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51.
A decision support system (DSS) has been developed to assist expert and non-expert users in the evaluation and selection of
eco-engineering strategies for slope protection. This DSS combines a qualitative hazard assessment of erosion and mass movements
with a detailed catalogue of eco-engineering strategies for slope protection of which the suitability is evaluated in relation
to the data entered. The slope decision support system (SDSS) is a knowledge based DSS in which knowledge is stored in frames
containing rules that can evaluate the available information for a project, stored as project specific information (PSI) in
a data file. The advantages of such a system are that it accepts incomplete information and that the qualitative nature of
the information does not instil the user with a sense of unjustified exactitude. By its multidisciplinary and progressive
nature, the DSS will be of value during the initial stages of an eco-engineering project when data collection and the potential
of different eco-engineering strategies are considered. The accent of the output of the DSS is on the application of eco-engineering
strategies for slope protection as an environmentally-friendly solution aiding sustainable development. For its acceptance
within the engineering community, the DSS needs to prove its predictive capacity. Therefore, its performance has been benchmarked
against successful and unsuccessful cases of slope stabilisation using eco-engineering. The target audience and the areas
of application of this DSS are reviewed and the strategies for further development in this area suggested. 相似文献
52.
Faisal Hossain 《Natural Hazards》2006,37(3):263-276
The three most important components necessary for functioning of an operational flood warning system are: (1) a rainfall measuring
system; (2) a soil moisture updating system; and, (3) a surface discharge measuring system. Although surface based networks
for these systems can be largely inadequate in many parts of the world, this inadequacy particularly affects the tropics,
which are most vulnerable to flooding hazards. Furthermore, the tropical regions comprise developing countries lacking the
financial resources for such surface-based monitoring. The heritage of research conducted on evaluating the potential for
measuring discharge from space has now morphed into an agenda for a mission dedicated to space-based surface discharge measurements.
This mission juxtaposed with two other upcoming space-based missions: (1) for rainfall measurement (Global Precipitation Measurement,
GPM), and (2) soil moisture measurement (Hydrosphere State, HYDROS), bears promise for designing a fully space-borne system
for early warning of floods. Such a system, if operational, stands to offer tremendous socio-economic benefit to many flood-prone
developing nations of the tropical world. However, there are two competing aspects that need careful assessment to justify
the viability of such a system: (1) cost-effectiveness due to surface data scarcity; and (2) flood prediction uncertainty
due to uncertainty in the remote sensing measurements. This paper presents the flood hazard mitigation opportunities offered
by the assimilation of the three proposed space missions within the context of these two competing aspects. The discussion
is cast from the perspective of current understanding of the prediction uncertainties associated with space-based flood prediction.
A conceptual framework for a fully space-borne system for early-warning of floods is proposed. The need for retrospective
validation of such a system on historical data comprising floods and its associated socio-economic impact is stressed. This
proposal for a fully space-borne system, if pursued through wide interdisciplinary effort as recommended herein, promises
to enhance the utility of the three space missions more than what their individual agenda can be expected to offer. 相似文献
53.
54.
Groundwater study using remote sensing and geographic information systems (GIS) in the central highlands of Eritrea 总被引:3,自引:1,他引:3
Remote sensing, evaluation of digital elevation models (DEM), geographic information systems (GIS) and fieldwork techniques were combined to study the groundwater conditions in Eritrea. Remote sensing data were interpreted to produce lithological and lineament maps. DEM was used for lineament and geomorphologic mapping. Field studies permitted the study of structures and correlated them with lineament interpretations. Hydrogeological setting of springs and wells were investigated in the field, from well logs and pumping test data. All thematic layers were integrated and analysed in a GIS. Results show that groundwater occurrence is controlled by lithology, structures and landforms. Highest yields occur in basaltic rocks and are due to primary and secondary porosities. High yielding wells and springs are often related to large lineaments, lineament intersections and corresponding structural features. In metamorphic and igneous intrusive rocks with rugged landforms, groundwater occurs mainly in drainage channels with valley fill deposits. Zones of very good groundwater potential are characteristic for basaltic layers overlying lateritized crystalline rocks, flat topography with dense lineaments and structurally controlled drainage channels with valley fill deposits. The overall results demonstrate that the use of remote sensing and GIS provide potentially powerful tools to study groundwater resources and design a suitable exploration plan.The online version of the original article can be found at 相似文献
55.
Decision-support systems for groundwater protection: innovative tools for resource management 总被引:1,自引:0,他引:1
Stefan Kollarits Gerhard Kuschnig Miran Veselic Ante Pavicic Corrado Soccorso Marina Aurighi 《Environmental Geology》2006,49(6):840-848
Governmental authorities are forced by law to make decisions within the framework of European, national and regional directives
in the fields of spatial planning, groundwater and environmental protection. These tasks can be supported by a decision-support
system, which integrates data from various sources and helps to make decision processes more effective and transparent. Basic
work for such a decision support system has been done in a transnational and interdisciplinary project (Interreg II C: KATER),
including metadata definition, metadata system, cartographic tools and GIS tools. The direct integration of these tools and
information in the decision process will be implemented in the next few years (project KATER II). 相似文献
56.
57.
梅雨锋云系的结构特征及其成因分析 总被引:7,自引:9,他引:7
利用逐时卫星遥感观测资料和地面测站的降水资料,分析了江淮流域2003年6月22~26日暴雨过程中梅雨锋云系的演变、结构特征和形成原因。结果表明,梅雨锋云系为一条TBB的低值带,稳定少动,其上分布着中尺度对流系统(MCS),而中尺度对流系统是由不同尺度、不同强度.的对流单体(包括中β和中γ尺度对流单体)组成的,从而使得梅雨锋云系产生不均匀的降水分布(包括时间上和空间上)。在该暴雨过程中,梅雨锋云系充分体现了中尺度对流系统中所包括的3类组织结构形式。梅雨锋云系与中高纬度云系或热带辐合带云系之间的相互作用与暴雨过程关系密切,梅雨锋云系的维持和发展与强大的黄淮气旋云系直接相关,它是江淮流域上空冷暖气流交汇的结果。 相似文献
58.
Trevor Quinn A.-Xing Zhu James E. Burt 《International Journal of Applied Earth Observation and Geoinformation》2005,7(4):324-338
Hydro-ecological modelers often use spatial variation of soil information derived from conventional soil surveys in simulation of hydro-ecological processes over watersheds at mesoscale (10–100 km2). Conventional soil surveys are not designed to provide the same level of spatial detail as terrain and vegetation inputs derived from digital terrain analysis and remote sensing techniques. Soil property layers derived from conventional soil surveys are often incompatible with detailed terrain and remotely sensed data due to their difference in scales. The objective of this research is to examine the effect of scale incompatibility between soil information and the detailed digital terrain data and remotely sensed information by comparing simulations of watershed processes based on the conventional soil map and those simulations based on detailed soil information across different simulation scales. The detailed soil spatial information was derived using a GIS (geographical information system), expert knowledge, and fuzzy logic based predictive mapping approach (Soil Land Inference Model, SoLIM). The Regional Hydro-Ecological Simulation System (RHESSys) is used to simulate two watershed processes: net photosynthesis and stream flow. The difference between simulation based on the conventional soil map and that based on the detailed predictive soil map at a given simulation scale is perceived to be the effect of scale incompatibility between conventional soil data and the rest of the (more detailed) data layers at that scale. Two modeling approaches were taken in this study: the lumped parameter approach and the distributed parameter approach. The results over two small watersheds indicate that the effect does not necessarily always increase or decrease as the simulation scale becomes finer or coarser. For a given watershed there seems to be a fixed scale at which the effect is consistently low for the simulated processes with both the lumped parameter approach and the distributed parameter approach. 相似文献
59.
通过引人泊松括号,分析了无限维Hamilton的性质,并将其推广到广义Hamilton系统,且从理论和实用角度讨论了这类广义Hamilton系统的辛格式构造问题,从而为辛几何算法在一般的时间发展方程的数值求解提供新的具体途径。 相似文献
60.
The seismic response of single‐degree‐of‐freedom (SDOF) systems incorporating flag‐shaped hysteretic structural behaviour, with self‐centring capability, is investigated numerically. For a SDOF system with a given initial period and strength level, the flag‐shaped hysteretic behaviour is fully defined by a post‐yielding stiffness parameter and an energy‐dissipation parameter. A comprehensive parametric study was conducted to determine the influence of these parameters on SDOF structural response, in terms of displacement ductility, absolute acceleration and absorbed energy. This parametric study was conducted using an ensemble of 20 historical earthquake records corresponding to ordinary ground motions having a probability of exceedence of 10% in 50 years, in California. The responses of the flag‐shaped hysteretic SDOF systems are compared against the responses of similar bilinear elasto‐plastic hysteretic SDOF systems. In this study the elasto‐plastic hysteretic SDOF systems are assigned parameters representative of steel moment resisting frames (MRFs) with post‐Northridge welded beam‐to‐column connections. In turn, the flag‐shaped hysteretic SDOF systems are representative of steel MRFs with newly proposed post‐tensioned energy‐dissipating connections. Building structures with initial periods ranging from 0.1 to 2.0s and having various strength levels are considered. It is shown that a flag‐shaped hysteretic SDOF system of equal or lesser strength can always be found to match or better the response of an elasto‐plastic hysteretic SDOF system in terms of displacement ductility and without incurring any residual drift from the seismic event. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献