Search results for "Erk"
showing 10 items of 2599 documents
Solving continuous models with dependent uncertainty: a computational approach
2013
This paper presents a computational study on a quasi-Galerkin projection-based method to deal with a class of systems of random ordinary differential equations (r.o.d.e.'s) which is assumed to depend on a finite number of random variables (r.v.'s). This class of systems of r.o.d.e.'s appears in different areas, particularly in epidemiology modelling. In contrast with the other available Galerkin-based techniques, such as the generalized Polynomial Chaos, the proposed method expands the solution directly in terms of the random inputs rather than auxiliary r.v.'s. Theoretically, Galerkin projection-based methods take advantage of orthogonality with the aim of simplifying the involved computat…
Comparison of continuous and discontinuous Galerkin approaches for variable-viscosity Stokes flow
2015
We describe a Discontinuous Galerkin (DG) scheme for variable-viscosity Stokes flow which is a crucial aspect of many geophysical modelling applications and conduct numerical experiments with different elements comparing the DG approach to the standard Finite Element Method (FEM). We compare the divergence-conforming lowest-order Raviart-Thomas (RT0P0) and Brezzi-Douglas-Marini (BDM1P0) element in the DG scheme with the bilinear Q1P0 and biquadratic Q2P1 elements for velocity and their matching piecewise constant/linear elements for pressure in the standard continuous Galerkin (CG) scheme with respect to accuracy and memory usage in 2D benchmark setups. We find that for the chosen geodynami…
Seed Activation Scheduling for Influence Maximization in Social Networks
2018
This paper addresses the challenge of strategically maximizing the influence spread in a social network, by exploiting cascade propagators termed “seeds”. It introduces the Seed Activation Scheduling Problem (SASP) that chooses the timing of seed activation under a given budget, over a given time horizon, in the presence/absence of competition. The SASP is framed as a blogger-centric marketing problem on a two-level network, where the decisions are made to buy sponsored posts from prominent bloggers at calculated points in time. A Bayesian evidence diffusion model – the Partial Parallel Cascade (PPC) model – allows the network nodes to be partially activated, proportional to their accumulat…
Discrete Maximum Principle for Galerkin Finite Element Solutions to Parabolic Problems on Rectangular Meshes
2004
One of the most important problems in numerical simulation is the preservation of qualitative properties of solutions of mathematical models. For problems of parabolic type, one of such properties is the maximum principle. In [5], Fujii analyzed the discrete analogue of the (continuous) maximum principle for the linear parabolic problems, and derived sufficient conditions guaranteeing its validity for the Galerkin finite element approximations built on simplicial meshes. In our paper, we present the sufficient conditions for the validity of the discrete maximum principle for the case of bilinear finite element space approximations on rectangular meshes.
Solution strategies for 1D elastic continuum with long-range interactions: Smooth and fractional decay
2010
Abstract An elastic continuum model with long-range forces is addressed in this study within the context of approximate analytical methods. Such a model stems from a mechanically-based approach to non-local theory where long-range central forces are introduced between non-adjacent volume elements. Specifically, long-range forces depend on the relative displacement, on the volume product between interacting elements and they are proportional to a proper, material-dependent, distance-decaying function. Smooth-decay functions lead to integro-differential governing equations whereas hypersingular, fractional-decay functions lead to a fractional differential governing equation of Marchaud type. …
Direct stiffness matrices of BEs in the Galerkin BEM formulation
2001
Abstract In the analysis of an elastic two-dimensional solid body by means of the Symmetric Galerkin Boundary Element Method (SGBEM), difficulties arise in the computation of some terms of the solving system coefficients. In fact these coefficients are expressed as double integrals with singularities of order 1/ r 2 , r being the distance between the field and source points. In order to compute these coefficients a strategy based on Schwartz's distribution theory is employed. In this paper the direct stiffness matrix related to the generic node of the free boundary are computed in closed form.
A discontinuous Galerkin formulation for nonlinear analysis of multilayered shells refined theories
2023
A novel pure penalty discontinuous Galerkin method is proposed for the geometrically nonlinear analysis of multilayered composite plates and shells, modelled via high-order refined theories. The approach allows to build different two-dimensional equivalent single layer structural models, which are obtained by expressing the covariant components of the displacement field through-the-thickness via Taylor’s polynomial expansion of different order. The problem governing equations are deduced starting from the geometrically nonlinear principle of virtual displacements in a total Lagrangian formulation. They are addressed with a pure penalty discontinuous Galerkin method using Legendre polynomial…
Viihtymistä, kontakteja ja hyötyä : sähköiset mediat kuudesluokkalaisen silmin
2009
Media on nykypäivänä suuri ja alati kasvava osa elämäämme, ja lapset ja nuoret ovat sen käytössä edelläkävijöitä. Tämän tutkimuksen tarkoituksena olikin selvittää, minkälaisia merkityksiä sähköisillä medioilla (tietokone/internet, elektroniset pelit, televisio ja kännykkä) on yhden kuudennen luokan oppilaille. Tutkimuksessa tarkasteltiin myös, mitä sähköisiä medioita tutkimuksessa mukana olevat lapset käyttävät ja miten. Tutkimuksessa käytettiin menetelmien ja aineistojen triangulaatiota, jolloin tutkimuksessa yhdistyivät sekä laadullinen että määrällinen tutkimus. Käytettyjä tutkimusaineistoja olivat kyselylomakkeet, mediakirjoitelmat, päiväkirjat ja posterit. Kirjoitelmia ja postereita lä…
Teaching on Hybrid Courses : Insights from Commercial Online ICT-Training
2018
Information and communication technology (ICT) has evolved rapidly during the last decades. These technological advancements have enabled new ways of teaching and learning, such as online courses, where students attend training using their own computer equipment. Previous studies have shown that the student satisfaction and learning outcomes do not differ between the classroom and online students. However, our previous study conducted on hybrid courses, where part of the students was present in a classroom and part are participating online, revealed some issues related to teaching methods and technical difficulties. In this study, we researched how teachers of a commercial ICT-training orga…
Medicīnas māsas loma izglītošanā popularizējot pret tuberkulozes vakcīnu
2017
Bakalaura darba tēma – „Medicīnas māsas loma izglītošanā popularizējot pret tuberkulozes vakcīnu”. Tēmas aktualitāti nosaka tas, ka viens no galvenajiem iemesliem, jaundzimušā vakcinācijas atteikuma gadījumā, ir vecāku zināšanu trūkums par vakcīnu un vakcināciju kā tādu. Pētījuma darba mērķis - noskaidrot kāda ir medicīnas māsas loma izglītošanā popularizējot pret tuberkulozes vakcīnu. Mērķa sasniegšanai ir izvirzīti pētniecības uzdevumi - analizēt literatūru par medicīnas māsas lomu izglītošanā, pret tuberkulozes vakcīnu un analizēt D. Oremas pašaprūpes trūkuma teoriju, izmantojot to pētniecības darbā. Darbā tika izvirzīta hipotēze: Māsa, kā izglītotāja,veicina vecāku izpratni par pret tub…