面向属性抽取的门控动态注意力机制

在现阶段属性抽取研究中,现有注意力建模及训练较刚性(单句一次成型),而单句中不同词汇的上下文存在语境语义的差异,一致的注意力分布缺少动态的适应性.因此,文中提出面向属性抽取的门控动态注意力机制,利用双向长短时记忆网络捕获目标句中每个单词的隐层表示.在注意力模型处理词一级属性预测时,根据目标词及其上下文,计算适应该目标词的注意力分布向量,可以根据上下文的变化自动调整注意力权重的分配.借助门控调整注意力向量流向下一层神经元的信息量,最终使用条件随机场进行属性标记.应用2014-2016语义评估官方数据集验证文中方法的有效性,F1值均有所提高.     

Buckling of an Adhesive Polymeric Micropillar

Adhesion and buckling of single PDMS micropillars were investigated as a function of compressive preload. The micropillars had diameters of 10, 12, 14, and 20 μm and aspect ratios of 1 to 3.3. Adhesion generally increased with a decrease in the aspect ratio. A dependence of pull-off strength on the compressive preload stress was found for micropillars that underwent buckling. When buckling was reversible, tip contact recovered upon unbuckling, which resulted in only a slight reduction of adhesion. In situ observation studies identified irreversible buckling, i.e., lack of tip-contact re-formation, resulting in adhesion loss. It is concluded that the edge radius of the tip, which acts as a circumferential crack, controls adhesion. Fibril buckling is found to be broadly consistent with the predictions of Euler buckling theory.     

任意倾斜角度下平行平板封闭夹层自然对流换热实验研究

通过实验，在温差从10℃到90℃，夹层间距从0．01m至0．08m，空气层与水平面夹角在0°～90°变化范围内，全面分析了夹层温差、夹角、Re数、间距、纵深比等因素对换热的影响．拟合出了各角度下的准则方程式，并在θ＞60°时，用（1－θ／18O）n来体现角度变化对换热的影响，避免出现90°时准则式与其它角度下形式无法统一的问题．分析了一定温差、角度下对流换热量随间距的变化关系，给出了最佳间距，从而为工程计算提供了理论依据．     

Influence of the pH on the ZnO nanoparticle growth in supercritical water: Experimental and simulation approaches

In order to improve the knowledge on the nucleation and the growth mechanisms of metal oxides nanoparticles produced in supercritical water domain, ZnO was used as a “model” material. A continuous process of hydrothermal synthesis was employed to synthesize ZnO nanopowders (T = 410 °C and P = 305 bar) from Zn(NO₃)₂ and KOH solutions with different values of [KOH]/[Zn(II)] ratio from 0 to 8 in order to investigate the pH effect on the growth of ZnO nanocrystallite in terms of size and morphology. The samples were characterized by X-Ray Diffraction and Transmission Electronic Microscopy. ZnO crystal was considered as a cylindrical crystallite with a diameter D and height H. Especially, the aspect ratio D/H was already used to observe the change of ZnO nanoparticle shape correlated with TEM observations and results from a CFD simulation model. A schematic synoptic of the ZnO growth in supercritical domain is also presented.     

Synthesis of rod-like β-Si3N4 seed crystals with tailored morphology

β-Si₃N₄ seed crystals were synthesized by sintering (α+β)-Si₃N₄ powders with Y₂O₃+MgO additives at 1800 °C. Full α- to β-phase transformation was achievable at 1800 °C for 1 h. The pre-existing β-Si₃N₄ particles acted as nuclei during a sintering process. The length and mean aspect ratio of β-Si₃N₄ seed grains could be tailored by careful control of α/β-Si₃N₄ ratio, which resulted in various nuclei and driving force. The sample A95B5 with 5% β-nuclei shows a bimodal size distribution containing large amount of abnormal elongated β-Si₃N₄ grains with remarkable large diameter. With increasing the β-phase content from 5 wt% to 100 wt%, the average diameter and aspect ratio of the β-Si₃N₄ single crystals decreased from 1.43 µm to 0.92 µm and from 4.36 to 2.79, respectively.     

Rapid and low temperature spark plasma sintering synthesis of novel carbon nanotube reinforced titanium matrix composites

Multi–walled carbon nanotube (MWCNT) reinforced titanium matrix composites were synthesized using a spark plasma sintering method at a low sintering temperature of 550 °C. The effects of the weight fraction of MWCNTs on the microstructures and the mechanical and thermal properties of the composites were investigated. No reaction products were detected in the composites, indicating that the MWCNTs in the composites maintained their structural integrity after sintering, and thus, because of their advantageous properties, could reinforce the titanium matrix. As a result, the compressive strength of the composite containing 0.4 wt.% MWCNTs reached 1106 MPa, which was an increase of 61.5% compared to that of pure titanium under at the same conditions. In addition, the results revealed that compressive strength of the bulk compacts increased initially and then decreased with an increase in weight fraction of MWCNTs. However, compressive strain of the sintered composites continued to fall at a slow rate. The microhardness and thermal diffusivity of the composites rose steadily with an increasing content of MWCNTs. When the weight fraction of MWCNTs in the composites exceeded 0.8%, the compressive strength of the composites declined significantly due to the increasing aggregation of the MWCNTs.     

An Aspect-Oriented Approach to Modular Behavioral Specification

Behavioral interface specification languages, such as Java Modeling Language (JML), can be used to specify the behavior of program modules. We have developed a behavioral interface specification language Moxa, an extension of JML. Moxa provides a new modularization mechanism called assertion aspect that can capture the crosscutting properties among assertions. In this paper, we briefly explain the notion of assertion aspects and the design of Moxa, and then we show an example specification. By comparing the specification to its JML counterpart, we show that the use of assertion aspects clarifies the large, complex specification and greatly simplifies each assertion in the specification.     

Merging enriched Finite Element triangle meshes for fast prototyping of alternate solutions in the context of industrial maintenance

A new approach to the merging of Finite Element (FE) triangle meshes is proposed. Not only it takes into account the geometric aspects, but it also considers the way the semantic information possibly associated to the groups of entities (nodes, faces) can be maintained. Such high level modification capabilities are of major importance in all the engineering activities requiring fast modifications of meshes without going back to the CAD model. This is especially true in the context of industrial maintenance where the engineers often have to solve critical problems in very short time. Indeed, in this case, the product is already designed, the CAD models are not necessarily available and the FE models might be tuned. Thus, the product behaviour has to be studied and improved during its exploitation while prototyping directly several alternate solutions. Such a framework also finds interest in the preliminary design phases where alternative solutions have to be simulated. The algorithm first removes the intersecting faces in an n-ring neighbourhood so that the filling of the created holes produces triangles whose sizes smoothly evolve according to the possibly heterogeneous sizes of the surrounding triangles. The hole-filling algorithm is driven by an aspect ratio factor which ensures that the produced triangulation fits well the FE requirements. It is also constrained by the boundaries of the groups of entities gathering together the simulation semantic. The filled areas are then deformed to blend smoothly with the surroundings meshes.     

Mining early aspects based on syntactical and dependency analyses

Aspect-Oriented Requirements Engineering focuses on the identification and modularisation of crosscutting concerns at early stages. There are different approaches in the requirements engineering community to deal with crosscutting concerns, introducing the benefits of the application of aspect-oriented approaches at these early stages of development. However, most of these approaches rely on the use of Natural Language Processing techniques for aspect identification in textual documents and thus, they lack a unified process that generalises its application to other requirements artefacts such as use case diagrams or viewpoints. In this paper, we propose a process for mining early aspects, i.e. identifying crosscutting concerns at the requirements level. This process is based on a crosscutting pattern where two different domains are related. These two different domains may represent different artefacts of the requirements analysis such as text and use cases or concerns and use cases. The process uses syntactical and dependency based analyses to automatically identify crosscutting concerns at the requirements level. Validation of the process is illustrated by applying it to several systems and showing a comparison with other early aspects tools. A set of aspect-oriented metrics is also used to show this validation.     

方面化构件组装体系结构描述语言AWright

方面化构件组装平台迫切需要一种新的软件体系结构描述语言来支持该平台的体系结构描述及验证。针对该平台特点,在分析Wright的基础上,提出一种扩展Wright的方面化构件组装体系结构描述语言——AWright。给出该体系结构描述语言的医疗诊断系统实例,以说明AWright的机制及其描述能力。