| 1. |
- Al-Zubaidy, Hussein, et al.
(författare)
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Reliable Video Streaming With Strict Playout Deadline in Multihop Wireless Networks
- 2017
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Ingår i: IEEE transactions on multimedia. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1520-9210 .- 1941-0077. ; 19:10, s. 2238-2251
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Tidskriftsartikel (refereegranskat)abstract
- Motivated by emerging vision-based intelligent services, we consider the problem of rate adaptation for high-quality and low-delay visual information delivery over wireless networks using scalable video coding. Rate adaptation in this setting is inherently challenging due to the interplay between the variability of the wireless channels, the queuing at the network nodes, and the frame-based decoding and playback of the video content at the receiver at very short time scales. To address the problem, we propose a low-complexity model-based rate adaptation algorithm for scalable video streaming systems, building on a novel performance model based on stochastic network calculus. We validate the analytic model using extensive simulations. We show that it allows fast near-optimal rate adaptation for fixed transmission paths, as well as cross-layer optimized routing and video rate adaptation in mesh networks, with less than 10% quality degradation compared to the best achievable performance.
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| 2. |
- Amara, Umme, et al.
(författare)
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Molecular Intercommunication between the Complement and Coagulation Systems
- 2010
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 185:9, s. 5628-5636
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Tidskriftsartikel (refereegranskat)abstract
- The complement system as well as the coagulation system has fundamental clinical implications in the context of life-threatening tissue injury and inflammation. Associations between both cascades have been proposed, but the precise molecular mechanisms remain unknown. The current study reports multiple links for various factors of the coagulation and fibrinolysis cascades with the central complement components C3 and C5 in vitro and ex vivo. Thrombin, human coagulation factors (F) XIa, Xa, and IXa, and plasmin were all found to effectively cleave C3 and C5. Mass spectrometric analyses identified the cleavage products as C3a and C5a, displaying identical molecular weights as the native anaphylatoxins C3a and C5a. Cleavage products also exhibited robust chemoattraction of human mast cells and neutrophils, respectively. Enzymatic activity for C3 cleavage by the investigated clotting and fibrinolysis factors is defined in the following order: FXa > plasmin > thrombin > FIXa > FXIa > control. Furthermore, FXa-induced cleavage of C3 was significantly suppressed in the presence of the selective FXa inhibitors fondaparinux and enoxaparin in a concentration-dependent manner. Addition of FXa to human serum or plasma activated complement ex vivo, represented by the generation of C3a, C5a, and the terminal complement complex, and decreased complement hemolytic serum activity that defines exact serum concentration that results in complement-mediated lysis of 50% of sensitized sheep erythrocytes. Furthermore, in plasma from patients with multiple injuries (n = 12), a very early appearance and correlation of coagulation (thrombin-antithrombin complexes) and the complement activation product C5a was found. The present data suggest that coagulation/fibrinolysis proteases may act as natural C3 and C5 convertases, generating biologically active anaphylatoxins, linking both cascades via multiple direct interactions in terms of a complex serine protease system. The Journal of Immunology, 2010, 185: 5628-5636.
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| 3. |
- Barry, Ousmane, et al.
(författare)
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Robust Motion-Compensated Orthogonal Video Coding Using EBCOT
- 2010
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Ingår i: Proceedings - 4th Pacific-Rim Symposium on Image and Video Technology, PSIVT 2010. - : IEEE. - 9781424488902 ; , s. 264-269
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Konferensbidrag (refereegranskat)abstract
- This paper proposes a rate-distortion control for motion-compensatedorthogonal video coding schemes and evaluates its robustness to packet loss as faced in, e.g., IP networks. The robustness of standard hybrid video coding is extensively studied in the literature. In contrast, motion-compensated orthogonal subbands offer important advantages and new features for robust video transmission. In this work, we utilize so-called uni-directional motioncompensated orthogonal transforms in combination with entropy coding similar to EBCOT known from JPEG2000.The approach provides a flexible embedded structure and allows flexible rate-distortion optimization. Moreover, it may even permit separate encoding and rate control. The proposed rate-distortion control takes channel coding into account and obtains a preemptively protected representation. Our implementation is based on repetition codes, adapted to the channel condition, and improves the PSNR significantly. The optimization requires an estimate of the packet loss rate at the encoder and shows moderate sensitivity to estimation errors.
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| 4. |
- Burk, Anne-Maud, et al.
(författare)
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Early Complementopathy After Multiple Injuries in Humans.
- 2012
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Ingår i: Shock. - 1540-0514. ; 37:4, s. 348-354
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: After severe tissue injury, innate immunity mounts a robust systemic inflammatory response. However, little is known about the immediate impact of multiple trauma on early complement function in humans. In the present study we hypothesized that multiple trauma results in immediate activation, consumption and dysfunction of the complement cascade and that the resulting severe "complementopathy" may be associated with morbidity and mortality.Therefore a prospective multicenter study with 25 healthy volunteers and 40 polytrauma patients (mean injury severity score [ISS] = 30.3 ± 2.9) was performed. After polytrauma serum was collected as early as possible at the scene, upon admission to the emergency room and 4, 12, 24, 120 and 240 hours post trauma and analysed for the complement profile. Complement hemolytic activity (CH-50) was massively reduced within the first 24 h after injury, recovered only 5 days after trauma and discriminated between lethal and non-lethal 28-day outcome. Serum levels of the complement activation products C3a and C5a were significantly elevated throughout the entire observation period and correlatedwith the severity of traumatic brain injury and survival. The soluble terminal complement complex SC5b-9 and mannose-binding lectin (MBL) showed a biphasic response after trauma. Key fluid phase inhibitors of complement, such as C4b-binding protein (C4BP) and factor I, were significantly diminished early after trauma.The present data indicate an almost synchronically rapid activation and dysfunction of complement suggesting a trauma-induced "complementopathy" early after injury. These events may participate to the impairment of the innate immune response observed after severe trauma.
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| 5. |
- Ebri Mars, David, et al.
(författare)
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GEOMETRY-BASED RANKING FOR MOBILE 3D VISUAL SEARCH USING HIERARCHICALLY STRUCTURED MULTI-VIEW FEATURES
- 2015
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Ingår i: 2015 IEEE INTERNATIONAL CONFERENCE ON IMAGE PROCESSING (ICIP). - : IEEE Computer Society. - 9781479983391 ; , s. 3077-3081
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Konferensbidrag (refereegranskat)abstract
- This paper proposes geometry-based ranking for mobile 3D visual search. It utilizes the underlying geometry of the 3D objects as well as the appearance to improve the ranking results. A double hierarchy has been embedded in the data structure, namely the hierarchically structured multi-view features for each object and a tree hierarchy from multi-view vocabulary trees. As the 3D geometry information is incorporated in the multi-view vocabulary tree, it allows us to evaluate the consistency of the 3D geometry at low computational complexity. Thus, a cost function is proposed for object ranking using geometric consistency. With that, we devise an iterative algorithm that accomplishes 3D geometry-based ranking. The experimental results show that our 3D geometry-based ranking improves the recall-datarate performance as well as the subjective ranking results for mobile 3D visual search.
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| 6. |
- Flierl, Markus
(författare)
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A l(1)-NORM PRESERVING MOTION-COMPENSATED TRANSFORM FOR SPARSE APPROXIMATION OF IMAGE SEQUENCES
- 2010
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Konferensbidrag (refereegranskat)abstract
- This paper discusses an adaptive non-linear transform for image sequences that aims to generate a l(1)-norm preserving sparse approximation for efficient coding. Most sparse approximation problems employ a linear model where images are represented by a basis and a sparse set of coefficients. In this work, however, we consider image sequences where linear measurements are of limited use due to motion. We present a motion-adaptive non-linear transform for a group of pictures that outputs common and detail coefficients and that minimizes the l(1) norm of the detail coefficients while preserving the overall l(1) norm. We demonstrate that we can achieve a smaller l(1) norm of the detail coefficients when compared to that of motion-adaptive linear measurements. Further, the decay of normalized absolute coefficients is faster than that of motion-adaptive linear measurements.
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| 7. |
- Flierl, Markus
(författare)
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Adaptive spatial wavelets for motion-compensated orthogonal video transforms
- 2009
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Ingår i: 2009 16th IEEE International Conference on Image Processing (ICIP). - : IEEE. - 9781424456536 ; , s. 1045-1048
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Konferensbidrag (refereegranskat)abstract
- This paper discusses adaptive spatial wavelets for the class of motion-compensated orthogonal video transforms. Motion-compensated orthogonal transforms (MCOT) are temporal transforms for video sequences that maintain orthonormality while permitting flexible motion compensation. Orthogonality is maintained for arbitrary integer-pixel or sub-pixel motion compensation by cascading a sequence of incremental orthogonal transforms and updating so-called scale counters for each pixel. The energy of the input pictures is accumulated in a temporal low-band while the temporal high-bands are zero if the input pictures are identical after motion compensation. For efficient coding, the temporal subbands should be further spatially decomposed to exploit the spatial correlation within each temporal subband. In this paper, we discuss adaptive spatial wavelets that maintain the orthogonal representation of the temporal transforms. Similar to the temporal transforms, they update scale counters for efficient energy concentration. The type-1 adaptive wavelet is a Haar-like wavelet. The type-2 considers three pixels at a time and achieves better energy compaction than the type-1.
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| 8. |
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| 9. |
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| 10. |
- Flierl, Markus, et al.
(författare)
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Image transform for video coding
- 2006
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Patent (populärvet., debatt m.m.)abstract
- A method is disclosed for decomposing a set of even and odd pictures into low-band and high-band pictures respectively in a image decomposing unit, in which the even picture is used by at least two prediction motion compensators on which the output signal of each prediction motion compensator is scaled according to the number of prediction motion compensators. The method includes calculating the high-band picture by subtracting from the odd picture the scaled motion-compensated signals and using the high-band picture in the at least two update motion compensators, the output signal of each update motion compensator being scaled according to the number of update motion compensators. Finally, the low-band picture is calculated by adding the scaled update motion-compensated signals to the even picture.
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