Search results for "Abstract data type"

Algebrability of the set of hypercyclic vectors for backward shift operators

2020

Abstract We study the existence of algebras of hypercyclic vectors for weighted backward shifts on Frechet sequence spaces that are algebras when endowed with coordinatewise multiplication or with the Cauchy product. As a particular case, we obtain that the sets of hypercyclic vectors for Rolewicz's and MacLane's operators are algebrable.

Nature log-analytique du volume des sous-analytiques

2000

Using a preparation theorem for subanalytic functions and Lipschitz stratification for compact subanalytic sets we prove that volumes of slices of globally subanalytic sets and density have a log-analytic nature. We also prove that the set of parameters for which the volume of fiber is finite is globally subanalytic.

About Combining Metric Learning and Prototype Generation

2014

Distance metric learning has been a major research topic in recent times. Usually, the problem is formulated as finding a Mahalanobis-like metric matrix that satisfies a set of constraints as much as possible. Different ways to introduce these constraints and to effectively formulate and solve the optimization problem have been proposed. In this work, we start with one of these formulations that leads to a convex optimization problem and generalize it in order to increase the efficiency by appropriately selecting the set of constraints. Moreover, the original criterion is expressed in terms of a reduced set of representatives that is learnt together with the metric. This leads to further im…

Discrete-time static output-feedback semi-decentralized H<inf>∞</inf> controller design: An application to structural vibratio…

2012

In this work, we present a new and effective method to design discrete-time static output-feedback H ∞ controllers. This new method, based on a Linear Matrix Inequality (LMI) formulation, introduces a suitable transformation of the LMI variables that allows to obtain an explicit expression for the output-feedback gain matrix. Moreover, for problems involving a set of subsystems with information exchange constraints, a convenient structure on the LMI variables can be imposed in order to design semi-decentralized controllers, where the corresponding output-feedback gain matrix has a prescribed zero-nonzero structure. To illustrate the proposed methodology, discrete-time static velocity-feedba…

Approximation of Feasible Parameter Set in worst case identification of block-oriented nonlinear models

2003

Abstract The estimation of the Feasible Parameter Set for block-oriented nonlinear models in a worst case setting is considered. A bounding procedure is determined both for polytopic and ellipsoidie sets, consisting in the projection of the FPS ⊂ R MN of the extended parameter vector onto suitable M or N-dimensional subspaces and in the solution of convex optimization problems which provide the extreme points of the Parameter Uncertainties Intervals of the model parameteres. Bounds obtained are tighter then in the previous approaches.

Testing Independence: A New Approach

2000

In time series analysis and modelling, testing for independence allows us to determine if the estimated model is correctly specified. In this work, we present a very simple method to test for serial independence, based on the two-dimensional embedding vectors (the so-called “2-histories”), and we analyse the power and size of such a procedure against a wide set of linear and nonlinear alternatives.

Building Composite Indicators With Unweighted-TOPSIS

2023

Composite indicators have been widely used in a large number of fields, including innovation and entrepreneurship as a useful tool for conveying summary information about overall performance in a relatively simple way. The construction of composite indicators implies several stages concerning collection of data, selection of criteria and individual indicators, normalization and weighting of criteria and indicators, aggregation, and comparison of overall performance of the alternatives or options. This article aims at contributing to the construction of synthetic indicators by showing with a real example, how the proposed methodology can overcome the problem of the establisment of the decisi…

Not Another Set of Nuts and Bolts

2011

Cascades and multifilters

2000

Abstract Cascades (trees every element of which is a filter on the set of its successors), and multifilters, maps from cascades, are introduced. Multisequences constitute a special case of multifilters. Applications to convergence and to topology are indicated.

Toward solutions for energy efficiency

2020

Abstract The tariff setting for district heating (DH) services is a hard regulatory procedure. This chapter is devoted to development of the simple but sufficiently accurate methodology for fast and objective evaluation of the actual costs of DH to optimize the regulatory process and to set adequate tariffs on heat production and transmission. The developed methodology is based on the data sets of Latvian DH providers, but the methodological principles are applicable in another area too. Investigation of heat production drivers and following simulation revealed the key performance indicators (KPIs): fuel type and price. By usage of intelligent benchmarking data mining methods and mathematic…