结合句法依存信息的方面级情感分类

引入句法依存信息到原方面术语,提出一种新的方面术语表示方法,利用Glove词向量表示单词以及单词与单词之间的依存关系,构造出包含句法依存信息的依存关系邻接矩阵和依存关系表示矩阵,利用图卷积神经网络和多头注意力机制将句法依存信息融入到方面术语中,使得方面术语表达与上下文结构高度相关。将改进后的方面词术语表示替换到现有模型后,模型泛化能力得到有效提升。对比试验和分析结果表明:该方法具有有效性和泛化性。     

Thickness dependent barrier performance of permeation barriers made from atomic layer deposited alumina for organic devices

Organic devices like organic light emitting diodes (OLEDs) or organic solar cells degrade fast when exposed to ambient air. Hence, thin-films acting as permeation barriers are needed for their protection. Atomic layer deposition (ALD) is known to be one of the best technologies to reach barriers with a low defect density at gentle process conditions. As well, ALD is reported to be one of the thinnest barrier layers, with a critical thickness – defining a continuous barrier film – as low as 5–10 nm for ALD processed Al₂O₃. In this work, we investigate the barrier performance of Al₂O₃ films processed by ALD at 80 °C with trimethylaluminum and ozone as precursors. The coverage of defects in such films is investigated on a 5 nm thick Al₂O₃ film, i.e. below the critical thickness, on calcium using atomic force microscopy (AFM). We find for this sub-critical thickness regime that all spots giving raise to water ingress on the 20 × 20 μm² scan range are positioned on nearly flat surface sites without the presence of particles or large substrate features. Hence below the critical thickness, ALD leaves open or at least weakly covered spots even on feature-free surface sites. The thickness dependent performance of these barrier films is investigated for thicknesses ranging from 15 to 100 nm, i.e. above the assumed critical film thickness of this system. To measure the barrier performance, electrical calcium corrosion tests are used in order to measure the water vapor transmission rate (WVTR), electrodeposition is used in order to decorate and count defects, and dark spot growth on OLEDs is used in order to confirm the results for real devices. For 15–25 nm barrier thickness, we observe an exponential decrease in defect density with barrier thickness which explains the likewise observed exponential decrease in WVTR and OLED degradation rate. Above 25 nm, a further increase in barrier thickness leads to a further exponential decrease in defect density, but an only sub-exponential decrease in WVTR and OLED degradation rate. In conclusion, the performance of the thin Al₂O₃ permeation barrier is dominated by its defect density. This defect density is reduced exponentially with increasing barrier thickness for alumina thicknesses of up to at least 25 nm.     

关于三峡库区周边坡体岩石特性的考察

岩石强度的载荷速率相关性与岩石的时间相关性特性及粘弹性性质密切相关，而且强度的栽荷速率相关性越大，越容易发生蠕变破坏。对于坡体来说，如果构成坡体的岩石的时间相关性很显著．那么即使在比较低的应力下仅施加一点载荷，也容易发生变形。针对三峡库区周边滑坡多发，采集了组成滑坡坡体的4类主要岩石-泥岩、灰岩、泥质砂岩及砂岩。通过室内岩石力学强度试验，获得了不同岩石的强度特性曲线及表示载荷速率相关性的参数n。利用一个试件通过载荷速率交替变换获得了不同应变速率下的应力-应变曲线，从而根据强度的变化率不仅获得了峰值强度的载荷速率相关性，而且还求得了残余强度的载荷速率相关性。在单轴压缩试验中，残余强度的n值与峰值强度的n值有较大的差异，但在三轴压缩试验中两者的差异却不太明显。而且在气干状态下，不管是峰值强度还是残余强度的n值均随着围压的增加而增加。     

Path-dependency in public–private partnership in French urban renewal

Public–private partnership in urban renewal in France concerns mainly housing, transport infrastructure and large public facilities. The distinction between public, private and civil actors does not concern social and economic development. This situation tends to limit the integration of different issues and approaches in renewal projects. Also, French urban renewal projects do not produce a new type of partnership between public and private actors and the regulatory framework. These projects remain publicly dominated policy-making procedures because of the uneven distribution of resources and assets and despite a policy discourse emphasising the need for a new division of work between state, market and civil society. The current French situation cannot be understood without bearing in mind the history of urban planning policies in France. Using a historical analysis and the path-dependence approach, we highlight the resilience of inherited structures of interaction between public and private actors.     

砖砌体结构在小震下的失效相关性分析

本文运用可靠度理论,依据我国现行的砌体结构设计规范,建立起抗震和非抗震的砖砌体墙的试验模型。采用Monte-Carlo随机模拟法,在水平地震作用下对两类(抗震和非抗震)砖墙模型进行了分析。根据统计学原理,总结出小震下砖砌体墙的失效规律和失效相关性规律。以期为砌体结构的可靠性分析、抗震加固及震后维修等理论提供具有参考意义的分析依据。     

基于多特征量的D矩阵模型的建立与分析

针对基于单特征量的D矩阵模型会损失测试信号的大量信息的问题,提出了一种基于多特征量的可测性分析模型。首先,在研究D矩阵模型的基础上,对测试信号进行特征提取和多值编码,建立了基于多特征量的D矩阵模型。其次,基于信息熵制定诊断策略和生成故障诊断树,并对模型进行测试性分析,评估其诊断能力。结果表明,与单特征量的D矩阵模型相比,基于多特征量的D矩阵模型选用的测试点数和模糊组数小,故障隔离率高,诊断测试步骤数少,平均测试费用低。     

Combined continuum damage‐embedded discontinuity model for explicit dynamic fracture analyses of quasi‐brittle materials

In this paper, a novel constitutive model combining continuum damage with embedded discontinuity is developed for explicit dynamic analyses of quasi‐brittle failure phenomena. The model is capable of describing the rate‐dependent behavior in dynamics and the three phases in failure of quasi‐brittle materials. The first phase is always linear elastic, followed by the second phase corresponding to fracture‐process zone creation, represented with rate‐dependent continuum damage with isotropic hardening formulated by utilizing consistency approach. The third and final phase, involving nonlinear softening, is formulated by using an embedded displacement discontinuity model with constant displacement jumps both in normal and tangential directions. The proposed model is capable of describing the rate‐dependent ductile to brittle transition typical of cohesive materials (e.g., rocks and ice). The model is implemented in the finite element setting by using the CST elements. The displacement jump vector is solved for implicitly at the local (finite element) level along with a viscoplastic return mapping algorithm, whereas the global equations of motion are solved with explicit time‐stepping scheme. The model performance is illustrated by several numerical simulations, including both material point and structural tests. The final validation example concerns the dynamic Brazilian disc test on rock material under plane stress assumption. Copyright © 2014 John Wiley & Sons, Ltd.     

Optimal capacity design of battery and hydrogen system for the DC grid with photovoltaic power generation based on the rapid estimation of grid dependency

This paper presents a fast and novel method to determine the optimal capacity of a battery and a hydrogen system for a grid-connected photovoltaic (PV) system based on the required grid dependency (GD) and the minimum Levelized Cost of Energy (LCE). The GD is calculated from the weather data at 9 locations throughout Japan during 25 years considering different sizing of PV, battery, and hydrogen system. Based on the results, the relationship between the GD and the capacities of the devices and the weather parameter is established. The results show that the GD depends on the annual total solar insolation and the devices’ capacities as well. The empirical GD formula is then examined at a different location in Japan. The proposed GD calculation agrees well with the GD obtained from the real 25 – year weather data and shows great advantages over the conventional method in the simplicity and calculation time. In addition, the optimal capacity of the system can be obtained directly from the GD formula and the objective function of the LCE.     

I/O-efficient join dependency testing,Loomis–Whitney join,and triangle enumeration

We revisit two fundamental problems in database theory. The join-dependency (JD) testing problem is to determine whether a given JD holds on a relation r. We prove that the problem is NP-hard even if the JD involves only relations each of which has only two attributes. The JD-existence testing problem is to determine if there exists any non-trivial JD satisfied by r. We present an I/O-efficient algorithm in the external memory model, which in fact settles the closely related Loomis–Whitney enumeration problem. As a side product, we solve the triangle enumeration problem with the optimal I/O-complexity, improving a recent result of Pagh and Silvestri in PODS'14.     

Simulation of rate dependent fracture in concrete using an irregular lattice model

An irregular lattice model is used to simulate concrete fracture behavior under dynamic loadings. The numerical approach is based on rigid-body-spring networks, in which a visco-plastic damage model is applied to describe the rate dependency. A direct tensile test is simulated at various strain rates, and the dynamic strength increase is obtained in terms of dynamic increase factor (DIF). The DIFs are compared with a previous experimental and empirical study to calibrate the visco-plastic parameters. Next, a three-point-bending test is conducted numerically under impact and slow loadings, where the mixed-mode fracture is set up with a notch offset from the midspan. The rate-sensitive failure features are shown at the two different loading rates, and the rate effect on the failure mechanism is related with the peak load in the loading history. This study provides qualitative and quantitative understandings of the rate dependent failure behaviors in concrete.