Activity based costing (ABC) is a method which can solve many limitations of the traditional cost systems in manufacturing management. In this paper, we investigate how to integrate ABC with workflow technology, and ...Activity based costing (ABC) is a method which can solve many limitations of the traditional cost systems in manufacturing management. In this paper, we investigate how to integrate ABC with workflow technology, and build a workflow meta model supporting ABC. Firstly, the concept and concept model of activity based costing (ABC) are introduced. Next, the meta model of P -PROCE (Process, Product, Resource, Organization, and Cost & Evaluation) is presented. Then the cost meta model is defined by adding ABC to P -PROCE model. Object constraint language (OCL) is used to express meta model and constraints. Finally, we show an enterprise modeling and simulation tool based on the workflow meta model. We can systematically construct an enterprise model and easily and efficiently conduct simulation. Moreover it enables us to analyze and evaluate business processes and its costs.展开更多
目的:创伤后癫痫(post-traumatic epilepsy,PTE)是创伤性脑损伤(traumatic brain injury,TBI)的常见并发症,严重影响患者预后,早期预测PTE风险对临床管理至关重要,相比成人,儿童PTE相关研究较少,且缺乏临床公认的高预测效能模型。本研...目的:创伤后癫痫(post-traumatic epilepsy,PTE)是创伤性脑损伤(traumatic brain injury,TBI)的常见并发症,严重影响患者预后,早期预测PTE风险对临床管理至关重要,相比成人,儿童PTE相关研究较少,且缺乏临床公认的高预测效能模型。本研究旨在构建并验证适用于儿童TBI患者的PTE风险预测列线图模型。方法:系统检索中国知网、万方、中国生物医学文献数据库、维普、Pubmed、Embase和Web of Science数据库中关于儿童PTE危险因素的研究,检索时限为建库至2024年10月。采用Stata 15.0软件进行Meta分析,根据Meta分析结果提取合并效应量具有显著性的风险因素。回顾性收集2019年1月—2023年12月南京医科大学附属儿童医院外科重症监护病房(surgical intensive care unit,SICU)收治的262例TBI患儿,按7∶3比例随机划分为训练队列和内部验证队列,基于Meta分析筛选的危险因素,利用R软件构建多因素Logistic回归模型并绘制列线图。采用受试者工作特征(receiver operating characteristic,ROC)曲线下面积(area under the curve,AUC)评价模型区分度,Hosmer-Lemeshow检验评估校准度,运用决策曲线分析(decision curve analysis,DCA)评估临床实用性。结果:共纳入13项研究,涉及1371819例TBI患儿。Meta分析显示,中国TBI儿童中PTE的发病率为19%(95%CI:17%~20%)。结合Meta分析筛选结果和临床经验,最终纳入8个危险因素构建模型:格拉斯哥昏迷量表(Glasgow coma scale,GCS)评分、开放性脑损伤、早期痫性发作、意识丧失以及异常颅脑影像学表现(颅内血肿、脑挫伤、硬膜下出血、蛛网膜下腔出血),预测模型在训练队列和内部验证队列的AUC分别为0.801(95%CI:0.735~0.867,P<0.05)和0.831(95%CI:0.728~0.934,P<0.05)。Hosmer-Lemeshow拟合优度检验示模型拟合良好(训练队列:P=0.079;验证队列:P=0.082)。DCA显示该模型具有较高临床净获益。结论:本研究基于Meta分析构建的儿童PTE风险预测模型具有良好的区分度、校准度和临床实用性,可作为TBI儿童发生PTE风险评估的有效工具。展开更多
目的运用网状Meta分析评估不同中成药联合化学药治疗甲亢的疗效与安全性,为临床用药提供循证依据。方法计算机检索VIP、Wanfang、CNKI、PubMed、Cochrane Library、Web of Science等数据库,检索公开发表中成药治疗甲亢的对照研究,检索...目的运用网状Meta分析评估不同中成药联合化学药治疗甲亢的疗效与安全性,为临床用药提供循证依据。方法计算机检索VIP、Wanfang、CNKI、PubMed、Cochrane Library、Web of Science等数据库,检索公开发表中成药治疗甲亢的对照研究,检索时限建库至2025年1月。采用Cochrane 5.4手册对纳入的研究进行质量评价。运用R4.1.1软件进行贝叶斯网状Meta数据结果比较及排序。结果最终纳入31篇研究,总样本量2615例,共纳入9种口服中成药。网状Meta分析结果表明,有效率排名前三的干预措施为:百令胶囊+化学药>知柏地黄丸(口服液)+化学药>雷公藤多苷片(多甙片)+化学药;降低FT3激素水平前三排序:雷公藤多苷片(多甙片)+化学药>玄栀颗粒+化学药>甲亢平消丸+化学药;降低FT4激素水平前三排序:雷公藤多苷片(多甙片)+化学药>百令胶囊+化学药>玄栀颗粒+化学药;提高TSH激素水平前三排序:玄栀颗粒+化学药>百令胶囊+化学药>甲亢平消丸+化学药;降低TT3激素水平前三排序:甲亢灵胶囊+化学药>百令胶囊+化学药>知柏地黄丸(口服液)+化学药;降低TT4激素水平前三排序:百令胶囊+化学药>知柏地黄丸(口服液)+化学药>银甲散(丹)+化学药。结论治疗甲状腺功能亢进采用口服中成药的方案中,提高有效率及降低TT4激素水平方面,首选百令胶囊+化学药;针对改善相关激素水平方面,在降低FT3、FT4激素水平方面,雷公藤多苷片(多甙片)+化学药最有效,甲亢灵胶囊+化学药在降低TT3激素水平方面最有效,临床中可根据患者的具体情况合理准确选择用药。展开更多
目的:运用网状Meta分析评估不同免疫吸附柱治疗类风湿关节炎的有效性与安全性,为临床诊治提供循证依据。方法:计算机检索维普、万方、中国知网、PubMed、CBM、CochraneLibrary、Web of Science等数据库,检索公开发表的免疫吸附柱治疗类...目的:运用网状Meta分析评估不同免疫吸附柱治疗类风湿关节炎的有效性与安全性,为临床诊治提供循证依据。方法:计算机检索维普、万方、中国知网、PubMed、CBM、CochraneLibrary、Web of Science等数据库,检索公开发表的免疫吸附柱治疗类风湿关节炎的研究,检索时限至2024年8月。采用Cochrane 5.4手册对纳入的随机对照试验进行质量评价,采用纽卡斯尔-渥太华量表(NOS)对回顾性队列研究进行质量评价。运用R4.1.1软件进行贝叶斯网状Meta分析。结果:最终纳入13篇研究,总样本量891例,共有4种免疫吸附柱。网状Meta分析结果表明,降低C-反应蛋白前3名排序:HA280型吸附柱+常规西药>PH-350型吸附柱+常规西药>A蛋白吸附柱;降低红细胞沉降率前3名排序:白细胞吸附柱>HA280型吸附柱+常规西药>PH-350型吸附柱+常规西药;降低关节肿胀计数前3名排序:白细胞吸附柱>A蛋白吸附柱+常规西药>PH-350型吸附柱+常规西药;降低关节压痛计数前3名排序:白细胞吸附柱>A蛋白吸附柱+常规西药>PH-350型吸附柱+常规西药;降低患者对疾病活动性评分前3名排序:PH-350型吸附柱+常规西药>白细胞吸附柱>A蛋白吸附柱;降低目测类比评分前3名排序:PH-350型吸附柱+常规西药>A蛋白吸附柱>白细胞吸附柱;降低医师对疾病活动性评分前3名排序:PH-350型吸附柱+常规西药>白细胞吸附柱>常规西药。结论:基于纳入的13篇文献证据表明,在降低C-反应蛋白方面,HA280型吸附柱联合常规西药作为首选;在降低红细胞沉降率、关节肿胀计数、关节压痛计数方面,白细胞吸附柱作为首选;在降低患者对疾病活动性评分、医师对疾病活动性评分及目测类比评分方面,PH-350型吸附柱联合常规西药作为首选,在临床中可根据患者的具体情况合理选择不同的免疫吸附柱。展开更多
知识追踪根据学生的历史学习轨迹来实现对其知识掌握水平的实时评估与跟踪,从而预测学生未来的学习表现,是在线学习系统实现个性化学习体验的核心技术之一.与传统方法相比,现有的基于深度神经网络的知识追踪模型取得了显著优势,但其通...知识追踪根据学生的历史学习轨迹来实现对其知识掌握水平的实时评估与跟踪,从而预测学生未来的学习表现,是在线学习系统实现个性化学习体验的核心技术之一.与传统方法相比,现有的基于深度神经网络的知识追踪模型取得了显著优势,但其通常依赖大量训练数据.在学生答题早期,交互数据极度稀缺,所以训练一个复杂、有效的深度知识追踪模型十分具有挑战性.针对此问题,提出一种基于元学习增强的早期知识追踪框架(Meta-Learning-Enhanced Knowledge Tracing,MetaKT).给定目标知识追踪任务和其他若干个相关辅助任务,MetaKT首先在辅助任务上训练模型,然后利用目标任务的数据对预训练后的模型进行微调直至模型收敛.在七个公开数据集上以常用的DKT和DKVMN为基准进行实验,结果发现,提出的MetaKT框架使DKT和DKVMN模型分别在27和33(共35)个测试场景中的AUC(Area under Curve)获得了提升.展开更多
Engineering data are separately organized and their schemas are increasingly complex and variable. Engineering data management systems are needed to be able to manage the unified data and to be both customizable and e...Engineering data are separately organized and their schemas are increasingly complex and variable. Engineering data management systems are needed to be able to manage the unified data and to be both customizable and extensible. The design of the systems is heavily dependent on the flexibility and self-description of the data model. The characteristics of engineering data and their management facts are analyzed. Then engineering data warehouse (EDW) architecture and multi-layer metamodels are presented. Also an approach to manage anduse engineering data by a meta object is proposed. Finally, an application flight test EDW system (FTEDWS) is described and meta-objects to manage engineering data in the data warehouse are used. It shows that adopting a meta-modeling approach provides a support for interchangeability and a sufficiently flexible environment in which the system evolution and the reusability can be handled.展开更多
Architecture framework has become an effective method recently to describe the system of systems(SoS)architecture,such as the United States(US)Department of Defense Architecture Framework Version 2.0(DoDAF2.0).As a vi...Architecture framework has become an effective method recently to describe the system of systems(SoS)architecture,such as the United States(US)Department of Defense Architecture Framework Version 2.0(DoDAF2.0).As a viewpoint in DoDAF2.0,the operational viewpoint(OV)describes operational activities,nodes,and resource flows.The OV models are important for SoS architecture development.However,as the SoS complexity increases,constructing OV models with traditional methods exposes shortcomings,such as inefficient data collection and low modeling standards.Therefore,we propose an intelligent modeling method for five OV models,including operational resource flow OV-2,organizational relationships OV-4,operational activity hierarchy OV-5a,operational activities model OV-5b,and operational activity sequences OV-6c.The main idea of the method is to extract OV architecture data from text and generate interoperable OV models.First,we construct the OV meta model based on the DoDAF2.0 meta model(DM2).Second,OV architecture named entities is recognized from text based on the bidirectional long short-term memory and conditional random field(BiLSTM-CRF)model.And OV architecture relationships are collected with relationship extraction rules.Finally,we define the generation rules for OV models and develop an OV modeling tool.We use unmanned surface vehicles(USV)swarm target defense SoS architecture as a case to verify the feasibility and effectiveness of the intelligent modeling method.展开更多
Parameter identification, model calibration, and uncertainty quantification are important steps in the model-building process, and are necessary for obtaining credible results and valuable information. Sensitivity ana...Parameter identification, model calibration, and uncertainty quantification are important steps in the model-building process, and are necessary for obtaining credible results and valuable information. Sensitivity analysis of hydrological model is a key step in model uncertainty quantification, which can identify the dominant parameters, reduce the model calibration uncertainty, and enhance the model optimization efficiency. There are, however, some shortcomings in classical approaches, including the long duration of time and high computation cost required to quantitatively assess the sensitivity of a multiple-parameter hydrological model. For this reason, a two-step statistical evaluation framework using global techniques is presented. It is based on （1） a screening method （Morris） for qualitative ranking of parameters, and （2） a variance-based method integrated with a meta-model for quantitative sensitivity analysis, i.e., the Sobol method integrated with the response surface model （RSMSobol）. First, the Morris screening method was used to qualitatively identify the parameters＇ sensitivity, and then ten parameters were selected to quantify the sensitivity indices. Subsequently, the RSMSobol method was used to quantify the sensitivity, i.e., the first-order and total sensitivity indices based on the response surface model （RSM） were calculated. The RSMSobol method can not only quantify the sensitivity, but also reduce the computational cost, with good accuracy compared to the classical approaches. This approach will be effective and reliable in the global sensitivity analysis of a complex large-scale distributed hydrological model.展开更多
Conventional trajectory optimization techniques have been challenged by their inability to handle threats with irregular shapes and the tendency to be sensitive to control variations of aircraft. Aiming to overcome th...Conventional trajectory optimization techniques have been challenged by their inability to handle threats with irregular shapes and the tendency to be sensitive to control variations of aircraft. Aiming to overcome these difficulties, this paper presents an alternative approach for trajectory optimization, where the problem is formulated into a parametric optimization of the maneuver variables under a tactics template framework. To reduce the size of the problem, global sensitivity analysis （GSA） is performed to identify the less-influential maneuver variables. The probability collectives （PC） algorithm, which is well-suited to discrete and discontinuous optimization, is applied to solve the trajectory optimization problem. The robustness of the trajectory is assessed through multiple sampling around the chosen values of the maneuver variables. Meta-models based on radius basis function （RBF） are created for evaluations of the means and deviations of the problem objectives and constraints. To guarantee the approximation accuracy, the meta-models are adaptively updated during optimization. The proposed approach is demonstrated on a typical airground attack mission scenario. Results reveal that the proposed approach is capable of generating robust and optimal trajectories with both accuracy and efficiency.展开更多
To investigate the application of meta-model for finite element( FE) model updating of structures,the performance of two popular meta-model,i. e.,Kriging model and response surface model( RSM),were compared in detail....To investigate the application of meta-model for finite element( FE) model updating of structures,the performance of two popular meta-model,i. e.,Kriging model and response surface model( RSM),were compared in detail. Firstly,above two kinds of meta-model were introduced briefly. Secondly,some key issues of the application of meta-model to FE model updating of structures were proposed and discussed,and then some advices were presented in order to select a reasonable meta-model for the purpose of updating the FE model of structures. Finally,the procedure of FE model updating based on meta-model was implemented by updating the FE model of a truss bridge model with the measured modal parameters. The results showed that the Kriging model was more proper for FE model updating of complex structures.展开更多
In this study, a new method for conversion of solid finite element solution to beam finite element solution is developed based on the meta-modeling theory which constructs a model consistent with continuum mechanics. ...In this study, a new method for conversion of solid finite element solution to beam finite element solution is developed based on the meta-modeling theory which constructs a model consistent with continuum mechanics. The proposed method is rigorous and efficient compared to a typical conversion method which merely computes surface integration of solid element nodal stresses to obtain cross-sectional forces. The meta-modeling theory ensures the rigorousness of proposed method by defining a proper distance between beam element and solid element solutions in a function space of continuum mechanics. Results of numerical verification test that is conducted with a simple cantilever beam are used to find the proper distance function for this conversion. Time history analysis of the main tunnel structure of a real ramp tunnel is considered as a numerical example for the proposed conversion method. It is shown that cross-sectional forces are readily computed for solid element solution of the main tunnel structure when it is converted to a beam element solution using the proposed method. Further, envelopes of resultant forces which are of primary importance for the purpose of design, are developed for a given ground motion at the end.展开更多
背景作为脑卒中患者康复效果的重要评定指标之一,社会参与逐渐受到关注,了解脑卒中患者对社会参与的认知和经历有利于帮助脑卒中患者快速康复、回归家庭并重新融入社会,但单一的质性研究结果可能不具有概括性和代表性。目的通过Meta整...背景作为脑卒中患者康复效果的重要评定指标之一,社会参与逐渐受到关注,了解脑卒中患者对社会参与的认知和经历有利于帮助脑卒中患者快速康复、回归家庭并重新融入社会,但单一的质性研究结果可能不具有概括性和代表性。目的通过Meta整合方法系统梳理关于脑卒中患者对社会参与认知和经历的质性研究,为进一步提高脑卒中患者康复效果提供参考。方法使用计算机检索PubMed、Web of Science、Cochrane Library、Embase、心理学文摘(PsycINFO)、护理和联合卫生文献累积索引(CINAHL)、澳大利亚乔安娜布里格斯研究所(JBI)循证卫生保健数据库、中国知网、万方数据知识服务平台、维普网、中国生物医学文献数据库,筛选其自建库至2022年11月以来收录的关于脑卒中患者对社会参与认知和经历的质性研究。采用汇集性Meta整合法对研究主题、隐含意义、分类等研究结果进行Meta整合。结果纳入Meta整合的14篇文献共涉及183例脑卒中患者,通过Meta整合共得出26个研究结果,其中相近结果可归纳为8个新类别,最终归纳出3个整合结果:(1)脑卒中患者对社会参与的认知和经历;(2)脑卒中患者多种社会参与受限且受较多因素影响;(3)多方支持对脑卒中患者社会参与至关重要。结论脑卒中患者对社会参与有新见解,须纠正和消除脑卒中患者对社会参与的自我认同紊乱及其限制因素,并重视脑卒中患者社会参与的多方支持。展开更多
文摘Activity based costing (ABC) is a method which can solve many limitations of the traditional cost systems in manufacturing management. In this paper, we investigate how to integrate ABC with workflow technology, and build a workflow meta model supporting ABC. Firstly, the concept and concept model of activity based costing (ABC) are introduced. Next, the meta model of P -PROCE (Process, Product, Resource, Organization, and Cost & Evaluation) is presented. Then the cost meta model is defined by adding ABC to P -PROCE model. Object constraint language (OCL) is used to express meta model and constraints. Finally, we show an enterprise modeling and simulation tool based on the workflow meta model. We can systematically construct an enterprise model and easily and efficiently conduct simulation. Moreover it enables us to analyze and evaluate business processes and its costs.
文摘目的:创伤后癫痫(post-traumatic epilepsy,PTE)是创伤性脑损伤(traumatic brain injury,TBI)的常见并发症,严重影响患者预后,早期预测PTE风险对临床管理至关重要,相比成人,儿童PTE相关研究较少,且缺乏临床公认的高预测效能模型。本研究旨在构建并验证适用于儿童TBI患者的PTE风险预测列线图模型。方法:系统检索中国知网、万方、中国生物医学文献数据库、维普、Pubmed、Embase和Web of Science数据库中关于儿童PTE危险因素的研究,检索时限为建库至2024年10月。采用Stata 15.0软件进行Meta分析,根据Meta分析结果提取合并效应量具有显著性的风险因素。回顾性收集2019年1月—2023年12月南京医科大学附属儿童医院外科重症监护病房(surgical intensive care unit,SICU)收治的262例TBI患儿,按7∶3比例随机划分为训练队列和内部验证队列,基于Meta分析筛选的危险因素,利用R软件构建多因素Logistic回归模型并绘制列线图。采用受试者工作特征(receiver operating characteristic,ROC)曲线下面积(area under the curve,AUC)评价模型区分度,Hosmer-Lemeshow检验评估校准度,运用决策曲线分析(decision curve analysis,DCA)评估临床实用性。结果:共纳入13项研究,涉及1371819例TBI患儿。Meta分析显示,中国TBI儿童中PTE的发病率为19%(95%CI:17%~20%)。结合Meta分析筛选结果和临床经验,最终纳入8个危险因素构建模型:格拉斯哥昏迷量表(Glasgow coma scale,GCS)评分、开放性脑损伤、早期痫性发作、意识丧失以及异常颅脑影像学表现(颅内血肿、脑挫伤、硬膜下出血、蛛网膜下腔出血),预测模型在训练队列和内部验证队列的AUC分别为0.801(95%CI:0.735~0.867,P<0.05)和0.831(95%CI:0.728~0.934,P<0.05)。Hosmer-Lemeshow拟合优度检验示模型拟合良好(训练队列:P=0.079;验证队列:P=0.082)。DCA显示该模型具有较高临床净获益。结论:本研究基于Meta分析构建的儿童PTE风险预测模型具有良好的区分度、校准度和临床实用性,可作为TBI儿童发生PTE风险评估的有效工具。
文摘目的运用网状Meta分析评估不同中成药联合化学药治疗甲亢的疗效与安全性,为临床用药提供循证依据。方法计算机检索VIP、Wanfang、CNKI、PubMed、Cochrane Library、Web of Science等数据库,检索公开发表中成药治疗甲亢的对照研究,检索时限建库至2025年1月。采用Cochrane 5.4手册对纳入的研究进行质量评价。运用R4.1.1软件进行贝叶斯网状Meta数据结果比较及排序。结果最终纳入31篇研究,总样本量2615例,共纳入9种口服中成药。网状Meta分析结果表明,有效率排名前三的干预措施为:百令胶囊+化学药>知柏地黄丸(口服液)+化学药>雷公藤多苷片(多甙片)+化学药;降低FT3激素水平前三排序:雷公藤多苷片(多甙片)+化学药>玄栀颗粒+化学药>甲亢平消丸+化学药;降低FT4激素水平前三排序:雷公藤多苷片(多甙片)+化学药>百令胶囊+化学药>玄栀颗粒+化学药;提高TSH激素水平前三排序:玄栀颗粒+化学药>百令胶囊+化学药>甲亢平消丸+化学药;降低TT3激素水平前三排序:甲亢灵胶囊+化学药>百令胶囊+化学药>知柏地黄丸(口服液)+化学药;降低TT4激素水平前三排序:百令胶囊+化学药>知柏地黄丸(口服液)+化学药>银甲散(丹)+化学药。结论治疗甲状腺功能亢进采用口服中成药的方案中,提高有效率及降低TT4激素水平方面,首选百令胶囊+化学药;针对改善相关激素水平方面,在降低FT3、FT4激素水平方面,雷公藤多苷片(多甙片)+化学药最有效,甲亢灵胶囊+化学药在降低TT3激素水平方面最有效,临床中可根据患者的具体情况合理准确选择用药。
文摘目的:运用网状Meta分析评估不同免疫吸附柱治疗类风湿关节炎的有效性与安全性,为临床诊治提供循证依据。方法:计算机检索维普、万方、中国知网、PubMed、CBM、CochraneLibrary、Web of Science等数据库,检索公开发表的免疫吸附柱治疗类风湿关节炎的研究,检索时限至2024年8月。采用Cochrane 5.4手册对纳入的随机对照试验进行质量评价,采用纽卡斯尔-渥太华量表(NOS)对回顾性队列研究进行质量评价。运用R4.1.1软件进行贝叶斯网状Meta分析。结果:最终纳入13篇研究,总样本量891例,共有4种免疫吸附柱。网状Meta分析结果表明,降低C-反应蛋白前3名排序:HA280型吸附柱+常规西药>PH-350型吸附柱+常规西药>A蛋白吸附柱;降低红细胞沉降率前3名排序:白细胞吸附柱>HA280型吸附柱+常规西药>PH-350型吸附柱+常规西药;降低关节肿胀计数前3名排序:白细胞吸附柱>A蛋白吸附柱+常规西药>PH-350型吸附柱+常规西药;降低关节压痛计数前3名排序:白细胞吸附柱>A蛋白吸附柱+常规西药>PH-350型吸附柱+常规西药;降低患者对疾病活动性评分前3名排序:PH-350型吸附柱+常规西药>白细胞吸附柱>A蛋白吸附柱;降低目测类比评分前3名排序:PH-350型吸附柱+常规西药>A蛋白吸附柱>白细胞吸附柱;降低医师对疾病活动性评分前3名排序:PH-350型吸附柱+常规西药>白细胞吸附柱>常规西药。结论:基于纳入的13篇文献证据表明,在降低C-反应蛋白方面,HA280型吸附柱联合常规西药作为首选;在降低红细胞沉降率、关节肿胀计数、关节压痛计数方面,白细胞吸附柱作为首选;在降低患者对疾病活动性评分、医师对疾病活动性评分及目测类比评分方面,PH-350型吸附柱联合常规西药作为首选,在临床中可根据患者的具体情况合理选择不同的免疫吸附柱。
文摘知识追踪根据学生的历史学习轨迹来实现对其知识掌握水平的实时评估与跟踪,从而预测学生未来的学习表现,是在线学习系统实现个性化学习体验的核心技术之一.与传统方法相比,现有的基于深度神经网络的知识追踪模型取得了显著优势,但其通常依赖大量训练数据.在学生答题早期,交互数据极度稀缺,所以训练一个复杂、有效的深度知识追踪模型十分具有挑战性.针对此问题,提出一种基于元学习增强的早期知识追踪框架(Meta-Learning-Enhanced Knowledge Tracing,MetaKT).给定目标知识追踪任务和其他若干个相关辅助任务,MetaKT首先在辅助任务上训练模型,然后利用目标任务的数据对预训练后的模型进行微调直至模型收敛.在七个公开数据集上以常用的DKT和DKVMN为基准进行实验,结果发现,提出的MetaKT框架使DKT和DKVMN模型分别在27和33(共35)个测试场景中的AUC(Area under Curve)获得了提升.
文摘Engineering data are separately organized and their schemas are increasingly complex and variable. Engineering data management systems are needed to be able to manage the unified data and to be both customizable and extensible. The design of the systems is heavily dependent on the flexibility and self-description of the data model. The characteristics of engineering data and their management facts are analyzed. Then engineering data warehouse (EDW) architecture and multi-layer metamodels are presented. Also an approach to manage anduse engineering data by a meta object is proposed. Finally, an application flight test EDW system (FTEDWS) is described and meta-objects to manage engineering data in the data warehouse are used. It shows that adopting a meta-modeling approach provides a support for interchangeability and a sufficiently flexible environment in which the system evolution and the reusability can be handled.
基金National Natural Science Foundation of China(71690233,71971213,71901214)。
文摘Architecture framework has become an effective method recently to describe the system of systems(SoS)architecture,such as the United States(US)Department of Defense Architecture Framework Version 2.0(DoDAF2.0).As a viewpoint in DoDAF2.0,the operational viewpoint(OV)describes operational activities,nodes,and resource flows.The OV models are important for SoS architecture development.However,as the SoS complexity increases,constructing OV models with traditional methods exposes shortcomings,such as inefficient data collection and low modeling standards.Therefore,we propose an intelligent modeling method for five OV models,including operational resource flow OV-2,organizational relationships OV-4,operational activity hierarchy OV-5a,operational activities model OV-5b,and operational activity sequences OV-6c.The main idea of the method is to extract OV architecture data from text and generate interoperable OV models.First,we construct the OV meta model based on the DoDAF2.0 meta model(DM2).Second,OV architecture named entities is recognized from text based on the bidirectional long short-term memory and conditional random field(BiLSTM-CRF)model.And OV architecture relationships are collected with relationship extraction rules.Finally,we define the generation rules for OV models and develop an OV modeling tool.We use unmanned surface vehicles(USV)swarm target defense SoS architecture as a case to verify the feasibility and effectiveness of the intelligent modeling method.
基金supported by the National Natural Science Foundation of China (Grant No. 41271003)the National Basic Research Program of China (Grants No. 2010CB428403 and 2010CB951103)
文摘Parameter identification, model calibration, and uncertainty quantification are important steps in the model-building process, and are necessary for obtaining credible results and valuable information. Sensitivity analysis of hydrological model is a key step in model uncertainty quantification, which can identify the dominant parameters, reduce the model calibration uncertainty, and enhance the model optimization efficiency. There are, however, some shortcomings in classical approaches, including the long duration of time and high computation cost required to quantitatively assess the sensitivity of a multiple-parameter hydrological model. For this reason, a two-step statistical evaluation framework using global techniques is presented. It is based on （1） a screening method （Morris） for qualitative ranking of parameters, and （2） a variance-based method integrated with a meta-model for quantitative sensitivity analysis, i.e., the Sobol method integrated with the response surface model （RSMSobol）. First, the Morris screening method was used to qualitatively identify the parameters＇ sensitivity, and then ten parameters were selected to quantify the sensitivity indices. Subsequently, the RSMSobol method was used to quantify the sensitivity, i.e., the first-order and total sensitivity indices based on the response surface model （RSM） were calculated. The RSMSobol method can not only quantify the sensitivity, but also reduce the computational cost, with good accuracy compared to the classical approaches. This approach will be effective and reliable in the global sensitivity analysis of a complex large-scale distributed hydrological model.
基金supported by Open Research Foundation of Science and Technology on Aerospace Flight Dynamics Laboratory (No. 2012afd1010)
文摘Conventional trajectory optimization techniques have been challenged by their inability to handle threats with irregular shapes and the tendency to be sensitive to control variations of aircraft. Aiming to overcome these difficulties, this paper presents an alternative approach for trajectory optimization, where the problem is formulated into a parametric optimization of the maneuver variables under a tactics template framework. To reduce the size of the problem, global sensitivity analysis （GSA） is performed to identify the less-influential maneuver variables. The probability collectives （PC） algorithm, which is well-suited to discrete and discontinuous optimization, is applied to solve the trajectory optimization problem. The robustness of the trajectory is assessed through multiple sampling around the chosen values of the maneuver variables. Meta-models based on radius basis function （RBF） are created for evaluations of the means and deviations of the problem objectives and constraints. To guarantee the approximation accuracy, the meta-models are adaptively updated during optimization. The proposed approach is demonstrated on a typical airground attack mission scenario. Results reveal that the proposed approach is capable of generating robust and optimal trajectories with both accuracy and efficiency.
基金Sponsored by the National Key Technology Research and Development Program of China(Grant No.2011BAK02B02)
文摘To investigate the application of meta-model for finite element( FE) model updating of structures,the performance of two popular meta-model,i. e.,Kriging model and response surface model( RSM),were compared in detail. Firstly,above two kinds of meta-model were introduced briefly. Secondly,some key issues of the application of meta-model to FE model updating of structures were proposed and discussed,and then some advices were presented in order to select a reasonable meta-model for the purpose of updating the FE model of structures. Finally,the procedure of FE model updating based on meta-model was implemented by updating the FE model of a truss bridge model with the measured modal parameters. The results showed that the Kriging model was more proper for FE model updating of complex structures.
文摘In this study, a new method for conversion of solid finite element solution to beam finite element solution is developed based on the meta-modeling theory which constructs a model consistent with continuum mechanics. The proposed method is rigorous and efficient compared to a typical conversion method which merely computes surface integration of solid element nodal stresses to obtain cross-sectional forces. The meta-modeling theory ensures the rigorousness of proposed method by defining a proper distance between beam element and solid element solutions in a function space of continuum mechanics. Results of numerical verification test that is conducted with a simple cantilever beam are used to find the proper distance function for this conversion. Time history analysis of the main tunnel structure of a real ramp tunnel is considered as a numerical example for the proposed conversion method. It is shown that cross-sectional forces are readily computed for solid element solution of the main tunnel structure when it is converted to a beam element solution using the proposed method. Further, envelopes of resultant forces which are of primary importance for the purpose of design, are developed for a given ground motion at the end.
文摘背景作为脑卒中患者康复效果的重要评定指标之一,社会参与逐渐受到关注,了解脑卒中患者对社会参与的认知和经历有利于帮助脑卒中患者快速康复、回归家庭并重新融入社会,但单一的质性研究结果可能不具有概括性和代表性。目的通过Meta整合方法系统梳理关于脑卒中患者对社会参与认知和经历的质性研究,为进一步提高脑卒中患者康复效果提供参考。方法使用计算机检索PubMed、Web of Science、Cochrane Library、Embase、心理学文摘(PsycINFO)、护理和联合卫生文献累积索引(CINAHL)、澳大利亚乔安娜布里格斯研究所(JBI)循证卫生保健数据库、中国知网、万方数据知识服务平台、维普网、中国生物医学文献数据库,筛选其自建库至2022年11月以来收录的关于脑卒中患者对社会参与认知和经历的质性研究。采用汇集性Meta整合法对研究主题、隐含意义、分类等研究结果进行Meta整合。结果纳入Meta整合的14篇文献共涉及183例脑卒中患者,通过Meta整合共得出26个研究结果,其中相近结果可归纳为8个新类别,最终归纳出3个整合结果:(1)脑卒中患者对社会参与的认知和经历;(2)脑卒中患者多种社会参与受限且受较多因素影响;(3)多方支持对脑卒中患者社会参与至关重要。结论脑卒中患者对社会参与有新见解,须纠正和消除脑卒中患者对社会参与的自我认同紊乱及其限制因素,并重视脑卒中患者社会参与的多方支持。
