An inversion scheme based on normal-mode representation of the acoustic field is applied in ocean acoustic tomography for a range-dependent reconstruction of the sound speed variations at a vertical slice. The scheme ...
An inversion scheme based on normal-mode representation of the acoustic field is applied in ocean acoustic tomography for a range-dependent reconstruction of the sound speed variations at a vertical slice. The scheme is based on the assumption that modal phase can be measured by suitable mode filtering at some range from the sound source. Two cases have been considered. The first of them makes no use of oceanographic information on the variability to be recovered, while the second one makes use of empirical orthogonal functions (EOFs) that describe sound speed variations in the ocean. The data used in the applications presented in this paper are synthetic ones. It is shown that both modal inversion schemes can be used for the recovery of range-dependent sound speed variations of compact support in the ocean, provided that a range dependent background environment is used to describe an initial guess of the variations. The scheme is more powerful when EOFs are used.
In this paper we present an algorithm for the density and sound speed reconstruction of a two-layered bottom consisting of a fluid sediment layer over a fluid substrate of semi-infinite extend. The thickness of the se...
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In this paper we present an algorithm for the density and sound speed reconstruction of a two-layered bottom consisting of a fluid sediment layer over a fluid substrate of semi-infinite extend. The thickness of the sediment as well as the attenuation coefficients in the botton layer are also recovered. Measurements of the reflection coefficients of plane waves for eight source frequencies incident normally upon the water bottom interface are needed. The minimum number of frequencies needed for the algorithm is eight as it will be seen in the following sections, however if the reflection coefficient is known for more than eight frequencies the method makes use of the excess frequencies, improving the final solution in a postprocessing way. We first introduce our model, explain the method of solution and present the major steps of the algorithm. Then we will show results using synthetic data, for four cases which were tested, as well as results from a tank experiment.< >
A model for case II diffusion into polymers is presented. The addition of stress terms to the Fickian flux is used to produce the characteristics progressive front. The stress in turn obeys a concentration-dependent e...
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A model for case II diffusion into polymers is presented. The addition of stress terms to the Fickian flux is used to produce the characteristics progressive front. The stress in turn obeys a concentration-dependent evolution equation. The model equations are analyzed in the limit of small diffusivity for the problem of penetration into a semiinfinite medium. Provided that the coefficient functions obey two monotonicity conditions, the solvent concentration profile is shown to have a steep front that progresses into the medium. The formulas governing the progression of the front are developed. After the front decays away, the long time behavior of the solution is shown to be a similarity solution as in Fickian diffusion. Two techniques for approximating the solvent concentration and the front position are presented. The first approximation method is a series expansion; formulas are given for the initial speed and deceleration of the front. The second approximation method uses a portion of the long time similarity solution to represent the short time solution behind the front.
In this paper, we present a multiple-scattering solver for nonconvex geometries such as those obtained as the union of a finite number of convex surfaces. For a prescribed error tolerance, this algorithm exhibits a fi...
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In rural, depopulated areas, agritourism, as a development model, could serve the goal of non- exclusively seasonal tourism while creating additional economic opportunities for the locals who are mainly engaged in agr...
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In rural, depopulated areas, agritourism, as a development model, could serve the goal of non- exclusively seasonal tourism while creating additional economic opportunities for the locals who are mainly engaged in agriculture. Kasos is an isolated island of the Dodecanese, Greece, preserving interesting elements of the authentic agricultural practices and architecture like terraces serving the island’s agricultural cultivation, mills and mitata, small stone- built *** served as a case study of AEI program (Sustainable Development of Less Developed Regions and Isolated Areas by Creating New Touristic Resources and Products through Analysis, Documentation and Modelling of Cultural Assets using Innovative ICT Applications, project code:T2EDK- 01278). For thιs island that lies within the wider region of Rhodes, it is possible with the appropriate development of new touristic resources and products through the advancement of the unique architectural, cultural and environmental assets to orient towards them special parts of the touristic flow from Rhodes, creating new touristic activity by increasing the residence beyond the daily or short time tourism, as it stands for *** the analysis of the study area, research in local archives and communication with the municipality and local stakeholders was conducted. Thus, both the special features of the island and the needs of the local community were identified, organized, classified and presented in GIS maps. The implementation of a GIS for Kasos Island aims to provide a comprehensive representation of the different aspects of the island, providing useful information for policy-making and the development of strategic cultural and agrotourism plans to the local authorities and *** to the integrated plan for Kasos by AEI program, the island could preserve its special rural identity while revealing its cultural and environmental assets and attracting external economies within an agritourism mod
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