Bilgi İşlem Daire Başkanlığı
Bu koleksiyon için kalıcı URI
Güncel Gönderiler
Öğe Measurement of iron mass in concrete wall using ultra-wide band radar(Inst Engineering Technology-Iet, 2019) Kocadağ, Fatih; Çınar, Rıdvan Fırat; Demirkol, AşkınHere, it is aimed to measure and detect the iron mass of a concrete solid wall, column, floor by using of ultra-wide band radar. Electromagnetic waves boundary conditions, reflection, and refraction of waves that radiate in solid material are analysed. GPR imaging methodology and scanning types such as A, B, and C are analysed. Ultra-wide band radar imaging is used for detecting measuring the diameter of the iron material.Öğe Kalman filter aided target density function for radar imaging(Inst Engineering Technology-Iet, 2019) Çınar, Rıdvan Fırat; Kocadağ, Fatih; Demirkol, AşkınThis study proposes a new algorithm for air target radar imaging by taking the geometrical and processing advantages of array antenna systems. The backscattered signal is processed with a new technique to benefit the facilities of angular scanning. In order to virtually increase the number of the radar elements of the array system, a powerful optimal estimator is employed, namely Kalman filter.Öğe Twittersentidetector: a domain-independent twitter sentiment analyser(Taylor & Francis Inc, 2018) Kabakuş, Abdullah Talha; Kara, ResulSentiment analysis has become more crucial after the rise of social media, especially the Twitter since it provides structured and publicly available data. TwitterSentiDetector is a domain-dependent and unsupervised Twitter sentiment analyser that focuses on the differences occurred by the informal language used in Twitter. TwitterSentiDetector uses natural language processing techniques alongside the proposed linguistic methods to classify sentiments of tweets into positive, negative, and neutral through the polarity scores obtained from sentiment lexicons. According to tests on widely used Twitter data-sets that contain manually detected sentiments labels alongside tweets, TwitterSentiDetector's sentiment detection ratio is calculated as up to 69%. When the target sentiment classes are decreased to positive and negative, the detection ratio is increased up to 87%. The results are calculated very similarly when the same data-set is evaluated by the proposed tweet-level context aware sentiment analysis module which confirms the validity of each approach.Öğe A survey of spam detection methods on Twitter(Science & Information Sai Organization Ltd, 2017) Kabakuş, Abdullah Talha; Kara, ResulTwitter is one of the most popular social media platforms that has 313 million monthly active users which post 500 million tweets per day. This popularity attracts the attention of spammers who use Twitter for their malicious aims such as phishing legitimate users or spreading malicious software and advertises through URLs shared within tweets, aggressively follow/unfollow legitimate users and hijack trending topics to attract their attention, propagating pornography. In August of 2014, Twitter revealed that 8.5% of its monthly active users which equals approximately 23 million users have automatically contacted their servers for regular updates. Thus, detecting and filtering spammers from legitimate users are mandatory in order to provide a spam-free environment in Twitter. In this paper, features of Twitter spam detection presented with discussing their effectiveness. Also, Twitter spam detection methods are categorized and discussed with their pros and cons. The outdated features of Twitter which are commonly used by Twitter spam detection approaches are highlighted. Some new features of Twitter which, to the best of our knowledge, have not been mentioned by any other works are also presented.Öğe Graph-based sentence level spell checking framework(Inst Integrative Omics & Applied Biotechnology, 2017) Kabakuş, Abdullah Talha; Kara, ResulSpelling mistakes are very common on the web, especially when it comes to social media, it is much more common since (1) users tend to use an informal language that contains slang, and (2) the character limit defined by some social services such as Twitter. Traditional string similarity measurements (1) do not consider the context of the misspelled word while providing alternatives, and (2) do not provide a certain way to choose the right word when there are multiple alternatives that have the same similarity with the misspelled word. Therefore, we propose a novel sentence level spell checking framework that targets to find "the most frequently used similar alternative word". 146,808 sentences from different corpora are stored in a graph database. The similarity is calculated by using Levenshtein distance algorithm alongside the similarity between two given words. As the experimental results are presented in the discussion, the proposed framework is able to correct misspellings which cannot be corrected by traditional string similarity measurement based approaches. The accuracy of the proposed framework is calculated as 84%. Since the proposed framework uses a slang dictionary to determine misspelled words, it can be used to correct misspellings in the social media platforms.Öğe A performance evaluation of in-memory databases(Elsevier, 2017) Kabakuş, Abdullah Talha; Kara, ResulThe popularity of NoSQL databases has increased due to the need of (1) processing vast amount of data faster than the relational database management systems by taking the advantage of highly scalable architecture, (2) flexible (schema-free) data structure, and, (3) low latency and high performance. Despite that memory usage is not major criteria to evaluate performance of algorithms, since these databases serve the data from memory, their memory usages are also experimented alongside the time taken to complete each operation in the paper to reveal which one uses the memory most efficiently. Currently there exists over 225 NoSQL databases that provide different features and characteristics. So it is necessary to reveal which one provides better performance for different data operations. In this paper, we experiment the widely used in-memory databases to measure their performance in terms of (1) the time taken to complete operations, and (2) how efficiently they use memory during operations. As per the results reported in this paper, there is no database that provides the best performance for all data operations. It is also proved that even though a RDMS stores its data in memory, its overall performance is worse than NoSQL databases. (C) 2016 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.Öğe Kalman Filter and Particle Swarm Optimization on real time satellite tracking(Ieee, 2016) Kocadağ, Fatih; Çınar, Rıdvan Fırat; Demirkol, AşkınIn this study, it is aimed to tracking a satellite on mobile vehicles for receiving the broadcasting signal of the satellite. Satellite tracking is used in many areas on mobile platforms. Too many problems come with the mobility. A robust tracking algorithm is need for overcome such problems. The robust satellite tracking case is researched and test software is developed for Android based platforms. Satellite tracking can be done with a receiver antenna by adjusting the positions according to the movements of the vehicle. Therefore Kalman Filter and Particle Swarm Optimization algorithm are compared in the use of satellite tracking process. An Android based application was developed to accomplish this and tests were performed using an android - based device on a mobile vehicle. Test data were collected through application from the sensors of the android device. Orientation and location data of the mobile vehicle are collected from the device sensors and they are used in computation of the azimuth and elevation angles of receiver antenna. Two well-known algorithms were implemented and performed on the application for tracking to keep satellite link online. It was systemically investigated the estimation and computational performance of the two algorithm on this subject. The results and test cases were analyzed and discussed. Test cases cover the computation of the azimuth and elevation angles.Öğe Real time tracking of TV satellites on moving vehicles using Kalman filter(Ieee, 2015) Kocadağ, Fatih; Demirkol, AşkınThis paper presents a real time tracking of TV satellites on mobile vehicles using Kalman filter. Kalman filter is adapted to tracking the satellite for uninterrupted broadcasting on moving vehicles. Information about the real time position of the vehicle and satellite is gathered with the aid of onboard sensors on an android device and then analyzed on an android based application. A real time application has been implemented continuously to calculate the azimuth and elevation angle of the satellite. Accelerometer and magnetometer sensors are used for collecting the information on the position of the antenna. GPS sensor is used for collecting the latitude and longitude data of the vehicle. These data are then used for calculating the azimuth and elevation angle of a parabolic dish antenna.Öğe APK auditor : permission-based Android malware detection system(Elsevier Sci Ltd, 2015) Kabakuş, Abdullah Talha; Doğru, İbrahim Alper; Aydın, ÇetinAndroid operating system has the highest market share in 2014; making it the most widely used mobile operating system in the world. This fact makes Android users the biggest target group for malware developers. Trend analyses show large increase in mobile malware targeting the Android platform. Android's security mechanism is based on an instrument that informs users about which permissions the application needs to be granted before installing them. This permission system provides an overview of the application and may help gain awareness about the risks. However, we do not have enough information to conclude that standard users read or digital investigators understand these permissions and their implications. Digital investigators need to be on the alert for the presence of malware when examining Android devices, and can benefit from supporting tools that help them understand the capabilities of such malicious code. This paper presents a permission-based Android malware detection system, APK Auditor that uses static analysis to characterize and classify Android applications as benign or malicious. APK Auditor consists of three components: (1) A signature database to store extracted information about applications and analysis results, (2) an Android client which is used by end-users to grant application analysis requests, and (3) a central server responsible for communicating with both signature database and smartphone client and managing whole analysis process. To test system performance, 8762 applications in total, 1853 benign applications from Google's Play Store and 6909 malicious applications from different sources were collected and analyzed by the system developed. The results show that APK Auditor is able to detect most well-known malwares and highlights the ones with a potential in approximately 88% accuracy with a 0.925 specificity. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Ayrık kosinüs dönüşümü kullanarak EEG sinyallerinden otomatik epilepsi teşhisi(Institute of Electrical and Electronics Engineers Inc., 2020) Demirezen Yağmur, Fatma; Sertbaş, AhmetIn this study, 1-dimensional (1D) biomedical signal analysis based on the Discrete Cosine Transform (DCT) feature extraction method was performed to diagnose high-accuracy epilepsy disease. For the diagnosis of epilepsy, Electroencephalogram (EEG) data were used for 1-dimensional (1D) signal analysis. In addition to DCT, statistical methods such as mean, variance, standard deviation, kurtosis, skewness were applied to 1-dimensional EEG data. The most useful features were selected by applying PCA, LDA, Forward Selection and Backward Selection methods to the obtained feature vectors. EEG features of Healthy, and Epilepsy classification was made as a two-cluster. As a result of the classification realized by the Multilayer Perceptron ANN method; 96% success of 1-dimensional EEG data by using the PCI method selected features. Removing artefacts the original EEG data with ICA (Independent Component Analysis) and statistical calculation of their feature coefficients with AKD was more successful than AKD methods used in the literature. © 2020 IEEE.Öğe Diagnosis of epilepsy in brain MR images using DCT-means [DCT ortalamalari kullanarak beyin MR görüntülerinden epilepsi teşhisi](Institute of Electrical and Electronics Engineers Inc., 2018) Yağmur, Fatma Demirezen; Sertbaş, AhmetEpilepsy is a condition of clinical disease caused by the appearance of seizures originating from sudden electrical changes in brain cells. Magnetic Resonance Imaging (MRI) is used to understand why these seizures originate in the brain. Discrete Cosine Transform (DCT) and Arithmetic Mean method were used to extract the properties. The feature vectors were classified by using Artificial Neural Networks, and the accuracy of training was determined as 98.8% in this classification. The classification was evaluated regarding accuracy and time. © 2018 IEEE.Öğe Problem çözme sürecinde beyin dalgalarının incelenmesi(2014) Dündar, Sefa; Bulut, Mehmet; Canan, Sinan; Özlü, Özkan; Kaçar, SezginBilişsel sinirbilimin eğitime sunduğu fırsatlardan birisi de öğrenme sürecinde bireysel farklılıkların anlaşılmasını sağlamasıdır. Dolayısıyla eğitimde sinirbiliminden faydalanabilmek için disiplinler arası çalışmalara ihtiyaç duyulmaktadır. Bu disiplinler arası araştırmalar matematiksel düşüncenin nerde ve nasıl oluştuğuna dair bulgulara ulaşabilmek için önemli görevler üstlendiklerini söyleyebiliriz. Sinirsel mekanizmaların anlaşılmasına katkı sağlayabilmek için bu araştırmada farklı bilişsel stillere sahip öğrencilerin aritmetik problemlerini çözme sürecindeki beyin aktiviteleri elektrofizyolojik olarak incelenmiştir. Bilişsel stilleri farklı olan öğrencilerin aritmetik problemleri çözerken beyin dalgalarına ait asimetri indeks değerlerinin loblara göre analizi yapıldığında istatiksel olarak anlamlı farklılıklar belirlenmiştir. Analiz sonuçları belirlenerek yorumlar yapılmıştır. Bu bağlamda, bilişsel stilleri farklı olan öğrencilerin problem çözme sürecinde beyin aktivasyon yapısı farklılık göstermektedir.Öğe Survey of instant messaging applications encryption methods(2015) Kabakuş, Abdullah Talha; Kara, ResulAnlık mesajlaşma uygulamaları, kolay kullanımları ve popülaritelerinden dolayı geleneksel Kısa Mesajlaşma Servisi (SMS) ve Çoklu Medya Mesajlaşma Servisi (MMS)'in yerini aldı. Anlık mesajlaşma uygulama kullanıcıları, bu uygulamalar aracılığıyla metin, ses mesajları, fotoğraf, video, kişi bilgisi gibi çeşitli türlerdeki ekleri arkadaşlarıyla gerçek zamanlı olarak paylaşabilmektedir. Anlık mesajlaşma uygulamaları Kısa Mesaj Servisi Teknik Gerçeklemesi (GSM) yerine sadece günümüzde en çok kullanılan iletişim aracı olan internete ihtiyaç duyduğundan dolayı ücretsizdir. Buradaki kritik nokta, siber saldırganlarına ve bilgisayar korsanlarına karşı herhangi açık nokta bırakmamak için bu mesajların güvenliğinin sağlanmasıdır. PricewaterhouseCoopers tarafından yapılan son rapora göre, 2014 yılında tespit edilen uluslararası siber saldırılar sayısı 42.8 milyona çıkarak %48'e yükselmiştir. Postini güvenlik şirketi tarafından yayınlanan başka bir rapor ise anlık mesajlaşmayı hedefleyen tehditlerin %90'ının oldukça yıkıcı soluncanlar olduğunu belirtmektedir. Bu çalışmada, anlık mesajlaşma uygulamalarının şifreleme yöntemleri karşılaştırmalı olarak sunulmuştur. Anlık mesajlaşma uygulamaları üç farklı platform göz önüne alınarak incelenmiştir: (1) Masaüstü istemcileri, (2) web istemcileri ve (3) mobil telefon istemcileri. Anlık mesajlaşma uygulamaları, birçok araştırmada en çok üzerinde durulan kritik kriterler olan (1) internet üzerinden metin dönüşümü, (2) şifreleme sonrası metin dönüşümü ve (3) Güvenli Giriş Katmanı (SSL) kullanıldıktan sonra yapılan metin dönüşümüne göre karşılaştırılmıştır. Son olarak yazarlar, güvenli bir mesajlaşma uygulamasında bulunması gereken kritik gereksinimleri vurgulamıştırÖğe The importance of informatics for health care industry(2016) Kabakuş, Abdullah Talha; Kara, ResulThere is no industry that does not benefit from the advantages of information technology (IT). Health care industry is no different from them.
