期刊文献+
共找到311篇文章
< 1 2 16 >
每页显示 20 50 100
Computational algorithms for simulating the grain structure formed on steel billets using cellular automaton and chaos theories 被引量:2
1
作者 A.Ramírez-López G.Soto-Cortés +1 位作者 J.González-Trejo D.Muoz-Negrón 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2011年第1期24-34,共11页
The development of some computational algorithms based on cellular automaton was described to simulate the structures formed during the solidification of steel products.The algorithms described take results from the s... The development of some computational algorithms based on cellular automaton was described to simulate the structures formed during the solidification of steel products.The algorithms described take results from the steel thermal behavior and heat removal previously calculated using a simulator developed by present authors in a previous work.Stored time is used for displaying the steel transition from liquid to mushy and solid.And it is also used to command computational subroutines that reproduce nucleation and grain growth.These routines are logically programmed using the programming language C++ and are based on a simultaneous solution of numerical methods (stochastic and deterministic) to create a graphical representation of different grain structures formed.The grain structure obtained is displayed on the computer screen using a graphical user interface (GUI).The chaos theory and random generation numbers are included in the algorithms to simulate the heterogeneity of grain sizes and morphologies. 展开更多
关键词 continuous casting SOLIDIFICATION grain growth algorithms computer simulation
在线阅读 下载PDF
An Algorithm to Analyze Electron Backscatter Diffraction Data for Grain Reconstruction:from Methodology to Application
2
作者 Xue-Hao Zheng Hong-Wang Zhang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2016年第5期491-499,共9页
An algorithm for grain reconstruction based on electron backscatter diffraction data was proposed in this paper. This algorithm can well record the original data arrangement when an external file for the reconstructed... An algorithm for grain reconstruction based on electron backscatter diffraction data was proposed in this paper. This algorithm can well record the original data arrangement when an external file for the reconstructed grain(s) was exported for further post-processing. Assisted by an in-house MATLAB program, grain reconstruction, lattice rotations, orientation spreads, and slip system analysis can be performed. The validity of this algorithm has been successfully tested by polycrystalline Ni before and after channel die compression. 展开更多
关键词 grain reconstruction algorithm Electron backscatter diffraction DEFORMATION Nickle
原文传递
Algorithm for repairing the damaged images of grain structures obtained from the cellular automata and measurement of grain size 被引量:1
3
作者 A.Ramírez-López M.A.Romero-Romo +3 位作者 D.Muñoz-Negron S.López-Ramírez R.Escarela-Pérez C.Duran-Valencia 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2012年第10期899-907,共9页
Computational models are developed to create grain structures using mathematical algorithms based on the chaos theory such as cellular automaton, geometrical models, fractals, and stochastic methods. Because of the ch... Computational models are developed to create grain structures using mathematical algorithms based on the chaos theory such as cellular automaton, geometrical models, fractals, and stochastic methods. Because of the chaotic nature of grain structures, some of the most popular routines are based on the Monte Carlo method, statistical distributions, and random walk methods, which can be easily programmed and included in nested loops. Nevertheless, grain structures are not well defined as the results of computational errors and numerical incon- sistencies on mathematical methods. Due to the finite definition of numbers or the numerical restrictions during the simulation of solidifica- tion, damaged images appear on the screen. These images must be repaired to obtain a good measurement of grain geometrical properties. Some mathematical algorithms were developed to repair, measure, and characterize grain structures obtained from cellular automata in the present work. An appropriate measurement of grain size and the corrected identification of interfaces and length are very important topics in materials science because they are the representation and validation of mathematical models with real samples. As a result, the developed al- gorithms are tested and proved to be appropriate and efficient to eliminate the errors and characterize the grain structures. 展开更多
关键词 grain size and shape image restoration mathematical algorithms cellular automata SOLIDIFICATION
在线阅读 下载PDF
Optimization Algorithm in the Simulation of Ceramic Grain Growth
4
作者 ZENG Zhong-chen 1, JI Guo-li 1, XIONG Zhao-xian 2, LIU Zong-xi 1 (1. Department of Automation, Xiamen University, 2. Department of Materials Science and Engineering, Xiamen University, Xiamen 361005, China) 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期292-,共1页
Optimization Algorithm was developed for the simula ti on of ceramic grain growth at atomistic scale. Based on the coordination informa tion of different atoms, a structure of trident tree was applied to save large q ... Optimization Algorithm was developed for the simula ti on of ceramic grain growth at atomistic scale. Based on the coordination informa tion of different atoms, a structure of trident tree was applied to save large q uantities data, so as to solve the problems of large data information and long r unning time. For every atom a binary tree was firstly formed according to the X coordination of atom. If the values of X coordination were the same, the middle sub-tree of first layer formed then a binary tree according to the Y coordinati on of atom. If the values of Y coordination were also the same, the middle sub- tree of second layer formed then a binary tree according to the Z coordination o f atom. In this way the speed of whole program is enhanced obviously. In order t o reduce memory, in this structure only need to store the exterior atoms’ infor mation, an integer is used to store the interior atoms’ information. If other a toms take up an atom’s all adjacent positions, this atom will be deleted in the data structure, for all the adjacent positions’ atoms, the integer’s relative bit will be set 1 to denote that there is an atom in this position but not be s tored in the trident tree. When an outside atom is deleted, for all the bits tha t are set 1,an atom will be added to the trident tree as an outside atom for the relative positions. And for this new added atom, the integer’s relative bi t of all the adjacent position’s atoms should be set 0 to denote that there is no interior atom in this position. In this way, if there are n 3 atoms, onl y need to store 6n 2 quantity’s atoms’ information. Large quantity of mem ory space can then be saved. 展开更多
关键词 optimization algorithm computer simulation cera mic grain growth
在线阅读 下载PDF
Application of Hooke &Jeeves Algorithm in Optimizing Fusion Zone Grain Size and Hardness of Pulsed Current Micro Plasma Arc Welded AISI 304L Sheets
5
作者 Kondapalli Siva Prasad Chalamalasetti Srinivasa Rao Damera Nageswara Rao 《Journal of Minerals and Materials Characterization and Engineering》 2012年第9期869-875,共7页
AISI 304L is an austenitic Chromium-Nickel stainless steel offering the optimum combination of corrosion resistance, strength and ductility. These attributes make it a favorite for many mechanical components. The pape... AISI 304L is an austenitic Chromium-Nickel stainless steel offering the optimum combination of corrosion resistance, strength and ductility. These attributes make it a favorite for many mechanical components. The paper focuses on developing mathematical models to predict grain size and hardness of pulsed current micro plasma arc welded AISI 304L joints. Four factors, five level, central composite rotatable design matrix is used to optimize the number of experiments. The mathematical models have been developed by Response Surface Method (RSM) and its adequacy is checked by Analysis of Variance (ANOVA) technique. By using the developed mathematical models, grain size and hardness of the weld joints can be predicted with 99% confidence level. The developed mathematical models have been optimized using Hooke and Jeeves algorithm to minimize grain size and maximize the hardness. 展开更多
关键词 Pulsed Current MICRO Plasma Arc Welding AISI 304L grain Size HARDNESS Hooke & Jeeves algorithm
暂未订购
Grain型级联反馈移存器的非奇异性判定 被引量:2
6
作者 王秋艳 金晨辉 《计算机工程》 CAS CSCD 2014年第3期167-170,174,共5页
Grain算法是欧洲序列密码工程eSTREAM最终入选的面向硬件实现的3个序列密码算法之一,它由2个反馈移存器和前馈函数组成,能有效抵御基于线性反馈移存器的序列密码攻击。针对以Grain算法为特例的Grain型级联反馈移存器的非奇异性判定问题... Grain算法是欧洲序列密码工程eSTREAM最终入选的面向硬件实现的3个序列密码算法之一,它由2个反馈移存器和前馈函数组成,能有效抵御基于线性反馈移存器的序列密码攻击。针对以Grain算法为特例的Grain型级联反馈移存器的非奇异性判定问题,给出Grain型级联反馈移存器在初始化过程和密钥流生成过程中,状态刷新变换均构成双射的充分条件,并通过反例说明对于有限域上的Grain型级联反馈移存器,即使所使用的2个移存器都是非奇异的,并且前馈函数满足相应性质,其状态刷新变换仍可能不构成双射。利用Grain v1算法验证了该非奇异性判定结果的正确性。 展开更多
关键词 序列密码 grain算法 非线性反馈移存器 非奇异性 状态刷新变换 双射性
在线阅读 下载PDF
Multidisciplinary Design and Optimization of Multistage Ground-launched Boost Phase Interceptor Using Hybrid Search Algorithm 被引量:9
7
作者 Qasim Zeeshan Khurram Nisar +1 位作者 Ali Kamran Amer Rafique 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2010年第2期170-178,共9页
This article proposes a multidisciplinary design and optimization (MDO) strategy for the conceptual design of a multistage ground-based interceptor (GBI) using hybrid optimization algorithm, which associates genet... This article proposes a multidisciplinary design and optimization (MDO) strategy for the conceptual design of a multistage ground-based interceptor (GBI) using hybrid optimization algorithm, which associates genetic algorithm (GA) as a global optimizer with sequential quadratic programming (SQP) as a local optimizer. The interceptor is comprised of a three-stage solid propulsion system for an exoatmospheric boost phase intercept (BPI). The interceptor's duty is to deliver a kinetic kill vehicle (KKV) to the optimal position in space to accomplish the mission of intercept. The modules for propulsion, aerodynamics, mass properties and flight dynamics are integrated to produce a high fidelity model of the entire vehicle. The propulsion module com- prises of solid rocket motor (SRM) grain design, nozzle geometry design and performance prediction analysis. Internal ballistics and performance prediction parameters are calculated by using lumped parameter method. The design objective is to minimize the gross lift off mass (GLOM) of the interceptor under the mission constraints and performance objectives. The proposed design and optimization methodology provide designers with an efficient and powerful approach in computation during designing interceptor systems. 展开更多
关键词 boost phase genetic algorithm grain design INTERCEPTOR OPTIMIZATION solid rocket motor
原文传递
基于Grain v1的认证加密算法研究与设计 被引量:1
8
作者 林紫欣 鲁小娟 张艳硕 《北京电子科技学院学报》 2024年第1期23-39,共17页
Grain v1算法为eSTREAM项目面向硬件的优胜算法之一,在硬件实现方面极具优势。本文针对Grain v1的结构弱点对其进行细节修改,并在此基础上提出Grain v1+AE和Grain v1+AEAD两种认证加密算法。这两种算法在保证机密性和完整性的同时,为Gr... Grain v1算法为eSTREAM项目面向硬件的优胜算法之一,在硬件实现方面极具优势。本文针对Grain v1的结构弱点对其进行细节修改,并在此基础上提出Grain v1+AE和Grain v1+AEAD两种认证加密算法。这两种算法在保证机密性和完整性的同时,为Grain系列认证加密算法在安全等级、硬件规模角度提供更多选择,拓展Grain系列算法适用范围。 展开更多
关键词 grain v1 认证加密算法 AEAD 密码分析 安全性 面向硬件设计
在线阅读 下载PDF
Grain-128算法的密码体制识别研究 被引量:3
9
作者 赵志诚 赵亚群 刘凤梅 《信息工程大学学报》 2019年第1期102-110,共9页
密码体制识别是进一步开展密码分析的基础,也是区分攻击的一个重要方面。对Grain-128密码体制的识别进行研究,首先提取多种密文特征,随后基于随机森林算法构建密码体制识别分类器,对Grain-128与其他11种密码体制进行两两识别。实验结果... 密码体制识别是进一步开展密码分析的基础,也是区分攻击的一个重要方面。对Grain-128密码体制的识别进行研究,首先提取多种密文特征,随后基于随机森林算法构建密码体制识别分类器,对Grain-128与其他11种密码体制进行两两识别。实验结果表明,基于随机性测试的密文特征识别性能优于现有的密文特征,其平均识别准确率最高可达到81%,与现有密文特征相比,识别准确率提高10%以上。t-SNE算法在保持识别准确率前提下,降低了部分特征的维数,提高了数据效用。 展开更多
关键词 密码体制识别 grain-128算法 随机森林算法 随机性测试 t-SNE算法
在线阅读 下载PDF
基于智能算法的储粮通风温度预测 被引量:1
10
作者 吕宗旺 柳航 孙福艳 《中国农机化学报》 北大核心 2025年第1期91-98,共8页
在当前粮食安全日益受到关注的背景下,对储粮过程中的温度波动进行准确预测,并通过智能化的通风控制系统实现对储粮环境的优化管理成为亟待解决的问题。基于此,提出一种CNN-BiGRU-Attention网络模型,通过CNN提取特征图中时序数据之间的... 在当前粮食安全日益受到关注的背景下,对储粮过程中的温度波动进行准确预测,并通过智能化的通风控制系统实现对储粮环境的优化管理成为亟待解决的问题。基于此,提出一种CNN-BiGRU-Attention网络模型,通过CNN提取特征图中时序数据之间的潜在关系,并将处理后的特征向量作为BiGRU网络的输入,根据粮情数据的时序特征,在BiGRU网络中加入Attention为粮情特征分配权重;以及采用IPSO优化模型超参数的多模型融合算法来预测粮堆温度。使用吉林省榆树某直属粮库的数据集验证该预测模型,结果显示:均方根误差RMSE为0.046 9,平均绝对误差MAE为0.031 5,确定系数R~2为0.992 5,与其他模型相比,有效地提高预测精度。通过将储粮温度预测功能应用于粮情测控系统中,实现机械通风智能化来保障粮食的安全储藏。 展开更多
关键词 储粮温度预测 改进粒子群算法 粮食储藏 通风控制
在线阅读 下载PDF
Research on Location-Inventory Model in Grain Emergency Network
11
作者 Lin Wang Wenzhuo Liang Yunxian Hou 《Journal of Computer and Communications》 2014年第14期52-58,共7页
Once the disaster occurred, a huge amount of grain supply is needed from disaster area. Because of the short shelf life, grain is very strict with reserve environment and needed to rotate on a regular basis in the pro... Once the disaster occurred, a huge amount of grain supply is needed from disaster area. Because of the short shelf life, grain is very strict with reserve environment and needed to rotate on a regular basis in the process of reserves. Considering the limitations of existing related research, this paper presented a facility location model for grain emergency network that incorporates inventory factors and rotation mechanism, and then designed genetic algorithm based on Matlab to solve the model. Finally we verified the feasibility and effectiveness of the algorithm by computational examples and presented the directions for future work. 展开更多
关键词 Location-Inventory grain EMERGENCY NETWORK GENETIC algorithm
暂未订购
Review of snow grain size retrieval from remote sensing
12
作者 ZhongMing Guo HongBo Wu +2 位作者 RuiJuan Mao ChunWen Zhang YuWei Wu 《Research in Cold and Arid Regions》 CSCD 2013年第2期251-258,共8页
In this paper, the significance and history of studying snow grain size is introduced. Based on the assumption that high reflectivity in the visible band and significant decreasing reflectivity of snow surface in the ... In this paper, the significance and history of studying snow grain size is introduced. Based on the assumption that high reflectivity in the visible band and significant decreasing reflectivity of snow surface in the infrared band, the grain size of snow, spherical and non-spherical, is sensitive to changes in remote sensing retrieval foundation. Also, models and algorithms applied in current studies are reviewed, together with their advantages and disadvantages. In addition, in order to obtain retrieval accuracy, some factors that may affect grain size are also discussed, such as temperature, wavelength, arid particle shape, as well as method authentication. 展开更多
关键词 snow grain size remote sensing retrieval MODEL algorithm
在线阅读 下载PDF
A cellular automata model for simulating grain structures with straight and hyperbolic interfaces
13
作者 A.Ramírez-López M.Palomar-Pardavé +3 位作者 D.Muñoz-Negrón C.Duran-Valencia S.López-Ramirez G.Soto-Cortés 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2012年第8期699-710,共12页
A description of a mathematical algorithm for simulating grain structures with straight and hyperbolic interfaces is shown. The presence of straight and hyperbolic interfaces in many grain structures of metallic mater... A description of a mathematical algorithm for simulating grain structures with straight and hyperbolic interfaces is shown. The presence of straight and hyperbolic interfaces in many grain structures of metallic materials is due to different solidification conditions, in- eluding different solidification speeds, growth directions, and delaying on the nucleation times of each nucleated node. Grain growth is a complex problem to be simulated; therefore, computational methods based on the chaos theory have been developed for this purpose. Straight and hyperbolic interfaces are between columnar and equiaxed grain structures or in transition zones. The algorithm developed in this work involves random distributions of temperature to assign preferential probabilities to each node of the simulated sample for nucleation according to previously defined boundary conditions. Moreover, more than one single nucleation process can be established in order to gen- erate hyperbolic interfaces between the grains. The appearance of new nucleated nodes is declared in sequences with a particular number of nucleated nodes and a number of steps for execution. This input information influences directly on the final grain structure (grain size and dislribution). Preferential growth directions are also established to obtain equiaxed and columnar grains. The simulation is done using rou- tines for nucleation and growth nested inside the main function. Here, random numbers are generated to place the coordinates of each new nucleated node at each nucleation sequence according to a solidification probability. Nucleation and growth routines are executed as a func- tion of nodal availability in order to know if a node will be part of a grain. Finally, this information is saved in a two-dimensional computa- tional array and displayed on the computer screen placing color pixels on the corresponding position forming an image as is done in cellular automaton. 展开更多
关键词 grain growth INTERFACES grain size and shape computational methods algorithmS cellular automata computer simulation
在线阅读 下载PDF
A NEURAL NETWORK-BASED MODEL FOR PREDICTION OF HOT-ROLLED AUSTENITE GRAIN SIZE AND FLOW STRESS IN MICROALLOY STEEL
14
作者 J. T.Niu,L.J.Sun and P.Karjalainen 1) Harbin Institute of Technology, Harbin 150001, China 2) University of Oulu, FIN-90571, Oulu, Finland 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2000年第2期521-530,共10页
For the great significance of the prediction of control parameters selected for hot-rolling and the evaluation of hot-rolling quality for the analysis of prod uction problems and production management, the selection o... For the great significance of the prediction of control parameters selected for hot-rolling and the evaluation of hot-rolling quality for the analysis of prod uction problems and production management, the selection of hot-rolling control parameters was studied for microalloy steel by following the neural network principle. An experimental scheme was first worked out for acquisition of sample data, in which a gleeble-1500 thermal simolator was used to obtain rolling temperature, strain, stain rate, and stress-strain curves. And consequently the aust enite grain sizes was obtained through microscopic observation. The experimental data was then processed through regression. By using the training network of BP algorithm, the mapping relationship between the hotrooling control parameters (rolling temperature, stain, and strain rate) and the microstructural paramete rs (austenite grain in size and flow stress) of microalloy steel was function appro ached for the establishment of a neural network-based model of the austeuite grain size and flow stress of microalloy steel. From the results of estimation made with the neural network based model, the hot-rolling control parameters can be effectively predicted. 展开更多
关键词 microalloy steel controlled rolling austenite grain size flow stress neural network BP algorithm
在线阅读 下载PDF
基于近红外光谱的灌浆期玉米籽粒水分定量分析通用模型 被引量:2
15
作者 王雪 张广月 +3 位作者 马铁民 赵肖宇 刘金明 衣淑娟 《农业工程学报》 北大核心 2025年第8期291-300,共10页
玉米育种过程中,灌浆期籽粒含水率检测时,通常需要脱粒,采集穗中间200粒为检测样本。为了保护亲本,避免破坏性检测,该研究提出一种基于近红外光谱的灌浆期玉米籽粒水分定量分析通用模型,用于灌浆期玉米籽粒水分的田间原位检测。首先构建... 玉米育种过程中,灌浆期籽粒含水率检测时,通常需要脱粒,采集穗中间200粒为检测样本。为了保护亲本,避免破坏性检测,该研究提出一种基于近红外光谱的灌浆期玉米籽粒水分定量分析通用模型,用于灌浆期玉米籽粒水分的田间原位检测。首先构建GA-IRIV-DS光谱数据处理策略。利用遗传算法(genetic algorithm,GA)和迭代保留信息变量(iterative retention of information variables,IRIV)二次波长筛选方法,提取光谱数据中有效的水分变量信息,减小特征空间维度的同时提高模型预测精度;再结合直接校正算法(direct standardization,DS),降低预测样本与建模样本的差异性,将玉米灌浆期穗尖部籽粒光谱数据校正为中间200籽粒的光谱,使水分定量分析模型能够具备中间200籽粒和穗尖部籽粒2种检测样本的通用性。在GA-IRIV-DS光谱数据处理策略的基础上,构建基于偏最小二乘法(partial lpeast squares regression,PLSR)的水分定量分析通用模型。经过验证,GA-IRIV-DS光谱数据处理策略校正后的光谱差异性降低了59.4%。为了进一步验证GA-IRIV-DS光谱数据处理策略的有效性,分析了GA+IRIVN组合波长筛选提取光谱特征,并分别与全光谱、多种典型波长筛选方法结合DS方法构建基于偏最小二乘法(PLSR)的水分定量分析模型结果相比较。试验结果表明,两种样本预测集GA-IRIVN-DS-PLSR模型效果均优于全光谱和其他模型,中间籽粒样本和穗尖部籽粒样本的预测决定系数(R^(2))达到了0.9715和0.9012,均方根误差(RMSEP)较全光谱下降了80.10%和64.60%。证明基于GA-IRIVN-DS光谱数据处理策略建立的近红外光谱水分定量分析模型具有一定泛化能力,可以为玉米育种过程中,减少检测过程中的样本破坏和提高检测效率提供可行的参考方法。 展开更多
关键词 近红外光谱 遗传算法 迭代保留信息变量 玉米籽粒水分 定量分析
在线阅读 下载PDF
粮食生产大数据平台研究进展与展望 被引量:2
16
作者 杨贵军 赵春江 +13 位作者 杨小冬 杨浩 胡海棠 龙慧灵 裘正军 李娴 江冲亚 孙亮 陈雷 周清波 郝星耀 郭威 王培 高美玲 《智慧农业(中英文)》 2025年第2期1-12,共12页
[目的/意义]农业大数据爆炸式发展,加速农业生产迈入数字化、智能化新时代。作为新质生产力,大数据服务于粮食生产全过程综合智能化管理决策,面临粮食生产大数据资源治理机制不明、全链条化粮食生产决策核心算法体系缺乏且对外依存度高... [目的/意义]农业大数据爆炸式发展,加速农业生产迈入数字化、智能化新时代。作为新质生产力,大数据服务于粮食生产全过程综合智能化管理决策,面临粮食生产大数据资源治理机制不明、全链条化粮食生产决策核心算法体系缺乏且对外依存度高、粮食生产全过程全要素的大数据平台缺乏等问题。[进展]本文综合分析了国内外粮食生产大数据、农情监测与智能决策算法、大数据平台方面的相关进展和面临的挑战,面向产前规划、产中监测与决策、产后综合评价等粮食生产全程管理决策需求,构建由多源异构粮食生产大数据治理、粮食生产知识图谱、“数据获取-信息提取-知识构建-智能决策-农机作业”全链条标准化算法体系、数字孪生典型应用场景等环节组成的粮食生产大数据智能平台。[结论/展望]应重点关注宏观管理监测和微观农场全程智能化生产作业需求,聚焦粮食生产典型应用场景,充分融合大数据与人工智能、数字孪生及云边端等新技术,探索技术联通集成为本,智能化服务为魂的大数据平台研发路径,创建开放式作物与环境传感接入、核心算法成熟度分级与云原生封装、高效数据与决策服务响应等为核心特色的开放共生型粮食生产大数据平台,实现数据-算法-服务全链条智能化、决策信息与智能装备作业一体化、粮食生产大数据平台与应用体系标准化,形成保障粮食安全高效绿色生产的新质生产力。 展开更多
关键词 粮食生产 大数据平台 农情监测 智能算法 决策支持 新质生产力
在线阅读 下载PDF
考虑损耗的粮食装载方式与运输路径联合优化
17
作者 万民 匡海波 +4 位作者 贾鹏 余方平 马千里 张益阁 赵素娥 《交通运输系统工程与信息》 北大核心 2025年第1期15-23,共9页
高质量的粮食流通体系是保障粮食供需平衡和粮食安全的重要保障。本文考虑粮食货种易损耗特性,以运输、碳排放、损耗总成本最小化为目标,构建同时考虑“袋装-散装-集装箱装载”不同装载方式和“公路-铁路-水路”不同运输方式的联合优化... 高质量的粮食流通体系是保障粮食供需平衡和粮食安全的重要保障。本文考虑粮食货种易损耗特性,以运输、碳排放、损耗总成本最小化为目标,构建同时考虑“袋装-散装-集装箱装载”不同装载方式和“公路-铁路-水路”不同运输方式的联合优化模型,并以我国东北地区“北粮南运”为现实场景,采用启发式遗传算法开展算例分析。计算结果表明:粮食集装箱公铁水多式联运相比包粮和散粮运输具有明显的低总成本和低损耗优势,损耗成本占比分别为9.86%、42.29%、29.82%。“北粮南运”过程中公路定位于两端集疏运,铁路和水路承担干线长距离运输,随着运达时长要求的提高,铁路占比逐渐增加,水路占比逐渐减少,当运达总时长为71.5 h,最优运输方案由集装箱公铁水联运转变为集装箱公铁联运。在总成本构成中,3种装载方式最优路径的运输成本、碳排成本基本相同,政府管理部门、物流服务提供商应认识到降低粮食运输损耗量是降低全程物流运输成本的有效方式。 展开更多
关键词 综合运输 路径优化 遗传算法 粮食运输 装载方式 粮食损耗
在线阅读 下载PDF
复杂碎屑岩粒度测井反演方法及在岩性精细识别中的应用 被引量:4
18
作者 任昱霏 闫建平 +2 位作者 王敏 宋东江 耿斌 《古地理学报》 北大核心 2025年第1期240-255,共16页
南海西部Y盆地L地区中新统地层呈高温、超高压特征,钻井难度大、取心资料少,岩屑录井反映岩性的精度较低,难以满足岩性精细识别的要求。以Y盆地L地区黄流组二段深层复杂碎屑岩为例,首先,利用有限的壁心粒度分析、录井、测井等资料,优选... 南海西部Y盆地L地区中新统地层呈高温、超高压特征,钻井难度大、取心资料少,岩屑录井反映岩性的精度较低,难以满足岩性精细识别的要求。以Y盆地L地区黄流组二段深层复杂碎屑岩为例,首先,利用有限的壁心粒度分析、录井、测井等资料,优选出表征岩性的粒度参数:粒度中值Md和对粒度变化敏感的自然伽马、密度、中子、声波时差、电阻率5条测井曲线,构建粒度中值Md-测井5变量数据集;其次,采用K-MEANS聚类方法,将数据集根据“误差平方和与聚类数”最优关系划分成了4类(简称“粒度分类”),分类后优化了粒度中值Md与测井响应的相关性,且获得不同类别的测井响应特征和相应岩性类型;然后,在实际井资料处理过程中,应用Fisher判别方程来判别未知深度点所属的粒度分类类型;最后,建立粒度分类下基于XGBoost算法的粒度中值测井智能计算模型,依据不同岩性对应粒度中值的数值范围,实现了井筒剖面上根据测井反演粒度中值Md曲线进而达到岩性精细识别的目的。研究结果表明:L地区黄流组二段考虑粒径的差异将砂岩岩性划分为:粉砂岩、细砂岩、中砂岩、粗砂岩,其中细砂岩和中砂岩是最主体发育的岩性,粒度中值Md与不同粒径岩性的关系最密切,是最能反映不同粒径岩性的粒度参数;粒度分类后基于XGBoost算法的粒度中值测井智能计算模型预测效果优于多元回归预测模型,计算粒度中值与实测值的相关系数达0.9397,平均绝对误差MAE为0.0195 mm,平均相对误差MRE为17.52%。该模型是一种有效实现深层复杂碎屑岩岩性精细识别的方法,也为纵向剖面上沉积粒序分析和储层构型精细解释、有效性评价奠定了基础。 展开更多
关键词 南海 中新统 复杂岩性 粒度中值 测井 反演 机器学习 XGBoost算法
在线阅读 下载PDF
基于Stacking集成算法的中国南方地区粮食产量预测
19
作者 马滇璟 赵家松 +3 位作者 严伟榆 段光俊 刘振洋 吴绍天 《湖北农业科学》 2025年第5期155-159,184,共6页
基于中国南方地区1998—2022年安徽省、湖北省、湖南省、江苏省和四川省的粮食产量及11个维度的相关因素数据,构建基于Stacking集成算法的BP-SVR-Stacking粮食产量预测模型,并将其与BP神经网络模型和SVR模型进行对比分析。结果表明,BP-S... 基于中国南方地区1998—2022年安徽省、湖北省、湖南省、江苏省和四川省的粮食产量及11个维度的相关因素数据,构建基于Stacking集成算法的BP-SVR-Stacking粮食产量预测模型,并将其与BP神经网络模型和SVR模型进行对比分析。结果表明,BP-SVR-Stacking模型的平均绝对误差(MAE)和平均绝对百分比误差(MAPE)均低于BP神经网络模型和SVR模型,说明BP-SVR-Stacking模型的预测能力优于单一的机器学习模型。相较于BP神经网络模型和SVR模型,BP-SVR-Stacking模型的决定系数(R^(2))分别提高了0.124和0.122,说明BP-SVR-Stacking模型具有良好的拟合能力和预测性能。 展开更多
关键词 Stacking集成算法 粮食产量 中国南方 预测
在线阅读 下载PDF
清蒸高粱糊化度检测及其蒸粮效果评价方法研究 被引量:1
20
作者 李晨阳 杨平 +5 位作者 秦辉 杨峰 蔡小波 曾智娟 冉弋凡 董亮 《食品与发酵工业》 北大核心 2025年第17期150-158,共9页
基于近红外偏最小二乘法(near-infrared partial least squares,NIR-PLS)开发了一种近红外光谱快速检测模型,用于快速、无损检测清蒸高粱糊化度。同时分析了白酒酿造生产关键指标相关性,以清蒸高粱糊化度为基础,结合清蒸高粱感官评价、... 基于近红外偏最小二乘法(near-infrared partial least squares,NIR-PLS)开发了一种近红外光谱快速检测模型,用于快速、无损检测清蒸高粱糊化度。同时分析了白酒酿造生产关键指标相关性,以清蒸高粱糊化度为基础,结合清蒸高粱感官评价、出入窖糟醅理化、出酒率、基础酒理化及评分,利用自适应权重算法(adaptive weights,AW)建立了一种清蒸高粱蒸粮效果评价方法。该检测模型在预测清蒸高粱糊化度方面具有较高的相关性,模型预测值与建模参考值之间的决定系数R^(2)=0.9771。此外,蒸粮效果评价方法验证结果与经验丰富的酿酒师的感官评定相吻合。当75≤糊化度检测值≤80时,清蒸高粱糊化效果评价为优级;65≤糊化度检测值<75时,评价为一级;55<糊化度检测值<65或80<糊化度检测值<90时,评价为二级;糊化度检测值≥90或糊化度检测值≤55时,评价为不合格。该评价方法量化了白酒生产中清蒸高粱蒸粮效果的评定,将依赖经验的感官评估方式转化为标准化、数字化的手段,有助于加强生产过程和产品质量的可控性,减少粮食损耗。 展开更多
关键词 近红外光谱 快速检测模型 自适应权重算法 清蒸高粱蒸粮效果 评价方法
在线阅读 下载PDF
上一页 1 2 16 下一页 到第
使用帮助 返回顶部