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A fundamental problem in open pit mine planning is that of determining the optimum ultimate pit limits of the mine. These limits are that pit contour which is the result of extracting a volume of material which maximizes the difference between the value of extracted ore and the total extraction cost of ore and waste whilst satisfying certain practical operational requirements, such as. safe wall slopes. The determination of the optimum pit contour provides information which is essential in the evaluation of the economic potential of the mineral deposit.A number of optimization techniques have been proposed for determining the optimum pit contour. Of these techniques, those based on graph theory, linear programming and dynamic programming are mathematically rigorous, but only those based on graph theory are more suited to solving the three-dimensional problem. Unfortunately, direct application of these techniques to large ore- bodies may cause considerable difficulties because of the exceptionally high demand on computer storage and time requirements. Indeed, 25 years of research effort has not satisfactorily resolved these computational problems.A major contribution of the work presented in this thesis is the successful implementation of a system of techniques to solve the graph theoretic model, particularly when applied to large ore- bodies. A measure of this success is the fact that pits, as much as seven times larger may be designed with a given amount of computer storage, at a fraction of the time required by current software packages. The solution strategy presented involves the application of a modified Dinics Maximum Flow algorithm, together with an efficient data reducing technique. Computational results of these techniques applied on data from gold producing mines in Western Australia are used to demonstrate the success of this strategy.The relationships ++ / between the rigorous pit optimization techniques are also considered in this work. In particular, the Lerchs-Grossman graph-theoret ic method is shown to be stepwise equivalent to a modified version of the Dual-Simplex Linear Programming technique and not as efficient as the Network Flow method.

This research is set in the context of a collaborative agreement between the Industrial Design Department, University of Canberra and the Faculty of Applied Art and Design at Ubon Rajathanee University in the northeast or Isan region of Thailand. In this thesis the textile production of the region was studied with an objective of evaluating the potential for product design process to positively influence production outcomes. Traditional textile production techniques could be lost because these processes are complex and slow, and the current environment, both physical and operational, is changing rapidly. Product design and the design process are relevant to the industrial development of Thailand and village textile production could benefit from structured design and manufacturing strategies that have a consumer focus and improved production outcomes. From a critical review of the relevant literature, it was found that village weavers valued the traditions of their craft and traditional patterns and colours were important in terms of cultural identity and village social organization. Product design process or more specifically, the Generic Design Process (GDP) was reviewed and a model developed that adapted the GDP to the prevailing research environment. The findings led to a program of field research including village interviews where the major issue of the devaluation of traditional natural material dyeing techniques was identified. Field experiments tested alternative dyeing techniques which were evaluated in a survey by village weavers. During the field research care was taken to adapt to the way in which village weavers lived and worked as the two activities were closely interrelated. The degree of skill and knowledge residing in the aging women, who constitute the majority of village weavers, in extensive and profound, and is often described as an example of local wisdom. The theoretical and experimental work has been related, with appropriate results and conclusions, to the potential for maintaining traditional natural dyeing processes albeit with different preservation techniques. The findings from this research suggests that product design processes are appropriate for village production and that the tradition of natural material colour dyes will survive, new colours were created and the potential for new trade in preserved colour dye products. Substantial databases of useful relevant information have been compiled and recommendations are made for future research.

Since the early 2000s, within the fields of Design and Human-Computer Interaction (HCI) an emerging body of unconventional design work has exemplified and articulated alternative and oppositional functions of design. Examples of such functions include provocatively speculating about alternative futures (speculation), questioning the status quo (critique), and debating political issues (agonism). Prominent examples of alternative and oppositional design have originated within HCI. Others have been heavily discussed, adapted, and critiqued within HCI. Alternative and oppositional designs have been presented under various names: critical design, design fiction, adversarial design, reflective design, ludic design, speculative design… At this moment the list continues to grow while examples of such work proliferate. This work collectively demonstrates the potential for design to engage concerns and goals that pivot around themes of generating radical alternatives and creating productive political, cultural, and social opposition. This thesis argues that there is a body of unconventional design work that becomes cohesive and legible when held together by themes of oppositionality and alternatives, and operating throughout these designs is a technique which I term design resistance. This thesis presents two primary contributions. The first contribution is to isolate and elaborate resistance as a design technique at work across a range of alternative and oppositional designs. I articulate how design resistance works by analyzing a series of design exemplars drawn from HCI and adjacent areas of Design. The second contribution is to extend and refine the overarching technique of design resistance through two design case studies. These design case studies serve the dual function of offering additional insight into design resistance grounded in my own design practice while concretely demonstrating new knowledge relevant to specific domains and concerns within HCI, including sustainable energy consumption and critiques of digital consumer technologies. Together these contributions provide new knowledge for (1) understanding the rise of alternative and oppositional designs, the concerns they are working to engage, and the research gaps they are working to fill, and (2) how to practice alternative and oppositional forms of design using techniques of design resistance.

Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: This dissertation presents modal-based techniques for the effective systematic design of quadruple-ridged flared horns (QRFHs) as reflector feeds for radio astronomy applications. A new excitation technique is proposed, consisting of a quadraxial line that terminates in the quad-ridges through the back lid of the QRFH, which allows for the integration with differential low-noise amplifiers. An equivalent circuit of this quadraxial feed is presented that allows fast synthesis of optimal feeding designs for QRFHs. In addition, the quadraxial feeding network suppresses higher-order modes significantly. The effect of eliminating these unwanted modes are investigated and the quadraxial feed is shown to outperform the coaxial feed in the known detrimental aspects of the QRFH – beamwidth narrowing for increased frequency, beamwidth variation over the upper bandwidth, high cross-polarisation levels, high co-polar sidelobes and variable phase centre – for the specific QRFH designs. Ridge-loaded modes are analysed and a large number of cut-off frequencies presented which are unavailable in literature. The pure-mode excitation of the quadraxial feed allows more effective control over the modal content in the QRFH. This is exploited in a proposed design technique where the cut-off frequencies throughout the horn are used to synthesise the ridge taper profile, in order to achieve the desired modal distribution in the aperture. The proposed feeding solution is compact and therefore is also attractive for use with cryocoolers, typically employed with front-end electronics in telescopes for radio astronomy. A prototype was successfully manufactured and the mechanical implementation of the quadraxial feed proved to be much more simple than that of the conventional feed – consisting of a coaxial line realised within the thin ridges. / AFRIKAANSE OPSOMMING: Hierdie proefskrif stel modus gebasseerde tegnieke voor vir die effektiewe sistematiese ontwerp van viervoud gerifte oopgesperde horings (VGOHs) as weerkaatser voere vir radio astronomie toepassings. ’n Nuwe voertegniek word voorgestel, wat bestaan uit ’n kwadraksiale lyn wat termineer in die vier riwwe deur die agterkant van die VGOH, wat die integrasie met differensiële laeruis versterkers toelaat. ’n Ekwivalente stroombaan van hierdie kwadraksiale voer word aangebied vir die vinnige sintese van optimale voer ontwerpe vir VGOHs. Boonop onderdruk die kwadraksiale voer netwerk ook beduidend hoër orde modusse. Die effek van die uitskakeling van hierdie ongewensde modusse word ondersoek en die kwadraksiale voer oortref die gedrag van die koaksiale voer in die bekende nadelige aspekte van die VGOH – bundelwydte vernouing met toenemende frekwensie, bundelwydte variasie oor die boonste bandwydte, hoë kruispolarisasie vlakke, hoë kopolarisasie sybande en wisselvallige fase senter – vir die spesifieke VGOH ontwerpe. Rifgelaaide modusse word geanaliseer en ‘n groot aantal afsnyfrekwensies word aangebied wat nie beskikbaar is in literatuur nie. Die suiwermodus opwekking van die kwadraksiale voer bied meer effektiewe beheer oor die modusinhoud in die VGOH. Hierdie aspek word benut in ‘n voorgestelde tegniek waar die afsnyfrekwensies deur die horing gebruik word om die rif tapsheid profiel te sintetiseer, sodat die gewensde modale distribusie in die stralingsvlak behaal word. Die voorgestelde voer oplossing is kompak en daarom ook aantreklik vir die gebruik met krioverkoelers, wat tipies gebruik word met die voorkant elektronika in teleskope vir radio astronomie. ‘n Prototipe was suksesvol vervaardig en die meganiese implimentasie van die kwadraksiale voer toon dat dit eenvoudiger is as met die gebruiklike koaksiale voer – wat bestaan uit ‘n koaksiale lyn bewerkstellig binne die dun riwwe.

People are increasingly concerned about online privacy and how computers collect, process, share, and store their personal information. Such concerns are understandable given the growing number of privacy invasions and the pervasiveness of information capture and sharing between IT systems. This situation has led to an increasingly regulated environment, limiting what systems may do, and what safeguards they must offer users. Privacy is an especially important concern in the fields of computer supported collaborative work (CSCW), Ubiquitous Computing, and e-commerce, where the nature of the applications often requires some information collection and sharing. In order to minimize risks to users it is essential to identify privacy problems early in the design process. Several methods and frameworks for accomplishing this have been proposed in the last decades. These frameworks, though based on hard-earned experience and great insight, have not seen widespread adoption despite the high level of interest in this topic. Part of the reason for this is likely the lack of evaluation and study of these frameworks. In our research we examine the key design and analysis frameworks and their elements, and compare these to the kinds of problems users face and are concerned with in terms of privacy. Based on this analysis of the relative strengths and weaknesses of existing design frameworks we derive a new design framework; STRAP (STRuctured Analysis of Privacy). In STRAP we combine light-weight goal-oriented analysis with heuristics to provide a simple yet effective design framework. We validate our analysis by demonstrating in a series of design experiments that STRAP is more efficient and effective than any one of the existing design frameworks, and provide quantitative and qualitative evidence of the value of using such frameworks as part of the design process.

Testing is the dominating method for quality assurance of industrial software. Despite its importance and the vast amount of resources invested, there are surprisingly limited efforts spent on testing research, and the few industrially applicable results that emerge are rarely adopted by industry. At the same time, the software industry is in dire need of better support for testing its software within the limited time available. Our aim is to provide a better understanding of how test cases are created and applied, and what factors really impact the quality of the actual test. The plethora of test design techniques (TDTs) available makes decisions on how to test a difficult choice. Which techniques should be chosen and where in the software should they be applied? Are there any particular benefits of using a specific TDT? Which techniques are effective? Which can you automate? What is the most beneficial way to do a systematic test of a system? This thesis attempts to answer some of these questions by providing a set of guidelines for test design, including concrete suggestions for how to improve testing of industrial software systems, thereby contributing to an improved overall system quality. The guidelines are based on ten studies on the understanding and use of TDTs. The studies have been performed in a variety of system domains and consider several different aspects of software test. For example, we have investigated some of the common mistakes in creating test cases that can lead to poor and costly testing. We have also compared the effectiveness of different TDTs for different types of systems. One of the key factors for these comparisons is a profound understanding of faults and their propagation in different systems. Furthermore, we introduce a taxonomy for TDTs based on their effectiveness (fault finding ability), efficiency (fault finding rate), and applicability. Our goal is to provide an improved basis for making well-founded decisions regarding software testing, together with a better understanding of the complex process of test design and test case writing. Our guidelines are expected to lead to improvements in testing of complex industrial software, as well as to higher product quality and shorter time to market.

Photonic links have been proposed to transport radio frequency (RF) signals over optical fiber. External optical modulation is commonly used in high performance RF-photonic links. The practical use of optical fiber to transport RF signals is still limited due to high RF signal loss. In order to reduce the RF signal loss, highly efficient modulators are needed. For many applications, modulators with broad bandwidths are required. However, there are applications that require only a narrow bandwidth. For these narrow-band applications, the modulation efficiency can be improved through the resonant enhancement technique at the expense of reduced bandwidth. The aim of this thesis is to investigate highly efficient Mach-Zehnder optical modulators (MZMs) on Lithium Niobate (LiNbO3) with resonant enhancement techniques for narrow-band RF-photonic applications. This work focuses in particular on analyzing the factors that affect the modulation efficiency through resonant enhancement so that the modulator electrode structure can be optimized for maximum modulation efficiency. A parameter study of the effects of the electrode characteristics on the modulation efficiency of resonantly enhanced modulators (RE-MZM) is provided. From this study, optimum design objectives are identified. Numerical optimization is employed to explore the design trade-offs so that optimal configurations can be found. A sensitivity analysis is carried out to assess the performance of optimal RE-MZMs with respect to the variations of fabrication conditions. The results of these investigations indicate that the RE-MZM with a large electrode gap is the optimal design since it provides high modulation efficiency although the inherent switching voltage is high, and is the most tolerant to the fabrication fluctuations. A highly efficient RE-MZM on X-cut LiNbO3 is practically demonstrated with the resonant enhancement factor of 5 dB when comparing to the unenhanced modulator with the same electrode structure and effective switching voltage of 2 V at 1.8 GHz. The performance of the RF-photonic link using the fabr icated RE-MZM is evaluated. Optimization of RE-MZMs for operating at millimeter-wave frequencies is also reported. Factors that limit the modulation efficiency of an RE-MZM at millimeter-wave frequencies are identified. Novel resonant structures that can overcome these limitations are proposed. Preliminary designs indicate that greatly improved modulation efficiency could be expected.

Technological advancements are reaching new milestones in modern world. The demand for innovations and discoveries in each field is growing greater. This is the challenge in front of product designers. This thesis is about designing a mechanism for a machine tool. Machining tools are used from manual lathes to modern automated Computer Numerical Control machines. Turning operation is one of the basic stages in machining workpiece. Wiper inserts are used in final stage of turning for better surface finish due to their multi-point radii. But to use efficiently, positioning tool edge is necessary. Requirements are drafted based on this objective. So, developing a mechanism to perform this function is the foundation. Understanding various concept generation techniques in design field is necessary. Such techniques are described in literature section and later applied in thesis. A systematic approach is drafted for developing concepts. Then concepts are developed using these techniques. These concepts are evaluated based on weightage criteria. Then concepts are selected for detail design and prototype manufacturing. These chosen concepts are simulated to validate and to analyse mechanical properties. It is concluded that one simple concept is better than others in performance and utility. Finally, the thoughts for future work are stated. This work provides a brief idea on approaching product development. / Tekniska framsteg når nya milstolpar i den moderna världen. Efterfrågan på innovationer och upptäckter inom varje område blir större. Detta är utmaningen för produktutvecklare. Det här examensarbetet handlar om att designa en mekanism för ett verktygsmaskin. Verktygsmaskiner används i allt från manuella svarvar till moderna automatiserade numeriskt styrda verktygsmaskin. Svarvning är ett av grundstegen i bearbetningen av ett arbetsstycke. Wiperskär används i slutskedet av svarvning för bättre ytfinish (ytfinhet) tack vare flerpunktsradier. Men för att ett wiperskär ska kunna navändas efektivt är positionering av verktygskanten nödvändigt. Krav för urformas utifrån detta mål och att utveckla en mekanism för att utföra den här funktionen är därmed grundläggande. Förståelse för olika konceptgenereringstekniker inom design är nödvändig. Sådana tekniker beskrivs i litteraturavsnittet och tillämpas senare i examensarbetet. Ett systematiskt tillvägagångssätt utarbetas för att utveckla koncepten. Sedan utvecklas koncepten med dessa tekniker. Dessa koncept utvärderas utifrån viktningskriterier. Sedan väljs koncept för detaljdesign och prototyptillverkning. Dessa valda koncept simuleras för att validera och analyseras mekaniska egenskaper. Slutsatsen är att ett enkelt koncept är bättre än andra när det gäller prestanda och nytta. Slutligen formuleras förslag på framtida arbete. Detta arbete ger inblick i hur det är att närma sig produktutveckling.

Made available in DSpace on 2016-04-15T23:44:48Z (GMT). No. of bitstreams: 5 Daniel Hummel Bittencourt1.pdf: 2684414 bytes, checksum: 6e983eb5ea777741467067adae4348a1 (MD5) Daniel Hummel Bittencourt2.pdf: 3035571 bytes, checksum: 84fddddc98b980caeae75ef7ee3ff306 (MD5) Daniel Hummel Bittencourt3.pdf: 1262558 bytes, checksum: baa2d1e6d5d05c0a07da837bfd8afba4 (MD5) Daniel Hummel Bittencourt4.pdf: 2431286 bytes, checksum: f3f43e60e295dd50c0f54d8a4df0abd9 (MD5) Daniel Hummel Bittencourt5.pdf: 2425612 bytes, checksum: fe92d4e5c06e54ef6b5090bbb6ce0774 (MD5) Previous issue date: 2007-03-08 / With the intent of better understanding and defining how large scale public spaces, in which esthetic connotation is based on form, are formed first as a concept and then physically, shall be presented in this work questions regarding the different classes of structural systems, construction materials, construction techniques, design techniques, as well as the cultural streams which have been a major influence on projects where the most representative architecture reveals itself. / Com o intuito de melhor entender e definir como se formam, física e conceitualmente, projetos públicos de grande porte cuja conotação estética está baseada na estrutura, serão apresentados neste estudo questões referentes às classes de sistemas estruturais, materiais construtivos, técnicas construtivas, técnicas projetuais, assim como as correntes culturais que influenciam e há muito vem influenciando projetos pelos quais a arquitetura mais representativa se revela.