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Yayın Univariate margin tree(Springer, 2010) Yıldız, Olcay TanerIn many pattern recognition applications, first decision trees are used due to their simplicity and easily interpretable nature. In this paper, we propose a new decision tree learning algorithm called univariate margin tree, where for each continuous attribute, the best split is found using convex optimization. Our simulation results on 47 datasets show that the novel margin tree classifier performs at least as good as C4.5 and LDT with a similar time complexity. For two class datasets it generates smaller trees than C4.5 and LDT without sacrificing from accuracy, and generates significantly more accurate trees than C4.5 and LDT for multiclass datasets with one-vs-rest methodology.Yayın Cointegration and adjustment dynamics of REIT and stock markets during the global financial and European debt crises(Inderscience Publishers, 2020-06-03) Erol, Ümit; Yüksel, Sadettin Aydın; Yüksel, Aslı; Öztürk, HakkıThis paper analyses the cointegration relationship between the REIT and stock markets of ten developed countries during the 2005-2013 period, which is characterised by the global financial and the European debt crises. Given the structural breaks in the data, the effect of these two crises is examined separately by dividing the sample period into four equal parts and by using M-TAR cointegration analysis. The results suggest that the cointegration between the stock and REIT markets was not a globally observed feature prior to the twin crises. The strong and globally valid cointegration observed after 2007 was due to the common negative response of both markets to the unexpected massive shocks. These shocks also led to bilateral causality and strong feedback effects between these two markets, thus strictly limiting the diversification benefits of the REIT market during the crisis period.Yayın GIS aided vulnerability assessment for roads(Springer Science and Business Media B.V., 2022-04-21) Çalışkan, Berna; Atahan, Ali Osman; Kesten, Ali SercanRoad networks are vulnerable to natural disasters such as floods, earthquakes and forest fires which can adversely affect the travel on the network. However, not all road links equally affect the travel conditions in a given network; typically some links are more critical to the network functioning than the others. The first stage of study involves the investigation of geological conditions. Image classification used for extracting information classes from ‘Geological Map of Istanbul area’ image file. The resulting raster layer used to create thematic map. A reclassification was performed for lithologic types. The second stage involves analyzing topological situation. A slope map prepared and classified according to percentage of slope values. The third phase is the analysis and interpretation of the accumulated data to establish suitable and applicable road vulnerability scores. The information in the source data for each vulnerability factor are classified into three different vulnerability scores: +2 (considerably increases vulnerability), +1 (increases vulnerability) and 0 (does not increase vulnerability) by using a vulnerability score table. The study area was categorized into three different traffic analysis zones as: (1) least favorable area; (2) favorable area; (3) most favorable area. Vulnerability values obtained to measure serviceability of critical links in dense urban road networks and applies them to the case of ‘Beyoğlu’ region. Thematic layers were prepared using the Geographic Information System (GIS), and they were then combined to produce the serviceability of road links in the ‘Beyoğlu’ region. Consequently, A site specific vulnerability index is proposed, considering the serviceability of road links. A conceptual flowchart of the GIS processing steps taken to obtain the vulnerability index is illustrated.Yayın A broadband microwave amplifier design by means of immittance based data modelling tool(IEEE, 2002) Kılınç, Ali; Pınarbaşı, Hacı; Şengül, Metin; Yarman, Bekir Sıddık BinboğaIn this paper a practical broadband microwave amplifier design algorithm is introduced utilizing the immittance data-modelling tool. In the course of design, first, the optimum input and output terminations for the active device are produced employing the real frequency technique. Then, these terminations are modelled utilizing the new immittance-modelling tool to synthesize the front-end and back-end matching networks. An example is included to exhibit the implementation of the proposed design algorithm to construct a single stage BJT amplifier over a wide frequency band. It is expected that the proposed design algorithm will find applications to realize wideband microwave amplifiers put on MMIC for mobile communication.Yayın Analyzing the benefits and challenges of building information modelling and life cycle assessment integration(Springer, 2020) Azizoğlu, Heval Botan; Seyis Kazazoğlu, SenemPrevious studies show that the architecture, engineering and construction (AEC) industry contributes up to 1/3 of global GHG emissions. With the aim of mitigating negative impacts of AEC industry on the natural environment, the integrated use of advanced technological instruments has been increasing in the last decade. The integration of Building Information Modelling (BIM) and Life Cycle Assessment (LCA), which is one of the cutting-edge technological instruments, provides reduction of the total time spent and the improvement of the application while minimizing the environmental impacts throughout the life cycle of the facility. The main objective of this research study is to identify the benefits and challenges of BIM and LCA integration. In order to achieve the research objective of this study, a comprehensive literature review was conducted. Twenty-two types of benefits and seven types of challenges were identified for the integrated use of BIM and LCA in the AEC industry. The major contribution of this study is a comprehensive identification of the benefits and challenges of BIM-LCA integration. The results of this study may contribute to an increase in the utilization of the BIM-LCA integration in the AEC industry that in return allows decreasing negative environmental impacts of buildings through their life-cycle.Yayın Regularizing soft decision trees(Springer, 2013) Yıldız, Olcay Taner; Alpaydın, Ahmet İbrahim EthemRecently, we have proposed a new decision tree family called soft decision trees where a node chooses both its left and right children with different probabilities as given by a gating function, different from a hard decision node which chooses one of the two. In this paper, we extend the original algorithm by introducing local dimension reduction via L-1 and L-2 regularization for feature selection and smoother fitting. We compare our novel approach with the standard decision tree algorithms over 27 classification data sets. We see that both regularized versions have similar generalization ability with less complexity in terms of number of nodes, where L-2 seems to work slightly better than L-1.Yayın Auto Train Brain increases the variance of the gamma band sample entropy in the left hemisphere in dyslexia: a pilot study(Springer Science and Business Media Deutschland GmbH, 2023) Eroğlu, GünetAuto Train Brain is a mobile app that improves reading speed and reading comprehension in dyslexia. The efficacy of Auto Train Brain was proven with a clinical trial. We have analyzed the long-term training effects of the Auto Train Brain on dyslexic children. We have collected QEEG data from 14 channels from 21 dyslexic children for 100 sessions and calculated the sample entropy in the gamma bands for the left posterior brain (T7, P7, and O1). Although the gamma band values fluctuate and no permanent increase in the gamma band values is detected after Auto Train Brain training at T7, P7, and O1, the variance of gamma band sample entropy increases as the neurofeedback session number increases. We have concluded that the Auto Train Brain increases the flexibility of the left brain in dyslexia.Yayın Efficient quality of multimedia experience using perceptual quality metrics(Springer-Verlag Berlin, 2016) Gaurav, Rahul; Ateş, Hasan FehmiAlthough there are very few metrics which correlate well with the Human Visual System (HVS), most of them do not. We extensively studied about the Video Quality Assessment (VQA) of 2D svideos for enhancing the Quality of Experience (QoE) using better Quality of Service (QoS). We propose a solution which helps us to find a high correlation between HVS and the objective metrics using Perceptual Quality Metrics (PQM). The motive behind this work is to introduce an objective metric that is adequate to predict the Mean Opinion Score (MOS) of distorted video sequences based on the Full Reference (FR) method.Yayın Constructing a Turkish constituency parse treeBank(Springer Verlag, 2016) Yıldız, Olcay Taner; Solak, Ercan; Çandır, Şemsinur; Ehsani, Razieh; Görgün, OnurIn this paper, we describe our initial efforts for creating a Turkish constituency parse treebank by utilizing the English Penn Treebank. We employ a semiautomated approach for annotation. In our previouswork [18], the English parse trees were manually translated to Turkish. In this paper, the words are semi-automatically annotated morphologically. As a second step, a rule-based approach is used for refining the parse trees based on the morphological analyses of the words. We generated Turkish phrase structure trees for 5143 sentences from Penn Treebank that contain fewer than 15 tokens. The annotated corpus can be used in statistical natural language processing studies for developing tools such as constituency parsers and statistical machine translation systems for Turkish.Yayın Virtual team effectiveness using dyadic teams(IEEE, 2007) Karayaz, Gamze; Keating, Charles B.The importance of effectiveness for virtual teamwork continues to gain momentum as technology and globalization of work accelerate. The implementation of virtual teams provides one approach to enhance competitiveness, overcoming the disadvantages of space and time differences through collaborative technologies. The influence of structure to virtual team performance has not been clearly established in the literature. The purpose of this research study was to investigate the effectiveness of a dyad structured approach for virtual teams using a quasi-experimental research design. A virtual dyadic team is considered as two person-structured teams working on a particular task in a virtual collaborative environment. This research investigated four questions related to the influence of structure on virtual team effectiveness related to task performance, communication frequency, and team satisfaction.The results showed significance differences between the two virtual teams. Dyadic teams performed better in arriving at the task solution using less communication to finish the task. Dyadic teams were also more satisfied with their task solution than the self-structured teams. However, results indicated that dyadic teams were not satisfied with operating as a dyadic team in this study. The research also demonstrated that team satisfaction was the most significant predictor of virtual team effectiveness. The paper concludes with implications for technology managers and suggests guidance for improved effectiveness in design and implementation of virtual teams.
