| 1. |
- Ge, Chenjie, 1991, et al.
(author)
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Co-saliency detection via similarity-based saliency propagation
- 2015
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In: 2015 IEEE International Conference on Image Processing (ICIP). ; , s. 1845 - 1849
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Conference paper (peer-reviewed)abstract
- In this paper, we present a method for discovering the common salient objects from a set of images. We treat co-saliency detection as a pairwise saliency propagation problem, which utilizes the similarity between each pair of images to measure the common property with the guidance of a single saliency map image. Given the pairwise co-salient foreground maps, pairwise saliency is optimized by combining the initial background cues. Pairwise co-salient maps are then fused according to a novel fusion strategy based on the focus of human attention. Finally we adopt an integrated multi-scale scheme to obtain the pixel-level saliency map. Our proposed model makes the existing single saliency model perform well in co-saliency detection and is not overly sensitive to the initial saliency model selected. Extensive experiments on two benchmark databases show the superiority of our co-saliency model against the state-of-the-art methods both subjectively and objectively.
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| 2. |
- Hudson, Thomas J., et al.
(author)
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International network of cancer genome projects
- 2010
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 464:7291, s. 993-998
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Journal article (peer-reviewed)abstract
- The International Cancer Genome Consortium (ICGC) was launched to coordinate large-scale cancer genome studies in tumours from 50 different cancer types and/or subtypes that are of clinical and societal importance across the globe. Systematic studies of more than 25,000 cancer genomes at the genomic, epigenomic and transcriptomic levels will reveal the repertoire of oncogenic mutations, uncover traces of the mutagenic influences, define clinically relevant subtypes for prognosis and therapeutic management, and enable the development of new cancer therapies.
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| 3. |
- Li, Ruiyun, et al.
(author)
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Operando Formation of Van der Waals Heterostructures for Achieving Macroscale Superlubricity on Engineering Rough and Worn Surfaces
- 2022
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In: Advanced Functional Materials. - : John Wiley & Sons. - 1616-301X .- 1616-3028. ; 32:18
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Journal article (peer-reviewed)abstract
- Macroscale superlubricity breakdown of lubricating materials caused by substrate surface roughening and mechanochemical modification poses great challenges for their practical tribological applications. Here, a facile way is reported to access robust macroscale superlubricity in a vacuum environment, via the operando formation of graphene/transition-metal dichalcogenide (TMDC) heterostructures at wear-induced rough surfaces. By trapping active amorphous carbon (a-C) wear products between TMDC flakes, the sandwich structures readily transform into graphene/TMDC heterostructures during running-in stage, based on shear-induced confinement and load-driven graphitization effects. Then they assemble into multipoint flake-like tribofilms to achieve macroscale superlubricity at steady stage by reducing contact area, eliminating strong cross-interface carbon–carbon interactions and polishing a-C rough nascent surface. Atomistic simulations reveal the preferential formation of graphene/TMDC heterostructures during running-in stage and demonstrate the superlubric sliding of TMDCs on the graphene. The findings are of importance to achieve robust superlubricity and provide a good strategy for the synthesis of other van der Waals heterostructures.
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| 4. |
- Zhang, Yumeng, et al.
(author)
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Effects of ionic hydration and hydrogen bonding on flow resistance of ionic aqueous solutions confined in molybdenum disulfide nanoslits : Insights from molecular dynamics simulations
- 2019
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In: Fluid Phase Equilibria. - : Elsevier. - 0378-3812 .- 1879-0224. ; 489, s. 23-29
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Journal article (peer-reviewed)abstract
- Single-layer molybdenum disulfide (MoS2) is a novel two-dimensional material that has attracted considerable attention because of its excellent properties. In this work, molecular dynamics simulations were performed to investigate the effect of different kinds of alkali metal ions (Li+, Na+, and K+) on the flow resistance of ionic aqueous solutions confined in MoS2 nanoslits under shearing. Three slit widths (i.e. 1.2, 1.6, and 2.0 nm) were investigated. Simulation results showed that the friction coefficient followed the order of K+ < Na+ < Li+. The friction coefficient decreased with the increasing of slit width. Unique confined spatial distributions of different types of ionic aqueous solutions led to different confined ionic hydrations for different cations. These differences lead to different orientations of surrounding water molecules and then form different hydrogen bond (HB) networks. The friction coefficient was greatly dependent on the number of HBs per water; i.e., the larger the number of HBs formed, the lower was the flow resistance.
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| 5. |
- Chen, Jun, et al.
(author)
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A self-healing elastomer based on an intrinsic non-covalent cross-linking mechanism
- 2019
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In: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488. ; 7:25, s. 15207-15214
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Journal article (peer-reviewed)abstract
- Synthesis and comprehensive examination of a polyurethane (urea) elastomer that self-heals based on intrinsic dynamic non-covalent bonds (van der Waals and hydrogen) are reported. The dynamic non-covalent bonds include hydrogen bonds and van der Waals forces. The difference in the previous approach in which hydrogen bond self-healing materials introduced dense quadruple hydrogen bonds at the ends or branched chains poly(propylene carbonate) (PPC) diol was used as the soft segment of the polyurethane (urea) material, and strong van der Waals forces were provided by the large number of carbonyl groups in its main chain; hydrogen bonds were formed by urethane bonds, urea bonds, and the carbonyl groups on PPC. The mechanical properties and healing efficiency of the self-healing polyurethane (urea) elastomer were studied. In situtemperature-dependent infrared and low-field nuclear magnetic resonance (LNMR) measurements were combined with molecular dynamics simulations to investigate the self-healing mechanisms. The results of the studies on the self-healing polyurethane demonstrate that the dynamic cross-linking between hydrogen bonds and van der Waals forces is the basic driving force for the self-healing ability of the material, and temperature is the key factor that affects hydrogen bonding and van der Waals forces. The effect of crystallization on the self-healing ability of the material was also studied. The molecular dynamics simulation results also demonstrate interplay between van der Waals forces and hydrogen bonds at different temperatures.
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| 6. |
- Chen, Yicheng, et al.
(author)
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Computational fluid-structure interaction analysis of flapping uvula on aerodynamics and pharyngeal vibration in a pediatric airway
- 2023
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In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 13:1, s. 2013-
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Journal article (peer-reviewed)abstract
- The uvula flapping is one of the most distinctive features of snoring and is critical in affecting airway aerodynamics and vibrations. This study aimed to elucidate the mechanism of pharyngeal vibration and pressure fluctuation due to uvula flapping employing fluid-structure interaction simulations. The followings are the methodology part: we constructed an anatomically accurate pediatric pharynx model and put attention on the oropharynx region where the greatest level of upper airway compliance was reported to occur. The uvula was assumed to be a rigid body with specific flapping frequencies to guarantee proper boundary conditions with as little complexity as possible. The airway tissue was considered to have a uniform thickness. It was found that the flapping frequency had a more significant effect on the airway vibration than the flapping amplitude, as the flapping uvula influenced the pharyngeal aerodynamics by altering the jet flow from the mouth. Breathing only through the mouth could amplify the effect of flapping uvula on aerodynamic changes and result in more significant oropharynx vibration.
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| 7. |
- Chen, Yicheng, et al.
(author)
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Evaluation of computational fluid dynamics models for predicting pediatric upper airway airflow characteristics
- 2023
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In: Medical and Biological Engineering and Computing. - : Springer. - 0140-0118 .- 1741-0444. ; 61:1, s. 259-270
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Journal article (peer-reviewed)abstract
- Computational fluid dynamics (CFD) has the potential for use as a clinical tool to predict the aerodynamics and respiratory function in the upper airway (UA) of children; however, careful selection of validated computational models is necessary. This study constructed a 3D model of the pediatric UA based on cone beam computed tomography (CBCT) imaging. The pediatric UA was 3D printed for pressure and velocity experiments, which were used as reference standards to validate the CFD simulation models. Static wall pressure and velocity distribution inside of the UA under inhale airflow rates from 0 to 266.67 mL/s were studied by CFD simulations based on the large eddy simulation (LES) model and four Reynolds-averaged Navier-Stokes (RANS) models. Our results showed that the LES performed best for pressure prediction; however, it was much more time-consuming than the four RANS models. Among the RANS models, the Low Reynolds number (LRN) SST k-ω model had the best overall performance at a series of airflow rates. Central flow velocity determined by particle image velocimetry was 3.617 m/s, while velocities predicted by the LES, LRN SST k-ω, and k-ω models were 3.681, 3.532, and 3.439 m/s, respectively. All models predicted jet flow in the oropharynx. These results suggest that the above CFD models have acceptable accuracy for predicting pediatric UA aerodynamics and that the LRN SST k-ω model has the most potential for clinical application in pediatric respiratory studies.
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| 8. |
- Chen, Yicheng, et al.
(author)
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Impact of sleep posture and breathing pattern on soft palate flutter and pharynx vibration in a pediatric airway using fluid-structure interaction
- 2023
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In: Journal of Biomechanics. - : Elsevier. - 0021-9290 .- 1873-2380. ; 152
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Journal article (peer-reviewed)abstract
- Snoring is a common condition in the general population, and the management of snoring requires a better understanding of its mechanism through a fluid-structure interaction (FSI) perspective. Despite the recent popularity of numerical FSI techniques, outstanding challenges are accurately predicting airway deformation and its vibration during snoring due to complex airway morphology. In addition, there still needs to be more un-derstanding of snoring inhibition when lying on the side, and the possible effect of airflow rates, as well as nose or mouth-nose breathing, on snoring remains to be investigated. In this study, an FSI method verified against in vitro models was introduced to predict upper airway deformation and vibration. The technique was applied to predict airway aerodynamics, soft palate flutter, and airway vibration in four sleep postures (supine, left/right lying, and sitting positions) and four breathing patterns (mouth-nose, nose, mouth, and unilateral nose breathing). It was found that, at given elastic properties of soft tissues, the evaluated flutter frequency of 19.8 Hz in inspiration was in good agreement with the reported frequency of snoring sound in literature. Reduction in flutter and vibrations due to the mouth-nose airflow proportion changes were also noticed when having side-lying and sitting positions. Breathing through the mouth results in larger airway deformation than breathing through the nose or mouth-nose. These results collectively demonstrate the potential of FSI for studying the physics of airway vibration and clarify to some degree the reason for snoring inhibition during sleep postures and breathing patterns.
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| 9. |
- Du, Xiaoyu, et al.
(author)
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The porous cantilever beam as a model for spinal implants : Experimental, analytical and finite element analysis of dynamic properties
- 2023
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In: Mathematical Biosciences and Engineering. - : American Institute of Mathematical Sciences. - 1547-1063 .- 1551-0018. ; 20:4, s. 6273-6293
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Journal article (peer-reviewed)abstract
- Investigation of the dynamic properties of implants is essential to ensure safety and compatibility with the host's natural spinal tissue. This paper presents a simplified model of a cantilever beam to investigate the effects of holes/pores on the structures. Free vibration test is one of the most effective methods to measure the dynamic response of a cantilever beam, such as natural frequency and damping ratio. In this study, the natural frequencies of cantilever beams made of polycarbonate (PC) containing various circular open holes were investigated numerically, analytically, and experimentally. The experimental data confirmed the accuracy of the natural frequencies of the cantilever beam with open holes calculated by finite element and analytical models. In addition, two finite element simulation methods, the dynamic explicit and modal dynamic methods, were applied to determine the damping ratios of cantilever beams with open holes. Finite element analysis accurately simulated the damped vibration behavior of cantilever beams with open holes when known material damping properties were applied. The damping behavior of cantilever beams with random pores was simulated, highlighting a completely different relationship between porosity, natural frequency and damping response. The latter highlights the potential of finite element methods to analyze the dynamic response of arbitrary and complex structures, towards improved implant design.
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| 10. |
- Fu, Keren, 1988, et al.
(author)
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Adaptive Multi-Level Region Merging for Salient Object Detection
- 2014
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In: British Machine Vision Conference (BMVC) 2014. ; , s. 11 -
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Conference paper (peer-reviewed)abstract
- Most existing salient object detection algorithms face the problem of either under or over-segmenting an image. More recent methods address the problem via multi-level segmentation. However, the number of segmentation levels is manually predetermined and only works well on specific class of images. In this paper, a new salient object detection scheme is presented based on adaptive multi-level region merging. A graph based merging scheme is developed to reassemble regions based on their shared contourstrength. This merging process is adaptive to complete contours of salient objects that can then be used for global perceptual analysis, e.g., foreground/ground separation. Such contour completion is enhanced by graph-based spectral decomposition. We show that even though simple region saliency measurements are adopted for each region, encouraging performance can be obtained after across-level integration. Experiments by comparing with 13 existing methods on three benchmark datasets including MSRA-1000, SOD and SED show the proposed method results in uniform object enhancement and achieves state-of-the-art performance.
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