No abstract available. / Thesis (M.A.)-University of KwaZulu-Natal, Durban, 2005.

This dissertation presents three different approaches to representing Regular Formal languages, i.e., regular expressions, finite acceptors and regular grammars. We define how each method is used to represent the language, and then the method for translating from one representation to another of the language. A toolkit is then presented which allows the user to input their definition of a language using any of the three models, and also allows the user to translate the representation of the language from one model to another. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pitermaritzburg, 2014.

With human society becoming increasingly computerised, the use of biometrics to automatically establish the identity of an individual is of great interest in a wide variety of applications. Facial appearance is an appealing biometric, on account of its relatively non-intrusive nature. As such, automated face recognition systems have been the subject of much research in recent years. This dissertation describes the development of a fully automatic face recognition system, and provides an analysis of its performance under various di erent operating conditions, in comparison with results published in prior literature. In addition to giving a detailed description of the mathematical underpinnings of the techniques used by the system, we discuss the practical considerations involved in implementing the described techniques. The system presented here uses the eigenface approach to representing facial features. A number of di erent recognition techniques have been implemented and evaluated. These include a number of variants of the original eigenface technique proposed by Turk and Pentland, as well as a related technique based on the probabilistic approach of Moghaddam et al. Due to the wide range of datasets used to evaluate face recognition systems in the literature, it is di cult to reliably compare the performance of di erent systems. The system described here has been tested with datasets encompassing a wide range of di erent conditions, allowing us to draw conclusions about how the characteristics of the test data a ect the results that are obtained. The performance of this system is comparable to other eigenface-based systems documented in the literature, achieving success rates in the region of 85% for large datasets under controlled conditions. However, performance was observed to degrade signi cantly when testing with more free-form images; in particular, the e ects of ageing on facial appearance were noted to cause problems for the system. This suggests that the matter of ageing is still a fruitful direction for further research. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2012.

Thesis (MSc (Computer Science))--University of Stellenbosch, 2006. / The minimization of a Finite Automaton (FA) deals with the construction of an equivalent FA with the least number of states. Traditional FAs and the minimization thereof is a well defined and researched topic within academic literature. Recently a generalized form of the FA, namely the generalized FA(*-FA), has been derived from these traditional FAs. This thesis investigates the minimization and reduction of one case of ...

Thesis (MSc (Mathematical Sciences)) University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Cellular Automata (CA) have become a popular vehicle to study complex dynamical behaviour of systems. CA can be used to model a wide variety of physical, biological, chemical and other systems. Such systems typically consist of subparts that change their state independently, based on the state of their immediate surroundings and some generally shared laws of change. When the CA approach was used to solve the LEGO construction problem, the best solution was found when using a variant of CA allowing for the clustering of cells. The LEGO construction problem concerns the optimal layout of a set of LEGO bricks. The advantages found for using the CA method with clustering in this case are the ease of implementation, the significantly smaller memory usage to previously implemented methods, and its trivial extension to construct multicoloured LEGO sculptures which were previously too complex to construct. In our research we propose to explore the definitions of clustering in CA and investigate the implementation and application of this method. We look at the ant sorting method described by Lumer and Faieta, and compare the implementation of this algorithm using regular CA as well as the clustering variation. The ant sorting model is a simple model, in which ants move randomly in space and pick up and deposit objects on the basis of local information. / AFRIKAANSE OPSOMMING: Sellulêre Outomate (SO) het ’n populêre metode geword om die komplekse dinamiese gedrag van sisteme bestudeer. SO kan gebruik word om ’n groot verskeidenheid fisiese, biologiese, chemiese en ander tipe sisteme te modelleer. Sulke sisteme bestaan tipies uit subafdelings wat, gebaseer op die status van hulle omgewing en ’n paar algemene gedeelde reëls van verandering, hulle status onafhanklik verander. Met die gebruik van die SO benadering om the LEGO konstruksieprobleem op te los, is die beste oplossing bereik deur gebruik te maak van ’n variant van SO, waar selle saamgroepeer kan word. Die LEGO konstruksieprobleem behels die optimale uitleg van ’n stel LEGO blokkies. In hierdie geval is die voordele van die SO met sel groepering die maklike implementasie, ’n beduidende kleiner geheuegebruik teenoor voorheen geïmplementeerde metodes, en die triviale uitbreiding daarvan om gekleurde LEGO beelde wat voorheen te kompleks was, te kan bou. In ons ondersoek verken ons die definisies van selgroepering in SO en ondersoek die implementasie en toepassing van die metode. Ons kyk na die miersorteringsmetode beskryf deur Lumer en Faieta, en vergelyk die implementasie van hierdie algoritme deur gewone SO asook die groeperingsvariasie te gebruik. Die miersorteringsmodel is ’n eenvoudige model waarin miere lukraak in ’n omgewing beweeg en voorwerpe optel of neersit volgens plaaslike inligting.

Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Traffic engineering determines the bandwidth allocation required to meet the traffic loads in a network. Similarly an economic market determines the resource allocation required to meet the demand for resources. The term bandwidth market denotes traffic engineering methods that use economic market methodology to determine the bandwidth allocation required to meet the traffic loads. A bandwidth market is an attractive traffic engineering method because of its distributed nature and ability to respond quickly to changes in network architecture or traffic loads. Network terminology is frequently used to define bandwidth markets. Our approach is to use the concepts of microeconomics to define a bandwidth market. The result is that our bandwidth markets are similar to economic markets, which is advantageous for applying economic principles correctly. This thesis presents the theoretical basis for two bandwidth markets. The first bandwidth market is a framework for building bandwidth markets. The second bandwidth market represents a society of cooperating individuals. The society distributes resources via a mechanism based on economic principles. An implementation of the bandwidth market is presented in the form of an optimisation algorithm, followed by its application to several test networks. We show that, in the test networks examined, the optimisation algorithm reduces the network loss. For all test networks, the network loss achieved by the optimisation algorithm compares well with the network loss achieved by a centralised optimisation algorithm. / AFRIKAANSE OPSOMMING: Verkeersingenieurswese bepaal die nodige bandwydtetoekenning om die verkeersvolume in 'n netwerk te dra. Op 'n soortgelyke wyse bepaal 'n ekonomiese mark die nodige hulpbrontoekenning om die aanvraag vir hulpbronne te bevredig. Die terme bandwydtemark stel verkeersingenieurswesetegnieke voor wat ekonomiese-mark metodes gebruik om die bandwydtetoekenning vir die verkeersvolume in 'n netwerk te bepaal. 'n Bandwydtemark is 'n aantreklike verkeersingenieurswesetegniek omdat dit verspreid van aard is en vinnig kan reageer op veranderinge in netwerk argitektuur en verkeersvolume. Netwerkterminologie word gereeld gebruik om bandwydtemarkte te definieer. Ons benadering is om mikro-ekonomiese begrippe te gebruik om 'n bandwydtemark te definieer. Die resultaat is dat ons bandwydtemarkte soortgelyk aan ekonomiese markte is, wat voordelig is vir die korrekte toepassing van ekonomiese beginsels. Hierdie tesis lê die teoretiese grondwerk vir twee bandwydtemarkte. Die eerste bandwydtemark is 'n raamwerk vir die ontwikkeling van bandwydtemarkte. Die tweede bandwydtemark stel 'n vereniging van samewerkende individue voor. Die vereniging versprei bandwydte deur middel van 'n meganisme wat gebasseer is op ekonomiese beginsels. 'n Implementasie van hierdie bandwydtemark word voorgestel in die vorm van 'n optimeringsalgoritme, gevolg deur die toepassing van die optimeringsalgoritme op 'n aantal toetsnetwerke. Ons wys dat die bandwydtemark die netwerkverlies verminder in die toetsnetwerke. In terme van netwerkverlies vaar die bandwydtemark goed vergeleke met 'n gesentraliseerde optimeringsalgoritme.

Thesis (MSc)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The science of signature verification is concerned with identifying individuals by their handwritten signatures. It is assumed that the signature as such is a unique feature amongst individuals and the creation thereof requires a substantial amount of hidden information which makes it difficult for another individual to reproduce the signature. Modern technology has produced devices which are able to capture information about the signing process beyond what is visible to the naked eye. A dynamic signature verification system is concerned with utilizing not only visible, i.e. shape related information but also invisible, hidden dynamical characteristics of signatures. These signature characteristics need to be subjected to analysis and modelling in order to automate use of signatures as an identification metric. We investigate the applicability of hidden Markov models to the problem of modelling signature characteristics and test their ability to distinguish between authentic signatures and forgeries. / AFRIKAANSE OPSOMMING: Die wetenskap van handtekeningverifikasie is gemoeid met die identifisering van individue deur gebruik te maak van hulle persoonlike handtekening. Dit berus op die aanname dat 'n handtekening as sulks uniek is tot elke individu en die generering daarvan 'n genoeg mate van verskuilde inligting bevat om die duplisering daarvan moeilik te maak vir 'n ander individu. Moderne tegnologie het toestelle tevoorskyn gebring wat die opname van eienskappe van die handtekeningproses buite die bestek van visuele waarneming moontlik maak. Dinamiese handtekeningverifikasie is gemoeid met die gebruik nie alleen van die sigbare manefestering van 'n handtekening nie, maar ook van die verskuilde dinamiese inligting daarvan om dit sodoende 'n lewensvatbare tegniek vir die identifikasie van individue te maak. Hierdie sigbare en onsigbare eienskappe moet aan analise en modellering onderwerp word in die proses van outomatisering van persoonidentifikasie deur handtekeninge. Ons ondersoek die toepasbaarheid van verskuilde Markov-modelle tot die modelleringsprobleem van handtekeningkarakteristieke en toets die vermoë daarvan om te onderskei tussen egte en vervalste handtekeninge.

Thesis (MSc)--Stellenbosch University , 1993. / ENGLISH ABSTRACT: Reactive systems are event driven state machines which usually do not terminate, but remain in perpetual interaction with their environment. Such systems usually interact 'With devices which introduce a high degree of concurrency and some real time constraints to the system. Because of the concurrent nature of reactive systems they are commonly implemented as communicating concurrent processes on one or more processors. Jeffay introduces a design paradigm which requires consumer processes to consume messages faster than they are produced by producer processes. If this is guaranteed, the real time constraints of such .. system are always met, and the correctness of the process interaction is guaranteed in terms of the message passing semantics. I developed the ESE kernel, which supports Jeffay systems by providing lightweight processes which communicate over asynchronous channels. Processes are scheduled non-preemptively according to the earliest deadline first policy when they have messages pending on their input channels. The Jeffay design method and the ESE kernel have been found to be highly suitable to implement embedded reactive systems. The general requirements of embedded reactive systems, and kernel support required by such systems, are discussed. / AFRIKAANSE OPSOMMING: Reaktiewe stelsels is toeatandsoutomate wat aangedryf word deur gebeure in hul omgewins. So 'n stelsel termineer gewoonlik nie, maar bly in 'n voortdurende wisselwerking met toestelle in sy omgewing. Toestelle in die omgewing van 'n reaktiewe stelsel veroorsaak in die algemeen 'n hoë mate van gelyklopendheid in die stelsel, en plaas gewoonlik sekere intydse beperkings op die stelsel. Gelyklopende stelsels word gewoonlik as stelsel. van kommunikerende prosesse geïmplementeer op een of meer prosessors. Jeffay beskryf 'n ontwerpsmetodologie waarvolgens die ontvanger van boodskappe hulle vinniger moet verwerk as wat die sender hulle kan stuur. Indien hierdie gedrag tussen alle pare kommunikerende prosesse gewaarborg kan word, sal die stelsel altyd sy intydse beperkings gehoorsaam, en word die korrektheid van interaksies tussen prosesse deur die semantiek van die boodskapwisseling gewaarborg. Die "ESE" bedryfstelselkern wat ek ontwikkel het, ondersteun stelsels wat ontwerp en geïmplementeer word volgens Jeffay se metode. Prosesse kommunikeer oor asinkrone kanale, en die ontvanger van die boodskap met die vroegste keertyd word altyd eerste geskeduleer. Jeffay se ontwerpsmetode en die "ESE" kern blyk in die praktyk baie geskik te wees vir reaktiewe stelsels wat as substelsels van groter stelsels uitvoer. Die vereistes van reaktiewe substelsels, en die kemondersteuning wat daarvoor nodig is, word bespreek.

Thesis (MSc)--Stellenbosch University, 1993. / ENGLISH ABSTRACT: Formal methods aim to apply the rigour of mathematical logic to the problem ofguaranteeing that the behaviour of (critical) software conforms to predetermined requirements. The application of formal methods during program construction centers around a formal specification of the required behaviour of the program. A development attempt is successful if the resulting program can be formally proven to conform to its specification. For any substantial program, this entails a great deal of effort. Thus, some research efforts have been directed at providing mechanical support for the application of formal methods to software development. E.W. Dijkstra's calculus of weakest precondition predicate transformers [39,38] represents one of the first attempts to use program correctness requirements to guide program development in a formal manner. / AFRIKAANSE OPSOMMING: Formele metodes poog om die strengheid van wiskundige logika te gebruik om te waarborg dat die gedrag van (kritiese) programmatuur voldoen aan gegewe vereistes. Die toepassing van formele metodes tydens programontwikkeling sentreer rondom a formele spesifikasie van die verlangde programgedrag. 'n Ontwikkelingspoging is suksesvol as daar formee1 bewys kan word dat die resulterende program aan sy spesifikasie voldoen. Vir enige substansiële program, verteenwoordig dit ‘n aansienlike hoeveelheid werk. Verskeie navorsinspoging is gerig op die daarstelling van meganiese ondersteuning vir die gebruik van formele metodes tydens ontwikkeling van sagteware. E. W. Dijkstra se calculus van swakste voorkondisie (“weakest precondition”) predikaattransformators [39,38] is een van die eerste pogings om vereistes vir programkorrektheid op ‘n formele en konstruktiewe wyse tydens programontwikkeling te gebruik.

Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: In computer Go, moves are typically selected with the aid of a tree search algorithm. Monte-Carlo tree search (MCTS) is currently the dominant algorithm in computer Go. It has been shown that the inclusion of domain knowledge in MCTS is able to vastly improve the strength of MCTS engines. A successful approach to representing domain knowledge in computer Go is the use of appropriately weighted tactical features and pattern features, which are comprised of a number of hand-crafted heuristics and a collection of patterns respectively. However, tactical features are hand-crafted specifically for Go, and pattern features are Go-specific, making it unclear how they can be easily transferred to other domains. As such, this work proposes a new approach to representing domain knowledge, decision tree features. These features evaluate a state-action pair by descending a decision tree, with queries recursively partitioning the state-action pair input space, and returning a weight corresponding to the partition element represented by the resultant leaf node. In this work, decision tree features are applied to computer Go, in order to determine their feasibility in comparison to state-of-the-art use of tactical and pattern features. In this application of decision tree features, each query in the decision tree descent path refines information about the board position surrounding a candidate move. The results of this work showed that a feature instance with decision tree features is a feasible alternative to the state-of-the-art use of tactical and pattern features in computer Go, in terms of move prediction and playing strength, even though computer Go is a relatively well-developed research area. A move prediction rate of 35.9% was achieved with tactical and decision tree features, and they showed comparable performance to the state of the art when integrated into an MCTS engine with progressive widening. We conclude that the decision tree feature approach shows potential as a method for automatically extracting domain knowledge in new domains. These features can be used to evaluate state-action pairs for guiding searchbased techniques, such as MCTS, or for action-prediction tasks. / AFRIKAANSE OPSOMMING: In rekenaar Go, word skuiwe gewoonlik geselekteer met behulp van ’n boomsoektogalgoritme. Monte-Carlo boomsoektog (MCTS) is tans die dominante algoritme in rekenaar Go. Dit is bekend dat die insluiting van gebiedskennis in MCTS in staat is om die krag van MCTS enjins aansienlik te verbeter. ’n Suksesvolle benadering tot die voorstelling van gebiedskennis in rekenaar Go is taktiek- en patroonkenmerke met geskikte gewigte. Hierdie behels ’n aantal handgemaakte heuristieke en ’n versameling van patrone onderskeidelik. Omdat taktiekkenmerke spesifiek vir Go met die hand gemaak is, en dat patroonkenmerke Go-spesifiek is, is dit nie duidelik hoe hulle maklik oorgedra kan word na ander velde toe nie. Hierdie werk stel dus ’n nuwe verteenwoordiging van gebiedskennis voor, naamlik besluitboomkenmerke. Hierdie kenmerke evalueer ’n toestand-aksie paar deur rekursief die toevoerruimte van toestand-aksie pare te verdeel deur middel van die keuses in die besluitboom, en dan die gewig terug te keer wat ooreenstem met die verdelingselement wat die ooreenstemmende blaarnodus verteenwoordig. In hierdie werk, is besluitboomkenmerke geëvalueer op rekenaar Go, om hul lewensvatbaarheid in vergelyking met veldleidende gebruik van taktiek- en patroonkenmerke te bepaal. In hierdie toepassing van besluitboomkenmerke, verfyn elke navraag in die pad na onder van die besluitboom inligting oor die posisie rondom ’n kandidaatskuif. Die resultate van hierdie werk het getoon dat ’n kenmerkentiteit met besluitboomkenmerke ’n haalbare alternatief is vir die veldleidende gebruik van taktiek- en patroonkenmerke in rekenaar Go in terme van skuifvoorspelling as ook speelkrag, ondanks die feit dat rekenaar Go ’n relatief goedontwikkelde navorsingsgebied is. ’n Skuifvoorspellingskoers van 35.9% is behaal met taktiek- en besluitboomkenmerke, en hulle het vergelykbaar met veldleidende tegnieke presteer wanneer hulle in ’n MCTS enjin met progressiewe uitbreiding geïntegreer is. Ons lei af dat ons voorgestelde besluitboomkenmerke potensiaal toon as ’n metode vir die outomaties onttrek van gebiedskennis in nuwe velde. Hierdie eienskappe kan gebruik word om toestand-aksie pare te evalueer vir die leiding van soektog-gebaseerde tegnieke, soos MCTS, of vir aksie-voorspelling.