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- Kristanl, Matej, et al.
(författare)
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The Seventh Visual Object Tracking VOT2019 Challenge Results
- 2019
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Ingår i: 2019 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW). - : IEEE COMPUTER SOC. - 9781728150239 ; , s. 2206-2241
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2019 is the seventh annual tracker benchmarking activity organized by the VOT initiative. Results of 81 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in the recent years. The evaluation included the standard VOT and other popular methodologies for short-term tracking analysis as well as the standard VOT methodology for long-term tracking analysis. The VOT2019 challenge was composed of five challenges focusing on different tracking domains: (i) VOT-ST2019 challenge focused on short-term tracking in RGB, (ii) VOT-RT2019 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2019 focused on long-term tracking namely coping with target disappearance and reappearance. Two new challenges have been introduced: (iv) VOT-RGBT2019 challenge focused on short-term tracking in RGB and thermal imagery and (v) VOT-RGBD2019 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2019, VOT-RT2019 and VOT-LT2019 datasets were refreshed while new datasets were introduced for VOT-RGBT2019 and VOT-RGBD2019. The VOT toolkit has been updated to support both standard short-term, long-term tracking and tracking with multi-channel imagery. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The dataset, the evaluation kit and the results are publicly available at the challenge website(1).
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- Bao, Lei, et al.
(författare)
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A scheme for joint quantization, error protection and feedback control over noisy channels
- 2007
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Ingår i: 2007 AMERICAN CONTROL CONFERENCE, VOLS 1-13. - : IEEE. - 9781424409884 ; , s. 2456-2461
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Konferensbidrag (refereegranskat)abstract
- We study a closed-loop scalar control system with feedback transmitted over a discrete noisy channel. For this problem, we propose a joint design of the state measurement quantization, protection against channel errors, and control. The goal is to minimize a linear quadratic cost function over a finite horizon. In particular we focus on a special case where we verify that certainty equivalence holds, and for this case we design joint source-channel encoder and decoder/estimator pairs. The proposed algorithm leads to a practically feasible design of time-varying non-uniform quantization and control. Numerical results demonstrate the promising performance obtained by employing the proposed iterative optimization algorithm.
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| 7. |
- Bao, Lei, 1976-
(författare)
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Control over Low-Rate Noisy Channels
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Networked embedded control systems are present almost everywhere. A recent trendis to introduce radio communication in these systems to increase mobility and flex-ibility. Network nodes, such as the sensors, are often simple devices with limitedcomputing and transmission power and low storage capacity, so an important prob-lem concerns how to optimize the use of resources to provide sustained overall sys-tem performance. The approach to this problem taken in the thesis is to analyzeand design the communication and control application layers in an integrated man-ner. We focus in particular on cross-layer design techniques for closed-loop controlover non-ideal communication channels, motivated by future control systems withvery low-rate and highly quantized sensor communication over noisy links. Severalfundamental problems in the design of source–channel coding and optimal controlfor these systems are discussed.The thesis consists of three parts. The first and main part is devoted to the jointdesign of the coding and control for linear plants, whose state feedback is trans-mitted over a finite-rate noisy channel. The system performance is measured by afinite-horizon linear quadratic cost. We discuss equivalence and separation proper-ties of the system, and conclude that although certainty equivalence does not holdin general it can still be utilized, under certain conditions, to simplify the overalldesign by separating the estimation and the control problems. An iterative opti-mization algorithm for training the encoder–controller pairs, taking channel errorsinto account in the quantizer design, is proposed. Monte Carlo simulations demon-strate promising improvements in performance compared to traditional approaches.In the second part of the thesis, we study the rate allocation problem for statefeedback control of a linear plant over a noisy channel. Optimizing a time-varyingcommunication rate, subject to a maximum average-rate constraint, can be viewedas a method to overcome the limited bandwidth and energy resources and to achievebetter overall performance. The basic idea is to allow the sensor and the controllerto communicate with a higher data rate when it is required. One general obstacle ofoptimal rate allocation is that it often leads to a non-convex and non-linear problem.We deal with this challenge by using high-rate theory and Lagrange duality. It isshown that the proposed method gives a good performance compared to some otherrate allocation schemes.In the third part, encoder–controller design for Gaussian channels is addressed.Optimizing for the Gaussian channel increases the controller complexity substan-tially because the channel output alphabet is now infinite. We show that an efficientcontroller can be implemented using Hadamard techniques. Thereafter, we proposea practical controller that makes use of both soft and hard channel outputs.
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- Bao, Lei, et al.
(författare)
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Encoder-controller design for control over the binary-input Gaussian channel
- 2010
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Ingår i: IEEE International Symposium on Spread Spectrum Techniques and Applications. - : IEEE. - 9781424460151 ; , s. 23-28
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Konferensbidrag (refereegranskat)abstract
- In this paper, we consider the problem of the joint optimization of encoder-controller for closed-loop control with state feedback over a binary-input Gaussian channel (BGC). The objective is to minimize the expected linear quadratic cost over a finite horizon. Thisencoder-controller optimization problem is hard in general, mostly because of the curse of dimensionality. The result of this paper is a synthesis technique for a computationally feasible suboptimal controller which exploits both the soft and hard information of thechannel outputs. The proposed controller is efficient in the sense that it embraces measurement quantization, error protection and control over a finite-input infinite-output noisy channel. How to effectively implement this controller is also addressed in the paper. In particular, this is done by using Hadamard techniques. Numerical experiments are carried out to verify the promising gain offered by the combined controller, in comparison to the hard-information-based controller.
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- Bao, Lei, et al.
(författare)
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Encoder-decoder design for event-triggered feedback control over bandlimited channels
- 2006
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Ingår i: 2006 American Control Conference. - : IEEE. - 1424402093 ; , s. 4183-4188
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Konferensbidrag (refereegranskat)abstract
- Bandwidth limitations and energy constraints set severe restrictions on the design of control systems that utilize wireless sensor and actuator networks. It is common in these systems that a sensor node needs not be continuously monitored, but communicates to the controller only at certain instances when it detects a disturbance event. In this paper, such a scenario is studied and particular emphasis is on efficient utilization of the shared communication resources. Encoder-decoder design for an event-based control system with the plant affected by pulse disturbances is considered. A new iterative procedure is proposed which can jointly optimize encoder-decoder pairs for a certainty equivalent controller. The goal is to minimize a design criterion, in particular, a linear quadratic cost over a finite horizon. The algorithm leads to a feasible design of time-varying non-uniform encoder-decoder pairs. Numerical results demonstrate significant improvements in performance compared to a system using uniform quantization.
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- Bao, Lei
(författare)
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Immunomodulation and immunopathogenesis in autoimmune disease with emphasis on autoimmune neuritis and arthritis
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Experimental autoimmune neuritis (EAN) and arthritis are CD4+ T cell mediated autoimmune animal models for the study of immunomodulation and immunopathogenesis of human Guillain-Barré syndrome (GBS) and rheumatoid arthritis (RA). Inflammatory cell infiltration and cytokine production in the target organs are characteristic features of both diseases, suggesting a role of cytokine production in the pathogenesis. A significant reduction in the incidence and severity of EAN and a delayed time of onset of EAN were found in IL-12 deficient (IL-12-/-), as compared to wild type mice. The clinical symptoms were associated with a reduced IFN-gamma and TNF-alpha, while enhanced IL-4 production in the sciatic nerve as well as significantly suppressed levels of anti-PO peptide IgG2b antibody in serum suggested that IL-12 has a major role in the initiation, enhancement and perpetuation of pathogenic events in EAN by promoting a Th1 cell-mediated immune response and suppressing the Th2 response. These results demonstrate that IIL-12 may play a critical role in the pathogenesis of EAN. Tumor necrosis factor receptor I (TNFR I) is thought to mediate the majority of TNF activities. When administered soluble TNFR I (sTNFR I) to mice immunized with PO peptide the severity and the duration of EAN were decreased. This was accompanied in vitro by a marked reduction in antigen-specific T cell proliferation and IFN-gamma synthesis by spleen cells in sTNFR I treated mice. Immunohistochemical analysis revealed a strong decrease in the number of infiltrating macrophages, CD4+ T cells and CD8+ T cells in the sciatic nerve. These data directly demonstrate a pivotal role for TNF in the development of EAN and also suggest that sTNFR I may have a therapeutic potential in human GBS. CC chemokine receptor 5 deficient (CCR5-/-) mice showed a significant reduction in the incidence of collagen-induced arthritis in comparison to wild-type (CCR5+/+) mice. However, the severity score once they developed arthritis showed clinical features similar to wild-type mice. There were significantly lower levels of antibodies against CH in CCR5-/- mice compared to wild- type mice, especially IgG2a and IgG2b, and obviously higher levels of EL10 in CCR5-/- mice. There was overproduction of MIP-1beta in serum and culture supernatant of spleen cells in CCR5 deficient mice after CH-immunization that might partly have contributed to the severity of arthritis. Our results indicate that CCR5 plays a role in the pathogenesis of arthritis, but its role can probably be substituted by other factors. Changes of glia and cytokine expression were found in the spinal cord of adjuvantinduced arthritic (AIA) rats. Macroglia and MHC class 11 immunostaining were enhanced, and the numbers and immunostaining intensity of astrocytes expressing GFAP were increased. Using in situ hybridization and immunohistochemical methods, both mRNA and protein levels of IL-1beta, IL-6 and TNF-alpha were significantly increased in the spinal cord of arthritic rats. Higher levels of cytokine expression were noted in reactive astrocytes and microglia.
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