Search results for "multidimensional"

Unveiling Bacterial Interactions through Multidimensional Scaling and Dynamics Modeling

2015

AbstractWe propose a new strategy to identify and visualize bacterial consortia by conducting replicated culturing of environmental samples coupled with high-throughput sequencing and multidimensional scaling analysis, followed by identification of bacteria-bacteria correlations and interactions. We conducted a proof of concept assay with pine-tree resin-based media in ten replicates, which allowed detecting and visualizing dynamical bacterial associations in the form of statistically significant and yet biologically relevant bacterial consortia.

<title>Structure analysis of the Polish academic information society using MDS method</title>

2006

The article presents the methodology of webometrics research and analysis aiming at determining similar features of objects belonging to the Polish information society, which uses the Internet and its www resources for communication purposes. In particular, the analysis applies to the selected Polish technical universities. The research was carried out in several phases - on different data groups - with regards to the Internet space and time changes. The results have been presented in a form of two and three-dimensional topography maps. For the purposes of this analysis, the computer methods of multidimensional scaling were used. The research will be further continued for a selected group o…

Statistical Multivariate Techniques for the Stock Location Assignment Problem

1998

In previous papers we proposed to apply multivariate statistical methodologies, like Multidimensional Scaling (MDS) and Seriation to the stock location assignment problem of a warehouse, often solved by considering the Cube per Order Index (COI). In this paper we compare the results by MDS, Seriation, a COI based method and the Maximum Path criterion, considering the data of a whole year of a Sicilian supermarket chain warehouse. The comparison is based on the simulated times to satisfy a sample of real orders.

Discrete wavelet transform implementation in Fourier domain for multidimensional signal

2002

Wavelet transforms are often calculated by using the Mallat algorithm. In this algorithm, a signal is decomposed by a cascade of filtering and downsampling operations. Computing time can be important but the filtering operations can be speeded up by using fast Fourier transform (FFT)-based convolutions. Since it is necessary to work in the Fourier domain when large filters are used, we present some results of Fourier-based optimization of the sampling operations. Acceleration can be obtained by expressing the samplings in the Fourier domain. The general equations of the down- and upsampling of digital multidimensional signals are given. It is shown that for special cases such as the separab…

<title>Reaction-diffusion electrical network for image processing</title>

2006

We consider an experimental setup, modelling the FitzHugh-Nagumo equation without recovery term and composed of a 1D nonlinear electrical network made up of discrete bistable cells, resistively coupled. In the first place, we study the propagation of topological fronts in the continuum limit, then in more discrete case. We propose to apply these results to the domain of signal processing. We show that erosion and dilation of a binary signal, can be obtained. Finally, we extend the study to 2D lattices and show that it can be of great interest in image processing techniques.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted fo…

Dynamics of supercooled liquids and glassy solids

2001

Muon Anomaly from Lepton Vacuum Polarization and The Mellin--Barnes Representation

2008

We evaluate, analytically, a specific class of eighth--order and tenth--order QED contributions to the anomalous magnetic moment of the muon. They are generated by Feynman diagrams involving lowest order vacuum polarization insertions of leptons $l=e,\mu$, and $\tau$. The results are given in the form of analytic expansions in terms of the mass ratios $m_e/m_\mu$ and $m_\mu/m_\tau$. We compute as many terms as required by the error induced by the present experimental uncertainty on the lepton masses. We show how the Mellin--Barnes integral representation of Feynman parametric integrals allows for an easy analytic evaluation of as many terms as wanted in these expansions and how its underlyi…

Multidimensional scaling and stock location assignment in a warehouse: an application

1999

By means of an application, in the present paper, the suitability of a multivariate statistical methodology, as multidimensional scaling (MDS), to solve an optimization problem is shown. In particular, considering the stock location assignment problem in the warehouse of a supermarket chain, the solution gained by applying MDS to a set of seven variables is compared with the one obtainable by considering the usual techniques applied in this context. A wide discussion of results is reported. Copyright © 1999 John Wiley & Sons, Ltd.

Greedy and K-Greedy algoritmhs for multidimensional data association

2011

[EN] The multidimensional assignment (MDA) problem is a combinatorial optimization problem arising in many applications, for instance multitarget tracking (MTT). The objective of an MDA problem of dimension $d\in\Bbb{N}$ is to match groups of $d$ objects in such a way that each measurement is associated with at most one track and each track is associated with at most one measurement from each list, optimizing a certain objective function. It is well known that the MDA problem is NP-hard for $d\geq3$. In this paper five new polynomial time heuristics to solve the MDA problem arising in MTT are presented. They are all based on the semi-greedy approach introduced in earlier research. Experimen…

La salute organizzativa nei contesti sanitari: Un’esperienza di ricerca-intervento.

2011

ABSTRACT - From a psychosocial perspective that is intended to produce both understanding and change, especially involv-ing social actors in the construction of shared meanings, this paper illustrates the results of the first stage of an action research process focused on organizational health. The study has been carried out within an Italian hospital combining both quantitative and qualitative methods. Specifically, the data were gathered through the administration of Multidimensional Organizational Health Questionnaire (n=782) and focus group interviews whose transcripts were analyzed with the software T-Lab. The analysis of collected data has allowed us to trace the organizational health…