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61.
Aspect-based sentiment analysis systems are a kind of text-mining systems that specialize in summarizing the sentiment that a collection of reviews convey regarding some aspects of an item. There are many cases in which users write their reviews using conditional sentences; in such cases, mining the conditions so that they can be analyzed is very important not to misinterpret the corresponding sentiment summaries. Unfortunately, current commercial systems or research systems neglect conditions; current frameworks and toolkits do not provide any components to mine them; furthermore, the proposals in the literature are insufficient because they are based on handcrafted patterns that fall short regarding recall or machine learning procedures that are tightly bound with a specific language and require too much configuration. In this article, we present Torii, which is a system that loads a collection of reviews, discovers the aspects on which they report, and summarizes the sentiment that is conveyed on them taking into account the existing conditions, if any. We also describe its architecture, our approach to mine conditions, and our experimental analysis on a large multilingual data set with reviews from multiple categories. To the best of our knowledge, Torii is the first proposal that addresses aspect-based sentiment analysis taking conditions into account. 相似文献
62.
擦拭样品微粒分析技术是核保障环境样品分析的一种主要手段,从大量灰尘颗粒中识别并定位含高浓铀(HEU)或含Pu微粒是微粒分析首先需要解决的问题。本文以HEU和Pu微粒为研究对象,建立了用于微粒α径迹测量的样品制备方法,采用CR-39固体径迹探测器为α径迹探测器,测量了不同蚀刻时间2种微粒产生的α径迹星的径迹参数。结果表明:可通过测量径迹短轴与曲率直径并作图来分辨HEU和Pu微粒,该方法对于蚀刻时间大于10 h的微粒径迹星,均能明显分辨,对于径迹非常密集的径迹星,也能准确分辨。 相似文献
63.
为研究磁流变阻尼器(MRD)在拟静态作用下的力学性能,制作了一个四线圈剪切阀式MRD,在不同电流和不同位移幅值下采用三角位移加载制度对MRD进行了拟静态试验,研究了MRD的力学性能随电流和位移幅值的变化规律,分析了阻尼力波动现象产生的原因;根据试验结果提出了一种拟静态作用下修正的力学模型,对模型参数进行了识别,对力学模型进行了验证。结果表明:所用阻尼器在拟静态试验过程中阻尼力波动现象显著,无电流时阻尼力随着位移幅值增加而略微减小,有电流时阻尼力随着位移幅值增加而稍微增大;阻尼力随电流的增大明显增大,当电流超过1.5 A时,MRD达到磁饱和状态,阻尼力增幅明显降低;提出的力学模型能够较好地描述拟静力下阻尼力随电流和位移的改变而产生的变化特性。 相似文献
64.
Identification of hydrogen permeability parameters of membrane materials in an aggregated experiment
《International Journal of Hydrogen Energy》2020,45(12):7433-7443
The study of the hydrogen permeability of materials for membrane-based separation/purification technologies employs a variety of experimental methods with their own specific features, advantages and shortfalls. The method of penetration with vacuum pumping allows determining the diffusion coefficient from so-called lag time. The accuracy of the estimation depends on the degree of proximity to the DLR (diffusion limited regime) mode. The method of “communicating vessels” is more sensitive to surface processes. The thermal desorption (TDS) technique permits “scanning” the material dynamically across a wide range of temperatures. “Separate” application of these methods leads to a situation where the materials studied are in fact somewhat different (for example, due to different impacts on the surface), and significant differences in parameter estimates ensue. This paper suggests and implements a technique for a combined three-stage ‹‹penetration (with and without vacuum pumping)+TDS›› experiment and the corresponding mathematical toolkit. The informative capacity of the experiments and the accuracy of the estimation of hydrogen permeability parameters (adsorption, dissolution, diffusion and desorption) of the membrane materials under study are thus enhanced. 相似文献
65.
Hazelnut husk brown rot has been identified as a new disease in Liaoning Province in recent years. The objective of this study as to identify the pathogen. [Method] In this study, a standard sample of hazelnut husk brown rot was collected from Songmudao Base in Dalian City, Liaoning Province. The pathogen was identified by the studies of the morphology, pathogenicity, and analyses of ITS and LSU sequences. The pathogen was isolated and purified, which was confirmed by Koch’s postulates. The symptoms after inoculation were the same as those collected directly from a diseased tree, which showed that it was the pathogenic fungus. The cultural characteristics and conidia and the morphology of the pathogenic fungi were similar to those of Botrytis cinerea’s. The ITS sequences and LSU sequences were compared to the associated strain sequences in GenBank, with 100% identity to Botrytis cinerea (GenBank accession number: MN589848.1) and Botrytis cinerea (GenBank accession number: KU140653.1), respectively. The infection status of the pathogen on the hazelnut husks was also observed. The studies suggested that the pathogen leading to the hazelnut husk brown rot as a new disease in Liaoning Province was Botrytis cinerea. 相似文献
66.
This paper mainly illustrates the Tree Seeds Algorithm (TSA) to tackle structural damage identification problem. The damage model is simulated by the alterations of both stiffness and mass parameters. The objective function is introduced by minimizing the differences between the measured and calculated acceleration data. To enhance the performance of the standard TSA, two modifications including the bare-bones Gaussian updated mechanism and the withering process are introduced. The modified algorithm is named after the BGTSA. In the numerical simulation part, the BGTSA is firstly used to make comparisons with several state-of-the-art algorithms on the CEC05. Secondly, the BGTSA is utilized to deal with the structural damage identification problem by optimizing the acceleration-based nonlinear objective function. Numerical experiments involving a simply supported beam and a truss are carried out to verify the effectiveness of the proposed algorithm. The final results show that with low amount of acceleration data, the BGTSA can acquire better identification results compared with other evolutionary algorithms. Therefore the proposed algorithm could be viewed as a potential tool to solve the structural damage identification problem. 相似文献
67.
This study presents a system identification method based on polynomial modulating function for fractional-order systems with a known time-delay involving input and output noises in the time domain. Based on the polynomial modulating function and fractional-order integration by parts, the identified fractional-order differential equation is transformed into an algebraic equation. By using the numerical integral formula, the least squares form for the system identification is obtained. In order to reduce the effect of noises existing in the input and output measurements, the compensation method for the input and output noises is also studied by introducing an auxiliary high-order fractional-order system in the revised identification algorithm. Finally, the effectiveness of the proposed algorithm is verified by the simulation result of an illustrative example and the experimental result of temperature identification for a thermal system. 相似文献
68.
Isolation and identification of two major acylated anthocyanins from purple sweet potato (Ipomoea batatas L. cultivar Eshu No. 8) by UPLC‐QTOF‐MS/MS and NMR 下载免费PDF全文
Jiu‐Liang Zhang Qing Zhou Zi‐Cheng Zhang 《International Journal of Food Science & Technology》2018,53(8):1932-1941
In recent years, researches on the isolation and preparation of monomeric anthocyanins have intensified because of the requirements of quantitative and structure–bioactivity relationship analyses. However, simple and effective methods about the scale of monomeric anthocyanins from the natural purple sweet potato powder are rarely reported. In this study, high molecular weight acylated monomeric anthocyanins were isolated from purple sweet potato (Ipomoea batatas L. cultivar Eshu No. 8) via the combination of column chromatography and semi‐preparative HPLC technology and identified mainly by ultra‐high‐performance liquid chromatography quadrupole time‐of‐flight tandem mass spectrometry/mass spectrometry (UPLC‐QTOF‐MS/MS) and 1H and 13C nuclear magnetic resonance (NMR). Two major acylated anthocyanins were unambiguously determined as peonidin 3‐O‐(6‐O‐(E)‐caffeoyl‐(2‐O‐(6‐O‐p‐hydroxybenzoyl)‐β‐D‐glucopyranosyl)‐β‐D‐glucopyranoside)‐5‐O‐(β‐D‐glucopyranoside) and peonidin 3‐O‐(6‐O‐(E)‐caffeoyl‐(2‐O‐(6‐O‐(E)‐feruloyl)‐β‐D‐ glucopyranosyl)‐β‐D‐glucopyranoside)‐5‐O‐(β‐D‐glucopyranoside). The results of this study may help promote the purification of high molecular weight acylated anthocyanins from purple sweet potato as well as from other plant materials in nature. 相似文献
69.
Traditional optimization methods, which take a specific order of modal frequency as the design constraint, could fail to obtain the desired solution because of modal substitution. An improved optimization model with continuous sizing variables is established to solve this problem, in which the minimum weight and a given local modal frequency are considered as the objective and the constraint. To capture accurately the expected mode of vibration, a local mode identification technique is proposed based on the strain energy ratio between the local area and the whole structure. With that scheme, an optimization system is developed, in which the local mode can be effectively identified and the constraint can be updated with it in the iteration process. Two numerical examples, of a reinforced plate and a satellite structure, are applied to illustrate the effectiveness and efficacy of the proposed method. 相似文献
70.
Frontiers of Mechanical Engineering - In the process of cutting, the relative vibration between the cutter and the workpiece has an important effect on the surface topography. In this study, the... 相似文献