Constraint-based Programming: A Survey

Report on constraint-based computer programming analyzing finite-domain and continuous-domain constraint satisfaction methods and existing systems which apply constraints to problem-solving, modeling, and simulation

VB2: an architecture for interaction in synthetic worlds

This paper describes the VB2 architecture for the construction of three-dimensional interactive applications. The system's state and behavior are uniformly represented as a network of interrelated objects. Dynamic components are modeled by active variables, while multi-way relations are modeled by hierarchical constraints. Daemons are used to sequence between system states in reaction to changes in variable values. The constraint network is efficiently maintained by an incremental constraint solver based on an enhancement of SkyBlue. Multiple devices are used to interact with the synthetic world through the use of various interaction paradigms, including immersive environments with visual and audio feedback. Interaction techniques range from direct manipulation, to gestural input and three-dimensional virtual tools. Adaptive pattern recognition is used to increase input device expressiveness by enhancing sensor data with classification information. Virtual tools, which are encapsulations of visual appearance and behavior, present a selective view of manipulated models' information and offer an interaction metaphor to control it. Since virtual tools are first class objects, they can be assembled into more complex tools, much in the same way that simple tools are built on top of a modeling hierarchy. The architecture is currently being used to build a virtual reality animation system.167-17

The XPRT Description System

This report describes research done at the Artificial Intelligence Laboratory of the Massachusetts Institute of Technology. The author was sponsored by the Institute of International Education on an ITT-fellowship.This paper introduces a frame-based description language and studies methods for reasoning about problems using knowledge expressed in the language. The system is based on the metaphor of a society of communicating experts and incorporates within this framework most of the currently known AI techniques, such as pattern-directed invocation, explicit control of reasoning, propagation of constraints, dependency recording, context mechanisms, message passing, conflict resolution, default reasoning, etc.MIT Artificial Intelligence Laboratory Institute of International Educatio

Perspektiven zur Kombination von automatischem Animationsdesign und planbasierter Hilfe

Aktuelle Themen auf dem Gebiet der intelligenten Benutzerschnittstellen behandeln derzeit die automatische Planung multimodaler Präsentationen. Hierbei stand bisher im wesentlichen die koordinierte Generierung von Text und Graphik im Vordergrund. In Zukunft wird hier aufgrund der Komplexität der zu präsentierenden Information zunehmend auch die Einbeziehung realistischer animierter 3D-Graphiken gefordert sein. Einen anderen wichtigen Forschungsschwerpunkt bildet der Einsatz graphischer Ausgabekomponenten für planbasierte Hilfesysteme. Die vorliegende Arbeit hat zum Ziel zunächst einen Überblick über den derzeitigen Stand der Forschung in diesen beiden Bereichen zu geben, als auch neue Anforderungen an die automatische Animationsgenerierung und an Systeme zur planbasierten graphischen Hilfe zu formulieren. Anschließend wollen wir, basierend auf Ergebnissen und Erfahrungen aus WIP und PLUS, Perspektiven für eine mögliche Weiterentwicklung und Integration von Techniken der Animationsplanung und graphischen Hilfe präsentieren

Design as exploring constraints

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Architecture, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCHBibliography: leaves 139-143.by Mark Donald Gross.Ph.D

Spatial contexts : an interactive environment for personal design

Thesis (M.S.V.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCHBibliography: leaves 133-140.by Jonathan Scott Linowes.M.S.V.S

Temporal constrained objects for modelling neuronal dynamics

Background Several new programming languages and technologies have emerged in the past few decades in order to ease the task of modelling complex systems. Modelling the dynamics of complex systems requires various levels of abstractions and reductive measures in representing the underlying behaviour. This also often requires making a trade-off between how realistic a model should be in order to address the scientific questions of interest and the computational tractability of the model. Methods In this paper, we propose a novel programming paradigm, called temporal constrained objects, which facilitates a principled approach to modelling complex dynamical systems. Temporal constrained objects are an extension of constrained objects with a focus on the analysis and prediction of the dynamic behaviour of a system. The structural aspects of a neuronal system are represented using objects, as in object-oriented languages, while the dynamic behaviour of neurons and synapses are modelled using declarative temporal constraints. Computation in this paradigm is a process of constraint satisfaction within a time-based simulation. Results We identified the feasibility and practicality in automatically mapping different kinds of neuron and synapse models to the constraints of temporal constrained objects. Simple neuronal networks were modelled by composing circuit components, implicitly satisfying the internal constraints of each component and interface constraints of the composition. Simulations show that temporal constrained objects provide significant conciseness in the formulation of these models. The underlying computational engine employed here automatically finds the solutions to the problems stated, reducing the code for modelling and simulation control. All examples reported in this paper have been programmed and successfully tested using the prototype language called TCOB. The code along with the programming environment are available at http://github.com/compneuro/TCOB_Neuron. Discussion Temporal constrained objects provide powerful capabilities for modelling the structural and dynamic aspects of neural systems. Capabilities of the constraint programming paradigm, such as declarative specification, the ability to express partial information and non-directionality, and capabilities of the object-oriented paradigm especially aggregation and inheritance, make this paradigm the right candidate for complex systems and computational modelling studies. With the advent of multi-core parallel computer architectures and techniques or parallel constraint-solving, the paradigm of temporal constrained objects lends itself to highly efficient execution which is necessary for modelling and simulation of large brain circuits

The algorithm designer project : a visual programming environment for data structure demonstration

Previous work on pedagogical tools for teaching students algorithms has focused on high level animations of the algorithms. This dissertation describes a tool that gives instructors the ability to pictorially demonstrate the implementation of algorithms at the data structure level.The Algorithm Designer Project explores the use of a computer as an electronic whiteboard for instruction of computer science. It improves upon the traditional physical blackboardenvironment by providing syntactic and semantic support for data structure design and algorithm demonstration. The ultimate goal of this project is to provide an attractive, easy to use, system through which users can demonstrate simple algorithms and data structures,such as those presented in data structures textbooks. The project consists of three components: Data Structure Designer, Algorithm Designer, and Rule Designer. DataStructure Designer allows users to design and customize the appearance of data structures that they intend to use to create visual programs. Concrete examples of these data structures can be placed into Algorithm Designer and directly manipulated to demonstrate algorithms.Visual programs are programs written using pictures instead of, or in conjunction with,text. Rule Designer allows the creation and manipulation of transition rules to define visual program scripts to act upon Algorithm Designer objects. The project was implemented using the Amulet toolkit and runs on Macintosh, Windows, and UNIX platforms.A key insight discovered during development of the Algorithm Designer Project was that although textbooks employ a wide variety of data structure visualizations, the differences between these visualizations can be grouped into a small number of categories. Two unique interface items were developed during the course of the research: 1) a color mapping widget interface item that provides an easy way for the user to associate a set of colors with a range of values in a data structure visualization and 2) seeds\u27\u27 and holes, a mechanism for visually identifying and supporting type-specific semantic behavior for edge-based data structures. Finally, this dissertation describes a novel use of imperative programming constructs within a pictorial rewrite rule-based scripting system and a novel use of these rules for teaching conventional imperative programming

Programming with agents new metaphors for thinking about computation

Thesis (M.S.)--Massachusetts Institute of Technology, Program in Media Arts & Sciences, 1996.Includes bibliographical references (p. [197]-206).by Michael David Travers.M.S