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Yayın Rate-distortion and complexity joint optimization for fast motion estimation in H.264 video coding(IEEE, 2006) Ateş, Hasan Fehmi; Kanberoğlu, Berkay; Altunbaşak, YücelH.264 video coding standard offers several coding modes including inter-prediction modes that use macroblock partitions with variable block sizes. Choosing a rate-distortion optimal mode among these possibilities contributes significantly to the superior coding efficiency of the H.264 encoder. Unfortunately, searching for optimal motion vectors of each possible subblock incurs a heavy computational cost. In this paper, in order to reduce the complexity of integer-pel motion estimation, we propose a rate-distortion and complexity joint optimization method that selects for each MB a subset of partitions to evaluate during motion estimation. This selection is based on simple measures of spatio-temporal activity within the MB. The procedure is optimized to minimize mode estimation error at a certain level of computational complexity. Simulation results show that the algorithm speeds up the motion estimation module by a factor of up to 20 with little loss in coding efficiency.Yayın Linear expansions for frequency selective channels in OFDM(Elsevier GMBH, 2006) Şenol, Habib; Çırpan, Hakan Ali; Panayırcı, ErdalModeling the frequency selective fading channels as random processes, we employ a linear expansion based on the Karhumen-Loeve (KL) series representation involving a complete set of orthogonal deterministic vectors with a corresponding uncorrelated random coefficients. Focusing on OFDM transmissions through frequency selective fading, this paper pursues a computationally efficient, pilot-aided linear minimum mean square error (MMSE) uncorrelated KL series expansion coefficients estimation algorithm. Based on such an expansion, no matrix inversion is required in the proposed MMSE estimator. Moreover, truncation in the linear expansion of channel is achieved by exploiting the optimal truncation property of the KL expansion resulting in a smaller computational load on the estimation algorithm. The performance of the proposed approach is studied through analytical and experimental results. We first exploit the performance of the MMSE channel estimator based on the evaluation of minimum Bayesian MSE. We also provide performance analysis results studying the influence of the effect of SNR and correlation mismatch on the estimator performance. Simulation results confirm our theoretical results and illustrate that the proposed algorithm is capable of tracking fast fading and improving performance.Yayın Predictive vector quantization of 3-D mesh geometry by representation of vertices in local coordinate systems(Elsevier Inc, 2007-08) Bayazıt, Uluğ; Orcay, Özgür; Konur, Umut; Gürgen, Sadık FikretIn predictive 3-D mesh geometry coding, the position of each vertex is predicted from the previously coded neighboring vertices and the resultant prediction error vectors are coded. In this work, the prediction error vectors are represented in a local coordinate system in order to cluster them around a subset of a 2-D planar subspace and thereby increase block coding efficiency. Alphabet entropy constrained vector quantization (AECVQ) of Rao and Pearlman is preferred to the previously employed minimum distortion vector quatitization (MDVQ) for block coding the prediction error vectors with high coding efficiency and low implementation complexity. Estimation and compensation of the bias in the parallelogram prediction rule and partial adaptation of the AECVQ codebook to the encoded vector source by normalization using source statistics, are the other salient features of the proposed coding system. Experimental results verify the advantage of the use of the local coordinate system over the global one. The visual error of the proposed coding system is lower than the predictive coding method of Touma and Gotsman especially at low rates, and lower than the spectral coding method of Karni and Gotsman at medium-to-high rates.Yayın Turkish L1 speakers’ use of the article in Spanish: an error analysis(Yakup Yılmaz, 2024-03-01) Çelikler Işıkal, BüşraFor Turkish learners of Spanish, the correct use of the article is particularly difficult area of grammar. Regardless of their level, such learners struggle to master this crucial aspect of the language. Accordingly, the present study combines a recent review of literature on article usage to investigate and classify errors in article use produced by Turkish students learning Spanish as a second foreign language (L2). The study was conducted at a private university in Türkiye during the fall term of the 2019–2020 academic year. The undergraduate participants (N=31) were enrolled on a range of degree programs and were taking Spanish as an elective at CEFR level A1. Data for the study came from the review exercises completed by the students in the final week of classes. For the purposes of this study, three activities were analyzed: one open-ended writing task and two controlled exercises. The analysis revealed that the most frequent errors involved gender agreement in noun-article pairs, incorrect article selection, omission, or inappropriate addition of the article. The theoretical and pedagogical implications of these findings for Turkish L1 learners of Spanish as a foreign language are discussed in order to provide a reference for SFL instructors tasked with helping their students overcome the difficulties that typically arise when encountering this element of grammar.Yayın Plaka tanıma sistemi için farklı bir yaklaşım(IEEE, 2009-06-26) Tamer, Engin; Çizmeci, BurakBu bildiride, bilgisayarlı görü ve örüntü tanıma alanlarında çok popüler olan plaka tanıma sistemi için farklı bir yakla¸sım sunuyoruz. Plaka tanıma sistemi genellikle üç ana bölüme ayrılır: plakanın yerinin saptanması, karakter bölütleme ve karakter tanıma. Plaka tanıma sisteminin en önemli bölümü olan plaka yerinin saptanmasında, yatay tarama ile arama alanını daralttıktan sonra, Türk plakalarında yer alan TR işaretini kullanan yeni ve özgün bir algoritma öneriyoruz. Yeri saptanan plakanın karakterlerinin bölütlenmesi için ikili imge üzerinde morfolojik işlemler uyguluyoruz. Son olarak, karakter tanıma işleminde ise, harf ve sayı yapay sinir ağlarını ayırarak hata oranını en küçültmeyi hedefliyoruz.Yayın Feature extraction from discrete attributes(IEEE, 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 extract new features by combining k discrete attributes, where for each subset of size k of the attributes, we generate all orderings of values of those attributes exhaustively. We then apply the usual univariate decision tree classifier using these orderings as the new attributes. Our simulation results on 16 datasets from UCI repository [2] show that the novel decision tree classifier performs better than the proper in terms of error rate and tree complexity. The same idea can also be applied to other univariate rule learning algorithms such as C4.5Rules [7] and Ripper [3].Yayın Searching for the optimal ordering of classes in rule induction(IEEE, 2012-11-15) Ata, Sezin; Yıldız, Olcay TanerRule induction algorithms such as Ripper, solve a K > 2 class problem by converting it into a sequence of K - 1 two-class problems. As a usual heuristic, the classes are fed into the algorithm in the order of increasing prior probabilities. In this paper, we propose two algorithms to improve this heuristic. The first algorithm starts with the ordering the heuristic provides and searches for better orderings by swapping consecutive classes. The second algorithm transforms the ordering search problem into an optimization problem and uses the solution of the optimization problem to extract the optimal ordering. We compared our algorithms with the original Ripper on 8 datasets from UCI repository [2]. Simulation results show that our algorithms produce rulesets that are significantly better than those produced by Ripper proper.Yayın A novel representation method for electromyogram (EMG) signal with predefined signature and envelope functional bank(IEEE, 2004) Gürkan, Hakan; Güz, Ümit; Yarman, Bekir Sıddık BinboğaIn this paper, a new method to model EMG signals by means of "Predefined Signature and Envelope Functional Banks (PSEB)" is presented. Since EMG signals present quasi-stationary behavior, any EMG signal Xi is modeled by the form of Xi ? Ci?K?R on a frame bases in this work. In this model, ?R is defined as the Predefined Signature Vector (PSV); ?K is referred to as Predefined Envelope Vector (PEV) and Ci is called the Frame-Scaling Coefficient (FSC). EMG signal for each frame is described in terms of the two indices "R" and "K" of PSEB and the frame -scaling coefficient Ci. Furthermore, It has been shown that the new method of modeling provides significant data compression while preserving the clinical information in the reconstructed signal.Yayın Investment in improved inventory accuracy in a decentralized supply chain(Elsevier Science BV, 2008-06) Uçkun, Canan; Karaesmen, Ahmet Fikri; Savaş, SelçukIt is known that inaccurate inventory records can lead to profit losses in a supply chain. Inventory records may not be correct due to various reasons such as transaction errors, misplacement, shrinkage, etc. In order to eliminate inventory inaccuracy, companies may invest in new information technologies such as radio frequency identification (RFID). In this paper, we consider a supply chain consisting of a retailer (distributor) and a supplier. We assume a single-period newsvendor-type setting where the retailer purchases the items from the supplier and distributes them to the regional warehouses. The paper focuses on the problem of finding the optimal investment levels that maximize profit by decreasing inventory inaccuracy. The optimal level of investment is examined both for the centralized and the decentralized systems under two scenarios: inventory sharing between the warehouses is allowed and not allowed. The coordination problem is also considered for both scenarios. Finally, several extensions of the model are considered: asymmetric warehouse parameters, demand and inventory inaccuracy correlation and imperfect RFID implementation.Yayın Digital color halftoning(IEEE-INST Electrical Electronics Engineers Inc, 2005-01) Baqai, F. A.; Lee, J. H.; Agar, A. Ufuk; Allebach, Jan P.Digital color halftoning is done to create the perception of a continuous-tone color image using the limited spatiochromatic discrimination capability of the human visual system. Several techniques to perform this task are now available. These techniques are broadly classified into three groups: approaches that characterize the spectral distribution created by a certain combination of colorant dots at a given printer addressable location; dot model based approaches; and empirical tone correction based approaches.
