Search results for "Complexity"

Regression Wavelet Analysis for Lossless Coding of Remote-Sensing Data

2016

A novel wavelet-based scheme to increase coefficient independence in hyperspectral images is introduced for lossless coding. The proposed regression wavelet analysis (RWA) uses multivariate regression to exploit the relationships among wavelet-transformed components. It builds on our previous nonlinear schemes that estimate each coefficient from neighbor coefficients. Specifically, RWA performs a pyramidal estimation in the wavelet domain, thus reducing the statistical relations in the residuals and the energy of the representation compared to existing wavelet-based schemes. We propose three regression models to address the issues concerning estimation accuracy, component scalability, and c…

A Mesh-free Particle Method for Transient Full-wave Simulation

2007

A mesh-free particle method is presented for electromagnetic (EM) transient simulation. The basic idea is to obtain numerical solutions for the partial differential equations describing the EM problem in time domain, by using a set of particles, considered as spatial interpolation points of the field variables, arbitrarily placed in the problem domain and by avoiding the use of a regular mesh. Irregular problems geometry with diffused non-homogeneous media can be modeled only with an initial set of arbitrarily distributed particles. The time dependence is accounted for with an explicit finite difference scheme. Moreover the particle discretization can be improved during the process time ste…

Ultracentrifugation studies on the native form of the first component of human complement (C1)

1976

Impulsively-controlled systems and reverse dwell time: A linear programming approach

2015

We present a receding horizon algorithm that converges to the exact solution in polynomial time for a class of optimal impulse control problems with uniformly distributed impulse instants and governed by so-called reverse dwell time conditions. The cost has two separate terms, one depending on time and the second monotonically decreasing on the state norm. The obtained results have both theoretical and practical relevance. From a theoretical perspective we prove certain geometrical properties of the discrete set of feasible solutions. From a practical standpoint, such properties reduce the computational burden and speed up the search for the optimum thus making the algorithm suitable for th…

On the metric properties of dynamic time warping

1987

Recently, some new and promising methods have been proposed to reduce the number of Dynamic Time Warping (DTW) computations in Isolated Word Recognition. For these methods to be properly applicable, the verification of the Triangle Inequality (TI) by the DTW-based Dissimilarity Measure utilized seems to be an important prerequisite.

On the use of a metric-space search algorithm (AESA) for fast DTW-based recognition of isolated words

1988

The approximating and eliminating search algorithm (AESA) presented was recently introduced for finding nearest neighbors in metric spaces. Although the AESA was originally developed for reducing the time complexity of dynamic time-warping isolated word recognition (DTW-IWR), only rather limited experiments had been previously carried out to check its performance in this task. A set of experiments aimed at filling this gap is reported. The main results show that the important features reflected in previous simulation experiments are also true for real speech samples. With single-speaker dictionaries of up to 200 words, and for most of the different speech parameterizations, local metrics, a…

The Role of Contextual Factors in the Influence of ICT on Street-Level Discretion

2017

Public service workers in the frontline have traditionally enjoyed a wide freedom to make decisions during policy implementation. Research shows that technology has both constraining and enabling effects on public service workers affecting their ability to exercise discretion. What remains unclear is under which circumstances discretion is influenced by technology. Using a case study approach and drawing on neo-institutional theory, this paper studies a court to identify contextual factors affecting the phenomenon. Findings show that technology has no unilateral effect on street-level discretion, and is found moderated by contextual factors such as the degree of social complexity in a case,…

Employees' work patterns-office type fit and the dynamic relationship between flow and performance

2021

Organizations must improve their employees’ performance in order to compete effectively. Evidence shows that flow experiences enhance performance. However, a dynamic approach to this phenomenon is needed. Furthermore, different work patterns (based on task profiles) can have specific environmental requirements (office types). This research aims to analyze the dynamic relationship between office workers’ flow and in‐role and extra‐role performance, considering work pattern–office type fit as a predictor of the initial level of each of these three variables. A total of 83 workers participated in this diary study. Results of the latent growth model showed a positive association between: (1) th…

Smithian Growth and Complexity

2016

In this paper we argue that Adam Smith’s theory of division and labor and economic growth, in particular through the developments of Alfred Marshall, Allyn Young and Nicholas Kaldor, has characteristics that allow to classify it in the realm of complexity economics. We support this claim by a historical reconstruction of the Smithian growth theory highlighting the characteristics that we show also characterize complex systems. We compare this perspective with the one developed by the traditional economic approach, rooted in general equilibrium, and describe a simple alternative model

The dynamic interdependence in the demand of primary and emergency secondary care: A hidden Markov approach

2021

This paper develops an extension of the class of finite mixture models for longitudinal count data to the bivariate case by using a trivariate reduction technique and a hidden Markov chain approach. The model allows for disentangling unobservable time-varying heterogeneity from the dynamic effect of utilisation of primary and secondary care and measuring their potential substitution effect. Three points of supports adequately describe the distribution of the latent states suggesting the existence of three profiles of low, medium and high users who shows persistency in their behaviour, but not permanence as some switch to their neighbour's profile.