Search results for "Vektori"

Vektoru rēķini

1942

Teōrētiskā mēchanika, 1. sējums: Kinemātika

1940

A Surrogate-assisted Reference Vector Guided Evolutionary Algorithm for Computationally Expensive Many-objective Optimization

2018

We propose a surrogate-assisted reference vector guided evolutionary algorithm for computationally expensive optimization problems with more than three objectives. The proposed algorithm is based on a recently developed evolutionary algorithm for many-objective optimization that relies on a set of adaptive reference vectors for selection. The proposed surrogateassisted evolutionary algorithm uses Kriging to approximate each objective function to reduce the computational cost. In managing the Kriging models, the algorithm focuses on the balance of diversity and convergence by making use of the uncertainty information in the approximated objective values given by the Kriging models, the distr…

Instruction-based clinical eye-tracking study on the visual interpretation of divergence : how do students look at vector field plots?

2018

Relating mathematical concepts to graphical representations is a challenging task for students. In this paper, we introduce two visual strategies to qualitatively interpret the divergence of graphical vector field representations. One strategy is based on the graphical interpretation of partial derivatives, while the other is based on the flux concept. We test the effectiveness of both strategies in an instruction-based eye-tracking study with N = 41 physics majors. We found that students’ performance improved when both strategies were introduced (74% correct) instead of only one strategy (64% correct), and students performed best when they were free to choose between the two strategies (88…

Dimension of self-affine sets for fixed translation vectors

2016

An affine iterated function system is a finite collection of affine invertible contractions and the invariant set associated to the mappings is called self-affine. In 1988, Falconer proved that, for given matrices, the Hausdorff dimension of the self-affine set is the affinity dimension for Lebesgue almost every translation vectors. Similar statement was proven by Jordan, Pollicott, and Simon in 2007 for the dimension of self-affine measures. In this article, we have an orthogonal approach. We introduce a class of self-affine systems in which, given translation vectors, we get the same results for Lebesgue almost all matrices. The proofs rely on Ledrappier-Young theory that was recently ver…

Conditional convex orders and measurable martingale couplings

2014

Strassen's classical martingale coupling theorem states that two real-valued random variables are ordered in the convex (resp.\ increasing convex) stochastic order if and only if they admit a martingale (resp.\ submartingale) coupling. By analyzing topological properties of spaces of probability measures equipped with a Wasserstein metric and applying a measurable selection theorem, we prove a conditional version of this result for real-valued random variables conditioned on a random element taking values in a general measurable space. We also provide an analogue of the conditional martingale coupling theorem in the language of probability kernels and illustrate how this result can be appli…

Influence functions and efficiencies of the canonical correlation and vector estimates based on scatter and shape matrices

2006

In this paper, the influence functions and limiting distributions of the canonical correlations and coefficients based on affine equivariant scatter matrices are developed for elliptically symmetric distributions. General formulas for limiting variances and covariances of the canonical correlations and canonical vectors based on scatter matrices are obtained. Also the use of the so-called shape matrices in canonical analysis is investigated. The scatter and shape matrices based on the affine equivariant Sign Covariance Matrix as well as the Tyler's shape matrix serve as examples. Their finite sample and limiting efficiencies are compared to those of the Minimum Covariance Determinant estima…

Rastra attēlu pārveidoš ana vektoru formā

2017

Rastra un vektoru grafikas pēc savas uzbūves ir ļoti atšķirīgas un nesalīdzināmas, taču analizējot to struktūru un izmantojot dažādas attēlu apstrādes metodes ir iesējama rastra attēlu pārveidošana vektoru formā. Bakalaura darbā tiek apskatīti algoritmi un metodes, ar kurām iespējama rastra attēla pārveidošana vektoru formā. Darbā tiek aprakstīts attēlu vektorizācijas process apskatot vairākus, pēc izmantotajām metodēm atšķirīgus, vektorizācijas algoritmus. Tiek salīdzināti automatizētas vektorizācijas procesā iegūti attēli un aprakstīta tam paredzētā programmatūra.

Regressiomenetelmiä viljapellon biomassan estimointiin ortokuvista ja digitaalisesta korkeusmallista

2012

Tutkielmassa esitellään käyttötarkoitus biomassan estimoinnille ja vertaillaan kolmea regressiomenetelmää, lineaarista regressiota, k:n lähimmän naapurin menetelmää sekä tukivektoriregressiota. Tutkielmassa esitellään myös aineisto ja aineistoon suoritetut muunnokset.

Liela apjoma datu kopu klasterēšanas algoritmi

2016

Mūsdienās, strauji pieaugot internetā pieejamajam informācijas apjomam, aktuāla tēma valodu tehnoloģiju jomā ir informācijas grupēšana (klasterēšana) pēc vienotiem principiem vieglākai informācijas uztveramībai un izkaisītas informācijas apjoma mazināšanai. Darbā "Liela apjoma datu kopu klasterēšanas algoritmi" teorētiskajā daļā izpētītas un apkopotas metodes dokumentu klasterēšanai ar mērķi atrast piemērotāko metodi vai metožu kopu daudzvalodu ziņu straumju klasterēšanai. Darbā arī pētītas un salīdzinātas dažādas klasterēšanas rezultāta novērtēšanas metrikas. Praktiskajā daļā izstrādāta un izvērtēta sistēma daudzvalodu ziņu straumju klasterēšanai, tā darbības rezultāti un turpmāki pētījuma…