Shiu-Shin Lin

Integrating legacy components into a software system for storm sewer simulation

Abstract This paper presents an approach that integrates a legacy component into a software system for storm sewer simulation. The legacy component employed here is the Storm Water Management Model (SWMM). The Extended Transport (EXTRAN) block of the SWMM that applies the finite difference method (FDM) with explicit numerical schemes, solving the de Saint-Venant equations, is used to route the storm sewer flow. A storm sewer simulation system, named S4, that integrates SWMM-EXTRAN and implements a visualization model, has been developed to demonstrate the proposed approach. The approach makes use of the multi-thread technology to alternate the execution between SWMM-EXTRAN for flow simulation on one thread and the program controller that updates simulation state variables and displays the computed temporal water-stages at the junctions on the other thread at every time step of the FDM process. Two test examples are used to verify and demonstrate the feasibility of the proposed approach. The results show that the multi-thread technology is applied successfully for integrating legacy components, such as SWMM-EXTRAN, into a software system (in this case, S4). In addition, the proposed approach is generally applicable for integrating legacy models or components developed using FDM with explicit numerical schemes.

Analysis Model of Ground Vibration Propagation for High-Speed Trains

Two simple analysis models for wave propagation, the Bornitz and Wiss methods, are examined in order to evaluate their reliability in measuring ground vibrations induced by high-speed trains. First, basic soil background vibrations for various geological conditions are established. Then, field measurement data for high-speed trains on bridge and embankment structures are used to evaluate the analysis models of wave propagation. The analysis models consider the effect of the basic soil background vibration. Based on these analyses, the analysis methods of Bornitz and Wiss can be used to achieve a reasonable prediction of ground vibration attenuation for high-speed trains. Soil background vibrations exhibit relative differences in measured locations, thereby significantly affecting the ground vibration attenuation of passing high-speed trains. The attenuation coefficients of both embankment and bridge structures become larger and appear to converge in a narrow range when the basic soil background vibration is omitted, especially in embankment structures.