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

Layout understanding : a knowledge-based approach

Thesis (M.S.)--Massachusetts Institute of Technology, Program in Media Arts & Sciences, 1994.Includes bibliographical references (leaves 50-53).by Bagepalli C. Krishna.M.S

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

Inferring Constraints from Multiple Snapshots

Many graphics tasks, such as the manipulation of graphical objects, and the construction of user-interface widgets, can be facilitated by geometric constraints. However, the difficulty of specifying constraints by traditional methods forms a barrier to their widespread use. In order to make constraints easier to declare, we have developed a method of specifying constraints implicitly, through multiple examples. Snapshots are taken of an initial scene configuration, and one or more additional snapshots are taken after the scene has been edited into other valid configurations. The constraints that are satisfied in all the snapshots are then applied to the scene objects. We discuss an efficient algorithm for inferring constraints from multiple snapshots. The algorithm has been incorporated into the Chimera editor, and several examples of its use are discussed

How people visually represent discrete constraint problems

Problems such as timetabling or personnel allocation can be modeled and solved using discrete constraint programming languages. However, while existing constraint solving software solves such problems quickly in many cases, these systems involve specialized languages that require significant time and effort to learn and apply. These languages are typically text-based and often difficult to interpret and understand quickly, especially for people without engineering or mathematics backgrounds. Visualization could provide an alternative way to model and understand such problems. Although many visual programming languages exist for procedural languages, visual encoding of problem specifications has not received much attention. Future problem visualization languages could represent problem elements and their constraints unambiguously, but without unnecessary cognitive burdens for those needing to translate their problem's mental representation into diagrams.As a first step towards such languages, we executed a study that catalogs how people represent constraint problems graphically. We studied three groups with different expertise: non-computer scientists, computer scientists and constraint programmers and analyzed their marks on paper (e.g., arrows), gestures (e.g., pointing) and the mappings to problem concepts (e.g., containers, sets). We provide foundations to guide future tool designs allowing people to effectively grasp, model and solve problems through visual representations

Storyboard programming of data structure manipulations : a picture is worth 20 lines of code

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Includes bibliographical references (p. 67-69).We introduce Storyboard Programming, a new programming model that harnesses the programmer's visual intuition about a problem to synthesize a correct implementation. The motivation for our technique comes from the domain of data-structure manipulations. In this domain, programmers often think in terms of abstract graphical visualizations but have a hard time translating that intuition into low-level pointer manipulating code. We aim to bridge this gap and show that it is possible to derive the low-level implementation automatically from the graphical specifications with little additional input from the programmer. The storyboard in our programming model consists of a series of scenarios which show how the data-structure evolves under different conditions. We present two novel algorithms to synthesize the code from the storyboards. The algorithms derive an abstract domain and a set of correctness conditions automatically from the storyboards. The synthesizer uses the abstract domain to perform abstraction guided combinatorial synthesis. The resulting program is guaranteed to satisfy the correctness conditions derived from the storyboard, and to conform to the high-level structure specified by the programmer. We have implemented our framework successfully on top of the SKETCH system. Our implementation is capable of synthesizing several interesting data-structure manipulations such as insertion, deletion, rotation, reversal over linked list and binary search tree data structures.by Rishabh Singh.S.M

Specification-driven design

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1990.Includes bibliographical references (leaves 144-151).by Nayel Salah el-Schafei.Ph.D

Highly Interactive Web-Based Courseware

Zukünftige Lehr-/Lernprogramme sollen als vernetzte Systeme die Lernenden befähigen, Lerninhalte zu erforschen und zu konstruieren, sowie Verständnisschwierigkeiten und Gedanken in der Lehr-/Lerngemeinschaft zu kommunizieren. Lehrmaterial soll dabei in digitale Lernobjekte übergeführt, kollaborativ von Programmierern, Pädagogen und Designern entwickelt und in einer Datenbank archiviert werden, um von Lehrern und Lernenden eingesetzt, angepasst und weiterentwickelt zu werden. Den ersten Schritt in diese Richtung machte die Lerntechnologie, indem sie Wiederverwendbarkeit und Kompabilität für hypermediale Kurse spezifizierte. Ein größeres Maß an Interaktivität wird bisher allerdings noch nicht in Betracht gezogen. Jedes interaktive Lernobjekt wird als autonome Hypermedia-Einheit angesehen, aufwändig in der Erstellung, und weder mehrstufig verschränk- noch anpassbar, oder gar adäquat spezifizierbar. Dynamische Eigenschaften, Aussehen und Verhalten sind fest vorgegeben. Die vorgestellte Arbeit konzipiert und realisiert Lerntechnologie für hypermediale Kurse unter besonderer Berücksichtigung hochgradig interaktiver Lernobjekte. Innovativ ist dabei zunächst die mehrstufige, komponenten-basierte Technologie, die verschiedenste strukturelle Abstufungen von kompletten Lernobjekten und Werkzeugsätzen bis hin zu Basiskomponenten und Skripten, einzelnen Programmanweisungen, erlaubt. Zweitens erweitert die vorgeschlagene Methodik Kollaboration und individuelle Anpassung seitens der Teilnehmer eines hypermedialen Kurses auf die Software-Ebene. Komponenten werden zu verknüpfbaren Hypermedia-Objekten, die in der Kursdatenbank verwaltet und von allen Kursteilnehmern bewertet, mit Anmerkungen versehen und modifiziert werden. Neben einer detaillierten Beschreibung der Lerntechnologie und Entwurfsmuster für interaktive Lernobjekte sowie verwandte hypermediale Kurse wird der Begriff der Interaktivität verdeutlicht, indem eine kombinierte technologische und symbolische Definition von Interaktionsgraden vorgestellt und daraus ein visuelles Skriptschema abgeleitet wird, welches Funktionalität übertragbar macht. Weiterhin wird die Evolution von Hypermedia und Lehr-/Lernprogrammen besprochen, um wesentliche Techniken für interaktive, hypermediale Kurse auszuwählen. Die vorgeschlagene Architektur unterstützt mehrsprachige, alternative Inhalte, bietet konsistente Referenzen und ist leicht zu pflegen, und besitzt selbst für interaktive Inhalte Online-Assistenten. Der Einsatz hochgradiger Interaktivität in Lehr-/Lernprogrammen wird mit hypermedialen Kursen im Bereich der Computergraphik illustriert.The grand vision of educational software is that of a networked system enabling the learner to explore, discover, and construct subject matters and communicate problems and ideas with other community members. Educational material is transformed into reusable learning objects, created collaboratively by developers, educators, and designers, preserved in a digital library, and utilized, adapted, and evolved by educators and learners. Recent advances in learning technology specified reusability and interoperability in Web-based courseware. However, great interactivity is not yet considered. Each interactive learning object represents an autonomous hypermedia entity, laborious to create, impossible to interlink and to adapt in a graduated manner, and hard to specify. Dynamic attributes, the look and feel, and functionality are predefined. This work designs and realizes learning technology for Web-based courseware with special regard to highly interactive learning objects. The innovative aspect initially lies in the multi-level, component-based technology providing a graduated structuring. Components range from complex learning objects to toolkits to primitive components and scripts. Secondly, the proposed methodologies extend community support in Web-based courseware – collaboration and personalization – to the software layer. Components become linkable hypermedia objects and part of the courseware repository, rated, annotated, and modified by all community members. In addition to a detailed description of technology and design patterns for interactive learning objects and matching Web-based courseware, the thesis clarifies the denotation of interactivity in educational software formulating combined levels of technological and symbolical interactivity, and deduces a visual scripting metaphor for transporting functionality. Further, it reviews the evolution of hypermedia and educational software to extract substantial techniques for interactive Web-based courseware. The proposed framework supports multilingual, alternative content, provides link consistency and easy maintenance, and includes state-driven online wizards also for interactive content. The impact of great interactivity in educational software is illustrated with courseware in the Computer Graphics domain

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