Meslek Yüksek Okulu

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Citation - Scopus: 0
A Graphical Speech Analysis Teaching Tool
(Institute of Electrical and Electronics Engineers Inc., 2022) Ozaydin, S.; Özaydın, Selma; 253019; Çankaya Meslek Yüksekokulu
The widespread use of digital speech processing in today's technologies causes many electronics and computer engineering students to need a basic background in these subjects. The paper describes a toolbox designed to support undergraduate or graduate level courses on speech processing. The proposed educational toolbox is designed as a virtual lab for basic operations in digital speech processing-based courses. This graphical user interface (GUI) based speech analysis algorithm is built with six main function modules, which are signal input, noise addition, up-sampling/down-sampling, time domain feature analysis, pitch detection and frequency domain analysis. The toolbox involves different operations for measuring important speech feature parameters such as pitch, energy, zero-crossing ratio, FFT and power spectrum of an input speech signal. The toolbox has also been developed to easily manipulate and add some other possible speech processing methods. It is thought that the tool will make it easier for students to understand the methods that form the basis of digital speech processing, increase the interest in the lesson with its visual outputs, and allow new methods to be added easily when desired thanks to its simple and modular structure. The main aim of this paper to show how such a tool facilitates students understanding of technical concepts introduced in speech courses. © 2022 IEEE.
Citation - Scopus: 3
A Relationship Marketing Strategy in Brand Communication: Influencer Marketing Strategy
(IGI Global, 2019) Ôzsaçmaci, B.; Özsaçmacı, Bülent; Dursun, T.; 19729; Uluslararası Ticaret ve Finansman
Influencer marketing increases brand awareness by generating appropriate content to attract the attention of consumers in a virtual environment in accordance with the brand texture. This chapter explores research to determine importance of influencer marketing in the brand communication area, which is based on relationship marketing. Authors mainly focus on influencer marketing and its connection with relationship marketing. They describe the constituent parts of the topics and illustrate them with the case studies and statistical facts. The authors strongly claim influencer marketing shares similar variables with relationship marketing and their basic keywords are related. © 2020 by IGI Global.
Başkanlık Sistemi Eleştirisi: Karl Marx’ın Mirası
(2019) Kılıç, İlker; 43431; Hukuk
CBS Tabanlı Suç Analizi Yöntemleri
(2013) Maraş, Hadi Hakan; Maraş, Hadi Hakan; 34410; Bilgisayar Mühendisliği
Coğrafi Bilgi Sistemleri (CBS) günlük hayatımızda önemi sürekli olarak artan uygulamalara sahiptir. CBS’nin popüler ve kritik uygulama alanlarından biri de mekânsal suç analizidir. Günümüzde suç oranları artış göstermekte ve bu yüzden suç eğilimlerini analiz etmek ve suçu önleyici tedbirler almak büyük önem arz etmektedir. Suçlar çoğu zaman mekânsal ve zamansal modeller göstermektedir. Örneğin, bazı suç türleri bazı lokasyonlarda nispeten yüksek oranlarda işlenebilmektedir. Bazıları ise gün içinde belli saat aralıklarında yüksek oranlarda olabilmektedir. Klasik suç analiz yöntemlerine coğrafi destek eklemek, tablosal veya istatistiksel metotların sunamayacağı son derece önemli ve müstesna faydalar sağlayabilir. Örneğin, belli bir suç türünün mekânsal dağılımını görmek veya farklı suç türlerinin lokasyonlarını harita üzerinde karşılaştırmak, karar verme pozisyonundaki yöneticilere kritik ve önemli ipuçları verebilir. Bu yüzden, suç analiz yöntemlerine mekânsal boyut katmak emniyet birimlerindeki çalışmalara önemli bir destek sağlamaktadır
Comparative Analysis of Early Studies on Turkish Whistle Language and a Case Study on Test Conditions
(2018) Özaydın, Selma; 253019; Çankaya Meslek Yüksekokulu
This paper examines the early studies on Turkish Whistle Language and it argues that they have some controversial results. The study considers these issues need to be discussed and searched again in terms of linguistic and phonetic form. Unfortunately, there are few research studies on Turkish whistle language and most of them were performed nearly fifty years ago despite the fact that this language still has been used in Kuskoy region. Therefore, the findings of these early research studies could give valuable information to start to a new research study on the subject. The first scientific study on Turkish Whistle language was performed by a French scientist R.G. Busnel with his multidisciplinary research team in 1967. Some of this research’s results were published in the book. A Turkish scientist O. Baskan also participated in Busnel’s research group and published a paper on TWsL in 1968. However, some assertions such as people having a tendency to understand the Turkish whistle language with three vowels and three consonants have not been in the research results of R.G. Busnel. In addition, a Turkish scientist D. Aksan in Turkey had performed another research at Kuskoy region with his own team. Their test methods were different from the previous ones. This paper analyzes these research results on a comparative basis and presents the common and conflicted issues to discuss the uncertain points. The comparative evaluation of these past research studies aims to highlight the controversial position of the results on Turkish Whistle Language. In this scope, this paper opens a discussion about the selection of test conditions for an acoustic and linguistic analysis of the Turkish whistle language.
Citation - WoS: 0
Citation - Scopus: 2
Comparative Performance Analysis of Filtering Methods for Removing Baseline Wander Noise from an ECG Signal
(World Scientific Publ Co Pte Ltd, 2024) Ozaydin, Selma; Özaydın, Selma; Ahmad, Imteyaz; 253019; Çankaya Meslek Yüksekokulu
ECG signals play a vital role in the diagnosis of cardiovascular conditions. However, they often suffer from the effects of various noise sources, including baseline wandering, respiratory artifact noise, power line interference and electrode motion artifacts. To overcome these challenges, it is imperative to implement low-frequency signal noise reduction strategies. Such strategies aim to significantly improve the quality of ECG signals, thus promoting more accurate and reliable diagnosis of cardiovascular disorders. This paper conducts a comparative analysis to assess the effectiveness of commonly used filtering and wavelet techniques in reducing Baseline Wander (BW) noise within ECG signals generated by the influence of breathing or electrode movements. It is common to observe the selection and evaluation of only one particular technique in the existing literature. In contrast, this study aims to provide a comprehensive comparative analysis, providing insight into the performance and relative merits of different techniques. Our research uses both filtering and Discrete Wavelet Transform (DWT) techniques in baseline noise removal. In this context, a reference point is established utilizing noise-free signals and a meticulous investigation of the wavelet-based approach that most effectively eliminates the resulting noise is provided. Subsequently, we assess the reference input and output signal via Signal-to-Noise Ratio (SNR) and Kolmogorov-Smirnov statistical test measurements. The most important contribution of this work to the scientific community resides in the comprehensive examination of IIR/FIR-based and wavelet method-based filtering methods capable of yielding the highest SNR levels across various ECG signals with various types of BW noise. Additionally, the effectiveness of the Chebychev-II filter in BW noise removal is highlighted. Our study was conducted using the MATLAB platform and code command lines were shared to facilitate the reproduction of our study by other researchers. It is considered that this study will be an important reference in the selection of effective techniques for removing BW noise within ECG signals.
Citation - Scopus: 1
Design of a Voice Activity Detection Algorithm based on Logarithmic Signal Energy
(Institute of Electrical and Electronics Engineers Inc., 2022) Ozaydin, S.; Özaydın, Selma; 253019; Çankaya Meslek Yüksekokulu
This article presents a new method for calculating the signal energies of speech segments in voice activity detection algorithms. In the study, the μ-law signal compression method is adapted to calculate short-term signal energies. A simple voice activity detection (VAD) algorithm is designed to demonstrate the effectiveness of the proposed method. The same VAD algorithm was also run with two different conventional energy calculation formulas and the performance of each VAD was evaluated using time-domain short-time energy features. The G729 standard VAD algorithm was also used for performance comparison. During the test of the analyzed detectors, many kinds of input speech signals with various types of background environmental noise, such as restaurants, vehicles, and streets, were tested. Using the new energy calculation method, the VAD detector has improved detection accuracy compared to VAD detectors based on the other two energy methods and was able to effectively identify voice-active regions even in noisy conditions at low SNR levels. The results revealed that the VAD detector designed with the proposed new energy calculation formula outperforms traditional energy-based voice activity detection methods and provides noticeable increases in detection rate even under adverse conditions. © 2022 IEEE.
Doğrusal Olmayan Bootstrap Koentegrasyon Testleri: OECD Ülkeleri için Satın Alma Gücü Paritesi Üzerine Bir Uygulama
(2018) Uçar, Nuri; Güler, Hüseyin; 189073; Bankacılık ve Finans
Bu çalışmanın doğrusal olmayan panel eşbütünleşme testleri önermesinin dışında ekonometri literatürüne ikinci katkısı ise, doğrudan eşbütünleşme testleri elde etmek yerine, uzun dönem denklemden elde edilen hata tahminlerinin hata düzeltme modellerine uzun dönem değişken olarak eklenip, doğrusal olmayan panel eşbütünleşme testlerini bu modeller üzerinden geliştirecek bootstrap yöntemi öne sürmesidir. Uygulamada, Bootstrap hipotez testleri, Monte Carlo yöntemiyle kritik değerler üretilip, bu kritik değerlere göre değerlendirilmiştir. Bootstrap tahminler için -hem parametre hem de istatistikler- Matlab da kod yazılmıştır. Üretilen eşbütünleşme testleri OECD ülkeleri için, Satın Alma Gücü Paritesi için uzun dönem ilişkinin olup olmadığını test etmek için kullanılmışlardır. Bu uygulamadan elde edilen sonuçlara göre, "diğer ülkelerde" uzun dönem ilişki varken, G7 ülkelerinde ise gözlemlenmemiştir. Satın Alma Gücü Paritesinin iki gurup arasında farklılaşması, ilginç bir sonuçtur. Veri seti oluştururken 2008 krizi dikkate alınarak oluşturulmuştur. Krizin 5 yıl öncesi ve sonrası veri setine dâhil edilmiştir. Buradaki amaç kriz şokunu ortak bir faktör olarak düşünmek ve bu faktörün yatay kesitte bağımlılığa neden olduğunu dikkate alarak bootstrap yaklaşımı ile parametre tahminlerini gerçekleştirmektir. Ayrıca, kriz öncesi dönemi kapsayan veriler içinde Satın Alma Gücü Paritesi araştırılmıştır. Tüm ülkeleri dikkate aldığımızda, kriz dönemini içeren 2003.01-2013.01 dönemi ile kriz öncesi dönem farklılaşmaktadır. Kriz öncesi doğrusal olmayan eşbütünleşme gözükürken, kriz döneminde böyle bir şey söz konusu değildir. Krizin neden olduğu ekonomik şokun ülke ekonomilerinde enflasyon ve döviz kuru verilerinde birlikte kırılmalara (co-breaking) neden olması bu değişkenler arasında doğrusal olmayan eşbütünleşmenin varlığı yönünde beklentiye neden olabilir. Bu doğrusal olmayan yapının "diğer ülkelerde" varlığını göstermesi fakat "G7" ülkelerinde ise eşbütünleşmenin gözlemlenmemesi, bu ülkelerin bu süreçte birbirlerinden ayrıştıklarını da göstermektedir Ekonometri teorisi açısından, bu çalışmada ortaya atılan testlerin istatiksel ve asimptotik özellikleri geliştirilmeye açıktır. Ayrıca, burada önerilen doğrusal olmayan testler uygulama açısından sadece bootstrap yaklaşımı ile değil, diğer yatay kesit bağımlılığını dikkate alan panel veri analizi içerisinde de geliştirilmeye uygundur. Uygulama aşamasında ise, döviz kurundaki değişen varyans problemini dikkate alan test istatistikleri ışığında Satın alma Gücü Paritesi geliştirilebilir.
Doğrusal Olmayan Panel Eşbütünleşme Testleri Kullanılarak Fisher Etkisinin OECD Ülkeleri İçin Araştırılması
(2018) Uçar, Nuri; 189073; Bankacılık ve Finans
Citation - Scopus: 0
ECG Signal Denoising with SciLab
(Ismail Saritas, 2023) Ahmad, I.; Özaydın, Selma; Ozaydin, S.; 253019; Çankaya Meslek Yüksekokulu
This paper presents a study on de-noising electrocardiogram (ECG) signals using Scilab, an open-source software package known for its signal processing capabilities. ECG signals are often contaminated by various noise sources, which can reduce the accurate diagnosis and monitoring of heart health. In this work, digital signal processing methods such as Finite Impulse Response (FIR) and Infinite Impulse Response (IIR) filters are used to effectively suppress noise while preserving the essential features of the ECG waveform. We explore main noise sources that commonly affect ECG recordings, such as baseline wandering noise, power-line interference, and muscle artifacts, and discuss their respective challenges. The de-noising methods has been extensively evaluated and demonstrated its ability to improve signal quality and diagnostic accuracy by eliminating noise artifacts. The results highlight Scilab's potential for de-noising ECG signals and its importance in improving patient care and biomedical signal processing applications. The efficacy of the de-noising methods is thoroughly evaluated through comparative analyses with other commonly used de-noising approaches. Experimental results demonstrate its superiority in preserving the QRS complex while efficiently eliminating noise artifacts, leading to more accurate and reliable diagnostic information. In conclusion, this paper presents a comprehensive study on de-noising ECG signals using Scilab, offering a valuable contribution to the field of biomedical signal processing. Researchers and practitioners in the domain of ECG signal processing can benefit from the insights and techniques presented herein to advance their studies and further applications. © 2023, Ismail Saritas. All rights reserved.
Eğitime Giriş
(Pegem Akademi, 2019) Ökdem, Meltem; 45368; Ortak Dersler Bölümü
Enflasyon ve büyüme belirsizliklerinin enflasyon ve büyüme ile olan ilişkileri: Türkiye örneği
(Çankaya Üniversitesi, 2008) Omay, Tolga; 19320; Çankaya Meslek Yüksekokulu
Çalışmada iki değişkenli Genelleştirilmiş Otoregresif Koşullu Değişen Varyans modeli yardımıyla büyüme, enflasyon oranı ve belirsizliklerinin arasındaki Granger nedensellik ilişkileri incelenmiştir. Türkiye ekonomisine uygulanan çalışma, 1986:6-2007:1 dönemini kapsamakta ve bu dönem 3 farklı alt döneme (1986:6-1994:3/1994:5-2001:1/2003:3-2007:1) ayrılarak analiz genişletilmektedir. Tam dönem ve alt dönemler itibari ile elde edilen sonuçlar doğrultusunda, merkez bankasının fiyat istikrarını korumasına yönelik politika duruşunun optimal olduğu sonucuna varılmıştır.
Evaluation of Acoustic Phonetic Properties of Turkish Whistle Language
(2018) Özaydın, Selma; 253019; Çankaya Meslek Yüksekokulu
Citation - WoS: 3
Citation - Scopus: 3
Firm Survival in Times of Crisis: Do Innovation and Financing Constraints Matter? Insights from the COVID-19 Pandemic
(Routledge Journals, Taylor & Francis Ltd, 2023) Ozsuca, Ekin Ayse; 237965
Utilizing survey data collected over three rounds, this paper investigates the impact of pre-COVID innovation performance, innovation type, sources of knowledge, and the moderating role of financial constraints on survival following the outbreak of COVID-19. The findings pinpoint a strong and positive link between firm survival and innovation, especially process innovation, confirming the ability of innovators to adapt to new conditions as a determinant of survival. Moreover, relying on internal knowledge is found to increase the chance of survival and adaptability to times of crisis. The results further indicate that access to finance strengthens the positive impact of innovation on firm survival/adaptation.
Kanun hükmünde kararnameler ve kapitalizmin ruhu
(2012) Kılıç, İlker; 43431; Hukuk
Marka Birleşmeleri
(Gazi Kitabevi, 2018) Özsaçmacı, Bülent; 19729; Uluslararası Ticaret ve Finansman
Citation - WoS: 20
Citation - Scopus: 23
Nonlinearities in emerging stock markets: evidence from Europe's two largest emerging markets
(Routledge Journals, Taylor & Francis Ltd, 2008) Hasanov, Muebariz; Omay, Tolga; Omay, Tolga; Çankaya Meslek Yüksekokulu
Recent developments in time series analysis allow proper modelling of nonlinearities in economic and financial variables. A growing body of research was dedicated to investigation of potential nonlinearities in conditional mean of many economic and financial variables, mainly concentrating in developed economies. However, nonlinearities in financial variables in developing economies have not been fully examined yet. In this article we investigate potential nonlinearity and cyclical behaviour of stock returns in Europe's two largest emerging stock markets, mainly in the Greek and Turkish stock markets. Specifically, we use STAR family models, which allow to model nonlinearities in the conditional mean, for modelling monthly returns on stock exchange indices of the Athens Stock Exchange and Istanbul Stock Exchange. Although we find no nonlinearity in conditional variance, we do find strong evidence in favour of nonlinear adjustment of stock returns. It is found that allowing for nonlinearity in conditional mean results in a superior model and provides good out-of-sample forecasts, which contradicts to efficient market hypothesis.
Citation - WoS: 65
Citation - Scopus: 80
Re-examining the threshold effects in the inflation-growth nexus with cross-sectionally dependent non-linear panel: Evidence from six industrialized economies
(Elsevier Science Bv, 2010) Omay, Tolga; Omay, Tolga; Kan, Elif Oeznur; Çankaya Meslek Yüksekokulu
This paper analyzes the empirical relationship between inflation and output growth using a novel panel data estimation technique, Panel Smooth Transition Regression (PSTR) model, which takes account of the non-linearities in the data. By using a panel data set for 6 industrialized countries that enable us to control for unobserved heterogeneity at both country and time levels, we find that there exists a statistically significant negative relationship between inflation and growth for the inflation rates above the critical threshold level of 2.52%, which is endogenously determined. Furthermore, we also control cross-section dependency by using the CD test modified to non-linear context and remedy cross-section dependency with Seemingly Unrelated Regression Equations through Generalized Least Squares (SURE-GLS) and newly proposed Common Correlated Effects (CCE) estimation techniques. We find that these methods change the critical threshold value slightly. The estimated threshold values from these estimation methods are 3.18% and 2.42%, respectively. (C) 2010 Elsevier B.V. All rights reserved.
Rethinking Fisher Effect with New Keynesian Phillips Curve
(2019) Uçar, Nuri; 189073; Bankacılık ve Finans
I modify and enlarge the simple Fisher equation by including different inflation dynamics and multiple common unobservable factors. I investigate the long runrelationship by carrying out a series of estimators and models that have been developed recently. I observe that augmentation of Fisher equation leads to provide the supportive evidence for the long run relationship between nominal interest rate and inflation.
Citation - Scopus: 5
Speech Denoising with Maximal Overlap Discrete Wavelet Transform
(Institute of Electrical and Electronics Engineers Inc., 2022) Alak, I.K.; Özaydın, Selma; Ozaydin, S.; 253019; Çankaya Meslek Yüksekokulu
In this paper, the effectiveness of the maximum overlapping discrete wavelet transform (MODWT) method on denoising the speech signal is tested and examined. Ensuring the intelligibility of the speech signal in noisy environments by separating it from the noise is a widely researched topic today. On the other hand, being able to recover the original speech from the noisy signal with minimal distortion is a challenge due to the difficulties in removing the background noise. Numerous factors in environmental noise environments can interfere with the signal. In this study, the performance of some discrete wavelets transform methods is experimentally analyzed using different wavelet filters. The analysis program was carried out in the MATLAB environment. As the input noise speech signal, speech sounds containing different environmental background noises (train, car, station, plane, etc.) were analyzed. During the tests, these noisy input signals were filtered out from the speech signal by wavelet analysis. The input noisy speech signal is decomposed into wavelet coefficients with different thresholding methods. The reconstructed speech was compared by measuring the signal-to-noise ratio (SNR) values between the noisy input signal and the smoothed output signals. The scientific contributions of the study include a detailed comparative analysis of the performances of various wavelet methods against different background environmental noises. © 2022 IEEE.

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