5396079
Fracturing Rigid Materials
We propose a novel approach to fracturing (and denting) brittle materials. To avoid the computational burden imposed by the stringent time step restrictions of explicit methods or with solving nonlinear systems of equations for implicit methods, we treat the material as a fully rigid body in the limit of infinite stiffness. In addition to a triangulated surface mesh and level set volume for collisions, each rigid body is outfitted with a tetrahedral mesh upon which finite element analysis can be carried out to provide a stress map for fracture criteria. We demonstrate that the commonly used stress criteria can lead to arbitrary fracture (especially for stiff materials) and instead propose the notion of a time averaged stress directly into the FEM analysis. When objects fracture, the virtual node algorithm provides new triangle and tetrahedral meshes in a straightforward and robust fashion. Although each new rigid body can be rasterized to obtain a new level set, small shards can be difficult to accurately resolve. Therefore, we propose a novel collision handling technique for treating both rigid bodies and rigid body thin shells represented by only a triangle mesh
18405227
Controlling fluid animation with geometric potential
We propose a new fluid control technique that uses a geometrically induced potential field. Instead of optimizing the control forces exerted at each frame, as was done in previous work, a potential is added as an extra dimension to the simulation space which coerces the fluid inside this space to form the target shape. This type of shape control requires practically no additional computing by the Navier-Stokes solver at run-time, and adds little overhead to implementation. The confinement potentials are induced from geometric information given by animators, and so the control forces that take fluids to a lower potential can be decided in a preprocessing step. We show that a slightly generalized Navier-Stokes equation for fluids in potential fields can be simulated without changing the solver itself. A harmonic potential function can be quickly found with the Poisson solver which is already implemented as a part of the Navier-Stokes solver. 2 and 3 dimensional flows designed by common methods such as hand drawing, traditional shape modeling and key-framing, can be animated efficiently with our control technique. Copyright © 2004 John Wiley & Sons, Ltd.
7007390
Wrinkled flames and cellular patterns
We model flames and fire using the Navier-Stokes equations combined with the level set method and jump conditions to model the reaction front. Previous works modeled the flame using a combination of propagation in the normal direction and a curvature term which leads to a level set equation that is parabolic in nature and thus overly dissipative and smooth. Asymptotic theory shows that one can obtain more interesting velocities and fully hyperbolic (as opposed to parabolic) equations for the level set evolution. In particular, researchers in the field of detonation shock dynamics (DSD) have derived a set of equations which exhibit characteristic cellular patterns. We show how to make use of the DSD framework in the context of computer graphics simulations of flames and fire to obtain interesting features such as flame wrinkling and cellular patterns.
13982146
Interaction Translation Methods for XML/SNMP Gateway
XML-based network management has been proposed as an alternative or to complement SNMP-based network management. But the XML-based network management does not yet provide a method to manage networks equipped with legacy SNMP agents in the integrated management system. This integrated management system must include an XML/SNMP gateway, which translates and relays messages between the XML-based manager and the SNMP agent. In this paper, we propose three methods for interaction translation in the gateway. First, we propose a DOM-based translation, which provides a method for XML-based manager to directly access management information through the standard DOM interfaces. Second, we propose an HTTP-based translation using URI extenstion with XPath and XQuery. Finally, we apply SOAP, which is accepted as a standard protocol for XML, and propose a translation method for the gateway to advertise the translation services to the manager using SOAP RPC. We also compare the advantages and disadvantages of the proposed translation methods.
61401453
Development of SNMP-XML translator and gateway for XML-based integrated network management
The research objective of our work is to develop a SNMP MIB to XML translation algorithm and to implement an SNMP-XML gateway using this algorithm. The gateway is used to transfer management information between an XML-based manager and SNMP-based agents. SNMP is widely used for Internet management, but SNMP is insufficient to manage continuously expanding networks because of constraints in scalability and efficiency. XML based network management architectures are newly proposed as alternatives to SNMP-based network management, but the XML-based Network Management System (XML-based NMS) cannot directly manage legacy SNMP agents. We also implemented an automatic specification translator (SNMP MIB to XML Translator) and an SNMP-XML gateway.
14840492
Towards Reusable Colored Petri Nets
Reuse has long been recognized as a key technology that can bring about signi cant productivity gains in software development. Code-level reuse is wellunderstood and frequently practiced. However, reuse in software requirements, another phase where much bene t can be expected, remains inadequately addressed. Hierarchical Colored Petri Net (HCPN) formalism has been successfully used on several large-scale industrial projects, and it includes features designed to enhance modularity and understandability of the model. Unfortunately, such features fall short of making HCPN reusable. In this paper, we provide formal de nitions of RCPN as a reuse extension to the HCPN. RCPN can reduce complexity and cost of modeling and analysis in requirements engineering phase and increase software development productivity. We demonstrate an application of RCPN by demonstrating how a RCPN component for water level monitoring system (WLMS) can be reused in a co ee vending machine (CVM) model.
3968249
Topiary: a tool for prototyping location-enhanced applications
Location-enhanced applications use the location of people, places, and things to augment or streamline interaction. Location-enhanced applications are just starting to emerge in several different domains, and many people believe that this type of application will experience tremendous growth in the near future. However, it currently requires a high level of technical expertise to build location-enhanced applications, making it hard to iterate on designs. To address this problem we introduce Topiary, a tool for rapidly prototyping location-enhanced applications. Topiary lets designers create a map that models the location of people, places, and things; use this active map to demonstrate scenarios depicting location contexts; use these scenarios in creating storyboards that describe interaction sequences; and then run these storyboards on mobile devices, with a wizard updating the location of people and things on a separate device. We performed an informal evaluation with seven researchers and interface designers and found that they reacted positively to the concept.
795921
Marmite: Towards End-User Programming for the Web
Many information tasks on the web require users to make use of multiple websites, for both content as well as information processing or visualization features. Programmers have created "mashups," which customize or combine the functionality of multiple websites by extracting information from web pages or accessing web services APIs. Non-programmers lack the tools or skills create such customizations because of the programming obstacles involved. Marmite is a tool that empowers non-programmers to create functionality similar to those found in mashups.