CAD interface and framework for curve optimisation applications

Computer Aided Design is currently expanding its boundaries to include more design features in its processes. Design is identified as an iterative process converging to solutions satisfying a set of constraints. Its close relation with optimisation indicate that there is strong potential for the integration of optimisation and CAD. The problem addressed in this thesis lies in interfacing the geometric representation of design with other non-geometric aspects. The example of free-form curve modelling is taken to investigate such relationships. Assumptions are made that Optimisation is powered by Evolutionary Computing algorithms like Genetic Algorithms (GA). The geometric definition of curves is commonly supported by NURBS, whose construction constraints are defined locally at the data points. Here the NURBS formulation is used with GA in an attempt to provide complementary handles on the curves shape other than the usual data point coordinates and control points weights. Differential properties are used for optimising NURBS, Hermite interpolation allows for the definition of higher order constraints (tangent, normal, bi-normal) at data points. The assignment of parameter values at the data points, known as parameterisation also provides control of the curve’s shape. Curve optimisation is also performed at the geometric modelling level. Old mathematical theorems established by Frénet and further developed by other mathematicians provide means of defining a curve’s shape with it’s intrinsic equations. Such representation is possible by using Function Representation (F-rep) algebra available in the ACIS software. Frep allows more generic and exact means of interfacing with the curve’s geometry and new functionality for curve inspection and optimisation are proposed in this thesis. The integration of optimisation findings and CAD are documented in the definition of a framework. The framework architecture proposed reconstructs a new CAD environment from separate elements bolted together in a generic Application Programming Interface (API) named “Oli interface”. Functionality created to interface optimisation and CAD makes a requirement list of the work that both sides should undertake to achieve design optimisation in the CAD environment.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Figure

This open access book shows how figures, figuring, and configuration are used to understand complex, contemporary problems. Figures are images, numbers, diagrams, data and datasets, turns-of-phrase, and representations. Contributors reflect on the history of figures as they have transformed disciplines and fields of study, and how methods of figuring and configuring have been integral to practices of description, computation, creation, criticism and political action. They do this by following figures across fields of social science, medicine, art, literature, media, politics, philosophy, history, anthropology, and science and technology studies. Readers will encounter figures as various as Je Suis Charlie, #MeToo, social media personae, gardeners, asthmatic children, systems configuration management and cloud computing – all demonstrate the methodological utility and contemporary relevance of thinking with figures. This book serves as a critical guide to a world of figures and a creative invitation to “go figure!

Figure: Concept and Method

This open access book shows how figures, figuring, and configuration are used to understand complex, contemporary problems. Figures are images, numbers, diagrams, data and datasets, turns-of-phrase, and representations. Contributors reflect on the history of figures as they have transformed disciplines and fields of study, and how methods of figuring and configuring have been integral to practices of description, computation, creation, criticism and political action. They do this by following figures across fields of social science, medicine, art, literature, media, politics, philosophy, history, anthropology, and science and technology studies. Readers will encounter figures as various as Je Suis Charlie, #MeToo, social media personae, gardeners, asthmatic children, systems configuration management and cloud computing – all demonstrate the methodological utility and contemporary relevance of thinking with figures. This book serves as a critical guide to a world of figures and a creative invitation to “go figure!

Figure

This open access book shows how figures, figuring, and configuration are used to understand complex, contemporary problems. Figures are images, numbers, diagrams, data and datasets, turns-of-phrase, and representations. Contributors reflect on the history of figures as they have transformed disciplines and fields of study, and how methods of figuring and configuring have been integral to practices of description, computation, creation, criticism and political action. They do this by following figures across fields of social science, medicine, art, literature, media, politics, philosophy, history, anthropology, and science and technology studies. Readers will encounter figures as various as Je Suis Charlie, #MeToo, social media personae, gardeners, asthmatic children, systems configuration management and cloud computing – all demonstrate the methodological utility and contemporary relevance of thinking with figures. This book serves as a critical guide to a world of figures and a creative invitation to “go figure!

Figure: Concept and Method

This open access book shows how figures, figuring, and configuration are used to understand complex, contemporary problems. Figures are images, numbers, diagrams, data and datasets, turns-of-phrase, and representations. Contributors reflect on the history of figures as they have transformed disciplines and fields of study, and how methods of figuring and configuring have been integral to practices of description, computation, creation, criticism and political action. They do this by following figures across fields of social science, medicine, art, literature, media, politics, philosophy, history, anthropology, and science and technology studies. Readers will encounter figures as various as Je Suis Charlie, #MeToo, social media personae, gardeners, asthmatic children, systems configuration management and cloud computing – all demonstrate the methodological utility and contemporary relevance of thinking with figures. This book serves as a critical guide to a world of figures and a creative invitation to “go figure!

Lexical database enrichment through semi-automated morphological analysis

Derivational morphology proposes meaningful connections between words and is largely unrepresented in lexical databases. This thesis presents a project to enrich a lexical database with morphological links and to evaluate their contribution to disambiguation. A lexical database with sense distinctions was required. WordNet was chosen because of its free availability and widespread use. Its suitability was assessed through critical evaluation with respect to specifications and criticisms, using a transparent, extensible model. The identification of serious shortcomings suggested a portable enrichment methodology, applicable to alternative resources. Although 40% of the most frequent words are prepositions, they have been largely ignored by computational linguists, so addition of prepositions was also required. The preferred approach to morphological enrichment was to infer relations from phenomena discovered algorithmically. Both existing databases and existing algorithms can capture regular morphological relations, but cannot capture exceptions correctly; neither of them provide any semantic information. Some morphological analysis algorithms are subject to the fallacy that morphological analysis can be performed simply by segmentation. Morphological rules, grounded in observation and etymology, govern associations between and attachment of suffixes and contribute to defining the meaning of morphological relationships. Specifying character substitutions circumvents the segmentation fallacy. Morphological rules are prone to undergeneration, minimised through a variable lexical validity requirement, and overgeneration, minimised by rule reformulation and restricting monosyllabic output. Rules take into account the morphology of ancestor languages through co-occurrences of morphological patterns. Multiple rules applicable to an input suffix need their precedence established. The resistance of prefixations to segmentation has been addressed by identifying linking vowel exceptions and irregular prefixes. The automatic affix discovery algorithm applies heuristics to identify meaningful affixes and is combined with morphological rules into a hybrid model, fed only with empirical data, collected without supervision. Further algorithms apply the rules optimally to automatically pre-identified suffixes and break words into their component morphemes. To handle exceptions, stoplists were created in response to initial errors and fed back into the model through iterative development, leading to 100% precision, contestable only on lexicographic criteria. Stoplist length is minimised by special treatment of monosyllables and reformulation of rules. 96% of words and phrases are analysed. 218,802 directed derivational links have been encoded in the lexicon rather than the wordnet component of the model because the lexicon provides the optimal clustering of word senses. Both links and analyser are portable to an alternative lexicon. The evaluation uses the extended gloss overlaps disambiguation algorithm. The enriched model outperformed WordNet in terms of recall without loss of precision. Failure of all experiments to outperform disambiguation by frequency reflects on WordNet sense distinctions