Bilgisayar Mühendisliği Bölümü

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Citation - WoS: 7
Citation - Scopus: 10
A literature survey: Is it necessary to develop a new software development methodology for virtual reality projects?
(Graz Univ Technolgoy, inst information Systems Computer Media-iicm, 2017) Güleç, Ulaş; Gulec, Ulas; Yilmaz, Murat; Yılmaz, Murat; Isler, Veysi; 47439; Bilgisayar Mühendisliği; Yazılım Mühendisliği
Software development is a complex human endeavour with high failure rates. Although a variety of software development methodologies have been proposed to improve the software development process, there is no universal model for all software development organizations. Virtual reality (VR) is an emerging trend especially for the gaming industry, which should prepare itself for VR development. The goal of this study is to explore potential software development activities and determine whether designing a new software development methodology for VR projects is an important topic for software development organizations working on VR software development. For this purpose, a literature survey has been completed and 71 academic studies have been examined in detail. This study shows that no work is being conducted in the field of developing a new methodology for VR projects. However, the study does show that there are similar endeavours in the field of human computer interaction (HCI), such as game development methodology.
Citation - WoS: 3
Citation - Scopus: 4
Automatic Coastline Detection Using Image Enhancement and Segmentation Algorithms
(Hard, 2016) Maras, Erdem Emin; Maraş, Hadi Hakan; Caniberk, Mustafa; Maras, Hadi Hakan; 34410; Bilgisayar Mühendisliği
Coastlines have hosted numerous civilizations since the earliest times of mankind due to the advantages they offer such as natural resources, transportation, arable areas, seafood, trade, and biodiversity. Coastal regions should be monitored vigilantly by planners and control mechanisms, and any changes in these regions should be detected with its human or natural origin, and future plans and possible interventions should be formed in these aspects to maintain ecological balance, sustainable development, and planned urbanization. Integrated coastal zone management (ICZM) provides an important tool to reach that goal. One of the important elements of ICZM is the detection of coastlines. While there are several methods to detect coastlines, remote sensing methods provide the fastest and the most efficient solutions. In this study, color infrared, grayscale, RGB, and fake infrared images were processed with the median filtering and segmentation software developed within the study, and coastal lines were detected by the edge detection method. The results show that segmentation with fake infrared images derived from RGB images give the best results.
Citation - WoS: 3
Citation - Scopus: 4
Block size analysis for discrete wavelet watermarking and embedding a vector image as a watermark
(Zarka Private Univ, 2019) Sever, Hayri; Sever, Hayri; Senol, Ahmet; Elbasi, Ersin; 11916; Bilgisayar Mühendisliği
As telecommunication and computer technologies proliferate, most data are stored and transferred in digital format. Content owners, therefore, are searching for new technologies to protect copyrighted products in digital form. Image watermarking emerged as a technique for protecting image copyrights. Early studies on image watermarking used the pixel domain whereas modern watermarking methods convert a pixel based image to another domain and embed a watermark in the transform domain. This study aims to use, Block Discrete Wavelet Transform (BDWT) as the transform domain for embedding and extracting watermarks. This study consists of 2 parts. The first part investigates the effect of dividing an image into non overlapping blocks and transforming each image block to a DWT domain, independently. Then, effect of block size on watermark success and, how it is related to block size, are analyzed. The second part investigates embedding a vector image logo as a watermark. Vector images consist of geometric objects such as lines, circles and splines. Unlike pixel-based images, vector images do not lose quality due to scaling. Vector watermarks deteriorate very easily if the watermarked image is processed, such as compression or filtering. Special care must be taken when the embedded watermark is a vector image, such as adjusting the watermark strength or distributing the watermark data into the image. The relative importance of watermark data must be taken into account. To the best of our knowledge this study is the first to use a vector image as a watermark embedded in a host image.
Citation - WoS: 0
Citation - Scopus: 0
Classification of Linked Data Sources Using Semantic Scoring
(Ieice-inst Electronics information Communication Engineers, 2018) Yumusak, Semih; Doğdu, Erdoğan; Dogdu, Erdogan; Kodaz, Halife; 142876; Bilgisayar Mühendisliği
Linked data sets are created using semantic Web technologies and they are usually big and the number of such datasets is growing. The query execution is therefore costly, and knowing the content of data in such datasets should help in targeted querying. Our aim in this paper is to classify linked data sets by their knowledge content. Earlier projects such as LOD Cloud, LODStats, and SPARQLES analyze linked data sources in terms of content, availability and infrastructure. In these projects, linked data sets are classified and tagged principally using VoID vocabulary and analyzed according to their content, availability and infrastructure. Although all linked data sources listed in these projects appear to be classified or tagged, there are a limited number of studies on automated tagging and classification of newly arriving linked data sets. Here, we focus on automated classification of linked data sets using semantic scoring methods. We have collected the SPARQL endpoints of 1,328 unique linked datasets from Datahub, LOD Cloud, LODStats, SPARQLES, and SpEnD projects. We have then queried textual descriptions of resources in these data sets using their rdfs: comment and rdfs: label property values. We analyzed these texts in a similar manner with document analysis techniques by assuming every SPARQL endpoint as a separate document. In this regard, we have used WordNet semantic relations library combined with an adapted term frequency-inverted document frequency (tfidf) analysis on the words and their semantic neighbours. In WordNet database, we have extracted information about comment/label objects in linked data sources by using hypernym, hyponym, homonym, meronym, region, topic and usage semantic relations. We obtained some significant results on hypernym and topic semantic relations; we can find words that identify data sets and this can be used in automatic classification and tagging of linked data sources. By using these words, we experimented different classifiers with different scoring methods, which results in better classification accuracy results.
Citation - WoS: 15
Citation - Scopus: 19
Deep learning methods in the diagnosis of sacroiliitis from plain pelvic radiographs
(Oxford Univ Press, 2023) Ureten, Kemal; Maras, Yuksel; Duran, Semra; Gok, Kevser
Objectives The aim of this study is to develop a computer-aided diagnosis method to assist physicians in evaluating sacroiliac radiographs. Methods Convolutional neural networks, a deep learning method, were used in this retrospective study. Transfer learning was implemented with pre-trained VGG-16, ResNet-101 and Inception-v3 networks. Normal pelvic radiographs (n = 290) and pelvic radiographs with sacroiliitis (n = 295) were used for the training of networks. Results The training results were evaluated with the criteria of accuracy, sensitivity, specificity and precision calculated from the confusion matrix and AUC (area under the ROC curve) calculated from ROC (receiver operating characteristic) curve. Pre-trained VGG-16 model revealed accuracy, sensitivity, specificity, precision and AUC figures of 89.9%, 90.9%, 88.9%, 88.9% and 0.96 with test images, respectively. These results were 84.3%, 91.9%, 78.8%, 75.6 and 0.92 with pre-trained ResNet-101, and 82.0%, 79.6%, 85.0%, 86.7% and 0.90 with pre-trained inception-v3, respectively. Conclusions Successful results were obtained with all three models in this study where transfer learning was applied with pre-trained VGG-16, ResNet-101 and Inception-v3 networks. This method can assist clinicians in the diagnosis of sacroiliitis, provide them with a second objective interpretation and also reduce the need for advanced imaging methods such as magnetic resonance imaging.
Citation - WoS: 30
Density functional study of physical and chemical properties of nano size Boron Clusters: B-n (n=13-20)
(Chinese Physical Soc, 2009) Atis, Murat; Özdoğan, Cem; Ozdogan, Cem; Guvenc, Ziya B.; 28225; Ortak Dersler Bölümü
Boron is an element that has ability to build strong and highly directional bonds with boron itself. As a result, boron atoms form diverse structural motifs, ultimately can yield distinct nano structures, such as planar, quasi-planar, convex, cage, open-cage, tubular, spherical., ring, dome-like, shell, capsule, and so on, i.e., it can take almost any shape. Therefore, a deep understanding of the physical and chemical properties becomes important in boron cluster chemistry. Electronic and geometric structures, total and binding energies, harmonic frequencies, point symmetries, charge distributions, dipole moments, chemical bondings and the highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps of neutral B-n (n=13-20) clusters have been investigated by, density functional theory (DFT), B3LYP with 6-311++G(d,p) basis set. Furthermore, the first and the second energy differences are used to obtain the most stable sizes. We have observed that almost all physical properties are size dependent, and double-ring tubular form of B-20 has the highest binding energy per atom. The icosahedral structure with an inside atom is found as impossible as a stable structure for the size thirteen. This structure transforms to an open-cage form. The structural transition from two-dimensional to three-dimensional is found at the size of 20 and consistent with the literature. The calculated charges by the Mulliken analysis show that there is a symmetry pattern with respect to the x-z and y-z planes for the charge distributions. The unusual planar stability of the boron clusters may be explained by the delocalized pi and sigma bonding characteristic together with the existence of the multicentered bonding. The results have been compared to available studies in the literature.
Citation - WoS: 21
Citation - Scopus: 27
Effective Social Productivity Measurements during Software Development: An Empirical Study
(World Scientific Publ Co Pte Ltd, 2016) Yilmaz, Murat; Yılmaz, Murat; O'Connor, Rory V.; Clarke, Paul; Yazılım Mühendisliği
Much of contemporary scientific discussion regarding factors that influence software development productivity is undertaken in various domains where there is an insuflcient empirical basis for exploring socio-technical factors of productivity that are specific to a software development organization. The purpose of the study is to characterize the multidimensional nature of software development productivity and its social aspects as a set of latent constructs (i.e. variables that are not directly observed) for a medium-sized software company. To this end, we designed an exploratory in-depthfield study based on the hypothesized productivity constructs, which were modeled by a set of factors identified from literature reviews, and later refined by industrial focus groups. In order to demonstrate the applicability of our approach, we conducted confirmatory factor analysis with the data attained from a questionnaire with 216 participants. To investigate factors of influence further, we analyzed the impact of selected team-based variables over the latent constructs of productivity. Taken together, our findings confirm that such an approach can be used to explore the quantifiable influence of socio-technical factors that would affect productivity of a particular software development organization. Ultimately, the resulting model provides guidance to explore the comparative importance of a set of firm-specific factors that may help to improve the productivity of the organization.
Citation - WoS: 0
Citation - Scopus: 3
Experimental study on the sensitivity of autocalibration to projective camera model parameters
(Spie-soc Photo-optical instrumentation Engineers, 2006) Hassanpour, Reza; Hassanpour, Reza; Atalay, Volkan; 48646; Yazılım Mühendisliği
Existing methods of 3-D object modeling and recovering 3-D data from uncalibrated 2-D images are subject to errors introduced by assumptions about camera parameters and mismatches in finding point pairs in the images. In this study, we experimentally evaluate the effect of each of these assumptions together with the inaccuracy in the measurements in the images. Sensitivity of reconstruction errors to inaccuracies in the estimation of camera parameters and mismatches due to noise in input data is measured using a linear and two nonlinear autocalibration methods for a projective camera. Our experimental results show that some assumptions such as a vanishing skew can be safely made; however, other parameters such as principal point location are quite sensitive to wrong assumptions. (c) 2006 Society of Photo-Optical Instrumentation Engineers.
Citation - WoS: 5
Citation - Scopus: 6
Exploring the Belief Systems of Software Development Professionals
(Taylor & Francis inc, 2015) O'Connor, Rory V.; Yilmaz, Murat
It is commonly accepted that an individual's beliefs and actions are based on his or her assessment and perceptions of the world. In order to determine what practices an individual is likely to follow at any given time, it is necessary to understand the individual's behavioral intention in a given circumstance. From an Information Technology perspective, a software development professional's belief systems are potentially the basis for the adoption and implementation of new and innovative work practices and processes. In this article, we explore the belief systems of software development professionals in order to understand the beliefs underlying intention and practice, and we seek answers about how they adopt or reject new and innovative software development processes and practices. The results point out a strong influence of past experiences, personality types, and repeated behavior on current software development processes and practices in industrial settings.
Citation - WoS: 7
Citation - Scopus: 10
Extending a sentiment lexicon with synonym-antonym datasets: SWNetTR plus
(Tubitak Scientific & Technological Research Council Turkey, 2019) Saglam, Fatih; Sever, Hayri; Genc, Burkay; Sever, Hayri; 11916; Bilgisayar Mühendisliği
In our previous studies on developing a general-purpose Turkish sentiment lexicon, we constructed SWNetTR-PLUS, a sentiment lexicon of 37K words. In this paper, we show how to use Turkish synonym and antonym word pairs to extend SWNetTR-PLUS by almost 33% to obtain SWNetTR++, a Turkish sentiment lexicon of 49K words. The extension was done by transferring the problem into the graph domain, where nodes are words, and edges are synonym- antonym relations between words, and propagating the existing tone and polarity scores to the newly added words using an algorithm we have developed. We tested the existing and new lexicons using a manually labeled Turkish news media corpus of 500 news texts. The results show that our method yielded a significantly more accurate lexicon than SWNetTR-PLUS, resulting in an accuracy increase from 72.2% to 80.4%. At this level, we have now maximized the accuracy rates of translation-based sentiment analysis approaches, which first translate a Turkish text to English and then do the analysis using English sentiment lexicons.
Citation - WoS: 43
Citation - Scopus: 53
Gamification as a disruptive factor in software processimprovement initiatives
(Graz Univ Technolgoy, inst information Systems Computer Media-iicm, 2014) Herranz, Eduardo; Yılmaz, Murat; Colomo-Palacios, Ricardo; de Amescua Seco, Antonio; Yilmaz, Murat; Yazılım Mühendisliği
For any Software Process Improvement (SPI) initiative to succeed human factors, in particular, motivation and commitment of the people involved should be kept in mind. In fact, Organizational Change Management (OCM) has been identified as an essential knowledge area for any SPI initiative. However, enough attention is still not given to the human factors and therefore, the high degree of failures in the SPI initiatives is directly linked to a lack of commitment and motivation. Gamification discipline allows us to define mechanisms that drive people's motivation and commitment towards the development of tasks in order to encourage and accelerate the acceptance of an SPI initiative. In this paper, a gamification framework oriented to both organization needs and software practitioners groups involved in an SPI initiative is defined. This framework tries to take advantage of the transverse nature of gamification in order to apply its Critical Success Factors (CSF) to the organizational change management of an SPI. Gamification framework guidelines have been validated by some qualitative methods. Results show some limitations that threaten the reliability of this validation. These require further empirical validation of a software organization.
Citation - WoS: 6
Citation - Scopus: 6
Illicit Material Detection using Dual-Energy X-Ray Images
(Zarka Private Univ, 2016) Hassanpour, Reza; Hassanpour, Reza; Yazılım Mühendisliği
Dual energy X-ray inspection systems are widely used in security and controlling systems. The performance of these systems however, degrades with the poor performance of human operators. Computer vision based systems are of vital importance in improving the detection rate of illicit materials, while keeping false alarms at a reasonably low level. In this study, a novel method is proposed for detecting material overlapping and reconstructing multiple images by alleviating these overlaps. Evaluation tests were conducted on images taken from luggage inspection X-ray screening devices used in shopping centres. The experimental results indicate that the reconstructed images are much easier to inspect by human operators than the unprocessed original images.
Citation - WoS: 2
Citation - Scopus: 2
Improvement of DWT-SVD with Curve Fitting and Robust Regression: An Application to Astronomy Images
(Kaunas Univ Technology, 2016) Karadeniz, Talha; Karadeniz, Talha; Elbasi, Ersin; 304886; Yazılım Mühendisliği
DWT-SVD is a frequency domain based eigenanalysis watermarking technique. In this work, we improve this method by exploring the relationship between the cover image's DWT singular values and those of the watermark. We show that, via the usage of curve fitting and robust regression, it is possible to achieve accurate results. We also demonstrate that the improved scheme is suitable for the watermarking of astronomy images. In addition to encoding and decoding examples, statistical results on stealth and robustness are deduced from the experiments so that the clear advance can be observed. Quality of the watermark is measured by testing against various attack types.
Citation - WoS: 3
Citation - Scopus: 4
Improving Social Aspects of the Software Development Process: Games, Gamification and Related Approaches
(Graz Univ Technolgoy, inst information Systems Computer Media-iicm, 2016) Yilmaz, Murat; Yılmaz, Murat; O'Connor, Rory V.; Mora, Manuel; Yazılım Mühendisliği
Citation - WoS: 2
Citation - Scopus: 3
Investigating the Relationship Between SLOC and Logical Database Measures to Improve the Early Estimation of Software Cost
(World Scientific Publ Co Pte Ltd, 2019) Tokdemir, Gul; Tokdemir, Gül; Cagiltay, Nergiz Ercil; 17411; Bilgisayar Mühendisliği
Project planning is a critical activity in the software development life cycle. At the early stages of a project, the managers need to estimate required time, effort and cost to plan, track and then to deliver the project successfully. Many studies have attempted to provide methods for precise software cost estimation. The current software cost estimation methods are mainly based on software size estimation and functional system requirements. The main assumption of this study is that, as the primary source of complexity in today's software is the interaction between the database and the user, database measures may provide inputs allowing current software estimation methods to achieve more accurate results. Accordingly, this study attempts to gain insights from objective measures, collected through the logical database model of software systems, for better prediction of the software's effort and hence cost through software lines of code (SLOC) measure. For this purpose, more than 2.5 million lines of code developed by four different companies, for 79 different software packages with their related database design measures, are analyzed. The results of this study show that there is a close correlation between the software size and database design measure, namely, the number of tables which can be collected at the logical database design stage. By adapting this result, the current estimation models could be improved significantly.
Citation - WoS: 0
MM-FOOD: a high-dimensional index structure for efficiently querying content and concept of multimedia data
(Ios Press, 2023) Arslan, Serdar; Arslan, Serdar; Yazici, Adnan; 325411; Bilgisayar Mühendisliği
The semantic query problem is commonly called the semantic gap and is one of the significant problems in multimedia data retrieval. In this study, we focus on multimedia data retrieval by combining semantic information with data content to solve the semantic gap problem effectively. The main idea behind the combination of low-level content descriptors and the concept of multimedia data is to represent the content information with the semantic information by adding a low-level content descriptor as a new dimension to the index structure. This new dimension is represented by constructing an array index structure that uses a fuzzy clustering algorithm. Thus, a new high-dimensional index structure, named MM-FOOD, supporting querying of multimedia data, including fuzzy querying, is presented in this paper. This proposed index structures construction and query algorithms are explained throughout this paper. Our experiments show that our indexing mechanism is considerably efficient compared to the basic indexing approach, which stores low-level content and semantic concept descriptors in separate structures when the data size is large.
Citation - WoS: 8
Citation - Scopus: 9
Power Aware Routing Protocols in Wireless Sensor Network
(Ieice-inst Electronics information Communications Eng, 2016) Alsultan, Mohammed; Hassanpour, Reza; Oztoprak, Kasim; Hassanpour, Reza; Yazılım Mühendisliği
Wireless Sensor Networks (WSNs) have gained importance with a rapid growth in their applications during the past decades. There has also been a rise in the need for energy-efficient and scalable routing along with the data aggregation protocols for the large scale deployments of sensor networks. The traditional routing algorithms suffer from drawbacks such as the presence of one hop long distance data transmissions, very large or very small clusters within a network at the same moment, over-accumulated energy consumption within the cluster-heads (CHs) etc. The lifetime of WSNs is also decreased due to these drawbacks. To overcome them, we have proposed a new method for the Multi Hop, Far-Zone and Load-Balancing Hierarchical-Based Routing Algorithm for Wireless Sensor Network (MFLHA). Various improvements have been brought forward by MFLHA. The first contribution of the proposed method is the existence of a large probability for the nodes with higher energy to become the CH through the introduction of the energy decision condition and energy-weighted factor within the electing threshold of the CH. Secondly, MFLHA forms a Far-Zone, which is defined as a locus where the sensors can reach the CH with an energy less than a threshold. Finally, the energy consumption by CHs is reduced by the introduction of a minimum energy cost method called the Multi-Hop Inter-Cluster routing algorithm. Our experimental results indicate that MFLHA has the ability to balance the network energy consumption effectively as well as extend the lifetime of the networks. The proposed method outperforms the competitors especially in the middle range distances.
Citation - WoS: 1
Citation - Scopus: 1
Relative consistency of projective reconstructions obtained from the same image pair
(World Scientific Publ Co Pte Ltd, 2006) Otlu, Burcak; Hassanpour, Reza; Atalay, M. Volkan; Hassanpour, Reza; 163907; 48646; Yazılım Mühendisliği
This study obtains projective reconstructions of an object or a scene from its image pair and measures relative consistency of these projective reconstructions. 3D points are estimated from an image pair using projective and epipolar geometry. Two measures are presented for verification of projective reconstructions with each other. These measures are based on the equality of ratios between the x-, y- and z-coordinates of 3D reconstructed points which are obtained from the same corresponding points. This information is used for measuring the relative consistency of projective reconstructions obtained from the same image pair.
Citation - WoS: 48
Citation - Scopus: 63
Software Engineering Education and Games: A Systematic Literature Review
(Graz Univ Technolgoy, inst information Systems Computer Media-iicm, 2016) Kosa, Mehmet; Yılmaz, Murat; Yilmaz, Murat; O'Connor, Rory V.; Clarke, Paul M.; Yazılım Mühendisliği
The trend in using games in elementary level education also spreads through higher education levels and specific domains such as engineering. Recently, researchers have shown an increased interest in the usage of games in software engineering. In this paper, we are presenting a systematic review and analysis of 350 papers regarding games in software engineering education that was published in the last fifteen years. After applying our inclusion criteria and manual inspection of these studies, we have ended up with 53 primary papers. Based on a systematic process, we reported and discussed our findings with possible future research directions. The main results of this study indicate that the studies are accumulated around 5 categories: Games that learners/students play, games that learners/students develop as projects, curriculum proposals, developing/coming up with new approaches, tools, frameworks or suggestions and others.
Citation - WoS: 1
Unbalanced Multiple Description Wavelet Coding for Scalable Video Transmission
(Spie-soc Photo-optical instrumentation Engineers, 2012) Choupani, Roya; Wong, Stephan; Tolun, Mehmet; 21259
Scalable video coding and multiple description coding are the two different adaptation schemes for video transmission over heterogeneous and best-effort networks such as the Internet. We propose a new method to encode video for unreliable networks with rate adaptation capability. Our proposed method groups three dimensional discrete wavelet transform coefficients in different descriptions and applies a modified embedded zero tree data for rate adaptation. The proposed method optimizes the bit-rates of the descriptions with respect to the channel bit rates and the maximum acceptable distortion. The experimental results in the presence of one description loss indicate that on average the videos at the rate of 1000 Kbit/s are reconstructed with Y-component of peak signal to noise ratio (Y-PSNR) value of 36.2 dB. The dynamic allocation of descriptions to the network channels is optimized for rate distortion minimization. The improvement in term of Y-PSNR achieved by rate distortion optimization has been between 0.7 and 5.3 dB in different bit rates. (c) 2012 SPIE and IS&T. [DOI: 10.1117/1.JEI.21.4.043006]

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