Search results for "Principle"
showing 10 items of 1023 documents
The Hu-Washizu variational principle for the identification of imperfections in beams
2008
This paper presents a procedure for the identification of imperfections of structural parameters based on displacement measurements by static tests. The proposed procedure is based on the well-known Hu–Washizu variational principle, suitably modified to account for the response measurements, which is able to provide closed-form solutions to some inverse problems for the identification of structural parameter imperfections in beams. Copyright © 2008 John Wiley & Sons, Ltd.
On Ekeland's variational principle in partial metric spaces
2015
In this paper, lower semi-continuous functions are used to extend Ekeland's variational principle to the class of parti al metric spaces. As consequences of our results, we obtain some fixed p oint theorems of Caristi and Clarke types.
State feedback control against sensor faults for Lipschitz nonlinear systems via new sliding mode observer techniques
2011
This paper investigates the problem of simultaneous state and fault estimation and observer-based fault tolerant controller design for Lipschitz nonlinear systems with sensor failure. A new estimation technique is presented in this paper to deal with this design problem. In the proposed approaches, the original system is first augmented by a descriptor model transformation, then a new Proportional and Derivative sliding mode observer technique is developed to obtain accurate estimations of both system states and sensor faults. The designing observer is generalized from the PD observer in [3], but is not a trivial extension. Based on the state estimates, a observer-based control strategy is …
A Generalized Framework for Optimal Sizing of Distributed Energy Resources in Micro-Grids Using an Indicator-Based Swarm Approach
2014
In this paper, a generalized double-shell framework for the optimal design of systems managed optimally according to different criteria is developed. Optimal design is traditionally carried out by means of minimum capital and management cost formulations and does not typically consider optimized operation. In this paper, the optimized multiobjective management is explicitly considered into the design formulation. The quality of each design solution is indeed defined by the evaluation of operational costs and capital costs. Besides, the assessment of the operational costs term is deduced by means of the solution of a multiobjective optimization problem. Each design solution is evaluated usin…
Performance improvement of a novel combined water turbine
2020
Abstract Nowadays, industrials and researchers are looking for renewable energy resources due to the increase of energy demand. Recently, the ability of combined turbines in harnessing energy from water current has increased their renewed interest. However, there still exist a big knowledge gap to select the optimal design of these turbines. In this paper, systematic studies of stand-alone helical Savonius and delta bladed Darrieus turbines were carried out using experimental methods as a precursor to analyze their roles in hybrid configuration. By varying the attachment angle, two hybrid configurations were tested experimentally. Using the optimal attachment angle, six hybrid configuration…
A double-shell design approach for multiobjective optimal design of microgrids
2010
This work develops a new double shell approach to optimal design for multi-objective optimally managed systems. The cost of each design solution can be defined by the evaluation of operational issues and capital costs. In most systems, the correct definition of operational issues can be deduced by means of the solution of a multi-objective optimization problem. The evaluation of each design solution must thus be deduced using the outcome of a multi-objective optimization run, namely a Pareto hyper-surface in the n-dimensional space of operational objectives. In the literature, the design problem is usually solved by considering a single objective formulation of the operational issue. In thi…
Comparison between Entropy and Resilience as Indirect Measures of Reliability in the Framework of Water Distribution Network Design
2014
Abstract The aim of this paper is to investigate which between the entropy and resilience indices represents a better indirect measure of reliability in the framework of water distribution network design. The methodology adopted consisted of (a) multi-objective optimizations performed in order to minimize costs and maximize reliability, expressed by means of one of the indirect indices at time; (b) retrospective performance assessment of the solutions of Pareto fronts obtained. Two case studies of different topological complexity were considered. Results showed that indices based on energetic concepts (resilience and modified resilience) represent a better compact estimate of reliability th…
Fixed domain approaches in shape optimization problems with Dirichlet boundary conditions
2009
Fixed domain methods have well-known advantages in the solution of variable domain problems including inverse interface problems. This paper examines two new control approaches to optimal design problems governed by general elliptic boundary value problems with Dirichlet boundary conditions. Numerical experiments are also included peerReviewed
Water quality sensor placement: a multi-objective and multi-criteria approach
2021
[EN] To satisfy their main goal, namely providing quality water to consumers, water distribution networks (WDNs) need to be suitably monitored. Only well designed and reliable monitoring data enables WDN managers to make sound decisions on their systems. In this belief, water utilities worldwide have invested in monitoring and data acquisition systems. However, good monitoring needs optimal sensor placement and presents a multi-objective problem where cost and quality are conflicting objectives (among others). In this paper, we address the solution to this multi-objective problem by integrating quality simulations using EPANET-MSX, with two optimization techniques. First, multi-objective op…
Comparison of Numerical Methods in the Contrast Imaging Problem in NMR
2013
International audience; In this article, the contrast imaging problem in nuclear magnetic resonance is modeled as a Mayer problem in optimal control. A first synthesis of locally optimal solutions is given in the single-input case using geometric methods based on Pontryagin's maximum principle. We then compare these results using direct methods and a moment-based approach, and make a first step towards global optimality. Finally, some preliminary results are given in the bi-input case.