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。     

基于测试性设计特性的样本量确定方法

针对测试性验证试验方法的局限性,提出了一种新的故障样本量的确定方法。根据系统的测试性特性,建立单元、功能、性能和测试之间的相关矩阵;选择相关矩阵的列权值最大的列删减单元功能相关矩阵和功能性能相关矩阵,依次遍历完所有列,获取样本和样本数量;利用实例进行了验证,结果表明：计算过程简单,结果更符合实际系统测试性验证试验对于样本量的要求。     

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.     

基于桥连接的词典学习方法的语义解析

现阶段的语义解析方法大部分都基于组合语义,这类方法的核心就是词典。词典是词汇的集合,词汇定义了自然语言句子中词语到知识库本体中谓词的映射。语义解析一直面临着词典中词汇覆盖度不够的问题。针对此问题,该文在现有工作的基础上,提出了基于桥连接的词典学习方法,该方法能够在训练中自动引入新的词汇并加以学习,为了进一步提高新学习到的词汇的准确度,该文设计了新的词语—二元谓词的特征模板,并使用基于投票机制的核心词典获取方法。该文在两个公开数据集(WebQuestions和Free917)上进行了对比实验,实验结果表明,该文方法能够学习到新的词汇,提高词汇的覆盖度,进而提升语义解析系统的性能,特别是召回率。     

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.     

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.     

DiSeg 1.0: The first system for Spanish discourse segmentation

Nowadays discourse parsing is a very prominent research topic. However, there is not a discourse parser for Spanish texts. The first stage in order to develop this tool is discourse segmentation. In this work, we present DiSeg, the first discourse segmenter for Spanish, which uses the framework of Rhetorical Structure Theory and is based on lexical and syntactic rules. We describe the system and we evaluate its performance against a gold standard corpus, divided in a medical and a terminological subcorpus. We obtain promising results, which means that discourse segmentation is possible using shallow parsing.     

TSPN: Term-Based Semantic Peer-to-Peer Networks

In this paper,we propose Term-based Semantic Peerto-Peer Networks (TSPN) to achieve semantic search.For each peer,TSPN builds a full text index of its documents.Through the analysis of resources,TSPN o...     

开挖扰动区内岩石的压密特性和强度恢复性研究

 利用交替变换荷载速率试验研究压密后岩石试样的强度恢复和荷载速率依存性。首先,分别对田下凝灰岩、来待砂岩、河津凝灰岩和三城目安山岩4种岩石试样在空心圆筒内进行压缩破坏,然后持续轴向加载,压密破坏后的岩石试样。从空心圆筒中推出压密后的试样,进行单轴压缩下的交替变换荷载速率试验,即按一定应变或位移间隔,对同一试样交替施加高低2种不同的荷载速率,得到对应于2种荷载速率的应力–应变曲线。在整个交替变换荷载速率试验过程中,应力随荷载速率的切换而增减。从交替变换荷载速率试验得到的应力–应变曲线上的荷载速率切换点出发,利用3次样条曲线拟合得到2条对应于高低2种荷载速率的应力–应变曲线,并求解强度点处荷载速率依存性参数n。试验结果表明,田下凝灰岩、来待砂岩和河津凝灰岩的强度恢复现象明显,单轴抗压强度随着压密试验中轴向最大荷载的增加而增加,但没有观察到三城目安山岩的强度恢复现象。当压密试验中的最大轴向荷载较大时,压密后的试样的荷载速率依存性与完整试样的基本一致。当压密试验中的最大轴向荷载较小时,从极大和极小2个方面求解荷载速率依存性参数n,得出完整试样的n值介于压密试样的极大值 和极小值 之间,且差值不大。研究结果表明,在进行适当支护之后,随着时间的推移,开挖扰动区内的岩石存在强度恢复的可能性,且今后利用数值模拟考虑开挖扰动区内的岩石强度恢复特性和时间依存性时,在本构方程中可以采用与完整围岩区域一样的参数,从而简化数值模拟程序。