Torii: An aspect-based sentiment analysis system that can mine conditions

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.     

SBP-SAT方法及其在波动领域的应用

基于分部求和(Summation By Parts)方法和同时逼近项(Simultaneous Approximation Terms)技术建立的有限差分方法,具有更高的精度和稳定性。同时在介质几何不连续、参数突变条件具有较大的优势。国内对SBP-SAT方法的相关研究目前较少,论文对该方法的研究背景,方法发展过程进行了介绍并基于SBP-SAT方法和弹性波动理论,结合初边值条件,推导出曲线网格条件下的弹性波动SBP-SAT离散方程。最后,通过数值模拟实现地震波传播过程,介绍该方法在地震数值模拟领域中的应用价值和前景。     

惯性导航设备升沉数据测试系统研究

研制了一套基于STM32单片机与单轴摇摆台的测试系统,利用固定圆心、固定半径条件下的圆内三角形关系,通过拉线传感器采集单轴摇摆台复合运动中的升沉数据;同时,对惯性导航设备输出的升沉数据进行采集与处理。对测试系统输出的升沉数据进行了验证,实验结果表明:该测试系统的测试数据准确合理,可实现对惯性导航设备升沉参数的动态测试,弥补了现有同类测试系统的结构复杂、量程小等不足。     

碱铝硅酸盐玻璃化学强化关键影响因素概述

化学强化是一种玻璃机械强度增强方法,适用于异型、超薄、高碱、高膨胀玻璃增强,因新型超薄显示产品的屏幕保护玻璃发展需要,化学强化技术重新在碱铝硅酸盐玻璃品种掀起研究热潮。本文对化学强化本质及铝硅酸盐玻璃在屏幕保护玻璃应用进行了回顾,基于玻璃化学强化的高CS、DOL和低CT诉求,归纳总结了关键影响因素,第1,碱铝硅酸盐玻璃的成分及结构是基础,氧化铝有利玻璃网络孔隙增大创造交换通道,氧化钠或氧化锂是离子交换关键物质;第2,对于玻璃组成和结构设计,要求玻璃网络键合度R=O/Si或O/(Si+Al)满足2.15~2.40,碱金属氧化物质量分数大于13%且膨胀系数大于6×10^-6/℃;第3,在化学强化工艺方面,化学强化温度决定离子扩散系数,化学强化时间决定DOL,一步法仅能获得相对较大的CS,而DOL不很理想,只有两种离子参与交换的二步法才有利于CS和DOL同步提高。     

里程计辅助的高精度车载GNSS/INS组合导航系统

针对城市隧道、偏远山区等复杂路况下,卫星导航系统信号被遮挡较严重或无卫星导航系统信号的场景中,车载GNSS/INS组合导航系统精度下降的问题,提出一种里程计辅助的高精度车载GNSS/INS组合导航方法。该方法中的组合滤波模式可根据载车环境变化在GNSS/INS组合模式和DR/INS组合模式间实现自适应切换,该组合导航方法将三维里程计航位推算位置误差作为状态量扩充到常规组合导航滤波器中,里程计的标度因数误差、安装角误差可通过里程计误差标定方法离线精确得到,后续使用只需将里程计误差参数装订到组合导航系统中即可。车载试验表明,7 km的信号遮挡场景下组合导航系统单个方向上的位置误差最大值也不大于8 m,整个跑车过程中位置误差在3 m以内,进一步保证了车载GNSS/INS组合导航系统复杂路况下的高精度定位。     

非平稳条件下基于贝叶斯网络的内涝风险评估和管理方法

受非平稳条件因素(如气候变化、城市化)的影响,近几年内涝灾害频发。以Z市某地块为研究区域,借助地理信息系统(ArcGIS)和暴雨雨洪管理模型(SWMM)实现研究区排水管网的水动力模拟。在不同降雨情境下,比较分析现状系统及不同改造方案下的系统溢流量等信息,计算内涝风险指数。采用贝叶斯网络分析工具(Bayes Server)对引发内涝风险的主要因素进行推理、识别和分析,进而构建内涝风险评估模型。该模型便于决策者根据设计需求,结合各因素的不确定性范围和发生概率值,综合选取最适合的改造措施,优化市政排水防涝规划,为市政基础设施建设提供了依据。     

鄂尔多斯盆地延长气田马家沟组成藏条件分析

鄂尔多斯盆地马家沟组富含天然气,对其成藏条件进行研究,可很好的指导该区域天然气的勘探开发。本文以延长气田为例从烃源岩、储集层、盖层等方面分析了该区域天然气气藏形成的地质条件。     

Inline Spectroscopy-Based Optimization of Chemical Reactions Considering Dynamic Process Conditions

The demand for sustainable energy sources, like biomass, solar energy, hydro and wind power, is connected to challenges like energy storage and fluctuating energy supply. Regarding the second challenge, industry has to evolve their existing processes from steady state processes to dynamic ones. This work is concerned with the conception of an inline spectroscopy-based optimization routine for chemical reactions under dynamic process conditions, which implements the search for a well applicable optimization algorithm. The studied reaction to reach this goal is a nitroaldol condensation.     

Novel method of constructing generalized Hoberman sphere mechanisms based on deployment axes

This study proposes a method of constructing type II generalized angulated elements (GAEs II) Hoberman sphere mechanisms on the basis of deployment axes that intersect at one point. First, the constraint conditions for inserting n GAEs II into n deployment axes to form a loop are given. The angle constraint conditions of the deployment axes are obtained through a series of linear equations. Second, the connection conditions of two GAEs II loops that share a common deployable center are discussed. Third, a flowchart of constructing the generalized Hoberman sphere mechanism on the basis of deployment axes is provided. Finally, four generalized Hoberman sphere mechanisms based on a fully enclosed regular hexahedron, arithmetic sequence axes, orthonormal arithmetic sequence axes, and spiral-like axes are constructed in accordance with the given arrangement of deployment axes that satisfy the constraint conditions to verify the feasibility of the proposed method.     

Cu-K/Al2O3 based catalysts for conversion of carbon dioxide to methane and carbon monoxide

Abstract

A series of Cu-K/Al₂O₃ catalysts were synthesized by wet impregnation technique. The reduced catalysts were further used for conversion of carbon dioxide to methane and carbon monoxide. Moreover, the fresh and used catalysts were characterized to investigate the changes in the surface morphology, metal dispersion, surface area, crystalline phases, and functional groups of studied catalysts. The SEM analysis of fresh and spent catalysts showed no remarkable difference in surface morphology with irregular shaped agglomerated particles. Furthermore, TEM micrographs presented the well distribution of metal catalyst over alumina support. The decrease in surface area from 115 to 77?m²/g for Cu_1.62-K_0.5/Al₂O₃ after reaction was related to sintering and oxidation of catalyst during reaction. XRD revealed the disappearance of some minor peaks which can be associated with the sintering of spent catalyst. FTIR also presented some new peak for spent catalyst which can be linked with metal oxides. Moreover, various reaction conditions of temperature (230, 400, and 600?°C), pressure (1 and 7?bar), and feed molar ratio of H₂/CO₂ (2:1 and 4:1) were investigated using different Cu loading (0, 1, 1.25, 1.62, and 4 weight percent). A maximum CO₂ conversion of 63% with 39% CH₄ selectivity was achieved by using Cu_1.62-K_0.5/Al₂O₃ at 600?°C, molar ratio of H₂/CO₂ 4 under 7?bar. The presence of K on the surface of synthesized catalyst increased the CO₂ conversion from 48% (Cu₁/Al₂O₃) to 55% (Cu₁-K_0.5/Al₂O₃) at above mentioned reaction conditions which suggested the promoter effect of K during conversion of carbon dioxide.