The application of computer aided draughting to mechanical engineering design

Imperial Users onl

Formalizing graphical notations

The thesis describes research into graphical notations for software engineering, with a principal interest in ways of formalizing them. The research seeks to provide a theoretical basis that will help in designing both notations and the software tools that process them. The work starts from a survey of literature on notation, followed by a review of techniques for formal description and for computational handling of notations. The survey concentrates on collecting views of the benefits and the problems attending notation use in software development; the review covers picture description languages, grammars and tools such as generic editors and visual programming environments. The main problem of notation is found to be a lack of any coherent, rigorous description methods. The current approaches to this problem are analysed as lacking in consensus on syntax specification and also lacking a clear focus on a defined concept of notated expression. To address these deficiencies, the thesis embarks upon an exploration of serniotic, linguistic and logical theory; this culminates in a proposed formalization of serniosis in notations, using categorial model theory as a mathematical foundation. An argument about the structure of sign systems leads to an analysis of notation into a layered system of tractable theories, spanning the gap between expressive pictorial medium and subject domain. This notion of 'tectonic' theory aims to treat both diagrams and formulae together. The research gives details of how syntactic structure can be sketched in a mathematical sense, with examples applying to software development diagrams, offering a new solution to the problem of notation specification. Based on these methods, the thesis discusses directions for resolving the harder problems of supporting notation design, processing and computer-aided generic editing. A number of future research areas are thereby opened up. For practical trial of the ideas, the work proceeds to the development and partial implementation of a system to aid the design of notations and editors. Finally the thesis is evaluated as a contribution to theory in an area which has not attracted a standard approach

Factors shaping the evolution of electronic documentation systems

The main goal is to prepare the space station technical and managerial structure for likely changes in the creation, capture, transfer, and utilization of knowledge. By anticipating advances, the design of Space Station Project (SSP) information systems can be tailored to facilitate a progression of increasingly sophisticated strategies as the space station evolves. Future generations of advanced information systems will use increases in power to deliver environmentally meaningful, contextually targeted, interconnected data (knowledge). The concept of a Knowledge Base Management System is emerging when the problem is focused on how information systems can perform such a conversion of raw data. Such a system would include traditional management functions for large space databases. Added artificial intelligence features might encompass co-existing knowledge representation schemes; effective control structures for deductive, plausible, and inductive reasoning; means for knowledge acquisition, refinement, and validation; explanation facilities; and dynamic human intervention. The major areas covered include: alternative knowledge representation approaches; advanced user interface capabilities; computer-supported cooperative work; the evolution of information system hardware; standardization, compatibility, and connectivity; and organizational impacts of information intensive environments

Remixing physical objects through tangible tools

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2011.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. 147-164).In this document we present new tools for remixing physical objects. These tools allow users to copy, edit and manipulate the properties of one or more objects to create a new physical object. We already have these capabilities using digital media: we can easily mash up videos, music and text. However, it remains difficult to remix physical objects and we cannot access the advantages of digital media, which are nondestructive, scalable and scriptable. We can bridge this gap by both integrating 2D and 3D scanning technology into design tools and employing aordable rapid prototyping technology to materialize these remixed objects. In so doing, we hope to promote copying as a tool for creation. This document presents two tools, CopyCAD and KidCAD, the first designed for makers and crafters, the second for children. CopyCAD is an augmented Computer Numerically Controlled (CNC) milling machine which allows users to copy arbitrary real world object geometry into 2D CAD designs at scale through the use of a camera-projector system. CopyCAD gathers properties from physical objects, sketches and touch interactions directly on a milling machine, allowing novice users to copy parts of real world objects, modify them and create a new physical part. KidCAD is a sculpting interface built on top of a gel-based realtime 2.5D scanner. It allows children to stamp objects into the block of gel, which are scanned in realtime, as if they were stamped into clay. Children can use everyday objects, their hands and tangible tools to design new toys or objects that will be 3D printed. This work enables novice users to easily approach designing physical objects by copying from other objects and sketching new designs. With increased access to such tools we hope that a wide range of people will be empowered to create their own objects, toys, tools and parts.by Sean Follmer.S.M

A comparison of measurement reliability between a sonic digitizer and a tape measure on a complex three-dimensional object

Digitizers and scanners have begun to replace traditional devices for measuring three dimensional objects. However, there is a shortage of relevant research to compare digitizer tools with other measuring devices. The objective of this study was to compare the measurement reliability of a sonic digitizer to a traditional measuring tool, the tape measure, for measuring a complex, three-dimensional object. It was hypothesized that: H1 Data from measurements with the digitizer vary less than data from measurements with a tape measure at the 0.05 level of significance. H2 The data from eight complex surface measurements taken with a digitizer vary less than data from a tape measure at the 0.05 level of significance. Locations on a complex three-dimensional object which replicated a human body (a half-size dress form) were selected for measurement. Measurements were made by individuals who had experience in measuring the human body with a tape measure. The digitizer was a more reliable (i.e. showed less variability) measurement tool than a tape measure for five measurement locations on the complex object, especially for the object\u27s poorly-defined areas. Measurement data from one location with body landmarks (center front) had less variability with the tape measure than with the digitizer tool. The measurements with the two tools did not show overall differences in mean values (tool x location) when examined with a two-way analysis of variance. However, when using the Levene\u27s ANOVA Transformation, variances of location and tool by location effects were significant. Based on the statistical analysis, both hypotheses were supported by the results and were accepted

Dynamic simulation in virtual environments as an evaluation tool for architectural design

Ankara : The Department of Interior Architecture and Environmental Design and Institute of Economics and Social Sciences, Bilkent Univ., 1999.Thesis (Master's) -- Bilkent University, 1999Includes bibliographical references leaves 97-105.Prediction and evaluation of future performance of buildings are essential aspects of an efficient design process. This thesis aims to discuss dynamic simulation as a prediction and evaluation tool for architectural design. It is discussed that since buildings are living entities, whole life-cycles of buildings should be dynamically simulated in a highly visualized virtual environment to evaluate the future performance of prospective designs. The media of architectural design (traditional media: paper-based drawings and physical scale models; and digital media) are analyzed in terms of their capacity to support dynamic simulations. It is concluded that virtual reality systems and resulting virtual envu'onments are yet the best media for the dynamic simulation of building designs. Some recent applications are mentioned and some important considerations for the future use of dynamic simulations in virtual environments are presented.Taşlı, ŞuleM.S

Doctor of Philosophy

dissertationServing as a record of what happened during a scientific process, often computational, provenance has become an important piece of computing. The importance of archiving not only data and results but also the lineage of these entities has led to a variety of systems that capture provenance as well as models and schemas for this information. Despite significant work focused on obtaining and modeling provenance, there has been little work on managing and using this information. Using the provenance from past work, it is possible to mine common computational structure or determine differences between executions. Such information can be used to suggest possible completions for partial workflows, summarize a set of approaches, or extend past work in new directions. These applications require infrastructure to support efficient queries and accessible reuse. In order to support knowledge discovery and reuse from provenance information, the management of those data is important. One component of provenance is the specification of the computations; workflows provide structured abstractions of code and are commonly used for complex tasks. Using change-based provenance, it is possible to store large numbers of similar workflows compactly. This storage also allows efficient computation of differences between specifications. However, querying for specific structure across a large collection of workflows is difficult because comparing graphs depends on computing subgraph isomorphism which is NP-Complete. Graph indexing methods identify features that help distinguish graphs of a collection to filter results for a subgraph containment query and reduce the number of subgraph isomorphism computations. For provenance, this work extends these methods to work for more exploratory queries and collections with significant overlap. However, comparing workflow or provenance graphs may not require exact equality; a match between two graphs may allow paired nodes to be similar yet not equivalent. This work presents techniques to better correlate graphs to help summarize collections. Using this infrastructure, provenance can be reused so that users can learn from their own and others' history. Just as textual search has been augmented with suggested completions based on past or common queries, provenance can be used to suggest how computations can be completed or which steps might connect to a given subworkflow. In addition, provenance can help further science by accelerating publication and reuse. By incorporating provenance into publications, authors can more easily integrate their results, and readers can more easily verify and repeat results. However, reusing past computations requires maintaining stronger associations with any input data and underlying code as well as providing paths for migrating old work to new hardware or algorithms. This work presents a framework for maintaining data and code as well as supporting upgrades for workflow computations

An extended spreadsheet paradigm for data visualisation systems, and its implementation

Bibliography: leaves 139-144.We describe a data visualisation system which uses spreadsheets as its user interface metaphor. Similar systems implemented in the past were hampered by the contradiction between an imperative formula language and the declarative spreadsheet framework. We have analysed spreadsheets from a data visualisation point of view, and built a system that is an improvement over past efforts to combine spreadsheets and data visualisation. Our prototype combines the following three techniques: we store lists of values in each spreadsheet cell; we use the functional programming language Scheme as the formula language and we make use of lazy evaluation. The novel combination of these techniques makes our system consistently declarative in nature, and gives it several advantages such as small, uncluttered visual programs, the ability to deal with arbitrarily large datasets and the use of advanced functional language features