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Artigos de revistas sobre o tema "Problème de minimisation"

Autor: Grafiati

Publicado: 12 de outubro de 2024

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1

Malassis, Louis. "Politiques et stratégies alimentaires". Économies et Sociétés. Série Progrès en agriculture 19, n.º 718 (1985): 3–22. http://dx.doi.org/10.3406/esag.1985.1638.

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Cet article est une tentative pour établir une «problématique des stratégies alimentaires». Après quelques définitions préliminaires il envisage les objectifs, les méthodes (spécialisation internationale ou autosuffisance), les moyens (modèles techniques) des politiques et le problème de la minimisation du coût social de l’alimentation.

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Bouglet, Tania, Thomas Lanzi e J. C. Vergnaud. "Incertitude scientifique et décision publique : le recours au Principe de précaution". Recherches économiques de Louvain 72, n.º 2 (2006): 109–27. http://dx.doi.org/10.1017/s0770451800044602.

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Résumé:Dans cet article, nous formalisons deux critères de décisions qui tentent de rendre compte de deux logiques différentes d'interprétation du Principe de précaution. Le premier critère correspond à la maximisation du minimum de l'espérance d'utilité alors que le second critère correspond à la minimisation du maximum de l'espérance de regret. Les deux critères de décisions sont appliqués à un problème économique où l'incertitude est mesurée par une famille de probabilités. Nous montrons qu'il existe un intervalle de probabilités sur lequel les choix relatifs aux deux critères divergent. Plus particulièrement, nous montrons que sur cet intervalle, le second critère à la différence du premier, conduit toujours à retenir la décision la plus précautionneuse, les décisions étant identiques sur les autres intervalles.

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Chouaf, Seloua, e Youcef Smara. "Méthode de sélection des bandes à base de l'Analyse en Composantes Indépendantes appliquée aux images hyperspectrales de télédétection". Revue Française de Photogrammétrie et de Télédétection, n.º 204 (8 de abril de 2014): 57–62. http://dx.doi.org/10.52638/rfpt.2013.22.

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Les données hyperspectrales se caractérisent par une importante dimension spectrale qui atteint quelques centaines de bandes étroites et contigües. Le volume occupé par ces images est non négligeable et fait que des taches usuelles telles que : le stockage, le traitement et l'analyse soient alourdies. Pour pallier ce problème et garantir une meilleure exploitation de ces données, nous proposons par le présent article, une méthode de réduction qui vise à créer un espace de représentation de dimension moindre, informatif et libéré des redondances tout en préservant la signification physique des bandes.Vu le pouvoir de séparation de l'analyse en composantes indépendantes «ACI», reconnu dans le cas des données multidimensionnelles à grand volume, nous l'exploitons pour extraire un ensemble de composantes statistiquement indépendantes obtenues par la minimisation de la gaussiannité. Différents degrés d'importance sont affectés aux bandes spectrales, permettant leur classement. Finalement, nous appliquons une sélection à l'ensemble des bandes classées et nous retenons les plus informatives afin de construire l'espace de représentation spectral réduit. Pour nos tests, nous avons appliqué l'ACI en considérant d'une part, une orthogonalisation à déflation (poursuite de projections, composantes ordonnées) et d'autre part, une orthogonalisation symétrique (estimation globale, composantes désordonnées). On suggère pour le cas symétrique, d'ajuster les données originales à un bruit additif afin d'obtenir des composantes indépendantes ordonnées (suivant le rapport signal à bruit). Les résultats recueillis montrent que la méthode proposée assure la réduction du cube hyperspectral avec d'acceptables rapports dimension-représentativité.

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Albers, C. J., F. Critchley e J. C. Gower. "Quadratic minimisation problems in statistics". Journal of Multivariate Analysis 102, n.º 3 (março de 2011): 698–713. http://dx.doi.org/10.1016/j.jmva.2009.12.018.

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DeBenedictis, Andrew, e Timothy J. Atherton. "Shape minimisation problems in liquid crystals". Liquid Crystals 43, n.º 13-15 (28 de julho de 2016): 2352–62. http://dx.doi.org/10.1080/02678292.2016.1209699.

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McDiarmid, Colin. "Pattern minimisation in cutting stock problems". Discrete Applied Mathematics 98, n.º 1-2 (outubro de 1999): 121–30. http://dx.doi.org/10.1016/s0166-218x(99)00112-2.

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Hill, Robin D. "Dual periodicity in -norm minimisation problems". Systems & Control Letters 57, n.º 6 (junho de 2008): 489–96. http://dx.doi.org/10.1016/j.sysconle.2007.11.007.

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Aussel, D., e C. C. Chou. "Asymptotical well behaviour for constrained minimisation problems". Bulletin of the Australian Mathematical Society 66, n.º 3 (dezembro de 2002): 499–516. http://dx.doi.org/10.1017/s000497270004034x.

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This paper is devoted to the study of the links between stationary sequence and minimising sequence for constrained minimisation problems. The constraint set is not supposed to be convex and no differentiability assumption is made on the objective function. New tools are developed in this general framework and we prove a necessary and a sufficient condition for such problems to have a “constrained asymptotical well behaviour” (that is, each stationary sequence is a minimising sequence). Our work extend that of Auslender, Cominetti and Crouzeix.

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Albers, C. J., F. Critchley e J. C. Gower. "Applications of quadratic minimisation problems in statistics". Journal of Multivariate Analysis 102, n.º 3 (março de 2011): 714–22. http://dx.doi.org/10.1016/j.jmva.2010.11.009.

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Huy, N. Q., V. Jeyakumar e G. M. Lee. "Sufficient global optimality conditions for multi-extremal smooth minimisation problems with bounds and linear matrix inequality constraints". ANZIAM Journal 47, n.º 4 (abril de 2006): 439–50. http://dx.doi.org/10.1017/s1446181100010063.

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AbstractIn this paper, we present sufficient conditions for global optimality of a general nonconvex smooth minimisation model problem involving linear matrix inequality constraints with bounds on the variables. The linear matrix inequality constraints are also known as “semidefinite” constraints which arise in many applications, especially in control system analysis and design. Due to the presence of nonconvex objective functions such minimisation problems generally have many local minimisers which are not global minimisers. We develop conditions for identifying global minimisers of the model problem by first constructing a (weighted sum of squares) quadratic underestimator for the twice continuously differentiable objective function of the minimisation problem and then by characterising global minimisers of the easily tractable underestimator over the same feasible region of the original problem. We apply the results to obtain global optimality conditions for optinusation problems with discrete constraints.

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Dai, Jisheng, Weichao Xu, Jin Zhang e Chunqi Chang. "Homotopy algorithm for l 1 ‐norm minimisation problems". IET Signal Processing 9, n.º 1 (fevereiro de 2015): 1–9. http://dx.doi.org/10.1049/iet-spr.2013.0338.

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Rooney, Siobhan, Aideen Freyne, Gabrielle Kelly e John O'Connor. "Differences in the quality of life of two groups of drug users". Irish Journal of Psychological Medicine 19, n.º 2 (junho de 2002): 55–59. http://dx.doi.org/10.1017/s0790966700006960.

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AbstractObjectives: The aim of this study was to compare aspects of the quality of life of drug users on a methadone maintenance programme to drug users on a harm minimisation programme.Method: Thirty-six clients attending the harm minimisation programme in the National Drug Treatment Centre, Dublin, were matched for age and sex to 36 clients on the methadone maintenance programme. All were interviewed with the SF-36 Health Survey Questionnaire to measure health related quality of life and with the Hospital Anxiety and Depression Scale (HADs) to measure psychological morbidity.Results: More clients from the harm minimisation programme had previous psychiatric problems than clients on the methadone maintenance programme, with an odds ratio of 4.3 CI(1.2,15.2). On the HADs, clients on the methadone maintenance programme had significantly lower depression scores than clients on the harm minimisation programme. In addition more clients on the harm minimisation programme were severely depressed than clients on the methadone maintenance programme. On the UK SF-36 Scale, clients on the harm minimisation programme perceived a significantly greater deterioration in ‘change in health’ over the previous year than clients on the methadone maintenance programme.Conclusions: Although clients on a methadone maintenance programme had an improved perception of their quality of life in relation to psychological and overall health function from the previous year, compared to clients on a harm minimisation programme, there still existed varying degrees of psychopathology in both groups which need to be considered when providing future services for drug users.

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Kimura, M., e P. van Meurs. "Regularity of the minimiser of one-dimensional interaction energies". ESAIM: Control, Optimisation and Calculus of Variations 26 (2020): 27. http://dx.doi.org/10.1051/cocv/2019043.

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We consider both the minimisation of a class of nonlocal interaction energies over non-negative measures with unit mass and a class of singular integral equations of the first kind of Fredholm type. Our setting covers applications to dislocation pile-ups, contact problems, fracture mechanics and random matrix theory. Our main result shows that both the minimisation problems and the related singular integral equations have the same unique solution, which provides new regularity results on the minimiser of the energy and new positivity results on the solutions to singular integral equations.

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Katzourakis, Nikos. "A minimisation problem in L∞ with PDE and unilateral constraints". ESAIM: Control, Optimisation and Calculus of Variations 26 (2020): 60. http://dx.doi.org/10.1051/cocv/2019034.

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We study the minimisation of a cost functional which measures the misfit on the boundary of a domain between a component of the solution to a certain parametric elliptic PDE system and a prediction of the values of this solution. We pose this problem as a PDE-constrained minimisation problem for a supremal cost functional in L∞, where except for the PDE constraint there is also a unilateral constraint on the parameter. We utilise approximation by PDE-constrained minimisation problems in Lp as p →∞ and the generalised Kuhn-Tucker theory to derive the relevant variational inequalities in Lp and L∞. These results are motivated by the mathematical modelling of the novel bio-medical imaging method of Fluorescent Optical Tomography.

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Peldschus, Friedel. "RESEARCH ON THE SENSITIVITY OF MULTI- CRITERION EVALUATION METHODS/SENSIBILITÄTSUNTERSUCHUNGEN ZU METHODEN DER MEHRKRITERIELLEN ENTSCHEIDUNGEN". JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 7, n.º 4 (31 de agosto de 2001): 276–80. http://dx.doi.org/10.3846/13921525.2001.10531736.

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Investigations into the multi-criterion evaluations have been performed for different purposes for more than 30 years. Nevertheless, up to now there are no common rules how to apply multi-criterion methods of evaluation and how to interpret their results. But the solutions of the problem must be found. The investigations are based on the joint programme LEVI developed by the VGTU and the Leipzig HSTEC. In accordance with the programme, for solving the problem a matrix is created in which all solution variants are evaluated by the same criteria. For the transformation of initial data different methods are used. Besides, the problem solution may be oriented to a choice of a variant and the determination of an optimal sequence or to the determination of the rational behaviour balance of two adversely interested groups. The maximisation, minimisation and mixed problems are distinguished. In case of the last mentioned problems the meanings may be unsuitable and expressions about the maximisation or minimisation too strong. When solving the problem of maximisation by different transformation methods, similar curves are obtained and the results are not dispersed heavily. In case of the minimisation, when solving according to different transformations, a considerable deviation of results has been noticed. The investigations also disclosed that solutions may vary depending on the optimisation goal. Dispersion of results in case of minimisation is stronger than in case of maximisation. When analysing different transformations, the vectorial transformation is regarded as “neutral” and there is no sense to include it into comparison. In case of the minimisation problem, linear transformations should be investigated in a more detailed way.

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Pulch, R. "Initial-boundary value problems of warped MPDAEs including minimisation criteria". Mathematics and Computers in Simulation 79, n.º 2 (novembro de 2008): 117–32. http://dx.doi.org/10.1016/j.matcom.2007.10.006.

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Krishnamoorthy, M., A. T. Ernst e D. Baatar. "Algorithms for large scale Shift Minimisation Personnel Task Scheduling Problems". European Journal of Operational Research 219, n.º 1 (maio de 2012): 34–48. http://dx.doi.org/10.1016/j.ejor.2011.11.034.

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18

Andjouh, Amar, e Mohand Ouamer Bibi. "Support solving method for box-constrained indefinite quadratic minimisation problems". International Journal of Mathematical Modelling and Numerical Optimisation 12, n.º 4 (2022): 390. http://dx.doi.org/10.1504/ijmmno.2022.126556.

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Haji Ali, Nor Eeda, Ho Chin Siong, Halmi Zainol e Nurain Mohd Talmizi. "Socio-Demographic Influencing Behaviour against Solid Waste Minimisation in Shah Alam City, Malaysia". Environment-Behaviour Proceedings Journal 2, n.º 6 (6 de novembro de 2017): 53. http://dx.doi.org/10.21834/e-bpj.v2i6.989.

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Waste management is one of the most challenging problems. This study investigates the influence of household attributes on waste minimisation behaviour in Shah Alam City, Malaysia. Through a household survey, 300 respondents were randomly chosen. Findings from the study revealed that respondents behaviour has statistically significant associations with 4 socio-demographic, namely gender [F(298) = 7.33, p = 0.00]; race [F(2, 297) = 3.22, p = 0.04]; marital status [F(2, 297) = 3.51, p = 0.03]; home ownership [F(2, 295) = 7.57, p = 0.00]. The results of this analysis will facilitate the implementation of policies for sustainable solid waste minimisation.

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20

Dutta, J., V. Vetrivel e S. Nanda. "Semi-invex functions and their subdifferentials". Bulletin of the Australian Mathematical Society 56, n.º 3 (dezembro de 1997): 385–93. http://dx.doi.org/10.1017/s0004972700031166.

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We introduce the notion of semi-invex function (non-smooth) and the associated subdifferential. We study their properties and establish the conditions for optimality in constrained and unconstrained minimisation problems.

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Khrychev, Dmitry. "Optimal programmed control in energy minimisation problem". E3S Web of Conferences 458 (2023): 01028. http://dx.doi.org/10.1051/e3sconf/202345801028.

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This paper is devoted to the construction of optimal programmed control of the motion of a material point in a medium with a random coefficient of resistance in a homogeneous field of gravity of the Earth. The control objective is to minimise the mathematical expectation of the total mechanical energy of the material point. The problem is solved by two methods proposed by the author in previous works. Both methods assume approximation of the initial stochastic problem by deterministic optimal control problems. In the first case, the transition to approximate deterministic problems is carried out by replacing the parameters representing continuous random variables by discrete-type random variables converging in distribution to the original continuous ones (the method of distribution discretisation). The meaning of such a replacement is that the resulting approximate problem can be considered no longer as a stochastic, but as a deterministic optimal control problem, and can be solved, accordingly, with the help of known standard methods. In the second case, the initial stochastic dynamic system as a result of averaging its equations is replaced first by an infinite system and then, after zeroing all moments of sufficiently high order, by a finite system of equations for mixed moments of the solution and a random parameter (method of moments). The control functions and the optimal values of the quality functional obtained by the two methods were found to be almost identical, and both methods showed good convergence.

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Vaidya, Omkarprasad S., L. Ganapathy e Sushil Kumar. "A cost minimisation model for system reliability allocation". International Journal of Quality & Reliability Management 36, n.º 9 (7 de outubro de 2019): 1620–43. http://dx.doi.org/10.1108/ijqrm-07-2018-0199.

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Purpose The purpose of this paper is to consider a nonlinear problem of minimizing the cost of providing reliable systems. The authors assume that the system consists of several components in series, and for each such component, the cost of the component increases exponentially with its reliability. Design/methodology/approach In order to solve this nonlinear optimization problem, the authors propose two approaches. The first approach is based on the concept of adjusting the reliability of a pair of components to minimize the cost of the system. The authors call this procedure as reliability adjustment routine (RAR). Proofs of optimality and convergence for the proposed model are also provided. The second approach solves the problem by using a Lagrangian multiplier. A procedure is developed to obtain the maximum step size to achieve the desired optimal solution in minimum iterations. Proposed approaches are efficient and give exact solutions. Findings Proposed methods enable a decision maker to allocate reliability to the components in series while minimizing the total cost of the system. The developed procedures are illustrated using a numerical example. Although an exponential relationship between the component cost and reliability is assumed, this can be extended to various other nonlinear distributions. Originality/value This cost optimization problem, subject to system component reliability values, assumes the near practical nonlinear pattern of cost vs reliability. Such problems are complex to solve. The authors provide a unique approach called RAR to solve such convoluted problems. The authors also provide an approach to solve such problems by using a Lagrangian multiplier method. Various proofs have been worked out to substantiate the work.

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Motreanu, Dumitru. "A multiple linking minimax principle". Bulletin of the Australian Mathematical Society 53, n.º 1 (fevereiro de 1996): 39–49. http://dx.doi.org/10.1017/s0004972700016701.

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The aim of this paper is three-fold: to fill the gap between different deformation lemmas, to obtain a unifying minimax result where multiple linking situations can occur, and to locate the critical points as solutions of minimisation problems.

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Lord, Nick. "An unexpected appearance of e in a family of minimisation problems". Mathematical Gazette 104, n.º 561 (8 de outubro de 2020): 553–55. http://dx.doi.org/10.1017/mag.2020.121.

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Chittaro, Francesca C., e Laura Poggiolini. "Singular extremals in L1-optimal control problems: sufficient optimality conditions". ESAIM: Control, Optimisation and Calculus of Variations 26 (2020): 99. http://dx.doi.org/10.1051/cocv/2020023.

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In this paper we are concerned with generalised L1-minimisation problems, i.e. Bolza problems involving the absolute value of the control with a control-affine dynamics. We establish sufficient conditions for the strong local optimality of extremals given by the concatenation of bang, singular and inactive (zero) arcs. The sufficiency of such conditions is proved by means of Hamiltonian methods. As a by-product of the result, we provide an explicit invariant formula for the second variation along the singular arc.

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Vilventhan, Aneetha, VG Ram e S. Sugumaran. "Value stream mapping for identification and assessment of material waste in construction: A case study". Waste Management & Research 37, n.º 8 (19 de junho de 2019): 815–25. http://dx.doi.org/10.1177/0734242x19855429.

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Construction sites are plagued with numerous problems, such as improper planning and management, high amounts of waste generation and low awareness of waste reduction. Construction and demolition waste literature provides several best practises and prescriptive strategies that help minimise waste during construction. However, it lacks in the systematic identification and minimisation approach of all possibilities of waste. Therefore, studies focusing on principles and tools that help systematically analyse the inefficiencies of on-site processes leading to waste generation and philosophies addressing waste minimisation are necessary. As eliminating waste is one of the key lean principles, this article discusses the need and importance of integrating the lean construction with the construction and demolition waste management. This article aims to estimate and assess the causes of waste generation in a high-rise building construction through a case study in Chennai city (India) using value stream mapping, a key lean construction tool. Onsite monitoring and measurement were performed to quantify the amount of waste generated. A waste generation rate of 66.26 kg m−2 was identified, of which concrete, cement mortar and brick waste represented almost 90% of the total construction waste. Direct observation and interviews of site personnel were conducted to understand the causes of waste generation. A strategic framework has been proposed to improve construction and demolition waste minimisation depicting the synergy of combining lean construction principles with construction and demolition waste management strategies. The proposed framework helps in the systematic identification, assessment and minimisation of on-site construction waste generation.

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Adamson, Duncan, Argyrios Deligkas, Vladimir Gusev e Igor Potapov. "On the Hardness of Energy Minimisation for Crystal Structure Prediction*". Fundamenta Informaticae 184, n.º 3 (15 de fevereiro de 2022): 181–203. http://dx.doi.org/10.3233/fi-2021-2096.

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Crystal Structure Prediction (CSP) is one of the central and most challenging problems in materials science and computational chemistry. In CSP, the goal is to find a configuration of ions in 3D space that yields the lowest potential energy. Finding an efficient procedure to solve this complex optimisation question is a well known open problem. Due to the exponentially large search space, the problem has been referred in several materials-science papers as “NP-Hard and very challenging” without a formal proof. This paper fills a gap in the literature providing the first set of formally proven NP-Hardness results for a variant of CSP with various realistic constraints. In particular, we focus on the problem of removal: the goal is to find a substructure with minimal potential energy, by removing a subset of the ions. Our main contributions are NP-Hardness results for the CSP removal problem, new embeddings of combinatorial graph problems into geometrical settings, and a more systematic exploration of the energy function to reveal the complexity of CSP. In a wider context, our results contribute to the analysis of computational problems for weighted graphs embedded into the three-dimensional Euclidean space.

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Bisira, Hammed, e Abdellah Salhi. "Reshuffle minimisation to improve storage yard operations efficiency". Journal of Algorithms & Computational Technology 15 (janeiro de 2021): 174830262199401. http://dx.doi.org/10.1177/1748302621994010.

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There are many ways to measure the efficiency of the storage area management in container terminals. These include minimising the need for container reshuffle especially at the yard level. In this paper, we consider the container reshuffle problem for stacking and retrieving containers. The problem was represented as a binary integer programming model and solved exactly. However, the exact method was not able to return results for large instances. We therefore considered a heuristic approach. A number of heuristics were implemented and compared on static and dynamic reshuffle problems including four new heuristics introduced here. Since heuristics are known to be instance dependent, we proposed a compatibility test to evaluate how well they work when combined to solve a reshuffle problem. Computational results of our methods on realistic instances are reported to be competitive and satisfactory.

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Oeri, Hans, e David Goluskin. "Convex computation of maximal Lyapunov exponents". Nonlinearity 36, n.º 10 (1 de setembro de 2023): 5378–400. http://dx.doi.org/10.1088/1361-6544/acecf5.

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Abstract We describe an approach for finding upper bounds on an ODE dynamical system’s maximal Lyapunov exponent (LE) among all trajectories in a specified set. A minimisation problem is formulated whose infimum is equal to the maximal LE, provided that trajectories of interest remain in a compact set. The minimisation is over auxiliary functions that are defined on the state space and subject to a pointwise inequality. In the polynomial case—i.e. when the ODE’s right-hand side is polynomial, the set of interest can be specified by polynomial inequalities or equalities, and auxiliary functions are sought among polynomials—the minimisation can be relaxed into a computationally tractable polynomial optimisation problem subject to sum-of-squares constraints. Enlarging the spaces of polynomials over which auxiliary functions are sought yields optimisation problems of increasing computational cost whose infima converge from above to the maximal LE, at least when the set of interest is compact. For illustration, we carry out such polynomial optimisation computations for two chaotic examples: the Lorenz system and the Hénon–Heiles system. The computed upper bounds converge as polynomial degrees are raised, and in each example we obtain a bound that is sharp to at least five digits. This sharpness is confirmed by finding trajectories whose leading Lyapunov exponents approximately equal the upper bounds.

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Wu, Xiao, e Xianping Guo. "First Passage Optimality and Variance Minimisation of Markov Decision Processes with Varying Discount Factors". Journal of Applied Probability 52, n.º 2 (junho de 2015): 441–56. http://dx.doi.org/10.1239/jap/1437658608.

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This paper deals with the first passage optimality and variance minimisation problems of discrete-time Markov decision processes (MDPs) with varying discount factors and unbounded rewards/costs. First, under suitable conditions slightly weaker than those in the previous literature on the standard (infinite horizon) discounted MDPs, we establish the existence and characterisation of the first passage expected-optimal stationary policies. Second, to further distinguish the expected-optimal stationary policies, we introduce the variance minimisation problem, prove that it is equivalent to a new first passage optimality problem of MDPs, and, thus, show the existence of a variance-optimal policy that minimises the variance over the set of all first passage expected-optimal stationary policies. Finally, we use a computable example to illustrate our main results and also to show the difference between the first passage optimality here and the standard discount optimality of MDPs in the previous literature.

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Wu, Xiao, e Xianping Guo. "First Passage Optimality and Variance Minimisation of Markov Decision Processes with Varying Discount Factors". Journal of Applied Probability 52, n.º 02 (junho de 2015): 441–56. http://dx.doi.org/10.1017/s0021900200012560.

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This paper deals with the first passage optimality and variance minimisation problems of discrete-time Markov decision processes (MDPs) with varying discount factors and unbounded rewards/costs. First, under suitable conditions slightly weaker than those in the previous literature on the standard (infinite horizon) discounted MDPs, we establish the existence and characterisation of the first passage expected-optimal stationary policies. Second, to further distinguish the expected-optimal stationary policies, we introduce the variance minimisation problem, prove that it is equivalent to a new first passage optimality problem of MDPs, and, thus, show the existence of a variance-optimal policy that minimises the variance over the set of all first passage expected-optimal stationary policies. Finally, we use a computable example to illustrate our main results and also to show the difference between the first passage optimality here and the standard discount optimality of MDPs in the previous literature.

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Alva-Argáez, A., A. Vallianatos e A. Kokossis. "A multi-contaminant transhipment model for mass exchange networks and wastewater minimisation problems". Computers & Chemical Engineering 23, n.º 10 (dezembro de 1999): 1439–53. http://dx.doi.org/10.1016/s0098-1354(99)00303-8.

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Vo, Q. B., e N. Y. Foo. "Reasoning about Action: An Argumentation - Theoretic Approach". Journal of Artificial Intelligence Research 24 (1 de outubro de 2005): 465–518. http://dx.doi.org/10.1613/jair.1602.

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We present a uniform non-monotonic solution to the problems of reasoning about action on the basis of an argumentation-theoretic approach. Our theory is provably correct relative to a sensible minimisation policy introduced on top of a temporal propositional logic. Sophisticated problem domains can be formalised in our framework. As much attention of researchers in the field has been paid to the traditional and basic problems in reasoning about actions such as the frame, the qualification and the ramification problems, approaches to these problems within our formalisation lie at heart of the expositions presented in this paper.

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Jamal, Sameerah. "Imaging Noise Suppression: Fourth-Order Partial Differential Equations and Travelling Wave Solutions". Mathematics 8, n.º 11 (12 de novembro de 2020): 2019. http://dx.doi.org/10.3390/math8112019.

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In this paper, we discuss travelling wave solutions for image smoothing based on a fourth-order partial differential equation. One of the recurring issues of digital imaging is the amount of noise. One solution to this is to minimise the total variation norm of the image, thus giving rise to non-linear equations. We investigate the variational properties of the Lagrange functionals associated with these minimisation problems.

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Bounkhel, Messaoud. "Generalized Projections on Closed Nonconvex Sets in Uniformly Convex and Uniformly Smooth Banach Spaces". Journal of Function Spaces 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/478437.

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The present paper is devoted to the study of the generalized projectionπK:X∗→K, whereXis a uniformly convex and uniformly smooth Banach space andKis a nonempty closed (not necessarily convex) set inX. Our main result is the density of the pointsx∗∈X∗having unique generalized projection over nonempty close sets inX. Some minimisation principles are also established. An application to variational problems with nonconvex sets is presented.

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Andal C., Kothai, e Jayapal R. "Improved GA based power and cost management system in a grid-associated PV-wind system". International Journal of Power Electronics and Drive Systems (IJPEDS) 12, n.º 4 (1 de dezembro de 2021): 2531. http://dx.doi.org/10.11591/ijpeds.v12.i4.pp2531-2544.

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Renewable hybrids play an essential part in assisting India with quickening the decarbonisation of power production and lowering power production expense in the medium term. PV and wind energy are complementary to each other, making the system to generate electricity almost throughout the year. In this paper, a grid-associated PV-wind energy system tied with a battery is analysed. PV, wind, grid and battery are the sources to be effectively scheduled for uninterrupted power and cost minimisation. Energy management controllers use optimisation strategies for effective utilisation of sources and cost minimisation. The methodologies are detailed as optimisation problems. Limiting the household energy cost is considered as objective, and the delivery ratio of power offered to the grid and utilised locally is treated as the optimisation variable. In this paper, an improved genetic algorithm is proposed to solve the formulated nonlinear optimisation problems. The time-of-use tariff is becoming popular in India; therefore, this article analyses the improved genetic algorithm based intelligent power and cost management system under time-of-use tariff. Using MATLAB, the proposed approach's performance is presented with the comparative analysis of conventional self-made for self-consumed and rest for sale mode and genetic algorithm-based energy management controller.

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Mostaghim, Sanaz, Christoph Steup e Heiner Zille. "Multi-objective distance minimization problems – applications in technical systems". at - Automatisierungstechnik 66, n.º 11 (27 de novembro de 2018): 964–74. http://dx.doi.org/10.1515/auto-2018-0054.

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Abstract This article describes the Distance Minimisation Problem (DMP) from a metaheuristic optimisation point of view. The problem is motivated by real applications and can be used to test the performance of optimisation methods like Evolutionary Algorithms. After formally describing the problem and its extensions using different metrics or dynamics, we perform experiments with well-known metaheuristic methods to demonstrate the performance on various DMP instances. The results show that modern algorithms like NSGA-II and SMPSO can struggle with this kind of problem under certain conditions, especially when Manhattan distances are used. On the other hand, specialised methods like GRA lack diversity of solutions in some cases. This indicates that even modern and powerful metaheuristic algorithms need to be chosen with care and with the respective optimisation task in mind.

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Clark, Ed, Nikos Katzourakis e Boris Muha. "Vectorial variational problems in L ^∞ constrained by the Navier–Stokes equations*". Nonlinearity 35, n.º 1 (6 de dezembro de 2021): 470–91. http://dx.doi.org/10.1088/1361-6544/ac372a.

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Abstract We study a minimisation problem in L p and L ∞ for certain cost functionals, where the class of admissible mappings is constrained by the Navier–Stokes equations. Problems of this type are motivated by variational data assimilation for atmospheric flows arising in weather forecasting. Herein we establish the existence of PDE-constrained minimisers for all p, and also that L p minimisers converge to L ∞ minimisers as p → ∞. We further show that L p minimisers solve an Euler–Lagrange system. Finally, all special L ∞ minimisers constructed via approximation by L p minimisers are shown to solve a divergence PDE system involving measure coefficients, which is a divergence-form counterpart of the corresponding non-divergence Aronsson–Euler system.

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Ujang, Z., e C. Buckley. "Water and wastewater in developing countries: present reality and strategy for the future". Water Science and Technology 46, n.º 9 (1 de novembro de 2002): 1–9. http://dx.doi.org/10.2166/wst.2002.0192.

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This paper summarises the paper presentation sessions at the Conference, as well giving insights on the issues related to developing countries. It also discusses the present status of practice and research on water and wastewater management, and projected future scenario based not only on the papers presented in the Conference, but also on other sources. The strategy is presented to overcome many problems in developing countries such as rapid urbanization, industrialization, population growth, financial and institutional problems and, depleting water resources. The strategy consists of Integrated Urban Water Management (IUWM), cleaner industrial production, waste minimisation and financial arrangements.

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Evans, Ben James, Ben Smith, Sean Peter Walton, Neil Taylor, Martin Dodds e Vladeta Zmijanovic. "A Mesh-Based Approach for Computational Fluid Dynamics-Free Aerodynamic Optimisation of Complex Geometries Using Area Ruling". Aerospace 11, n.º 4 (11 de abril de 2024): 298. http://dx.doi.org/10.3390/aerospace11040298.

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In this paper, an optimisation procedure is introduced that uses a significantly cheaper, and CFD-free, objective function for aerodynamic optimisation than conventional CFD-driven approaches. Despite the reduced computational cost, we show that this approach can still drive the optimisation scheme towards a design with a similar reduction in drag coefficient for wave drag-dominated problems. The approach used is ‘CFD-free’, i.e., it does not require any computational aerodynamic analysis. It can be applied to geometries discretised using meshes more conventionally used for ‘standard’ CFD-based optimisation approaches. The approach outlined in this paper makes use of the transonic area rule and its supersonic extension, exploiting a mesh-based parameterisation and mesh morphing methodology. The paper addresses the following question: ‘To what extent can an optimiser perform (wave) drag minimisation if using ‘area ruling’ alone as the objective (fitness) function measurement?’. A summary of the wave drag approximation in transonic and supersonic regimes is outlined along with the methodology for exploiting this theory on a typical CFD surface mesh to construct an objective function evaluation for a given geometry. The implementation is presented including notes on the considerations required to ensure stability, and error minimisation, of the numerical scheme. The paper concludes with the results from a number of (simple and complex geometry) examples of a drag-minimisation optimisation study and the results are compared with an approach using full-fidelity CFD simulation. The overall conclusions from this study suggest that the approach presented is capable of driving a geometry towards a similar shape to when using full-fidelity CFD at a significantly lower computational cost. However, it cannot account for any constraints, driven by other aerodynamic factors, that might be present within the problem.

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Maroński, Ryszard. "Aeronautical Inspirations in Biomechanics". Polish Journal of Sport and Tourism 24, n.º 1 (28 de março de 2017): 5–9. http://dx.doi.org/10.1515/pjst-2017-0001.

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Abstract Introduction. The goal of the paper is to show that some problems formulated in the dynamics of atmospheric flight are very similar to the problems formulated in the biomechanics of motion and medicine. Three problems were compared: minimumheat transfer from the boundary layer to the ballistic missile skin, minimum-time ski descent, and the minimisation of the negative cumulated effect of the drug in cancer chemotherapy. Material and methods. All these problems are solved using the same method originally developed for aerospace systems - the method of Miele (the extremisation method of linear integrals via Green’s theorem). Results. It is shown that the problems arising in different branches of knowledge are very similar in problem formulations, mathematical models, and solution methods used. Conclusions. There are no barriers between different disciplines.

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Jiang, Daijun, Hui Feng e Jun Zou. "Quadratic convergence of Levenberg-Marquardt method for elliptic and parabolic inverse robin problems". ESAIM: Mathematical Modelling and Numerical Analysis 52, n.º 3 (maio de 2018): 1085–107. http://dx.doi.org/10.1051/m2an/2018016.

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We study the Levenberg-Marquardt (L-M) method for solving the highly nonlinear and ill-posed inverse problem of identifying the Robin coefficients in elliptic and parabolic systems. The L-M method transforms the Tikhonov regularized nonlinear non-convex minimizations into convex minimizations. And the quadratic convergence of the L-M method is rigorously established for the nonlinear elliptic and parabolic inverse problems for the first time, under a simple novel adaptive strategy for selecting regularization parameters during the L-M iteration. Then the surrogate functional approach is adopted to solve the strongly ill-conditioned convex minimizations, resulting in an explicit solution of the minimisation at each L-M iteration for both the elliptic and parabolic cases. Numerical experiments are provided to demonstrate the accuracy, efficiency and quadratic convergence of the methods.

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Le, Hoang Son, Rini Akmeliawati e Gustavo Carneiro. "Domain Generalisation with Domain Augmented Supervised Contrastive Learning (Student Abstract)". Proceedings of the AAAI Conference on Artificial Intelligence 35, n.º 18 (18 de maio de 2021): 15821–22. http://dx.doi.org/10.1609/aaai.v35i18.17907.

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Domain generalisation (DG) methods address the problem of domain shift, when there is a mismatch between the distributions of training and target domains. Data augmentation approaches have emerged as a promising alternative for DG. However, data augmentation alone is not sufficient to achieve lower generalisation errors. This project proposes a new method that combines data augmentation and domain distance minimisation to address the problems associated with data augmentation and provide a guarantee on the learning performance, under an existing framework. Empirically, our method outperforms baseline results on DG benchmarks.

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Sagan, Joanna, e Anna Sobotka. "Analysis of Factors Affecting the Circularity of Building Materials". Materials 14, n.º 23 (29 de novembro de 2021): 7296. http://dx.doi.org/10.3390/ma14237296.

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A circular economy requires closed circuits of consumed resources. Construction generates approximately 50% of solid waste globally, which is difficult to manage. The aim of this article was to identify the factors that determine the development of circular construction in the context of waste minimisation in the life cycle of building structures. The identification of cause-and-effect relationships by means of the DEMATEL method allows the problems of construction waste management to be taken into account in the context of the development of sustainable construction and fulfilling the principles of the circular economy.

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Alfaro, A., M. Doan, J. Finke, M. Galdes e M. Zohdy. "Application of Divide and Conquer Extended Genetic Algorithm to Tertiary Protein Structure of Chymotrypsin Inhibitor-2". Applied Bionics and Biomechanics 3, n.º 4 (2006): 263–71. http://dx.doi.org/10.1155/2006/841046.

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Determining the method by which a protein thermodynamically folds and unfolds in three-dimension is one of the most complex and least understood problems in modern biochemistry. Misfolded proteins have been recently linked to diseases including Amyotrophic Lateral Sclerosis and Alzheimer's disease. Because of the large number of parameters involved in defining the tertiary structure of proteins, based on free energy global minimisation, we have developed a new Divide and Conquer (DAC) Extended Genetic Algorithm. The approach was applied to explore and verify the energy landscape of protein chymotrypsin inhibitor-2.

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MH, Dr Karim, Seied Beniamin Hosseini, Dr Ayesha Farooq, Hossein (Adib) Arab e Ali Takroosta. "A Strategic Review on Economic Dispatch Distribution and Environmental Considerations". Restaurant Business 118, n.º 12 (6 de dezembro de 2019): 166–76. http://dx.doi.org/10.26643/rb.v118i12.13211.

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Power systems contain four generic parts, including production, transmission, dispatch distribution, and consumption. Generally, dispatch distribution between powerhouses modelled with the goal of minimisation in utilisation cost. However, Environmental concerns were given more attention to powerhouse emissions such as SO2, CO2 and NO cause to investigate modelling in recent researches. However consideration of the objectives of fuel cost and emission value in the dispatch distribution problems known as the eco-environmental dispatch distribution. Although Due to the paradox between the reduction of utility costs and external costs, different methods used.

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Avanzini, G., e G. de Matteis. "Optimal takeoff performance of a vectored thrust aircraft". Aeronautical Journal 99, n.º 987 (setembro de 1995): 275–81. http://dx.doi.org/10.1017/s0001924000028451.

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AbstractThe optimal takeoff performance of a vectored thrust V/Stol aircraft is analysed by a nonlinear programming method based on a sequential unconstrained minimisation technique. The study is focused on ship operations which involve VTO and ski-jump STO launches. Once the optimal ramp geometry is determined, minimum-fuel and minimum-time problems are solved. The optimal control sequences are evaluated and the effects of ship motion and atmospheric winds are discussed. A microburst encounter following an STO launch is also dealt with in terms of aircraft survival.

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Basupi, Innocent, Zoran Kapelan e David Butler. "Reducing life-cycle carbon footprints in the redesign of water distribution systems". Journal of Water and Climate Change 4, n.º 3 (18 de abril de 2013): 176–92. http://dx.doi.org/10.2166/wcc.2013.004.

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Water distribution systems (WDSs) contribute to undesirable greenhouse gas (GHG) emissions that are generated through their component fabrication, construction, operation and disposal processes. The concentration of GHGs in the atmosphere is strongly associated with global warming and climate change. In order to meet the consequent challenge of limiting GHG emissions, the problem of WDS redesign is formulated here as a multi-objective optimisation problem. The three objectives are as follows: (1) minimisation of total redesign cost, (2) maximisation of the WDS resilience, and (3) minimisation of GHG emissions. The resilience index serves as a measure of the WDS's intrinsic capability to ensure continuity of supply to users after sudden failure conditions, whilst the GHG emissions serve as a measure of environmental performance and climate change mitigation. The output from the non-dominated sorting genetic algorithm (NSGA2) optimisation process is a Pareto front containing optimal solutions traded-off in terms of the three objectives analysed. This methodology was applied on the New York Tunnels and the Anytown Network problems. The results obtained demonstrate that the redesign approach leads to cost-effective and resilient solutions that can also mitigate climate change compared with the single-objective (least cost) and other multi-objective redesigns over the long-term planning horizon.

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Tikhomirov, Dmitry, e Vladimir Plotnikov. "The minimisation of risks in project finance: approaches to financial modelling and structuring". MATEC Web of Conferences 193 (2018): 05069. http://dx.doi.org/10.1051/matecconf/201819305069.

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Complex investment projects require detailed and thorough analysis of numerous aspects and proper actions taken on all stages of their development. The article considers peculiarities of project finance, major risks of projects for the main participants, provides practical recommendations on approaches to project financial models, and brief review of recourse and debt service undertaking mechanism. The article is the result of practical experience and analysis of the problems of project finance based on implementation of the largest investment projects.

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CELANO, G., A. COSTA e S. FICHERA. "AN EVOLUTIONARY ALGORITHM FOR PURE FUZZY FLOWSHOP SCHEDULING PROBLEMS". International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems 11, n.º 06 (dezembro de 2003): 655–69. http://dx.doi.org/10.1142/s0218488503002466.

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The pure flowshop scheduling problem is here investigated from a perspective considering me uncertainty associated with the execution of shop floor activities. Being the flowshop problem is NP complete, a large number of heuristic algorithms have been proposed in literature to determine an optimal solution. Unfortunately, these algorithms usually assume a simplifying hypothesis: the problem data are assumed as deterministic, i.e. job processing times and the due dates are expressed through a unique value, which does not reflect the real process variability. For this reason, some authors have recently proposed the use of a fuzzy set theory to model the uncertainty in scheduling problems. In this paper, a proper genetic algorithm has been developed for solving the fuzzy flowshop scheduling problem. The optimisation involves two different objectives: the completion time minimisation and the due date fulfilment; both the single and multi-objective configurations have been considered. A new ranking criterion has been proposed and its performance has been tested through a set of test problems. A numerical analysis confirms the efficiency of the proposed optimisation procedure.

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