作者:
Li, Fang-FangQiu, JunWei, Jia-HuaChina Agr Univ
Coll Water Resources & Civil Engn Beijing 100083 Peoples R China Tsinghua Univ
Dept Hydraul Engn State Key Lab Hydrosci & Engn Beijing 100084 Peoples R China Qinghai Univ
State Key Lab Plateau Ecol & Agr Xining 810016 Qinghai Peoples R China
Hydropower can be an ideal compensation for fluctuant photovoltaic (PV) power due to its flexibility. In this study, a multiobjective optimization model considering energy generation and consumption simultaneously for...
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Hydropower can be an ideal compensation for fluctuant photovoltaic (PV) power due to its flexibility. In this study, a multiobjective optimization model considering energy generation and consumption simultaneously for a hydro-PV hybrid power system is proposed. With the daily mean radiation intensity and temperature, the PV power output is calculated. Taking reservoir release as the decision variable, the total energy generation of the hydro-PV system is maximized. Meanwhile, the gap between the energy generation and the energy consumption is minimized to reduce the abandoned PV power or hydropower. The proposed multiobjective model is optimized by Non-dominated Sorting Genetic Algorithms-II (NSGA-II). The Longyangxia Project, the largest hydro-photovoltaic hybrid power system in the world is taken as the study case to estimate the optimal operational strategies for different objectives in wet year, normal year, and dry year, respectively. The optimal operation process of the reservoir is presented, which is instructive for the operation in the future.
The bending of simply supported composite plates is analyzed using a direct collocation meshless numerical method. In order to optimize node distribution the Direct MultiSearch (DMS) for multi-objective optimization m...
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The bending of simply supported composite plates is analyzed using a direct collocation meshless numerical method. In order to optimize node distribution the Direct MultiSearch (DMS) for multi-objective optimization method is applied. In addition, the method optimizes the shape parameter in radial basis functions. The optimization algorithm was able to find good solutions for a large variety of nodes distribution. (C) 2014 Elsevier Ltd. All rights reserved.
To realize the goal of environmental sustainability, improving energy efficiency in buildings is a major priority worldwide. However, the practical design of green building envelopes for energy conservation is a highl...
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To realize the goal of environmental sustainability, improving energy efficiency in buildings is a major priority worldwide. However, the practical design of green building envelopes for energy conservation is a highly complex optimization problem, and architects must make multiobjective decisions. In practice, methods such as multicriteria analyses that entail capitalizing on possibly many (but in nearly any case limited) alternatives are commonly employed. This study investigated the feasibility of applying a multiobjective optimal model on building envelope design (MOPBEM), which involved integrating a building envelope energy performance model with a multiobjective optimizer. The MOPBEM was established to provide a reference for green designs. A nondominated sorting genetic algorithm-II (NSGA-lI) was used to achieve a tradeoff design set between three conflicting objectives, namely minimizing the envelope construction cost (ENVCOST), minimizing the envelope energy performance (ENVLOAD), and maximizing the window opening rate (WOPR). A real office building case was designed using the MOPBEM to identify the potential strengths and weaknesses of the proposed MOPBEM. The results showed that a high ENVCOST was expended in simultaneously satisfying the low ENVLOAD and high WOPR. Various designs exhibited obvious cost reductions compared with the original architects' manual design, demonstrating the practicability of the MOPBEM. (C) 2016 Elsevier Ltd. All rights reserved.
作者:
Creaco, EnricoHaidar, HatemUniv Pavia
Dipartimento Ingn Civile & Architettura Via Ferrata 3 I-27100 Pavia Italy Univ Exeter
Coll Engn Phys & Math Sci Exeter EX4 4QF Devon England Univ Adelaide
Sch Civil Environm & Min Engn Adelaide SA 5005 Australia Lebanese Univ
Dept Civil Engn Rafic Hariri CampusHadath BP 2 Baabda Lebanon
This paper presents a novel methodology for optimizing simultaneously the installation of control valves and the creation of district metered areas (DMAs) in water distribution networks (WDNs). This methodology was de...
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This paper presents a novel methodology for optimizing simultaneously the installation of control valves and the creation of district metered areas (DMAs) in water distribution networks (WDNs). This methodology was developed through the multiobjective approach, by considering, as decisional variables, the sites for control valve installation and isolation valve closure. The proposed algorithm is based on the hybrid combination of three algorithms, a multiobjective genetic algorithm, which is entrusted with valve site search, and two embedded algorithms, the first based on iterated linear programming (LP) and the second based on graph theory, aimed at searching for the optimal settings of control valves and at partitioning the WDN into DMAs, respectively. The hybrid algorithm attempts to find optimal solutions in the trade-off between the following objective functions to be optimized simultaneously: total installation cost, daily leakage volume, and demand uniformity across DMAs. The applications to a small Lebanese WDN proved that the methodology can find, especially for high values of the total installation cost, effective control valve installations, and isolation valve closures in terms of leakage abatement while obtaining a uniform distribution of demands across DMAs.
In this paper, a framework is developed for identifying a limited number of representative solutions of a multiobjective optimization problem concerning the inspection intervals of the components of a safety system of...
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In this paper, a framework is developed for identifying a limited number of representative solutions of a multiobjective optimization problem concerning the inspection intervals of the components of a safety system of a nuclear power plant. Pareto Front solutions are first clustered into "families", which are then synthetically represented by a "head of the family" solution. Three clustering methods are analyzed. Level Diagrams are then used to represent, analyse and interpret the Pareto Fronts reduced to their head-of-the-family solutions. Two decision situations are considered: without or with decision maker preferences, the latter implying the introduction of a scoring system to rank the solutions with respect to the different objectives: a fuzzy preference assignment is then employed to this purpose. The results of the application of the framework of analysis to the problem of optimizing the inspection intervals of a nuclear power plant safety system show that the clustering-based reduction maintains the Pareto Front shape and relevant characteristics, while making it easier for the decision maker to select the final solution. (C) 2010 Elsevier Ltd. All rights reserved.
The current study focuses on the multiobjective optimization of an ultrasound intensified and ionic liquid catalyzed in situ transesterification of wet microalgae for renewable biodiesel production. The process is dev...
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The current study focuses on the multiobjective optimization of an ultrasound intensified and ionic liquid catalyzed in situ transesterification of wet microalgae for renewable biodiesel production. The process is developed and simulated in Aspen Plus V10 simulator and an excel based multiobjective optimization (EMOO) programme for the elitist non-dominated sorting genetic algorithm-II is used for optimization. Total Annual Cost, i.e. TAC (representing economics), organic waste (representing cleaner production), individual risk, i.e. IR (representing risk to the human capital), and CO2 emission (representing environment) are chosen as the objectives for the constrained optimization of this process. The results show that the TAC reduces with the increase in the generation of organic waste, CO2 emission and IR. This article contemplates and articulates the reasons for the obtained trade-offs between objectives. The quantitative trade-offs between objectives aid to the better decision making about the process design and operation while satisfying economic, environmental and safety concerns. Finally, net flow method (NFM) has been implemented for the identification of best suitable solution in the Pareto-optimal fronts. Simultaneous optimization of all four objectives resulted in the impressive savings in TAC (~15%), organic waste (~33%), IR (~9%), and CO2 emission (~37%).& nbsp;(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
In this paper, the damping capacity and the structural influence of the hard coating on the given bladed disk are optimized by the non-dominated sorting genetic algorithm (NSGA-II) coupled with the Kriging surrogate m...
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In this paper, the damping capacity and the structural influence of the hard coating on the given bladed disk are optimized by the non-dominated sorting genetic algorithm (NSGA-II) coupled with the Kriging surrogate model. Material and geometric parameters of the hard coating are taken as the design variables, and the loss factors, frequency variations and weight gain are considered as the objective functions. Results of the bi-objective optimization are obtained as curved line of Pareto front, and results of the triple-objective optimization are obtained as Pareto front surface with an obvious frontier. The results can give guidance to the designer, which can help to achieve more superior performance of hard coating in engineering application.
The structure and trigger control strategy have become the most important factors that restrict the performance of the multistage synchronous induction coilgun (MSSICG). However, it is still a difficult task to design...
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The structure and trigger control strategy have become the most important factors that restrict the performance of the multistage synchronous induction coilgun (MSSICG). However, it is still a difficult task to design MSSICG under overload constraint due to coupling between the multiple parameters. In this paper, the maximization of the emission efficiency and acceleration stationarity is treated as a multiobjective optimization problem. By analyzing the relationship between the number of turns and the other structural parameters of the launch, the multiobjective optimization model of MSSICG is established by the current filament method which was verified by the experimental data and finite-element method. And then the second generation nondominated sorting genetic algorithm (NSGA-II) and multiobjective particle swarm optimization (MOPSO) were employed to optimize the model in order to maximize the energy transfer efficiency while achieving the smooth acceleration of the armature. With the formulated optimization model, a five-stage synchronous induction coilgun is optimized as a special case. A decision-making procedure based on the fuzzy membership function is used for obtaining best compromise solution from the set of Pareto-solutions obtained through NSGA-II and MOPSO. In addition, the optimization performance of the proposed multiobjective optimization model and the single-objective optimization model of the MSSICG was compared. The result of optimization shows that the proposed multiobjective optimization model of MSSICG can effectively improve the performance of the coilgun compared with the single-objective optimization model which takes of the launch velocity and overload acceleration as the combination objective function or only the launch velocity.
A methodology of multiobjective design optimization of ceramic-metal composite plates with functionally graded materials, with properties varying through the thickness direction, obtained by an adequate variation of v...
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A methodology of multiobjective design optimization of ceramic-metal composite plates with functionally graded materials, with properties varying through the thickness direction, obtained by an adequate variation of volume fractions of the constituent materials, is presented in this paper. Constrained optimization is conducted for different behavior objectives like the maximization of buckling load or fundamental natural frequency. Mass minimization and material cost minimization are also considered. The optimization problems are constrained by stress based failure criteria and other structural response constraints or manufacturing limitations. The design variables are the index of the power-law distribution in the metal-ceramic graded material and the thicknesses of the graded material and/or the metal and ceramic faces. An equivalent single layer finite element plate model having a displacement field based on a higher order shear deformation theory, accounting for the temperature dependency of the material properties, was developed and validated for the analysis of through-the-thickness ceramic-metal functionally graded plates. The optimization problems are solved with two direct search derivative-free algorithms: GLODS (Global and Local optimization using Direct Search) and DMS (Direct MultiSearch). DMS, the multiobjective optimization solver, is started from a set of local minimizers which are initially determined by the global optimizer algorithm GLODS for each one of the objective functions. (C) 2017 Elsevier Ltd. All rights reserved.
In hatch process scheduling, production trade-offs arise from the simultaneous consideration of different objectives. Economic goals are expressed in terms of plant profitability and productivity, whereas the environm...
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In hatch process scheduling, production trade-offs arise from the simultaneous consideration of different objectives. Economic goals are expressed in terms of plant profitability and productivity, whereas the environmental objectives are evaluated by means of metrics originated from the use of life cycle assessment methodology. This work illustrates a novel approach for decision making by using multiobjective optimization. In addition, different metrics are proposed to select a possible compromise based on the distance to a nonexistent utopian solution, whose objective function values are all optimal. Thus, this work provides a deeper insight into the influence of the metrics selection for both environmental and economic issues while considering the trade-offs of adopting a particular schedule. The use of this approach is illustrated through its application to a case study related to a multiproduct acrylic fiber production plant, special attention is put to the influence of product changeovers. (C) 2010 American Institute of Chemical Engineers AIChE J, 57: 2766-2782, 2011
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