Using physically based models for collision‐sound synthesis in virtual environments

1994 ◽  
Vol 95 (5) ◽  
pp. 2967-2967 ◽  
Author(s):  
Jeng‐Feng Lee ◽  
I‐Yue Shen ◽  
John Crouch ◽  
Walt Aviles ◽  
David Zeltzer ◽  
...  
Keyword(s):  
Virtual Environments ◽  
Sound Synthesis ◽  
Physically Based ◽  
Physically Based Models

SHARP: A System for Haptic Assembly and Realistic Prototyping

2006 ◽  
Author(s):  
Abhishek Seth ◽  
Hai-Jun Su ◽  
Judy M. Vance
Keyword(s):  
Virtual Environments ◽  
Virtual Prototyping ◽  
Mechanical Assembly ◽  
Swept Volumes ◽  
Physically Based ◽  
Product Design Process ◽  
Costly Product ◽  
Easy Integration ◽  
Realization Process ◽  
Product Realization

Virtual Reality (VR) technology holds promise as a virtual prototyping tool for mechanical assembly; however, several developmental challenges still need to be addressed before virtual prototyping applications can successfully be integrated into the product realization process. This paper describes the development of SHARP (System for Haptic Assembly & Realistic Prototyping), a portable VR interface for virtual assembly. SHARP uses physically-based modeling for simulating realistic part-to-part and hand-to-part interactions in virtual environments. A dual handed haptic interface for realistic part interaction using the PHANToM® haptic devices is presented. The capability of creating subassemblies enhances the application’s ability to handle a wide variety of assembly scenarios. Swept volumes are implemented for addressing maintainability issues and a network module is added for communicating with different VR systems at dispersed geographic locations. Support for various types of VR systems allows an easy integration of SHARP into the product realization process resulting in faster product development, faster identification of assembly and design issues and a more efficient and less costly product design process.

scholarly journals On the residual strength of aging cast iron trunk mains: Physically-based models for asset failure

2016 ◽  
Vol 663 ◽  
pp. 204-212 ◽  
Author(s):  
Azadeh Fahimi ◽  
Timothy S. Evans ◽  
Jeff Farrow ◽  
David A. Jesson ◽  
Mike J. Mulheron ◽  
...  
Keyword(s):  
Cast Iron ◽  
Residual Strength ◽  
Physically Based ◽  
Physically Based Models

scholarly journals Performance of the dynamically dimensioned search algorithm: influence of parameter initialization strategy when calibrating a physically based hydrological model

2017 ◽  
Vol 49 (4) ◽  
pp. 971-988 ◽  
Author(s):  
Franck Lespinas ◽  
Ashu Dastoor ◽  
Vincent Fortin
Keyword(s):  
Search Algorithm ◽  
Low Cost ◽  
Initial Parameter ◽  
Cost Strategy ◽  
Physically Based ◽  
Physically Based Models ◽  
Calibration Solution ◽  
Low Cost Strategy ◽  
Parameter Values ◽  
Initialization Strategy

Abstract This study presents an evaluation of the performance of the dynamically dimensioned search (DDS) algorithm when calibrating the hydrological component of the Visualizing Ecosystems for Land Management Assessments (VELMA) ecohydrological model. Two calibration strategies were tested for the initial parameter values: (1) a ‘high-cost strategy’, where 100 sets of initial parameter values were randomly chosen within the overall parameter space, and (2) a ‘low-cost strategy’, where a unique set of initial parameter values was derived from the available field data. Both strategies were tested for six different values of the maximum number of model evaluations ranging between 100 and 10,000. Results revealed that DDS is able to converge rapidly to a good parameter calibration solution of the VELMA hydrological component regardless of the parameter initialization strategy used. The accuracy and convergence efficiency of the DDS algorithm were, however, slightly better for the low-cost strategy. This study suggests that initializing the parameter values of complex physically based models using information on the watershed characteristics can increase the efficiency of the automatic calibration procedures.

scholarly journals Evaluating performances of simplified physically based models for landslide susceptibility

2015 ◽  
Vol 12 (12) ◽  
pp. 13217-13256 ◽  
Author(s):  
G. Formetta ◽  
G. Capparelli ◽  
P. Versace
Keyword(s):  
Landslide Susceptibility ◽  
Goodness Of Fit ◽  
Shallow Landslides ◽  
Model Parameters ◽  
Test Case ◽  
Susceptibility Analysis ◽  
Physically Based ◽  
Private And Public ◽  
Physically Based Models

Abstract. Rainfall induced shallow landslides cause loss of life and significant damages involving private and public properties, transportation system, etc. Prediction of shallow landslides susceptible locations is a complex task that involves many disciplines: hydrology, geotechnical science, geomorphology, and statistics. Usually to accomplish this task two main approaches are used: statistical or physically based model. Reliable models' applications involve: automatic parameters calibration, objective quantification of the quality of susceptibility maps, model sensitivity analysis. This paper presents a methodology to systemically and objectively calibrate, verify and compare different models and different models performances indicators in order to individuate and eventually select the models whose behaviors are more reliable for a certain case study. The procedure was implemented in package of models for landslide susceptibility analysis and integrated in the NewAge-JGrass hydrological model. The package includes three simplified physically based models for landslides susceptibility analysis (M1, M2, and M3) and a component for models verifications. It computes eight goodness of fit indices by comparing pixel-by-pixel model results and measurements data. Moreover, the package integration in NewAge-JGrass allows the use of other components such as geographic information system tools to manage inputs-output processes, and automatic calibration algorithms to estimate model parameters. The system was applied for a case study in Calabria (Italy) along the Salerno-Reggio Calabria highway, between Cosenza and Altilia municipality. The analysis provided that among all the optimized indices and all the three models, the optimization of the index distance to perfect classification in the receiver operating characteristic plane (D2PC) coupled with model M3 is the best modeling solution for our test case.

scholarly journals Establishment of IDF-curves for precipitation in the tropical area of Central Africa - comparison of techniques and results

2004 ◽  
Vol 4 (3) ◽  
pp. 375-387 ◽  
Author(s):  
B. Mohymont ◽  
G. R. Demarée ◽  
D. N. Faka
Keyword(s):  
Return Period ◽  
Central Africa ◽  
Tropical Region ◽  
Data Sets ◽  
Physically Based ◽  
Physically Based Models ◽  
Comparison Of Techniques ◽  
Idf Curves ◽  
Intensity Duration Frequency ◽  
Technique Comparison

Abstract. The establishment of Intensity-Duration-Frequency (IDF) curves for precipitation remains a powerful tool in the risk analysis of natural hazards. Indeed the IDF-curves allow for the estimation of the return period of an observed rainfall event or conversely of the rainfall amount corresponding to a given return period for different aggregation times. There is a high need for IDF-curves in the tropical region of Central Africa but unfortunately the adequate long-term data sets are frequently not available. The present paper assesses IDF-curves for precipitation for three stations in Central Africa. More physically based models for the IDF-curves are proposed. The methodology used here has been advanced by Koutsoyiannis et al. (1998) and an inter-station and inter-technique comparison is being carried out. The IDF-curves for tropical Central Africa are an interesting tool to be used in sewer system design to combat the frequently occurring inundations in semi-urbanized and urbanized areas of the Kinshasa megapolis.

scholarly journals Calibration of physically based models: back to basics?

2003 ◽  
Vol 5 (4) ◽  
pp. 233-244 ◽  
Author(s):  
Vincent Guinot ◽  
Philippe Gourbesville
Keyword(s):  
Hydrological Model ◽  
Flash Flood ◽  
Model Parameters ◽  
Model Structure ◽  
Ungauged Catchments ◽  
Model Response ◽  
Physically Based ◽  
Physically Based Models ◽  
Extreme Hydrological Events ◽  
Main Factor

The modelling of extreme hydrological events often suffers from a lack of available data. Physically based models are the best available modelling option in such situations, as they can in principle provide answers about the behaviour of ungauged catchments provided that the geometry and the forcings are known with sufficient accuracy. The need for calibration is therefore limited. In some situations, calibration (seen as adjusting the model parameters so that they fit the calculation as closely to the measurements as possible) is impossible. This paper presents such a situation. The MIKE SHE physically based hydrological model is used to model a flash flood over a medium-sized catchment of the Mediterranean Alps (2820 km2). An examination of a number of modelling alternatives shows that the main factor of uncertainty in the model response is the model structure (what are the dominant processes). The second most important factor is the accuracy with which the catchment geometry is represented in the model. The model results exhibit very little sensitivity to the model parameters, and therefore calibration of these parameters is found to be useless.

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