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Application of entropy-based fuzzy matter-element analysis in seepage monitoring of RCC dam

Chongshi GU, Zhijun ZHANG, Xin CAI, Yue HOU

《结构与土木工程前沿(英文)》 2011年 第5卷 第1期   页码 105-111 doi: 10.1007/s11709-010-0015-4

摘要: Taking account of the fuzzy results of the seepage monitoring analysis of roller compacted concrete (RCC) dam and uncertainties of the individual indicator evaluation, the fuzzy matter-element model of seepage monitoring of RCC dam analysis has been established with the use of the fuzzy matter-element analysis theory and the concept of euclid approach degree. The use of entropy theory can calculate the weighting factor through the disorder utility values of the information reflected by the data itself, which can effectively avoid the problems of weight distribution and uncertainties of subjective judgments of the seepage monitoring analysis of roller compacted concrete dam. And further the example shows that the analysis of entropy-based fuzzy matter-element analysis model of the seepage monitoring of roller compacted concrete dam is in accordance with the actual situation, which verifies the effectiveness of the method.

关键词: information entropy     fuzzy matter-element     roller compacted concrete (RCC) dam     seepage analysis    

Principle of maximum entropy for reliability analysis in the design of machine components

Yimin ZHANG

《机械工程前沿(英文)》 2019年 第14卷 第1期   页码 21-32 doi: 10.1007/s11465-018-0512-z

摘要: We studied the reliability of machine components with parameters that follow an arbitrary statistical distribution using the principle of maximum entropy (PME). We used PME to select the statistical distribution that best fits the available information. We also established a probability density function (PDF) and a failure probability model for the parameters of mechanical components using the concept of entropy and the PME. We obtained the first four moments of the state function for reliability analysis and design. Furthermore, we attained an estimate of the PDF with the fewest human bias factors using the PME. This function was used to calculate the reliability of the machine components, including a connecting rod, a vehicle half-shaft, a front axle, a rear axle housing, and a leaf spring, which have parameters that typically follow a non-normal distribution. Simulations were conducted for comparison. This study provides a design methodology for the reliability of mechanical components for practical engineering projects.

关键词: machine components     reliability     arbitrary distribution parameter     principle of maximum entropy    

Entropy production analysis of swirling diffusion combustion processes

Deodat MAKHANLALL, Linhua LIU,

《能源前沿(英文)》 2010年 第4卷 第3期   页码 326-332 doi: 10.1007/s11708-009-0058-1

摘要: A critical factor in the design of combustion systems for optimum fuel economy and emission performance lies in adequately predicting thermodynamic irreversibilities associated with transport and chemical processes. The objective of this study is to map these irreversibilities in terms of entropy production for methane combustion. The numerical solution of the combustion process is conducted with the help of a Fluent 6.1.22 computer code, and the volumetric entropy production rate due to chemical reaction, viscous dissipation, and mass and heat transfer are calculated as post-processed quantities with the computed data of the reaction rates, fluid velocity, temperature and radiative intensity. This paper shows that radiative heat transfer, which is an important source of entropy production, cannot be omitted for combustion systems. The study is extended by conducting a parametric investigation to include the effects of wall emissivity, optical thickness, swirl number, and Boltzmann number on entropy production. Global entropy production rates decrease with the increase in swirl velocity, wall emissivity and optical thickness. Introducing swirling air into the combustion system and operations with the appropriate Boltzmann number reduces the irreversibility affected regions and improves energy utilization efficiency.

关键词: entropy-based design     radiation transfer     swirl     magnussen combustion-model    

Maximum entropy based finite element analysis of porous media

Emad NOROUZI, Hesam MOSLEMZADEH, Soheil MOHAMMADI

《结构与土木工程前沿(英文)》 2019年 第13卷 第2期   页码 364-379 doi: 10.1007/s11709-018-0470-x

摘要: The maximum entropy theory has been used in a wide variety of physical, mathematical and engineering applications in the past few years. However, its application in numerical methods, especially in developing new shape functions, has attracted much interest in recent years. These shape functions possess the potential for performing better than the conventional basis functions in problems with randomly generated coarse meshes. In this paper, the maximum entropy theory is adopted to spatially discretize the deformation variable of the governing coupled equations of porous media. This is in line with the well-known fact that higher-order shape functions can provide more stable solutions in porous problems. Some of the benchmark problems in deformable porous media are solved with the developed approach and the results are compared with available references.

关键词: maximum entropy FEM     fully coupled multi-phase system     porous media    

Optimization of cold-end system of thermal power plants based on entropy generation minimization

《能源前沿(英文)》 2022年 第16卷 第6期   页码 956-972 doi: 10.1007/s11708-021-0785-5

摘要: Cold-end systems are heat sinks of thermal power cycles, which have an essential effect on the overall performance of thermal power plants. To enhance the efficiency of thermal power plants, multi-pressure condensers have been applied in some large-capacity thermal power plants. However, little attention has been paid to the optimization of the cold-end system with multi-pressure condensers which have multiple parameters to be identified. Therefore, the design optimization methods of cold-end systems with single- and multi-pressure condensers are developed based on the entropy generation rate, and the genetic algorithm (GA) is used to optimize multiple parameters. Multiple parameters, including heat transfer area of multi-pressure condensers, steam distribution in condensers, and cooling water mass flow rate, are optimized while considering detailed entropy generation rate of the cold-end systems. The results show that the entropy generation rate of the multi-pressure cold-end system is less than that of the single-pressure cold-end system when the total condenser area is constant. Moreover, the economic performance can be improved with the adoption of the multi-pressure cold-end system. When compared with the single-pressure cold-end system, the excess revenues gained by using dual- and quadruple-pressure cold-end systems are 575 and 580 k$/a, respectively.

关键词: cold-end system     entropy generation minimization     optimization     economic analysis     genetic algorithm (GA)    

一类灰色模糊决策问题的熵权分析方法

罗党,刘思峰

《中国工程科学》 2004年 第6卷 第10期   页码 48-51

摘要:

以灰色系统理论和模糊数学为基础,探讨了不确定型决策问题的特性,分析了一些相关成果中所给方法在直接处理灰色模糊数方面的优势与不足。运用优化理论和熵极大化准则,建立了基于灰色模糊关系的多属性群体决策方法,分别对属性权重向量已知和未知两种情况给出了简便实用的算法,通过算例说明了算法的合理性。

关键词: 灰色模糊关系         多属性决策    

New method of fault diagnosis of rotating machinery based on distance of information entropy

Houjun SU, Tielin SHI, Fei CHEN, Shuhong HUANG

《机械工程前沿(英文)》 2011年 第6卷 第2期   页码 249-253 doi: 10.1007/s11465-011-0124-3

摘要:

This paper introduces the basic conception of information fusion and some fusion diagnosis methods commonly used nowadays in rotating machinery. From the thought of the information fusion, a new quantitative feature index monitoring and diagnosing the vibration fault of rotating machinery, which is called distance of information entropy, is put forward on the basis of the singular spectrum entropy in time domain, power spectrum entropy in frequency domain, wavelet energy spectrum entropy, and wavelet space feature entropy in time-frequency domain. The mathematic deduction suggests that the conception of distance of information entropy is accordant with the maximum subordination principle in the fuzzy theory. Through calculation it has been proved that this method can effectively distinguish different fault types. Then, the accuracy of rotor fault diagnosis can be improved through the curve chart of the distance of information entropy at multi-speed.

关键词: rotating machinery     information fusion     fault diagnosis     Information entropy     distance of the information entropy    

水处理系统网络攻击的检测和定位:基于熵的方法 Research Article

刘可1,汪慕峰2,麻荣宽1,张镇勇2,魏强1

《信息与电子工程前沿(英文)》 2022年 第23卷 第4期   页码 587-603 doi: 10.1631/FITEE.2000546

摘要: 随着工业4.0的发展,水处理系统作为一种典型工业信息物理系统逐渐接入互联网。先进的信息技术使水处理系统在可靠性、效率和经济性方面受益。然而,网络和基础设施中潜在的漏洞使水处理系统很容易遭受网络攻击。由于水处理系统对于实时性和可用性的严苛要求,传统的面向信息系统的防御机制无法直接应用于水处理系统。本文提出一种基于熵的入侵检测方法来抵御针对系统中控制器(如可编程逻辑控制器)的攻击。由于水处理系统运行条件的变化,在模型采用静态阈值进行检测时会产生较高误报率。因此本文提出一种动态阈值调整机制来提高所提方法的检测性能。为验证所提方法,我们建立了一个包含超过50个测量点的高保真水处理系统测试平台。在两种攻击场景下进行实验,共涵盖了36次攻击。结果表明,所提方法能够实现97.22%的检测率和1.67%的误报率。

关键词: 工业信息物理系统;水处理系统;入侵检测;异常状态;检测和定位;信息论    

High-order phase-field model with the local and second-order max-entropy approximants

Fatemeh AMIRI

《结构与土木工程前沿(英文)》 2019年 第13卷 第2期   页码 406-416 doi: 10.1007/s11709-018-0475-5

摘要: We approximate the fracture surface energy functional based on phase-field method with smooth local maximum entropy (LME) and second-order maximum entropy (SME) approximants. The higher-order continuity of the meshfree methods such as LME and SME approximants allows to directly solve the fourth-order phase-field equations without splitting the fourth-order differential equation into two second-order differential equations. We will first show that the crack surface functional can be captured more accurately in the fourth-order model with smooth approximants such as LME, SME and B-spline. Furthermore, smaller length scale parameter is needed for the fourth-order model to approximate the energy functional. We also study SME approximants and drive the formulations. The proposed meshfree fourth-order phase-field formulation show more stable results for SME compared to LME meshfree methods.

关键词: second-order maximum entropy     local maximum entropy     second- and fourth-order phase-field models     B-spline    

基于熵的不同工业生产模式环境影响比较研究

楚海林,李军

《中国工程科学》 2005年 第7卷 第10期   页码 43-45

摘要:

从热力学出发,分析了工业生产活动污染环境的熵本质,提出了度量工业生产活动的环境影响非平衡态熵流模型,并分别对三种不同生产模式的熵增值进行计算,得到三种不同生产模式的环境影响趋势,为可持续发展的生产模式的选择提供依据。

关键词: 熵增     环境影响     生产模式     可持续发展    

基于熵模型的大型建筑企业组织结构研究

王兴,詹伟,王国庆

《中国工程科学》 2014年 第16卷 第10期   页码 84-88

摘要:

分析了组织结构对企业管理的重要意义以及组织结构设计与信息传递的关系,基于国内外大型建筑企业组织结构的对比,发现国内外大型建筑企业组织结构的共性与差异。提出运用信息熵模型从时效和质量两个方面评价组织结构的有序度,为考查组织信息传递有效性提供了定量方法,据此对日本鹿岛建设集团和中国铁建股份有限公司进行了评价。

关键词: 组织结构     大型建筑企业     信息熵     有序度    

基于最大熵原理的复合形法及其在边坡稳定分析中的应用

李亮,迟世春,林皋

《中国工程科学》 2005年 第7卷 第4期   页码 64-68

摘要:

将最大熵原理应用于基本复合形法的优化计算中,旨在提高算法的寻优成功率。具体步骤为:选取复形中熵最大的顶点为寻优点;在复形其余各点的加权中心点与寻优点的连线上,搜索比寻优点改善的新顶点;并替换掉寻优点构成新的复形;如此迭代直至复形中的信息被完全利用。采用基本复合形法和基于最大熵原理的复合形法对两个复杂土坡的最小安全系数进行了搜索,结果表明基于最大熵原理的复合形法的全局搜索能力有了明显改善。

关键词:     复合形法     边坡稳定     安全系数    

High-entropy catalysts for electrochemical water-electrolysis of hydrogen evolution and oxygen evolution

《能源前沿(英文)》 doi: 10.1007/s11708-023-0892-6

摘要: High entropy materials (HEMs) have developed rapidly in the field of electrocatalytic water-electrolysis for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) due to their unique properties. In particular, HEM catalysts are composed of many elements. Therefore, they have rich active sites and enhanced entropy stability relative to single atoms. In this paper, the preparation strategies and applications of HEM catalysts in electrochemical water-electrolysis are reviewed to explore the stabilization of HEMs and their catalytic mechanisms as well as their application in support green hydrogen production. First, the concept and four characteristics of HEMs are introduced based on entropy and composition. Then, synthetic strategies of HEM catalysts are systematically reviewed in terms of the categories of bottom-up and top-down. The application of HEMs as catalysts for electrochemical water-electrolysis in recent years is emphatically discussed, and the mechanisms of improving the performance of electrocatalysis is expounded by combining theoretical calculation technology and ex-situ/in situ characterization experiments. Finally, the application prospect of HEMs is proposed to conquer the challenges in HEM catalyst fabrications and applications.

关键词: high-entropy     electrocatalysis     synthetic methods     water-electrolysis     hydrogen and oxygen evolutions    

Assembly design system based on engineering connection

Wensheng YIN

《机械工程前沿(英文)》 2016年 第11卷 第4期   页码 423-432 doi: 10.1007/s11465-016-0382-1

摘要:

An assembly design system is an important part of computer-aided design systems, which are important tools for realizing product concept design. The traditional assembly design system does not record the connection information of production on the engineering layer; consequently, the upstream design idea cannot be fully used in the downstream design. An assembly design model based on the relationship of engineering connection is presented. In this model, all nodes are divided into two categories: The component and the connection. Moreover, the product is constructed on the basis of the connection relationship of the components. The model is an And/Or graph and has the ability to record all assembly schemes. This model records only the connection information that has engineering application value in the product design. In addition, this model can significantly reduce the number of combinations, and is very favorable for the assembly sequence planning in the downstream. The system contains a connection knowledge system that can be mapped to the connection node, and the connection knowledge obtained in practice can be returned to the knowledge system. Finally, VC++6.0 is used to develop a prototype system called Connect-based Assembly Planning (CAP). The relationship between the CAP system and the commercial assembly design system is also established.

关键词: product design     assembly design     engineering connection     assembly sequence planning    

Urban design based on public safety-Discussion on safety-based urban design

Kaizhen CAI, Jianguo WANG

《结构与土木工程前沿(英文)》 2009年 第3卷 第2期   页码 219-227 doi: 10.1007/s11709-009-0023-4

摘要: Because of public safety problems in construction of urban surroundings, this paper expounds the necessity of the study on public safety-based urban design in perspective of modern city. It brings forward the concept of safety-based urban design and attempts to explore the basic connotation and contents with framework for studies.

关键词: urban public safety     urban design     safety-based urban design    

标题 作者 时间 类型 操作

Application of entropy-based fuzzy matter-element analysis in seepage monitoring of RCC dam

Chongshi GU, Zhijun ZHANG, Xin CAI, Yue HOU

期刊论文

Principle of maximum entropy for reliability analysis in the design of machine components

Yimin ZHANG

期刊论文

Entropy production analysis of swirling diffusion combustion processes

Deodat MAKHANLALL, Linhua LIU,

期刊论文

Maximum entropy based finite element analysis of porous media

Emad NOROUZI, Hesam MOSLEMZADEH, Soheil MOHAMMADI

期刊论文

Optimization of cold-end system of thermal power plants based on entropy generation minimization

期刊论文

一类灰色模糊决策问题的熵权分析方法

罗党,刘思峰

期刊论文

New method of fault diagnosis of rotating machinery based on distance of information entropy

Houjun SU, Tielin SHI, Fei CHEN, Shuhong HUANG

期刊论文

水处理系统网络攻击的检测和定位:基于熵的方法

刘可1,汪慕峰2,麻荣宽1,张镇勇2,魏强1

期刊论文

High-order phase-field model with the local and second-order max-entropy approximants

Fatemeh AMIRI

期刊论文

基于熵的不同工业生产模式环境影响比较研究

楚海林,李军

期刊论文

基于熵模型的大型建筑企业组织结构研究

王兴,詹伟,王国庆

期刊论文

基于最大熵原理的复合形法及其在边坡稳定分析中的应用

李亮,迟世春,林皋

期刊论文

High-entropy catalysts for electrochemical water-electrolysis of hydrogen evolution and oxygen evolution

期刊论文

Assembly design system based on engineering connection

Wensheng YIN

期刊论文

Urban design based on public safety-Discussion on safety-based urban design

Kaizhen CAI, Jianguo WANG

期刊论文