检索结果-内蒙古大学图书馆

approximation methods used to build the gas-lift performance curve based on reduced datasets: a comprehensive statistical comparison

引用

PETROLEUM SCIENCE AND TECHNOLOGY 2024年

作者： Marcu, Mariea Petr Gas Univ Ploiesti Well Drilling Prod & Transport Hydrocarbons Dept Ploiesti Romania

The gas-lift performance curve is essential for optimizing gas injection rate in a gas-lift well. Building this curve requires both an approximation method and a dataset from field measurements or nodal analysis. In low- automation oilfields, measured datasets are often limited in size and may be insufficient for building a gas-lift performance curve. The novelty of this paper lies in a comprehensive statistical comparison of interpolation, regression, and neural networks performances for different dataset sizes and point distributions. It highlights the limitations of these methods and their dependence on dataset configurations, especially for reduced datasets. The analysis shows that interpolation methods are less reliable, while some regression methods with few coefficients and neural networks perform better, enabling successful curve rebuilding. Statistical analysis identified an optimal distribution of points in a reduced dataset, where the curve-fitting performance is similar to that achieved with larger datasets. An optimal configuration should feature a wide range and standard deviation, including both low and high gas injection rate values, along with an intermediate value corresponding to the highest measured liquid rate. These findings are recommended as practical guidelines for configuring reduced datasets.

关键词： approximation methods gas-lift performance curve optimal distribution of points reduced dataset statistical analysis

来源：评论

学校读者我要写书评

暂无评论

approximation methods IN RADIAL TRANSMISSION LINE THEORY WITH APPLICATION TO HORNS

引用

PROCEEDINGS OF THE INSTITUTE OF RADIO ENGINEERS 1951年第8期39卷 959-965页

作者： LAEMMEL, AE MARCUVITZ, N OLINER, AA Microwave Research Institute Polytechnic Institute of Brooklyn Brooklyn NY USA

The radial transmission line theory provides a rigorous description of the propagation of electromagnetic energy in certain cylindrical regions. The complexity of direct calculation may be avoided by a simpler, although approximate, description based on the asymptotic identity of radial and uniform transmission line formulas at large radii. Approximate expressions are developed for input admittance, frequency sensitivity, and higher mode interaction effects on radial lines. Estimates of the order of accuracy are included, and applications are made to sectoral horns.

关键词： approximation methods Transmission line theory Electromagnetic waveguides Electromagnetic propagation Admittance Microwave propagation Electromagnetic scattering Surface waves Transmission lines Electromagnetic analysis

来源：评论

学校读者我要写书评

暂无评论

approximation methods in multidisciplinary analysis and optimization: a panel discussion

引用

STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION 2004年第5期27卷 302-313页

作者： Simpson, TW Booker, AJ Ghosh, D Giunta, AA Koch, PN Yang, RJ Penn State Univ Dept Mech & Nucl Engn University Pk PA 16802 USA Boeing Co Seattle WA 98124 USA Vanderplaats Res & Dev Inc Colorado Springs CO 80906 USA Sandia Natl Labs Optimizat & Uncertainty Estimat Dept Albuquerque NM 87185 USA Engineous Software Inc Adv Technol & Applicat Cary NC 27513 USA Ford Res & Adv Engn Optimizat & Robustness Safety R&A Dearborn MI 48124 USA

This paper summarizes the discussion at the approximation methods Panel that was held at the 9(th)AIAA/ISSMO Symposium on Multidisciplinary Analysis & Optimization in Atlanta, GA on September 2-4, 2002. The objective of the panel was to discuss the current state-of-the-art of approximation methods and identify future research directions important to the community. The panel consisted of five representatives from industry and government: (1) Andrew J. Booker from The Boeing Company, (2) Dipankar Ghosh from Vanderplaats Research & Development, (3) Anthony A. Giunta from Sandia National Laboratories, (4) Patrick N. Koch from Engineous Software, Inc., and (5) Ren-Jye Yang from Ford Motor Company. Each panelist was asked to (i) give one or two brief examples of typical uses of approximation methods by his company, (ii) describe the current state-of-the-art of these methods used by his company, (iii) describe the current challenges in the use and adoption of approximation methods within his company, and (iv) identify future research directions in approximation methods. Several common themes arose from the discussion, including differentiating between design of experiments and design and analysis of computer experiments, visualizing experimental results and data from approximation models, capturing uncertainty with approximation methods, and handling problems with large numbers of variables. These are discussed in turn along with the future directions identified by the panelists, which emphasized educating engineers in using approximation methods.

关键词： analysis of variance approximation methods design of experiments kriging response surfaces surrogate models

来源：评论

学校读者我要写书评

暂无评论

approximation methods for Optimal Active Fault Detection 22

Approximation Methods for Optimal Active Fault Detection

引用

22nd Mediterranean Conference on Control and Automation (MED)

作者： Simandl, Miroslav Skach, Jan Puncochar, Ivo Univ West Bohemia Fac Appl Sci Univ 8 Plzen 30614 Czech Republic Univ West Bohemia Ctr Excellence NTIS Plzen 30614 Czech Republic

ISBN: (纸本)9781479959013

In this paper the problem of active fault detection for a non-linear discrete-time stochastic system over an infinite time horizon is considered. The faults in the system are modeled by switching between fault-free and finitely many faulty models. The optimal active fault detector is derived by reformulating the original problem and solving corresponding Bellman's functional equation. A suboptimal solution is based on application of the value iteration or the policy iteration algorithms and a representation of the continuous hyper-state space by a uniform grid. A comparison of both algorithms for solving Bellman's functional equation is illustrated in a numerical example.

关键词： approximation theory continuous systems discrete time systems fault tolerant control fault trees infinite horizon nonlinear control systems state-space methods stochastic systems suboptimal control Bellman's functional equation active fault detection approximation methods continuous hyper-state space infinite time horizon nonlinear discrete-time stochastic system optimal active fault detection policy iteration algorithm value iteration Algorithm design and analysis approximation algorithms approximation methods Equations Fault detection Mathematical model Signal generators

来源：评论

学校读者我要写书评

暂无评论

approximation methods in multidisciplinary analysis and optimization: a panel discussion

Approximation methods in multidisciplinary analysis and opti...

引用

3rd ISSMO/AIAA Internet Conference on approximations in Optimization

关键词： analysis of variance approximation methods design of experiments kriging response surfaces surrogate models

来源：评论

学校读者我要写书评

暂无评论

approximation methods for the standard deviation of flow times in the G/G/s queue

Approximation methods for the standard deviation of flow tim...

引用

作者： Xiaofeng Zhao The University of Tennessee Knoxville

学位级别：博士

We provide approximation methods for the standard deviation of flow time in system for a general multi-server queue with infinite waiting capacity ( s G G / / ). The approximations require only the mean and standard deviation or the coefficient of variation of the inter-arrival and service time distributions, and the number of servers. These approximations are simple enough to be implemented in manual or spreadsheet calculations, but in comparisons to Monte Carlo simulations have proven to give good approximations (within % 10 ± ) for cases in which the coefficients of variation for the inter- arrival and service times are between 0 and 1. The approximations also have the desirable properties of being exact for the specific case of Markov queue model / / M M s, as well as some imbedded Markov queuing models ( 1 / /M Ek and 1 / / α E M ). The practical significance of this research is that (1) many real world queuing problems involve the s G G / / queuing systems, and (2) predicting the range of variation of the time in the system (rather than just the average) is needed for decision making. For example, one job shop facility with which the authors have worked, guarantees its customers a nine day turnaround time and must determine the minimum number of machines of each type required to achieve nine days as a "worst case" time in the system. In many systems, the "worst case" value of flow time is very relevant because it represents the lead time that can safely be promised to customers. To estimate this we need both the average and standard deviation of the time in system. The usefulness of our results stems from the fact that they are computationally simple and thus provide quick approximations without resorting to complex numerical techniques or Monte Carlo simulations. While many accurate approximations for the s G G / / queue have been proposed previously, they often result in algebraically intractable expressions. This hinders attempts to derive closed-form solut

关键词： Queuing System Standard Deviation Waiting Time Stochastic Process Heuristics s G G / approximation methods Priority Queue and Queuing Networks

来源：评论

学校读者我要写书评

暂无评论

Reliability assessment of cutting tool life based on surrogate approximation methods

引用

INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY 2014年第5-8期71卷 1197-1208页

作者： Salonitis, Konstantinos Kolios, Athanasios Cranfield Univ Mfg & Mat Dept Cranfield MK43 0AL Beds England Cranfield Univ Offshore Proc & Energy Engn Dept Cranfield MK43 0AL Beds England

A novel reliability estimation approach to the cutting tools based on advanced approximation methods is proposed. methods such as the stochastic response surface and surrogate modeling are tested, starting from a few sample points obtained through fundamental experiments and extending them to models able to estimate the tool wear as a function of the key process parameters. Subsequently, different reliability analysis methods are employed such as Monte Carlo simulations and first- and second-order reliability methods. In the present study, these reliability analysis methods are assessed for estimating the reliability of cutting tools. The results show that the proposed method is an efficient method for assessing the reliability of the cutting tool based on the minimum number of experimental results. Experimental verification for the case of high-speed turning confirms the findings of the present study for cutting tools under flank wear.

关键词： Tool wear Flank wear Structural reliability approximation methods Kriging SRSM

来源：评论

学校读者我要写书评

暂无评论

Regularity theory for the Isaacs equation through approximation methods

引用

ANNALES DE L INSTITUT HENRI POINCARE-ANALYSE NON LINEAIRE 2019年第1期36卷 53-74页

作者： Pimentel, Edgard A. Pontifical Catholic Univ Rio de Janeiro PUC Rio Dept Math BR-22451900 Rio De Janeiro RJ Brazil

In this paper, we propose an approximation method to study the regularity of solutions to the Isaacs equation. This class of problems plays a paramount role in the regularity theory for fully nonlinear elliptic equations. First, it is a model-problem of a non-convex operator. In addition, the usual mechanisms to access regularity of solutions fall short in addressing these equations. We approximate an Isaacs equation by a Bellman one, and make assumptions on the latter to recover information for the former. Our techniques produce results in Sobolev and Holder spaces;we also examine a few consequences of our main findings. (C) 2018 Elsevier Masson SAS. All rights reserved.

关键词： Isaacs equations Regularity theory Estimates in Sobolev and Holder spaces approximation methods

来源：评论

学校读者我要写书评

暂无评论

Influence of approximation methods on the design of the novel low-order fractionalized PID controller for aircraft system

引用

JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING 2024年第2期46卷 1-16页

作者： Idir, A. Bensafia, Y. Canale, L. Univ Mohamed Boudiaf Msila Dept Elect Engn Msila 28000 Algeria Univ Boumerdes Fac Hydrocarbons & Chem Appl Automat Lab Boumerdes Algeria Univ Bouira Dept Elect Engn Bouira 10000 Algeria CNRS LAPLACE Lab UMR 5213 Toulouse France

In this paper, the effect of approximation approaches on a novel low-order fractionalized proportional-integral-derivative (LOA/FPID) optimal controller based on the Harris Hawks optimization algorithm (HHOA) for airplane pitch angle control is studied. The Carlson, Oustaloup and Matsuda methods are used separately to approximate the fractional integral order of the fractionalized PID controller. This technique consists in introducing fractional-order integrators into the classical feedback control loop without modifying the overall equivalent closed loop transfer function. To validate the effectiveness of the suggested approach, performance indices, as well as transient and frequency responses, were used. The comparative study was performed, and the results show that the proposed reduced fractionalized PID based on HHO algorithm with Carlson controller is better in terms of percentage overshoot, settling time and rise time than other controllers.

关键词： Fractional calculus Fractionalized order controllers Integer order controllers Aircraft system Pitch angle approximation methods

来源：评论

学校读者我要写书评

暂无评论

Comparing offset curve approximation methods

引用

IEEE COMPUTER GRAPHICS AND APPLICATIONS 1997年第3期17卷 62-71页

作者： Elber, G Lee, IK Kim, MS Technion-Israel Institute of Technology Israel Pohang University of Science and Technology South Korea

Offset curves have diverse engineering applications, spurring extensive research on various offset techniques. This article is intended to fill an important gap in the literature. In a recent paper on offset curve approximation, the authors suggested a new approach based on approximating the offset circle instead of the offset curve itself. To demonstrate the effectiveness of this approach, they compared it extensively with previous methods, conducting qualitative as well as quantitative comparisons employing various contemporary offset approximation methods for freeform curves in the plane. They measured the efficiency of the offset approximation in terms of the number of control points generated while making the approximations within a prescribed tolerance.

关键词： approximation methods Spline Polynomials Surface topography Surface reconstruction approximation error Equations

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：