240 research outputs found
The Impact of Text Representation and Preprocessing on Author Identification
No full textAuthor identification, one of the popular topics in text classification and natural language processing, basically aims to determine the author of a given text through various analyses. In the literature, different text representation approaches and use of preprocessing steps are considered for author identification problem. This paper aims to comprehensively examine the impact of text representation and preprocessing steps on author identification specifically for Turkish language. For this purpose, the contributions of all possible combinations of different text representation approaches, namely unigram and bigram, together with the preprocessing tasks, including stemming and stop-word removal, to the performance of author identification are investigated. For the experimental evaluation, a brand new dataset is constituted. Also, two different classification algorithms, namely Multinomial Naive Bayes and Sequential Minimal Optimization, are employed. The results of the experimental analysis reveal that using bigram features alone should be avoided. Besides, it is shown that stop-words should be kept inside the text while stemming can be preferred depending on the classification algorithm so that higher performance can be achieved for author identification.Author identification, one of the popular topics in text classification and natural language processing, basically aims to determine the author of a given text through various analyses. In the literature, different text representation approaches and use of preprocessing steps are considered for author identification problem. This paper aims to comprehensively examine the impact of text representation and preprocessing steps on author identification specifically for Turkish language. For this purpose, the contributions of all possible combinations of different text representation approaches, namely unigram and bigram, together with the preprocessing tasks, including stemming and stop-word removal, to the performance of author identification are investigated. For the experimental evaluation, a brand new dataset is constituted. Also, two different classification algorithms, namely Multinomial Naive Bayes and Sequential Minimal Optimization, are employed. The results of the experimental analysis reveal that using bigram features alone should be avoided. Besides, it is shown that stop-words should be kept inside the text while stemming can be preferred depending on the classification algorithm so that higher performance can be achieved for author identification
Evaluation of Cardiovascular Involvement in Pediatric Behcet’s Disease: Case Report with Intracardiac Trombus and Literature Review
No full textHealty Lifestyle Behaviours of the Cardiovascular Heart Disease Patients
No full textPersil Özkan, Özlem (Arel Author), Büyükünal, Serkan Kemal (Arel Author), Şakar, Şule (Arel Author) --- Conference : 13th International Congress of Update in Cardiology and Cardiovascular Surgery March 23-26, 2017 Çeşme, Izmir-Turkey.
Kardiyovasküler hastalık tanısı olan hastalarda sağlıklı yaşam biçimi davranışlarının değerlendirilmesi
No full text#nofulltext# --- Persil Özkan, Özlem (Arel Author), Büyükünal, Serkan Kemal (Arel Author), Şakar, Şule (Arel Author) --- Conference : 6. Ulusal Sağlıklı Yaşam Sempozyumu 1. Yaşam İçin Beslenme ve Spor Kongresi. İstanbul, 24-27 Mayıs 2017.
Computing reliability indices of repairable systems via signature
No full textEryilmaz, Serkan/0000-0002-2108-1781The purpose of this paper is to show the usefulness of system signature for computing some important reliability indices of repairable systems. In particular, we obtain signature-based expressions for stationary availability, rate of occurrence of failure, and mean time to the first failure of repairable systems. Using these expressions we compute corresponding reliability indices of all systems with three and four components. Computational results are also presented for consecutive-k-within-m-out-of-n:F and m-consecutive-k-out-of-n:F systems. (C) 2013 Elsevier B.V. All rights reserved.Scientific and Technological Research Council of Turkey, TUBITAK [110T559]The author thanks the referee for his/her helpful comments and suggestions, which were useful in improving the paper. This work is partially supported by the Scientific and Technological Research Council of Turkey, TUBITAK Project No. 110T559
Cosmology of hidden sector with Higgs portal
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. 67-75).In this thesis, we are investigating cosmological implications of hidden sector models which involve scalar fields that do not interact with the Standard Model gauge interactions, but couple directly to the Higgs field. We particularly focus on their relic particle density as a candidate for dark matter. For the case of hidden sector without a gauge field we have improved the accuracy of the bounds on the coupling constant and give bounds on the Lagrangian parameters. Models with Abelian and non-Abelian gauge fields are also studied with relic density bounds, BBN and galactic dynamics constraints. Several discussions on phase transitions and alternative dark matter candidates are included.by Serkan Cabi.Ph.D
Analytical assessment of optimal number and placement of sensors for modal response estimation of frame buildings
No full textContinuous monitoring of the structural health of buildings can be achieved by placing acceleration sensors at various locations on the structure. Considerable variations in the dynamic response captured through these measurements can be used to identify damage due to aging or extreme load effects. Accurate estimation of modal dynamic behavior using acceleration measurements is critical for efficient structural health monitoring (SHM) of buildings under limited economic resources. In this study, an analytical approach is presented to determine theoretically the optimal number and placement of sensors in a typical five-story reinforced concrete frame building, ensuring that accuracy in modal response is not compromised. In this regard, acceleration responses at each floor level are recorded from time-history analyses of the building’s finite element model under several earthquake ground motions, simulating a complete set of SHM system measurements during seismic events. Then, considering exhaustive search optimization for sensor placement, the operational modal analysis method of Enhanced Frequency Domain Decomposition (EFDD) is applied to extract modal parameters such as the first-mode natural frequency, damping ratio, and mode shape from the simulated monitoring data. The accuracy of the estimated modal parameters from different sensor design alternatives is compared with those from the benchmark sensor configuration to determine the optimal number and locations of sensors. The findings of this research also highlight the importance of using different modal identification methods in SHM. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025
A pseudo-spectral method based on reproducing kernel for solving the time-fractional diffusion-wave equation
No full textIn this paper, we focus on the development and study of the finite difference/pseudo-spectral method to obtain an approximate solution for the time-fractional diffusion-wave equation in a reproducing kernel Hilbert space. Moreover, we make use of the theory of reproducing kernels to establish certain reproducing kernel functions in the aforementioned reproducing kernel Hilbert space. Furthermore, we give an approximation to the time-fractional derivative term by applying the finite difference scheme by our proposed method. Over and above, we present an appropriate technique to derive the numerical solution of the given equation by utilizing a pseudo-spectral method based on the reproducing kernel. Then, we provide two numerical examples to support the accuracy and efficiency of our proposed method. Finally, we apply numerical experiments to calculate the quality of our approximation by employing discrete error norms. © 2022, The Author(s)
Miyokard İnfarktüsü Geçirmiş Hastaların Yaşam Kalitesinin Değerlendirilmesi
No full textKaptan, Gülten (Arel Author), Büyükünal, Serkan Kemal (Arel Author)Bu araştırma biri devlet diğeri üniversite hastanesi olmak üzere iki ayrı hastanenin dahiliye ve koroner yoğun bakım ünitelerinde miyokard infarktüsü (MI) geçirmiş hastaların yaşam kalitesini belirlemek amacı ile yapıldı. Araştırmanın örneklemini MI geçirmiş, araştırmaya katılmayı kabul eden 75 hasta oluşturdu. Araştırmanın verileri araştırmacılar tarafından geliştirilen anket formu ve Kardiyak Versiyon III Skalası kullanılarak yüz yüze görüşme tekniği ile toplandı. Verilerin analizinde Independent-Samples T-test, Mann Whitney U testi kullanıldı. Araştırmada yer alan hastaların yaş ortalaması 60 olarak hesaplandı. Hastaların medeni durumu, gelir durumu, aile içindeki konumu, hastaneye yatış sayısı, MI geçirmelerini yaşam şekillerine bağlama durumu, MI hakkında bilgiye sahip olma durumu, taburculuk sonrası evde bakım uygulanma durumlarının yaşam kalitesi puan ortalamalarını etkilediği saptandı. Araştırma sonucunda, MI geçirmiş hastaların yaşam kalitesini çeşitli faktörlerin etkilediği ve bu faktörlerin ileride yapılacak çalışmalarla araştırılması gerektiği kanısına varıldı
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