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INFLUENCE OF constraint method OF ELASTIC DIAPHRAGM ON NUMERICAL SIMULATION OF PRESSURE-COMPENSATING EMITTER

TRANSACTIONS OF THE ASABE 2021年第2期64卷 425-434页

作者： Chen, X. L. Wei, Z. Y. Wei, C. X. Ma, J. P. Chen, Z. Xi An Jiao Tong Univ Key Lab Mfg Syst Engn Xian Peoples R China

Numerical simulation is an important method for revealing the working principle and optimizing the design of drip emitters. The hydraulic performance of pressure-compensating (PC) emitters is determined by the interaction between the elastic diaphragm and the flow field;therefore, correct deformation of the elastic diaphragm is one of the factors determining the accuracy of numerical simulation of PC emitters. This study investigated the effects of three constraint methods of the elastic diaphragm on the numerical simulation of PC emitters. The three methods were fully fixed constraint (FFC), upper surface fixed constraint (UFC), and contact constraint (CC). Fluid-structure interaction (FSI) simulation was used to analyze the deformation characteristics of the elastic diaphragm, the flow field characteristics, and the flow rate of the PC emitter. The simulated diaphragm deformation and flow rates were compared with the results of a visual experiment and a hydraulic performance experiment, respectively. The simulation results showed that the constraint method affected the diaphragm deformation and flow field of the PC emitter. In comparing the simulation results with the experimental results, the CC method had the highest accuracy among the three constraint methods, but an extremely long computation time was required. The FFC method had the lowest accuracy but required less computation time. The accuracy of the UFC method was lower than CC and higher than FFC, but its computation time decreased by 60.03% compared with CC. This study provides a foundation for further research on the numerical simulation and design of PC emitters.

关键词： constraint method Deformation characteristics Flow field characteristics Fluid-structure interaction Visual experiment

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constraint method for laminated composite flat stiffened panel analysis using variational asymptotic method (VAM)

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THIN-WALLED STRUCTURES 2019年 145卷

作者： Kamineni, Jagath Narayana Burela, Ramesh Gupta Shiv Nadar Univ Mech Engn Dept Multifunct Composites Lab Greater Noida 201314 UP India

In this work, a new methodology is developed for constructing the stiffened panel structure. Here we introduce the constraint method to integrate the stiffener and plate. The geometric nonlinear analysis is performed to analyze the stiffened panel behavior in terms of load-deformation response curve. Variational Asymptotic method (VAM) is applied to analyze composite flat stiffened panels. The VAM development begins with the 3-D nonlinear strain energy functional which splits into a 1-D through-the-thickness analysis and a 2-D plate analysis. The 2-D constitutive law that is an output of 1-D analysis is used as an input to perform the 2-D nonlinear plate analysis. The integration of skin and the stiffener technique is implemented by introducing a constraint matrix. At the skin and stiffener interface, the developed constraint matrix is used in realization of 3-D displacements of stiffener and skin are same. The proposed approach is simple and reliable to address the complexity in analyzing stiffened structures. This methodology is developed using a computational symbolic tool Mathematica and the implemented computer program named as NASSVAM (Nonlinear Analysis of Stiffened Structures using Variational Asymptotic method). The obtained results from NASSVAM are compared and showed good agreement with the 3-D FEA results.

关键词： VAM Composite stiffened structures Geometric nonlinearity Warping constraint method NASSVAM

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An extended ε-constraint method for a multiobjective finite-horizon Markov decision process

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INTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH 2022年第5期29卷 3131-3160页

作者： Eghbali-Zarch, Maryam Tavakkoli-Moghaddam, Reza Azaron, Amir Dehghan-Sanej, Kazem Univ Tehran Coll Engn Sch Ind Engn Tehran *** Iran Kwantlen Polytech Univ Sch Business Vancouver BC V3W 2M8 Canada Univ British Columbia Sauder Sch Business Vancouver BC V6T 1Z4 Canada Islamic Azad Univ Sci & Res Branch Dept Ind Engn Tehran *** Iran

A Markov decision process (MDP) is an appropriate mathematical framework for analysis and modeling a large class of sequential decision-making problems. Real-world applications necessitate the evaluation of the value of a decision according to several conflicting objectives. This paper presents an extended epsilon-constraint method for a multiobjective finite-horizon MDP. This study integrates the epsilon-constraint method with the K-best policies algorithm to find the nondominated deterministic Markovian policies on the Pareto-optimal frontier. The proposed algorithm is evaluated on biobjective maintenance scheduling and machine running speed selection problems, and its performance is compared with a classic approach in the literature (weighted-sum, WS, method). Satisfying results show that the proposed algorithm obtains a good-quality Pareto frontier and has advantages over the WS method.

关键词： K‐ best policies algorithm Markov decision process weighted‐ sum method ϵ ‐ constraint method

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Application of multiobjective programming to water quality management in a river basin

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JOURNAL OF ENVIRONMENTAL MANAGEMENT 1996年第1期47卷 11-26页

作者： Lee, CS Wen, CG Institute of Environmental Engineering National Cheng Kung University Tainan 701 Taiwan

In this work on the management of water quality in a river basin by means of multiobjective programming, the programming model consists of three objectives that include simultaneously both economic and environmental factors. These objectives are the water quality of the rivers, the cost of wastewater treatment and the assimilative capacity of the rivers. In particular, this research is the first to take into account the last objective. For practical application, this paper proposes two methods of multiobjective programming, the constraint method and the step method. Furthermore, to illustrate the application of these techniques to water quality management problems, we use the basin of Tzeng-Wen River, Taiwan, as a case study. The results show that these methods work satisfactorily to improve the water quality, to ascertain the economic cost of wastewater treatment, and to allocate allowable loading in a manner of equality from non-inferior solutions. Alternatively, these methods provide important information for regulatory agencies to implement pollution control of river water. (C) 1996 Academic Press Limited

关键词： multiobjective programming constraint method step method non-inferior solutions water quality management assimilative capacity cost of wastewater treatment

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method for EV charging in stochastic smart microgrid operation with fuel cell and renewable energy source (RES) units

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IET ELECTRICAL SYSTEMS IN TRANSPORTATION 2020年第3期10卷 249-258页

作者： Tashviri, Mehdi Hatef Ghaffarzadeh, Navid Imam Khomeini Int Univ Fac Engn & Technol Elect Engn Dept Qazvin Iran

Nowadays, running out of fossil fuels and more attention to reduce environmental pollutions are essential factors for the growing use of electric vehicles (EVs). Owing to these factors, it is important to present a method, which schedules charging or discharging of EVs and simultaneously considers economic and environmental aspects of the problem. This study proposes a multi-objective optimisation programme for charging or discharging of EVs in a smart distribution system by taking advantage of advanced metering infrastructure and uses ae-constraint method for minimising operational costs and (CO2) emissions. Simulating stochastic patterns of EV owner driving behaviour as well as considering different models and types of EVs with the help of trip planning algorithm are the main advantages of this study. Investigating the multi-objective problem in two cases shows the effectiveness and flexibility of this algorithm in real cases. Besides, vehicle-to-grid capability of EVs was also considered. This method was tested on a 33-bus distribution test system for over 24 h. As the results show, the total amount of scheduled power, the peak-to-valley difference of daily load, transmission power loss, CO(2)emission, and the total operational cost are reduced by the trip planning programme and EV owner revenue is increased.

关键词： power distribution economics optimisation battery powered vehicles distributed power generation smart power grids fuel cell vehicles electric vehicle charging power generation scheduling air pollution EV charging stochastic smart microgrid operation fuel cell fossil fuels environmental pollutions economic aspects environmental aspects multiobjective optimisation programme charging discharging smart distribution system constraint method EV owner driving behaviour multiobjective problem 33-bus distribution test system total operational cost trip planning programme time 24 0 hour CO2

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Development of a simulation model for a three-dimensional wind velocity field using Tenes Algeria as a case study

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RENEWABLE & SUSTAINABLE ENERGY REVIEWS 2012年第1期16卷 29-36页

作者： Hacene, Fouad Boukli Abbes, Miloud Tahar Merzouk, Nachida Kasbadji Loukarfi, Larbi Mahmoudi, Hacene Goosen, Matheus F. A. Univ Hassiba Benbouli Fac Sci Chlef Algeria Univ Hassiba Benbouli Fac Technol Chlef Algeria CDER UDES Bou Ismail 42415 Tipaza Algeria Alfaisal Univ Riyadh Saudi Arabia

A mathematical simulation model was developed that can determine the three-dimensional wind velocity field over a complex terrain. The Tenes area in the Valley of Cheliff in Algeria was used as a case study. This region is exposed to south-west circulation that makes it favorable to the use of wind energy. Knowledge of wind fields is crucial for predicting the dispersion of pollutants, for forecasting meteorological weather, for fire spread prediction and in the design and implementation of wind turbines. By means of a mass consistent model, an in-house program was developed to calculate the three-dimensional wind velocity field in the study region. The model was supported by a numerical box in which flow through is allowed for in the upper and lateral boundaries. The bottom boundary through which no flow through occurs was determined by the topographic relief at the surface. From measured wind velocities, observed values were calculated by interpolation-extrapolation. Using an optimization method, the adjusted velocities were obtained from constraints, observed velocities and the continuity equation. The model was verified with wind point data, the relative error did not exceed 6%. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： constraint method Mass-consistent method Adjusted velocities Wind fields simulation Finite difference method Complex terrain

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Bi-criterion procedures to support logistics decision making: cost and uncertainty

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JOURNAL OF THE OPERATIONAL RESEARCH SOCIETY 2015年第12期66卷 2086-2091页

作者： Rijpkema, Willem A. Hendrix, Eligius M. T. Rossi, Roberto Wageningen Univ NL-6706 KN Wageningen Netherlands Univ Malaga E-29071 Malaga Spain Univ Edinburgh Edinburgh Midlothian Scotland

In practical decision making, one often is interested in solutions that balance multiple objectives. In this study we focus on generating efficient solutions for optimization problems with two objectives and a large but finite number of feasible solutions. Two classical approaches exist, being the constraint method and the weighting method, for which a specific implementation is required for this problem class. This paper elaborates specific straightforward implementations and applies them to a practical allocation problem, in which transportation cost and risk of shortage in supplied livestock quality are balanced. The variability in delivered quality is modelled using a scenario-based model that exploits historical farmer quality delivery data. The behaviour of both implementations is illustrated on this specific case, providing insight in (i) the obtained solutions, (ii) their computational efficiency. Our results indicate how efficient trade-offs in bi-criterion problems can be found in practical problems.

关键词： multi-objective optimization allocation problems scenario-based modelling constraint method weighting method stochastic programming

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On solving the multilevel rough interval linear programming problem

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JOURNAL OF INTELLIGENT & FUZZY SYSTEMS 2022年第4期42卷 3011-3028页

作者： Fathy, E. Ammar, E. Helmy, M. A. Helwan Univ Fac Sci Dept Math Helwan Egypt Tanta Univ Fac Sci Dept Math Tanta Egypt Inst Natl Planning Planning Tech Ctr Nasr City Egypt

In real-world problems, the parameters of optimization problems are uncertain. A class of multilevel linear programming (MLLP) with uncertainty problem models cannot be determined exactly. Hence, in this paper, we are concerned with studying the uncertainty of MLLP problems. The main motivation of this paper is to obtain the solution to a multilevel rough interval linear programming (MLRILP) problem. To obtain that, we start turning the problem into its competent crisp equivalent using the interval method. Moreover, we rely on three methods to address the problem of multiple levels. First, by applying the constraint method in which upper levels give satisfactory solutions that are reasonable in rank order to the lower levels, second, by an interactive approach that uses the satisfaction test function, and third, by the fuzzy approach that is based on the concept of the tolerance membership function. A numerical example is given for illustration and to examine the validity of the approach. An application to deduce the optimality for the cost of the solid MLLP transportation problem in rough interval environment is presented.

关键词： Multilevel linear programming constraint method interactive approach fuzzy approach rough interval programming

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Efficient source positioning method based on two stations using GROA and AOA measurements

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IET SIGNAL PROCESSING 2020年第2期14卷 56-63页

作者： Sun, Ting Dong, Chunxi Xidian Univ Sch Elect Engn Xian 710071 Shaanxi Peoples R China

By utilising the gain ratio of arrival (GROA) and angles of arrival (AOAs), three-dimensional source localisation with only two stations is studied. The weighted least squares (WLS) algorithm yields the typical closed-form solution, which is obtained by first establishing a set of linear equations and then determining the source position. However, the WLS solution exhibits poor performance at high noise levels. Hence, an efficient parameter augmented constraint method is proposed by extending the parameter space. The proposed method minimises the cost function by imposing a quadratic constraint such that the expectation of the cost function will attain its minimum value at the true solution. In addition, the proposed method yields an explicit algebraic solution and does not depend on a good initial guess;thus, there is no convergence problem. Theoretical analysis and simulation results verify the effectiveness of the proposed method.

关键词： direction-of-arrival estimation time-of-arrival estimation least squares approximations parameter space method minimises cost function quadratic constraint explicit algebraic solution efficient source GROA AOA measurements gain ratio AOAs three-dimensional source localisation weighted least squares algorithm closed-form solution linear equations source position WLS solution exhibits poor performance high noise levels efficient parameter constraint method

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Multi-Matching-Based Vision Navigation Referencing Map Tile

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INTERNATIONAL JOURNAL OF AERONAUTICAL AND SPACE SCIENCES 2021年第5期22卷 1119-1140页

作者： Shin, Seokhyun Min, Dongchan Lee, Jiyun Korea Adv Inst Sci & Technol KAIST Daejeon 34141 South Korea Korea Def Ind KDI Daejeon 34101 South Korea

Modern unmanned aerial vehicles (UAVs), including combat drones, are usually equipped with cameras for imaging. A camera is mainly used to increase the accuracy of the attack by ensuring stable-guided flight toward the target when the UAV detects the target in the terminal phase. Despite the high cost of these pieces of equipment, their utilization is in fact low, except during the final stage. The method proposed here extends the range of use of a UAV-mounted camera to the navigation stage. When GPS is unable to estimate the position due to jamming or a sensor error, the possibility of using the position estimation value calculated through vision navigation is described.

关键词： Vision navigation GPS-denied environment 3D structure landmark Map tile Frame matching Pixel-meter coordinate transformation Vincenty’ s formulae Pseudo frame Edge detection Edge matching Hough transform Hausdorff distance Iterative closest point constraint method

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