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Yayın Spectral coding of mesh geometry with a hierarchical set partitioning algorithm(Spie-Int Soc Optical Engineering, 2008) Konur, Umut; Bayazıt, Uluğ; Ateş, Hasan Fehmi; Gürgen, Sadık FikretThis work proposes a progressive mesh geometry coder, which expresses geometry information in terms of spectral coefficients obtained through a transformation and codes these coefficients using a hierarchical set partitioning algorithm that assigns right priorities to those coefficients at all bit planes. The spectral transformation used is the one proposed in [8] where the spectral coefficients are obtained by projecting the mesh geometry on an orthonormal basis determined by mesh topology. The set partitioning method used in coding, treats spectral coefficients belonging to the three spatial coordinates with the right priority at all bit planes and realizes a truly embedded system by achieving implicit bit allocation via joint coding the zeroes of coefficients at the bit planes. The experiments performed on common irregular meshes reveal that the rate-distortion performance of the coder is significantly superior to the coding system proposed in [8].Yayın 3-B nesne bilgilerinin vektor nicemleme yöntemleri ile sıkıştırılması(IEEE, 2004-10-25) Orcay, Özgür; Konur, Umut; Bayazıt, Uluğ; Gürgen, Sadık FikretBu çalışmanın amacı, bağlanırlık kodlaması için gerçeklenmiş [I]'deki algoritmayı bazı yenilikler ile uygulamak ve koordinat sıkıştırması için 3-B (3 Boyutlu) nesne gösterimleri alanında kullanımı kısıtlı olan kayıplı bir göz sıkıştırma algoritması geliştirmektir. İlk kısımda, bağlanırlık kodlamasını gerçeklemek için kullanılan algoritma ([I]) üzerinde yapılan ufak değişiklikler ile amaca uygun iyileştirmeler sağlanmıştır. İkinci kısımda ise bu alanda kullanımı kısıtlı olan Vektor Nicemleme yöntemleri gerçekleştirilmiştir. Çalışmanın diğer önerilen algoritmalardan farkı, Entropi kısıtlı Vektör Nicemleme (ECVQ) yönteminin geometri sıkıştırma algoritması olarak kullanılmasıdır. Bu sayede gerek bağlanırlık gerekse geometri sıkıştırması algoritmaları için tatmin edici hata düşürme oranlarına ulaşılmıştır.Yayın ICamp - The educational web for higher education(Springer Verlag, 2006) Kieslinger, Barbara; Wild, Fridolin; Arsun, Onur İhsaniCamp is an EC-funded research project in the area of Technology Enhanced Learning (TEL) that aims to support collaboration and social networking across systems, countries and disciplines in higher education. The concept of an iCamp Space will build on existing interfaces and integrate shared community features. Interoperability amongst different open source learning systems and tools is the key to successful sustainability of iCamp. The content for this collaboration within social communities is provided via distributed networked repositories including, for example, content brokerage platforms, online libraries, and learning object databases. The innovative pedagogical model of iCamp is based on social constructivist learning theories. iCamp creates an environment for a new way of social networking in higher education that puts more emphasis on self-organised, self-directed learning, social networking and cross-cultural collaboration.Yayın Model adaptation for dialog act tagging(IEEE, 2006) Tür, Gökhan; Güz, Ümit; Hakkani Tür, DilekIn this paper, we analyze the effect of model adaptation for dialog act tagging. The goal of adaptation is to improve the performance of the tagger using out-of-domain data or models. Dialog act tagging aims to provide a basis for further discourse analysis and understanding in conversational speech. In this study we used the ICSI meeting corpus with high-level meeting recognition dialog act (MRDA) tags, that is, question, statement, backchannel, disruptions, and floor grabbers/holders. We performed controlled adaptation experiments using the Switchboard (SWBD) corpus with SWBD-DAMSL tags as the out-of-domain corpus. Our results indicate that we can achieve significantly better dialog act tagging by automatically selecting a subset of the Switchboard corpus and combining the confidences obtained by both in-domain and out-of-domain models via logistic regression, especially when the in-domain data is limited.Yayın Spektral yöntemler ve küme bölüntüleme yaklaşımlarıyla 3B nesne bilgilerinin sıkıştırılması(IEEE, 2006) Konur, Umut; Bayazıt, Uluğ; Gürgen, Sadık Fikret; Orcay, ÖzgürSpekral dönüşümle elde edilen katsayıları küme bölüntüleme yaklaşımlarıyla işleyerek 3B nesne geometrilerini kodlayan bir yöntem öneriyoruz. [1]' de anlatılan spektral yöntem düzensiz tel filelerde yüksek hız-bozunum başarımı sağlamakla kalmayıp, geriçatımı, katsayı vektörünü kırparak elde edilen ve toplam enerjisinin büyük bir bölümünü taşıyan alt vektörüyle gerçekleştirdiği için aşamalı iletim de sağlayabilmektedir. Önerilen spektral yöntemde, nesne geometrisinin [1]' de olduğu gibi topolojiden türetilen birimdik bir taban üzerine izdüşümü alınmakta ve elde edilen katsayılar [2]' nin küme bölüntüleme algoritmasıyla kodlanmaktadır. Yöntem üç koordinata ait spektral katsayılara dolaylı bit ataması başardığı ve önemli katsayılara ait konum bilgisini bu katsayıların bit düzlemlerindeki sıfırlarını birleşik kodlayarak verimli kodlama sağladığı için, yaygın düzensiz tel fileler üzerinde yaptığımız deneylerde [1]' e göre daha iyi hız-bozunum başarımı vermektedir. Üretilen bit katarı da tamamen gömülüdür.Yayın Extraction and selection of muscle based features for facial expression recognition(IEEE Computer Soc, 2014-12-04) Benli, Kristin Surpuhi; Eskil, Mustafa TanerIn this study we propose a new set of muscle activity based features for facial expression recognition. We extract muscular activities by observing the displacements of facial feature points in an expression video. The facial feature points are initialized on muscular regions of influence in the first frame of the video. These points are tracked through optical flow in sequential frames. Displacements of feature points on the image plane are used to estimate the 3D orientation of a head model and relative displacements of its vertices. We model the human skin as a linear system of equations. The estimated deformation of the wireframe model produces an over-determined system of equations that can be solved under the constraint of the facial anatomy to obtain muscle activation levels. We apply sequential forward feature selection to choose the most descriptive set of muscles for recognition of basic facial expressions.Yayın A novel method to represent ECG signals via predefined personalized signature and envelope functions(IEEE, 2001) Yarman, Bekir Sıddık Binboğa; Gürkan, Hakan; Güz, Ümit; Aygün, B.In this paper, a new method to model ECG signals by means of "Predefined Personalized Signature and Envelope Functions" is presented. ECG signals are somewhat unique to a person. Moreover, it presents quasi-stationary behavior. Therefore in this work, on a frame basis, personal ECG signals X-i(t) is modeled by the form of X-i(t) approximate to C(i)phi(i)(t) alpha(i)(t). In this model, phi(i)(t) is defined as the Personalized Signature Function (PSF); alpha(i)(t) is referred to as Personalized Envelope Function (PEF) and C-i is called the Frame-Scaling Coefficient (FSC). It has been demonstrated that for each person, the sets Phi = {phi(k)(t)} and A = {alpha(r)(t)} constitute a "Predefined Personalized Functional Bases or Banks (PPFB)" to describe any measured ECG signal. Almost optimum forms of (PPFB), namely {alpha(r)(t)}, {phi(k)(t)} pairs are generated in the Least Mean Square (LMS) sense. Thus, ECG signal for each frame is described in terms of the two indices "R" and "K" of PPFB and the frame-scaling coefficient Ci. It has been shown that the new method of modeling provides significant data compression. Furthermore, once PPFB are stored on each communication node, transmission of ECG signals reduces to the transmission of indexes "R" and "K" of pairs and the coefficients C-i, which also result in considerable saving in the transmission band.Yayın İfade tanıma için yüz anatomisine dayalı öznitelikler(IEEE, 2014-04-23) Benli, Kristin Surpuhi; Eskil, Mustafa TanerBu çalışmada yüz ifadesi tanıma için kas kuvvetlerine dayalı yeni öznitelikler öneriyoruz. Yüz üzerinde seçtiğimiz noktaların video üzerindeki hareketlerini izleyerek kas kuvvetlerini çözüyoruz. Yüz noktaları, ilk video çerçevesi üzerinde, kas kuvvet alanları üzerinde ilklendirilir. Bu noktalar optik akış algoritması ile izlenir. Noktaların devinimleri yüzün 3 boyutlu yönelimi ve yüz ifadesine dayalı bağıl devinimleri kestirmek için kullanılır. İnsan yüzünü yaylarla, artık-belirtilmiş doğrusal bir denklem sistemi olarak modelliyoruz. Bu sistemi yüz anatomisi kısıtı altında, kas kuvvetleri için çözüyoruz. Ardışık ileri seçim yaparak, temel yüz ifadeleri için en betimleyici kas kümesini belirliyoruz.Yayın Predictive vector quantization of 3-D polygonal mesh geometry by representation of vertices in local coordinate systems(IEEE, 2005) Bayazıt, Uluğ; Orcay, Özgür; Konur, Umut; Gürgen, Sadık FikretA large family of lossy 3-D mesh geometry compression schemes operate by predicting the position of each vertex from the coded neighboring vertices and encoding the prediction error vectors. In this work, we first employ entropy constrained extensions of the predictive vector quantization and asymptotically closed loop predictive vector quantization techniques that have been suggested in [3] for coding these prediction error vectors. Then we propose the representation of the prediction error vectors in a local coordinate system with an axis coinciding with the surface normal vector in order to cluster the prediction error vectors around a 2-D subspace. We adopt a least squares approach to estimate the surface normal vector from the non-coplanar, previously coded neighboring vertices. Our simulation results demonstrate that the prediction error vectors can be more efficiently vector quantized by representation in local coordinate systems than in global coordinate systems.Yayın Statistical analysis of bus transportation networks of Istanbul(World Scientific Publishing Co Pte Ltd, 2016) Çoban, Veysel; Atan, Sabri TankutTransportation networks such as railway, airport and bus networks are the real-world networks whose inherent statistical properties characterize and differentiate the networks. In order to understand the network characteristics of bus transportation networks (BTNs) of Istanbul, we analyzed its network properties such as degree distributions, clustering coefficients and assortativity. BTNs of Istanbul is defined into three networks as the existence and nonexistence of the metrobus and existence of third- bridge. They are also graphically represented within C-, L- and P-Space topologies that are defined with the connection of the bus stops or routes. Statistical results obtained from network properties reflected the characteristics of the BTNs of Istanbul and give an information about the effects of the metrobus lines and third bridge on the BTNs in Istanbul.
