16 research outputs found

    Web-based Information Systems: Data Monitoring, Analysis and Reporting for Measurements and Simulations

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    This paper describes the concept, implementation and application of the Web-based Information System ‘Turtle’ for data monitoring, analysis, reporting and management in engineering projects. The system uses a generalised object-oriented approach for information modelling of physical state variables from measurements and simulations by sets of tensor objects and is implemented platform-independently as a Web application. This leads to a more flexible handling of measurement and simulation information in distributed and interdisciplinary engineering projects based on the concept of information sharing. The potential and advantages of Web-based information systems like ‘Turtle’ are described for one selected application example: a measurement programme dealing with the physical limnology of Lake Constance

    Web-based Collaborative Engineering based on Information Sharing - HydroWeb: An Education Experiment in the Internet

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    This paper describes the concept and experiences of the international Open Distance Learning Course ‘HydroWeb’. This course deals with the introduction of Web-based Collaborative Engineering in standard education programmes of water related engineering and civil engineering based on information sharing. Organized under the umbrella of IAHR and ETNET21 this course is collaboration from several universities from all over the world. Started in 1999 the course demonstrates the potential and innovative opportunities of Web-Technology in education, research and engineering: Students from the different partner universities form small distributed teams to solve a given engineering problem in a time window of two weeks. To overcome the spatial distribution the students apply modern Web technology such as video conferencing, application sharing and document management. All results as well as the final reports are presented as Web document on a shared Web-based project platform (http://www.hydro-web.org). Besides the experiences to apply standard Web tools and working methods based on information sharing instead the conventional information exchange in the daily engineering work the students improve their soft skills operate successfully in international and interdisciplinary project environments as part of the ‘Technical Culture’ of nowadays

    WWW based Simulation Systems and Project Platforms in Civil Engineering

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    The availability of the WWW technology and the introduction of the Internet as basic resource like water, electricity or gas changes dramatically normal live, business and of course civil engineering. New technologies enable innovative technical solutions and offer new potential for improvements towards support of humans nature appropriate ways of working. This demands a new culture of work and collaboration. To contribute to theses challenges is a matter the discipline 'Bauinformatik' by supporting related research, development, education and training in civil engineering. This contribution to the IKM Conference 2000 in Weimar sketches selected research and education activities of the institutes of the authors on the topics of WWW based simulation systems (example WEASEL) and of WWW based project platforms (projects MorWin and TaiGer as well as an European education experiment). Both topics supports the collaboration by new ways of tele cooperation in international, heterogeneous and interdisciplinary engineering. Demonstration from this developments and projects will be used to illustrate the dimension of changes in civil engineering in due to modern ICT

    Ensemble analysis of complex network properties—an MCMC approach

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    What do generic networks that have certain properties look like? We use relative canonical network ensembles as the ensembles that realize a property R while being as indistinguishable as possible from a background network ensemble. This allows us to study the most generic features of the networks giving rise to the property under investigation. To test the approach we apply it to study properties thought to characterize ‘small-world networks’. We consider two different defining properties, the ‘small-world-ness’ of Humphries and Gurney, as well as a geometric variant. Studying them in the context of Erdős-Rényi and Watts-Strogatz ensembles we find that all ensembles studied exhibit phase transitions to systems with large hubs and in some cases cliques. Such features are not present in common examples of small-world networks, indicating that these properties do not robustly capture the notion of small-world networks. We expect the overall approach to have wide applicability for understanding network properties of real world interest, such as optimal ride-sharing designs, the vulnerability of networks to cascades, the performance of communication topologies in coordinating fluctuation response or the ability of social distancing measures to suppress disease spreading

    Flood hazard mapping for data-scarce and ungauged coastal river basins using advanced hydrodynamic models, high temporal-spatial resolution remote sensing precipitation data, and satellite imageries

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    This paper presents an integrated approach to simulate flooding and inundation for small- and medium-sized coastal river basins where measured data are not available or scarce. By coupling the rainfall–runoff model, the one-dimensional and two-dimensional models, and the integration of these with global tide model, satellite precipitation products, and synthetic aperture radar imageries, a comprehensive flood modeling system for Tra Bong river basin selected as a case study was set up and operated. Particularly, in this study, the lumped conceptual model was transformed into the semi-distributed model to increase the parameter sets of donor basins for applying the physical similarity approach. The temporal downscaling technique was applied to disaggregate daily rainfall data using satellite-based precipitation products. To select an appropriate satellite-derived rainfall product, two high temporal-spatial resolution products (0.1 × 0.1 degrees and 1 h) including GSMaP_GNRT6 and CMORPH_CRT were examined at 1-day and 1-h resolutions by comparing with ground-measured rainfall. The CMORPH_CRT product showed better performance in terms of statistical errors such as Correlation Coefficient, Probability of Detection, False Alarm Ratio, and Critical Success Index. Land cover/land use, flood extent, and flood depths derived from Sentinel-1A imageries and a digital elevation model were employed to determine the surface roughness and validate the flood modeling. The results obtained from the modeling system were found to be in good agreement with collected data in terms of NSE (0.3–0.8), RMSE (0.19–0.94), RPE (− 213 to 0.7%), F1 (0.55), and F2 (0.37). Subsequently, various scenarios of flood frequency with 10-, 20-, 50-, and 100-year return periods under the probability analysis of extreme values were developed to create the flood hazard maps for the study area. The flood hazards were then investigated based on the flood intensity classification of depth, duration, and velocity. These hazard maps are significantly important for flood hazard assessments or flood risk assessments. This study demonstrated that applying advanced hydrodynamic models on computing flood inundation and flood hazard analysis in data-scarce and ungauged coastal river basins is completely feasible. This study provides an approach that can be used also for other ungauged river basins to better understand flooding and inundation through flood hazard mapping.Deutscher Akademischer Austauschdienst http://dx.doi.org/10.13039/501100001655Brandenburgische TU Cottbus-Senftenberg (5408

    Flood hazard mapping for data-scarce and ungauged coastal river basins using advanced hydrodynamic models, high temporal-spatial resolution remote sensing precipitation data, and satellite imageries

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    <jats:title>Abstract</jats:title><jats:p>This paper presents an integrated approach to simulate flooding and inundation for small- and medium-sized coastal river basins where measured data are not available or scarce. By coupling the rainfall–runoff model, the one-dimensional and two-dimensional models, and the integration of these with global tide model, satellite precipitation products, and synthetic aperture radar imageries, a comprehensive flood modeling system for Tra Bong river basin selected as a case study was set up and operated. Particularly, in this study, the lumped conceptual model was transformed into the semi-distributed model to increase the parameter sets of donor basins for applying the physical similarity approach. The temporal downscaling technique was applied to disaggregate daily rainfall data using satellite-based precipitation products. To select an appropriate satellite-derived rainfall product, two high temporal-spatial resolution products (0.1 × 0.1 degrees and 1 h) including GSMaP_GNRT6 and CMORPH_CRT were examined at 1-day and 1-h resolutions by comparing with ground-measured rainfall. The CMORPH_CRT product showed better performance in terms of statistical errors such as Correlation Coefficient, Probability of Detection, False Alarm Ratio, and Critical Success Index. Land cover/land use, flood extent, and flood depths derived from Sentinel-1A imageries and a digital elevation model were employed to determine the surface roughness and validate the flood modeling. The results obtained from the modeling system were found to be in good agreement with collected data in terms of NSE (0.3–0.8), RMSE (0.19–0.94), RPE (− 213 to 0.7%), F1 (0.55), and F2 (0.37). Subsequently, various scenarios of flood frequency with 10-, 20-, 50-, and 100-year return periods under the probability analysis of extreme values were developed to create the flood hazard maps for the study area. The flood hazards were then investigated based on the flood intensity classification of depth, duration, and velocity. These hazard maps are significantly important for flood hazard assessments or flood risk assessments. This study demonstrated that applying advanced hydrodynamic models on computing flood inundation and flood hazard analysis in data-scarce and ungauged coastal river basins is completely feasible. This study provides an approach that can be used also for other ungauged river basins to better understand flooding and inundation through flood hazard mapping.</jats:p&gt

    The analysis of nitrogen load and simulation uncertainty using SWAT in a catchment with paddy field in China

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    Excessive load of nitrogen from anthropogenic sources is a threat to sustaining a healthy aquatic ecosystem. The difficulty in identifying the critical source areas (CSAs) of nitrogen load and apportioning the in-stream nitrogen to individual sources spatially and seasonally has made the Soil and Water Assessment Tool (SWAT) useful for analyzing nitrogen load at the catchment scale. However, the uncertainty of the nitrogen load simulated by SWAT has rarely been analyzed. The two simulations with the highest or the lowest PBIAS of total nitrogen (TN) load were proposed in this study to represent the range of the prediction uncertainty and therefore were used to generate the uncertainty of CSAs and nitrogen source apportionment. The model was set up for the Yuan River Catchment, which is under threat of extensive nitrogen load. Results indicated the highest nitrogen load was from downstream paddy fields with a denser population and 85% of the load was from fertilizer and feedlots. The relatively high prediction uncertainty was observed on both CSAs and source apportionment, which emphasizes the limitation of calibration only based on certain processes and the necessity to consider parameter uncertainty in the application of nitrogen load simulation

    Tracking Urban Expansion Using Random Forests for the Classification of Landsat Imagery (1986–2015) and Predicting Urban/Built-Up Areas for 2025: A Study of the Kumasi Metropolis, Ghana

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    Kumasi is a nodal city and functions as the administrative and economic capital of the Ashanti region in Ghana. Rapid urbanization has been experienced inducing the transformation of various Land Use Land Cover (LULC) types into urban/built-up areas in Kumasi. This paper aims at tracking spatio-temporal LULC changes utilizing Landsat imagery from 1986, 2013 and 2015 of Kumasi. The unique contribution of this research is its focus on urban expansion analysis and the utilization of Random Forest (RF) Classifier for satellite image classification. Change detection, urban land modelling and urban expansion in the sub-metropolitan zones, buffers, density decay curve and correlation analysis were methodologies adopted for our study. The classifier yielded better accuracy compared to earlier works in Ghana. The evaluation of LULC changes indicated that urban/built-up areas are continually increasing at the expense of agricultural and forestlands. The urban/built-up areas occupied 4622.49 hectares (ha) (23.78%), 13,447.50 ha (69.18%) and 14,004.60 ha (72.05%) in 1986, 2013 and 2015, respectively of the 19,438 ha area of Kumasi. Projection indicated that urban/built-up areas will occupy 15,490 ha (79.70%) in 2025. The urban expansion was statistically significant. The results revealed the importance of spatial modeling for environmental management and city planning
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