Modeling, Simulation and Visualization Methods

Like ordinary symmetries, anti-symmetries are defined by relations between function cofactors. For ordinary symmetries, two cofactors must be equal, for anti-symmetries two cofactors must be complements of one another. This paper shows that anti-symmetries can be used to improve simulation performance in the same manner as ordinary symmetries. Detailed detection, clustering and simulation algorithms are given along with a set of experimental results to demonstrate the effectiveness of the algorithms. These results show that antisymmetries can be just as effective as ordinary symmetries in enhancing simulation performance. In fact, in some cases, antisymmetries give better performance than ordinary symmetries.

Simulating fire, flames or other natural phenomena can be difficult because of the inherently complex systems used to model them, while also requiring an adequate amount of realism visually. Simulating such a system in real-time can also be a problem if the system is too large, so a parallel computing techniques can be used to good effect. Particle systems have been shown to simulate flames and fires particularly well at relatively low computational cost. We describe how a simple particle system approach can be used to simulate a fire or flame in real-time in conjunction with using data parallelization, achieving a substantial performance speed up on graphical processing units (GPUs). Using NVidia’s Compute Unified Device Architecture (CUDA) and OpenGL interoperability functionality allows for further performance increases when rendering the simulation with GPUs. Additionally, different rendering techniques are used to investigate trade-offs between performance speed and visual realism.

Sand pictures are made from a mix of coloured sands and water or oil sandwiched between two sheets of glass are a common desktop amusement. However, they also provide a good example of mixing and layering in materials science. We construct a lattice-based simulation of a sand picture based around the Kawasaki spin-exchange model with empirical couplings between cells. A Monte Carlo stochastic dynamic scheme is used to update pairs of neighboring cells using a Boltzmann like energy controlled probability process. The sand cells then diffuse around, with a preference parameter for sand to adhere to other sand cells of the same or different types. This model can be perturbed with a preferred directional gravitational force that leads to nearly correct physical phase separation of the coloured sands. The model provides a visually realistic simulation that can be rendered in real time. We implement this using Android and Java on tablet computers with inbuilt gyroscopic sensors that allow the simulated system to adapt to real gravity in interactive time. We describe the model and the implementation and software architecture for this App and the associated performance tradeoffs. We discuss possible future performance improvements using graphical processing units and other tablet specific features.

Many simulation software tools do not have arbitrary precision. This paper shows a way to increase the precision for multiplication of large numbers. This paper uses several tools from number theory together to provide a solution. The front part of the product (the most significant digits) is determined using a separate algorithm from the one used to determine the tail (the least significant digits). The least significant digits are determined by applying mod 10M iteratively to the product of the tails of the two numbers input to the product. The most and the least significant bits are concatenated together to form the output product. Casting out nines is used to check the result.

We present a fast and straightforward Eulerian technique to simulate fluid flows on three-dimensional parameterized structured grids. The method’s primary design goal is the correct and efficient handling of fluid interactions with curved boundary walls and internal obstacles. This is accomplished by the use of per-cell Jacobian matrices to relate field derivatives in the world and parameter spaces, which allows us to solve the Navier-Stokes equations directly in the latter, where the domain discretization becomes a uniform grid. We describe how to apply Jacobian matrices to each step of a standard regular-grid-based simulator, including the solution of Poisson equations using both Jacobi iterations and a Biconjugate Gradient Stabilized sparse matrix solver. The technique is implemented efficiently in the CUDA programming language and takes full advantage of the massively parallel architecture of graphics cards.

 The numerical simulation such as Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) have been used in engineering design, optimization and troubleshooting. The visualization of numerical simulation results, however, is normally limited to 2D screens. Work has already been accomplished to integrate CFD results with 3D Virtual Reality (VR) visualization. This paper discusses how these previous efforts are being combined into a user-friendly software package named Center for Innovation through Visualization (CIVS) 3D-Immersive Data Visualization (3DIDV) that simplifies the process of combining and interacting numerical results, scientific rendering, and photorealistic rendering in a virtual environment. The simulation results are intuitive to experts and non-experts by using the 3D-IDV software package. The 3D-IDV software package significantly enhanced the post possessing and the accessibility of simulation results.

In this paper, the robust synchronization problem of a uncertain complex dynamical network with Markovian jumping topology via pinning sampled-data control is investigated. In order to make full use of the sawtooth structure characteristic of the sampling input delay, a discontinuous Lyapunov functional is used based on the Extended Wirtinger Inequality. By utilizing Finsler’s lemma, a new stability condition is obtained in terms of linear matrix inequalities (LMIs) for the synchronization.

Cellular Automata (CAs) are often used to simulate complex systems. One such application of a CA is to simulate the spread of disease through a susceptible population. This paper describes EpiViz, a CA-based epidemic simulator which uses a variety of input parameters, such as probability of infection, infectious period, vaccination rate, mode of infection, and probability of recovery to influence the resulting state of each entity in a CA over the course of a simulated disease outbreak. EpiViz then produces an animated representation of the outbreak. EpiViz allows a user to set disease related parameters prior to running a simulation to enable experimentation with various disease factors and to observe the effects on a susceptible population. Incorporating the traditional Susceptible-Infected-Removed (SIR) disease model, EpiViz is able to visually display an outbreak on a day-to-day basis.

As organization networks grow, it is essential that network administrators have knowledge of the different types of traffic traversing their networks and the methods of monitoring such traffic. Traffic monitoring and analysis is essential in order to troubleshoot and resolve issues as they occur in order not to bring the network to a total collapse. There are numerous tools and methods available for network traffic monitoring and analysis, no administrator can effectively carry out such activities without in-depth knowledge of the traffic on the network. The inefficient management of the network traffic may result into network collapse or degradation and these may negatively affect the network performance of the Corporate or University networks. This paper therefore, proposed a developed network topology and simulation to monitor the network performance. Therefore, achieving an effective management and controlling of the increase traffic flows in the network. The result obtained shows a better network performance in the bandwidth usage and utilization of the University network.

This project is directly attached to the challenge in the aerospace industry to meet the new environmental requirements as the Kyoto Protocol

Prism elements arise in some printed circuit board modeling contexts, such as visualization and electromagnetic field modeling. Here we consider prisms built by extruding from triangular bases which result from constrained 2d Delaunay triangulation. The goal is to partition each extruded prism into sub-prisms of high quality that fit within the given printed circuit board layers. A prism quality measure is introduced and, from it, optimal prism height is derived given a triangular base. Given a printed circuit board’s layer heights and optimal prism heights, we provide a method for determining the height of each prism element. The overall prism mesh quality is evaluated, which examines the tradeoff of prism element quality versus the number of elements. The new method also compares favorably with respect to a prior prism mesh generation method that does not involve optimizing prism heights.

Model-based testing is a technique which has been practiced by many software test teams. A prototype has been developed as a proof of concept (POC) for a User Interface (UI) application by many of the development teams. A combination of the two gives the project teams a capability to virtually work on an IT UI application at the early stage of design purely based on the function specification and come up with a solution with high confidence from both sides of development and quality assurance

This paper presents The parallel Coordinates Automated Living Context-Awareness Visualization (PCALCAV). The system applies to the maintenance of health care for disabled/elderly people by monitoring their health status and their caretakers activities daily routines in their own environment.

Modelling realistic scenes and rendering them appropriately are two key aspects of modern computer games. Scenes need to be detailed, realistically non-repetitive and computationally feasible. Procedural generation involves encoding a game scene as a recipe or procedure that can be generated and regenerated at run time, rather than just loaded from file or network server. Procedural generation in the context of web games and systems is particularly powerful in reducing bandwidth transfer requirements. We describe experiments to implement a framework for procedural generation using JavaScript and modern web client software systems such as WebGL and OpenGL shader language. Our system is able to exploit available Graphical Processing Units(GPU) and is aimed at supporting existing web based graphics engines. We present some graphical results and discuss future performance and scalability issues.