检索结果-南通市图书馆

Graph CA: Learning From Graph Counterfactual Augmentation for Knowledge Tracing

在线全文

学校读者我要写书评

暂无评论

自动化学报:英文版 2023年第11期10卷 2108-2123页

作者： xinhua wang Shasha Zhao Lei Guo Lei Zhu Chaoran Cui Liancheng Xu School of Information Science and Engineering Shandong Normal UniversityJinan 250358China School of Computer Science and Technology Shandong University of Finance and EconomicsJinan 250014China

With the popularity of online learning in educational settings, knowledge tracing(KT) plays an increasingly significant role. The task of KT is to help students learn more effectively by predicting their next mastery of knowledge based on their historical exercise sequences. Nowadays, many related works have emerged in this field, such as Bayesian knowledge tracing and deep knowledge tracing methods. Despite the progress that has been made in KT, existing techniques still have the following limitations: 1) Previous studies address KT by only exploring the observational sparsity data distribution, and the counterfactual data distribution has been largely ignored. 2) Current works designed for KT only consider either the entity relationships between questions and concepts, or the relations between two concepts, and none of them investigates the relations among students, questions, and concepts, simultaneously, leading to inaccurate student modeling. To address the above limitations,we propose a graph counterfactual augmentation method for knowledge tracing. Concretely, to consider the multiple relationships among different entities, we first uniform students, questions, and concepts in graphs, and then leverage a heterogeneous graph convolutional network to conduct representation *** model the counterfactual world, we conduct counterfactual transformations on students’ learning graphs by changing the corresponding treatments and then exploit the counterfactual outcomes in a contrastive learning framework. We conduct extensive experiments on three real-world datasets, and the experimental results demonstrate the superiority of our proposed Graph CA method compared with several state-of-the-art baselines.

关键词： Contrastive learning counterfactual representation graph neural network knowledge tracing

2005-2021年渭南市丙型肝炎流行特征分析

在线全文

学校读者我要写书评

暂无评论

医学动物防制 2024年第2期40卷 156-160页

作者：樊苏红王新华张义马宁刘刚雷东潮党真渭南市疾病预防控制中心陕西渭南714000 陕西省府谷疾病预防控制中心陕西省疾病预防控制中心

目的通过分析掌握2005-2021年渭南市丙型病毒性肝炎(简称丙肝)的流行特征,为丙肝的防控提供科学意见和建议。方法收集传染病报告信息管理系统的丙肝病例数据,对其进行描述性分析,采用χ2检验对不同性别和年份的丙肝发病率进行比较,用... 详细信息

目的通过分析掌握2005-2021年渭南市丙型病毒性肝炎(简称丙肝)的流行特征,为丙肝的防控提供科学意见和建议。方法收集传染病报告信息管理系统的丙肝病例数据,对其进行描述性分析,采用χ2检验对不同性别和年份的丙肝发病率进行比较,用时间序列模型预测丙肝发病率的变化趋势。结果渭南市丙肝发病率呈先升后降趋势,从2005年的2.65/10万上升至2015年的20.63/10万再下降至2021年的13.96/10万。2005-2021年不同年份丙肝发病率差异有统计学意义(χ^(2)=2 558.131,P80%;各县市区均有丙肝病例报告,发病率较高的地区主要集中在华州区、临渭区、华阴市、潼关县、澄城县。结论渭南市丙肝发病有较明显的人群、空间分布特点,需采取针对性措施,减少疾病的发生和丙型肝炎病毒感染。

关键词：丙型病毒性肝炎流行特征传染病分析

PERFORMANCE ANALYSIS AND KINEMATIC DESIGN OF PURE TRANSLATIONAL PARALLEL MECHANISM WITH VERTICAL GUIDE-WAYS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2006年第2期19卷 300-306页

作者： LI Jianfeng wang xinhua FEI Renyuan LIU Dezhong FAN Jinhong Advanced Manufacturing Technology The Key Laboratory of Beijing Municipality Beijing University of TechnologyBeijing 100022 China College of Mechanical Engineering and Applied Electronically Technology Beijing University of TechnologyBeijing 100022 China

Performance analysis and kinematic design of the 3-PUU pure translational parallel mechanism with vertical guide-ways are investigated. Two novel performance indices, the critical slider stroke and the main section area of workspace, are defined; The expressions of two other indices, i.e. the global dexterity and global force transfer ratio are revised based on the main section of workspace. Using these indices, performance changes versus the varieties of dimensional parameters of mechanism are investigated in detail and the graphic descriptions of change tendencies of the performance indices are illustrated. By means of these obtained graphic descriptions, kinematic parameters for the 3-PUU pure translational parallel mechanism with better characteristics can be directly acquired.

关键词： 3-PUU pure translational parallel mechanism Vertical guide-way Performance analysis Kinematic design

术前NLR、TSH检测预测甲状腺乳头状癌侧区淋巴结转移风险的应用价值

在线全文

学校读者我要写书评

暂无评论

医学研究杂志 2024年第6期53卷 54-58,98页

作者：郭鹏王新华王健夏露花常诚胡峙珩新疆医科大学附属肿瘤医院核医学科乌鲁木齐830011

目的探讨术前中性粒细胞与淋巴细胞比值(neutrophil-to-lymphocyte ratio,NLR)、促甲状腺激素(thyroid stimulating hormone,TSH)在甲状腺乳头状癌(papillary thyroid carcinoma,PTC)预测颈外侧区淋巴结转移风险的价值。方法分析654例PTC患者的临床资料,NLR、TSH及其他血清学指标通过受试者工作特征(receiver operating characteristic,ROC)曲线获得连续变量的截断值。进行二元Logistic回归分析,将独立危险因素纳入Logistic回归模型中,建立列线图。采用C指数及校准曲线评价预后模型的准确性和区分度。采用临床决策分析(clinical decision analysis,DCA)曲线来预测临床应用潜力。结果多因素Logistic回归分析结果显示,术前NLR、TSH、Tg/TSH、T分期、肿瘤灶数为影响PTC患者颈外侧区淋巴结转移的独立危险因素(P<0.05),并构建列线图,C指数为0.730,对该模型进行验证,C指数为0.719,其校准曲线有较好的一致性,DCA曲线表明了良好的临床潜力。结论术前NLR低值组、TSH高值组联合临床其他因素对预测PTC颈外侧区淋巴结转移有重要预测价值。

关键词：甲状腺乳头状癌中性粒细胞与淋巴细胞比值淋巴结转移

Response to seasonal change of insect resources in Changbai Mountain temperate forests by Greater Horseshoe bats

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2010年第22期55卷 2410-2415页

作者： wang Jing METZNER Walter ZHU Xu wang xinhua FENG Jiang Key Laboratory for Wetland Ecology and Vegetation Restoration of National Environmental Protection Northeast Normal University Chang chun 130024 China Key Laboratory of Vegetation Ecology of the Ministry of Education Institute of Grassland Science Northeast Normal University Changchun 130024 China University of California Box 951606 Los Angeles CA 90095-1606 USA College of Zoological Sciences and Technology Jilin Agricultural University Changchun 130118 China

Knowing how bats select different habitats in response to environmental changes provides a framework for anticipating the likely consequences of changes in climate or vegetation. In this study we assessed the presence of greater horseshoe bats (Rhinolophus ferrumequinum) and their foraging behavior. This study depicts an effective approach for seasonal responses of habitat selection by Chiroptera.

关键词：森林昆虫资源大蹄蝠季节变化长白山栖息地选择温带环境变化觅食行为

Characteristics of particulate-bound polycyclic aromatic hydrocarbons emitted from industrial grade biomass boilers

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2016年第2期28卷 28-34页

作者： Xiaoyang Yang Chunmei Geng Xuesong Sun Wen Yang xinhua wang Jianhua Chen State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental Sciences Beijing 100012China Beijing Municipal Research Institute of Environmental Protection Beijing 100037 China

Polycyclic aromatic hydrocarbons（PAHs） are carcinogenic or mutagenic and are important toxic pollutants in the flue gas of boilers. Two industrial grade biomass boilers were selected to investigate the characteristics of particulate-bound PAHs： one biomass boiler retro-fitted from an oil boiler（BB1） and one specially designed（BB2） biomass boiler. One coal-fired boiler was also selected for comparison. By using a dilution tunnel system, particulate samples from boilers were collected and 10 PAH species were analyzed by gas chromatography–mass spectrometry（GC–MS）. The total emission factors（EFs） of PAHs ranged from 0.0064 to0.0380 mg/kg, with an average of 0.0225 mg/kg, for the biomass boiler emission samples. The total PAH EFs for the tested coal-fired boiler were 1.8 times lower than the average value of the biomass boilers. The PAH diagnostic ratios for wood pellets and straw pellets were *** ratio of indeno（1,2,3-cd）pyrene/[indeno（1,2,3-cd）pyrene ＋ benzo（g,h,i）perylene] for the two biomass boilers was lower than those of the reference data for other burning devices, which can probably be used as an indicator to distinguish the emission of biomass boilers from that of industrial coal-fired boilers and residential stoves. The toxic potential of the emission from wood pellet burning was higher than that from straw pellet burning, however both of them were much lower than residential stove exhausts.

关键词： Polycyclic aromatic hydrocarbons Industrial grade biomass boiler Emission factor Diagnostic ratio Potential toxicity risk

EFFECTS OF Al CONTENT ON STRUCTURAL STABILITY AND MAGNETIC PROPERTIES OF Sm_2(Fe,Al)_(17) COMPOUNDS

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 1999年第1期9卷 42-45页

作者： Xu, Rengen wang, xinhua Wu, Jianmin Pan, Hongge Chen, Changpin wang, Qidong Dai, Lichi Zhejiang Univ Hangzhou China

ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｉｓｗｅｌｋｎｏｗｎｔｈａｔＳｍ２Ｆｅ１７Ｎｙｃｏｍｐｏｕｎｄｓｈａｖｅｇｏｏｄｉｎｔｒｉｎｓｉｃｍａｇｎｅｔｉｃｐｒｏｐｅｒｔｉｅｓ［１］．Ｂｅｃａｕｓｅｏｆｔｈｅｐｏｏｒｓｔａｂｉ... 详细信息

ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｉｓｗｅｌｋｎｏｗｎｔｈａｔＳｍ２Ｆｅ１７Ｎｙｃｏｍｐｏｕｎｄｓｈａｖｅｇｏｏｄｉｎｔｒｉｎｓｉｃｍａｇｎｅｔｉｃｐｒｏｐｅｒｔｉｅｓ［１］．ＢｅｃａｕｓｅｏｆｔｈｅｐｏｏｒｓｔａｂｉｌｉｔｙｏｆＳｍ２Ｆｅ１７Ｎｙａｔ...

关键词： Sm 2Fe 17 Al hydride Curie temperature structural stability

Optimal Design of Two-Chamber Gas Distributor with CFD Approach

在线全文

学校读者我要写书评

暂无评论

Journal of Harbin Institute of Technology(New Series) 2015年第2期22卷 79-85页

作者： Dongfang Zhao Fengguo Liu Xueyi You xinhua wang School of Energy and Safety Engineering Tianjin Chengjian University School of Environmental Science and Engineering Tianjin University Tianjin Urban Construction Management and Vocational Technology College

Computational fluid dynamics( CFD) is used to investigate a new type of two-chamber natural gas distributor,which has a natural gas inlet and nine nozzle outlets. The uniformity at the outlet of distributor is practice proven to have significant degree influence on its comprehensive performance. To improve the uniformity at the nozzles of the gas distributor,CFD modeling with the RNG k-ε turbulence model is undertaken to understand the mass flow rate of nozzles with reference to different length of chambers and the most optimal length is obtained. The internal flow pattern of the natural gas distributor is analyzed. It is found that the local maximum deviation of the nozzle outflow rate increases with the increase of chambers length when the length is more than 64 mm. The results provide useful suggestions for the optimal design of two-chamber natural gas distributor.

关键词： gas distributor two-chamber CFD uniformity nozzle mass flow rate

2010—2021年中国居民主要呼吸系统疾病死亡趋势及预测分析

在线全文

学校读者我要写书评

暂无评论

中国预防医学杂志 2024年第7期25卷 845-851页

作者：汪娆娆裴文辉王云超杨震王新华甘肃中医药大学公共卫生学院甘肃兰州730000 甘肃中医药大学基础医学院

目的了解2010—2021年中国居民主要呼吸系统疾病死亡趋势,并对2022—2026年的主要呼吸系统疾病粗死亡率及死亡数进行预测,为开展主要呼吸系统疾病预防工作提供参考依据。方法收集《中国死因监测数据集(2010—2021)》中各死因监测点人口... 详细信息

目的了解2010—2021年中国居民主要呼吸系统疾病死亡趋势,并对2022—2026年的主要呼吸系统疾病粗死亡率及死亡数进行预测,为开展主要呼吸系统疾病预防工作提供参考依据。方法收集《中国死因监测数据集(2010—2021)》中各死因监测点人口及不同性别、年龄、地区和城乡居民的主要呼吸系统疾病死亡数据和人口资料,并用2010年人口普查数据进行标化,通过粗死亡率和标化死亡率描述主要呼吸系统疾病的死亡状况,采用Joinpoint回归模型分析标化死亡率变化趋势,组间率的比较采用χ^(2)检验,并应用灰色模型GM(1,1)预测2022—2026年主要呼吸系统疾病粗死亡率及死亡数。结果中国居民主要呼吸系统疾病的粗死亡率从2010年的70.80/10万下降至2021年的52.58/10万,年度变化百分比(annual percent change,APC)为-2.40%,变化趋势差异有统计学意义(t=-2.12,P=0.034);标化死亡率从2010年的91.42/10万下降至2021年的31.76/10万,变化差异有统计学意义(APC=-9.31%,t=10.17,P<0.01);男性的标化死亡率高于女性,差异有统计学意义(χ^(2)=170384.22,P<0.05),西部地区标化死亡率高于中部地区,中部地区高于东部地区,差异有统计学意义(χ^(2)=123842.02、711633.49,P<0.05),农村标化死亡率高于城市,差异有统计学意义(χ^(2)=577624.53,P<0.05)。主要呼吸系统疾病粗死亡率随年龄增加呈上升趋势(APC=52.76%,P<0.05),≥70岁达高峰。灰色模型GM(1,1)预测结果显示,中国居民2022—2026年主要呼吸系统疾病粗死亡率依次为53.23/10万、51.65/10万、50.13/10万、48.65/10万和47.21/10万,死亡数依次为171012例、174267例、177534例、180813例和184105例。结论2010—2021年中国居民主要呼吸系统疾病存在性别、年龄、地区和城乡差异。其中男性、≥60岁人群、西部地区和农村人群是高危人群,应给予重点关注。

关键词：呼吸系统疾病死亡率趋势分析