Yazar "Gerek, Ömer Nezih" için Makale Koleksiyonu listeleme
-
2-D analysis and compression of power-quality event data
Gerek, Ömer Nezih; Ece, Dugan Gökhan (IEEE-Inst Electrical Electronics Engineers Inc, 2004)This paper introduces a novel two-dimensional (2-D) representation of the power quality event data. 2-D discrete-time wavelet transform is applied to the 2-D representation of real-life event data. The proposed representation ... -
A 2-D orientation-adaptive prediction filter in lifting structures for image coding
Gerek, Ömer Nezih; Çetin, A. E. (2006)Lifting-style implementations of wavelets are widely used in image coders. A two-dimensional (2-D) edge adaptive lifting structure, which is similar to Daubechies 5/3 wavelet, is presented. The 2-D prediction filter predicts ... -
Adaptive polyphase subband decomposition structures for image compression
Gerek, Ömer Nezih; Çetin, AE (IEEE-Inst Electrical Electronics Engineers Inc, 2000)Subband decomposition techniques have been extensively used for data coding and analysis. In most filter banks, the goal is to obtain subsampled signals corresponding to different spectral regions of the original data. ... -
An adaptive statistical method for power quality analysis
Gerek, Ömer Nezih; Ece, Dugan Gökhan (IEEE-Inst Electrical Electronics Engineers Inc, 2005)Digital fault recorders installed for monitoring current and/or voltage waveforms acquire and store vast amount of waveform data for post processing. Because of this, effective offline automated event detection from acquired ... -
Automatic recognition of scenes with power line wires in real life aerial images using DCT-based features
Yetgin, Ömer Emre; Gerek, Ömer Nezih (Academic Press Inc Elsevier Science, 2018)This paper presents results of power line scene detection methods that use new feature extraction/selection strategies based on Discrete Cosine Transform (DCT) of scenes obtained from aircraft-based cameras. Whenever a ... -
Circular Uncertainty method for range-only localization with imprecise sensor positions
Uluskan, Seçkin; Filik, Tansu; Gerek, Ömer Nezih (Springer, 2018)This study provides an effective new method to solve the range-only localization in the presence of sensor position errors. In practice, the sensors can stay only within a limited region whereas the target can be far from ... -
Classifier-based offline feature selection and evaluation for visual tracking of sea-surface and aerial targets
Çakır, Serdar; Aytaç, Tayfun; Yıldırım, Alper; Gerek, Ömer Nezih (Spie-Soc Photo-Optical Instrumentation Engineers, 2011)An offline feature selection and evaluation mechanism is used in order to develop a robust visual tracking scheme for sea-surface and aerial targets. The covariance descriptors, known to constitute an efficient signature ... -
Compression of power quality event data using 2D representation
Gerek, Ömer Nezih; Ece, Doğan Gökhan (Elsevier Science Sa, 2008)This paper introduces the energy compaction efficiency of a novel two-dimensional (2D) representation for compression of recorded power quality event data. The 2D representation enables to exploit redundancy across vertical ... -
Covariance analysis of voltage waveform signature for power-quality event classification
Gerek, Ömer Nezih; Ece, Doğan Gökhan; Barkana, Atalay (IEEE-Inst Electrical Electronics Engineers Inc, 2006)In this paper, covariance behavior of several features (signature identifiers) that are determined from the voltage waveform within a time window for power-quality (PQ) event detection and classification is analyzed. A ... -
An Edge-Sensing Predictor in Wavelet Lifting Structures for Lossless Image Coding
Gerek, Ömer Nezih; Çetin, A. Enis (Springer, 2007)The introduction of lifting implementations for image wavelet decomposition generated possibilities of several applications and several adaptive decomposition variations. The prediction step of a lifting stage constitutes ... -
The effect of model generated solar radiation data usage in hybrid (wind-PV) sizing studies
Hocaoğlu, Fatih Onur; Gerek, Ömer Nezih; Kurban, Mehmet (Pergamon-Elsevier Science LTD, 2009)Wind speed and solar radiation characteristics belonging to past years of a region are the main input parameters in wind-photovoltaic hybrid system (WPHS) sizing studies. Classically, these data are fed to several scenarios ... -
Empirical mode decomposition application for short-term flicker severity
Önal, Yasemin; Gerek, Ömer Nezih; Ece, Doğan Gökhan (Tubitak Scientific & Technical Research Council Turkey, 2016)In this article, an approach based on empirical mode decomposition (EMD) is suggested in order to calculate short-term flicker severity, Pst, in power systems. EMD is a new signal processing method used for the analysis ... -
A fast method for the implementation of common vector approach
Koç, Mehmet; Barkana, Atalay; Gerek, Ömer Nezih (Elsevier Science Inc, 2010)In this paper a novel computation method is proposed to perform the common vector approach (CVA) faster than its conventional implementation in pattern recognition. While conventional CVA calculations perform the classification ... -
Feature extraction, selection and classification code for power line scene recognition
Yetgin, Ömer Emre; Gerek, Ömer Nezih (Elsevier Science BV, 2018)Detection and avoiding of power lines and cables is a critical issue in aircraft flight safety. Despite various improvements in image analysis literature, most of the safety issues depend on visual capabilities of pilots. ... -
Harmonic analysis based hourly solar radiation forecasting model
Fidan, Mehmet; Hocaoğlu, Fatih Onur; Gerek, Ömer Nezih (Inst Engineering Technology-Iet, 2015)In this study, a novel two-step hourly solar radiation modelling procedure is developed. In the first step, hourly solar radiation data of a single day is considered and its periodic Fourier series coefficients are calculated. ... -
Hilbert-Huang Transform Based Approach for Measurement of Voltage Flicker Magnitude and Frequency
Önal, Yasemin; Ece, Doğan Gökhan; Gerek, Ömer Nezih (Taylor & Francis Inc, 2015)Voltage flicker is a non-stationary waveform for which direct spectral analysis is not appropriate. To overcome this difficulty, a Hilbert-Huang transform based technique is proposed here. Hilbert-Huang transform is a new ... -
Hourly Forecasting of Long Term Electric Energy Demand Using Novel Mathematical Models and Neural Networks
Başaran Filik, Ümmühan; Gerek, Ömer Nezih; Kurban, Mehmet (Icic Int, 2011)In this work, hourly forecasting of long term electric energy demand is achieved using mathematical models and Artificial Neural Network (ANN) approaches. Previous works regarding energy demand forecasting either treated ... -
Hourly solar radiation forecasting using optimal coefficient 2-D linear filters and feed-forward neural networks
Hocaoğlu, Fatih Onur; Gerek, Ömer Nezih; Kurban, Mehmet (Pergamon-Elsevier Science LTD, 2008)In this work, the hourly solar radiation data collected during the period August 1, 2005-July 30, 2006 from the solar observation station in Iki Eylul campus area of Eskisehir region are studied. A two-dimensional (2-D) ... -
A Hysteresis Model for Fixed and Sun Tracking Solar PV Power Generation Systems
Başaran Filik, Ümmühan; Filik, Tansu; Gerek, Ömer Nezih (MDPI, 2018)In this study, a new solar photovoltaic (PV) panel output power model is proposed. The model is constructed as a function of ambient temperature and solar radiations for two types (fixed panel and sun tracking panel) of ... -
Improved synthetic wind speed generation using modified Mycielski approach
Fidan, Mehmet; Hocaoğlu, Fatih Onur; Gerek, Ömer Nezih (Wiley-Blackwell, 2012)In this paper, novel approaches for wind speed data generation using Mycielski algorithm are developed and presented. To show the accuracy of developed approaches, we used three-year collected wind speed data belonging to ...