Stereo cameras have been widely used in three-dimensional (3d) reconstruction, target ranging and environment perception. The calibration of stereo cameras is the key technology of vision system. Most of the existing ...
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Stereo cameras have been widely used in three-dimensional (3d) reconstruction, target ranging and environment perception. The calibration of stereo cameras is the key technology of vision system. Most of the existing methods are not flexible due to limitations of the size of the cameras' overlapping fields of view (FOV) and the degree of defocus. This paper presents a stereo calibration method in which the feature points on the target are globally encoded by the phase-coding method. Each feature point has a specific code, and the mapping relationship between image coordinates and world coordinates can be uniquely determined. So, the stereo cameras whether or not capture the same area of the target, both the camera coordinate systems can be unified under one global coordinate system. In addition, calibration can be accomplished when cameras are out of focus seriously, for the coding and extraction of feature points are phase-based. Simulations and experiments were carried out to prove flexibility androbustness of the proposed method.
A real-time electrostatic particle sensor has been developed to measure the concentration of soot in diesel exhaust. Based on the Venturi effect, the self-priming sampling probe of the sensor was designed to generate ...
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A real-time electrostatic particle sensor has been developed to measure the concentration of soot in diesel exhaust. Based on the Venturi effect, the self-priming sampling probe of the sensor was designed to generate a pressure difference to drive particles into the detection region of the electrostatic trap. A detection module was developed forreal-time measurement of the nanoamp current generated by charged soot within the probe. The microcurrent was amplified by the signal processing system of the sensor. To guarantee the precision of particles, it was essential to test the performance. The sensor was able to measure currents from -100 nA to -30 nA with a relative error of -0.01%. In addition, experiments comparing the sensor with a commercial instrument have shown that they correlate well. Furthermore, the standarddeviation of the sensor was 0.001049 during a 36 h long-term test, which is lower than a commercial instrument with better stability. The sensor was investigated to demonstrate the detection of diesel particulate filter (dPF) failure. The results showed that the consistency between the sensor and the regulatory measurement equipment was good. The data ratios of the sensors installed at the front andrear of the dPF differed by many fold, which indicated that the sensor was able to determine the status of the exhaust system.
Landslides represent a major global natural disaster, often leading to severe consequences, including substantial loss of life and property. However, research on the spatiotemporal distribution characteristics of fata...
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Landslides represent a major global natural disaster, often leading to severe consequences, including substantial loss of life and property. However, research on the spatiotemporal distribution characteristics of fatal landslide events across different climate regions and their association with precipitation remains limited. In this study, we compiled a database of non-seismic fatal landslides in china from 2010 to 2022 to examine their spatiotemporal distribution andrelationship with precipitation. From 2010 to 2022, china experienced a total of 710 fatal landslide events, causing 5158 fatalities. The data revealed a declining trend in both the number of fatal landslides and associated fatalities, with the number of fatal landslides demonstrating a recurring cycle of 3-4 years marked by continuous decreases within each cycle. The initial year of a new cycle witnessed a significant increase in the number of fatal landslides, suggesting a periodic occurrence, which is related to El Ni & ntilde;o. The central subtropical humidregion recorded the highest number of fatal landslide events, attributed to its highest annual precipitation. The trend in fatal landslides closely corresponded with variations in precipitation, increasing in spring and summer anddecreasing in autumn and winter. The cumulative frequency distributions of fatal landslides and fatalities followed a power-law distribution, with a sharp decline observed when exceeding a certain value, indicating a deflection effect. despite the low population density, the plateau climate region has the highest risk of life loss among all climate regions. Understanding the spatial distribution of non-seismic fatal landslides can significantly aid in formulating more effective disaster prevention and mitigation policies.
Floor plan vectorization in complex scenarios poses significant challenges due to the intricate anddiverse nature of design elements. This paper capitalizes on the inherent characteristics of architectural elements, ...
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Floor plan vectorization in complex scenarios poses significant challenges due to the intricate anddiverse nature of design elements. This paper capitalizes on the inherent characteristics of architectural elements, eliminating the requirement for semantic segmentation processes. This paper proposes a method with a specially designedrepresentation, employing a quartet of points to accurately capture a wide range of shapes with minimal parameters. Furthermore, a comprehensive dataset is proposed, consisting of large-scale images that contain a significantly higher number of elements and encompass diverse floor plan styles. Experimental results demonstrate the robust performance and substantial improvement of the proposed method in boundary delineation. These results indicate the ease of parameterization and notable practical potential of the proposed method in real-world scenes.
Combining TT* argument and bilinear interpolation,this paper obtains the Strichartz and smoothing estimates of dispersive semigroup e^(-itP(d)) in weighted L^(2) *** other things,we recover the results in[1].Moreover,...
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Combining TT* argument and bilinear interpolation,this paper obtains the Strichartz and smoothing estimates of dispersive semigroup e^(-itP(d)) in weighted L^(2) *** other things,we recover the results in[1].Moreover,the application of these results to the well-posedness of some equations are shown in the last section.
Enhancing the high-speeddynamic performance and adaptive capabilities of amphibious robots in complex and amphibious environments is of utmost importance. A bioinspired paddle-wheeled leg amphibious robot that is env...
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Enhancing the high-speeddynamic performance and adaptive capabilities of amphibious robots in complex and amphibious environments is of utmost importance. A bioinspired paddle-wheeled leg amphibious robot that is environment-adaptive autonomously has been proposed anddeveloped to tackle such a challenge. The designedrobot features a composite paddle-wheeled leg structure and a switching mechanism. This design significantly improves the robot's adaptability to diverse and challenging terrains while showcasing exceptional water propulsion performance. Meanwhile, an autonomous switching of water and land modes based on torque feedback is proposed to achieve autonomous identification of land and water. Finally, we introduce a Hopf oscillator-based central pattern generator control strategy to assist the robot in transitioning to a hexapod gait effectively and smoothly after steering. Experiments are conducted to assess the robot's locomotive capabilities on various terrains. These tests have also evaluated the robot's capability to switch autonomously between land and water modes. The findings confirm the design's exceptional performance and validate its innovative features.
Understanding the residence time distribution(rTd)of a continuous hydrothermal reactor is of great significance to improve product quality andreaction *** this work,an on-line measurement system is attached to a cont...
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Understanding the residence time distribution(rTd)of a continuous hydrothermal reactor is of great significance to improve product quality andreaction *** this work,an on-line measurement system is attached to a continuous reactor to investigate the characteristics of *** approach that can accurately fit anddescribe the experimental measuredrTd curve by finding characteristic values is proposed for analysis and *** rTd curves of three experiment groups are measured and the characteristic values are *** show that increasing total flow rate and extending effective reactor length have inverse effect on average residence time,but they both cause the reactor to approach a plug flow reactor and improve the materials *** branch flow rate fraction has no significant effect on rTd characteristics in the scope of the present work except the weak negative correlation with the average residence ***,the natural convection stirring effect can also increase the average residence time,especially when the forced flow is *** analysis reveals that it is necessary to consider the matching of natural convection,forced flow andreactor size to control rTd when designing the hydrothermal reactor and working conditions.
The study focused on constructing a machine learning model, considering the interaction of alloying elements on corrosion resistance of low alloy steels in the marine atmospheric environment. Spearman's analysis w...
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The study focused on constructing a machine learning model, considering the interaction of alloying elements on corrosion resistance of low alloy steels in the marine atmospheric environment. Spearman's analysis was applied, and the relationship between alloying element and corrosion rate was evaluated based on random forest (rF) importance and Shapley additive explanation (SHAP) analysis. The prediction performance of the six models (rF, multilayer perceptron (MLP), ridge regression (rr), K-nearest neighborregression (KNN), logistic regression (Lr), and support vector machine (SVM) was compared by using the preferreddominant elements as input variables. Afterwards, a high-precision corrosion rate prediction model based on rF was constructed. Finally, the generalizability of the model was demonstrated using 10 lines of steel corrosion data from several new marine atmospheric environments.
This study was to establish an efficient strategy based on inoculum-morphology control for the submerged mycelial fermentation of an edible and medicinal fungus, Inonotus hispidus. Two major morphological forms of the...
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This study was to establish an efficient strategy based on inoculum-morphology control for the submerged mycelial fermentation of an edible and medicinal fungus, Inonotus hispidus. Two major morphological forms of the mycelial inoculum were compared, dispersed mycelial fragments versus aggregated mycelial clumps. The dispersed one was more favorable for the fermentation, starting with a shorter lag period and attaining a higher biomass yield and more uniform mycelium pellets in shake flasks. The mycelial pellets taken from the shake flask culture on day 6 were fragmented at 26,000 rpm in a homogenizer, and a shear time of 3 min provided the optimal inoculum. The inoculum and culture conditions were further verified in 5-L stirred tank fermenters and then the fermentation was scaled-up in a 100-L stirred tank. With the optimized inoculum and process conditions plus a fed-batch operation, much higher productivities, including 22.23 g/L biomass, 3.31 g/L EPS, and 5.21 g/L IPS, were achieved in the 100-L fermenter than in the flask culture. A composition analysis showed that the I. hispidus mycelium produced by the fermentation was rich in protein, dietary fiber, and polysaccharides which may be beneficial to health. Overall, the results have shown that the inoculum characteristics including age, morphology, and state of aggregation have significant impact on the productivity of mycelial biomass and polysaccharides in a submerged mycelial fermentation of the I. hispidus fungus.
The inverse design of solid-state materials with targeted properties represents a significant challenge in materials science, particularly for piezoelectric semiconductors where both structural symmetry and electronic...
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The inverse design of solid-state materials with targeted properties represents a significant challenge in materials science, particularly for piezoelectric semiconductors where both structural symmetry and electronic properties must be carefully controlled. Here, we employ the simplified line-input crystal-encoding system representation combined with the MatterGPT framework fordiscovering potential piezoelectric semiconductors. By training on a curateddataset of 1556 piezoelectric materials from the Materials Project database, our model learns to generate crystal structures with targeted piezoelectric properties through an autoregressive sampling process. Starting from approximately 5000 generated structures, we implemented a comprehensive screening workflow incorporating structural validity, thermodynamic stability, and property verification. This approach identified several promising candidates from 4100 reconstructed structures, each representing compounds unrecorded in existing databases. Among these, the most notable material demonstrated a piezoelectric stress coefficient of 25.9 C/m(2) in the e[1,6] direction. Additionally, these materials demonstrate suitable bandgaps ranging from 1.63 to 3.61 eV, suggesting potential applications in high-sensitivity sensors and high-temperature electronics. Our work demonstrates the effectiveness of combining crystal structure language encoding with generative models for accelerating the discovery of functional materials with targeted properties.
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