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期刊论文 61

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S-N曲线 2

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Multi-objective optimization of molten carbonate fuel cell system for reducing CO

Ramin ROSHANDEL,Majid ASTANEH,Farzin GOLZAR

《能源前沿(英文)》 2015年 第9卷 第1期   页码 106-114 doi: 10.1007/s11708-014-0341-7

摘要: The aim of this paper is to investigate the implementation of a molten carbonate fuel cell (MCFC) as a CO separator. By applying multi-objective optimization (MOO) using the genetic algorithm, the optimal values of operating load and the corresponding values of objective functions are obtained. Objective functions are minimization of the cost of electricity (COE) and minimization of CO emission rate. CO tax that is accounted as the pollution-related cost, transforming the environmental objective to the cost function. The results show that the MCFC stack which is fed by the syngas and gas turbine exhaust, not only reduces CO emission rate, but also produces electricity and reduces environmental cost of the system.

关键词: molten carbonate fuel cell (MCFC)     multi-objective optimization (MOO)     Pareto curve     genetic algorithm     CO2 separation    

水库优化调度的Pareto强度值SCE-UA算法

林剑艺,程春田,顾妍平,武新宇

《中国工程科学》 2007年 第9卷 第10期   页码 80-82

摘要:

提出求解水库优化调度问题的Pareto强度值SCE-UA算法,该方法将水库优化调度的约束优化问题转换成两个目标函数的无约束优化问题,一个为原问题的目标函数,另一个为违反约束条件的程度函数;对上述两个目标函数组成的向量个体,利用Pareto 优于关系和个体Pareto 强度值概念,实现个体的优劣比较和群体的优劣排序,在此基础上使用 SCE-UA算法求解。

关键词: 水库优化调度     约束优化     Pareto 优于关系     Pareto 强度值     SCE-UA算法    

Is there an inverted U-shaped curve?Empirical analysis of the Environmental Kuznets Curve in agrochemicals

Fei LI,Suocheng DONG,Fujia LI,Libiao YANG

《环境科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 276-287 doi: 10.1007/s11783-014-0700-y

摘要: As the largest contributor to water impairment, agriculture-related pollution has attracted the attention of scientists as well as policy makers, and quantitative information is being sought to focus and advance the policy debate. This study applies the panel unit root, heterogeneous panel cointegration, and panel-based dynamic ordinary least squares to investigate the Environmental Kuznets Curve on environmental issues resulting from use of agricultural synthetic fertilizer, pesticide, and film for 31 provincial economies in mainland China from 1989 to 2009. The empirical results indicate a positive long-run co-integrated relationship between the environmental index and real GDP per capita. This relationship takes on the inverted U-shaped Environmental Kuznets Curve, and the value of the turning point is approximately 10,000–13,000, 85,000–89,000 and over 160,000 CNY, for synthetic fertilizer nitrogen indicator, fertilizer phosphorus indicator and pesticide indicator, respectively. At present, China is subject to tremendous environmental pressure and should assign more importance to special agriculture-related environmental issues.

关键词: Environmental Kuznets Curve     agrochemical     China    

Learning curve of totally thoracoscopic pulmonary segmentectomy

Weibing Wu, Jing Xu, Wei Wen, Yue Yu, Xinfeng Xu, Quan Zhu, Liang Chen

《医学前沿(英文)》 2018年 第12卷 第5期   页码 586-592 doi: 10.1007/s11684-017-0566-z

摘要:

Totally thoracoscopic pulmonary segmentectomy (TTPS) is a feasible and safe technique that requires advanced thoracoscopic skills and knowledge of pulmonary anatomy. However, data describing the learning curve of TTPS have yet to be obtained. In this study, 128 patients who underwent TTPS between September 2010 and December 2013 were retrospectively analyzed to evaluate the learning curve and were divided chronologically into three phases, namely, ascending phase (A), plateau phase (B), and descending phase (C), through cumulative summation (CUSUM) for operative time (OT). Phases A, B, and C comprised 39, 33, and 56 cases, respectively. OT and blood loss decreased significantly from phases A to C (P <0.01), and the frequency of intraoperative bronchoscopy for target bronchus identification decreased gradually (A, 8/39; B, 4/33; C, 3/56; P = 0.06). No significant differences were observed in demographic factors, conversion, complications, hospital stay, and retrieved lymph nodes among the three phases. Surgical outcomes and techniques improved with experience and volume. CUSUMOT indicated that the learning curve of TTPS should be more than 72 cases.

关键词: thoracoscopic     segmentectomy     learning curve     CUSUM    

Pareto lexicographic α-robust approach and its application in robust multi objective assembly line balancing

null

《机械工程前沿(英文)》 2014年 第9卷 第3期   页码 257-264 doi: 10.1007/s11465-014-0294-x

摘要:

Robustness in most of the literature is associated with min-max or min-max regret criteria. However, these criteria of robustness are conservative and therefore recently new criteria called, lexicographic α-robust method has been introduced in literature which defines the robust solution as a set of solutions whose quality or jth largest cost is not worse than the best possible jth largest cost in all scenarios. These criteria might be significant for robust optimization of single objective optimization problems. However, in real optimization problems, two or more than two conflicting objectives are desired to optimize concurrently and solution of multi objective optimization problems exists in the form of a set of solutions called Pareto solutions and from these solutions it might be difficult to decide which Pareto solution can satisfy min-max, min-max regret or lexicographic α-robust criteria by considering multiple objectives simultaneously. Therefore, lexicographic α-robust method which is a recently introduced method in literature is extended in the current research for Pareto solutions. The proposed method called Pareto lexicographic α-robust approach can define Pareto lexicographic α-robust solutions from different scenarios by considering multiple objectives simultaneously. A simple example and an application of the proposed method on a simple problem of multi objective optimization of simple assembly line balancing problem with task time uncertainty is presented to get their robust solutions. The presented method can be significant to implement on different multi objective robust optimization problems containing uncertainty.

关键词: Pareto     lexicographic α-robust     assembly line balancing    

System-level Pareto frontiers for on-chip thermoelectric coolers

Sevket U. YURUKER, Michael C. FISH, Zhi YANG, Nicholas BALDASARO, Philip BARLETTA, Avram BAR-COHEN, Bao YANG

《能源前沿(英文)》 2018年 第12卷 第1期   页码 109-120 doi: 10.1007/s11708-018-0540-8

摘要: The continuous rise in heat dissipation of integrated circuits necessitates advanced thermal solutions to ensure system reliability and efficiency. Thermoelectric coolers are among the most promising techniques for dealing with localized on-chip hot spots. This study focuses on establishing a holistic optimization methodology for such thermoelectric coolers, in which a thermoelectric element’s thickness and the electrical current are optimized to minimize source temperature with respect to ambient, when the thermal and electrical parasitic effects are considered. It is found that when element thickness and electrical current are optimized for a given system architecture, a “heat flux vs. temperature difference” Pareto frontier curve is obtained, indicating that there is an optimum thickness and a corresponding optimum current that maximize the achievable temperature reduction while removing a particular heat flux. This methodology also provides the possible system level Δ ’s that can be achieved for a range of heat fluxes, defining the upper limits of thermoelectric cooling for that architecture. In this study, use was made of an extensive analytical model, which was verified using commercially available finite element analysis software. Through the optimization process, 3 pairs of master curves were generated, which were then used to compose the Pareto frontier for any given system architecture. Finally, a case study was performed to provide an in-depth demonstration of the optimization procedure for an example application.

关键词: thermoelectric cooling     thermal management     optimization     high flux electronics    

多目标优化与决策问题的演化算法

谢涛,陈火旺

《中国工程科学》 2002年 第4卷 第2期   页码 59-68

摘要: 为使演化算法的种群解 能尽快收敛并均匀分布于多目标问题的非劣最优域,多目标演化算法的研究热点集中在基于Pareto最优概念的 种群个体的比较与排序、适应值賦值与小生境技术等方面。介绍了多目标优化与决策技术的发展历史与分类方 法,分析了基于Pareto最优概念与不基于Pareto最优概念两大类的多目标演化算法,并详细比较与分析了几种 典型多目标演化算法。

关键词: 演化计算     多目标优化与决策     Pareto最优    

Numerical investigation of circle defining curve for two-dimensional problem with general boundaries

Chung Nguyen VAN

《结构与土木工程前沿(英文)》 2019年 第13卷 第1期   页码 92-102 doi: 10.1007/s11709-018-0472-8

摘要: The scaled boundary finite element method (SBFEM) is applied to the static analysis of two dimensional elasticity problem, boundary value problems domain with the domain completely described by a circular defining curve. The scaled boundary finite element equations is formulated within a general framework integrating the influence of the distributed body force, general boundary conditions, and bounded and unbounded domain. This paper investigates the possibility of using exact geometry to form the exact description of the circular defining curve and the standard finite element shape function to approximate the defining curve. Three linear elasticity problems are presented to verify the proposed method with the analytical solution. Numerical examples show the accuracy and efficiency of the proposed method, and the performance is found to be better than using standard linear element for the approximation defining curve on the scaled boundary method.

关键词: exact geometry     circular defining curve     general boundaries     SBFEM    

学习曲线及在工业生产运作研究中的应用综述

陈志祥

《中国工程科学》 2007年 第9卷 第7期   页码 82-88

摘要:

学习曲线是一种通过生产者行为学习与经验积累而得到改进的生产产出的特征函数,利用学习曲线可以科学地制定成本计划,改善作业计划、劳动定额与劳力规划,质量改善等。对国际上的研究文献、学习曲线的表现形式及其特点进行分析,探讨了几个新的应用动向。

关键词: 学习曲线     运作管理     行为研究    

Research on physical shape preserving curve reconstruction

TANG Kelun, ZHANG Xiangwei, CHENG Siyuan, XIONG Hanwei, ZHANG Hong

《机械工程前沿(英文)》 2007年 第2卷 第3期   页码 305-309 doi: 10.1007/s11465-007-0054-2

摘要: Fusion of various data is an effective way to improve the precision and efficiency of acquiring information in reverse engineering. A method of physical shape preserving curve reconstruction is proposed to better realize the data fusion of coordinate measuring machine (CMM) and visual information. From the principle of materials mechanics, the strain energy of the curve corresponding to the distortion is advanced as the internal energy, and the elastic potential energy of the curve is established, using a few precise measured data points as the equilibrium position, to be the external energy. On the basis of the principle of variation calculus, the basic spline finite element method (B-spline FEM) is used to determine the equilibrium position of curve deformation. Numerical simulation indicates that there is an extremely good agreement between the new fitted curve and the actual curve.

关键词: information     CMM     Numerical simulation     effective     coordinate measuring    

Interpolation of a spline developable surface between a curve and two rulings

Alicia CANTÓN,Leonardo FERNÁNDEZ-JAMBRINA

《信息与电子工程前沿(英文)》 2015年 第16卷 第3期   页码 173-190 doi: 10.1631/FITEE.14a0210

摘要: In this paper we address the problem of interpolating a spline developable patch bounded by a given spline curve and the first and the last rulings of the developable surface. To complete the boundary of the patch, a second spline curve is to be given. Up to now this interpolation problem could be solved, but without the possibility of choosing both endpoints for the rulings. We circumvent such difficulty by resorting to degree elevation of the developable surface. This is useful for solving not only this problem, but also other problems dealing with triangular developable patches.

关键词: Developable surfaces     Spline surfaces     Blossoms    

Principle and curve of planetary indexing cam mechanisms

LIU Ming-tao, ZHANG Ce, YANG Yu-hu

《机械工程前沿(英文)》 2006年 第1卷 第4期   页码 475-478 doi: 10.1007/s11465-006-0063-6

摘要: A new type of planetary indexing cam mechanism called type !c is presented. The transmission principle of type !c is discussed. Based on the principle of formation of conjugate tooth contour, the equations of the cam s pitch curve are derived. The continuity and symmetry of the cam s pitch curve are also analyzed. It can be concluded that: 1) This type has no output institution so the output precision can be improved; 2) The asymmetrical two-ring structure is used to overcome dead point and its phase angle is equal to (π - 2π/n); 3) The continuous condition of the cam s pitch curve is that the average transmission ratio is -n in an intermittent motion period.

关键词: continuity     planetary     average transmission     symmetry     intermittent    

Detection of void and metallic inclusion in 2D piezoelectric cantilever beam using impedance measurements

S. SAMANTA, S. S. NANTHAKUMAR, R. K. ANNABATTULA, X. ZHUANG

《结构与土木工程前沿(英文)》 2019年 第13卷 第3期   页码 542-556 doi: 10.1007/s11709-018-0496-0

摘要: The aim of current work is to improve the existing inverse methodology of void-detection based on a target impedance curve, leading to quick-prediction of the parameters of single circular void. In this work, mode-shape dependent shifting phenomenon of peaks of impedance curve with change in void location has been analyzed. A number of initial guesses followed by an iterative optimization algorithm based on univariate method has been used to solve the problem. In each iteration starting from each initial guess, the difference between the computationally obtained impedance curve and the target impedance curve has been reduced. This methodology has been extended to detect single circular metallic inclusion in 2D piezoelectric cantilever beam. A good accuracy level was observed for detection of flaw radius and flaw-location along beam-length, but not the precise location along beam-width.

关键词: piezoelectricity     impedance curve     mode shapes     inverse problem     flaw detection     curve shifting    

交换式以太网NC建模与实时性能分析

王晓欣,刘鲁源,刘昆,马津艳

《中国工程科学》 2006年 第8卷 第6期   页码 55-59

摘要:

交换式以太网的实时性能分析是工业以太网研究领域的一个热点课题,目前还没有一个有效的数学模型来对其进行描述。通过对典型交换机结构的分析,应用网络微积分理论建立了交换机的服务曲线模型,该模型将交换机中的数据流分为实时数据和非实时数据,并得到了最大延迟值和最大缓存需求值等,最大延迟为交换机的实时应用提供了理论边界值,最大缓存需求值为在实时工业环境中的交换机构建提供了理论参考。

关键词: 网络微积分     交换机     到达曲线     服务曲线     延迟    

三跨连续加劲梁悬索桥无索区梁段线形调整方法研究

戚兆臣,唐茂林,崔冰,董盟,王明

《中国工程科学》 2013年 第15卷 第8期   页码 37-41

摘要:

三跨连续加劲梁悬索桥在桥塔处梁段刚接及体系转换时如何保证无索区的线形平顺过渡、顺利进行体系转换、确保成桥线形与内力一致是一个难度较高的技术课题。本文讨论了国内外无索区梁段进行体系转换的方法,并以一座超千米的三跨连续钢箱梁悬索桥为例,实现其无索区加劲梁体系转换、线形调整和施工控制。

关键词: 悬索桥     加劲梁     无索区     线形    

标题 作者 时间 类型 操作

Multi-objective optimization of molten carbonate fuel cell system for reducing CO

Ramin ROSHANDEL,Majid ASTANEH,Farzin GOLZAR

期刊论文

水库优化调度的Pareto强度值SCE-UA算法

林剑艺,程春田,顾妍平,武新宇

期刊论文

Is there an inverted U-shaped curve?Empirical analysis of the Environmental Kuznets Curve in agrochemicals

Fei LI,Suocheng DONG,Fujia LI,Libiao YANG

期刊论文

Learning curve of totally thoracoscopic pulmonary segmentectomy

Weibing Wu, Jing Xu, Wei Wen, Yue Yu, Xinfeng Xu, Quan Zhu, Liang Chen

期刊论文

Pareto lexicographic α-robust approach and its application in robust multi objective assembly line balancing

null

期刊论文

System-level Pareto frontiers for on-chip thermoelectric coolers

Sevket U. YURUKER, Michael C. FISH, Zhi YANG, Nicholas BALDASARO, Philip BARLETTA, Avram BAR-COHEN, Bao YANG

期刊论文

多目标优化与决策问题的演化算法

谢涛,陈火旺

期刊论文

Numerical investigation of circle defining curve for two-dimensional problem with general boundaries

Chung Nguyen VAN

期刊论文

学习曲线及在工业生产运作研究中的应用综述

陈志祥

期刊论文

Research on physical shape preserving curve reconstruction

TANG Kelun, ZHANG Xiangwei, CHENG Siyuan, XIONG Hanwei, ZHANG Hong

期刊论文

Interpolation of a spline developable surface between a curve and two rulings

Alicia CANTÓN,Leonardo FERNÁNDEZ-JAMBRINA

期刊论文

Principle and curve of planetary indexing cam mechanisms

LIU Ming-tao, ZHANG Ce, YANG Yu-hu

期刊论文

Detection of void and metallic inclusion in 2D piezoelectric cantilever beam using impedance measurements

S. SAMANTA, S. S. NANTHAKUMAR, R. K. ANNABATTULA, X. ZHUANG

期刊论文

交换式以太网NC建模与实时性能分析

王晓欣,刘鲁源,刘昆,马津艳

期刊论文

三跨连续加劲梁悬索桥无索区梁段线形调整方法研究

戚兆臣,唐茂林,崔冰,董盟,王明

期刊论文