scholarly journals r.avaflow v1, an advanced open source computational framework for the propagation and interaction of two-phase mass flows

2016 ◽  
Author(s):  
Martin Mergili ◽  
Jan-Thomas Fischer ◽  
Julia Krenn ◽  
Shiva P. Pudasaini
Keyword(s):  
Open Source ◽  
Programming Languages ◽  
Rock Avalanche ◽  
Two Phase ◽  
Fluid Mixture ◽  
Complex Process ◽  
Process Chains ◽  
Mass Flows ◽  
Definition Of ◽  
Gis Software

Abstract. r.avaflow represents an innovative open source computational tool for routing rapid mass flows, avalanches or process chains from a defined release area down an arbitrary topography to a deposition area. In contrast to most existing computational tools, r.avaflow (i) employs a two-phase, interacting solid and fluid mixture model; (ii) is suitable for modelling more or less complex process chains and interactions; (iii) explicitly considers both entrainment and stopping i.e. the change of the basal topography; (iv) allows for the definition of multiple release masses and/or hydrographs; and (v) serves with built-in functionalities for validation, parameter optimization and sensitivity analysis. r.avaflow is freely available as a raster module of the GRASS GIS software, employing the programming languages Python and C along with the statistical software R. We exemplify the functionalities of r.avaflow by means of two sets of computational experiments: (1) generic process chains consisting in bulk mass and hydrograph release into a reservoir with entrainment of the dam and impact downstream; (2) the prehistoric Acheron rock avalanche, New Zealand. The simulation results are generally plausible for (1) and, after the optimization of two key parameters, reasonably in line with the corresponding observations for (2). However, we identify some potential to enhance the analytic and numerical concepts. Further, thorough parameter studies are necessary in order to make r.avaflow fit for reliable forward simulations of possible future mass flow events.

scholarly journals r.avaflow v1, an advanced open-source computational framework for the propagation and interaction of two-phase mass flows

2017 ◽  
Vol 10 (2) ◽  
pp. 553-569 ◽  
Author(s):  
Martin Mergili ◽  
Jan-Thomas Fischer ◽  
Julia Krenn ◽  
Shiva P. Pudasaini
Keyword(s):  
Open Source ◽  
Programming Languages ◽  
Rock Avalanche ◽  
Two Phase ◽  
Fluid Mixture ◽  
Complex Process ◽  
Process Chains ◽  
Mass Flows ◽  
Definition Of ◽  
Gis Software

Abstract. r.avaflow represents an innovative open-source computational tool for routing rapid mass flows, avalanches, or process chains from a defined release area down an arbitrary topography to a deposition area. In contrast to most existing computational tools, r.avaflow (i) employs a two-phase, interacting solid and fluid mixture model (Pudasaini, 2012); (ii) is suitable for modelling more or less complex process chains and interactions; (iii) explicitly considers both entrainment and stopping with deposition, i.e. the change of the basal topography; (iv) allows for the definition of multiple release masses, and/or hydrographs; and (v) serves with built-in functionalities for validation, parameter optimization, and sensitivity analysis. r.avaflow is freely available as a raster module of the GRASS GIS software, employing the programming languages Python and C along with the statistical software R. We exemplify the functionalities of r.avaflow by means of two sets of computational experiments: (1) generic process chains consisting in bulk mass and hydrograph release into a reservoir with entrainment of the dam and impact downstream; (2) the prehistoric Acheron rock avalanche, New Zealand. The simulation results are generally plausible for (1) and, after the optimization of two key parameters, reasonably in line with the corresponding observations for (2). However, we identify some potential to enhance the analytic and numerical concepts. Further, thorough parameter studies will be necessary in order to make r.avaflow fit for reliable forward simulations of possible future mass flow events.

scholarly journals r.avaflow & r.randomwalk: two complementary and comprehensive open source GIS simulation tools for the propagation of rapid geophysical mass flows

2016 ◽  
Author(s):  
Martin Mergili ◽  
Matthias Benedikt ◽  
Julia Krenn ◽  
Jan-Thomas Fischer ◽  
Shiva P Pudasaini
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Flow Model ◽  
Rock Avalanche ◽  
Two Phase ◽  
Simulation Tools ◽  
Physically Based ◽  
Open Source Gis ◽  
Mass Flows ◽  
Geophysical Mass Flows

We present two GIS model applications for simulating the propagation of rapid geophysical mass flows: r.avaflow employs an advanced physically-based two phase flow model intended for in-detail case studies, r.randomwalk a conceptual model suitable for studies at various scales. Both tools are implemented in open source software environments serving for the needs of both research and practice. They offer a range of visualization, validation, parameter sensitivity analysis and parameter optimization functions. Some of the key functionalities of both tools are demonstrated for the Acheron rock avalanche in New Zealand.

scholarly journals r.avaflow & r.randomwalk: two complementary and comprehensive open source GIS simulation tools for the propagation of rapid geophysical mass flows

2016 ◽  
Author(s):  
Martin Mergili ◽  
Matthias Benedikt ◽  
Julia Krenn ◽  
Jan-Thomas Fischer ◽  
Shiva P Pudasaini
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Flow Model ◽  
Rock Avalanche ◽  
Two Phase ◽  
Simulation Tools ◽  
Physically Based ◽  
Open Source Gis ◽  
Mass Flows ◽  
Geophysical Mass Flows

We present two GIS model applications for simulating the propagation of rapid geophysical mass flows: r.avaflow employs an advanced physically-based two phase flow model intended for in-detail case studies, r.randomwalk a conceptual model suitable for studies at various scales. Both tools are implemented in open source software environments serving for the needs of both research and practice. They offer a range of visualization, validation, parameter sensitivity analysis and parameter optimization functions. Some of the key functionalities of both tools are demonstrated for the Acheron rock avalanche in New Zealand.

scholarly journals r.avaflow & r.randomwalk: two complementary and comprehensive open source GIS simulation tools for the propagation of rapid geophysical mass flows

2016 ◽  
Author(s):  
Martin Mergili ◽  
Matthias Benedikt ◽  
Julia Krenn ◽  
Jan-Thomas Fischer ◽  
Shiva P Pudasaini
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Flow Model ◽  
Rock Avalanche ◽  
Two Phase ◽  
Simulation Tools ◽  
Physically Based ◽  
Open Source Gis ◽  
Mass Flows ◽  
Geophysical Mass Flows

We present two GIS model applications for simulating the propagation of rapid geophysical mass flows: r.avaflow employs an advanced physically-based two phase flow model intended for in-detail case studies, r.randomwalk a conceptual model suitable for studies at various scales. Both tools are implemented in open source software environments serving for the needs of both research and practice. They offer a range of visualization, validation, parameter sensitivity analysis and parameter optimization functions. Some of the key functionalities of both tools are demonstrated for the Acheron rock avalanche in New Zealand.

scholarly journals Depth-Integrated Two-Phase Modeling of Two Real Cases: A Comparison between r.avaflow and GeoFlow-SPH Codes

2021 ◽  
Vol 11 (12) ◽  
pp. 5751
Author(s):  
Seyed Ali Mousavi Tayebi ◽  
Saeid Moussavi Tayyebi ◽  
Manuel Pastor
Keyword(s):  
Rock Avalanche ◽  
Two Phase ◽  
Simulation Code ◽  
Simulation Tools ◽  
Mesh Free ◽  
Particle Hydrodynamics ◽  
Landslide Evolution ◽  
Smoothed Particle ◽  
Hazard And Risk ◽  
Comparison Of The Results

Due to the growing populations in areas at high risk of natural disasters, hazard and risk assessments of landslides have attracted significant attention from researchers worldwide. In order to assess potential risks and design possible countermeasures, it is necessary to have a better understanding of this phenomenon and its mechanism. As a result, the prediction of landslide evolution using continuum dynamic modeling implemented in advanced simulation tools is becoming more important. We analyzed a depth-integrated, two-phase model implemented in two different sets of code to stimulate rapid landslides, such as debris flows and rock avalanches. The first set of code, r.avaflow, represents a GIS-based computational framework and employs the NOC-TVD numerical scheme. The second set of code, GeoFlow-SPH, is based on the mesh-free numerical method of smoothed particle hydrodynamics (SPH) with the capability of describing pore pressure’s evolution along the vertical distribution of flowing mass. Two real cases of an Acheron rock avalanche and Sham Tseng San Tsuen debris flow were used with the best fit values of geotechnical parameters obtained in the prior modeling to investigate the capabilities of the sets of code. Comparison of the results evidenced that both sets of code were capable of properly reproducing the run-out distance, deposition thickness, and deposition shape in the benchmark exercises. However, the values of maximum propagation velocities and thickness were considerably different, suggesting that using more than one set of simulation code allows us to predict more accurately the possible scenarios and design more effective countermeasures.

scholarly journals Options for putting CDS/ISIS databases on the internet

2006 ◽  
Vol 40 (3) ◽  
pp. 286-295 ◽  
Author(s):  
Andrew Buxton
Keyword(s):  
Open Source ◽  
Programming Languages ◽  
Operating Systems ◽  
Open Source Software ◽  
Design Methodology ◽  
The Internet ◽  
Content Type

PurposeTo review the variety of software solutions available for putting CDS/ISIS databases on the internet. To help anyone considering which route to take.Design/methodology/approachBriefly describes the characteristics, history, origin and availability of each package. Identifies the type of skills required to implement the package and the kind of application it is suited to. Covers CDS/ISIS Unix version, JavaISIS, IsisWWW, WWWISIS Versions 3 and 5, Genisis, IAH, WWW‐ISIS, and OpenIsis.FindingsThere is no obvious single “best” solution. Several are free but may require more investment in acquiring the skills to install and configure them. The choice will depend on the user's experience with CDS/ISIS formatting language, HTML, programming languages, operating systems, open source software, and so on.Originality/valueThere is detailed documentation available for most of these packages, but little previous guidance to help potential users to distinguish and choose between them.

scholarly journals Validation of Sexological Worldview

SAGE Open ◽  
2012 ◽  
Vol 2 (1) ◽  
pp. 215824401243907 ◽  
Author(s):  
Justin A. Sitron ◽  
Donald A. Dyson
Keyword(s):  
Attitude Change ◽  
Service Provision ◽  
Perspective Transformation ◽  
The United States ◽  
Qualitative Approach ◽  
Second Phase ◽  
Two Phase ◽  
Convenience Sample ◽  
Developmental Characteristics ◽  
Definition Of

The authors originally posited that a new construct must be developed to measure the success of affective training for sexologists, particularly the Sexuality Attitudes Reassessment (SAR) modality. Couching their critique in studies that have been conducted to measure the SAR’s effectiveness as a method used to evoke perspective transformation and more sensitive and humanistic service provision, the authors argued that the development of a professional’s sexological worldview would be a more accurate construct than attitude change to measure when considering the outcomes of SAR training. This study in the United States used a two-phase qualitative approach to validate the proposed sexological worldview construct. In the first phase, they surveyed a panel of 16 sexologists regarding their original proposed definition of sexological worldview and refined it. In the second phase, they completed 30 one-on-one interviews with a convenience sample of sexologists and sexology students. Using an inductive content analysis of the interview transcripts, seven themes emerged in support of the proposed definition of sexological worldview, including its components and its developmental characteristics. The article concludes with a discussion of the implications for the use of the construct for the training of sexologists.

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