686 research outputs found
Wall heat flux in a supersonic shock wave/turbulent boundary layer interaction
No full textThe characteristics of wall heat flux (WHF) beneath a supersonic turbulent boundary layer interacting with an impinging shock wave with a 33.2 degrees angle at Mach 2.25 are analyzed using direct numerical simulation. It is found that the QP85 scaling, defined as the ratio of the mean WHF and wall pressure, changes across the interaction. The probability density function of the WHF fluctuations normalized by the local root-mean-squared value is similar to that of wall shear stress. Comparing the WHF and wall pressure spectra shows that the low-frequency shock unsteadiness exhibits little influence on the spectrum. The space-time correlation of the fluctuating WHF reveals that both the streamwise correlation length scale and the convection velocity experience a sharp decrease in the separation region and subsequent recovery in the downstream region. Moreover, the mean WHF in an incident shock interaction is decomposed for the first time. An analysis of the velocity and temperature fluctuations based on bidimensional empirical mode decomposition is performed to evaluate the contribution of turbulent structures with specific spanwise length scales to the mean WHF generation. The decomposed results indicate that the contribution associated with the large-scale structures in the outer region is greatly amplified by the shock interaction and has the leading role in the generation downstream of the interaction. Published under an exclusive license by AIP Publishin
Multiple scale sharing faster-RCNN
No full textThe student, Siwei Tang, submitted this Thesis for approval on 2019-04-24 at 10:10.This Thesis was approved for publication on 2019-04-24 at 13:17.DSpace SAF Submission Ingestion Package generated from Vireo submission #13771 on 2019-08-22 at 16:23:20Made available in DSpace on 2019-08-23T20:48:20Z (GMT). No. of bitstreams: 2
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Previous issue date: 2019-04-24Embargo set by: Seth Robbins for item 112352
Lift date: 2021-08-23T20:48:32Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 112352 on 2021-08-24T09:15:10Z.Small object detection is a challenging task in the field of computer vision because the objects are always of low resolution in the original image and can be easily affected by noise. The state-of-the-art Faster RCNN object detector has good capacity of detecting large objects while small object detection is not one of its advantages. This thesis presents a novel object detector Multi-Scale Sharing Faster-RCNN (MSS-FRCNN) to solve the problem of poor detection performance of small objects by Faster RCNN. We find that upsampling the input image can benefit the small object detection performance. So MSS-FRCNN takes two images with different scales as input and then uses the two feature maps extracted from two images for RoI generation independently. Finally, the model merges the two feature map for classification and bounding box regression. We test our model with two datasets Tsinghua-Tencent 100k and Pascal VOC 07+12. The result demonstrates that MSS-FRCNN can outperform original Faster RCNN in small object detection.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-05-01The student, Siwei Tang, accepted the attached license on 2019-04-24 at 09:11
endeneon/PICALM_Kozlova: 1.0.0 for review purpose Zenodo push
No full text<p>Scripts used in Kozlova A et al., 2024.
This repository includes code generated by Siwei Zhang (Duan lab) and Xiaotong Sun (He Lab).</p>
Passively Mode-Locked Quantum-Well Laser With a Saturable Absorber Having Gradually Varied Bandgap
No full textBook review: The US financial crisis: analysis andinterpretation: lessons for China
No full textCheng Siwei evaluates the effects of China’s countermeasures to the financial crisis and identifies the excessive growth of ‘fictitious capital’, a concept developed by Karl Marx, as its root cause. Joel Suss finds that while the author does provide excellent economic policy advice, he does not spell out policies that may shore up credibility and stop panic from spreading
Tagging Like Humans: Diverse and Distinct Image Annotation
No full textIn this work we propose a new automatic image annotation model, dubbed diverse and distinct image annotation (D2IA). The generative model D2IA is inspired by the ensemble of human annotations, which create semantically relevant, yet distinct and diverse tags. In D2IA, we generate a relevant and distinct tag subset, in which the tags are relevant to the image contents and semantically distinct to each other, using sequential sampling from a determinantal point process (DPP) model. Multiple such tag subsets that cover diverse semantic aspects or diverse semantic levels of the image contents are generated by randomly perturbing the DPP sampling process. We leverage a generative adversarial network (GAN) model to train D2IA. Extensive experiments including quantitative and qualitative comparisons, as well as human subject studies, on two benchmark datasets demonstrate that the proposed model can produce more diverse and distinct tags than the state-of-the-arts.This work is supported by Tencent AI Lab. The participation of Bernard Ghanem is supported by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research. The participation of Siwei Lyu is partially supported by National Science Foundation National Robotics Initiative (NRI) Grant (IIS-1537257) and National Science Foundation of China Project Number 61771341
Evanescently Coupled Waveguide InGaAs UTC-PD having an over 21 GHz Bandwidth under Zero Bias
No full text
Analysis and Research on the Regional Adaptability of Sponge City
No full textBased on the three values of per capita water resources, precipitation, and sewage and wastewater discharge, our country’s cities are divided into three types: water resource shortage, water quality shortage, and water pollution and water-logging risk cities. Comparing these three kinds of sponge cities, combining with the regional differences of my country’s first-tier, new first-tier and second-tier cities, determine the types of sponge cities in my country’s important cities. In view of the different water problems of the three types of cities, the regional adaptive construction plan of sponge cities is summarized
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