Fuzzy heterogeneous neurons for imprecise classification problems

In the classical neuron model, inputs are continuous real-valued quantities. However, in many important domains from the real world, objects are described by a mixture of continuous and discrete variables, usually containing missing information and uncertainty. In this paper, a general class of neuron models accepting heterogeneous inputs in the form of mixtures of continuous (crisp and/or fuzzy) and discrete quantities admitting missing data is presented. From these, several particular models can be derived as instances and different neural architectures constructed with them. Such models deal in a natural way with problems for which information is imprecise or even missing. Their possibilities in classification and diagnostic problems are here illustrated by experiments with data from a real-world domain in the field of environmental studies. These experiments show that such neurons can both learn and classify complex data very effectively in the presence of uncertain information.Peer ReviewedPostprint (author's final draft

A remote sensing evaluation of potential for sinkhole occurrence

The relationship between lowering of the water table and sinkhole development in Pierson and in Hillsborough County, Florida was investigated. The locations of recently developed (1973) collapses were examined with respect to lineaments or fracture traces that are expressed in the terrain and visible in aerial photography and satellite imagery. It was anticipated that these relationships would provide the basis for establishment of criteria for mapping those land areas that have the greatest potential for sinkhole development. A very good correlation was found between mapped lineament intersections and known location of sinkhole occurrences for both study areas. This indicates that lineament and fracture trace mapping may be very useful in locating zones with the greatest potential for sinkhole development. It is further shown that this information is quite beneficial in land use planning applications

The role of GPR techniques in determining ice cave properties: Peña Castil ice cave, Picos de Europa

Producción CientíficaThe structure and ice content of ice caves are poorly understood. Ground penetrating radar (GPR) can provide useful insights but has only rarely been applied to ice caves. This paper interprets GPR images (radargrams) in terms of internal structure, stratification, compaction, thickness and volume of the ice block in the Peña Castil ice cave (Central Massif of Picos de Europa, northern Spain), providing the endokarst geometry of the ice cave in GPR data reflections. Eight radargrams were obtained by applying a shielded ground‐coupled antenna with a nominal frequency of 400 MHz. Although the radargrams do not depict the ice–basal bedrock interface, they suggest that the ice block is at least 54 m deep and similarly thick. Some curved reflection signatures suggest a potential vertical displacement in the block of ice, and thus certain dynamics in the ice body. Other images show numerous interbedded clasts and thin sediment layers imaged as banded reflections. In this particular cave a direct visual inspection of the ice stratigraphy is a difficult task but GPR provides clear reflectivity patterns of some of its internal features, making GPR a suitable instrument for this and future studies to achieve a better and broader understanding of the internal behavior of ice caves.Ministerio de Economía, Industria y Competitividad (project CGL2015-68144-R)Ministerio de Agricultura y Pesca, Alimentación y Medio Ambiente (project OAPN-053/2010

Integration of remote-sensing techniques for the preventive conservation of paleolithic cave art in the karst of the Altamira cave

Rock art offers traces of our most remote past and was made with mineral and organic substances in shelters, walls, or the ceilings of caves. As it is notably fragile, it is fortunate that some instances remain intact-but a variety of natural and anthropogenic factors can lead to its disappearance. Therefore, as a valuable cultural heritage, rock art requires special conservation and protection measures. Geomatic remote-sensing technologies such as 3D terrestrial laser scanning (3DTLS), drone flight, and ground-penetrating radar (GPR) allow us to generate exhaustive documentation of caves and their environment in 2D, 2.5D, and 3D. However, only its combined use with 3D geographic information systems (GIS) lets us generate new cave maps with details such as overlying layer thickness, sinkholes, fractures, joints, and detachments that also more precisely reveal interior-exterior interconnections and gaseous exchange; i.e., the state of senescence of the karst that houses the cave. Information of this kind is of great value for the research, management, conservation, monitoring, and dissemination of cave art.This research was funded by the Department of Innovation, Industry, Tourism and Trade of the Regional Government of Cantabria in the context of aid to encourage industrial research and innovation in companies, project “SImulador Climático del Karst de cuevas de especial valor. (SICLIKA),” grant number 2016/INN/25

A Comparative Integrated Geophysical Study of Horseshoe Chimney Cave, Colorado Bend State Park, Texas

An integrated geophysical study was performed over a known cave in Colorado Bend State Park (CBSP), Texas, where shallow karst features are common within the Ellenberger Limestone. Geophysical survey such as microgravity, ground penetrating radar (GPR), direct current (DC) resistivity, capacitively coupled (CC) resistivity, induced polarization (IP) and ground conductivity (GC) measurements were performed in an effort to distinguish which geophysical method worked most effectively and efficiently in detecting the presence of subsurface voids, caves and collapsed features. Horseshoe Chimney Cave (HCC), which is part of a larger network of cave systems, provides a good control environment for this research. A 50 x 50 meter grid, with 5 m spaced traverses was positioned around the entrance to HCC. Geophysical techniques listed above were used to collect geophysical data which were processed with the aid of commercial software packages. A traditional cave survey was conducted after geophysical data collection, to avoid any bias in initial data collection. The survey of the cave also provided ground truthing. Results indicate the microgravity followed by CC resistivity techniques worked most efficiently and were most cost effective, while the other methods showed varying levels of effectiveness

Integrated geophysical surveys to assess the structural conditions of a karstic cave of archaeological importance

An integrated geophysical survey using both the electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) methods was undertaken over a cave of great archaeological interest in southern Italy. The survey was performed to assess the stability of the carbonate rock roof of the cave. A geophysical survey was preferred to boreholes and geotechnical tests, in order to avoid the risk of mass movements. The interpretation of integrated data from ERT and GPR resulted in an evaluation of some of the electromagnetic (EM) characteristics (such as the EM wave velocity) and the detection of discontinuities (fractures) in the carbonate rock. It is well known that rock fractures constitute a serious problem in cave maintenance, and progressive cracking within the bed rock is considered to be one of the main causes of collapse. An analysis of the back-scattered energy was also required for the GPR data interpretation. Cracks within the bedrock were detected to a depth of about 2 m by using GPR, which allowed for the identification of the loosened zone around the cave

An airborne geophysical survey of part of west Dyfed, South Wales, and some related ground surveys

A detailed airborne geophysical survey has been made of part of west Dyfed at a flying height of 75 m with magnetic, electromagnetic (VLF-EM) and radiometric equipment mounted in a helicopter. The area of 670 km2 includes the Precambrian anticlines of St David’s and Hayscastle, the Fishguard, Sealyham and Trefgarne volcanic groups, and the adjacent Lower Palaeozoic sediments with associated basic intrusions. Ground geophysical surveys were carried out at 33 localities to confirm the nature and the sources of the airborne anomalies, and a geological examination was also made at selected localities. Rock samples were collected for petrographical examination and physical property determinations. A regional gravity survey was also carried out. Some details of the geophysical methods and data presentation are included together with a map at a scale of 1:50 000 summarising the main results obtained from interpretations of the airborne geophysical surveys. The aeromagnetic data clearly show the distribution of the Precambrian rocks, the numerous dolerite intrusions, and some of the pillow lavas associated with the Fishguard Volcanic Group. This distribution generally confirms the outcrop pattern based on geological mapping. The magnetic data are likely to be more reliable for mapping on a more detailed scale, due to the extensive drift cover which hinders geological mapping in many places, and they have also revealed some large scale structures, in- The airborne VLF anomalies are most obvious at lithological boundaries with large resistivity contrasts such as the Precambrian/Lower Palaeozoic sediment and dolerite/sediment contacts. The radiometric data provide little obvious additional information. Although the west Dyfed area has no significant mining history, some exploration activity has taken place there in recent years (Allen, Cooper and others 1985; Cameron and others, 1984; Brown and others, 1987). One of the main restrictions on exploration has been the lack of rock exposure in much of the inland area and the airborne geophysical survey was undertaken as partial compensation for this