An object-oriented programming of an explicit dynamics code: application to impact simulation

During the last fifty years, the development of better numerical methods and more powerful computers has been a major enterprise for the scientific community. Recent advances in computational softwares have lead to the possibility of solving more physical and complex problems (coupled problems, nonlinearities, high strain and high strain rate problems, etc.). The development of object-oriented programming leads to better structured codes for the finite element method and facilitates the development, the maintainability and the expandability of such codes. This paper presents an implementation in C++ of an explicit finite element program dedicated to the simulation of impacts. We first present a brief overview of the kinematics, the conservative and constitutive laws related to large deformation inelasticity. Then we present the design and the numerical implementation of some aspects developed with an emphasis on the object-oriented programming adopted. Finally, the efficiency and accuracy of the program are investigated through some benchmark tests

QuTiP: An open-source Python framework for the dynamics of open quantum systems

We present an object-oriented open-source framework for solving the dynamics of open quantum systems written in Python. Arbitrary Hamiltonians, including time-dependent systems, may be built up from operators and states defined by a quantum object class, and then passed on to a choice of master equation or Monte-Carlo solvers. We give an overview of the basic structure for the framework before detailing the numerical simulation of open system dynamics. Several examples are given to illustrate the build up to a complete calculation. Finally, we measure the performance of our library against that of current implementations. The framework described here is particularly well-suited to the fields of quantum optics, superconducting circuit devices, nanomechanics, and trapped ions, while also being ideal for use in classroom instruction.Comment: 16 pages, 12 figure

Communications software performance prediction

Software development can be costly and it is important that confidence in a software system be established as early as possible in the design process. Where the software supports communication services, it is essential that the resultant system will operate within certain performance constraints (e.g. response time). This paper gives an overview of work in progress on a collaborative project sponsored by BT which aims to offer performance predictions at an early stage in the software design process. The Permabase architecture enables object-oriented software designs to be combined with descriptions of the network configuration and workload as a basis for the input to a simulation model which can predict aspects of the performance of the system. The prototype implementation of the architecture uses a combination of linked design and simulation tools

Recent developments of MCViNE and its applications at SNS

MCViNE is an open source, object-oriented Monte Carlo neutron ray-tracing simulation software package. Its design allows for flexible, hierarchical representations of sophisticated instrument components such as detector systems, and samples with a variety of shapes and scattering kernels. Recently this flexible design has enabled several applications of MCViNE simulations at the Spallation Neutron Source (SNS) at Oak Ridge National Lab, including assisting design of neutron instruments at the second target station and design of novel sample environments, as well as studying effects of instrument resolution and multiple scattering. Here we provide an overview of the recent developments and new features of MCViNE since its initial introduction (Jiao et al 2016 Nucl. Instrum. Methods Phys. Res., Sect. A 810, 86–99), and some example applications

An object-oriented analysis technique for developing object-oriented simulations in Silk.

Simulation is very popular as an analysis tool for complex systems. A new paradigm shift towards object oriented simulations is hoping to make simulations even more powerful and accessible. However, in order for those not familiar with object oriented techniques to join this shift, methods must be developed for them to build object oriented simulations, until they acquire an understanding of this programming paradigm. This is an attempt to develop a procedure for just such novice model builders. This thesis begins with some background on object oriented paradigm concepts. It then provides an overview of several different object oriented analysis techniques and attempts to define the common steps of these approaches. Several different commercial object-oriented simulation software are described, with an in depth description of the software selected, Silk, a java based simulation software. The general object oriented analysis approach is then adapted for simulation purposes, resulting in a proposed object oriented analysis technique for developing simulations, and an example is given. Object oriented analysis techniques such as use-case modeling and noun extraction are used to identify potential objects in a discrete manufacturing system to be simulated. These objects are then mapped to existing object classes in the Silk software for final model building.Dept. of Industrial and Manufacturing Systems Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2003 .Z36. Source: Masters Abstracts International, Volume: 42-03, page: 1031. Adviser: R. S. Lashkari. Thesis (M.A.Sc.)--University of Windsor (Canada), 2003

Recent Development and Results with the MERLIN Tracking Code

MERLIN is a high performance accelerator simulation code which is used for modelling the collimation system at the LHC. It is written in extensible object-oriented C++ so new physics processes can be easily added. In this article we present recent developments needed for the Hi-Lumi LHC and future high energy colliders including FCC, such as hollow electron lenses and composite materials. We also give an overview of recent simulation work, validation against LHC data from run 1 and 2, and loss maps for Hi-Lumi LHC

Object-oriented shipboard electric power system library

The objective of this thesis is to explore the powerful capabilities of using an object-oriented modeling language to model and simulate an all electric Naval Shipboard Power System. Modelica has been used to model and simulate the shipboard power system which acts as an alternative simulation tool. The shipboard system is developed using the concept of packages. Different components like the buck converter, inverter, and AC machines have been modeled as a part of the library to develop the power system. The shipboard system has been simulated as two decoupled systems, the AC and DC systems. This research further focuses on developing a networked protection system to detect and clear faults and protect the shipboard power system from complete breakdown. A discrete supervisory controller has been designed using Petri nets as part of the protection system to control the converters and clear faults. A communication network has also been modeled for communication. Two different case studies, the open circuit test, and short circuit test were performed to test the effectiveness of the protection system and the simulation results are presented. This thesis also gives an overview of different properties of Modelica along with its advantages over other simulation tools, a detailed survey of different types of object-oriented simulation tools available, a comparison of different power electronics simulation tools, and some of the previous work done in Modelica

Automating Dynamic Decoupling in Object-Oriented Modelling and Simulation Tools

Abstract This manuscript presents a technique that allows Equationbased Object-Oriented Modelling Tools (EOOMT) to exploit Dynamic Decoupling (DD) for partitioning a complex model into "weakly coupled" submodels. This enhances simulation efficiency, and is naturally keen to parallel integration or co-simulation. After giving an overview of the problem and of related work, we propose a method to automate DD by means of a novel structural analysis of the system -called "cycle analysis" -and of a mixed-mode integration method. Also, some considerations are exposed on how the presented technique can be integrated in EOOMT, considering as representative example a Modelica translator. Simulation tests demonstrate the technique, and the realised implementation is released as free software

Introduction and application of GEANT4: A comparison of depth-dose

Title from PDF of title page viewed January 7, 2020Thesis advisor: Zhu Da-MingVitaIncludes bibliographical references (page 49-50)Thesis (M.S.)--Department of Physics and Astronomy. University of Missouri--Kansas City, 2019Geometry ANd Tracking 4 (GEANT4) is an object-oriented C++ based program that uses Monte Carlo methods to simulate the passage of particles through matter. A powerful application, GEANT4, allows the user to define variables such as material geometry, particle tracking, and detector physics. The versatility of GEANT4 has led it to be used by a diverse group of physicists in a variety of physics fields. This paper will act as a basic introduction and user guide for the first time user. In order to check the user's ability to use GEANT4 reliably, this paper will attempt to replicate select geometries from the previously published results of Carrier in his paper ``Validation of GEANT4, an object-oriented Monte Carlo Toolkit, for simulation in medical physics".Introduction -- GEANT4 past and present -- Overview of GEANT4 -- Working with GEANT4 -- Validation of GEANT4 -- Discussion -- Appendix A. Useful links -- Appendix B. Suggested reading