Bilgisayar Mühendisliği Bölümü Yayın Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/253

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Citation - WoS: 33
Citation - Scopus: 43
A 3d Virtual Environment for Training Soccer Referees
(Elsevier Science Bv, 2019) Isler, Veysi; O'Connor, Rory V.; Clarke, Paul M.; Gulec, Ulas; Yilmaz, Murat
Emerging digital technologies are being used in many ways by and in particular virtual environments provide new opportunities to gain experience on real-world phenomena without having to live the actual real-world experiences. In this study, a quantitative research approach supported by expert validation interviews was conducted to determine the availability of virtual environments in the training of soccer referees. The aim is to design a virtual environment for training purposes, representing a real-life soccer stadium to allow the referees to manage matches in an atmosphere similar to the real stadium atmosphere. At this point, the referees have a chance to reduce the number of errors that they make in real life by experiencing difficult decisions that they encounter during the actual match via using the virtual stadium. In addition, the decisions and reactions of the referees during the virtual match were observed with the number of different fans in the virtual stadium to understand whether the virtual stadium created a real stadium atmosphere for the referees. For this evaluation, Presence Questionnaire (PQ) and Immersive Tendencies Questionnaire (ITQ) were applied to the referees to measure their involvement levels. In addition, a semi-structure interview technique was utilized in order to understand participants' opinions about the system. These interviews show that the referees have a positive attitude towards the system since they can experience the events occurred in the match as a first person instead of watching them from camera as a third person. The findings of current study suggest that virtual environments can be used as a training tool to increase the experience levels of the soccer referees since they have an opportunity to decide about the positions without facing the real-world risks.
Citation - WoS: 4
Citation - Scopus: 5
Almost Autonomous Training of Mixtures of Principal Component Analyzers
(Elsevier Science Bv, 2004) Musa, MEM; de Ridder, D; Duin, RPW; Atalay, V
In recent years, a number of mixtures of local PCA models have been proposed. Most of these models require the user to set the number of submodels (local models) in the mixture and the dimensionality of the submodels (i.e., number of PC's) as well. To make the model free of these parameters, we propose a greedy expectation-maximization algorithm to find a suboptimal number of submodels. For a given retained variance ratio, the proposed algorithm estimates for each submodel the dimensionality that retains this given variability ratio. We test the proposed method on two different classification problems: handwritten digit recognition and 2-class ionosphere data classification. The results show that the proposed method has a good performance. (C) 2004 Elsevier B.V. All rights reserved.
Citation - WoS: 57
Citation - Scopus: 92
A Deep Neural-Network Based Stock Trading System Based on Evolutionary Optimized Technical Analysis Parameters
(Elsevier Science Bv, 2017) Ozbayoglu, Murat; Dogdu, Erdogan; Sezer, Omer Berat
In this study, we propose a stock trading system based on optimized technical analysis parameters for creating buy-sell points using genetic algorithms. The model is developed utilizing Apache Spark big data platform. The optimized parameters are then passed to a deep MLP neural network for buy-sell-hold predictions. Dow 30 stocks are chosen for model validation. Each Dow stock is trained separately using daily close prices between 1996-2016 and tested between 2007-2016. The results indicate that optimizing the technical indicator parameters not only enhances the stock trading performance but also provides a model that might be used as an alternative to Buy and Hold and other standard technical analysis models. (c) 2017 The Authors. Published by Elsevier B.V.
Citation - WoS: 23
Citation - Scopus: 24
An Investigation of Hydrogen Bonded Neutral B4hn (n=1-11) and Anionic B4h11^(-1) Clusters: Density Functional Study
(Elsevier Science Bv, 2007) Ozdogan, Cem; Guvenc, Ziya B.; Boyukata, Mustafa
In this study, detailed analysis of the structural stability of hydrogen bonded four-atom boron clusters within the framework of density functional theory (DFT) is presented. Effects of the number of hydrogen atoms on the structural stability of 134, binding energy of the clusters, and also on the boron-hydrogen binding energy are investigated. Attention is also paid to the determination of energetically the most stable geometries of B4Hn (n = 1-11) boron hydrides, and to their isomers. The lower-lying electronic states of the B4Hn structures are investigated. In addition natural electron configurations of the most stable clusters and charge transfer between the atoms in the cluster are also analyzed. Furthermore, the stability of anionic form of B4H11(-1) cluster is examined. (c) 2006 Elsevier B.V. All rights reserved.
Citation - WoS: 5
Citation - Scopus: 13
Parallel Wavelet-Based Clustering Algorithm on Gpus Using Cuda
(Elsevier Science Bv, 2011) Ozdogan, Cem; Yildirim, Ahmet Artu
There has been a substantial interest in scientific and engineering computing community to speed up the CPU-intensive tasks on graphical processing units (GPUs) with the development of many-core GPUs as having very large memory bandwidth and computational power. Cluster analysis is a widely used technique for grouping a set of objects into classes of "similar" objects and commonly used in many fields such as data mining, bioinformatics and pattern recognition. WaveCluster defines the notion of cluster as a dense region consisting of connected components in the transformed feature space. In this study, we present the implementation of WaveCluster algorithm as a novel clustering approach based on wavelet transform to GPU level parallelization and investigate the parallel performance for very large spatial datasets. The CUDA implementations of two main sub-algorithms of WaveCluster approach; namely extraction of low-frequency component from the signal using wavelet transform and connected component labeling are presented. Then, the corresponding performance evaluations are reported for each sub-algorithm. Divide and conquer approach is followed on the implementation of wavelet transform and multi-pass sliding window approach on the implementation of connected component labeling. The maximum achieved speedup is found in kernel as 107x in the computation of extraction of the low-frequency component and 6x in the computation of connected component labeling with respect to the sequential algorithms running on the CPU. (C) 2010 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of the Guest Editor.
Citation - WoS: 12
Citation - Scopus: 14
Reactions of Small Ni Clusters With a Diatomic Molecule: Md Simulation of D2+nin (n=7-10) Systems
(Elsevier Science Bv, 2000) Durmus, P; Böyükata, M; Özçelik, S; Güvenç, ZB; Jellinek, J
The kinetics of the reactions of nickel clusters with a deuterium molecule are studied, Dissociative chemisorption probabilities of the D(2) molecule on the small Ni(n) (n=7-10) clusters are computed by a quasi-classical molecular dynamics computer simulation technique. Structures of the clusters are obtained by an embedded-atom potential, and the interaction between the D(2) and Ni(n) is modelled by an LEPS (London-Eyring-Polanyi-Sato) function (energy surface). This analysis includes the chemisorption probabilities as functions of the impact parameter and of the relative translational energy of the D(2). The corresponding reactive cross-sections for the ground state of the molecule are calculated as functions of the collision energy and the size of the cluster. The role of the size of the clusters is examined. An indirect mechanism to the reaction, which involves formation of molecular adsorption as precursors to dissociative adsorption in the low collision energy region (less than 0.1eV), is observed. Results are discussed by comparing with the other similar theoretical and experimental studies. (C) 2000 Elsevier Science B.V. All rights reserved.
Citation - Scopus: 2
Software Process Improvement and Capability Determination Conference 2016
(Elsevier Science Bv, 2017) Yilmaz, Murat; Clarke, Paul
Citation - WoS: 8
Citation - Scopus: 7
Sputtering Yield and Dynamical Analysis of Ni(100) Surface: a Comparison of Four Different Ar-Surface Interaction Potentials
(Elsevier Science Bv, 2000) Güvenç, ZB; Hundur, Y; Hippler, R
The sputtering process of the Ar + Ni(100) collision system is investigated by means of constant energy molecular dynamics simulations. The Ni(100) is mimicked by an embedded-atom potential, and the interaction between the projectile and the surface is modelled by using four different screened Coulomb type potentials. The Ni atom emission from the lattice is analysed over the range of 10-40 eV collision energy. The maximum penetration depths of Ar, probability distributions of kinetic energy of the reflected Ar, and energy of the Ar and sputtered Ni atoms in the same collision events are evaluated as functions of the impact energy and sputtering time. Further, angular distributions of the scattered Ar are obtained. The calculated sputtering yields are compared with the available theoretical and experimental data. (C) 2000 Elsevier Science B.V. All rights reserved.
A Study of the Information Services on Turkish High Schools
(Elsevier Science Bv, 2011) Darvish, Hamid R.
The World Wide Web went public in 1989. Since then, every organization has come to utilize web-based technologies for their various purposes. Educational institutions have implemented web technology in their contemporary curriculums. The aim of this study is to investigate five private schools in Ankara, Turkey and to unravel the impact of information technology (internet usage, information services) in their programs. The five high schools were: Ari College, TED Ankara College, Tevfik Fikret High School, METU (Middle East Technical University) College and Bilkent High School. We conducted a qualitative research on the selected high schools by observing and collecting data. Research was done from March-May 2009. We found out that internet services in high schools are not utilized to their full capacity. (C) 2011 Published by Elsevier Ltd.
Citation - WoS: 26
Citation - Scopus: 33
Teaching Iso/Iec 12207 Software Lifecycle Processes: a Serious Game Approach
(Elsevier Science Bv, 2017) Yilmaz, Murat; Clarke, Paul M.; O'Connor, Rory V.; Aydan, Ufuk
Serious games involve applying game design techniques to tasks of a serious nature. In particular, serious games can be used as informative tools and can be embedded in formal education. Although there are some studies related to the application of serious games for the software development process, there is no serious game that teaches the fundamentals of the ISO/IEC 12207:1995 Systems and software engineering Software life cycle processes, which is an international standard for software lifecycle processes that aims to be 'the' standard that defines all the tasks required for developing and maintaining software. "Floors" is a serious game that proposes an interactive learning experience to introduce ISO/IEC 12207:1995 by creating different floors of a virtual environment where various processes of the standard are discussed and implemented. Inherently, it follows an iterative process based on interactive technical dialogues in a 3D computer simulated office. The tool is designed to assess the novice engineering practitioners knowledge and provide preliminary training for ISO/IEC 12207:1995 processes. By playing such a game, participants are able to learn about the details of this standard. The present study provides a framework for the exploration of research data obtained from computer engineering students. Results suggest that there is a significant difference between the knowledge gained among the students who have played Floors and those who have only participated in paper-based learning sessions. Our findings indicate that participants who played Floors tend to have greater knowledge of the ISO/IEC 12207:1995 standard, and as a result, we recommend the use of serious games that seem to be superior to traditional paper based approach.
Citation - WoS: 9
Citation - Scopus: 11
Thermodynamics of Small Platinum Clusters
(Elsevier Science Bv, 2006) Sebetci, A; Güvenç, ZB; Kökten, H
Using the Voter and Chen version of an embedded atom model, derived by fitting simultaneously to experimental data of both the diatomic molecule and bulk platinum, we have studied the melting behavior of free, small platinum clusters in the size range of N = 15-19 in the molecular dynamics simulation technique. We present an atom-resolved analysis method that includes physical quantities such as the root-mean-square bond-length fluctuation and coordination number for individual atoms as functions of temperature. The results show that as the Pt-15-Pt-18 clusters exhibit multistage melting, melting in Pt-19 cluster takes place in a single but interesting stage. None of these melting stages occurs at a specific temperature, rather, melting processes take place over a finite temperature range. This range is larger for less symmetric clusters. An ensemble of clusters in the melting region is a mixture of different isomeric forms of the clusters. The multistage melting and the occurrence of a single melting stage over a temperature range are two different phenomena. (c) 2005 Elsevier B.V. All rights reserved.

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