Search results for "a priori"
showing 10 items of 136 documents
Effective Handling of Dynamic Time Windows and Its Application to Solving the Dial-a-Ride Problem
2015
A dynamic time window relates to two operations that must be executed within a given time meaning that the difference between the points in time when the two operations are performed is bounded from above. The most prevalent context of dynamic time windows is when precedence is given for the two operations so that it is a priori specified that one operation must take place before the other. A prominent vehicle routing problem with dynamic time windows and precedence is the dial-a-ride problem (DARP), where user-specified transportation requests from origin to destination points must be serviced. The paper presents a new branch-and-cut-and-price solution approach for the DARP, the prototypi…
Dealing with preference uncertainty in contingent willingness to pay for a nature protection program: A new approach
2013
In this paper, we propose an alternative preference uncertainty measurement approach where respondents have the option to indicate their willingness to pay (WTP) for a nature protection program either as exact values or intervals from a payment card, depending on whether they are uncertain about their valuation. On the basis of their responses, we then estimate their degree of uncertainty. New within this study is that the respondent's degree of uncertainty is "revealed", while it is "stated" in those using existing measurement methods. Three statistical models are used to explore the sources of respondent uncertainty. We also present a simple way of calculating the uncertainty adjusted mea…
Multiple solutions for quasilinear elliptic problems via critical points in open sublevels and truncation principles
2012
Abstract We study a quasilinear elliptic problem depending on a parameter λ of the form − Δ p u = λ f ( u ) in Ω , u = 0 on ∂ Ω . We present a novel variational approach that allows us to obtain multiplicity, regularity and a priori estimate of solutions by assuming certain growth and sign conditions on f prescribed only near zero. More precisely, we describe an interval of parameters λ for which the problem under consideration admits at least three nontrivial solutions: two extremal constant-sign solutions and one sign-changing solution. Our approach is based on an abstract localization principle of critical points of functionals of the form E = Φ − λ Ψ on open sublevels Φ − 1 ( ] − ∞ , …
Nonlinearities and Adaptation of Color Vision from Sequential Principal Curves Analysis
2016
Mechanisms of human color vision are characterized by two phenomenological aspects: the system is nonlinear and adaptive to changing environments. Conventional attempts to derive these features from statistics use separate arguments for each aspect. The few statistical explanations that do consider both phenomena simultaneously follow parametric formulations based on empirical models. Therefore, it may be argued that the behavior does not come directly from the color statistics but from the convenient functional form adopted. In addition, many times the whole statistical analysis is based on simplified databases that disregard relevant physical effects in the input signal, as, for instance…
Heretical Mutiple Importance Sampling
2016
Multiple Importance Sampling (MIS) methods approximate moments of complicated distributions by drawing samples from a set of proposal distributions. Several ways to compute the importance weights assigned to each sample have been recently proposed, with the so-called deterministic mixture (DM) weights providing the best performance in terms of variance, at the expense of an increase in the computational cost. A recent work has shown that it is possible to achieve a trade-off between variance reduction and computational effort by performing an a priori random clustering of the proposals (partial DM algorithm). In this paper, we propose a novel "heretical" MIS framework, where the clustering …
Modelling by Statistic in Research of Mathematics Education
2008
Summary. The aim of this paper is to study the quantitative tools of the research in didactics. We want to investigate the theoretical-experimental relationships between factorial and implicative analysis. This chapter consists of three parts. The first one deals with the didactic research and some fundamental tools: the a priori analysis of a didactic situation, the collection of experimental data and the statistic analysis of data. The purpose of the second and the third section is to introduce the experimental comparison between the factorial and the implicative analysis in two researches in mathematics education.
Agreement on the Choice of Non-applicable Law or Law not in Accordance with Article 22(1) of the Twin Regulations: what Consequences for the Couple’s…
2021
Los Reglamentos (UE) 2016/1103 y 2016/1104 del Consejo autorizan a las parejas transfronterizas a elegir la ley aplicable a sus relaciones patrimoniales sobre la base de uno de los criterios enumerados en el artículo 22.1. Sin embargo, el acuerdo de elección de la ley puede tener un contenido diferente al señalado en la redacción del artículo 22 de los ?Reglamentos Gemelos?. El objetivo del análisis es ilustrar que sería incorrecto sostener que tales acuerdos son, a priori, inválidos o no permiten la autonomía de la voluntad. Esta cuestión requiere una evaluación de la finalidad concreta del acuerdo de las partes y debería, al menos, estar abierta al examen del tribunal competente.
Normatīvo aktu preventīvās konstitucionālās kontroles teorētiskie un praktiskie aspekti
2020
Maģistra darba teorētiskajā daļā ir analizēts preventīvās konstitucionālās kontroles jēdziens un tā raksturīgākās pazīmes, īpašu uzmanību veltot ilggadējā Francijas konstitucionālās kontroles modeļa analīzei. Vienlaikus ir vērtēti būtiskākie tiesību doktrīnā minētie preventīvās konstitucionālās kontroles pretargumenti, meklējot efektīvāko veidu tās īstenošanā. Praktiskajā daļā ir aplūkota preventīvās konstitucionālās kontroles izpausme un darbība Eiropā, labākos risinājumus attiecinot uz Latvijas konstitucionālās kontroles iespējamo pilnveidi. Autora ieskatā, pretēji tiesību doktrīnā paustajiem viedokļiem, korekti implementēta, preventīvā konstitucionālā kontrole var kalpot par veiksmīgu ri…
Exploring Multiobjective Optimization for Multiview Clustering
2018
We present a new multiview clustering approach based on multiobjective optimization. In contrast to existing clustering algorithms based on multiobjective optimization, it is generally applicable to data represented by two or more views and does not require specifying the number of clusters a priori . The approach builds upon the search capability of a multiobjective simulated annealing based technique, AMOSA, as the underlying optimization technique. In the first version of the proposed approach, an internal cluster validity index is used to assess the quality of different partitionings obtained using different views. A new way of checking the compatibility of these different partitioning…
Localized forms of the LBB condition and a posteriori estimates for incompressible media problems
2018
Abstract The inf–sup (or LBB) condition plays a crucial role in analysis of viscous flow problems and other problems related to incompressible media. In this paper, we deduce localized forms of this condition that contain a collection of local constants associated with subdomains instead of one global constant for the whole domain. Localized forms of the LBB inequality imply estimates of the distance to the set of divergence free fields. We use them and deduce fully computable bounds of the distance between approximate and exact solutions of boundary value problems arising in the theory of viscous incompressible fluids. The estimates are valid for approximations, which satisfy the incompres…