Search results for "Spatial"

Sampling procedure in a willow plantation for chemical elements important for biomass combustion quality

2015

Willow (Salix spp.) is expected to contribute significantly to the woody bioenergy system in the future, so more information on how to sample the quality of the willow biomass is needed. The objectives of this study were to investigate the spatial variation of elements within shoots of a willow clone ‘Tordis’, and to reveal the relationship between sampling position, shoot diameters, and distribution of elements. Five Tordis willow shoots were cut into 10–50 cm sections from base to top. The ash content and concentration of twelve elements (Al, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, P, Si, and Zn) in each section were determined. The results showed large spatial variation in the distribution of mos…

La Sicilia

2009

Measurement of Agglomeration and Spatial Effects

2009

The aim of the paper is to examine the influence of spatial agglomeration on the employment growth in the sicilian local labor systems. In this paper we want provide a methodological contribution to agglomeration literature. On the base of the hypothesis that the forces of agglomeration do not use up their effects inside of a single SLL but they extend to more wide geographic areas, and their effect fall down on the adjacent territorial partition; we have modified the traditional agglomeration index built by Maurell and Sédillot in 1999, at first, inverting the role of the industry with that one of the area, so we obtain a measure of agglomeration for each area, and then we included a spati…

Deep Completion Autoencoders for Radio Map Estimation

2022

Radio maps provide metrics such as power spectral density for every location in a geographic area and find numerous applications such as UAV communications, interference control, spectrum management, resource allocation, and network planning to name a few. Radio maps are constructed from measurements collected by spectrum sensors distributed across space. Since radio maps are complicated functions of the spatial coordinates due to the nature of electromagnetic wave propagation, model-free approaches are strongly motivated. Nevertheless, all existing schemes for radio occupancy map estimation rely on interpolation algorithms unable to learn from experience. In contrast, this paper proposes a…

A Spatial-Temporal Correlation Approach for Data Reduction in Cluster-Based Sensor Networks

2019

International audience; In a resource-constrained Wireless Sensor Networks (WSNs), the optimization of the sampling and the transmission rates of each individual node is a crucial issue. A high volume of redundant data transmitted through the network will result in collisions, data loss, and energy dissipation. This paper proposes a novel data reduction scheme, that exploits the spatial-temporal correlation among sensor data in order to determine the optimal sampling strategy for the deployed sensor nodes. This strategy reduces the overall sampling/transmission rates while preserving the quality of the data. Moreover, a back-end reconstruction algorithm is deployed on the workstation (Sink)…

Spatial noise-aware temperature retrieval from infrared sounder data

2020

In this paper we present a combined strategy for the retrieval of atmospheric profiles from infrared sounders. The approach considers the spatial information and a noise-dependent dimensionality reduction approach. The extracted features are fed into a canonical linear regression. We compare Principal Component Analysis (PCA) and Minimum Noise Fraction (MNF) for dimensionality reduction, and study the compactness and information content of the extracted features. Assessment of the results is done on a big dataset covering many spatial and temporal situations. PCA is widely used for these purposes but our analysis shows that one can gain significant improvements of the error rates when using…

Data-Driven Spectrum Cartography via Deep Completion Autoencoders

2019

Spectrum maps, which provide RF spectrum metrics such as power spectral density for every location in a geographic area, find numerous applications in wireless communications such as interference control, spectrum management, resource allocation, and network planning to name a few. Spectrum cartography techniques construct these maps from a collection of measurements collected by spatially distributed sensors. Due to the nature of the propagation of electromagnetic waves, spectrum maps are complicated functions of the spatial coordinates. For this reason, model-free approaches have been preferred. However, all existing schemes rely on some interpolation algorithm unable to learn from data. …

Anamorphic fractional Fourier transform: optical implementation and applications

1995

An additional degree of freedom is introduced to fractional-Fourier-transform systems by use of anamorphic optics. A different fractional Fourier order along the orthogonal principal directions is performed. A laboratory experimental system shows preliminary results that demonstrate the proposed theory. Applications such as anamorphic fractional correlation and multiplexing in fractional domains are briefly suggested.

Space–bandwidth product of optical signals and systems

1996

The space–bandwidth product (SW) is fundamental for judging the performance of an optical system. Often the SW of a system is defined only as a pure number that counts the degrees of freedom of the system. We claim that a quasi-geometrical representation of the SW in the Wigner domain is more useful. We also represent the input signal as a SW in the Wigner domain. For perfect signal processing it is necessary that the system SW fully embrace the signal SW.

Tiempo para hablar y tiempo para callar: uso y función del silencio en un auto religioso de fines del XVI

2013

En este artículo nos proponemos una primera aproximación a un auto religioso inédito de fines del siglo XVI titulado "Auto de la cena a lo divino", tomando como eje articulatorio del mismo la estrategia comunicativa que el anónimo dramaturgo lleva a cabo con la noción de silencio. En la primera parte analizaremos ampliamente el modo en que el autor se sirve de la ausencia de palabras para crear una atmósfera ritual y celebrativa que vincula esta pieza dramática con la liturgia. A continuación subrayaremos algunas fórmulas teatrales inherentes al lenguaje teatral relacionadas con el silencio que se descubren ineficaces en cuanto a su función primordial de generar tensión dramática, pero sí c…