1,721,004 research outputs found
Polynomial programming prevents aircraft (and other) conflicts
No full textUsing a known algebraic result, we obtain a finite polynomial programming reformulation of a semi-infinite program modeling the aircraft deconfliction problem via subliminal speed regulation. Solving the reformulation yields better results than the state of the art for most of the tested instances
Espressioni numeriche ed espressioni letterali: continuità o rottura
No full textAbstract. Si analizza il rapporto tra calcolo letterale e calcolo di espressioni numeriche, evidenziando continuità e rotture . Si riporta poi alcuni risultati tratti da una sperimentazione svolta a livello del primo anno della scuola secondaria superiore
L’algebrista : un micromonde pour l’enseignementet l’apprentissage de l’algèbre de calcul
No full textRESUMÉ. Cet article présente un micromonde qui a été expérimenté en classe. Suite à des recherches que nous avions menées pour étudier le rôle du micromonde Cabri dans l’introduction de la géométrie en tant que domaine théorique, nous avons développé un
nouveau projet de recherche dans le contexte de l’algèbre. Nous présentons les principales caractéristiques du projet et décrivons le micromonde que nous avons conçu et son fonctionnement. Nous décrivons brièvement une expérimentation et nous discutons cette
expérience d’enseignement sur quelques exemples tirés de protocoles d’utilisation par les élève
On aircraft deconfliction by bilevel programming
No full textWe present a bilevel programming formulation for the aircraft deconfliction problem with multiple lower-level subproblems. We propose two reformulation based on the KKT conditions and the dual of the lower-level subproblems. Finally, we compare the results obtained implementing these formulations using global optimization solvers
Funzionalità didattiche: uno strumento operativo per progettare ed analizzare esperienze di laboratorio
No full text
Aircraft Conflict Resolution: A Benchmark Generator
Full text linkAircraft conflict resolution is one of the major tasks of computer-aided air traffic management and represents a challenging optimization problem. Many models and methods have been proposed to assist trajectory regulation to avoid conflicts. However, the question of testing the different mathematical optimization approaches against each other is still open. Standard benchmarks include unrealistic scenarios in which all the flights move toward a common point or completely random generated instances. There is a lack of a common set of test instances that allows comparison of the available methods under a variety of heterogeneous and representative scenarios. We present a flight deconfliction benchmark generator that allows the user to choose between (i) different predefined scenario inspired by existing benchmarks in the literature; (ii) pseudo-random traffic meeting certain congestion measurements; (iii) and randomly generated traffic. The proposed setting can account for different levels of difficulty in the deconfliction of the aircraft and allows to explore and compare the real limitations of optimization approaches for aircraft conflict resolution
Building theories: working in a microworld and writing the mathematical notebook
No full textAbstract. In the framework of a long term teaching experiment we present an educational approach based on the use of a dynamic geometry software and a symbolic manipulator. Here we present the general ideas of the followed approach focusing on how meanings can originate from phenomenological experience and evolve under the guidance of the teacher. In particular we will focus on meanings related to the ideas of theory, axiom and theore
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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