Search results for "ongelma"
showing 10 items of 549 documents
Linssit ohjelmoinnissa
2016
Ohjelmoinnissa on usein tilanteita, joissa kaksi toisiinsa yhteyksissä olevaa rakennetta on sidoksissa toisiinsa niin, että muutokset yhteen rakenteeseen heijastuvat asianmukaisesti myös toiseen rakenteeseen. Tässä tutkielmassa käsitellään datamallien välistä transformointia kaksisuuntaisten transformaatioiden näkökulmasta. Tekstissä käydään läpi erityisen tarkasti eräs kaksisuuntainen transformaatio, nimeltään linssit, ja tutkitaan linssien rakenteita ja ominaisuuksia. Linssien yhteydessä käydään läpi alunperin relaatiotietokannoista tullut termi näkymänpäivitysongelma, joka on yleistettävissä datamallien välisiin transformaatioihin. Linssit ovat vielä tällä hetkellä melko harvinaisia ohje…
Building up an ecologically sustainable and socially desirable post-COVID-19 future
2021
AbstractCOVID-19 crisis has emphasized how poorly prepared humanity is to cope with global disasters. However, this crisis also offers a unique opportunity to move towards a more sustainable and equitable future. Here, we identify the underlying environmental, social, and economic chronic causes of the COVID-19 crisis. We argue in favour of a holistic view to initiate a socio-economic transition to improve the prospects for global sustainability and human well-being. Alternative approaches to “Business-As-Usual” for guiding the transition are already available for implementation. Yet, to ensure a successful and just transition, we need to change our priorities towards environmental integrit…
Loneliness: A Social Problem by Keming Yang (2019)
2021
Äärellisyysfilosofia kaappaa Kantin?
2021
Monotonicity and local uniqueness for the Helmholtz equation
2017
This work extends monotonicity-based methods in inverse problems to the case of the Helmholtz (or stationary Schr\"odinger) equation $(\Delta + k^2 q) u = 0$ in a bounded domain for fixed non-resonance frequency $k>0$ and real-valued scattering coefficient function $q$. We show a monotonicity relation between the scattering coefficient $q$ and the local Neumann-Dirichlet operator that holds up to finitely many eigenvalues. Combining this with the method of localized potentials, or Runge approximation, adapted to the case where finitely many constraints are present, we derive a constructive monotonicity-based characterization of scatterers from partial boundary data. We also obtain the local…
Dimension bounds in monotonicity methods for the Helmholtz equation
2019
The article [B. Harrach, V. Pohjola, and M. Salo, Anal. PDE] established a monotonicity inequality for the Helmholtz equation and presented applications to shape detection and local uniqueness in inverse boundary problems. The monotonicity inequality states that if two scattering coefficients satisfy $q_1 \leq q_2$, then the corresponding Neumann-to-Dirichlet operators satisfy $\Lambda(q_1) \leq \Lambda(q_2)$ up to a finite-dimensional subspace. Here we improve the bounds for the dimension of this space. In particular, if $q_1$ and $q_2$ have the same number of positive Neumann eigenvalues, then the finite-dimensional space is trivial. peerReviewed
Ikääntyvien kokemat ongelmat Internetin käytössä
2006
Online Communities and Gambling Behaviors : a Systematic Review
2022
Abstract Purpose of Review The internet and virtual environments have enabled the formation of online communities around a variety of interests. Online communities focused on gambling are increasingly popular and attract users to interact and share ideas and experiences with likeminded others. This study reviews evidence from the latest research examining the role of online communities in gambling behaviors and gambling problems. Recent Findings A systematic literature search resulted in 17 studies. Research shows that online communities are used for diverse reasons like discussing gambling experiences and problems, sharing tips, and celebrating winnings with others. These reasons of online…
Partial data inverse problems for Maxwell equations via Carleman estimates
2015
In this article we consider an inverse boundary value problem for the time-harmonic Maxwell equations. We show that the electromagnetic material parameters are determined by boundary measurements where part of the boundary data is measured on a possibly very small set. This is an extension of earlier scalar results of Bukhgeim-Uhlmann and Kenig-Sj\"ostrand-Uhlmann to the Maxwell system. The main contribution is to show that the Carleman estimate approach to scalar partial data inverse problems introduced in those works can be carried over to the Maxwell system.
Linearized Calderón problem and exponentially accurate quasimodes for analytic manifolds
2022
In this article we study the linearized anisotropic Calderon problem on a compact Riemannian manifold with boundary. This problem amounts to showing that products of pairs of harmonic functions of the manifold form a complete set. We assume that the manifold is transversally anisotropic and that the transversal manifold is real analytic and satisfies a geometric condition related to the geometry of pairs of intersecting geodesics. In this case, we solve the linearized anisotropic Calderon problem. The geometric condition does not involve the injectivity of the geodesic X-ray transform. Crucial ingredients in the proof of our result are the construction of Gaussian beam quasimodes on the tra…