BEVControl: Accurately Controlling Street-view Elements with Multi-perspective Consistency via BEV Sketch Layout

Using synthesized images to boost the performance of perception models is a long-standing research challenge in computer vision. It becomes more eminent in visual-centric autonomous driving systems with multi-view cameras as some long-tail scenarios can never be collected. Guided by the BEV segmentation layouts, the existing generative networks seem to synthesize photo-realistic street-view images when evaluated solely on scene-level metrics. However, once zoom-in, they usually fail to produce accurate foreground and background details such as heading. To this end, we propose a two-stage generative method, dubbed BEVControl, that can generate accurate foreground and background contents. In contrast to segmentation-like input, it also supports sketch style input, which is more flexible for humans to edit. In addition, we propose a comprehensive multi-level evaluation protocol to fairly compare the quality of the generated scene, foreground object, and background geometry. Our extensive experiments show that our BEVControl surpasses the state-of-the-art method, BEVGen, by a significant margin, from 5.89 to 26.80 on foreground segmentation mIoU. In addition, we show that using images generated by BEVControl to train the downstream perception model, it achieves on average 1.29 improvement in NDS score.Comment: 13 pages, 8 figure

Customizing the promotion strategies of integrated air-bus service based on passenger satisfaction

The integrated air-bus service expands the catchment area and alleviates congestion of regional airports. To gain further insights into the unexplored potential attributes of the integrated service that generate passenger satisfaction, this paper utilizes a two-stage analysis approach to identify the key promotion factors for passengers from different constituents. Based on the survey data collected in Nanjing Lukou International Airport, this paper 1) uses k-means clustering to categorize respondents into four groups. 2) Combines the gradient boosting decision tree and impact asymmetry analysis to identify the attributes that have nonlinear influences on the overall service satisfaction for each group respectively. Results suggest that the timetable of the airport bus is critical for all passenger groups. Interestingly, there are noticeable differences in passenger satisfaction with the accessibility, cost affordability, comfort, reliability, and integration of the integrated service, providing the basis for customizing service promotion strategies among different passenger groups and airports.</p

High-Order Spectral Finite Elements in Analysis of Collinear Wave Mixing

Implementing collinear wave mixing techniques with numerical methods to detect acoustic nonlinearity due to damage and defects is of vital importance in nondestructive examination engineering. However, numerical simulations in existing literatures are often limited due to the compromise between computational efficiency and accuracy. In order to balance the contradiction, spectral finite element (abbreviated as SFE) with 3 × 3 and 8 × 6 nodes is developed to simulate collinear wave mixing for 1D and 2D cases in this study. The comparisons among analytical solutions, experiments, finite element method (FEM), and spectral finite element method are presented to validate the feasibility, efficiency, and accuracy of the proposed SFEs. The results demonstrate that the proposed SFEs are capable of increasing computational efficiency by as much as 14 times while maintaining the same accuracy in comparison with FEM. In addition, five 3 × 3 nodes’ SFEs or one 8 × 6 nodes’ SFE per the shortest wavelength is sufficient to capture mixing waves. Finally, the proposed 8 × 6 nodes’ SFE is recommended for collinear wave mixing to detect damage, which can offer more accuracy with similar efficiency compared to 3 × 3 nodes’ SFE

Xenotime-type high-entropy (Dy1/7Ho1/7Er1/7Tm1/7Yb1/7Lu1/7Y1/7)PO4: A promising thermal/environmental barrier coating material for SiCf/SiC ceramic matrix composites

Rare-earth phosphates (REPO4) are regarded as one of the promising thermal/environmental barrier coating (T/EBC) materials for SiCf/SiC ceramic matrix composites (SiC-CMCs) owing to their excellent resistance to water vapor and CaO–MgO–Al2O3–SiO2 (CMAS). Nevertheless, a relatively high thermal conductivity (κ) of the REPO4 becomes the bottleneck for their practical applications. In this work, novel xenotime-type high-entropy (Dy1/7Ho1/7Er1/7Tm1/7Yb1/7Lu1/7Y1/7)PO4 (HE (7RE1/7)PO4) has been designed and synthesized for the first time to solve this issue. HE (7RE1/7)PO4 with a homogeneous rare-earth element distribution exhibits high thermal stability up to 1750 ℃ and good chemical compatibility with SiO2 up to 1400 ℃. In addition, the thermal expansion coefficient (TEC) of HE (7RE1/7)PO4 (5.96×10−6 ℃−1 from room temperature (RT) to 900 ℃) is close to that of the SiC-CMCs. What is more, the thermal conductivities of HE (7RE1/7)PO4 (from 4.38 W·m−1·K−1 at 100 ℃ to 2.25 W·m−1·K−1 at 1300 ℃) are significantly decreased compared to those of single-component REPO4 with the minimum value ranging from 9.90 to 4.76 W·m−1·K−1. These results suggest that HE (7RE1/7)PO4 has the potential to be applied as the T/EBC materials for the SiC-CMCs in the future

Effect of Thickness, Density and Cavity Depth on the Sound Absorption Properties of Wool Boards

A novel wool absorption board was prepared by using a traditional non-woven technique with coarse wools as the main raw material mixed with heat binding fibers. By using the transfer-function method and standing wave tube method, the sound absorption properties of wool boards in a frequency range of 250-6300 Hz were studied by changing the thickness, density, and cavity depth. Results indicated that wool boards exhibited excellent sound absorption properties, which at high frequencies were better than that at low frequencies. With increasing thickness, the sound absorption coefficients of wool boards increased at low frequencies and fluctuated at high frequencies. However, the sound absorption coefficients changed insignificantly and then improved at high frequencies with increasing density. With increasing cavity depth, the sound absorption coefficients of wool boards increased significantly at low frequencies and decreased slightly at high frequencies

Using agricultural residue sustainably: Enhancing asphalt properties with rice husk ash and analyzing its mixture performance using response surface methodology

The employment of agricultural waste in asphalt pavement has been advocated by scientists as a strategy for raising waste recycling proportions, conserving natural resources, and handling disposal difficulties. Rice husk is an agricultural waste product with a large volume that is often incinerated for energy generation or as a means of disposal. This study conducted an investigation into the impact of rice husk ash (RHA) on the physical performance properties of asphalt binder, which included parameters such as penetration, softening point, viscosity, ductility, and storage stability, along with several temperature performance indexes. The effect of RHA and asphalt concentrations on the strength and volumetric properties of the asphalt mixture was subsequently explored through the application of response surface methodology (RSM). The compacted mixtures were subjected to Marshall stability, flow, and indirect tensile strength (ITS) tests. Subsequently, the study analyzed the effects of preparation factors using RSM with the central composite design (CCD) approach. Mathematical modeling was then carried out to predict the responses. In addition, the microstructure of the modifier and modified asphalt was examined using a scanning electron microscope (SEM). Based on the findings, the inclusion of RHA was observed to have a significant beneficial impact on the physical properties of the asphalt. Additionally, it was observed that asphalt binders could be effectively modified using up to 10% RHA, without encountering any phase separation problems during high-temperature storage. The RSM analysis indicated that changes in the preparation factors significantly influenced the flow, stability, and tensile strength of the asphalt mixture as well as its volumetric properties. The proposed models demonstrated significant agreement with the empirical findings, demonstrating a substantial correlation. Additionally, the numerical optimization findings indicated that the optimal mixture proportions to achieve the desired maximum responses were 7.6% RHA and 5.3% asphalt content

Cellulose Dissolution and InSitu Grafting in a Reversible System using an Organocatalyst and Carbon Dioxide

Cellulose is a promising renewable material, but cannot easily be processed homogeneously owing to the stiffness of the molecules and the dense packing of its chains, due to intermolecular hydrogen bonds. Cellulose processability can be improved by chemical modification. The reversible reaction of cellulose with carbon dioxide in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) allows dissolution of cellulose in dimethyl sulfoxide (DMSO). This DMSO solution is an effective medium for grafting l-lactide (LLA) from cellulose by ring-opening polymerization (ROP) under mild conditions, allowing to prepare cellulose-graft-poly(l-lactide) co-polymers with a molar substitution (MSPLLA) of poly(l-lactide) in the range of 0.37-5.32, at 80 degrees C. This makes DBU not only an important reagent to achieve cellulose dissolution, but it also acts as organocatalyst for the subsequent ring-opening polymerization process. Characterization of the structure and thermal properties of the co-polymers by a variety of techniques reveals that they have a single glass-transition temperature (T-g), which decreases with increasing MSPLLA. Thus, the modification results in a transformation of the originally semirigid cellulose into a thermoplastic material with tunable T-g. The carbon dioxide dissolution strategy is an efficient platform for cellulose derivatization by homogeneous organocatalysis