this purpose, a new methodology and an experimental setup are developed. The experimental methodology is based on the "strength-dexterity test", working on the principle of buckling of compression springs. The experimental setup comprises a haptic interface, …

Power Electronic Controller With Time Sharing Switching Strategy For Grid Connected Pv Systems, Maria Jenisha Charles, Ammasaigounden Nanjappagounder, Binu Ben Jose Dharmaian Retnam

Turkish Journal of Electrical Engineering and Computer Sciences

The design and implementation of a high-efficiency two-stage power electronic controller for feeding power from a photovoltaic (PV) array to the load/utility grid is proposed. The PV array is connected to the load/utility grid through a boost converter and an inverter. The boost converter is controlled by sinusoidal pulse width modulation (SPWM) pulses so as to get a clamped quasi-sinusoidal waveform at the DC link. The inverter converts the clamped quasi-DC voltage into AC voltage using the SPWM controller. At any time only one switch operates at high frequency, thus yielding reduction in the switching losses of the converters. The …

Heuristic Optimization Techniques For Voltage Stability Enhancement Of Radial Distribution Network With Simultaneous Consideration Of Network Reconfiguration And Dg Sizing And Allocations, Mahiraj Singh Rawat, Shelly Vadhera

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, heuristic optimization techniques, such as integrated particle swarm optimization (IPSO), teaching--learning-based optimization (TLBO), and Jaya optimization, were applied effectively for the first time to optimize the radial distribution network (RDN) by simultaneously considering reconfiguration of the network and allocation and sizing of the distributed generations (DG). The objectives were to maximize the voltage stability and to minimize the power loss of the network without violating the system constraints. In standard PSO technique, the movement of current particle depends upon global best position and its own best position up to current step. However, if the particle lies too …

Convex Polygon Triangulation Based On Planted Trivalent Binary Tree\\ And Ballot Problem, Muzafer Saracevic, Aybeyan Seli̇mi̇

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a new technique of generation of convex polygon triangulation based on planted trivalent binary tree and ballot notation. The properties of the Catalan numbers were examined and their decomposition and application in developing the hierarchy and triangulation trees were analyzed. The method of storage and processing of triangulation was constructed on the basis of movements through the polygon. This method was derived from vertices and leaves of the planted trivalent binary tree. The research subject of the paper is analysis and comparison of a constructed method for solving of convex polygon triangulation problem with other methods and …

Improving Anomaly Detection In Bgp Time-Series Data By New Guide Features And Moderated Feature Selection Algorithm, Mahmoud Hashem, Ahmed Bashandy, Samir Shaheen

Turkish Journal of Electrical Engineering and Computer Sciences

The Internet infrastructure relies on the Border Gateway Protocol (BGP) to provide essential routing information where abnormal routing behavior impairs global Internet connectivity and stability. Hence, employing anomaly detection algorithms is important for improving the performance of BGP routing protocol. In this paper, we propose two algorithms; the first is the guide feature generator (GFG), which generates guide features from traditional features in BGP time-series data using moving regression in combination with smoothed moving average. The second is a modified random forest feature selection algorithm which is employed to automatically select the most dominant features (ASMDF). Our mechanism shows that …

Detection Of Hemorrhage In Retinal Images Using Linear Classifiers And Iterative Thresholding Approaches Based On Firefly And Particle Swarm Optimization Algorithms, Kemal Adem, Mahmut Heki̇m, Seli̇m Demi̇r

Turkish Journal of Electrical Engineering and Computer Sciences

We propose a novel iterative thresholding approach based on firefly and particle swarm optimization to be used for the detection of hemorrhages, one of the signs of diabetic retinopathy disease. This approach consists of the enhancement of the image using basic preprocessing methods, the segmentation of vessels with the help of Gabor and Top-hat transformation for the removal of the vessels from the image, the determination of the number of regions with hemorrhages and pixel counts in these regions using firefly algorithm (FFA) and particle swarm optimization algorithm (PSOA)-based iterative thresholding, and the detection of hemorrhages with the help of …

Accurate And Compact Stochastic Computations By Exploiting Correlation, Hamdan Abdellatef, Mohamed Khalil Hani, Nasir Shaikh-Husin

Turkish Journal of Electrical Engineering and Computer Sciences

Recent studies have shown, contrary to what was previously believed, that by exploiting correlation in stochastic computing (SC) designs, more accurate SC circuits with low area cost can be realized. However, if these basic SC circuits or blocks are cascaded in series to form a large complex system, correlation between stochastic numbers (SNs) from one block to the next would be lost; thus, inaccuracies are introduced. In this study, we propose correlating circuits to be used in building complex correlated SC systems. One of the circuits is the correlator that restores lost correlations between two SNs due to previous processing. …

A Multiseed-Based Svm Classification Technique For Training Sample Reduction, Imran Sharif, Debasis Chaudhuri

Turkish Journal of Electrical Engineering and Computer Sciences

A support vector machine (SVM) is not a popular method for a very large dataset classification because the training and testing time for such data are computationally expensive. Many researchers try to reduce the training time of SVMs by applying sample reduction methods. Many methods reduced the training samples by using a clustering technique. To reduce its high computational complexity, several data reduction methods were proposed in previous studies. However, such methods are not effective to extract informative patterns. This paper demonstrates a new supervised classification method, multiseed-based SVM (MSB-SVM), which is particularly intended to deal with very large datasets …

Boltzmann Analysis Of Electron Swarm Parameters In Chf3+Cf4 Mixtures, Hidir Düzkaya, Süleyman Sungur Tezcan

Turkish Journal of Electrical Engineering and Computer Sciences

The electron drift velocity, mean energy, ionization, attachment, effective ionization coefficient, limit electrical field, and synergism of pure CHF3 (fluoroform), pure CF4 (tetrafluoromethane), and CHF3+CF4 gas mixtures are calculated by Boltzmann equation analysis in a wide range of density normalized electrical fields (E/N). The finite difference method is used to solve the two-term approximation of the Boltzmann equation under steady-state Townsend conditions. To our knowledge, no previous electron swarm parameters of these mixtures have been published. At constant E/N values, the electron mean energies and drift velocities increase with decreasing CHF3 content. The addition of CF4 into the mixture increases …

Comparative Analysis Of A Novel Topology For Single-Phase Z-Source Inverter With Reduced Number Of Switches, Himanshu Sharma, Rintu Khanna, Neelu Jain

Turkish Journal of Electrical Engineering and Computer Sciences

Z-source inverter has recently been introduced to overcome the limitations of conventional voltage source inverter. This paper deals with a novel topology of single-phase Z-source inverter (ZSI). This topology reduced the number of passive elements and active switches in order to make the inverter cheaper and smaller in size compared to traditional ZSI. Detailed analysis of the proposed topology is presented in this paper which includes calculations of boost factor, total harmonic disorder, magnitude of output voltage etc. Modulation technique used to control the switching of the proposed inverter is explained in detail. This paper also compares the proposed topology …

Synchronization And Antisynchronization Protocol Design Of Chaotic Nonlinear Gyros: An Adaptive Integral Sliding Mode Approach, Fazal Ur Rahman, Qudrat Khan, Rini Akmeliawati

Turkish Journal of Electrical Engineering and Computer Sciences

A novel control protocol design, via integral sliding mode control with parameter update laws, for synchronization and desynchronization of a chaotic nonlinear gyro with unknown parameters is the focus of this work. The error dynamics of the actual system are substructured into nominal and uncertain parts to employ adaptive integral sliding mode (AISM) control. The uncertain parameters are estimated via devised adaptive laws. Then the disagreement dynamics are guided to origin via AISM control. The stabilizing controller is also designed in terms of nominal control along with a compensating component. The control and the parameter update laws are constructed to …

Oxidative Degradation Of Lignin And Investigation Of Utilization Of Lignin-Derived Materials As Building Blocks For Epoxy Resins, Zhen Fang

Theses and Dissertations--Chemistry

Lignin, the second most abundant biopolymer on earth, is potentially a replaceable source for bulky fuels and chemical feedstocks. There have been numerous reports on methods for the oxidative cleavage of β-O-4 linkages but relatively few reports of how those methods affect other linkages that are present in lignin. We investigated how the β-1 and β-5 linkages respond under oxidative conditions proposed for lignin deconstruction based on their effect on β-O-4 linkages. Mechanochemical treatment of lignin can greatly improve the yield of monomer products and we applied a mechanochemical approach, using powerful ring-and-puck milling to promote lignin degradation. Along with …

Benchmarking And Evaluating The Efficiency Of Mass Transit Systems Based On Best Practice Using Data Envelopment Analysis, Jacqueline Nayame, Maoloud Dabab, Timothy Anderson

Engineering and Technology Management Faculty Publications and Presentations

Public transit systems in the USA have been faced with mounting pressure to decrease their operating costs while at the same time expected to increase ridership and meeting multiple societal needs. The primary objective of this study is to measure the efficiencies of mass transit agencies based on best practice in the US, identify the influencing factors leading to their efficiencies, and how these strategies and policies can be used improve inefficiency in transit agencies. Using Data Envelopment Analysis (DEA) method, the study analyzed the mass performance of 334 transit agencies across the US using data from the national transit …

Youtube’S Terms Of Service: Posthumanism, Algorithms, And Professional Writing, Sarah Bresnahan

Graduate Research Theses & Dissertations

This thesis aims to examine YouTube’s Terms of Service as it applies to content creators (known as YouTubers) who use the platform as a means of financial gain and how YouTube’s demonetization policy via an algorithm is negatively affecting them. I conducted a case study featuring one creator, Michelle Guido, and attempted to determine why some of her content is demonetized when it fulfills YouTube’s content standards for monetization. This study is meant as an examination through the lens of Dr. N. Katherine Hayles’s theory of posthumanism as stated in her book, How We Became Posthuman, and will offer insight …

Direct Polymer Grafting As A Method Of Maintaining The Mechanical Properties Of Cellulose Nanocrystals In The Presence Of Moisture, Mary Elizabeth Breen-Lyles

Graduate Research Theses & Dissertations

Cellulose nanocrystals (CNCs) are a distinctive nanomaterial derived from cellulose, the most abundant natural polymer on Earth, and the primary reinforcing structural component of cellulose fibrils found within the plant cell wall. These nanocrystals exhibit mechanical properties comparable to synthetic aramid fibers but are advantageous as they are biodegradable, renewable, and can be produced sustainably as they are predominantly extracted from naturally occurring cellulosic materials. These qualities make it a sustainable, highly renewable and environmentally friendly material to be used in place of synthetic materials in a variety of applications. With their high surface area to volume ratio, low level …

Validation Of A Low-Cost Sensor For Development Of Wearable And Handheld Spectrometers, Justin Leslie Cathey

Graduate Research Theses & Dissertations

This study examined the possibility of creating a quantitative radiometric spectrometer from a low-cost relative radiometric spectrometer sensor through the use of statistical analysis and development of a correction factor (p > 0.05). Radiometric spectrometers are able to measure and fully characterize the radiometric and photometric characteristics of light, while relative spectrometers are not able to fully, quantitatively characterize the radiometric response from a light source, thus they are less expensive. The spectrometer created in this research is able to measure and produce comparative lighting parameters as well as an actual radiometer spectrometer.

The photoreceptors cells within the human eye allow …

Studying The Effect Of Vacancies On The Thermal Conductivity Of Metal-Coated Carbon Nanotubes Using Molecular Dynamics Atomistic Simulations, Ravindra Sunil Dhumal

Graduate Research Theses & Dissertations

Breakthroughs in nanotechnology have made it possible for the size of electronic gadgets to be scaled down to micro/nano level. What follows however, is the side effect of high power densities and overheating as the heat dissipation is restricted to very small surface area. Thus, the need of an effective thermal management system is central to these developments. One way to counter this problem is to use Thermal Interface Materials (TIMs) which promote heat transfer between heat source and sink.

Owing to their high thermal conductivity (up to 6000 W/mK), Carbon Nanotubes (CNTs) are thought of as strong candidates for …

Steady Flows In Annular Wedge Lid-Driven Cavities, Anandan Ganapathy

Graduate Research Theses & Dissertations

The lid-driven cavity is a well-known canonical problem in the field of analytical and computational fluid dynamics. It is comprised of a square domain of an incompressible fluid with its upper lid has a specified velocity and the remaining wall boundaries are subjected to fixed, no-slip, zero-velocity constraints. There are numerous examples found in the literature that address the well-known, stable behavior of this system, which includes a primary recirculating vortex, secondary corner vortices, and a velocity profile through the center midpoint y-axis that is shown to be dependent on the Reynolds number. In this investigation, the shape of the …

Proper Orthogonal Decomposition Analysis Of Lid-Driven Cavity Flows Containing Particle Suspensions., Nitin Katiki

Graduate Research Theses & Dissertations

Previous experiments done on the square lid driven cavity have shown that its stability and transitional behavior, and by extension the behavior of more complex flows, can be greatly modified by introducing systematic disturbances called perturbations to its flow field. In this study, a square lid driven cavity is calculated in two-dimensional space and perturbed by means of particles suspended in the flow. The perturbations manifest as subtle changes in the flow field velocity and overall flow structure, these are caused by the particle-fluid drag interaction and the particle-particle collision interaction. To understand the nature of these changes and their …

Temporal Dynamics Of Human Emotional Response To Aversive Stimuli, Joseph Lawence Kempel

Graduate Research Theses & Dissertations

Emotions are an integral part of human expression and are often communicated nonverbally through behavioral actions. With advancements in electroencephalography (EEG) technology it is now possible to measure the dynamics of emotion generation in an individual on the basis of patterns in their brain activity. This thesis aims to model the temporal dynamics of human emotion generation upon exposure to aversive stimuli and measure the effect of external distractions as a viable emotion regulation strategy.

This research builds on previous work in the literature that has shown that the ability of humans to regulate their emotions intrinsically (based on their …

The Treatment Of Contaminated Water Using Electrocoagulation, Adebayo Edward Adejinle

Graduate Research Theses & Dissertations

Wastewater treatment is a process that is used to remove significant amount of contaminant concentration from wastewater, which prevents harm to the environment. Chemical coagulation (CC) is one of the most influential processes used to remove contaminants, and it is the addition of chemicals called coagulants, which causes particles to stick together forming bigger flocs. However, as effective as CC is, it requires bench scale testing for determining the appropriate dosing rate for specific raw water properties, which makes the process time consuming. To eliminate these issues, the introduction of the Electrocoagulation (EC) process is considered. The EC process is …

Sky Surveys Scheduling Using Reinforcement Learning, Andres Felipe Alba Hernandez

Graduate Research Theses & Dissertations

Modern cosmic sky surveys (e.g., CMB S4, DES, LSST) collect a complex diversity of astronomical objects. Each of class of objects presents different requirements for observation time and sensitivity. For determining the best sequence of exposures for mapping the sky systematically, conventional scheduling methods do not optimize the use of survey time and resources. Dynamic sky survey scheduling is an NP-hard problem that has been therefore treated primarily with heuristic methods. We present an alternative scheduling method based on reinforcement learning (RL) that aims to optimize the use of telescope resources for scheduling sky surveys.

We present an exploration of …

Studies On Semiconductor Gas Sensors Using Nanostructure Growth Employing Ortho-Glancing Angle Deposition, Dean R. Walters

Graduate Research Theses & Dissertations

A program of research was undertaken to develop the next generation of metal oxide gas sensors, which, for the purpose of this research, were made from materials using a unique approach of glancing angle deposition (GLAD) that is scalable to large scale production. This research seeks to demonstrate that high-sensitivity sensors can be produced. The sensors were examined in a test system of novel design in which the units underwent performance measurements using analyte gases, such as carbon dioxide, nitrogen, and water.

Gas sensors can be improved by increasing the surface area of the active sensing media, and in this …

Knot Optimization For Univariate Cubic L^1 Spline Fits With Application In Change Point Detection, Manfei Xie

Graduate Research Theses & Dissertations

Cubic $L^1$ spline fits, as a type of $L^1$ approximating splines, have shown superior performance in shape preservation of geometric data with great changes. To better construct a cubic $L^1$ spline fit, the number and the location of the spline knots should be optimized rather than predetermined. This research investigates knot optimization methods for univariate cubic $L^1$ spline fits. When the number of knots is given, we design an optimization-based method to determine the best location of the knots. When the number and the location are unknown, we propose a heuristic method to find proper knot number and location. Numerical …

Implementation Of The Shpb System For Material Property Test Under High Strain Rate Deformation, Jiaqi Zhu

Graduate Research Theses & Dissertations

Since Bertram Hopkinson first raised the concept of Hopkinson pressure bar in 1914, many efforts have been taken by engineers and scholars for developing the system to measure the stress pulse propagation in metal bars for studying the properties of different materials under high strain rate deformation. The Northern Illinois University Material’s Lab has also built two generations of the split Hopkinson pressure bar (SHPB) system with the effort of several senior design teams in history.

The aim of this study is to develop the existing SHPB system of NIU to make it function properly. By redesigning the gun barrel, …

Thermal Analysis And Design Of Conduction Links For A Superconducting Radio Frequency Resonator, Aaron Mckeown

Graduate Research Theses & Dissertations

The SRF conduction link project at Fermi National Accelerator Laboratory aims to develop an SRF particle accelerator design that is more applicable for industrial use. Collaboration between NIU college of engineering and NIU department of physics provided the bulk of design and analysis for this project. Currently, cooling systems, used in SRF particle accelerators, pump liquid helium across the SRF cavity to provide convection based cooling. The goal of this project is to incorporate a conduction based cooling system. In a conduction based cooling system, heat will flow from the SRF cavity into a cryocooler through a conduction link. In …