5,364 research outputs found
Void Generation Between Shell and Charge ofWarhead under the Projection Load
In the process of projecting, the coupled property of warhead shell and charge is an important issueof the launching safety study. To maintain charge in close contact with the shell is one of the requirementsfor quality. For solid-liquid mixed charge , its tensile strength is very small, the dynamic response characteristicbetween warhead shell and charge make it possible to form instantaneous void between the shell and charge.his paper studies the impact of factors of instantaneous void and its development law by numerical simulation.This work lays foundation for warhead charge quality control and projection safety.Defence Science Journal, 2008, 58(6), pp.715-720, DOI:http://dx.doi.org/10.14429/dsj.58.169
Gaussian-Gamma collaborative filtering: a hierarchical Bayesian model for recommender systems
The traditional collaborative filtering (CF) suffers from two key challenges, namely, the normal assumption that it is not robust, and it is difficult to set in advance the penalty terms of the latent features. We therefore propose a hierarchical Bayesian model-based CF and the related inference algorithm. Specifically, we impose a Gaussian-Gamma prior on the ratings, and the latent features. We show the model is more robust, and the penalty terms can be adapted automatically in the inference. We use Gibbs sampler for the inference and provide a statistical explanation. We verify the performance using both synthetic and real dataset
Sparse Attention-Based Neural Networks for Code Classification
Categorizing source codes accurately and efficiently is a challenging problem
in real-world programming education platform management. In recent years,
model-based approaches utilizing abstract syntax trees (ASTs) have been widely
applied to code classification tasks. We introduce an approach named the Sparse
Attention-based neural network for Code Classification (SACC) in this paper.
The approach involves two main steps: In the first step, source code undergoes
syntax parsing and preprocessing. The generated abstract syntax tree is split
into sequences of subtrees and then encoded using a recursive neural network to
obtain a high-dimensional representation. This step simultaneously considers
both the logical structure and lexical level information contained within the
code. In the second step, the encoded sequences of subtrees are fed into a
Transformer model that incorporates sparse attention mechanisms for the purpose
of classification. This method efficiently reduces the computational cost of
the self-attention mechanisms, thus improving the training speed while
preserving effectiveness. Our work introduces a carefully designed sparse
attention pattern that is specifically designed to meet the unique needs of
code classification tasks. This design helps reduce the influence of redundant
information and enhances the overall performance of the model. Finally, we also
deal with problems in previous related research, which include issues like
incomplete classification labels and a small dataset size. We annotated the
CodeNet dataset with algorithm-related labeling categories, which contains a
significantly large amount of data. Extensive comparative experimental results
demonstrate the effectiveness and efficiency of SACC for the code
classification tasks.Comment: 2023 3rd International Conference on Digital Society and Intelligent
Systems (DSInS 2023
Case Study – Ground Failures and Ruptures in Xian City
Xian city, the most well known ancient city of China for her incredible Terra Cotta Warriers and so forth, has been suffered from ground fracture for years. Surface ruptures and faultings encountered in strips all over the city. Hundreds of buildings were severely destroyed and many of them even have been demolished. Ground failures wide-spread and enlarged from time to time, especially right from Tangshan earthquake of July 28, 1976. Therefore serious concerns and suspicious of being associated with major earthquakes have arosed. Thus it has been a problem of both engineering and social influence. Like many other cities in China and even in the world such as Houston, Texas, USA, surface faulting or surface rupture often caused many guess-works and arguments among different engineers, geologists and seismologists. In turn, many projects either underway or co be undertaken will be seriously lagged out due to discrepancies of different assessment and measures of mitigation. The authors have been deeply involved in surface faulting and ruptures as a background for exploring the mechanism and predicting its possible effects from the engineering point of view. In this paper, the authors introduce their systematic ease study on Xian ground failures towards this end, including site investigations, typical damages assessment, numerical analysis on fracture mechanism, model tests in laboratory and comprehensive evaluations etc. Conclusions were drawn not only for this particular ancient city but also provided a referential real ease for the like in the world
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