Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/11

Browse

Now showing 1 - 20 of 92

Citation - WoS: 4
Citation - Scopus: 7
Adaptive Reduced Feedback Links for Distributed Power Allocation in Multicell Miso-Ofdma Networks
(IEEE Computer Society, 2014-04) Özbek, Berna; Le Ruyet, Didier; Pischella, Mylene; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
For multi-antenna Orthogonal Frequency-Division Multiple Access (OFDMA) based multicell networks, the channel state information (CSI) of all users is required to share among base stations in order to perform distributed power allocation. However, the amount of feedback increases with the number of users, base stations, subcarriers and antennas. Therefore, it is important to perform a selection at the user side to reduce the feedback load and the complexity of resource allocation. In this letter, we propose adaptive reduced feedback links by choosing the users based on their approximate signal to interference noise ratio (SINR) and their locations in the cell to satisfy users' rate constraints. We illustrate the performance results of reduced feedback links by employing distributed resource allocation with link adaptation.
Citation - WoS: 19
Citation - Scopus: 22
Adaptive Sign Algorithm for Graph Signal Processing
(Elsevier, 2022-06) Yan, Yi; Kuruoğlu, Ercan Engin; Altınkaya, Mustafa Aziz; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Efficient and robust online processing techniques for irregularly structured data are crucial in the current era of data abundance. In this paper, we propose a graph/network version of the classical adaptive Sign algorithm for online graph signal estimation under impulsive noise. The recently introduced graph adaptive least mean squares algorithm is unstable under non-Gaussian impulsive noise and has high computational complexity. The Graph-Sign algorithm proposed in this work is based on the minimum dispersion criterion and therefore impulsive noise does not hinder its estimation quality. Unlike the recently proposed graph adaptive least mean pth power algorithm, our Graph-Sign algorithm can operate without prior knowledge of the noise distribution. The proposed Graph-Sign algorithm has a faster run time because of its low computational complexity compared to the existing adaptive graph signal processing algorithms. Experimenting on steady-state and time-varying graph signals estimation utilizing spectral properties of bandlimitedness and sampling, the Graph-Sign algorithm demonstrates fast, stable, and robust graph signal estimation performance under impulsive noise modeled by alpha stable, Cauchy, Student's t, or Laplace distributions.
Citation - WoS: 7
Citation - Scopus: 8
An All-Optical Switching Based on Resonance Breaking With a Transient Grating
(Institute of Electrical and Electronics Engineers Inc., 2010) Akın, Osman; Dinleyici, Mehmet Salih; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
A new resonance breaking in-fiber switch as an all-optical network component is investigated and presented. A transient grating is applied to break the transverse resonance of the fundamental waveguide mode and the power coupled into the higher order propagating mode is computed using coupled mode theory (CMT). The coupling of the modes with the grating forming beams in the evanescent region of the waveguide is investigated with four wave mixing (FWM). High conversion efficiency is calculated in the case of perfect phase matching at communication wavelength 1550 nm. The conversion efficiency of the proposed structure is considered in terms of third-order nonlinear susceptibility, and the effect of design and tuning parameters are investigated for grating forming geometry and laser beam intensity, respectively.
Citation - WoS: 94
Analysis and Suppression of Nonlinear Frequency Modulation in an Optical Frequency-Domain Reflectometer
(The Optical Society, 2009-03) Yüksel, Kıvılcım; Wuilpart, Marc; Mégret, Patrice; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
A new method for monitoring the nonlinearities perturbing the optical frequency sweep in high speed tunable laser sources is presented. The swept-frequency monitoring system comprises a Mach-Zehnder interferometer and simple signal processing steps. It has been implemented in a coherent optical frequency domain reflectometer which allowed to drastically reduce the effects of nonlinear sweep, resulting to a spatial resolution enhancement of 30 times. © 2009 Optical Society of America.
Citation - WoS: 2
Citation - Scopus: 2
Analytical Improvement on the Electromagnetic Scattering From Deformed Spherical Conducting Objects
(Institute of Electrical and Electronics Engineers, 2021) Ateş, Barış; Kuştepeli, Alp; Çetin, Zebih; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
In this paper, electromagnetic scattering from con-ducting deformed spheres is considered analytically by employing the perturbation method and utilizing Debye potentials. To be able to analyze a wide variety of scattering problems, azimuthal variation is indispensable and therefore the geometries of the scatterers considered in this study do not have rotational symmetry, hence they are dependent on the θ and φ angles in spherical coordinates. Analyses are carried up to the second order explicitly to obtain more accurate results and thus scattered fields are obtained with second order corrections. The coefficients used to determine the scattered field are expressed in terms of Clebsch-Gordan coefficients, which enables one to obtain the results for new geometries only by simple algebraic manipulations. Numerical results and their comparisons are also presented for various deformation functions and parameters. IEEE
Citation - WoS: 14
Citation - Scopus: 15
Analytical Investigation of a Novel Interrogation Approach of Fiber Bragg Grating Sensors Using Optical Frequency Domain Reflectometry
(Elsevier Ltd., 2016-06) Yüksel, Kıvılcım; Pala, Deniz; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
This work presents a novel approach in interrogating Polarization Dependent Loss (PDL) of cascaded identical FBGs using Optical Frequency Domain Reflectometer (OFDR). The fundamentals of both polarisation properties of uniform FBGs and polarisation-sensitive OFDR are explained and the benefits of this novel approach in measuring transversal load are discussed. The numerical programs computing the spectral evolution of PDL of the FBGs in the array as a function of grating parameters (grating length and birefringence) are presented. Our simulation results show an excellent agreement with the previously reported simulation (and experimental) results in the literature obtained on a single FBG by using classical state-of-the-art measurement techniques. As an envisaged application, the proposed system shows the feasibility of measuring the residual stresses during manufacturing process of composite materials which is not straightforward by amplitude spectrum measurements and/or considering only the axial strains. © 2016 Elsevier Ltd. All rights reserved.
Citation - WoS: 4
Citation - Scopus: 5
An Asymptotically Stable Robust Controller Formulation for a Class of Mimo Nonlinear Systems With Uncertain Dynamics
(Taylor and Francis Ltd., 2016-09) Bıdıklı, Barış; Tatlıcıoğlu, Enver; Zergeroğlu, Erkan; Bayrak, Alper; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
In this work, we present a novel continuous robust controller for a class of multi-input/multi-output nonlinear systems that contains unstructured uncertainties in their drift vectors and input matrices. The proposed controller compensates uncertainties in the system dynamics and achieves asymptotic tracking while requiring only the knowledge of the sign of the leading principal minors of the input gain matrix. A Lyapunov-based argument backed up with an integral inequality is applied to prove the asymptotic stability of the closed-loop system. Simulation results are presented to illustrate the viability of the proposed method.
Citation - WoS: 7
Citation - Scopus: 9
Automatic Identification of Highly Conserved Family Regions and Relationships in Genome Wide Datasets Including Remote Protein Sequences
(Public Library of Science, 2013-09) Doğan, Tunca; Karaçalı, Bilge; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Identifying shared sequence segments along amino acid sequences generally requires a collection of closely related proteins, most often curated manually from the sequence datasets to suit the purpose at hand. Currently developed statistical methods are strained, however, when the collection contains remote sequences with poor alignment to the rest, or sequences containing multiple domains. In this paper, we propose a completely unsupervised and automated method to identify the shared sequence segments observed in a diverse collection of protein sequences including those present in a smaller fraction of the sequences in the collection, using a combination of sequence alignment, residue conservation scoring and graph-theoretical approaches. Since shared sequence fragments often imply conserved functional or structural attributes, the method produces a table of associations between the sequences and the identified conserved regions that can reveal previously unknown protein families as well as new members to existing ones. We evaluated the biological relevance of the method by clustering the proteins in gold standard datasets and assessing the clustering performance in comparison with previous methods from the literature. We have then applied the proposed method to a genome wide dataset of 17793 human proteins and generated a global association map to each of the 4753 identified conserved regions. Investigations on the major conserved regions revealed that they corresponded strongly to annotated structural domains. This suggests that the method can be useful in predicting novel domains on protein sequences.
Citation - WoS: 25
Citation - Scopus: 38
An Automatic Pitch Analysis Method for Turkish Maqam Music
(Taylor and Francis Ltd., 2008-03) Bozkurt, Barış; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Automatic pitch analysis of large audio databases is essential for studies on music information retrieval and developing a pitch scale theory for Turkish maqam music. However no such study is available. In this article, we first determine the main obstacle as the alignment of frequency analysis results from multiple files. We then propose a new method to automatically detect the tonic of a recording, align the data, and estimate overall frequency histograms from large databases. We show that such histograms can be successfully used for pitch scale (tuning) studies on the recordings of Tanburi Cemil Bey, an undisputed master of the genre
Citation - WoS: 11
Citation - Scopus: 10
Bayesian Volterra System Identification Using Reversible Jump Mcmc Algorithm
(Elsevier Ltd., 2017-12) Karakuş, Oktay; Kuruoğlu, Ercan Engin; Altınkaya, Mustafa Aziz; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Volterra systems have had significant success in modelling nonlinear systems in various real-world applications. However, it is generally assumed that the nonlinearity degree of the system is known beforehand. In this paper, we contribute to the literature on Volterra system identification (VSI) with a numerical Bayesian approach which identifies model coefficients and the nonlinearity degree concurrently. Although this numerical Bayesian method, namely reversible jump Markov chain Monte Carlo (RJMCMC) algorithm has been used with success in various model selection problems, our use is in a novel context in the sense that both memory size and nonlinearity degree are estimated. The aforementioned study ensures an anomalous approach to RJMCMC and provides a new understanding on its flexible use which enables trans-structural transitions between different classes of models in addition to transdimensional transitions for which it is classically used. We study the performance of the method on synthetically generated data including OFDM communications over a nonlinear channel.
Citation - WoS: 4
Citation - Scopus: 5
Beyond Trans-Dimensional Rjmcmc With a Case Study in Impulsive Data Modeling
(Elsevier Ltd., 2018-12) Karakuş, Oktay; Kuruoğlu, Ercan Engin; Altınkaya, Mustafa Aziz; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Reversible jump Markov chain Monte Carlo (RJMCMC) is a Bayesian model estimation method, which has been generally used for trans-dimensional sampling and model order selection studies in the literature. In this study, we draw attention to unexplored potentials of RJMCMC beyond trans-dimensional sampling. the proposed usage, which we call trans-space RJMCMC exploits the original formulation to explore spaces of different classes or structures. This provides flexibility in using different types of candidate classes in the combined model space such as spaces of linear and nonlinear models or of various distribution families. As an application, we looked into a special case of trans-space sampling, namely trans-distributional RJMCMC in impulsive data modeling. In many areas such as seismology, radar, image, using Gaussian models is a common practice due to analytical ease. However, many noise processes do not follow a Gaussian character and generally exhibit events too impulsive to be successfully described by the Gaussian model. We test the proposed usage of RJMCMC to choose between various impulsive distribution families to model both synthetically generated noise processes and real-life measurements on power line communications impulsive noises and 2-D discrete wavelet transform coefficients.
Citation - WoS: 8
Citation - Scopus: 9
Calculation of the Wavelength Filter Properties of the Fiber-Slab Waveguide Structure Using Vector Mode Expansion
(Institute of Electrical and Electronics Engineers Inc., 1998-11) Dinleyici, Mehmet Salih; Patterson, David B.; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
A vectorial solution technique is applied to investigate the dispersion characteristics of the ridge modes of a waveguide structure comprising a slab and optical fiber. The power transmission characteristics of the device with respect to wavelength are calculated under various device parameters, such as slab index and fiber-slab separation. We discuss the effects of such parameters on the bandwidth and rejection of the notch filter produced by this structure.
Citation - WoS: 5
Citation - Scopus: 5
The Circuit Realization of Mexican Hat Wavelet Function
(Urban und Fischer Verlag GmbH und Co. KG, 2005-09) Özkurt, Nalan; Savacı, Ferit Acar; Gündüzalp, Mustafa; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
A wavelet network circuit implementation for Mexican Hat mother wavelet has been proposed for nonlinear function approximation which can also be used for the realization of the algebraic nonlinear components. The Mexican Hat mother wavelet function has been implemented with discrete circuit components and it has been observed that the experimental waveform obtained from the realized circuit is approximately same as the Spice simulation of the original function. The circuit simulations of exemplar functions implemented in Spice are also given. © 2004 Elsevier GmbH. All rights reserved.
Citation - WoS: 54
Citation - Scopus: 54
Cmos Enabled Microfluidic Systems for Healthcare Based Applications
(John Wiley and Sons Inc., 2018-04) Hussian, Muhammad M.; Khan, Sherjeel M.; Gümüş, Abdurrahman; Nassar, Joanna M.; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
With the increased global population, it is more important than ever to expand accessibility to affordable personalized healthcare. In this context, a seamless integration of microfluidic technology for bioanalysis and drug delivery and complementary metal oxide semiconductor (CMOS) technology enabled data-management circuitry is critical. Therefore, here, the fundamentals, integration aspects, and applications of CMOS-enabled microfluidic systems for affordable personalized healthcare systems are presented. Critical components, like sensors, actuators, and their fabrication and packaging, are discussed and reviewed in detail. With the emergence of the Internet-of-Things and the upcoming Internet-of-Everything for a people–process–data–device connected world, now is the time to take CMOS-enabled microfluidics technology to as many people as possible. There is enormous potential for microfluidic technologies in affordable healthcare for everyone, and CMOS technology will play a major role in making that happen.
Citation - WoS: 234
Citation - Scopus: 255
A Community Computational Challenge To Predict the Activity of Pairs of Compounds
(Nature Publishing Group, 2014-12) Bansal, Mukesh; Yang, Jichen; Karan, Charles; Menden, Michael P.; Costello, James C.; Tang, Hao; Xiao, Guanghua; Li, Yajuan; Allen, Jeffrey; Zhong, Rui; Chen, Beibei; Kim, Minsoo; Wang, Tao; Heiser, Laura M.; Realubit, Ronald; Mattioli, Michela; Alvarez, Mariano J.; Shen, Yao; NCI-DREAM Community; Karaçalı, Bilge; Gallahan, Daniel; Singer, Dinah; Saez-Rodriguez, Julio; Xie, Yang; Stolovitzky, Gustavo; Califano, Andrea; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Recent therapeutic successes have renewed interest in drug combinations, but experimental screening approaches are costly and often identify only small numbers of synergistic combinations. The DREAM consortium launched an open challenge to foster the development of in silico methods to computationally rank 91 compound pairs, from the most synergistic to the most antagonistic, based on gene-expression profiles of human B cells treated with individual compounds at multiple time points and concentrations. Using scoring metrics based on experimental dose-response curves, we assessed 32 methods (31 community-generated approaches and SynGen), four of which performed significantly better than random guessing. We highlight similarities between the methods. Although the accuracy of predictions was not optimal, we find that computational prediction of compound-pair activity is possible, and that community challenges can be useful to advance the field of in silico compound-synergy prediction.
Citation - WoS: 546
Citation - Scopus: 594
A Community Effort To Assess and Improve Drug Sensitivity Prediction Algorithms
(Nature Publishing Group, 2014-12) Costello, James C.; Heiser, Laura M.; Georgii, Elisabeth; Gönen, Mehmet; Menden, Michael P.; Wang, Nicholas J.; Bansal, Mukesh; Ammad-ud-din, Muhammad; Hintsanen, Petteri; Khan, Suleiman A.; Mpindi, John-Patrick; Kallioniemi, Olli; Honkela, Antti; Aittokallio, Tero; Wennerberg, Krister; NCI-DREAM Community; Karaçalı, Bilge; Collins, James J.; Gallahan, Dan; Singer, Dinah; Saez-Rodriguez, Julio; Kaski, Samuel; Gray, Joe W.; Stolovitzky, Gustavo; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Predicting the best treatment strategy from genomic information is a core goal of precision medicine. Here we focus on predicting drug response based on a cohort of genomic, epigenomic and proteomic profiling data sets measured in human breast cancer cell lines. Through a collaborative effort between the National Cancer Institute (NCI) and the Dialogue on Reverse Engineering Assessment and Methods (DREAM) project, we analyzed a total of 44 drug sensitivity prediction algorithms. The top-performing approaches modeled nonlinear relationships and incorporated biological pathway information. We found that gene expression microarrays consistently provided the best predictive power of the individual profiling data sets; however, performance was increased by including multiple, independent data sets. We discuss the innovations underlying the top-performing methodology, Bayesian multitask MKL, and we provide detailed descriptions of all methods. This study establishes benchmarks for drug sensitivity prediction and identifies approaches that can be leveraged for the development of new methods.
Citation - WoS: 85
Citation - Scopus: 100
A Comparative Study of Glottal Source Estimation Techniques
(Elsevier Ltd., 2012-01) Drugman, Thomas; Bozkurt, Barış; Dutoit, Thierry; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Abstract: Source-tract decomposition (or glottal flow estimation) is one of the basic problems of speech processing. For this, several techniques have been proposed in the literature. However, studies comparing different approaches are almost nonexistent. Besides, experiments have been systematically performed either on synthetic speech or on sustained vowels. In this study we compare three of the main representative state-of-the-art methods of glottal flow estimation: closed-phase inverse filtering, iterative and adaptive inverse filtering, and mixed-phase decomposition. These techniques are first submitted to an objective assessment test on synthetic speech signals. Their sensitivity to various factors affecting the estimation quality, as well as their robustness to noise are studied. In a second experiment, their ability to label voice quality (tensed, modal, soft) is studied on a large corpus of real connected speech. It is shown that changes of voice quality are reflected by significant modifications in glottal feature distributions. Techniques based on the mixed-phase decomposition and on a closed-phase inverse filtering process turn out to give the best results on both clean synthetic and real speech signals. On the other hand, iterative and adaptive inverse filtering is recommended in noisy environments for its high robustness. © 2011 Elsevier Ltd. All rights reserved.
Citation - WoS: 14
Citation - Scopus: 15
Compensating of Added Mass Terms in Dynamically Positioned Surface Vehicles: a Continuous Robust Control Approach
(Elsevier Ltd., 2017) Bıdıklı, Barış; Tatlıcıoğlu, Enver; Zergeroğlu, Erkan; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
In this work, we provide a tracking controller formulation for dynamically positioned surface vessels with an asymmetric added mass terms that affects the overall system dynamics at the acceleration level. Specifically a novel continuous robust controller is proposed for surface vessels that in addition to unstructured uncertainties in its dynamics, contains added mass effects in its inertia matrix. The proposed controller compensates the overall system uncertainties while ensuring asymptotic tracking by utilizing the knowledge of the leading principal minors of the input gain matrix. Stability of the closed–loop system and asymptotic convergence are proven via Lyapunov based approaches. Simulation studies are also presented to illustrate the viability of the proposed method
Citation - WoS: 35
Complete Analysis of Multireflection and Spectral-Shadowing Crosstalks in a Quasi-Distributed Fiber Sensor Interrogated by Ofdr
(Institute of Electrical and Electronics Engineers Inc., 2012) Yüksel, Kıvılcım; Moeyaert, Véronique; Mégret, Patrice; Wuilpart, Marc; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
We present the analysis of a quasi-distributed fiber sensor based on the concatenation of identical low-reflective fiber Bragg gratings (FBGs) taking into account both multireflection and spectral-shadowing crosstalks. This allows obtaining more realistic values of the design parameters such as the maximum number of sensing points, the reflectivity of the gratings, and the distance between the sensing points. © 2001-2012 IEEE.
Citation - WoS: 21
Citation - Scopus: 26
Computerized Method for Nonrigid Mr-To Breast-Image Registration
(Elsevier Ltd., 2010-01) Ünlü, Mehmet Zübeyir; Krol, A.; Magri, A.; Mandel, J. A.; Lee, W.; Baum, K. G.; Lipson, E. D.; Coman, I. L.; Feiglin, D. H.; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
We have developed and tested a new simple computerized finite element method (FEM) approach to MR-to-PET nonrigid breast-image registration. The method requires five-nine fiducial skin markers (FSMs) visible in MRI and PET that need to be located in the same spots on the breast and two on the flanks during both scans. Patients need to be similarly positioned prone during MRI and PET scans. This is accomplished by means of a low gamma-ray attenuation breast coil replica used as the breast support during the PET scan. We demonstrate that, under such conditions, the observed FSM displacement vectors between MR and PET images, distributed piecewise linearly over the breast volume, produce a deformed FEM mesh that reasonably approximates nonrigid deformation of the breast tissue between the MRI and PET scans. This method, which does not require a biomechanical breast tissue model, is robust and fast. Contrary to other approaches utilizing voxel intensity-based similarity measures or surface matching, our method works for matching MR with pure molecular images (i.e. PET or SPECT only). Our method does not require a good initialization and would not be trapped by local minima during registration process. All processing including FSMs detection and matching, and mesh generation can be fully automated. We tested our method on MR and PET breast images acquired for 15 subjects. The procedure yielded good quality images with an average target registration error below 4 mm (i.e. well below PET spatial resolution of 6-7 mm). Based on the results obtained for 15 subjects studied to date, we conclude that this is a very fast and a well-performing method for MR-to-PET breast-image nonrigid registration. Therefore, it is a promising approach in clinical practice. This method can be easily applied to nonrigid registration of MRI or CT of any type of soft-tissue images to their molecular counterparts such as obtained using PET and SPECT. © 2009 Elsevier Ltd. All rights reserved.

Browse

Browsing Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği by Scopus Q "Q1"