A hybrid stabilization technique for simulating water wave - Structure interaction by incompressible Smoothed Particle Hydrodynamics (ISPH) method

The Smoothed Particle Hydrodynamics (SPH) method is emerging as a potential tool for studying water wave related problems, especially for violent free surface flow and large deformation problems. The incompressible SPH (ISPH) computations have been found not to be able to maintain the stability in certain situations and there exist some spurious oscillations in the pressure time history, which is similar to the weakly compressible SPH (WCSPH). One main cause of this problem is related to the non-uniform and clustered distribution of the moving particles. In order to improve the model performance, the paper proposed an efficient hybrid numerical technique aiming to correct the ill particle distributions. The correction approach is realized through the combination of particle shifting and pressure gradient improvement. The advantages of the proposed hybrid technique in improving ISPH calculations are demonstrated through several applications that include solitary wave impact on a slope or overtopping a seawall, and regular wave slamming on the subface of open-piled structure

A New Three-Dimensional Rockfall Trajectory Simulator for Open-Pit Mines

Background. Rockfall hazards on open-pit highwalls are composed of two major associated risks, the chance of the rockfall itself and the area impacted by falling rock blocks or the runout zone. Rockfall trajectory assessment is essential for estimating consequences of such incidents. Several simulation techniques in the form of computer programs have been developed for this purpose. They are used to obtain the required basis for protection designs and safety considerations in rockfall prone areas.Innovations. In this thesis, a new three-dimensional analytical program was developed for rockfall trajectory simulation and estimating runout zones. This program is designed to effectively read and visualize topographies composed of large numbers of mesh elements. It utilizes special algorithms to enable fast and effective simulations of high-resolution terrain models. The output generated by this program includes rockfall trajectories providing bounce heights, rockfall velocities and impact locations for safety designs and rock trace maps that identify hazardous zones. Both may be used by operations management to designate safe working stations in open-pit mines.Results. The developed program was calibrated using small-scale bounce tests where a detailed study was conducted on the efficiency of the program to accurately simulate bounce heights and lengths. Moreover, the performance of the program was examined in an actual open-pit mine to highlight specific capabilities of incorporated algorithms for trajectory modeling and processing high-resolution terrain models. Based on results from the case study, the program’s modeling showed acceptable correspondence to experimental results as well as reliable performance in trajectory simulation of rockfalls in terms of time-effective analysis and reasonable outcome given assumptions and input parameters

1-Dimensional Hydraulic and Sediment Transport Modelling of an Emergency Spillway

Hydropower dams are complex structures that require a high level of safety. Systems approach and system simulation have provided new insights into evaluating dam safety. System simulation of hydropower dams requires that the physical state of the critical infrastructure be represented. A 1-dimensional hydraulic and sediment transport model was developed within HEC-RAS to address erosion in an emergency spillway for an existing system simulation model. Various inflow events were simulated, and the ensuing erosion was evaluated. A range of Manning’s roughness coefficients were tested and the sensitivity was minimal. Erosion and deposition values were not accurate but offer an understanding of the patterns and relationships with various overflow events. The model will allow for a representation of the physical state of the emergency spillway within the system simulation model for the Cheakamus Dam in British Columbia

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 324)

This bibliography lists 200 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during May, 1989. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Training of Crisis Mappers and Map Production from Multi-sensor Data: Vernazza Case Study (Cinque Terre National Park, Italy)

This aim of paper is to presents the development of a multidisciplinary project carried out by the cooperation between Politecnico di Torino and ITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action). The goal of the project was the training in geospatial data acquiring and processing for students attending Architecture and Engineering Courses, in order to start up a team of "volunteer mappers". Indeed, the project is aimed to document the environmental and built heritage subject to disaster; the purpose is to improve the capabilities of the actors involved in the activities connected in geospatial data collection, integration and sharing. The proposed area for testing the training activities is the Cinque Terre National Park, registered in the World Heritage List since 1997. The area was affected by flood on the 25th of October 2011. According to other international experiences, the group is expected to be active after emergencies in order to upgrade maps, using data acquired by typical geomatic methods and techniques such as terrestrial and aerial Lidar, close-range and aerial photogrammetry, topographic and GNSS instruments etc.; or by non conventional systems and instruments such us UAV, mobile mapping etc. The ultimate goal is to implement a WebGIS platform to share all the data collected with local authorities and the Civil Protectio

Input variable selection in time-critical knowledge integration applications: A review, analysis, and recommendation paper

This is the post-print version of the final paper published in Advanced Engineering Informatics. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2013 Elsevier B.V.The purpose of this research is twofold: first, to undertake a thorough appraisal of existing Input Variable Selection (IVS) methods within the context of time-critical and computation resource-limited dimensionality reduction problems; second, to demonstrate improvements to, and the application of, a recently proposed time-critical sensitivity analysis method called EventTracker to an environment science industrial use-case, i.e., sub-surface drilling. Producing time-critical accurate knowledge about the state of a system (effect) under computational and data acquisition (cause) constraints is a major challenge, especially if the knowledge required is critical to the system operation where the safety of operators or integrity of costly equipment is at stake. Understanding and interpreting, a chain of interrelated events, predicted or unpredicted, that may or may not result in a specific state of the system, is the core challenge of this research. The main objective is then to identify which set of input data signals has a significant impact on the set of system state information (i.e. output). Through a cause-effect analysis technique, the proposed technique supports the filtering of unsolicited data that can otherwise clog up the communication and computational capabilities of a standard supervisory control and data acquisition system. The paper analyzes the performance of input variable selection techniques from a series of perspectives. It then expands the categorization and assessment of sensitivity analysis methods in a structured framework that takes into account the relationship between inputs and outputs, the nature of their time series, and the computational effort required. The outcome of this analysis is that established methods have a limited suitability for use by time-critical variable selection applications. By way of a geological drilling monitoring scenario, the suitability of the proposed EventTracker Sensitivity Analysis method for use in high volume and time critical input variable selection problems is demonstrated.E

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 192

This bibliography lists 247 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1979