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The main purpose of this study is to develop a new type of artificial neural network based model for constructing a debris flow warning system. The Chen‐Eu‐Lan river basin, which is located in Central Taiwan, is assigned as the study area. The creek is one of the most well‐known debris flow areas where several damaging debris flows have been reported in the last two decades. The hydrological and geological data, which might have great influence on the occurrence of debris flows, are first collected and analysed, then, the shared near neighbours neural network (SNN + NN) is presented to construct the debris flow warning system for the watershed. SNN is an unsupervised learning method that has the advantage of dealing with non‐globular clusters, besides presenting computational efficiency. By using SNN, the compiled hydro‐geological data set can easily and meaningfully be clustered into several categories. These categories can then be identified as ‘occurrence’ or ‘no‐occurrence’ of debris flows. To improve the effectiveness of the debris flow warning system, a neural network framework is designed to connect all the clusters produced by the SNN method, whereas the connected weights of the network are adjusted through a supervised learning method. This framework is used and its applicability and practicability for debris flow warning are investigated. The results demonstrate that the proposed SNN + NN model is an efficient and accurate tool for the development of a debris flow warning system. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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Paula Garcia Carvalho do Amaral Paulo César Fonseca Giannini Florence Sylvestre Luiz Carlos Ruiz Pessenda 《第四纪科学杂志》2012,27(2):181-191
This paper provides a paleoenvironmental reconstruction of a Late Quaternary lagoon system in the Jaguaruna region of Santa Catarina state, southern Brazil. Integrated results of bulk sedimentary organic matter characterization (δ13C, δ15N and C/N), microfossil (pollen and diatom) and grain‐size analysis from three shallow cores (~2.5 m depth) allowed us to propose an evolving paleogeographic scenario in this coastal region for the last ca. 5500 cal a BP. The lagoonal system in this area was more extensive during the mid‐Holocene than today, with a gradual and continuous lagoon–sea disconnection until the present. We add to the debate regarding relative sea‐level (RSL) variations for the Brazilian coast during the Holocene and discuss the importance of sedimentary dynamics for interpreting changes in coastal ecosystems. The multi‐proxy analysis suggests that changes in coastal ecosystems could be directly related to local sedimentary processes, which are not necessarily linked to RSL fluctuations and/or to climatic variations. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
217.
Catherine Dougados Sylvie Cabrit Jonathan Ferreira Nicholas Pesenti Paulo Garcia Darren O'brien 《Astrophysics and Space Science》2004,293(1-2):45-52
We discuss in this contribution constraints on the origin of mass-loss from young stars brought by recent observations at high angular resolution (0.1″ = 14 AU) of the inner regions of winds from T Tauri stars. Jet widths and collimation scales, the large extent of the velocity profile as well as the detection of rotation signatures agree with predictions from extended (R e ≥ 1 AU) magneto-centrifugal disk wind ejection models. Detected poloidal and toroidal velocities imply large ejection efficiencies (ξ ? 0.05, λ ? 10), suggesting that thermal gradients (originating in an accretion heated disk corona for example) play an important role in accelerating the flow. 相似文献
218.
On retrieving patterns in environmental sensor data 总被引:1,自引:0,他引:1
As many sensor networks are currently being deployed for environmental monitoring, there is a growing need to develop systems
and applications for managing, processing and retrieving massive amounts of data generated from those networks. In this research,
a query answering system with pattern mining techniques is investigated specifically for marine sensor data. We consider three
applications of pattern mining: similar pattern search, predictive query and query by clustering. In pattern mining for query
answering, we adopt the dynamic time warping (DTW) method for similarity measurement. We also propose the use of a query relaxation
approach that recommends users change parameters of a given query to get an answer. Finally, we show implementation results
of pattern query answering in a marine sensor network deployed in the South East of Tasmania, Australia. Pattern query answering
system benefits in accessing and discovering knowledge from sensor data for decision making purposes. 相似文献
219.
The purpose of this work is to characterize the hydrochemical behavior of acid mine drainages (AMD) and superficial waters
from the Adoria mine area (Northern Portugal). Samples of superficial and mine drainage water were collected for one year,
bi-monthly, with pH, temperature, Eh, conductivity and HCO3 determined in situ with chemical analyses of SO4, Ca, K, Mg, Na, Cl, Ag, As, Bi, Co, Cu, Fe, Mn, Ni, Pb, Zn and Cd. In the mine, there are acidic waters, with low pH and
significant concentrations of SO4, and metals (Fe, Mn, Zn, Cu, Pb, Cd and Ni), while in the superficial natural stream waters outside the mine, the pH is close
to neutral, with low conductivity and lower metal concentrations. The stream waters inside the mine influence are intermediate
in composition between AMD and natural stream waters outside the mine influence. Principal Component Analysis (PCA) shows
a clear separation between AMD galleries and AMD tailings, with tailings having a greater level of contamination. 相似文献
220.
Paulo Valladares Soares Sueli Yoshinaga Pereira Silvio Jorge C. Simoes George de Paula Bernardes Sérgio Augusto Barbosa Isabel Cristina B. Trannin 《Environmental Earth Sciences》2012,67(6):1685-1694
This work describes the methodological approach used for mapping the potential infiltration areas of the Guaratinguetá watershed (160?km2), situated in Southeastern Brazil. The method is considered a qualitative approach, which takes into account thematic maps (geology, pedology, geomorphology, and land use/land cover) and the precipitation spatial distribution. A group of experts in Earth Sciences and Geotechnical Engineering has applied an infiltration potential scale factor that ranges from 5 (highest influence) to 1 (lowest influence). The final infiltration map was produced using several ArcGIS? tools. The results showed that the most suitable (very high) infiltration areas represent only around 7% of the watershed area, which are associated with smooth and gentle hills, fluvial Tertiary sediments and yellow oxisols. However, growing impacts caused by land farming and urban developments require urgent planning for this region. Areas with high to moderate capacity of infiltration represent around 56% of the watershed and are found in the domain of igneous-metamorphic rocks associated with steep hill-slopes and relatively well-preserved forest fragments. This region requires a land-use strategy, such as reforestation programs, in order to increase the infiltration capacity of the watershed. 相似文献