The performance of an interactive graphics/computer aided design system, such as the IC layout and rule checking package implemented as part of the schematic drawing application on the Gerber Systems Technology IDS-80, is very closely related to the performance of the system's data base. This is due to the fact that most editing functions on an interactive graphics/CAD system are data base intensive functions and the data base and its management routines form one of the major building blocks of a CAD system. It can therefore be said that the performance of a CAD system is directly dependent on the data base access time and the efficiency of the managing routines. The primary objective of this project was to enhance the performance of the IC layout and rule checking package. This was done by improving the performance of the data base of the system. This was achieved by following two mutually supportive paths. The first was the transportation of the software to a new host machine which had a 32-bit processor and virtual memory capabilities. The second was to try and improve the performance of the transported data base by utilising sophisticated data base structures and memory management·techniques facilitated by the larger available memory of the new host to optimise the data base operations. The effectiveness of the two paths in achieving their respective goals was evaluated using evaluation programs which simulated characteristic data base activities.This thesis documents the above process, as well as expounds on some of the background related theory which was instrumental in the progress of the project and the drawing of the final conclusions. / Thesis (M.Sc.)-University of Natal, Durban, 1987.

Mass producing custom products requires an innovative type of manufacturing environment. Manufacturing environments at present do not possess the flexibility to generate mass produced custom products. Manufacturers’ rapid response in producing these custom products in relation to demand, yields several beneficial results from both a customer and financial perspective. Current reconfigurable manufacturing environments are yet neither financially feasible nor viable to implement. To provide a solution to the production of mass customised products, research can facilitate the development of a distinctive hybrid manufacturing cell, composed of characteristics inherent in existing manufacturing paradigms. Distinctive hybrid manufacturing cell research and development forms an environment where Computer Integrated Manufacturing (CIM) cells operate in a Reconfigurable Manufacturing environment. The development of this Hybrid Reconfigurable Computer Integrated Manufacturing (HRCIM) cell resulted in functionalities that enabled the production of mass customised products. Manufacturing characteristics of the HRCIM cell were composed of key Reconfigurable Manufacturing System (RMS) features and CIM capabilities. This project required hardware to be used in developing an integrated HRCIM cell. The cell consisted of storage systems, material handling equipment and processing stations. Specific material handling equipment was enhanced in its functionality by incorporating RMS characteristics to its existing structure. The hardware behaviour was coordinated from software. This facilitated the autonomous HRCIM cell behaviour which was derived from the mechatronic approach. The software composed of HRCIM events that were defined by its unique programming language. Highlighted software functionalities included prioritisation scheduling that resulted from customer order input. Performance data, extracted from each type of equipment, were used to parameterise a simulated HRCIM cell. During operation, the cell was frequently introduced to an irregular flow of different product geometries, which required different processing requirements. This irregularity represented mass customisation. The simulated HRCIM cell provided detailed manufacturing results. Significant results consisted of storage times, queueing times and cycle times. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.

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The mass customisation manufacturing (MCM) paradigm has created a problem in manufacturing control implementation, as each individual customer has the potential to disrupt the operations of production. The aim of this study was to characterise the manufacturing effects of customers’ decisions in product configuration, in order to research steady state control requirements and work-in-process distributions for effective MCM operations. A research method involving both analytic and empirical reasoning was used in characterising the distributed control environment of manufacturing systems involved in MCM. Sequences of job arrivals into each manufacturing system, due to customers’ decisions in product configuration, were analysed as Bernoulli processes. A customer model based on this analysis captured the correlation in product configuration decisions over time. Closed form analytic models were developed from first principles, which described the steady state behaviour of flow controlled manufacturing systems under generalised clearing policy and uncorrelated job arrival sequences. Empirical analysis of data sets achieved through discrete event simulation was used in adjusting the models to account for more complex cases involving multiple job types and varying correlation. Characteristic response surfaces were shown to exist over the domains of manufacturing system load and job arrival sequence correlation. A novel manufacturing flow control method, termed biased minimum feedback (BMF) was developed. BMF was shown to posses the capability to distribute work-in-process within the entire manufacturing facility through work-in-process regulation at each manufacturing system, so as to increase the performance of downstream assembly stations fed from parallel upstream processing stations. A case study in the production of a configurable product was used in presenting an application for the models and methods developed during this research. The models were shown to be useful in predicting steady state control requirements to increase manufacturing performance. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2013.

Transfer of information between CAD models and downstream manufacturing process planning software typically involves redundant user interaction. Many existing tools are process-centric and unsuited for selection of a "best process" in the context of existing concurrent engineering design tools. A computer based Feature-Recognition (FR) process is developed to extract critical manufacturing features from engineering product CAD models. FR technology is used for automating the extraction of data from CAD product models and uses wire-frame geometry extracted from an IGES neutral file format. Existing hint-based feature recognition techniques have been extended to encompass a broader range of manufacturing domains than typical in the literature, by utilizing a combination of algorithms, each successful at a limited range of features. Use of wire-frame models simplifies product geometry and has the potential to support rapid manufacturing shape evaluation at the conceptual design stage. Native CAD files are converted to IGES neutral files to provide geometry data marshalling to remove variations in user modelling practice, and to provide a consistent starting point for FR operations. Wire-frame models are investigated to reduce computer resources compared to surface and solid models, and provide a means to recover intellectual property in terms of manufacturing design intent from legacy and contemporary product models. Geometric ambiguity in regard to what is ?solid? and what is not has plagued wire-frame FR development in the past. A new application of crossing number theory (CNT) has been developed to solve the wire-frame ambiguity problem for a range of test parts. The CNT approach works satisfactorily for products where all faces of the product can be recovered and is tested using a variety of mechanical engineering parts. Platform independent tools like Extensible Mark-up Language are used to capture data from the FR application and provide a means to separate FR and decision support applications. Separate applications are composed of reusable software modules that may be combined as required. Combining rule-based and case-based reasoning provides decision support to the manufacturing application as a means of rejecting unsuitable processes on functional and economic grounds while retaining verifiable decision pathways to satisfy industry regulators.

Bibliography: leaves 200-207. / xi, 207 leaves : ill. ; 20 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The aim of this thesis is to design and implement the hardware mapping of critical paths of a GaAs Core Processor for a Solid Modelling Accelerator. The solid modelling accelerator is designed using GaAs/CMOS/B:CMOS unified technology. High speed GaAs technology is used in the core processor to deal with floating point intensive calculations, while CMOS technology is used where high speed outputs are not required. / Thesis (Ph.D.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 1996

Thesis (M.S.)--Ohio University, June, 2004. / Title from PDF t.p. Includes bibliographical references (leaves 96-99).

Thesis (doctoral)--Techn. Universiẗat, Darmstadt, 2003.