Müge Değirmenci Camcı, Synthesis of Realistic 3D Artifacts Using Flow Fields

There is a high demand for realistic computer aided imagery by many applicatiion areas such as games and movies. Due to the complicated characteristics of certain natural phenomena such as fire, smoke or mist, it is difficult to realistically mimic these effects. There are various approximation methods to visually synthesize lifelike 3D artifacts. The use of flow fields to guide the motion of particles creates a random but natural-looking effect. The aim of this study is to use flow fields to generate realistic 3D visual effects.

Date: 06.12.2019 / 13:00 Place: B-116

English

Melih Turhanlar, Detecting Turkish Phishing Attacks With Machine Learning Classifiers

Msc. Candidate: Melih Turhanlar

Program: Cybersecurity

Date:  06.11.2019 13:30

Place: A-108

Abstract: Phishing Attacks are a type of social engineering attack which aims to steal victim’s credit card numbers, credentials, and personal information by using victim’s curiosity and fear emotions. On these attacks, attackers send link with a text which triggers the victim's curiosity and fear emotions. If victim panic with the text inside attack vector and click the link, then victim connects to so-called web server or site which looks like a real web site but actually under control of the attacker. By filling the HTML forms inside the so-called web site, victims send their credentials unwittingly not to the real web site but actually to the attacker. In this study, we focused on phishing attacks with Turkish text in it. The data that we have used in that study contains not only Turkish phishing emails, but also Turkish phishing SMS and tweets that we gathered from the internet during the study. Focusing on Turkish texts inside the attacker’s attack vector, with Logistic Regression Synthetic Minority Over-Sampling Technique (0.923) F1 score has been achieved on our imbalanced dataset which we have created that can be used in other academic researches.

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SALVA DANESHGADEH ÇAKMAKÇI, A NOVEL ONLINE APPROACH TO DETECT DDOS ATTACKS USING MAHALANOBIS DISTANCE AND KERNEL-BASED LEARNING

PhD Candidate: SALVA DANESHGADEH ÇAKMAKÇI 
Program: Information Systems
Date: 22.11.2019 10:00
Place: Conference Hall 1

Abstract: Distributed denial-of-service (DDoS) attacks are constantly evolving as the computer and networking technologies and attackers’ motivations are changing. In recent years, several supervised DDoS detection algorithms have been proposed. However, these algorithms require a priori knowledge of the classes and cannot automatically adapt to the frequently changing network traffic trends. This emphasizes the need for the development of new DDoS detection mechanisms that target zero-day and sophisticated DDoS attacks. To fulfill this need, an online sequential DDoS detection scheme that is suitable for use with multivariate data was proposed. The proposed algorithm utilizes a kernel-based learning algorithm, the Mahalanobis distance, and a chi-square test. The algorithm is fully automated and does not require a pre-defined setting of any thresholds or baseline normal network traffic for training. Initially, four entropy-based and four statistical features were extracted from network flows as detection metrics per minute. Then, the kernel-based learning algorithm was employed to detect entropy-based input feature vectors that were suspected to be DDoS. This algorithm assumes no model for network traffic or DDoS; then, it constructs and adapts a Dictionary of features that approximately span the subspace of normal behavior. Every T minutes, the Mahalanobis distance between suspicious vectors and the distribution of Dictionary members is measured. Subsequently, the chi-square test is used to evaluate the Mahalanobis distance. The proposed DDoS detection scheme was applied to the CICIDS2017 dataset and the performance of the algorithm was measured using different performance metrics including accuracy, recall, precision and ROC-Curve. Finally, the results were compared with those by existing algorithms. It was demonstrated that the proposed online detection scheme outperforms almost all available DDoS classification algorithms with an offline learning process.

Announcement Category

Ali Mert Ertuğrul, Interpretable Spatio-Temporal Networks for Modeling and Forecasting Societal Events

PhD Candidate: Ali Mert Ertuğrul
Program: Information Systems
Date: 20.11.2019 15:30
Place: Conference Hall 1

Abstract: The relationships between individual activities and societal events (e.g. migrations, social movements) are complex due to the various social, temporal and spatial factors. Understanding such relationships in the context of various societal events such as street protests and opioid crisis, and forecasting these events is important as they have great impacts on public policies and supporting decision making of authorities. In this thesis, novel, spatio-temporal, deep neural networks are proposed (i) to forecast societal events and (ii) to help examine the relationships between societal events and their social and geographical contexts. The proposed models are designed to model the complex interactions between local (observed from within a location) and global (observed from all locations) activities by incorporating a new design of attentional networks. They are capable of forecasting the occurrence of future societal events and allow for interpreting what features, from which places, and how they contribute to event forecasting. Within the scope of this thesis, extensive experiments are conducted to evaluate the proposed networks on two different types of population-level societal events, namely social movements and opioid overdoses, with multiple datasets. The results indicate that the proposed models achieve superior forecasting performance than the compared methods. Also, they provide meaningful interpretations in terms of (i) what local and global activity features are more predictive, (ii) what locations have more salient contributions, and (iii) how these locations contribute to forecasting the subsequent events.

Announcement Category

Sarper Alkan, A computational model of the brain for decoding mental states from fMRI

In this study we present a brain model for decoding mental states that are captured using functional brain imaging (fMRI). We postulate that, the human brain processes information coming from the senses using specialized brain regions and the brain combines the activity of the specialized regions to come up with a coherent mental state. We model the postulated pattern of information processing in the brain as follows: First, we propose to capture the activity of specialized brain regions using homogenous voxel (volumetric pixel) groups: Supervoxels. Second, we combine the activity of supervoxels to decode the overall mental state using classifier ensembles: Brain Region Ensembles (BRE).

We test our model in three distinct fMRI datasets, where our model performs better, in terms of accuracy of classification of mental states, than the widely used brain decoding methods that rely on voxel selection. Also, we present how supervoxels can be used for the localization of the brain regions that are effective in discriminating the mental states under consideration regarding fMRI experiments.

Date: 07.10.2019 14:30 Place: Conference Hall 1

Sarper Alkan, A computational model of the brain for decoding mental states from fMRI

English

Siber Güvenlik EABD Tezsiz Yüksek Lisans Programı 2.Grup Mülakat Sonuçları

Siber Güvenlik EABD Tezsiz Yüksek Lisans Programı 2.Grup Mülakat Sonuçları

Siber Güvenlik EABD Tezsiz Yüksek Lisans Programına, 2019-2020 Eğitim Öğretim Yılı sonbahar dönemi için, 2.Grup başvurularına ait yapılan mülakatlar neticesinde programa kabul edilen öğrencilerin isimleri aşağıda belirtilmiştir.

* Programa yeni kabul edilen öğrencilerimizle ayrıca, 18 Eylül 2019 saat 10:00'da oryantasyon toplantısı yapılacak olup, web sayfamız üzerinden toplantı tarih ve saat bilgileri yayınlanacaktır.

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