scholarly journals Can assimilation of crowdsourced streamflow observations in hydrological modelling improve flood prediction?

2015 ◽  
Vol 12 (11) ◽  
pp. 11371-11419 ◽  
Author(s):  
M. Mazzoleni ◽  
M. Verlaan ◽  
L. Alfonso ◽  
M. Monego ◽  
D. Norbiato ◽  
...  
Keyword(s):  
Case Studies ◽  
Low Cost ◽  
Efficiency Index ◽  
Flood Event ◽  
Lead Times ◽  
Hydrological Models ◽  
Flood Prediction ◽  
Physical Sensors ◽  
Synthetic Streamflow ◽  
Hydrological Variables

Abstract. Monitoring stations have been used for decades to properly measure hydrological variables and better predict floods. To this end, methods to incorporate such observations into mathematical water models have also being developed, including data assimilation. Besides, in recent years, the continued technological improvement has stimulated the spread of low-cost sensors that allow for employing crowdsourced and obtain observations of hydrological variables in a more distributed way than the classic static physical sensors allow. However, such measurements have the main disadvantage to have asynchronous arrival frequency and variable accuracy. For this reason, this study aims to demonstrate how the crowdsourced streamflow observations can improve flood prediction if integrated in hydrological models. Two different types of hydrological models, applied to two case studies, are considered. Realistic (albeit synthetic) streamflow observations are used to represent crowdsourced streamflow observations in both case studies. Overall, assimilation of such observations within the hydrological model results in a significant improvement, up to 21 % (flood event 1) and 67 % (flood event 2) of the Nash–Sutcliffe efficiency index, for different lead times. It is found that the accuracy of the observations influences the model results more than the actual (irregular) moments in which the streamflow observations are assimilated into the hydrological models. This study demonstrates how networks of low-cost sensors can complement traditional networks of physical sensors and improve the accuracy of flood forecasting.

scholarly journals Can assimilation of crowdsourced data in hydrological modelling improve flood prediction?

2017 ◽  
Vol 21 (2) ◽  
pp. 839-861 ◽  
Author(s):  
Maurizio Mazzoleni ◽  
Martin Verlaan ◽  
Leonardo Alfonso ◽  
Martina Monego ◽  
Daniele Norbiato ◽  
...  
Keyword(s):  
Case Studies ◽  
Low Cost ◽  
Hydrological Modelling ◽  
Data Availability ◽  
Hydrological Models ◽  
Flood Prediction ◽  
Technological Advances ◽  
Crowdsourced Data ◽  
Streamflow Data ◽  
Synthetic Time Series

Abstract. Monitoring stations have been used for decades to properly measure hydrological variables and better predict floods. To this end, methods to incorporate these observations into mathematical water models have also been developed. Besides, in recent years, the continued technological advances, in combination with the growing inclusion of citizens in participatory processes related to water resources management, have encouraged the increase of citizen science projects around the globe. In turn, this has stimulated the spread of low-cost sensors to allow citizens to participate in the collection of hydrological data in a more distributed way than the classic static physical sensors do. However, two main disadvantages of such crowdsourced data are the irregular availability and variable accuracy from sensor to sensor, which makes them challenging to use in hydrological modelling. This study aims to demonstrate that streamflow data, derived from crowdsourced water level observations, can improve flood prediction if integrated in hydrological models. Two different hydrological models, applied to four case studies, are considered. Realistic (albeit synthetic) time series are used to represent crowdsourced data in all case studies. In this study, it is found that the data accuracies have much more influence on the model results than the irregular frequencies of data availability at which the streamflow data are assimilated. This study demonstrates that data collected by citizens, characterized by being asynchronous and inaccurate, can still complement traditional networks formed by few accurate, static sensors and improve the accuracy of flood forecasts.

scholarly journals Effects of temporal resolution of input precipitation on the performance of hydrological forecasting

2011 ◽  
Vol 29 ◽  
pp. 21-25 ◽  
Author(s):  
F. Wetterhall ◽  
Y. He ◽  
H. Cloke ◽  
F. Pappenberger
Keyword(s):  
Flood Forecasting ◽  
Lead Times ◽  
Data Sets ◽  
Precipitation Data ◽  
Hydrological Models ◽  
Data Set ◽  
Flood Prediction ◽  
Time Period ◽  
Spatial Coverage ◽  
Prediction Systems

Abstract. Flood prediction systems rely on good quality precipitation input data and forecasts to drive hydrological models. Most precipitation data comes from daily stations with a good spatial coverage. However, some flood events occur on sub-daily time scales and flood prediction systems could benefit from using models calibrated on the same time scale. This study compares precipitation data aggregated from hourly stations (HP) and data disaggregated from daily stations (DP) with 6-hourly forecasts from ECMWF over the time period 1 October 2006–31 December 2009. The HP and DP data sets were then used to calibrate two hydrological models, LISFLOOD-RR and HBV, and the latter was used in a flood case study. The HP scored better than the DP when evaluated against the forecast for lead times up to 4 days. However, this was not translated in the same way to the hydrological modelling, where the models gave similar scores for simulated runoff with the two datasets. The flood forecasting study showed that both datasets gave similar hit rates whereas the HP data set gave much smaller false alarm rates (FAR). This indicates that using sub-daily precipitation in the calibration and initiation of hydrological models can improve flood forecasting.

scholarly journals Using Commercial Physical Activity Trackers for Health Promotion Research: Four Case Studies

2018 ◽  
Vol 20 (3) ◽  
pp. 381-389 ◽  
Author(s):  
Gabrielle Turner-McGrievy ◽  
Danielle E. Jake-Schoffman ◽  
Camelia Singletary ◽  
Marquivieus Wright ◽  
Anthony Crimarco ◽  
...  
Keyword(s):  
Physical Activity ◽  
Health Promotion ◽  
Case Studies ◽  
Low Cost ◽  
Lessons Learned ◽  
Assessment Tools ◽  
Sensewear Armband ◽  
Research And Practice ◽  
Activity Trackers ◽  
Tracking Devices

Background. Wearable physical activity (PA) trackers are becoming increasingly popular for intervention and assessment in health promotion research and practice. The purpose of this article is to present lessons learned from four studies that used commercial PA tracking devices for PA intervention or assessment, present issues encountered with their use, and provide guidelines for determining which tools to use. Method. Four case studies are presented that used PA tracking devices (iBitz, Zamzee, FitBit Flex and Zip, Omron Digital Pedometer, Sensewear Armband, and MisFit Flash) in the field—two used the tools for intervention and two used the tools as assessment methods. Results. The four studies presented had varying levels of success with using PA devices and experienced several issues that impacted their studies, such as companies that went out of business, missing data, and lost devices. Percentage ranges for devices that were lost were 0% to 29% and was 0% to 87% for those devices that malfunctioned or lost data. Conclusions. There is a need for low-cost, easy-to-use, accurate PA tracking devices to use as both intervention and assessment tools in health promotion research related to PA.

scholarly journals Development of dynamic system response curve method for estimating initial conditions of conceptual hydrological models

2018 ◽  
Vol 20 (6) ◽  
pp. 1387-1400
Author(s):  
Yiqun Sun ◽  
Weimin Bao ◽  
Peng Jiang ◽  
Xuying Wang ◽  
Chengmin He ◽  
...  
Keyword(s):  
Dynamic System ◽  
Response Curve ◽  
Initial Conditions ◽  
Model Performance ◽  
System Response ◽  
Hydrological Models ◽  
Flood Prediction ◽  
Ill Posed ◽  
Value Decomposition

Abstract The dynamic system response curve (DSRC) has its origin in correcting model variables of hydrologic models to improve the accuracy of flood prediction. The DSRC method can lead to unstable performance since the least squares (LS) method, employed by DSRC to estimate the errors, often breaks down for ill-posed problems. A previous study has shown that under certain assumptions the DSRC method can be regarded as a specific form of the numerical solution of the Fredholm equation of the first kind, which is a typical ill-posed problem. This paper introduces the truncated singular value decomposition (TSVD) to propose an improved version of the DSRC method (TSVD-DSRC). The proposed method is extended to correct the initial conditions of a conceptual hydrological model. The usefulness of the proposed method is first demonstrated via a synthetic case study where both the perturbed initial conditions, the true initial conditions, and the corrected initial conditions are precisely known. Then the proposed method is used in two real basins. The results measured by two different criteria clearly demonstrate that correcting the initial conditions of hydrological models has significantly improved the model performance. Similar good results are obtained for the real case study.

scholarly journals Awheel Along Europe’s Rivers: Geoarchaeological Trails for Cycling Geotourists

2018 ◽  
Vol 10 (1) ◽  
pp. 413-440
Author(s):  
Thomas A. Hose
Keyword(s):  
Roman Empire ◽  
Case Studies ◽  
Low Cost ◽  
Stone Age ◽  
Key Concepts ◽  
Review Study ◽  
Loess Deposits ◽  
River Valleys ◽  
Major Cycle ◽  
Current Provision

AbstractThis review study presents an overview of the potential for the development of geoarchaeological trails for leisure cyclists in Europe. It initially defines and discusses the underpinning key concepts and then examines the nature and main needs of leisure cyclists. It considers and recognises appropriate geo-interpretative themes, of geological/geomorphological and archaeological/historical interest, to employ in developing the trails. Noting that river valleys have long been natural route-ways for human expansion into Europe (as exemplified by the ‘Stone Age’ and the Roman Empire), and that many of today’s major cycle trails are beside rivers with loess deposits, a geoarchaeological geotourism strategy is considered in relation to them. Case studies of specific sites, from central southern England, the Middle Danube and Middle Rhine valleys, outline the current provision and the basis of the proposed trails. Finally, a common relatively low-cost, mixed media, geo-interpretative and promotional approach could generate the impetus to further develop the strategy is suggested.

scholarly journals Lumped damage mechanics as a diagnosis tool of reinforced concrete structures in service: case studies of a former bridge arch and a balcony slab

2021 ◽  
Vol 15 (58) ◽  
pp. 21-32
Author(s):  
Rafael Cunha ◽  
Camila Vieira ◽  
David Amorim
Keyword(s):  
Reinforced Concrete ◽  
Case Studies ◽  
Damage Mechanics ◽  
Low Cost ◽  
Concrete Structures ◽  
Structural Condition ◽  
Numerical Analyses ◽  
Engineering Practice ◽  
Reinforced Concrete Structures ◽  
Diagnosis Tool

Reinforced concrete structures may need repair in order to ensure the designed durability. Such necessity vary in cause and effect, but the structural diagnosis serves as the basis for adopting intervention measures. The assessment of the structural condition usually is made in loco, but sometimes numerical analyses are required as a low cost and effective preliminary diagnosis. In general, numerical analyses use hundreds or thousands of finite elements and nonlinear theories that are not often used in engineering practice. As an alternative, lumped damage mechanics (LDM) uses key concepts of classic fracture and damage mechanics in plastic hinges throughout well-known quantities such as ultimate moment and cracking moment. Such theory describes the concrete cracking by a damage variable, which can be used as a diagnosis criterion. Therefore, this paper presents LDM as a diagnosis tool to analyse actual structures. The case studies presented in this paper are a former bridge arch tested in China and a balcony that collapsed in Brazil. The results show that LDM numerical response of those structures are quite close to laboratory observations (former bridge arch) and in loco measurements (balcony).

scholarly journals Towards assimilation of crowdsourced observations for different levels of citizen engagement: the flood event of 2013 in the Bacchiglione catchment

2017 ◽  
Author(s):  
Maurizio Mazzoleni ◽  
Vivian Juliette Cortes Arevalo ◽  
Uta Wehn ◽  
Leonardo Alfonso ◽  
Daniele Norbiato ◽  
...  
Keyword(s):  
Real Time ◽  
Hydrological Model ◽  
Population Distribution ◽  
Model Performance ◽  
Flood Event ◽  
Target Point ◽  
Citizen Engagement ◽  
Physical Sensors ◽  
Extreme Flood ◽  
Social Sensors

Abstract. Accurate flood predictions are essential to reduce the risk and damages over large urbanized areas. To improve prediction capabilities, hydrological measurements derived by traditional physical sensors are integrated in real-time within mathematic models. Recently, traditional sensors are complemented with low-cost social sensors. However, measurements derived by social sensors (i.e. crowdsourced observations) can be more spatially distributed but less accurate. In this study, we assess the usefulness for model performance of assimilating crowdsourced observations from a heterogeneous network of static physical, static social and dynamic social sensors. We assess potential effects on the model predictions to the extreme flood event occurred in the Bacchiglione catchment on May 2013. Flood predictions are estimated at the target point of Ponte degli Angeli (Vicenza), outlet of the Bacchiglione catchment, by means of a semi-distributed hydrological model. The contribution of the upstream sub-catchment is calculated using a conceptual hydrological model. The flow is propagated along the river reach using a hydraulic model. In both models, a Kalman filter is implemented to assimilate the real-time crowdsourced observations. We synthetically derived crowdsourced observations for either static social or dynamic social sensors because crowdsourced measures were not available. We consider three sets of experiments: (1) only physical sensors are available; (2) probability of receiving crowdsourced observations and (3) realistic scenario of citizen engagement based on population distribution. The results demonstrated the importance of integrating crowdsourced observations. Observations from upstream sub-catchments assimilated into the hydrological model ensures high model performance for high lead time values. Observations next to the outlet of the catchments provide good results for short lead times. Furthermore, citizen engagement level scenarios moved by a feeling of belonging to a community of friends indicated flood prediction improvements when such small communities are located upstream a particular target point. Effective communication and feedback is required between water authorities and citizens to ensure minimum engagement levels and to minimize the intrinsic low-variable accuracy of crowdsourced observations.

Wi-Fi Deployment in Large New Zealand Organizations

2007 ◽  
pp. 24-271
Author(s):  
Bryan Houliston ◽  
Nurul Sarkar
Keyword(s):  
Wireless Networks ◽  
New Zealand ◽  
Case Studies ◽  
Low Cost ◽  
Local Area Networks ◽  
Local Area ◽  
Wireless Local Area Networks ◽  
User Mobility ◽  
Ieee 802.11B

Wi-Fi (also known as IEEE 802.11b) networks are gaining widespread popularity as wireless local area networks (WLANs) due to their simplicity in operation, robustness, low cost, and user mobility offered by the technology. It is a viable technology for wireless local area networking applications in both business and home environments. This chapter reports on a survey of large New Zealand organizations focusing on the level of Wi-Fi deployment, reasons for non-deployment, the scope of deployment, investment in deployment, problems encountered, and future plans. Our findings show that most organizations have at least considered the technology, though a much smaller proportion has deployed it on any significant scale. A follow up review of the latest published case studies and surveys suggests that while Wi-Fi networks are consolidating, interest is growing in wider area wireless networks.

Developing the right brand image

2018 ◽  
Vol 34 (9) ◽  
pp. 35-36
Keyword(s):  
Case Studies ◽  
Design Methodology ◽  
Reading Time ◽  
Brand Image ◽  
Low Cost ◽  
Content Type ◽  
Customer Base ◽  
Pertinent Information ◽  
The Right ◽  
Practical Implications

Purpose Reviews the latest management developments across the globe and pinpoints practical implications from cutting-edge research and case studies. Design/methodology/approach This briefing is prepared by an independent writer who adds their own impartial comments and places the articles in context. Findings Developing a feeling of authenticity about products amongst the target customer base is an essential goal for marketers even in terms of low cost items. Consumers derive information from a broad range of marketing communications and consistency is a key element for success. Originality/value The briefing saves busy executives and researchers hours of reading time by selecting only the very best, most pertinent information and presenting it in a condensed and easy-to-digest format.

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