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Publication Metadata only 2D scanning MEMS stage integrated with microlens arrays for high-resolution beam steering(IEEE, 2009) Department of Electrical and Electronics Engineering; N/A; Department of Electrical and Electronics Engineering; N/A; N/A; N/A; Ürey, Hakan; Gökçe, Sertan Kutal; Holmstrom, Sven; Arslan, Aslıhan; Ataman, Çağlar; Seren, Hüseyin Rahmi; Faculty Member; Master Student; Researcher; Master Student; PhD Student; Master Student; Other; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; N/A; 8579; N/A; N/A; N/A; N/A; N/A; N/AA novel MEMS stage using one set of comb fingers, capable of 2-axis motion is designed and developed. With an integrated 1.1mm square microlens-array it deflects 40um in-plane at 60V and 95um out-of-plane at 100V.Publication Metadata only 3D display dependent quality evaluation and rate allocation using scalable video coding(Ieee, 2009) N/A; N/A; Department of Electrical and Electronics Engineering; Saygılı, Görkem; Gürler, Cihat Göktuğ; Tekalp, Ahmet Murat; Master Student; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 26207It is well known that the human visual system can perceive high frequency content in 3D, even if that information is present in only one of the views. Then, the best 3D perception quality may be achieved by allocating the rates of the reference (right) and auxiliary (left) views asymmetrically. However the question of whether the rate reduction for the auxiliary view should be achieved by spatial resolution reduction (coding a downsampled version of the video followed by upsampling after decoding) or quality (QP) reduction is an open issue. This paper shows that which approach should be preferred depends on the 3D display technology used at the receiver. Subjective tests indicate that users prefer lower quality (larger QP) coding of the auxiliary view over lower resolution coding if a "full spatial resolution" 3D display technology (such as polarized projection) is employed. On the other hand, users prefer lower resolution coding of the auxiliary view over lower quality coding if a "reduced spatial resolution" 3D display technology (such as parallax barrier - autostereoscopic) is used. Therefore, we conclude that for 3D IPTV services, while receiving full quality/resolution reference view, users should subscribe to differently scaled versions of the auxiliary view depending on their 3D display technology. We also propose an objective 3D video quality measure that takes the 3D display technology into account.Publication Metadata only A blind fractionally spaced equalization algorithm with global convergence(IEEE, 2007) Department of Electrical and Electronics Engineering; Erdoğan, Alper Tunga; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 41624In this article we present a fractionally spaced extension of the SubGradient based Blind equalization Algorithm (SGBA). The basic features of the proposed algorithm are the non-linear constraint on the search vector and the selection of the weighting and step size applied to the search vector. It is proven that the algorithm is globally convergent to a perfect equalization point under the well known equalizability conditions for the fractionally spaced setting. The simulation results provided at the end of the article illustrates the relative merit of the proposed algorithm in comparison to the state of the art algorithms.Publication Metadata only A distributed qos routing architecture for scalable video streaming over multi-domain openflow networks(IEEE, 2012) Civanlar, Seyhan; Department of Electrical and Electronics Engineering; N/A; Tekalp, Ahmet Murat; Eğilmez, Hilmi Enes; Faculty Member; Master Student; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; 26207; N/AThis paper proposes a new Quality of Service (QoS) optimized routing architecture for video streaming over large-scale multi-domain OpenFlow networks managed by a distributed control plane, where each controller performs optimal routing within its domain and shares summarized intra-domain routing data with other controllers to reduce problem dimensionality for calculating inter-domain routing. We apply the proposed architecture to streaming of scalable (layered) videos, where the base layer routes are dynamically optimized to fulfill a required QoS level, while enhancement layers follow traditional shortest path. We show that the proposed solution approaches the expensive non-scalable globally optimal solution (single controller for the whole network) in terms of received video quality under various congestion scenarios.Publication Metadata only A family of bounded component analysis algorithms(IEEE, 2012) Department of Electrical and Electronics Engineering; Erdoğan, Alper Tunga; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 41624Bounded Component Analysis (BCA) has recently been introduced as an alternative method for the Blind Source Separation problem. Under the generic assumption on source boundedness, BCA provides a flexible framework for the separation of dependent (even correlated) as well as independent sources. This article provides a family of algorithms derived based on the geometric picture implied by the founding assumptions of the BCA approach. We also provide a numerical example demonstrating the ability of the proposed algorithms to separate mixtures of some dependent sources.Publication Metadata only A feasibility study of two user downlink transmission for IS-856 system(IEEE, 2004) Dost, Serkan; Bhargava, Vijay K.; Department of Electrical and Electronics Engineering; Sunay, Mehmet Oğuz; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; N/AThis work presents a feasibility study for a possible extension to the IS-856 (HDR, 1xEV-DO) standard in terms of allowing two user transmission in the system downlink. Since the 1.25 MHz bandwidth of this system is not perfectly frequency flat, the one user at a time scheme is no longer optimal in theory. Furthermore, the two user transmission allows for more granular data rate selection by the base station. The extension requires minimum changes to the physical layer of the IS-856 standard and is compatible with the existing physical layer specifications with no additional overhead required in the downlink. A packet scheduling algorithm that is able to take advantage of the two user transmission is presented. The performance of the proposal is studied with physical layer and system simulations. The simulation results indicate that the proposed extension modestly increases the average system data rate that may not justify the required complexity.Publication Metadata only A flexible multiple description coding framework for adaptive peer-to-peer video streaming(IEEE-Inst Electrical Electronics Engineers Inc, 2007) Akyol, Emrah; Civanlar, M. Reha; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 26207Efficient peer-to-peer (P2P) video streaming is a challenging task due to time-varying nature of both the number of available peers and network/channel conditions. This paper proposes a novel adaptive P2P video streaming system, which features: i) a new flexible multiple-description coding (F-MDC) framework, such that the number of base and enhancement descriptions, and the rate and redundancy level of each description can be adapted on the fly (by only post-processing of the encoded bitstream), and ii) a new adaptive TCP-friendly rate-controlled (TFRC), on-demand, many-to-one P2P video streaming solution based on the proposed F-MDC framework. We extend the highly scalable video coder [17], [18] to MDC within the proposed F-MDC framework. Optimization of the design parameters of the proposed F-MDC method is discussed within the context of the proposed adaptive P2P streaming solution, where the number and quality of available streaming peers/paths are a priori unknown and vary in time. Experimental results, by means of NS-2 network simulation of a P2P video streaming system, show that adaptation of the number, type of descriptions and the rate and redundancy level of each description according to network conditions yields significantly superior performance when compared to other scalable MDC schemes using a fixed number of descriptions/layers with fixed rate and redundancy level.Publication Metadata only A high-frequency comb-actuated resonant MEMS scanner for microdisplays(IEEE, 2011) Brown, Dean; Davis, Wyatt O.; Department of Electrical and Electronics Engineering; N/A; Department of Electrical and Electronics Engineering; Ürey, Hakan; Gökçe, Sertan Kutal; Holmstrom, Sven; Faculty Member; Master Student; Researcher; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; 8579; N/A; N/AA high-frequency novel torsional MEMS scanner is developed for high resolution microdisplays employing a multi-frame geometry. For the torsional mirror, 26.7° and 36.1° total-optical-scan-angle are achieved at resonance, at atmospheric pressure and vacuum respectively.Publication Metadata only A moving window algorithm for 1∞ norm based blind source separation approach(European Association for Signal Processing, 2005) Department of Electrical and Electronics Engineering; Erdoğan, Alper Tunga; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 41624An l ∞ norm based Source Separation Method has recently been introduced [1, 2], with the corresponding subgradient based algorithm that has a simple update rule. In this article, we propose a moving window modification to this algorithm, where instead of a long fixed window, a shorter length moving window is used. The simulation results for different blind source separation setups suggest that a significant level of complexity reduction can be achieved via use of the proposed approach.Publication Metadata only A new scalable multi-view video coding configuration for robust selective streaming of free-viewpoint TV(IEEE, 2007) Özbek, Nükhet; Tunalı, E. Turhan; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 26207Free viewpoint TV (FTV) is a new media format that allows a user to change his/her viewpoint freely. To this effect, multi-view video must be coded to sAtışfy two conflicting requirements: i) achieve high compression efficiency, and ii) allow view switching with low delay. This paper proposes a new encoding configuration for scalable multi-view video coding, which achieves a compromise between the two requirements. In the new scalable multi-view configuration, the base layer is encoded with inter-view prediction at a minimum acceptable quality, while enhancement layers for each view only depend on their respective base layers (with no interview prediction). Thus, the base layer shall be served to all users, while enhancement layers shall be served selectively to users depending on their channel bandwidth and viewing direction. We compare the compression efficiency of the proposed method with those of non-scalable multi-view coding (MVC) and simulcast (H.264/AVC of each view independently) solutions.