Publications without Fulltext
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/3
Browse
8 results
Search Results
Publication Metadata only Per-GOP bitrate adaptation for H.264 compressed video sequences(Springer-Verlag Berlin, 2006) De Martin, Juan Carlos; Department of Computer Engineering; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; De Vito, Fabio; Özçelebi, Tanır; Civanlar, Mehmet Reha; Tekalp, Ahmet Murat; Other; PhD Student; Faculty Member; Faculty Member; Department of Computer Engineering; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; N/A; 16372; 26207In video transmission over packet data networks, it may be desirable to adapt the coding rate according to bandwidth availability. Classical approaches to rate adaptation are bitstream switching, requiring the storage of several pre-coded versions of a video, or layered (scalable) video coding, which has coding efficiency and/or complexity penalties. In this paper we propose a new GOP-level rate adaptation scheme for a single stream, variable target bitrate H.264 encoder; this allows each group of pictures (GOP) to be encoded at a specified bitrate. We first compare the performance of the standard H.264 rate control algorithm with the proposed one in the case of constant target bitrate. Then, we present results on how close the new technique can track a specified per-GOP target bitrate schedule. Results show that the proposed approach can obtain the desired target rates with less than 5% error.Publication Metadata only Cross-layer scheduling with content and packet priorities for optimal video streaming over 1xEV-DO(Springer-Verlag Berlin, 2006) De Martin, Juan Carlos; N/A; Department of Computer Engineering; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Özçelebi, Tanır; De Vito, Fabio; Sunay, Mehmet Oğuz; Tekalp, Ahmet Murat; Civanlar, Mehmet Reha; PhD Student; Other; Faculty Member; Faculty Member; Faculty Member; Department of Computer Engineering; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; College of Engineering; College of Engineering; N/A; N/A; N/A; 26207; 16372Maximization of received video quality and application-level service fairness are the two principal objectives of multi-user wireless video streaming. The user and packet scheduling mechanisms employed are the determining factors on the communication system performance and must utilize multiple layers of the OSI protocol stack. The semantic and decodability (concealment related) importance and hence priorities of video packets can be considered at the application layer. In this paper, the use of video content and packet priorities for multi-objective optimized (MOO) scheduling in 1xEV-DO system is introduced. Rate adaptive AVC/H.264 encoding is used for content adaptation and a user with the least buffer fullness, best channel throughput and highest video packet importance is targeted for scheduling. Hence, losses are forced to occur at packets with low semantic/decodability importance. Results show that the proposed framework achieves 1-to-2 dB's better PSNR in high importance temporal regions compared to the state-of-the-art CBR encoding case.Publication Metadata only What can video analysis do for MPEG standards?(Springer, 2003) Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 26207Video analysis techniques can be classified as low-level and semantic-level analysis techniques. It appears that while low-level video analysis techniques are becoming more and more important for generic rectangular MPEG-4/H.264 video compression, automatic semantic-level analysis techniques are useful (for MPEG-4 object extraction and MPEG-7 indexing/summarization) only in limited well-constrained domains.Publication Metadata only Projective Kalman Filter: multiocular tracking of 3D locations towards scene understanding(Springer-Verlag Berlin, 2005) Canton Ferrer, C.; Casas, J. R.; Pardas, M.; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 26207This paper presents a novel approach to the problem of estimating and tracking 3D locations of multiple targets in a scene using measurements gathered from multiple calibrated cameras. Estimation and tracking is jointly achieved by a newly conceived computational process, the Projective Kalman filter (PKF), allowing the problem to be treated in a single, unified framework. The projective nature of observed data and information redundancy among views is exploited by PKF in order to overcome occlusions and spatial ambiguity. To demonstrate the effectiveness of the proposed algorithm, the authors present tracking results of people in a SmartRoom scenario and compare these results with existing methods as well.Publication Metadata only Evaluation of a mixed reality head-mounted projection display to support motion capture acting(Springer, 2018) Kade, Daniel; Lindell, Rikard; Department of Electrical and Electronics Engineering; Department of Media and Visual Arts; Ürey, Hakan; Özcan, Oğuzhan; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Department of Media and Visual Arts; College of Engineering; College of Social Sciences and Humanities; 8579; 12532Motion capture acting is a challenging task, it requires trained and experienced actors who can highly rely on their acting and imagination skills to deliver believable performances. This is especially the case when preparation times are short and scenery needs to be imagined, as it is commonly the case for shoots in the gaming industry. To support actors in such cases, we developed a mixed reality application that allows showing digital scenery and triggering emotions while performing. In this paper we tested our hypothesis that a mixed reality head-mounted projection display can support motion capture acting through the help of experienced motion capture actors performing short acting scenes common for game productions. We evaluated our prototype with four motion capture actors and four motion capture experts. Both groups considered our application as helpful, especially as a rehearsal tool to prepare performances before capturing the motions in a studio. Actors and experts indicated that our application could reduce the time to prepare performances and supports the set up of physical acting scenery.Publication Metadata only Resistive hydrogen sensors based on nanostructured metals and metal alloys(Amer Scientific Publishers, 2013) N/A; Department of Electrical and Electronics Engineering; Kılınç, Necmettin; Researcher; Department of Electrical and Electronics Engineering; College of Engineering; 59959Hydrogen (H-2), as a renewable energy source, has numerous applications such as chemical production, fuel cell technology, rocket engines, fuel for cars etc. The detection of H-2 is so important in safety issue due to the flammable and explosive properties of H-2 gas, in a H-2 source for leak detection and in H-2 production process because of real-time quantitative analysis of production. This paper reviews resistive type H-2 sensor based on palladium (Pd), platinum (Pt) and their alloy nano-structures in the forms of thin films, nanoporous films, nanowires, nanoparticles, nanotubes, etc. The sensing mechanism of the nanostructured Pd and Pt resistive sensor is discussed in separated section. Nanostructured Pd sensors show a decrease or an increase in their resistance towards H-2 gas depending on continuity of the nanostructure and will be examined in two parts: discontinuous (nano-gap based) and continuous Pd and Pd alloy nanostructure sensors. on the contrary to Pd nanostructure sensor, nanostructured Pt sensors require oxygen (O-2) to operate. There are limited numbers of publications about nanostructured Pt and Pt alloy sensors, so further investigation are needed to well understand sensing mechanism of the Pt sensors.Publication Metadata only Quadrature spatial modulation based multiuser MIMO transmission system(Wiley, 2020) Castillo-Soria; Francisco Ruben; Cortez, Joaquin; Cardenas-Juarez, Marco; Department of Electrical and Electronics Engineering; Başar, Ertuğrul; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 149116This study presents a multiuser (MU) multiple-input multiple-output (MIMO) downlink transmission scheme based on the quadrature spatial modulation (QSM) concept, which uses the indices of the non-zero entries in its transmission vector to modulate and transmit an independent sequence of bits for each user in the system. The MU interference is removed by using a matrix precoding technique based on channel state information (CSI) known as block diagonalisation (BD). The performance of the proposed scheme is compared with the conventional MU-MIMO-BD system for uncorrelated Rayleigh fading channels and correlated fading channels with imperfect CSI in the reception. Additionally, a low-complexity near maximum likelihood (ML) detection algorithm for the MU-MIMO-QSM signal's detection is proposed. For the considered cases, the proposed MU-MIMO-QSM scheme exhibits gains up to 1 dB in bit error rate performance and a reduction in detection complexity up to 93% as compared to the conventional MU-MIMO-BD scheme for the optimal ML detection. The proposed algorithm performs very near to the optimal ML detector whilst achieving a complexity reduction of up to 58%.Publication Metadata only Special issue on quantum communications - guest editorial(Scientific Association for Infocommunications, 2012) Imrc, Sandor; Bacsardi, Laszlo; Department of Electrical and Electronics Engineering; Akan, Özgür Barış; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 6647