47 research outputs found
The History, Present and Future of the Study of Chinese Logic
The study of Chinese logic started as the second wave of Western traditional logic spread through China. Following Sun Yirang’s initial work and Liu Shipei’s development of it, this field was preliminarily established by Hu Shi, Zhang Shizhao and Guo Zhanbo. Since the 1980s, it became commonplace to systematize Chinese logic based on the Western system of logic. Since the 1990s, though, the Chinese academic community has begun to reflect on this research method, which has led to the trend of reverting to Chinese culture and its own logic
Rethinking the Open-Loop Evaluation of End-to-End Autonomous Driving in nuScenes
Modern autonomous driving systems are typically divided into three main
tasks: perception, prediction, and planning. The planning task involves
predicting the trajectory of the ego vehicle based on inputs from both internal
intention and the external environment, and manipulating the vehicle
accordingly. Most existing works evaluate their performance on the nuScenes
dataset using the L2 error and collision rate between the predicted
trajectories and the ground truth. In this paper, we reevaluate these existing
evaluation metrics and explore whether they accurately measure the superiority
of different methods. Specifically, we design an MLP-based method that takes
raw sensor data (e.g., past trajectory, velocity, etc.) as input and directly
outputs the future trajectory of the ego vehicle, without using any perception
or prediction information such as camera images or LiDAR. Our simple method
achieves similar end-to-end planning performance on the nuScenes dataset with
other perception-based methods, reducing the average L2 error by about 20%.
Meanwhile, the perception-based methods have an advantage in terms of collision
rate. We further conduct in-depth analysis and provide new insights into the
factors that are critical for the success of the planning task on nuScenes
dataset. Our observation also indicates that we need to rethink the current
open-loop evaluation scheme of end-to-end autonomous driving in nuScenes. Codes
are available at https://github.com/E2E-AD/AD-MLP.Comment: Technical report. Code is availabl
Solvent fuming dual-responsive switching of both wettability and solid-state luminescence in silole film
A multiresponsive switcher on both wettability and solid-state luminescence has great application potentials in novel smart devices. In this paper, a silole molecule of 1,2,3,4,5-hexaphenylsilole (HPS) was chosen to prepare thin films by spin-coating, and a solvent fuming dual-responsive switcher combining photoluminescent behavior and wettability was successfully achieved by changing the mode of solid-state molecular packing. This study suggests that HPS and other silole derivatives have a promising future for use in dual- and multifunctional switches in new technological applications
Effect of final cooling temperature on the microstructure and mechanical properties of high-strength anti-seismic rebar
Rebar is an important material in the major structural engineering, and its fine structure has a very important effect on the performance of the rebar. In this work, the Gleeble-3800 thermal simulator was used to simulate and control the final cooling temperature process to explore the effect of the precipitation behavior of the microalloying elements on the microstructure and mechanical properties of the rebar. The electron backscatter diffraction (EBSD), high-resolution transmission electron microscope (TEM), and universal tensile testing machine were used to characterize the microstructural transformation and mechanical properties of high-strength anti-seismic rebar. The results shows that under the conditions of different final cooling temperatures, the microstructure of the rebar were mainly composed of ferrite and pearlite. When the final cooling temperature decreased from 750 °C to 650 °C, the ferrite grain size decreased from 0.01237 mm to 0.00678 mm and the pearlite lamellar spacing decreased from 0.226 μ m to 0.114 μ m. The EBSD results found that the most of ferrite grains with larger misorientation angle (20° ∼ 60°) formed by the different austenite grains. The TEM results found that the main precipitates were (Nb, Ti, V) C, which precipitated on the ferrite matrix, and the shapes were oval, and the average particle sizes were about 20 ∼ 30 nm. When the final cooling temperature was 650 °C, the tensile strength and yield strength of the rebar reached 712.94 MPa and 562.97 MPa, respectively, and strength yield ratio was 1.27. With the decreases in the final cooling temperature, the tensile strength and yield strength of the rebar gradually increased
Stereoscopic Monitoring Methods for Flood Disasters Based on ICESat-2 and Sentinel-2 Data
Climate change has led to an increased frequency of extreme precipitation events, resulting in increased damage from rainstorms and floods. Rapid and efficient flood forecasting is crucial. However, traditional hydrological simulation methods that rely on site distribution are limited by the limited availability of data and cannot provide fast and accurate flood monitoring information. Therefore, this study took the flood event in Huoqiu County in 2020 as an example and proposes a three-dimensional flood monitoring method based on active and passive satellites, which provides effective information support for disaster prevention and mitigation. The experimental results indicated the following: (1) the flood-inundated area was 704.1 km2, with the Jiangtang Lake section of the Huaihe River and the southern part of Chengdong Lake being the largest affected areas; (2) water levels in the study area ranged from 15.36 m to 17.11 m, which is 4–6 m higher than the original water level. The highest flood water level areas were the Jiangtang Lake section and the flat area in the south of Chengdong Lake, with Chengdong Lake and the north of Chengxi Lake having the greatest water level increase; (3) the flood water depth was primarily between 4 m and 7 m, with a total flood storage capacity of 2833.47 million m3, with Jiangtang Lake having the largest flood storage capacity; and (4) the rainstorm and flood disaster caused a direct economic loss of approximately CNY 7.5 billion and affected a population of approximately 91 thousand people. Three-dimensional monitoring of floods comprehensively reflects the inundation status of floods and can provide valuable information for flood prediction and management
Nonlinear dynamic separation characteristics of friction pair and experimental analysis
Abstract This paper aims to reduce friction pair erosion of the clutch in the case of continuous shift; the dynamic separation process of the friction pair is investigated. The temperature of the friction pair, friction torque, and separation speed in the separation process are taken as the research objects, and the dynamics simulation model and finite element thermal coupling simulation model of the clutch separation process are established. The nonlinear dynamic separation characteristics of the friction pair are investigated by comparing and analyzing the effects of control parameters such as rotational speed difference, damping ratio, and lubricant viscosity on the friction torque, friction pair separation speed, separation gap, and contact stress during the separation process. The gap recovery coefficient is proposed as a response indicator for observing the separation process in response to the inability to observe the nonlinear dynamic motion of the friction pair during the separation process and to measure the end time of the separation. Finally, the clutch was subjected to a separation test. The results show that the proposed gap recovery coefficient accurately describes the separation process. The simulation model can simulate the clutch's separation and predict the trend of separation parameters
Predicting Flood Event Class Using a Novel Class Membership Function and Hydrological Modeling
Abstract Predicting flood event classes aids in the comprehensive investigation of flood behavior dynamics and supports flood early warning and emergency plan development. Existing studies have mainly focused on historical flood event classification and the prediction of flood hydrographs or certain metrics (e.g., magnitude and timing) but have not focused on predicting flood event classes. Our study proposes a new approach for predicting flood event classes based on the class membership functions of flood regime metrics and hydrological modeling. The approach is validated using 1446 unimpacted flood events in 68 headstream catchments widely distributed across China. The new approach performs well, with class hit rates of 68.3% ± 0.4% for all events; 65.8% ± 0.6%, 56.8% ± 0.9%, and 69.5% ± 0.9% for the small, moderate and high spike flood event classes, respectively; and 82.5% ± 1.2% and 75.4% ± 1.1% for the moderate and high dumpy flood event classes, respectively. Furthermore, it performs better in the basins of northern China than in those of southern China, particularly for the small spike flood event class in the Songliao and Yellow River Basins, with hit rates of 80.0% ± 3.2% and 78.8% ± 3.2%, respectively. Our results indicate that the new approach will help improve the prediction performance of flood events and their corresponding classes, and provide deep insights into the comprehensive dynamic patterns of flood events for early warning and control management
Fabrication of hexaphenylsilole nanowires and their morphology-tunable photoluminescence
Immersion of nanoporous alumina membranes into saturated solutions of hexaphenylsilole with subsequent solvent evoporation affords aligned organic nanowires. The luminescent properties of the hexaphenylsilole nonowires can be manipulated by varying their morphologies, which were controlled by changing the channel sizes of the alumina templates