在科学研究过程中,科研人员需要考虑针对不同的研究问题选择合适的研究方法,有时还会对研究方法进行优化,从而更好地解决研究问题。因此,研究方法往往是解决研究问题的关键,是学术文献的重要知识。帮助科研人员快速发现学术文献全文内...在科学研究过程中,科研人员需要考虑针对不同的研究问题选择合适的研究方法,有时还会对研究方法进行优化,从而更好地解决研究问题。因此,研究方法往往是解决研究问题的关键,是学术文献的重要知识。帮助科研人员快速发现学术文献全文内容中蕴含的方法实体,为其推荐适用于自身研究问题的关键解决方法提供实践参考,可以提高科研人员解决问题的效率。当前相关研究缺乏对方法实体之间共现关系的分析,未充分挖掘学术文献中蕴含的丰富知识。为此,本研究以自然语言处理领域为例,将方法实体细分为算法、数据集、指标以及工具4种类型,并标注了50篇论文作为训练语料。本研究构建了CRF(conditional random field)、BiLSTM(bi-directional long short-term memory)+CRF等4种实体抽取模型。研究结果表明,SciBERT(scientific bidirectional encoder representations from transformers)+CRF模型的性能最优。以ACL年会(Annual Meeting of the Association for Computational Linguistics)在2001—2020年共20年收录的论文全文数据为基础,进一步分析抽取出的方法实体的使用情况。本研究结合经典关联规则挖掘算法Apriori和卡方值构建方法实体共现数据集,并分析方法实体的演化。研究结果揭示了方法实体间的共现关系及其整体演化情况,可辅助特定领域的科研人员寻找合适的研究方法。展开更多
The hybrid genetic algorithm is utilized to facilitate model parameter estimation.The tri-dimensional compression tests of soil are performed to supply experimental data for identifying nonlinear constitutive model of...The hybrid genetic algorithm is utilized to facilitate model parameter estimation.The tri-dimensional compression tests of soil are performed to supply experimental data for identifying nonlinear constitutive model of soil.In order to save computing time during parameter inversion,a new procedure to compute the calculated strains is presented by multi-linear simplification approach instead of finite element method(FEM).The real-coded hybrid genetic algorithm is developed by combining normal genetic algorithm with gradient-based optimization algorithm.The numerical and experimental results for conditioned soil are compared.The forecast strains based on identified nonlinear constitutive model of soil agree well with observed ones.The effectiveness and accuracy of proposed parameter estimation approach are validated.展开更多
The influence of crystallographic orientation on the void growth in FCC crystals was numerically simulated with 3D crystal plasticity finite element by using a 3D unit cell including a spherical void, and the rate-dep...The influence of crystallographic orientation on the void growth in FCC crystals was numerically simulated with 3D crystal plasticity finite element by using a 3D unit cell including a spherical void, and the rate-dependent crystal plasticity theory was implemented as a user material subroutine. The results of the simulations show that crystallographic orientation has significant influence on the growth behavior of the void. Different active slip systems of the regions around the void cause the discontinuity in lattice rotation around the void, and the corner-like region is formed. In the case of the void located at grain boundary, large heterogeneous deformation occurs between the two grains, and the equivalent plastic deformation along grain boundary near the void in the case of θ=45^o （θ is the angle between grain boundary direction and X-axis） is larger than the others. Large difference of orientation factor of the two grains leads to large equivalent plastic deformation along grain boundary, and the unit cell is more likely to fail by intergranular fracture.展开更多
文摘在科学研究过程中,科研人员需要考虑针对不同的研究问题选择合适的研究方法,有时还会对研究方法进行优化,从而更好地解决研究问题。因此,研究方法往往是解决研究问题的关键,是学术文献的重要知识。帮助科研人员快速发现学术文献全文内容中蕴含的方法实体,为其推荐适用于自身研究问题的关键解决方法提供实践参考,可以提高科研人员解决问题的效率。当前相关研究缺乏对方法实体之间共现关系的分析,未充分挖掘学术文献中蕴含的丰富知识。为此,本研究以自然语言处理领域为例,将方法实体细分为算法、数据集、指标以及工具4种类型,并标注了50篇论文作为训练语料。本研究构建了CRF(conditional random field)、BiLSTM(bi-directional long short-term memory)+CRF等4种实体抽取模型。研究结果表明,SciBERT(scientific bidirectional encoder representations from transformers)+CRF模型的性能最优。以ACL年会(Annual Meeting of the Association for Computational Linguistics)在2001—2020年共20年收录的论文全文数据为基础,进一步分析抽取出的方法实体的使用情况。本研究结合经典关联规则挖掘算法Apriori和卡方值构建方法实体共现数据集,并分析方法实体的演化。研究结果揭示了方法实体间的共现关系及其整体演化情况,可辅助特定领域的科研人员寻找合适的研究方法。
基金Project(2007CB714006) supported by the National Basic Research Program of China Project(90815023) supported by the National Natural Science Foundation of China
文摘The hybrid genetic algorithm is utilized to facilitate model parameter estimation.The tri-dimensional compression tests of soil are performed to supply experimental data for identifying nonlinear constitutive model of soil.In order to save computing time during parameter inversion,a new procedure to compute the calculated strains is presented by multi-linear simplification approach instead of finite element method(FEM).The real-coded hybrid genetic algorithm is developed by combining normal genetic algorithm with gradient-based optimization algorithm.The numerical and experimental results for conditioned soil are compared.The forecast strains based on identified nonlinear constitutive model of soil agree well with observed ones.The effectiveness and accuracy of proposed parameter estimation approach are validated.
基金Project(2005CB623706) supported by the Major State Basic Research Development Program of China
文摘The influence of crystallographic orientation on the void growth in FCC crystals was numerically simulated with 3D crystal plasticity finite element by using a 3D unit cell including a spherical void, and the rate-dependent crystal plasticity theory was implemented as a user material subroutine. The results of the simulations show that crystallographic orientation has significant influence on the growth behavior of the void. Different active slip systems of the regions around the void cause the discontinuity in lattice rotation around the void, and the corner-like region is formed. In the case of the void located at grain boundary, large heterogeneous deformation occurs between the two grains, and the equivalent plastic deformation along grain boundary near the void in the case of θ=45^o （θ is the angle between grain boundary direction and X-axis） is larger than the others. Large difference of orientation factor of the two grains leads to large equivalent plastic deformation along grain boundary, and the unit cell is more likely to fail by intergranular fracture.
