Search results for "proof"
showing 7 items of 187 documents
A methodology for the control of the residual lifetimes of carbon fibre reinforced composite pressure vessels
2005
International audience; Pressure vessels must be periodically proof tested. Traditional techniques for metal vessels are inapplicable for composite vessels as the latter do not break by crack propagation so that the reasoning behind the traditional testing procedures is not appropriate. Damage accumulation leading to the degradation of a composite vessel is by fibre failure. Fibres show a wide distribution in strengths and loading a composite inevitably breaks some. The method which has been developed is supported by an analysis of delayed fibre failure due to the relaxation of the resin around fibre breaks. This provokes overloading of intact fibres neighbouring breaks. The time until a cr…
Stability of stochastic nonlinear systems with state-dependent switching
2013
In this paper, the problem of stability on stochastic systems with state-dependent switching is investigated. To analyze properties of the switched system by means of Itô’s formula and Dynkin’s formula, it is critical to show switching instants being stopping times. When the given active-region set can be replaced by its interior, the local solution of the switched system is constructed by defining a series of stopping times as switching instants, and the criteria on global existence and stability of solution are presented by Lyapunov approach. For the case where the active-region set can not be replaced by its interior, the switched systems do not necessarily have solutions, thereby quasi-…
La aplicación del derecho extranjero en iberoamérica y la unión europea: : paralelismos desde la diferencia
2021
The potential application of a foreign law constitutes the logical outcome of any Private International Law? system. However, and despite its relevance, this issue lacks a common answer in the EU. In contrast to this, the analysis of the solutions drafted in Latin America as regards this issue grants a novel dimension to the European situation on this issue as well as highlights a meritorious reality that shows a high and very relevant degree of harmonization
Students' problems in the identification of subspaces in Linear Algebra
2018
International audience; The goal of the study presented in this paper is the investigation of students' problems with exercises concerning central topics of linear algebra courses at university level. We present the results of our analysis of students' work on an exercise about subspaces of . We evaluated the written solutions of the task as well as transcripts based on videos taken of student groups working on the problem. We identified and classified descriptions of vector spaces and subspaces that varied widely and demonstrated highly different skills in working with geometric or formal algebraic objects. We analyzed how far students could progress in a complex reasoning process, and ide…
Teaching and Learning of Geometry as a process of Objectification: conditions and obstacles to argumentation and proof. The role of natural language,…
2021
This paper examines some examples (taken from research conducted over the years) that show students’ linguistic attitudes in geometry tasks. The examples are framed within the Theory of Objectification with reference to the notion of sensuous cognition, semiotic means of objectification and levels of generality. We show the struggle students live, at higher levels of generality, in intertwining natural language, specific language and the spontaneous use of geometrical figures, bound to perception and kinaesthetic activity. Within the networking paradigm, we coordinate the Theory of Objectification and Duval’s semio-cognitive approach to frame the interplay between the ideal and the material…
Būtisks kaitējums. Teorija un prakse
2015
Izvēlētā bakalaura temats ir „Būtisks kaitējums. Teorija un prakse”. Temata izvēle nav nejauša, jo kopš Krimināllikuma spēkā stāšanās brīža, neskatoties uz virkni pieņemtajiem grozījumiem būtiska kaitējuma jēdziena satura konkretizēšanā un tiesu prakses pilnveidošanā, joprojām ir konstatējamas problēmas saistībā ar būtiska kaitējuma jēdziena satura atšķirīgo izpratni, konstatēšanu un pierādīšanu izmeklēšanas iestādē, prokuratūrā un tiesā. Bakalaura darba mērķis un uzdevums pilnvērtīgāk izprast kaitīgo seku – būtiska kaitējuma jēdziena saturu, tā attīstību caur Latvijas teritorijā vēsturiski spēkā esošajiem krimināllikumiem. Tostarp, arī sniegt ieskatu par būtiska kaitējuma esamību Igaunijas…
On the Amount of Nonconstructivity in Learning Recursive Functions
2011
Nonconstructive proofs are a powerful mechanism in mathematics. Furthermore, nonconstructive computations by various types of machines and automata have been considered by e.g., Karp and Lipton [17] and Freivalds [11]. They allow to regard more complicated algorithms from the viewpoint of much more primitive computational devices. The amount of nonconstructivity is a quantitative characterization of the distance between types of computational devices with respect to solving a specific problem. In the present paper, the amount of nonconstructivity in learning of recursive functions is studied. Different learning types are compared with respect to the amount of nonconstructivity needed to lea…