Search results for " optimization"
showing 10 items of 2367 documents
Controlled polyhedral sweeping processes: existence, stability, and optimality conditions
2021
This paper is mainly devoted to the study of controlled sweeping processes with polyhedral moving sets in Hilbert spaces. Based on a detailed analysis of truncated Hausdorff distances between moving polyhedra, we derive new existence and uniqueness theorems for sweeping trajectories corresponding to various classes of control functions acting in moving sets. Then we establish quantitative stability results, which provide efficient estimates on the sweeping trajectory dependence on controls and initial values. Our final topic, accomplished in finite-dimensional state spaces, is deriving new necessary optimality and suboptimality conditions for sweeping control systems with endpoint constrain…
Formulations and exact algorithms for the distance-constrained generalized directed rural postman problem
2017
[EN] The generalized directed rural postman problem is an arc routing problem with many interesting real-life applications, such as routing for meter reading. In this application, a vehicle with a receiver travels through a series of neighborhoods. If the vehicle gets closer than a certain distance to a meter, the receiver is able to record the gas, water, or electricity consumption. Therefore, the vehicle does not need to traverse every street, but only a few, to get close enough to each meter. We study an extension of this problem in which a fleet of vehicles is available. Given the characteristics of the mentioned application, the vehicles have no capacities but there is a maximum distan…
Contributions to Close-Enough Arc Routing Problems
2021
A pesar de carecer de datos específicos, se estima que el sector del transporte representa aproximadamente el 64% del consumo mundial de combustible, el 27% del consumo total de energía y el 23% de las emisiones mundiales de dióxido de carbono (CO2) relacionadas con la energía. Además, se prevé que el impacto medioambiental del sector del transporte aumente de forma drástica en los próximos años debido al efecto de la globalización, que ha eliminado barreras haciendo posible la accesibilidad a todos los lugares, productos y servicios del mundo. Por ello, el transporte se sitúa como uno de los principales retos en materia de desarrollo, para impulsar la prosperidad y lograr así un entorno so…
Entry-Item-Quantity-ABC Analysis-Based Multitype Cigarette Fast Sorting System
2012
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2012/847591 Open access Numerous items, small order, and frequent delivery are the characteristics of many distribution centers. Such characteristics generally increase the operating costs of the distribution center. To remedy this problem, this study employs the Entry-Item-Quantity (EIQ) method to identify the characteristic of the cigarette distribution center and further analyzes the importance degree of customers and the frequently ordered products by means of EQ/EN/IQ-B/IK statistic charts. Based on these analyses as well as the total rep…
Firefly Algorithm for Structural Optimization Using ANSYS
2021
In the mid-1980s, several metaheuristic methods began to be developed for solving a very large class of computational problems with the aim of obtaining more robust and efficient procedures. Among them, many metaheuristic methods use bio-inspired intelligent algorithms. In recent years, these methods are becoming increasingly important and they can be used in various subject areas for solving complex problems. Firefly Algorithm is a nature-inspired optimization algorithm proposed by Yang to solve multimodal optimization problems. In particular, the method is inspired by the nature of fireflies to emit a light signal to attract other individuals of this species. In this work, a numerical stu…
Binding mode analysis of ABCA7 for the prediction of novel Alzheimer's disease therapeutics
2021
Graphical abstract
A heuristic algorithm for project scheduling with splitting allowed
1996
In this article, we analyze the precedence diagramming method, the only published algorithm for time-only project scheduling with activity splitting allowed. The criteria used in this method (forward and backward pass computations) for deciding when an activity has to be interrupted are shown to be invalid in some situations. We look into the causes of these failures and propose new formulae that always provide feasible solutions. The new algorithm has been tested on 240 randomly generated problems ranging up to 600 activities and 7,200 precedence relationships, resulting in an average deviation from optima of less than 1 percent.
A Bi-objective Optimization Study of an Acid-Base Flow Battery for High Efficiency and Improved Power Density
2022
Electrical energy storage is critical for a broader penetration of renewable energies with intermittent nature, such as solar and wind energy. The Acid/Base Flow Battery (AB-FB) is a unique, sustainable, and environmental-friendly storage technology with high electrolyte solution energy density. The method relies on reversible electrodialytic technologies using bipolar membranes to transform electrical energy into chemical energy related to pH gradients and vice versa. The charge phase is accomplished by using bipolar membrane electrodialysis, whereas the discharge phase is performed via bipolar membrane reverse electrodialysis. In a previous work, we developed an advanced multi-scale proce…
Active Learning for Monitoring Network Optimization
2012
Kernel-based active learning strategies were studied for the optimization of environmental monitoring networks. This chapter introduces the basic machine learning algorithms originated in the statistical learning theory of Vapnik (1998). Active learning is closer to an optimization done using sequential Gaussian simulations. The chapter presents the general ideas of statistical learning from data. It derives the basics of kernel-based support vector algorithms. The active learning framework is presented and machine learning extensions for active learning are described in the chapter. Kernel-based active learning strategies are tested on real case studies. The chapter explores the use of a c…
Integrated simulation and optimization models for tracking international fixed income indices
2001
Portfolio managers in the international fixed income markets must address jointly the interest rate risk in each market and the exchange rate volatility across markets. This paper develops integrated simulation and optimization models that address these issues in a common framework. Monte Carlo simulation procedures generate jointly scenarios of interest and exchange rates and, thereby, scenarios of holding period returns of the available securities. The portfolio manager’s risk tolerance is incorporated either through a utility function or a (modified) mean absolute deviation function. The optimization models prescribe asset allocation weights among the different markets and also resolve b…