Ahmet Selman Bozkir

Hacettepe University · Department of Computer Engineering

There has been ever-growing use of Internet and progress within many communication channels such as social media and this escalates the need for rapid and low-source demanding phishing detection mechanisms. In this very study, we propose a new deep neural model for phishing URL identification so-called GramBeddings introducing some distinguishing n...

Visual impairment significantly challenges daily life, limiting mobility and independence. Traditional devices such as canes have provided limited detection capabilities, and the applications developed have yet to give the desired mobility and reliability. In this work, we aim to solve the problems of visually impaired individuals using image proce...

Phishing attacks are still seen as a significant threat to cyber security, and large parts of the industry rely on anti-phishing simulations to minimize the risk imposed by such attacks. This study conducted a large-scale anti-phishing training with more than 31000 participants and 144 different simulated phishing attacks to develop a data-driven m...

With the spread of COVID-19 over the world, the need arose for fast and precise automatic triage mechanisms to decelerate the spread of the disease by reducing human efforts e.g. for image-based diagnosis. Although the literature has shown promising efforts in this direction, reported results do not consider the variability of CT scans acquired und...

The everlasting increase in usage of information systems and online services have triggered the birth of the new type of malware which are more dangerous and hard to detect. In particular, according to the recent reports, the new type of fileless malware infect the victims’ devices without a persistent trace (i.e. file) on hard drives. Moreover, ex...

Recent years of object detection (OD), a fundamental task in computer vision, have witnessed the rise of numerous practical applications of this sub-field such as face detection, self-driving, security, and more. Although existing deep learning models show significant achievement in object detection, they are usually tested on datasets having mostl...

In this study, we propose a novel methodology in order to predict Geological Strength Index (GSI) values of rock outcrops by using computer vision and machine learning methods. For this purpose, we separately employed two different global image descriptors namely GIST and HOG (Histogram of Oriented Gradients) to extract a discriminative and "holist...

Educational data mining is a developing research trend for exploring hidden patterns and natural associations among a set of student, teacher or school related variables. Discovering profiles of preservice science teachers using data mining methods would give important information about quality of teacher education programs and future science teach...

With the advent of Internet and opportunities in e-commerce, a visual perception oriented cyber-attack so-called phishing has become one of the tremendous problems of the cyber world since it aims to access user credentials in order to gain illegal financial profit and steal sensitive personal data. In order to fight with this security threat, vari...

CryptoWalls ranks first among the Ransomware in terms of its design, objectives, and damages. Cybercriminals use CryptoWalls in a wide range of applications, from crosscountry cyberterrorism to demanding ransom from an ordinary Internet user. Despite all the measures taken, an effective protection against CryptoWalls has still not been developed. T...

The main purpose of this book chapter is to develop a computer vision based approach which is able to calculate approximate Geological Strength Index (GSI) value of rock mass when the photograph of rock outcrop is given to the computer. For this purpose, local image descriptors Scale Invariant Feature Transform (SIFT) and DAISY and machine learning...

With the advent of e-commerce, digital services and social media, scammers have changed their way to gain illegal benefits in various forms such as capturing the credit card information or exploiting personal cloud accounts which is termed as phishing. For this reason, against this cyber crime, last two decades have witnessed a variety of combattin...

Phishing attacks, which have exponentially increased in recent years, are a form of cyber attack aiming to steal sensitive credentials of innocent users. In general, the attackers attempt to deceive users by creating and submitting a fake but visually similar version of a legitimate web page, which has already been in usage. In this study, we sugge...

Phishing attacks, which have exponentially increased in recent years with the development of Internet, are a form of cyber attack aiming to steal sensitive credentials of innocent users. In general, the attackers attempt to deceive users by creating and submitting a fake but visually similar version of a legitimate web page, which has already been...

With the advent of e-commerce, digital services and social media, scammers have changed their way to gain illegal benefits in various forms such as capturing the credit card information or exploiting personal cloud accounts which is termed as phishing. For this reason, against this cyber crime, last two decades have witnessed a variety of combattin...

This study aims to determine the overt and covert patterns that teachers’ and prospective teachers’ views on the use of information and communication technology (ICT) instruments contain by using the method of data mining. The study group was composed of 192 prospective teachers attending a state university in Ankara, Turkey and 101 teachers workin...

Advances in Industry 4.0, IoT and mobile systems have led to an increase in the number of malware threats that target these systems. The research shows that classification via the use of computer vision and machine learning methods over byte-level images extracted from malware files could be an effective static solution. In this study, in order to...

Phishing, a continuously growing cyber threat, aims to obtain innocent users' credentials by deceiving them via presenting fake web pages which mimic their legitimate targets. To date, various attempts have been carried out in order to detect phishing pages. In this study, we treat the problem of phishing web page identification as an image classif...

In this paper, we propose a ranking approach which considers visual similarities among web pages by using structure and vision-based features. Throughout the study, we aim to understand and represent the web page visual structure as in the way people do by focusing on the layout similarity through the wireframe design. The conducted study is compos...

With the advent of the Internet and reduction of the costs in digital communication, spam has become a key problem in several types of media (i.e. email, social media and micro blog). Further, in recent years, email spamming in particular has been subjected to an exponentially growing threat which affects both individuals and business world. Hence,...

Yirmi birinci yüzyıl becerileri arasında yer alan teknoloji kullanma becerisi gün geçtikçe daha önemli hale gelmektedir (P21,2017). Günlük yaşamda karşılaştığımız problemleri çözebilen, derinlemesine düşünen yenilikçiler, araştırmacılar, eğitimciler ve liderlerin yetiştirilmesinde fen, matematik gibi disiplinlerin yanı sıra teknolojiyi kullanma bec...

Phishing is a scamming activity which deals with making a visual illusion on computer users by providing fake web pages which mimic their legitimate targets in order to steal valuable digital data such as credit card information or e-mail passwords. In contrast to other anti-phishing attempts this paper proposes to evaluate and solve this problem b...

The purpose of this article is to identify the order of significance of the variables that affect science and mathematics achievement in middle school students. For this aim, the study deals with the relationship between science and math in terms of different angles using the perspectives of multiple causes-single effect and of multiple causes-mult...

Web page visual similarity has been a trend topic in last decade. Furthermore , effective methods and approaches are crucial for phishing detection and related issues. In this study, we aim to develop a search engine for web page visual similarity and propose a novel method for capturing and calculating layout similarity of web pages. To achieve th...

Class imbalance problem in data, plays a critical role in use of machine learning methods for text classification since feature selection methods expect homogeneous distribution as well as machine learning methods. This study investigates two different kinds of feature selection metrics (one-sided and two-sided) as a global component of term weight...

The uncertainty of consumption demand in institutional food courts can cause loses of resources, work power and prestige. In this study, to overcome this problem, decision tree, a predictive data mining method was utilized. Thus, decision tree models sourced from an original 44 monthly dataset were generated and a tool named ADEM was designed and d...

The current DSS tools are generally built as “desktop applications” and designed for the use of data mining experts. In this paper, design and implementation of ASMINER, a new web-based data mining exploration and reporting tool, is introduced. ASMINER enables both decision makers and also knowledge workers, exploring and reporting with three data...

The aim of this study is to determine the convenience of Sutton's game-theoretic sunk cost theory by profiling Turkish manufacturing industries via fuzzy c-means (FCM) and expectation-maximisation (EM) clustering methods. The effects of sunk costs on market structure are analysed separately for exogenous and endogenous sunk cost industries in Turki...

In recent years, with the increase of industrial production, assessment of the physical consequences of human and production activities became crucial in terms of efficient and environment friendly production. At this point, certain methods such as Energy Material Flow Analyses (EMFA) and Life Cycle Assessment (LCA), which contribute to optimizatio...

ERP (Enterprise Resource Planning) softwares are the advanced solutions which tailored for whole enterprise needs and target high efficiency in production & service issues. In this study, the benefits of ERP upgrading in enterprises and the required infrastructural issues prior to this upgrading are revealed by descriptive data mining methods. For...

Fluctuations and unpredictability in food demand generally cause problems in economic point of view in public food courts. In this study, to overcome this problem and predict actual consumption demand for a specified menu in a selected date, three decision tree methods (CART, CHAID and Microsoft Decision Trees) are utilized. A two year period datas...

In recent years, mobile devices have developed significantly in terms of technical capabilities, computing power, storage capacity and ability of sensing different activities via intelligent built-in sensors. In this perspective, capabilities of ultimate mobile phone technology has begun to be a candidate novel platform for machine learning and dat...

Currently, social networks such as Facebook or Twitter are getting more and more popular due to the opportunities they offer. As of November 2009, Facebook was the most popular and well known social network throughout the world with over 316 million users. Among the countries, Turkey is in third place in terms of Facebook users and half of them are...

In recent years, many companies have begun to use data mining and decision support systems (DSS) for decision making activities. Although their use is increasing continuously, DSSs are generally built as "desktop applications" and designed for the use of data mining experts. The purposes of the present study are selected as design and implementatio...

Bu çalışmada karar ağacı derinliklerinin CART algoritmasının kestirim kapasitesine etkisinin incelenmesi amaçlanmıştır. Ayrıca, kaya mühendisliğinde karar ağaçlarının kestirim amaçlı kullanılabilirliği araştırılmıştır. Çalışmanın amacına uygun olarak bir tünel açma makinesinin ilerleme performansı verileri kullanılmıştır. Yapılan değerlendirme sonu...

The landslides are accepted as one of the important natural hazards throughout the world. Besides, the regional landslide susceptibility assessments is one of the first stages of the landslide hazard mitigation efforts. For this purpose, various methods have been applied to produce landslide susceptibility maps for many years. However, application...

The main purpose of the present study is to investigate the possible application of decision tree in landslide susceptibility assessment. The study area having a surface area of 174.8 km2 locates at the northern coast of the Sea of Marmara and western part of Istanbul metropolitan area. When applying data mining and extracting decision tree, geolog...

In this study, the data, which include daily food lists and sales records of 2008 that are belonged to refectories of Hacettepe University at Beytepe Campus, are analyzed via two data mining techniques (decision trees and association rules). By this way, the patterns and important factors that affect the amount of consumption are tried to be determ...

As is known, in our country, Student Selection Exam (ÖSS) is applied by Student Selection and Placement Center (ÖSYM) in every June. Over one and half million students take this exam every year. According to the results of this examination, the students who are possible to attend both the universities in Turkey and the other countries are determine...

Some detrimental effects resulting from landslides on human life and economy of many nations are observed throughout the world. Owing to these effects of landslides, landslide susceptibility evaluation is one of the hot topics in international landslide literature. Various methods such as simple overlay, bivariate and multivariate statistics, fuzzy...