scholarly journals A process-based model for the definition of hydrological alert systems in landslide risk mitigation

2012 ◽  
Vol 12 (11) ◽  
pp. 3343-3357 ◽  
Author(s):  
M. Floris ◽  
A. D'Alpaos ◽  
A. De Agostini ◽  
G. Stevan ◽  
G. Tessari ◽  
...  
Keyword(s):  
Rainfall Threshold ◽  
Return Periods ◽  
Alert System ◽  
Rainfall Events ◽  
Ne Italy ◽  
Rainfall Depth ◽  
Physically Based ◽  
Physically Based Modelling ◽  
Set Up ◽  
Definition Of

Abstract. The definition of hydrological alert systems for rainfall-induced landslides is strongly related to a deep knowledge of the geological and geomorphological features of the territory. Climatic conditions, spatial and temporal evolution of the phenomena and characterization of landslide triggering, together with propagation mechanisms, are the key elements to be considered. Critical steps for the development of the systems consist of the identification of the hydrological variable related to landslide triggering and of the minimum rainfall threshold for landslide occurrence. In this paper we report the results from a process-based model to define a hydrological alert system for the Val di Maso Landslide, located in the northeastern Italian Alps and included in the Vicenza Province (Veneto region, NE Italy). The instability occurred in November 2010, due to an exceptional rainfall event that hit the Vicenza Province and the entire NE Italy. Up to 500 mm in 3-day cumulated rainfall generated large flood conditions and triggered hundreds of landslides. During the flood, the Soil Protection Division of the Vicenza Province received more than 500 warnings of instability phenomena. The complexity of the event and the high level of risk to infrastructure and private buildings are the main reasons for deepening the specific phenomenon occurred at Val di Maso. Empirical and physically-based models have been used to identify the minimum rainfall threshold for the occurrence of instability phenomena in the crown area of Val di Maso landslide, where a retrogressive evolution by multiple rotational slides is expected. Empirical models helped in the identification and in the evaluation of recurrence of critical rainfall events, while physically-based modelling was essential to verify the effects on the slope stability of determined rainfall depths. Empirical relationships between rainfall and landslide consist of the calculation of rainfall Depth-Duration-Frequency (DDF) curves, which allow one to determine rainfall depth (or intensity) as a function of duration for given return periods or probabilities of exceedance (frequencies). Physically-based modelling was performed through coupled seepage and slope stability analyses. Combining results from empirical and physically-based modelling, the minimum alert threshold for a reactivation of the phenomenon was found in rainfall cumulated up to 60 days with a return period of 2 yr. These results were used to set up a hydrological alert system based on the calibration of DDF curves which can be used as a sort of abacus to plot in real time rainfall depths and to set increasing levels of alert on the basis of the degree of exceptionality of rainfall. The alert system for Val di Maso was successfully tested by the rainfall events that produced displacements which have been recorded by extensometers placed in the crown area after the November 2010 landslide. However, further tests are recommendable to improve the process-based model that led to the implementation of the alert system. To this end, a monitoring system is currently being realized. In the near future, monitoring data will help in testing and improving landslide evolution and alert models. The proposed hydrological alert system proves to be effective mainly because it can be applied to different scales of investigation and geological and geomorphological contexts. In fact, it might also be applicable to territorial scale analyses, as showed by the brief example provided in this paper on how the alert system could be used for landslide early warning in the area surrounding Val di Maso. Furthermore, it is easy to set up. The needed components are a rain gauge station, a software that compares rainfall data to rainfall events with different return periods and degree of alert, and a transmission system of the warning levels to authorities.

scholarly journals Dependence Between Extreme Rainfall Events and the Seasonality and Bivariate Properties of Floods. A Continuous Distributed Physically-Based Approach

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1896 ◽  
Author(s):  
Gabriel-Martin ◽  
Sordo-Ward ◽  
Garrote ◽  
García
Keyword(s):  
Peak Flow ◽  
Total Duration ◽  
Weather Generator ◽  
Return Periods ◽  
Storm Events ◽  
Stochastic Weather Generator ◽  
Rainfall Events ◽  
Annual Peak ◽  
Extreme Flood ◽  
Physically Based

This paper focuses on proposing the minimum number of storms necessary to derive the extreme flood hydrographs accurately through event-based modelling. To do so, we analyzed the results obtained by coupling a continuous stochastic weather generator (the Advanced WEather GENerator) with a continuous distributed physically-based hydrological model (the TIN-based real-time integrated basin simulator), and by simulating 5000 years of hourly flow at the basin outlet. We modelled the outflows in a basin named Peacheater Creek located in Oklahoma, USA. Afterwards, we separated the independent rainfall events within the 5000 years of hourly weather forcing, and obtained the flood event associated to each storm from the continuous hourly flow. We ranked all the rainfall events within each year according to three criteria: Total depth, maximum intensity, and total duration. Finally, we compared the flood events obtained from the continuous simulation to those considering the N highest storm events per year according to the three criteria and by focusing on four different aspects: Magnitude and recurrence of the maximum annual peak-flow and volume, seasonality of floods, dependence among maximum peak-flows and volumes, and bivariate return periods. The main results are: (a) Considering the five largest total depth storms per year generates the maximum annual peak-flow and volume, with a probability of 94% and 99%, respectively and, for return periods higher than 50 years, the probability increases to 99% in both cases; (b) considering the five largest total depth storms per year the seasonality of flood is reproduced with an error of less than 4% and (c) bivariate properties between the peak-flow and volume are preserved, with an error on the estimation of the copula fitted of less than 2%.

scholarly journals Towards a definition of a real-time forecasting network for rainfall induced shallow landslides

2009 ◽  
Vol 9 (6) ◽  
pp. 2119-2133 ◽  
Author(s):  
S. Segoni ◽  
L. Leoni ◽  
A. I. Benedetti ◽  
F. Catani ◽  
G. Righini ◽  
...  
Keyword(s):  
Factor Of Safety ◽  
Soil Depth ◽  
Test Site ◽  
Shallow Landslide ◽  
Infinite Slope ◽  
Number Count ◽  
Rainfall Events ◽  
Ne Italy ◽  
Forecasting And Warning ◽  
Definition Of

Abstract. PREVIEW is an European Commission FP6 Integrated Project with the aim of developing, at an European level, innovative geo-information services for atmospheric, geophysical and man-made risks. Within this framework, the Landslides Platform Service 2 (forecasting of shallow rapid slope movements) has developed an integrated procedure for the forecasting and warning of distributed shallow landsliding to be used for civil protection purposes. The Service consists of an automated end-to-end forecasting chain which uses data from a probabilistic downscaled short-term rainfall forecast, soil saturation estimates and meteorological radar outputs. The above data are entered into a hydro-geological model that makes use of an infinite slope approach to calculate the distributed Factor of Safety over the entire basin. All outputs, and much of the input data, are shown on a WebGIS system so that end-users can interactively access and download data. A distinctive feature of the service is the use of an innovative soil depth model for predicting the distributed thickness of the regolith cover within the basin, which is one of the most important parameters controlling shallow landslide triggering. The service was developed in a pilot test site in NE Italy, the Armea basin. Validation makes use of two rainfall events: one that occurred in 2000 and a smaller, more recent event (2006) that caused fewer landslides. Rainfall data have been used to compute a distributed factor-of-safety map that has been overlaid onto the landslide inventory. Instead of a traditional validation approach based on the number count of correctly identified landslides, we carried out an alternative procedure based on the landslides area that gave outcomes which, for this preliminary stage of the research, can be considered promising.

Bias introduced in rainfall risk assessment by a rain gauges network

1998 ◽  
Vol 37 (11) ◽  
pp. 97-104
Author(s):  
L. Neppel ◽  
M. Desbordes ◽  
J. M. Masson
Keyword(s):  
Risk Assessment ◽  
Frequency Analysis ◽  
Return Period ◽  
Return Periods ◽  
Rainfall Events ◽  
Rain Gauges ◽  
Spatial Approach ◽  
Rainfall Depth ◽  
Rain Gauges Network

When large periods of observation are considered, the densest information are often a collection of the daily rain gauges network. As this information is scattered in space, the stochastic results and specially the rainfall risk assessment, are biased because of the rainfall events that are not ‘observed’ by the network. Rainfall risk can be assessed using a punctual approach with the estimation of regional return period of a punctual rainfall depth exceeding a given value, or using a spatial approach with the frequency analysis of the areas of isohyets defined at a given rain threshold τ. This last approach consists, for a given τ, in estimating the return period of isohyet areas. Using simulation, a method of unbiased rainfall risk assessment is proposed for the Languedoc-Roussillon region (France). It has been shown that the bias influence is negligible for the regional return periods of isohyet areas, for 24-hour and 48-hour duration, when compared to their confident limits. On the contrary the return periods of punctual rainfall depths above a given value are more sensitive: for values above 170 mm/24h and 270 mm/48h, the biased return periods could be up to 3 times overestimated.

Generation of Physically Based Analysis Factors to Improve Synthesis Models of Jet Engines

2005 ◽  
Author(s):  
Xavier Canalias ◽  
Frank Ko¨pf ◽  
Peter Sahm
Keyword(s):  
Engine Performance ◽  
Good Choice ◽  
Jet Engines ◽  
Analysis Method ◽  
Jet Engine ◽  
Analysis By Synthesis ◽  
Physically Based ◽  
The Common ◽  
Set Up ◽  
Definition Of

The ANalysis by SYNthesis (ANSYN) technique is a standard performance analysis method widely used in industry. It is currently used to evaluate engine performance from tests and to derive correcting factors (i.e. ANSYN factors) that modify certain parameters of the components’ characteristics in order to allow the reproduction of real engine behaviour by means of a synthesis calculation. Once they have been determined, these ANSYN factors can be implemented into the common synthesis tools to accurately predict the behaviour of the engine in non-tested conditions. The definition of how the engine synthesis will be modified to reproduce the measured cycle is called the “matching scheme”. It is the choice of the parameters that will not be modified, the ones that will be scaled and the ones that will be used as a reference. A good choice of the ANSYN factors and of the magnitudes used to tabulate them will make possible their physical interpretation and analysis, which can lead to the identification of inaccurate assumptions and phenomena that had not been accurately taken into account in the previous performance models. This understanding of their origin is a prerequisite for any improvement of the models and could lead to an enhanced process for the development of non-dimensional jet engine characteristics. In this study, a matching scheme for the RR-BR710 engine has been set up, implemented and applied. This method is an alternative to some of the currently used in the Rolls-Royce Deutschland ANSYN tools. The main goal of the present work has been the definition of a matching scheme that leads to the obtention of physically meaningful ANSYN factors. This allows their subsequent analysis and interpretation and can provide useful information on engine component operation and on the phenomena responsible for the observed deviations from predicted engine behaviour.

The specifics of mergers and acquisitions of innovative and technological companies

2020 ◽  
Vol 26 (5) ◽  
pp. 1186-1204
Author(s):  
A.V. Fedorov ◽  
Zh.S. Peredera
Keyword(s):  
Digital Technology ◽  
Comprehensive Analysis ◽  
Methodological Framework ◽  
Comparison Study ◽  
Technology Sector ◽  
Theoretical Perspectives ◽  
Innovation And Technology ◽  
Set Up ◽  
Definition Of ◽  
Traditional Approaches

Subject. The article reviews distinctions of M&A deals in innovation and technology. Objectives. We determine the specifics of innovative and technological companies and its impact on the synergy, process, finance, valuation of M&A deals. Methods. The article employs methods of generalization, comprehensive analysis, systematization, specification, comparison, study into trends and the structure. Graphics and tables are used to display the findings. Results. We conducted the content analysis of the term Mergers & Acquisitions, thus finding the divergence of foreign and the Russian approaches. We provide our own definition of the concept and analyzed the dynamics of the overall M&A market and the innovation and technological sector. The article describes operational distinctions of innovative and technological companies and compares them with conventional sectors. The article determined the specifics of synergy, process, finance, valuation of M&A deals in innovation and technology. Conclusions and Relevance. The innovation and technology sector saw M&A deals become more frequent for the recent five years. What distinguishes them is the number of startups and infant businesses, large M&A deals in order to develop their ecosystems, involve digital technology companies. Traditional approaches should be adapted for structuring M&A deals, their arrangement, financing and valuation of target companies. The findings can lay the groundwork for further studies into the specifics of the innovation and technology sector, M&A deals, and set up the methodological framework for the valuation of innovative and technological companies. The findings can also immediately support parties of M&A deals from theoretical perspectives.

Developing capital accounting practices in the integrated reporting system of agricultural organizations

2020 ◽  
Vol 23 (8) ◽  
pp. 906-921
Author(s):  
R.A. Alborov ◽  
S.M. Kontsevaya ◽  
S.V. Kozmenkova
Keyword(s):  
Original Method ◽  
Theory And Practice ◽  
Integrated Reporting ◽  
Governance System ◽  
Analysis And Synthesis ◽  
Agricultural Organizations ◽  
Set Up ◽  
Definition Of ◽  
Methodological Aspects ◽  
Agricultural Organization

Subject. This article deals with the theory-and practice-relevant issues of classification and content definition of different types of capital used as sources of operations financing, and recommendations for developing their accounting in agricultural organizations. Objectives. The article aims to substantiate the organizational and methodological aspects of capital accounting development to generate information on value reserve and creation of value as new in the organization's integrated reporting. The article also aims to define the classification and content of capital types as sources of financing for the organization's activities and develop recommendations for developing the accounting of the availability, increase, reduction or transformation of the relevant types of capital in the organization's business activities. Methods. For the study, we used the methods of analysis and synthesis, induction and deduction, analogy, and comparison. The scientific works of domestic specialists and regulations, including the International Standard on Integrated Reporting (IR) are the methodological basis of this work. Results. The article defines conceptual provisions and offers practical recommendations on the set-up and development of capital flow accounting in the corporate governance system of the agricultural organization. It clarifies the classification and economic content of capital as a source of funding for the organization's reproduction activities. The article also offers an original method of accounting for the value reserve (balances) and capital changes. Conclusions and Relevance. The practical application of the developed recommendations for value accounting and capital changes will help generate all the necessary information in the integrated reporting of the agricultural organization to assess its reserves of value, create value as new, economic, environmental, and social efficiency of the organization's activities. The results of the study can be used to develop the theory, methodology and techniques of accounting of capital types as sources of financing of value creation as a result of the agricultural organization's business activities.

scholarly journals The Sankara Nethralaya Tamil Nadu Essilor Myopia (STEM) Study—Defining a Threshold for Non-Cycloplegic Myopia Prevalence in Children

2021 ◽  
Vol 10 (6) ◽  
pp. 1215
Author(s):  
Aparna Gopalakrishnan ◽  
Jameel Rizwana Hussaindeen ◽  
Viswanathan Sivaraman ◽  
Meenakshi Swaminathan ◽  
Yee Ling Wong ◽  
...  
Keyword(s):  
Open Field ◽  
Tamil Nadu ◽  
Mean Difference ◽  
School Vision ◽  
Elite School ◽  
Prevalence Estimates ◽  
The Mean ◽  
Clinically Significant ◽  
Set Up ◽  
Definition Of

The aim of this study was to investigate the agreement between cycloplegic and non-cycloplegic autorefraction with an open-field auto refractor in a school vision screening set up, and to define a threshold for myopia that agrees with the standard cycloplegic refraction threshold. The study was conducted as part of the Sankara Nethralaya Tamil Nadu Essilor Myopia (STEM) study, which investigated the prevalence, incidence, and risk factors for myopia among children in South India. Children from two schools aged 5 to 15 years, with no ocular abnormalities and whose parents gave informed consent for cycloplegic refraction were included in the study. All the children underwent visual acuity assessment (Pocket Vision Screener, Elite school of Optometry, India), followed by non-cycloplegic and cycloplegic (1% tropicamide) open-field autorefraction (Grand Seiko, WAM-5500). A total of 387 children were included in the study, of whom 201 were boys. The mean (SD) age of the children was 12.2 (±2.1) years. Overall, the mean difference between cycloplegic and non-cycloplegic spherical equivalent (SE) open-field autorefraction measures was 0.34 D (limits of agreement (LOA), 1.06 D to −0.38 D). For myopes, the mean difference between cycloplegic and non-cycloplegic SE was 0.13 D (LOA, 0.63D to −0.36D). The prevalence of myopia was 12% (95% CI, 8% to 15%) using the threshold of cycloplegic SE ≤ −0.50 D, and was 14% (95% CI, 11% to 17%) with SE ≤ −0.50 D using non-cycloplegic refraction. When myopia was defined as SE of ≤−0.75 D under non-cycloplegic conditions, there was no difference between cycloplegic and non-cycloplegic open-field autorefraction prevalence estimates (12%; 95% CI, 8% to 15%; p = 1.00). Overall, non-cycloplegic refraction underestimates hyperopia and overestimates myopia; but for subjects with myopia, this difference is minimal and not clinically significant. A threshold of SE ≤ −0.75 D agrees well for the estimation of myopia prevalence among children when using non-cycloplegic refraction and is comparable with the standard definition of cycloplegic myopic refraction of SE ≤ −0.50 D.

scholarly journals Analysis of the development of a hydrological balance for future decades in the Senianska depression in the Eastern Slovak lowland

2010 ◽  
Vol 18 (4) ◽  
pp. 30-40 ◽  
Author(s):  
M. Tegelhoffová
Keyword(s):  
River Basin ◽  
Overland Flow ◽  
Water Levels ◽  
Water Control ◽  
Mike She ◽  
Hydrological Balance ◽  
Small Water ◽  
Model Domain ◽  
Physically Based ◽  
Set Up

Analysis of the development of a hydrological balance for future decades in the Senianska depression in the Eastern Slovak lowlandThe goal of the article was to analyze the hydrological balance for future decades in a pilot area in the Eastern Slovak lowland. The aim was to set up the physically-based Mike SHE hydrological model for the modeling hydrological balance in the selected wetland ecosystem in the Eastern Slovak Lowland. The pilot area - the Senianska depression is located near the village of Senne, between the Laborec and Uh Rivers. Specifically, it is a traditional landscape of meadows, marshes, cultivated soil, small water control structures and forests. To get a complete model set up for simulating elements of the hydrologic balance in the pilot area, it was necessary to devise a model for a larger area, which includes the pilot area - the Senianska depression. Therefore, both the Mike SHE model was set up for the Laborec River basin (a model domain of 500 × 500 m) and the Čierna voda River basin (a model domain of 100 × 100 m), for the simulation period of 1981-2007, is order to get the boundary conditions (overland flow depth, water levels, discharges and groundwater table) for the model of the pilot area. The Mike SHE model constructed for the pilot area - the Senianska depression (a model domain of 1 × 1 m) -was used to simulate the elements of the hydrological balance for the existing conditions during the simulation period of 1983-2007 and for climate scenarios for the simulation period of 1983-2100. The results of the simulated elements of the hydrological balance for the existing conditions were used for a comparison of the evolution of the hydrologic conditions in the past, for identifying wet and flooded areas and for identifying the spatial distribution of the actual evapotranspiration in the pilot area. The built-up model with setting values was used for modeling the hydrological balance in changed conditions - climate change.

scholarly journals Derivation and evaluation of landslide-triggering thresholds by a Monte Carlo approach

2014 ◽  
Vol 18 (12) ◽  
pp. 4913-4931 ◽  
Author(s):  
D. J. Peres ◽  
A. Cancelliere
Keyword(s):  
Monte Carlo ◽  
Slope Stability ◽  
Power Law ◽  
Rainfall Intensity ◽  
Antecedent Rainfall ◽  
Rainfall Events ◽  
Physically Based ◽  
Power Law Equation ◽  
Triggering Rainfall ◽  
Landslide Triggering

Abstract. Assessment of landslide-triggering rainfall thresholds is useful for early warning in prone areas. In this paper, it is shown how stochastic rainfall models and hydrological and slope stability physically based models can be advantageously combined in a Monte Carlo simulation framework to generate virtually unlimited-length synthetic rainfall and related slope stability factor of safety data, exploiting the information contained in observed rainfall records and field-measurements of soil hydraulic and geotechnical parameters. The synthetic data set, dichotomized in triggering and non-triggering rainfall events, is analyzed by receiver operating characteristics (ROC) analysis to derive stochastic-input physically based thresholds that optimize the trade-off between correct and wrong predictions. Moreover, the specific modeling framework implemented in this work, based on hourly analysis, enables one to analyze the uncertainty related to variability of rainfall intensity within events and to past rainfall (antecedent rainfall). A specific focus is dedicated to the widely used power-law rainfall intensity–duration (I–D) thresholds. Results indicate that variability of intensity during rainfall events influences significantly rainfall intensity and duration associated with landslide triggering. Remarkably, when a time-variable rainfall-rate event is considered, the simulated triggering points may be separated with a very good approximation from the non-triggering ones by a I–D power-law equation, while a representation of rainfall as constant–intensity hyetographs globally leads to non-conservative results. This indicates that the I–D power-law equation is adequate to represent the triggering part due to transient infiltration produced by rainfall events of variable intensity and thus gives a physically based justification for this widely used threshold form, which provides results that are valid when landslide occurrence is mostly due to that part. These conditions are more likely to occur in hillslopes of low specific upslope contributing area, relatively high hydraulic conductivity and high critical wetness ratio. Otherwise, rainfall time history occurring before single rainfall events influences landslide triggering, determining whether a threshold based only on rainfall intensity and duration may be sufficient or it needs to be improved by the introduction of antecedent rainfall variables. Further analyses show that predictability of landslides decreases with soil depth, critical wetness ratio and the increase of vertical basal drainage (leakage) that occurs in the presence of a fractured bedrock.

Sign in / Sign up

Export Citation Format

Share Document