Search results for "optimality"
showing 10 items of 60 documents
On parsing optimality for dictionary-based text compression—the Zip case
2013
Dictionary-based compression schemes are the most commonly used data compression schemes since they appeared in the foundational paper of Ziv and Lempel in 1977, and generally referred to as LZ77. Their work is the base of Zip, gZip, 7-Zip and many other compression software utilities. Some of these compression schemes use variants of the greedy approach to parse the text into dictionary phrases; others have left the greedy approach to improve the compression ratio. Recently, two bit-optimal parsing algorithms have been presented filling the gap between theory and best practice. We present a survey on the parsing problem for dictionary-based text compression, identifying noticeable results …
Existence and Optimality of Nash Equilibria in Inventory Games
2005
Abstract This paper studies the stability and optimality of a distributed consensus protocol for n -player repeated non cooperative games under incomplete information. At each stage, the players choose binary strategies and incur in a payoff monotonically decreasing with the number of active players. The game is specialized to an inventory application, where fixed costs are shared among all retailers, interested in whether reordering or not from a common warehouse. The authors focus on Pareto optimality as a measure of coordination of reordering strategies, proving that there exists a unique Pareto optimal Nash equilibrium that verifies certain stability conditions.
An overview of semi-infinite programming theory and related topics through a generalization of the alternative theorems
1984
We propose new alternative theorems for convex infinite systems which constitute the generalization of the corresponding toGale, Farkas, Gordan andMotzkin. By means of these powerful results we establish new approaches to the Theory of Infinite Linear Inequality Systems, Perfect Duality, Semi-infinite Games and Optimality Theory for non-differentiable convex Semi-Infinite Programming Problem.
Méthodes géometriques en mécanique spatiale et aspects numériques
2005
We present in this thesis two research projectson the optimal control of the space vehicles.In the first, we have dealt with the orbit transferproblem. We study the minimum time control of a satellite that we want to reach a geostationary orbit. Our contribution is of two kinds. Geometric, first, since we study the controllability of the system together with the geometry of the transfer (structure of the command) by means of geometric control without state constraint tools (minimum principle). Then we present shootingalgorithm and homotopy method. These approaches allow the numerical resolution of problems with strong or low thrust satellites.The second project concerns to the calculation o…
Optimality results in orbit transfer
2007
Abstract The objective of this Note is to present optimality results in orbital transfer. Averaging of the energy minimization problem is considered, and properties of the associated Riemannian metric are discussed. To cite this article: B. Bonnard, J.-B. Caillau, C. R. Acad. Sci. Paris, Ser. I 345 (2007).
A data-driven surrogate-assisted evolutionary algorithm applied to a many-objective blast furnace optimization problem
2017
A new data-driven reference vector-guided evolutionary algorithm has been successfully implemented to construct surrogate models for various objectives pertinent to an industrial blast furnace. A total of eight objectives have been modeled using the operational data of the furnace using 12 process variables identified through a principal component analysis and optimized simultaneously. The capability of this algorithm to handle a large number of objectives, which has been lacking earlier, results in a more efficient setting of the operational parameters of the furnace, leading to a precisely optimized hot metal production process. peerReviewed
Tra continuo e discreto. Recenti tendenze nella linguistica contemporanea
2002
This paper investigates the relationship between continuum and discretum within recent theoretical approaches in contemporary linguistics, focusing in particular on the interaction with epistemological and methodological aspects common to physical-mathematical theoretical models
Why Use Interactive Multi-Objective Optimization in Chemical Process Design?
2008
Problems in chemical engineering, like most real-world optimization problems, typically, have several conflicting performance criteria or objectives and they often are computationally demanding, which sets special requirements on the optimization methods used. In this chapter, we point out some shortcomings of some widely used basic methods of multi-objective optimization. As an alternative, we suggest using interactive approaches where the role of a decision maker or a designer is emphasized. Interactive multi-objective optimization has been shown to suit well for chemical process design problems because it takes the preferences of the decision maker into account in an iterative manner tha…
Bilevel heat exchanger network synthesis with an interactive multi-objective optimization method
2012
Abstract Heat exchanger network synthesis (HENS) has been an active research area for more than 40 years because well-designed heat exchanger networks enable heat recovery in process industries in an energy- and cost-efficient manner. Due to ever increasing global competition and need to decrease the harmful effects done on the environment, there still is a continuous need to improve the heat exchanger networks and their synthesizing methods. In this work we present a HENS method that combines an interactive multi-objective optimization method with a simultaneous bilevel HENS method, where the bilevel part of the method is based on grouping of process streams and building aggregate streams …
Kaksivuotiaiden lasten fonologisen kehityksen variaatio : puheen ymmärrettävyyden sekä sananmuotojen tavoittelun ja tuottamisen tarkastelu
2007
Torvelainen selvitti kaksivuotiaiden lasten fonologisen eli äänteellisen kehityksen variaatiota. Edistyneimmät kaksivuotiaat puhuivat lähes aikuismallisesti, kun taas heikoimpien lasten puhe poikkesi vielä suuresti aikuismallista. – Äänteellistä kehitystä tutkittaessa pitää ottaa huomioon lapsen sanavarasto. Jos kaksivuotiaalla on pieni sanasto, on normaalia, että hänen puheensa poikkeaa vielä paljon aikuismallisesta puheesta. Suuri sanavarasto puolestaan liittyi hyvin aikuismaiseen kieleen, Päivi Torvelainen kertoo.Edistyneimpien kaksivuotiaiden tuottamat sanat olivat niin aikuissanojen kaltaisia, että heidän puheestaan lasta tuntematon aikuinen ymmärsi lähes kaiken (96 %), kun taas heikoi…