475 research outputs found
Calibration on MEPDG Low Temperature Cracking Model and Recommendation on Asphalt Pavement Structures in Seasonal Frozen Region of China
In order to implement the Mechanistic-Empirical Pavement Design Guide (MEPDG) to design and maintain asphalt pavements in China, it is necessary to calibrate transfer functions of distresses in MEPDG with local conditions, including traffics, environment, and materials as well as measured pavement distresses data in field. Comprehensive single factor sensitivity analyses of factors that influence thermal cracking of asphalt pavements were conducted utilizing the MEPDG low temperature cracking (LTC) model. Additionally, multiple factor sensitivity analyses were carried out as well, based on which pavement structures with sound thermal cracking resistance were recommended for seasonal frozen regions in China. Finally, the field data of thermal cracks on typical asphalt pavements in China was utilized to calibrate the LTC model in MEPDG. An improvement was proposed on MEPDG LTC model, after which was applied, the predicted thermal cracking from MEPDG LTC model agrees well with measured thermal cracking in China
A Comparison of Hierarchical and Non-Hierarchical Bayesian Approaches for Fitting Allometric Larch (Larix.spp.) Biomass Equations
Accurate biomass estimations are important for assessing and monitoring forest carbon storage. Bayesian theory has been widely applied to tree biomass models. Recently, a hierarchical Bayesian approach has received increasing attention for improving biomass models. In this study, tree biomass data were obtained by sampling 310 trees from 209 permanent sample plots from larch plantations in six regions across China. Non-hierarchical and hierarchical Bayesian approaches were used to model allometric biomass equations. We found that the total, root, stem wood, stem bark, branch and foliage biomass model relationships were statistically significant (p-values \u3c 0.001) for both the non-hierarchical and hierarchical Bayesian approaches, but the hierarchical Bayesian approach increased the goodness-of-fit statistics over the non-hierarchical Bayesian approach. The R2 values of the hierarchical approach were higher than those of the non-hierarchical approach by 0.008, 0.018, 0.020, 0.003, 0.088 and 0.116 for the total tree, root, stem wood, stem bark, branch and foliage models, respectively. The hierarchical Bayesian approach significantly improved the accuracy of the biomass model (except for the stem bark) and can reflect regional differences by using random parameters to improve the regional scale model accuracy
DocGraphLM: Documental Graph Language Model for Information Extraction
Advances in Visually Rich Document Understanding (VrDU) have enabled
information extraction and question answering over documents with complex
layouts. Two tropes of architectures have emerged -- transformer-based models
inspired by LLMs, and Graph Neural Networks. In this paper, we introduce
DocGraphLM, a novel framework that combines pre-trained language models with
graph semantics. To achieve this, we propose 1) a joint encoder architecture to
represent documents, and 2) a novel link prediction approach to reconstruct
document graphs. DocGraphLM predicts both directions and distances between
nodes using a convergent joint loss function that prioritizes neighborhood
restoration and downweighs distant node detection. Our experiments on three
SotA datasets show consistent improvement on IE and QA tasks with the adoption
of graph features. Moreover, we report that adopting the graph features
accelerates convergence in the learning process during training, despite being
solely constructed through link prediction.Comment: Published at SIGIR'23 (repost for easier access
Recent Design Development in Molecular Imaging for Breast Cancer Detection Using Nanometer CMOS Based Sensors
As one of the key clinical imaging methods, the computed X-ray tomography can be further improved using new nanometer CMOS sensors. This will enhance the current technique's ability in terms of cancer detection size, position, and detection accuracy on the anatomical structures. The current paper reviewed designs of SOI-based CMOS sensors and their architectural design in mammography systems. Based on the existing experimental results, using the SOI technology can provide a low-noise (SNR around 87.8 db) and high-gain (30 v/v) CMOS imager. It is also expected that, together with the fast data acquisition designs, the new type of imagers may play important roles in the near-future high-dimensional images in additional to today's 2D imagers
A Wideband MIMO Channel Model for Aerial Intelligent Reflecting Surface-Assisted Wireless Communications
Compared to traditional intelligent reflecting surfaces(IRS), aerial IRS
(AIRS) has unique advantages, such as more flexible deployment and wider
service coverage. However, modeling AIRS in the channel presents new challenges
due to their mobility. In this paper, a three-dimensional (3D) wideband channel
model for AIRS and IRS joint-assisted multiple-input multiple-output (MIMO)
communication system is proposed, where considering the rotational degrees of
freedom in three directions and the motion angles of AIRS in space. Based on
the proposed model, the channel impulse response (CIR), correlation function,
and channel capacity are derived, and several feasible joint phase shifts
schemes for AIRS and IRS units are proposed. Simulation results show that the
proposed model can capture the channel characteristics accurately, and the
proposed phase shifts methods can effectively improve the channel statistical
characteristics and increase the system capacity. Additionally, we observe that
in certain scenarios, the paths involving the IRS and the line-of-sight (LoS)
paths exhibit similar characteristics. These findings provide valuable insights
for the future development of intelligent communication systems.Comment: 6 pages, 7 figure
Learning To Teach Large Language Models Logical Reasoning
Large language models (LLMs) have gained enormous attention from both
academia and industry, due to their exceptional ability in language generation
and extremely powerful generalization. However, current LLMs still output
unreliable content in practical reasoning tasks due to their inherent issues
(e.g., hallucination). To better disentangle this problem, in this paper, we
conduct an in-depth investigation to systematically explore the capability of
LLMs in logical reasoning. More in detail, we first investigate the deficiency
of LLMs in logical reasoning on different tasks, including event relation
extraction and deductive reasoning. Our study demonstrates that LLMs are not
good reasoners in solving tasks with rigorous reasoning and will produce
counterfactual answers, which require us to iteratively refine. Therefore, we
comprehensively explore different strategies to endow LLMs with logical
reasoning ability, and thus enable them to generate more logically consistent
answers across different scenarios. Based on our approach, we also contribute a
synthesized dataset (LLM-LR) involving multi-hop reasoning for evaluation and
pre-training. Extensive quantitative and qualitative analyses on different
tasks also validate the effectiveness and necessity of teaching LLMs with logic
and provide insights for solving practical tasks with LLMs in future work
Dynamic modeling and optimization of an eight bar stamping mechanism based on RBF neural network PID control
Introduction: Modern industrial manufacturing often requires the eight-bar stamping mechanism to have high motion accuracy and stability. To meet these stringent requirements, traditional control techniques such as proportional-integral-derivative (PID) control need to be improved.Methods: In this study, radial basis function neural network is introduced to improve the traditional proportional integral derivative control technique. The improved proportional integral derivative technique is applied to the modeling and optimization of eight kinds of bar stamping mechanisms.Results: Comparing the improved control technology, the experiment showed that the peak time and adjustment time of the improved technology were 0.516 s and 1.038 s, respectively, which are better than the comparative control technology. In addition, in the comparative analysis of the eight bar stamping mechanism, the proposed architecture scored 9.3 points in operational efficiency, which is significantly greater than the comparative architecture.Discussion: The results show that the combination of PID control strategy and radial basis function neural network provides a powerful tool for dynamic modeling and optimization of eight-bar stamping mechanism. It not only provides enhanced motion accuracy and stability, but also brings significant practicality to industrial manufacturing. This integration opens up new possibilities for improving the performance of complex mechanical systems to meet the evolving needs of modern manufacturing
- …