期刊文献+
共找到14篇文章
< 1 >
每页显示 20 50 100
基于能量优化的数据参数化方法
1
作者 李锋 张彩明 《计算机工程与科学》 CSCD 2006年第5期101-104,共4页
构造一条通过一组给定数据点的参数样条曲线的关键之一是选取节点。本文提出了一种基于离散能量模型的确定节点参数的新方法,该方法首先通过极小化离散能量模型的目标函数确定参数样条曲线在节点处的最佳切向角,然后以最佳切向角为参变... 构造一条通过一组给定数据点的参数样条曲线的关键之一是选取节点。本文提出了一种基于离散能量模型的确定节点参数的新方法,该方法首先通过极小化离散能量模型的目标函数确定参数样条曲线在节点处的最佳切向角,然后以最佳切向角为参变量来计算节点参数。该方法所得到的方程为线性方程,便于求解。本文最后通过实例对新方法与累加弦长方法、向心参数化方法、修正弦长参数化方法以及ZCM方法进行了比较。 展开更多
关键词 双圆弧插值 离散能量模型 最优切向角 数据参数化
下载PDF
基于实时参数化数据的应答器报文智能管理系统 被引量:3
2
作者 徐华沙 劳烁业 《铁路通信信号工程技术》 2023年第10期1-5,36,共6页
为提升目前应答器设备配套使用的维护手段,改进应答器报文系统管理的以人工操作为主的方法,不断提高管理效率,对应答器报文管理工作进行研究,简要说明应答器报文管理系统的主要功能和作用;分析应答器报文管理系统的总体需求,提出总体设... 为提升目前应答器设备配套使用的维护手段,改进应答器报文系统管理的以人工操作为主的方法,不断提高管理效率,对应答器报文管理工作进行研究,简要说明应答器报文管理系统的主要功能和作用;分析应答器报文管理系统的总体需求,提出总体设计方案,并详细阐述应答器报文管理系统的网络结构设计和功能模块划分;描述实现该软件的相关技术和具体的数据结构、模块功能、操作界面等内容。通过设计基于实时参数化数据的应答器报文智能管理系统,实现以铁路局统一管理,各级电务人员在“云-边”协同架构下进行应答器报文动态运用管理的全流程应答器报文安全管理体系,为高速铁路列车安全运行提供可靠保证。 展开更多
关键词 高速铁路 应答器报文 参数数据 报文管理
下载PDF
基于广义基曲面参数化的N边域曲面重构
3
作者 曲学军 张璐 《计算机仿真》 CSCD 北大核心 2010年第7期358-361,369,共5页
研究了由散乱数据点集重构N边域曲面的方法。已有方法大都使用单张B样条曲面进行拟合,或由用户手工描绘曲面片的边界曲线网格。与之不同,为便于数字处理,采用广义基曲面参数化方法可以在建立曲面片网格同时进行散乱数据的参数化,全过程... 研究了由散乱数据点集重构N边域曲面的方法。已有方法大都使用单张B样条曲面进行拟合,或由用户手工描绘曲面片的边界曲线网格。与之不同,为便于数字处理,采用广义基曲面参数化方法可以在建立曲面片网格同时进行散乱数据的参数化,全过程无需人工干预。另外,推导了在曲面拟合算法中控制顶点约束的确定方法以满足给定的边界条件。通过仿真,研究了曲面片网格的光顺以在N边域曲面内部达到G^1连续,并以实例证明了文中算法的有效性。 展开更多
关键词 曲面重构 曲面 散乱数据参数化 曲面光顺
下载PDF
参数化绘图中数据转换方法的探讨
4
作者 胡鹏 《山西建筑》 2013年第16期254-256,共3页
从应用较广的辅助设计绘图软件CAD与不同格式参数间的对接入手,介绍了它们之间数据交换的不同方法,指出利用这些方法对提高辅助设计绘图效率、充分发挥不同工程软件的优势进行协同工作具有很好的帮助作用。
关键词 参数绘图 VLisp 数据转换
下载PDF
智能化煤矿数据仓库建模方法 被引量:12
5
作者 王霖 方乾 +3 位作者 张晓霞 苏上海 施展 王雅琨 《工矿自动化》 北大核心 2022年第4期5-13,共9页
煤矿海量数据存在“数据孤岛”、关联性弱、因缺乏数据管理体系而导致数据质量差等问题,难以充分利用,无法为煤矿智能化提供分析决策支撑。数据仓库可满足煤矿多源异构数据集成需求,为煤矿智能化应用提供数据基础。通过分析煤矿数据类... 煤矿海量数据存在“数据孤岛”、关联性弱、因缺乏数据管理体系而导致数据质量差等问题,难以充分利用,无法为煤矿智能化提供分析决策支撑。数据仓库可满足煤矿多源异构数据集成需求,为煤矿智能化应用提供数据基础。通过分析煤矿数据类型、特点及实际数据智能化应用需求,研究了智能化煤矿数据仓库建模方法。首先,构建了智能化煤矿数据仓库分层架构,分析了原始数据层、明细数据层、基础指标层、服务数据层、公共维度层数据模型特点;其次,以综采工作面数据为例,从业务数据分析、应用需求分析、分层架构设计等方面阐述了数据仓库建模过程;再次,介绍了煤矿数据仓库中数据模型构建方法,即通过维度对齐、维度关联、维度化指标聚合等将原始数据转换为数据仓库维度模型,解决了不同维度的煤矿数据关联应用问题;最后,为解决煤矿数据仓库的可迁移性问题,提出了煤炭行业通用数据仓库+参数化ETL(抽取、转换、加载)方法的煤矿参数化数据仓库设计思路。在实验室环境下搭建了煤矿数据仓库平台,对山西天地王坡煤业有限公司综采工作面数据进行处理,并基于处理数据辅助机理模型分析、实现可视化管理驾驶舱,验证了智能化煤矿数据仓库的实用性;对比了原始数据模型与智能化煤矿数据仓库的性能指标,结果表明智能化煤矿数据仓库的数据组织度、模型复用度和迭代难易度均优于原始数据模型,且数据查询响应时间缩短50%以上。 展开更多
关键词 智能煤矿 煤矿大数据 数据仓库 数据模型 参数数据仓库 维度对齐 维度关联
下载PDF
叶片高质量造型方法研究 被引量:24
6
作者 白瑀 张定华 +2 位作者 任军学 刘维伟 顾学民 《机械科学与技术》 CSCD 北大核心 2003年第3期447-449,共3页
通过对叶片自由曲面造型方法的研究 ,分析了现有造型方法中的若干曲面质量缺陷 ,指出了导致曲面质量缺陷的根本原因。以从截面线计算叶片截面中弧线和厚度分布曲线算法为基础 ,提出一种数据点参数化方法 ,实现了保证厚度特征的叶片高质... 通过对叶片自由曲面造型方法的研究 ,分析了现有造型方法中的若干曲面质量缺陷 ,指出了导致曲面质量缺陷的根本原因。以从截面线计算叶片截面中弧线和厚度分布曲线算法为基础 ,提出一种数据点参数化方法 ,实现了保证厚度特征的叶片高质量造型方法 。 展开更多
关键词 叶片 中弧线 厚度分布曲线 数据参数 拟合
下载PDF
Reduction of distortion and improvement of efficiency for gridding of scattered gravity and magnetic data 被引量:1
7
作者 张晨 姚长利 +3 位作者 谢永茂 郑元满 关胡良 洪东明 《Applied Geophysics》 SCIE CSCD 2012年第4期378-390,494,共14页
This paper presents a reasonable gridding-parameters extraction method for setting the optimal interpolation nodes in the gridding of scattered observed data. The method can extract optimized gridding parameters based... This paper presents a reasonable gridding-parameters extraction method for setting the optimal interpolation nodes in the gridding of scattered observed data. The method can extract optimized gridding parameters based on the distribution of features in raw data. Modeling analysis proves that distortion caused by gridding can be greatly reduced when using such parameters. We also present some improved technical measures that use human- machine interaction and multi-thread parallel technology to solve inadequacies in traditional gridding software. On the basis of these methods, we have developed software that can be used to grid scattered data using a graphic interface. Finally, a comparison of different gridding parameters on field magnetic data from Ji Lin Province, North China demonstrates the superiority of the proposed method in eliminating the distortions and enhancing gridding efficiency. 展开更多
关键词 Scattered data gridding parameters analysis of distribution features human-machine interaction multi-thread parallel technology
下载PDF
Molecular reconstruction model based on structure oriented lumping and group contribution methods 被引量:7
8
作者 Jincai Chen Zhou Fang Tong Qiu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第8期1677-1683,共7页
Molecular management is a promising technology to face challenges in the refining industry, such as more stringent requirements for product oil and heavier crude oil, and to maximize the value of every molecule in pet... Molecular management is a promising technology to face challenges in the refining industry, such as more stringent requirements for product oil and heavier crude oil, and to maximize the value of every molecule in petroleum fractions. To achieve molecular management in refining processes, a novel model that is based on structure oriented lumping(SOL) and group contribution(GC) methods was proposed in this study. SOL method was applied to describe a petroleum fraction with structural increments, and GC method aimed to estimate molecular properties. The latter was achieved by associating rules between SOL structural increments and GC structures. A three-step reconstruction algorithm was developed to build a representative set of molecules from partial analytical data. First, structural distribution parameters were optimized with several properties. Then, a molecular library was created by using the optimized parameters. In the final step, maximum information entropy(MIE) method was applied to obtain a molecular fraction. Two industrial samples were used to validate the method, and the simulation results of the feedstock properties agreed well with the experimental data. 展开更多
关键词 Molecular reconstruction Structure oriented lumping Group contribution Monte Carlo Maximum information entropy
下载PDF
Effects of wind input and wave dissipation formulations on the steady Ekman current solution
9
作者 徐俊丽 宋金宝 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2014年第3期709-719,共11页
The effects of different wind input and wave dissipation formulations on the steady Ekman current solution are described. Two formulations are considered: one from the wave modeling(WAM) program proposed by Hasselmann... The effects of different wind input and wave dissipation formulations on the steady Ekman current solution are described. Two formulations are considered: one from the wave modeling(WAM) program proposed by Hasselmann and Komen and the other provided by Tsagareli and Babanin. The solution adopted for our study was presented by Song for the wave-modifi ed Ekman current model that included the Stokes drift, wind input, and wave dissipation with eddy viscosity increasing linearly with depth. Using the Combi spectrum with tail effects, the solutions are calculated using two formulations for wind input and wave dissipation, and compared. Differences in the results are not negligible. Furthermore, the solution presented by Song and Xu for the eddy viscosity formulated using the K-Profi le Parameterization scheme under wind input and wave dissipation given by Tsagareli and Babanin is compared with that obtained for a depth-dependent eddy viscosity. The solutions are further compared with the available well-known observational data. The result indicates that the Tsagareli and Babanin scheme is more suitable for use in the model when capillary waves are included, and the solution calculated using the K-Profi le Parameterization scheme agrees best with observations. 展开更多
关键词 Combi spectrum Stokes drift wind input wave dissipation steady Ekman current solution
原文传递
巧妙的振动——采用科氏互补(Coriolis)系统进行多变量的流量测量
10
作者 KarinEichkorn 《流程工业》 2003年第8期36-37,共2页
如果一家生产厂商可以精确地测定其物料流量并且准确地按照配方计量配料的话。他就可以降低其装置的操作成本.因为这样可以减少废品,提高收率。事实证明.按照科氏互补原理工作的测量仪器可以精确和可靠地测定物料质量。在近几年来这... 如果一家生产厂商可以精确地测定其物料流量并且准确地按照配方计量配料的话。他就可以降低其装置的操作成本.因为这样可以减少废品,提高收率。事实证明.按照科氏互补原理工作的测量仪器可以精确和可靠地测定物料质量。在近几年来这种传感器的应用大量增加,因为越来越多的用户认识到了这种测量原理的快速.不需维修和在很大程度上不受环境影响的优点。本文阐述了这种测量仪器的功能和作用原理。 展开更多
关键词 流量测量 传感器 零点稳定性 分析鉴定 振动数据 参数数据 Promass测量仪器 科氏互补原理
下载PDF
A data assimilation-based method for optimizing parameterization schemes in a land surface process model 被引量:2
11
作者 ZHANG ShengLei CHEN LiangFu +1 位作者 SU Lin JIA Li 《Science China Earth Sciences》 SCIE EI CAS CSCD 2015年第12期2220-2235,共16页
Optimizing the parameters of a land surface process model(LSPM) through data assimilation(DA) can not only improve and perfect the parameterization schemes in the LSPM through the physical mechanism, but also increase... Optimizing the parameters of a land surface process model(LSPM) through data assimilation(DA) can not only improve and perfect the parameterization schemes in the LSPM through the physical mechanism, but also increase its regional adaptability and simulation capability. This has practical importance for improving simulation results and the climate-prediction capability of general circulation models(GCMs) and regional climate models(RCMs). This paper presents a DA-based method for optimizing the parameterization schemes in LSPMs. We optimize the unsaturated-soil water flow(Un SWF) model as an example by developing a soil-moisture assimilation scheme based on the Un SWF model and the extended Kalman filter(EKF) algorithm, and then combining them with the Variable Infiltration Capacity(VIC) model. Using a month as the assimilation window, we used the Shuffled Complex Evolution–University of Arizona(SCE-UA) algorithm to minimize the objective function through simulated and assimilated soil moisture, achieved the best fit with the given objective function measurement, and optimized the parameters of the Un SWF model, including the saturated-soil hydraulic conductivity, moisture content, matrix potential, and the Clapp and Hornberger constant. The optimal values of the model parameters were obtained during the DA period(the year 1986), and then the optimized parameters were used to improve the Un SWF model. Finally, numerical simulation experiments were carried out from 1986 to 1993 to evaluate the simulation capability of the improved model and to explore and realize the DA-based method for optimizing the soil water parameterization scheme in LSPMs. The experimental results indicated that the optimized model parameters improved and perfected the model based on the physical mechanism, and increased its simulation capability; the optimized model parameters had good temporal portability and their adaptability was stronger, achieving the aim of improving the model. Therefore, this method is reasonable and feasible. This paper provides a good reference for DA-based optimization of the parameterization schemes in LSPMs. 展开更多
关键词 data assimilation land surface process model parameterization scheme SCE-UA algorithm soft moisture
原文传递
Simultaneous estimation of soil moisture and hydraulic parameters using residual resampling particle filter 被引量:3
12
作者 BI HaiYun MA JianWen +1 位作者 QIN SiXian ZHANG HongJuan 《Science China Earth Sciences》 SCIE EI CAS 2014年第4期824-838,共15页
Land data assimilation(DA) has gradually developed into an important earth science research method because of its ability to combine model simulations and observations.Integrating new observations into a land surface ... Land data assimilation(DA) has gradually developed into an important earth science research method because of its ability to combine model simulations and observations.Integrating new observations into a land surface model by the DA method can correct the predicted trajectory of the model and thus,improve the accuracy of state variables.It can also reduce uncertainties in the model by estimating some model parameters simultaneously.Among the various DA methods,the particle filter is free from the constraints of linear models and Gaussian error distributions,and can be applicable to any nonlinear and non-Gaussian state-space model;therefore,its importance in land data assimilation research has increased.In this study,a DA scheme was developed based on the residual resampling particle filter.Microwave brightness temperatures were assimilated into the macro-scale semi-distributed variance infiltration capacity model to estimate the surface soil moisture and three hydraulic parameters simultaneously.Finally,to verify the scheme,a series of comparative experiments was performed with experimental data obtained during the Soil Moisture Experiment of 2004 in Arizona.The results show that the scheme can improve the accuracy of soil moisture estimations significantly.In addition,the three hydraulic parameters were also well estimated,demonstrating the effectiveness of the DA scheme. 展开更多
关键词 data assimilation residual resampling particle filter microwave brightness temperature soil moisture hydraulic parameter
原文传递
Incubation time approach in rock fracture dynamics 被引量:1
13
作者 SMIRNOV V PETROV Yuri V BRATOV V 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第1期78-85,共8页
The paper is summarizing latest results connected with application of the incubation time approach to problems of dynamic fracture of rock materials. Incubation time based fracture criteria for intact media and media ... The paper is summarizing latest results connected with application of the incubation time approach to problems of dynamic fracture of rock materials. Incubation time based fracture criteria for intact media and media with cracks are discussed. Available experimental data on high rate fracture of different rock materials and incubation time based fracture criteria are used in order to evaluate critical parameters of causing fracture in these materials. Previously discovered possibility to optimize (minimize) energy input for fracture is discussed in connection to industrial rock fracture processes. It is shown that optimal value of momentum associated with critical load in order to initialize fracture in rock media does strongly depend on the incubation time and the impact duration. Existence of optimal load shapes minimizing momentum for a single fracturing impact or a sequence of periodic fracturing impacts is demonstrated. 展开更多
关键词 incubation time dynamic fracture ROCKS dynamic strength fracture toughness crack resistance energy and momentum input fracture process optimization
原文传递
Source of the condensates from the Hetianhe Field and the genetic relationship between the condensates and their associated gases
14
作者 SONG DaoFu WANG TieGuan +1 位作者 LI MeiJun NI ZhiYong 《Science China Earth Sciences》 SCIE EI CAS CSCD 2015年第9期1566-1576,共11页
A detailed correlation of Hetianhe condensates versus typical source rocks from the Tarim Basin was established. Moreover, the genetic relationship between the condensates and their associated gases was also studied b... A detailed correlation of Hetianhe condensates versus typical source rocks from the Tarim Basin was established. Moreover, the genetic relationship between the condensates and their associated gases was also studied based on their geochemical com- positions and fluid inclusion data. Hetianhe condensates are characterized by high pristine/phytane (Pr/Ph) ratios, high relative abundances of Czs regular steranes, C26-C27 triaromatic steroids, and triaromatic dinosteranes, and relatively heavy stable car- bon isotopic compositions. They geochemically correlate well with the Cambrian source rocks, indicating that these conden- sates are derived from the Cambrian rocks. Based on several molecular maturity parameters, the condensates are recognized as being moderately to highly mature, which are too low in maturity to extensively crack into gases. The gases and condensates of the Hetianhe Field are derived from the same source rocks and the gases are from oil-cracking; however, clear evidence indi- cates that the gases were not cracked from their associated condensates and that the gas generation from oil-cracking did not occur in the present reservoirs. The liquid condensates produced from wellheads were likely dissolved in their associated gases underground and carried into the reservoirs by the gases. 展开更多
关键词 Hetianhe Field CONDENSATE MATURITY oil-source rock correlation genetic relationship
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部