9085764
Distance Field Compression
This paper compares various techniques for compressing floating point distance fields. Both lossless and lossy techniques are compared against a new lossless technique. The new Vector Transform technique creates a predictor based upon a Vector Distance Transform and its suitability for distance field data sets is reported. The new technique produces a lossless encoding at a third of the file size of entropy encoders, and equivalent to lossy wavelet transforms, where around 75% of the coefficients have been set to zero. The algorithm predicts each voxel value linearly based upon two previous voxels chosen from one of 13 directions which have been previously computed. Those that cannot be predicted are explicitly stored.
41482626
A New Approach to the Construction of Surfaces from Contour Data
This paper presents a new approach to the construction of a surface from a stack of contour slices. Unlike most existing methods, this new approach handles ambiguous conditions consistently without employing an algorithm to establish a correspondence between vertices on one contour and those on the next. It is easy to implement and fast to compute, requiring only basic geometric properties, namely closedness and simplicity, to be available with contour data. The advantages of this new approach have also been demonstrated with solutions to a few classical problems from the literature and some practical problems in medical imaging. It can also be applied to geographical surveying and keyframe animations.
2872475
Texturing and hypertexturing of volumetric objects
Texture mapping is an extremely powerful and flexible tool for adding complex surface detail to an object. This paper introduces a method of surface texturing and hypertexturing complex volumetric objects in real-time. We employ distance field volume representations, texture based volume rendering and procedural texturing techniques with Shader Model 2.0 flexible programmable graphics hardware. We aim to provide a flexible cross-platform, non vendor specific implementation.
18996618
The Production of Volume Data from Triangular Meshes Using Voxelisation
Voxelisation is the term given to the process of converting data from one source type into a three dimensional volume of data values. The techniques known collectively as volume visualisation can then be applied to the data in order to produce a graphical representation of the object. This paper gives a practical approach to the voxelisation of data in the form of triangular meshes, and demonstrates the use of the method on various datasets. Visualisation is achieved by a method also described in the paper.
6680702
Melting Objects
This paper describes a technique for producing realistic animations of melting objects. The work presented here introduces a method that accurately models both thermal flow and the latent heat during the phase change. The mechanism for energy transfer to the model is via both boundary conditions and radiation. Emphasis is made on accurately modelling the solid object and the method is particularly suited to rigid solids with complex surface geometry. The underlying objects are constructed using Volume Graphics modelling techniques (specifically voxelization), and a numerical simulation computes the time-dependent heat flow throughout the object. A technique for computing the phase transition is given, and details for rendering the melting objects are provided. The melting is controlled by material parameters, such as specific heat capacity, thermal conductivity, latent heat and temperature. Examples are given of melting ice and a plastic man.
1777796
A System for the Non-Linear Modelling of Deformable Procedural Shapes
This paper describes a fully interactive modelling system, which we have called ClayWorks, for defining the implicit geometry of 3D objects using parametric base primitives and deformations. The goal of this system is to provide a means for describing object data and its creation history by using a series of parametric steps that can be modified post-creation in a non-linearmanner. The advantages of this approach are that unlike other modelling approaches, it enables compact object descriptions, an intuitive modelling process, a simple approach to multiresolution objects, real-time feedback during the modelling process and a render independent object representation.
12348986
Dynamic Digital Library Construction and Configuration
This paper describes a digital library architecture and implementation that is configurable, extensible and dynamic in the way it presents content and in the services it provides. The design manifests itself as a network of modules that communicate in terms of XML messages. All modules characterize the functionality they implement in response to a “describe yourself” message, and can transform messages using XSLT to support different levels of configurability. Traditional library values such as backwards compatibility and multiplatform operation are combined with the ability to add new collections and services adaptively. The paper describes the new design and shows how it can be used to build four different digital library systems. We conclude by showing how the design fits existing interoperability frameworks.
13870178
Simplifying and improving qualified types
Qualified types provide a general framework for constrained type systems, with applications including type class overloading, subtyping and record calculi. This paper presents an extended version of the type inference algorithm used in previous work, that can take account of the satisfiability of constraints to obtain more accurate principal types. The new algorithm is obtained by adding two new rules, one for simplification and one for improvement of constraint sets. In particular, it permits a better treatment for the previously troublesome multiple parameter extensions of Haskell type classes. For example, a form of parametric type classes, proposed by Chen, Hudak and Odersky, can be viewed as a special case of this work.
3268647
A digital library of conversational expressions: helping profoundly disabled users communicate
Digital libraries are for everyone. This paper describes the development of a digital library for a user who has a profound physical disability that means she cannot communicate verbally, and cannot use conventional communication tools.
6148133
Wild Things
The children's book Where the Wild Things Are by Maurice Sendak was animated using Alice version 2.0 for an introductory undergraduate 14-week programming course at Immaculata University. Using the software development lifecycle, the designers/developers collaborated on the requirements and design phases while the implementation phase was completed individually. The animation was designed and developed with the intent of applying objectoriented principles and reusing objects where appropriate.
 Three individual scenes were created using Alice version 2.0. Upon the completion of the scenes, a screen capture tool (Hypercam2), and an audio capture tool (River Past) were used to break down the animation. Those components were synchronized using Windows Movie Maker and then the animation was converted to a Flash file.
 • Scene 1 - Tommy's Bedroom: Tommy is sent to his room and his imagination creates a jungle that grows around him.
 • Scene 2 - Sailing the Ocean: Tommy imagines sailing across the sea towards an island and encounters wild things along the way.
 • Scene 3 - An Island Encounter: Tommy reaches the island and meets the wild things only to awaken back in his bedroom as his mother calls him for dinner.
9087296
Using Types to Parse Natural Language
We describe a natural language parser that uses type information to determine the grammatical structure of simple sentences and phrases. This stands in contrast to studies of type inference where types and grammatical structure play opposite roles, the former being determined by the latter. Our parser is implemented in Haskell and is based on a linguistic theory called applicative universal grammar (AUG). Our results should be interesting to computer scientists in the way in which AUG relates to types and combinatory calculus, and to linguists in the way in which a very simple, brute force parsing strategy performs surprisingly well in both performance and accuracy.