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| 2. |
- Kristan, Matej, et al.
(författare)
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The Visual Object Tracking VOT2015 challenge results
- 2015
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Ingår i: Proceedings 2015 IEEE International Conference on Computer Vision Workshops ICCVW 2015. - : IEEE. - 9780769557205 ; , s. 564-586
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge 2015, VOT2015, aims at comparing short-term single-object visual trackers that do not apply pre-learned models of object appearance. Results of 62 trackers are presented. The number of tested trackers makes VOT 2015 the largest benchmark on short-term tracking to date. For each participating tracker, a short description is provided in the appendix. Features of the VOT2015 challenge that go beyond its VOT2014 predecessor are: (i) a new VOT2015 dataset twice as large as in VOT2014 with full annotation of targets by rotated bounding boxes and per-frame attribute, (ii) extensions of the VOT2014 evaluation methodology by introduction of a new performance measure. The dataset, the evaluation kit as well as the results are publicly available at the challenge website(1).
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| 3. |
- Aad, G, et al.
(författare)
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- 2015
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swepub:Mat__t
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| 4. |
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| 5. |
- Liu, Y., et al.
(författare)
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Recent enhancement of central Pacific El Nino variability relative to last eight centuries
- 2017
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The far-reaching impacts of central Pacific El Nino events on global climate differ appreciably from those associated with eastern Pacific El Nino events. Central Pacific El Nino events may become more frequent in coming decades as atmospheric greenhouse gas concentrations rise, but the instrumental record of central Pacific sea-surface temperatures is too short to detect potential trends. Here we present an annually resolved reconstruction of NINO4 sea-surface temperature, located in the central equatorial Pacific, based on oxygen isotopic time series from Taiwan tree cellulose that span from 1190 AD to 2007 AD. Our reconstruction indicates that relatively warm Nino4 sea-surface temperature values over the late twentieth century are accompanied by higher levels of interannual variability than observed in other intervals of the 818-year-long reconstruction. Our results imply that anthropogenic greenhouse forcing may be driving an increase in central Pacific El Nino-Southern Oscillation variability and/or its hydrological impacts, consistent with recent modelling studies.
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| 6. |
- Ren, Guo-dong, et al.
(författare)
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Formation and temporal evolution of modulated structure in high Nb-containing lamellar gamma-TiAl alloy
- 2019
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Ingår i: Acta Materialia. - : PERGAMON-ELSEVIER SCIENCE LTD. - 1359-6454 .- 1873-2453. ; 165, s. 215-227
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Tidskriftsartikel (refereegranskat)abstract
- The formation and temporal evolution of the modulated structure in a lamellar gamma-based Ti-45Al-8.5Nb alloy have been investigated by transmission electron microscopy (TEM) in combination with first-principles theory in this work. The results show that the Nb-rich O phase as a constituent of the modulated structure is thermodynamically stable below 650 degrees C in the alpha(2) lamellae. The morphology of the O phase variants changes from thin plate-like shape with a low volume fraction at initial annealing to rectangle/square shape with a high volume fraction after a prolonged annealing, and the retransformed alpha(2), named as alpha(2-II) hereafter, emerges at intersections of the variants with two orthogonal habit planes due to their elastic interactions. The partitioning coefficient of Nb between the O phase and alpha(2) is about 2 at 600 degrees C. The diffusion coefficient of Nb derived from growth kinetics of the O phase is about (1.3 +/- 0.2) x 10(-22) m(2)s(-1) in the alpha(2) lamellae. Significant precipitation hardening effect of the O phase has been revealed for the alpha(2) lamellae and gamma/(alpha(2)+O) lamellar microstructure, which is supposed to be attributed to refining the alpha(2) lamellae associated with elastic strain energy from the alpha(2) -> O phase transformation and introducing the interface between the modulated lamella and adjacent gamma phase. All rights reserved.
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| 7. |
- Wang, Jiao, et al.
(författare)
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Fabrication and whispering gallery resonance of self-rolled up gallium nitride microcavities
- 2017
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Ingår i: Thin Solid Films. - : ELSEVIER SCIENCE SA. - 0040-6090 .- 1879-2731. ; 627, s. 77-81
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Tidskriftsartikel (refereegranskat)abstract
- The C-plane monocrystalline GaN/ZnO thin film epitaxially grows on A-plane sapphire substrate by molecular beam epitaxy (MBE) is revealed by the reflection high-energy electron diffraction (RHEED). The monocrystalline GaN nanomembranes have been rolled up into tubular microstructures as whispering gallery microcavities, which support the whisper gallery modes (WGMs) in the violet and blue regime. The WGMs of the rolled-up monocrystalline GaN devices are tunable with microtube diameter by tuning the strain gradient of the GaN nanomembranes. This approach could help with not only the further development of GaN-based photonic devices, but also the physical understanding of other rolled-up optical microcavities.
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| 8. |
- Wang, L., et al.
(författare)
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Exploiting Full Duplex for Device-to-Device Communications in Heterogeneous Networks
- 2015
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Ingår i: IEEE Communications Magazine. - 0163-6804 .- 1558-1896. ; 53:5, s. 146-152
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we discuss full duplex for heterogenous networks that accommodate the coexistence of device-to-device communications. The short link distance and lower transmit power of device-to-device communications make them excellent candidates to exploit full duplex inband transmission. By incorporating power allocation for self-interference cancellation based on antenna isolation, analog cancellation, and digital cancellation, full-duplex device-to-device, FD-D2D, nodes can potentially improve spectrum efficiency in HetNets. We provide a comprehensive overview on FD-D2D communications in HetNets. Additionally, we identify several challenges, provide potential solutions to interference mitigation based on power control, beamforming, and resource scheduling, and further discuss applications of FD in 5G networks.
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| 9. |
- Wang, Xiang-Gao, et al.
(författare)
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HOW BAD OR GOOD ARE THE EXTERNAL FORWARD SHOCK AFTERGLOW MODELS OF GAMMA-RAY BURSTS?
- 2015
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Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 219:1
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Tidskriftsartikel (refereegranskat)abstract
- The external forward shock models have been the standard paradigm to interpret the broadband afterglow data of gamma-ray bursts (GRBs). One prediction of the models is that some afterglow temporal breaks at different energy bands should be achromatic; that is, the break times should be the same in different frequencies. Multiwavelength observations in the Swift era have revealed chromatic afterglow behaviors at least in some GRBs, casting doubts on the external forward shock origin of GRB afterglows. In this paper, using a large sample of GRBs with both X-ray and optical afterglow data, we perform a systematic study to address the question: how bad or good are the external forward shock models? Our sample includes 85 GRBs up to 2014 March with well-monitored X-ray and optical light curves. Based on how well the data abide by the external forward shock models, we categorize them into five grades and three samples. The first two grades (Grade I and II) include 45 of 85 GRBs. They show evidence of, or are consistent with having, an achromatic break. The temporal and spectral behaviors in each afterglow segment are consistent with the predictions (the "closure relations") of the forward shock models. These GRBs are included in the Gold sample. The next two grades (Grade III and IV) include 37 of 85 GRBs. They are also consistent with having an achromatic break, even though one or more afterglow segments do not comply with the closure relations. These GRBs are included in the Silver sample. Finally, Grade V (3/85) shows direct evidence of chromatic behaviors, suggesting that the external shock models are inconsistent with the data. These are included in the Bad sample. We further perform statistical analyses of various observational properties (temporal index alpha, spectral index beta, break time t(b)) and model parameters (energy injection index q, electron spectral index p, jet opening angle theta(j), radiative efficiency eta(gamma), and so on) of the GRBs in the Gold sample, and derive constraints on the magnetization parameter epsilon(B) in the forward shock. Overall, we conclude that the simplest external forward shock models can account for the multiwavelength afterglow data of at least half of the GRBs. When more advanced modeling (e.g., long-lasting reverse shock, structured jets, arbitrary circumburst medium density profile) is invoked, up to >90% of the afterglows may be interpreted within the framework of the external shock models.
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| 10. |
- Wei, Qing, et al.
(författare)
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Resource allocation for V2X communications: A local search based 3D matching approach
- 2017
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Ingår i: IEEE International Conference on Communications. - 1550-3607. - 9781467389990
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Konferensbidrag (refereegranskat)abstract
- Vehicle-to-everything (V2X) communications, en- abled by cellular device-to-device (D2D) links, have recently drawn much attention due to its potential to improve traffic safety, efficiency, and comfort. In this context, however, intracell interference combined with demanding latency and reliability requirements of safety vehicular users (V-UEs) are challenging issues. In this paper, we study a resource allocation problem among safety V-UEs, non-safety V-UEs, and conventional cellular UEs (C-UEs). Firstly, the resource allocation problem is formulated as a three-dimensional matching problem, where the objective is to maximize the total throughput of non-safety V-UEs on condition of satisfying the requirements on C-UEs and on safety V-UEs. Due to its NP-hardness, we then exploit hypergraph theory and propose a local search based approximation algorithm to solve it. Through simulation results, we show that the proposed algorithm outperforms the existing scheme in terms of both throughput performance and computational complexity.
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