A factor mining model with optimized random forest for concrete dam deformation monitoring

The unique structure of a dam complicates safety monitoring. Deformation can provide important information about dam evolution. In contrast to model prediction, actual dam response monitoring data can be used for diagnosis and early warning. Given the poor data mining ability of the conventional methods, it is essential to develop a method for extracting the factors influencing a dam. In this study, a data mining method and a model for evaluation of concrete dam deformation were developed using the evidence theory and a random forest. The model has the advantages of being easily understood, visualization with low complexity of training time, and accurate prediction. The model was applied to an actual concrete dam. The results indicated that the proposed random forest model could be used in analysis of concrete dams.     

Group codes on certain algebraic curves with many rational points

We construct a series of algebraic geometric codes using a class of curves which have many rational points. We obtain codes of lengthq ² over _q , whereq = 2q ₀ ² andq ₀ = 2 ⁿ , such that dimension + minimal distance q ² + 1 – q ₀ (q – 1). The codes are ideals in the group algebra _q [S], whereS is a Sylow-2-subgroup of orderq ² of the Suzuki-group of orderq ² (q ² + 1)(q – 1). The curves used for construction have in relation to their genera the maximal number of GF _q -rational points. This maximal number is determined by the explicit formulas of Weil and is effectively smaller than the Hasse—Weil bound.Supported by Deutsche Forschungsgemeinschaft while visiting Essen University     

The impact of risk and protective factors on online teaching experience in high school Italian teachers during the COVID-19 pandemic

The lockdown due to COVID-19 in Italy resulted in the sudden closure of schools, with a shift from traditional teaching to the online one. Through an online questionnaire, this survey explores teachers' experience of online teaching, the level of risk factors (e.g., stress) and protective factors (e.g., locus of control) and their impact on satisfaction levels during the social distancing. One hundred seven high school teachers from Lombardy, an Italian region very affected by the COVID-19 outbreak, participated. Results show that depression and stress are the main predictors of satisfaction levels for online teaching. In addition, coping, locus of control and self-efficacy emerge as important protective factors. Finally, although there is great satisfaction with the online teaching experience, critical elements emerged. This study is relevant because it describes the critical elements of the online teaching experience, and identifies some protective factors and the main risk factors in teachers operating in an area strongly marked by social restrictions imposed by the pandemic. High school teachers emerge as a sub-group of the general population with specific psychological reactions. Considering the results, it is possible to suggest providing high-quality educational support and crisis-psychological oriented services to teachers, and help to maintain the psychological well-being.     

保持几何特征的自适应弹性二次曲线模型

物体形状特征的准确提取往往受到图像获取、目标分割等过程中各种因素的影响,因而需要构造一种鲁棒的形状表现来保有其本质特征。揭示弹性二次曲线(EQW)模型中能量权重因子和样条重叠度因子与形状几何特性间的关系,提出一种自适应保持几何特征的EQW形状表现模型,并将该模型与交互式Live Wire算法相结合,应用至图像分割中,对于各种模态图像中的目标进行分割实验。直观上,本文方法能够在去除噪声同时较好地保持目标形状的显著特征;量化结果方面,交互式分割误差保持在较小稳定范围内,引入EQW模型带来的时间开销亦在可接受范围内。     

阻燃型氢氧化镁制备及其影响因素探讨

以七水硫酸镁为原料、氨水为沉淀剂、选择适宜的表面活性剂。以样品XRD图中（001）面与（101）面衍射峰的相对强弱为考察指标，通过单因素实验，分别考察了反应温度、恒温反应时间、陈化时间、表面活性剂用量及氨镁摩尔比等因素对氢氧化镁样品XRD图中（001）面与（101）面衍射峰相对强弱的影响。实验结果表明，制备阻燃氩氧化镁较适宜的工艺条件为：反应温度40℃、恒温反应时间40min、陈化时间120min、表面活性剂A体积用量4ml、氨镁摩尔比6：1.     

The Role of Tumor Microenvironment Cells in Colorectal Cancer (CRC) Cachexia

Cancer cachexia (CC) is a multifactorial syndrome in patients with advanced cancer characterized by weight loss via skeletal-muscle and adipose-tissue atrophy, catabolic activity, and systemic inflammation. CC is correlated with functional impairment, reduced therapeutic responsiveness, and poor prognosis, and is a major cause of death in cancer patients. In colorectal cancer (CRC), cachexia affects around 50–61% of patients, but remains overlooked, understudied, and uncured. The mechanisms driving CC are not fully understood but are related, at least in part, to the local and systemic immune response to the tumor. Accumulating evidence demonstrates a significant role of tumor microenvironment (TME) cells (e.g., macrophages, neutrophils, and fibroblasts) in both cancer progression and tumor-induced cachexia, through the production of multiple procachectic factors. The most important role in CRC-associated cachexia is played by pro-inflammatory cytokines, including the tumor necrosis factor α (TNFα), originally known as cachectin, Interleukin (IL)-1, IL-6, and certain chemokines (e.g., IL-8). Heterogeneous CRC cells themselves also produce numerous cytokines (including chemokines), as well as novel factors called “cachexokines”. The tumor microenvironment (TME) contributes to systemic inflammation and increased oxidative stress and fibrosis. This review summarizes the current knowledge on the role of TME cellular components in CRC-associated cachexia, as well as discusses the potential role of selected mediators secreted by colorectal cancer cells in cooperation with tumor-associated immune and non-immune cells of tumor microenvironment in inducing or potentiating cancer cachexia. This knowledge serves to aid the understanding of the mechanisms of this process, as well as prevent its consequences.     

水下设备安装过程及其影响因素分析

为了提高水下设备安装精度与工作效率,基于海上工作经验及查阅国内外相关文献,对水下设备的安装过程进行了研究,其总体过程大致分为5个阶段,即装船固定、提升操作、穿越飞溅区、深水下放、落地坐放;分析了影响水下设备安装过程的主要因素,其中水深主要影响吊放系统和设备在水下的横向偏移;波浪载荷主要应用船舶的动态响应,在设备经历穿越飞溅区阶段时对设备及缆绳造成损伤的风险较大;水下设备自身参数主要影响安装方式和安装船舶的选用。     

AA7005铝合金的热加工变形特性

研究了AA7005合金高温压缩变形时的流变应力、动态回复与再结晶以变形组织变化特征。合金稳态变形时,应变速度、温度和流变应力之间满足包含热激活材料常数的Arrhenius项的双曲正弦关系,变形过程为受位错增殖和相互销毁速率控制的热激活过程,螺型位错的交滑移和刃型位错的攀移为主要动态回复机制。动态回复时,形成典型的变形亚晶组织,亚晶尺寸随1nZ的减小而增大。高温低速变形条件下,合金发生局部几何动态再结晶,流变曲线呈现连续下降的特征,形成与原始纤维组织不同的细小等轴大角度再结晶晶粒。     

图像的多尺度几何分析概述*

以函数的稀疏表示为主线,详细介绍了各种多尺度几何分析产生的背景、发展历程和逼近性能,并分析了它们各自存在的优缺点,最后指出了其发展方向.