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The two envelope problem: an informed choiceTyler, Jeffrey Brian 03 1900 (has links)
The host of a game presents two indistinguishable envelopes to an agent. One of the envelopes is randomly selected and allocated to the agent. The agent is informed that the monetary content of one of the envelopes is twice that of the other. The dilemma is under which conditions it would be beneficial to switch the allocated envelope for the complementary one. The objective of his or her envelope-switching strategy is to determine the benefit of switch- ing the allocated envelope and its content for the expected content of the complementary envelope.
The agent, upon revealing the content of the allocated envelope, must consider the events that are likely to have taken place as a result of the host’s activ- ities. The preceding approach is in stark contrast to considering the agent’s reasoning for a particular outcome that seeks to derive a strategy based on the relative contents of the presented envelopes. However, it is the former reasoning that seeks to identify what the initial amounts could have been, as a result of the observed amount, that facilitates the identification of an appropriate switching strategy.
Knowledge of the content and allocation process is essential for the agent to derive a successful switching strategy, as is the distribution function from which the host sampled the initial amount that is assigned to the first enve- lope.
For every play of the game, once the agent is afforded the opportunity of sighting the content of the randomly allocated envelope, he or she can determine the expected benefit of switching. / Research / M. Sc. (Operations Research)
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Feminist Statements in Fashion Marketing : and Their Affect on Brand ImageWard Gustavsson, Julia, Wollbeck, Maximilian January 2016 (has links)
Sweden is moving towards a society where not being a feminist is considered unmodern and conservative. People are fighting for women's rights and equality between the sexes. This feminist movement in Sweden is starting to show in more and more businesses. The fashion business has recently adapted the same movement and feminism has been used in different types of marketing, such as gender neutral merchandising or statement advertisements. The focus of this thesis is statements on products and the purpose is to investigate how Swedish consumers’ brand image of a high end fashion brand is affected by the brand using symbols of feminist statements on their products. The theoretical framework has been separated into three categories; Brand Image, Consumer Behaviour and Politics in Fashion, which sums up in a conceptual model. The model is tested in the empirical findings that were discovered through two focus groups. Consumers critical minds and high awareness of companies advertising techniques results in the conclusion that consumers demand more political effort in order to trust and accept the statement, apparently an important factor when it comes to change of brand image.
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Automatic Deobfuscation and Reverse Engineering of Obfuscated CodeYadegari, Babak January 2016 (has links)
Automatic malware analysis is an essential part of today's computer security practices. Nearly one million malware samples were delivered to the analysts on a daily basis on year 2014 alone while the number of samples submitted for analysis increases almost exponentially each year. Given the size of the threat we are facing today and the amount of malicious codes emerging every day, the ability to automatically analyze unknown and unwanted software is critically important more than ever. On the other hand, malware writers adapt their malicious codes to new security measurements to protect them from being exposed and detected. This is usually achieved by employing obfuscation techniques that complicate the reverse engineering and analysis of the code by adding lots of unnecessary and irrelevant computations. Most of the malicious samples found in the wild are obfuscated and equipped with complicated anti-analysis defenses intended to hide the malicious intent of the malware by defeating the analysis and/or increasing the analysis time. Deobfuscation (reversing the obfuscation) requires automatic techniques to extract the original logic embedded in the obfuscated code for further analysis. Presumably the deobfuscated code requires less analysis time and is easier to analyze compared to the obfuscated one. Previous approaches in this regard target specific types of obfuscations by making strong assumptions about the underlying protection scheme leaving opportunities for the adversaries to attack. This work addresses this limitation by proposing new program analysis techniques that are effective against code obfuscations while being generic by minimizing the assumptions about the underlying code. We found that standard program analysis techniques, including well-known data and control flow analyses and/or symbolic execution, suffer from imprecision due to the obfuscation and show how to mitigate this loss of precision. Using more precise program analysis techniques, we propose a deobfuscation technique that is successful in reversing the complex obfuscation techniques such as virtualization-obfuscation and/or Return-Oriented Programming (ROP).
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Key profile optimisation for the computational modelling of tonal centreVermeulen, Hendrik Johannes 12 1900 (has links)
Thesis (MPhil)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Tonality cognition incorporates a number of diverse and multidisciplinary aspects, including music
cognition, acoustics, culture, computer-aided modelling, music theory and brain science. Current
research shows growing emphasis on the use of computational models implemented on digital
computers for music analysis, particularly with reference to the analysis of statistical properties,
form and tonal properties. The applications of these analytical techniques are numerous, including
the classification of genre and style, Music Information Retrieval (MIR), data mining and
algorithmic composition.
The research described in this document focuses on three aspects of tonality analysis, namely music
cognition, computational modelling and music theory, particularly from the perspectives of
statistical analysis and key-finding. Mathematical formulations are presented for a number of
computational algorithms for analysing the statistical and tonal properties of music encoded in
symbolic format. These include algorithms for determining the distributions of note durations,
pitch intervals and pitch classes for statistical analysis and for template-based key-finding for tonal
analysis. The implementation and validation of these computational algorithms on the Matlab
software platform are subsequently discussed.
The software application is used to determine whether a more optimal combination of pitch class
weighing model and key profile template for the template-based key-finding algorithm can be
derived, using the 24 preludes from Bach’s Well-tempered Clavier Book I, the Courante from
Bach's Cello Suite in C major and the Gavotte from Bach's French Suite No. 5 in G major (BWV
816) as test material. Four pitch class weighing models, namely histogram weighing, flat weighing,
linear durational weighing and durational accent weighing, are investigated. Two prominent key
profile templates proposed in literature are considered, namely a key profile derived from tonality
cognition experiments and a key profile based on classical music theory principles. The results
show that the key-finding performances of all the combinations of the pitch class weighing models
and existing key profile templates depend on the nature of the test material and that none of the
combinations perform optimally for all test material.
The software application is subsequently used to determine whether a more optimal key profile
template can be derived using a pattern search parameter estimation algorithm. This investigation
was conducted for diverse sets of search conditions, including unconstrained and constrained key
profile coefficients, different pitch class weighing models, various key resolutions and different
search algorithm parameters. Using the same sample material as for the key-finding evaluations,
the investigation showed that a more optimal key profile, compared to existing profiles, can be
derived. In comparing the average key-finding scores for all of the test material, the optimised
profiles outperform the existing profiles substantially. The optimised key profiles introduce new
pitch class hierarchies where the supertonic and the subdominant rate higher at the expense of the
mediant in the major profile to improve the tracking of key modulations. / AFRIKAANSE OPSOMMING: Kognitiewe tonaliteit behels 'n aantal uiteenlopende en multidissiplinêre aspekte, insluitende
musiek, akoestiek, kultuur, rekenaargesteunde modelering, musiekteorie en breinwetenskap.
Huidige navorsing toon toenemende klem op die gebruik van berekenende modelering wat op
digitale rekenaars geimplimenteer is vir musiekanalise, veral met verwysing na die analise van
statistiese eienskappe, vorm en tonale eienskappe. Die aanwending van hierdie analitiese tegnieke
is veelvoudig, insluitende die klassifikasie van genre of styl, onttrekking van musiekinformasie,
dataversameling en algoritmiese komposisie.
Die navorsing wat in hierdie dokument beskryf word fokus op drie aspekte van tonaliteit analise,
naamlik musiekkognisie, berekenende modelering en musiekteorie, veral vanuit die perspektiewe
van statistiese analise and toonsoortsoek. Wiskundige formulerings word aangebied vir 'n aantal
berekeningalgoritmes vir die analise van die statistiese en tonale eienskappe van musiek wat in
simboliese formaat ge-enkodeer is. Hierdie sluit algoritmes in vir die bepaling van die
verspreidings van nootlengtes, toonintervalle en toonklasse vir statistiese analise en vir templaatgebaseerde
toonsoortsoek vir tonale analise. Die implementering en validering van hierdie
berekeningalgoritmes op die Matlab programmatuur platvorm word vervolgens bespreek.
Die programmatuur toepassing word vervolgens gebruik om te bepaal of 'n meer optimale
kombinasie van toonklas weegmodel en toonsoortprofiel templaat vir die templaat-gebaseerde
toonsoortsoek algoritme afgelei kan word, deur gebruik te maak van Bach se Well-tempered Clavier
Book I, die Courante van Bach se Cello Suite in C major en die Gavotte van Bach se French Suite
No. 5 in G major (BWV 816) as toetsmateriaal. Vier toonklas weegmodelle, naamlik histogram
weging, plat weging, lineêre duurtyd weging en duurtyd aksent weging, word ondersoek. Twee
prominente toonsoortprofiel template uit die literatuur word oorweeg, naamlik 'n toonsoortprofiel
wat van tonaliteit kognisie eksperimente afgelei is en 'n toonsoortprofiel gebaseer op klassieke
musiekteoretiese beginsels. Die resultate wys dat die toonsoortsoek prestasies van al die
kombinasies van die toonklas weegmodelle en bestaande toonsoortprofiel template afhang van die
aard van die toetsmateriaal en dat geen van die kombinasies optimaal presteer vir alle toetsmateriaal
nie.
Die programmatuur toepassing word vervolgens aangewend om vas te stel of 'n meer optimale
toonsoortprofiel afgelei kan word deur gebruik te maak van 'n patroonsoek parameterestimasie
algoritme. Hierdie ondersoek is uitgevoer vir uiteenlopende stelle soektoestande, insluitende
onbeperkte en beperkte toonsoortprofiel koëffisiënte, verskillende toonklas weegmodelle, 'n
verskeidenheid toonsoort resolusies en verskillende soekalgoritme parameters. Deur gebruik te
maak van dieselfde toetsmateriaal as vir die toonsoortsoek evaluerings, toon die ondersoek dat 'n
meer optimale toonsoortprofiel, in vergelyking met bestaande profiele, afgegelei kan word. In 'n
vergelyking van die gemiddelde toonsoortsoek prestasie vir al die toetsmateriaal, presteer die geoptimeerde
profiele aansienlik beter as die bestaande profiele. The ge-optimeerde toonsoortprofiele
lei tot nuwe toonklas hiërargiee waar die supertonikum en die subdominant hoër rangposissies
beklee ten koste van die mediant in die majeur profiel, ten einde die navolg van toonsoort
modulasies te verbeter.
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Symbolic control analysis of cellular systemsAkhurst, Timothy John 03 1900 (has links)
Thesis (PhD (Biochemistry))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Metabolic Control Analysis (MCA) provides a powerful quantitative framework for understanding
and explaining the control and regulation within a cellular system. MCA
allows the global control of a steady-state system to be quantified in terms of control
coeficients, which we can express in terms of the local properties referred to as elasticity
coeficients. MCA relates elasticities to control coeficients through a matrix inversion,
thus allowing scientists to predict and quantify how the kinetics of the individual enzymes
affect the systemic behaviour of cellular systems. Traditionally we solved this
problem numerically, while we used algebraic and symbolic control analysis techniques
less frequently. By using symbolic algebraic computation we present a general implementation
of the symbolic matrix inversion of MCA, known as SymCA, which requires
only the description of any allosteric modifier interactions and the stoichiometry of a
cellular system. The algebraic expressions generated allow an in-depth analysis of the
distribution of the control within a system and also of the parameters which exhibit
the greatest effect on this control distribution. This also applies when the exact values
for the elasticities or control coeficients are unknown. We have demonstrated that by
quantifying the control patterns, referred to as `routes of regulation', inherent in all control
coeficient expressions, we can gain insight into how perturbations are propagated
through a cellular system and which regulatory pathways are favoured under changing
conditions. / AFRIKAANSE OPSOMMING: Metaboliese Kontrole-Analise (MKA) bied 'n kragtige kwantitatiewe raamwerk om die
beheer en regulering binne sellulere sisteme te verstaan en te verduidelik. 'n Sleutelaspek
van MKA is dat die globale beheer van 'n sisteem met 'n bestendige toestand gekwantifiseer kan word in terme van kontrole-koefisente en dat hierdie koefisente uitgedruk
kan word in terme van die sisteem se lokale eienskappe, genaamd elastisiteitskoefisente.
Deur van matriksinversie gebruik te maak kan MKA die verband tussen elastisiteitskoefisente en kontrole-koefisente aflei wat mens in staat stel om te sien hoe die kinetika
van die individuele ensiemreaksies die sisteemgedrag op sellulere vlak beinvloed. Die
probleem word tradisioneel hoofsaaklik op numeriese wyse bereken terwyl die gebruik
van algebraiese en simboliese kontrole-analise minder gereeld gebruik word. In hierdie
proefskrif verskaf ons, deur van simboliese algebraiese metodes gebruik te maak, 'n generiese
implementasie van die simboliese matriksinversie van MKA, genaamd SymCA, wat
slegs 'n beskrywing van 'n sellulere sisteem se allosetriese interaksies en die stoichiometrie
benodig. Die algebraiese uitdrukkings sodanig gegenereer stel mens in staat om
'n in-diepte analise te doen om vas te stel waar die beheer binne 'n sisteem le, asook
watter parameters die grootste effek op die kontrole-verspreiding het. Dit geld selfs in
die geval waar die presiese waardes van die elastisiteitskoefisente of kontrole-koefisente
onbekend is. Hierdie proefskrif demonstreer hoe die kwantifisering van kontrole-patrone,
ook gesien as 'roetes van regulering', wat inherent is aan kontrole-koefisent vergelykings,
mens in staat stel om te sien hoe perturbasies in 'n sellulere sisteem voortplant en
watter regulatoriese paaie bevoordeel word onder veranderde kondisies.
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Experiential learning in professional Rugby UnionLloyd, Sam January 2013 (has links)
The aim of this thesis was to understand the role played by experiential learning in professional Rugby Union. Furthermore, to understand how performance information is utilised by coaches and athletes in every day practice. The thesis employed an ethnographic research method, utilising extensive participant observation, interviews, and document analysis. The thesis draws significantly on the theoretical tools of Scho??n, Bourdieu and Foucault. The key results and findings were that coaches used performance related information as a technology of self , and inculcated a hegemonic ideology. Furthermore, power relations were found and manifested inside the coach / athlete relation that reinforced the coaches spatial and temporal dominance. These dominant power relations were legitimised through the omnipresent ideology, and thus reproduced by the players and coaches. While evidence of experiential learning was documented, particularly with the academy players, the social location of practice marginalised the value of experiential learning in the coaching process. This was because performance information and the use of video based reflection were consistently used as tools of coaching authority, discipline and symbolic violence.
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Fuzzy optimisation based symbolic grounding for service robotsLiu, Beisheng January 2013 (has links)
Symbolic grounding is a bridge between task level planning and actual robot sensing and actuation. Uncertainties raised by unstructured environments make a bottleneck for integrating traditional artificial intelligence with service robotics. In this research, a fuzzy optimisation based symbolic grounding approach is presented. This approach can handle uncertainties and helps service robots to determine the most comfortable base region for grasping objects in a fetch and carry task. Novel techniques are applied to establish fuzzy objective function, to model fuzzy constraints and to perform fuzzy optimisation. The approach does not have the short comings of others’ work and the computation time is dramatically reduced in compare with other methods. The advantages of the proposed fuzzy optimisation based approach are evidenced by experiments that were undertaken in Care-O-bot 3 (COB 3) and Robot Operating System (ROS) platforms.
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Automated coverage calculation and test case generationMorrison, George Campbell 03 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: This research combines symbolic execution, a formal method of static analysis, with various
test adequacy criteria, to explore the e ectiveness of using symbolic execution for calculating
code coverage on a program's existing JUnit test suites. Code coverage is measured with a
number of test adequacy criteria, including statement coverage, branch coverage, condition
coverage, method coverage, class coverage, and loop coverage. The results of the code coverage
calculation is then used to automatically generate JUnit test cases for areas of a program that
are not su ciently covered. The level of redundancy of each test case is also calculated during
coverage calculation, thereby identifying fully redundant, and partially redundant, test cases.
The combination of symbolic execution and code coverage calculation is extended to perform
coverage calculation during a manual execution of a program, allowing testers to measure the
e ectiveness of manual testing.
This is implemented as an Eclipse plug-in, named ATCO, which attempts to take advantage
of the Eclipse workspace and extensible user interface environment to improve usability of the
tool by minimizing the user interaction required to use the tool.
The code coverage calculation process uses constraint solving to determine method parameter
values to reach speci c areas in the program. Constraint solving is an expensive
computation, so the tool was parallellised using Java's Concurrency package, to reduce the
overall execution time of the tool. / AFRIKAANSE OPSOMMING: Hierdie navorsing kombineer simboliese uitvoering, 'n formele metode van statiese analise, met
verskeie toets genoegsaamheid kriteria, om die e ektiwiteit van die gebruik van simboliese
uitvoer te ondersoek vir die berekening van kode dekking op 'n program se bestaande JUnit
toets stelle. Kode dekking word gemeet deur verskeie toets genoegsaamheid kriteria, insluited
stelling dekking, tak dekking, kondisie dekking, metode dekking, klas dekking, en lus dekking.
Die resultate van die kode dekking berekeninge word dan gebruik om outomaties JUnit toets
voorbeelde te genereer vir areas van 'n program wat nie doeltre end ondersoek word nie. Die
vlak van oortolligheid van elke toets voorbeeld word ook bereken gedurende die dekkingsberekening,
en daardeur word volledig oortollige, en gedeeltelik oortollige, toets voorbeelde
identi seer. Die kombinasie van simboliese uitvoer en kode dekking berekening is uitgebrei
deur die uitvoer van dekking berekeninge van 'n gebruiker-beheerde uitvoer, om sodoende kode
dekking van 'n gebruiker-beheerde uitvoer van 'n program te meet. Dit laat toetsers toe om
die e ektiwiteit van hulle beheerde uitvoer te meet.
Bogenoemde word ge mplimenteer as 'n Eclipse aanvoegsel, genaamd ATCO, wat poog om
voordeel te trek vanuit die Eclipse werkspasie, en die uitbreibare gebruiker oordrag omgewing,
om die bruikbaarheid van ATCO te verbeter, deur die vermindering van die gebruiker interaksie
wat benodig word om ATCO te gebruik.
Die kode dekking berekeningsproses gebruik beperking oplossing om metode invoer waardes
te bereken, om spesi eke areas in die program te bereik. Beperking oplossing is 'n duur berekening,
so ATCO is geparalleliseer, met behulp van Java se Concurrency pakket, om die algehele
uitvoer tyd van die program te verminder.
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Space and society at Bam : an archaeological investigation of Iranian urban spaceKarimian, Hassan January 2003 (has links)
During the 1980s, it was frequently claimed that spatial patterns of archaeological and contemporary settlements were closely related to the social nature of the societies which had created and modelled them (Hietala 1984; Hillier & Hanson 1984). Despite a decade of alternative claims, such theories are still widely accepted although in many cases the emphasis has shifted from economic factors to symbolic or social ones. The presence of a class-based social system is one of the major characteristics of Iranian society during the Sasanian era (224-651 CE). This social system was based upon the official religion of Sasanians - Zoroastrianism - and had a major impact on most aspects of Iranian society during this period. The far-reaching impact of this social system on architectural space and urban infrastructure is clearly representative of a class-based society. The collapse of the Sasanian world, accelerated by Arab invasions (641 CE), severely reduced the dominance of Zoroastrianism within Iran, heralding a fundamental change in the social life of its people. These changes, accompanied by the acceptance of a new religion, have been the focus of several researchers over the last decades (Kennedy 2001). In contrast to Sasanian society, Early Islamic social structure was characterised as one of equality and its urban forms as ones with little differentiation as typified by Medina (Zarrinkub 1993). The aim of this dissertation is to test the above assumptions and models with reference to a single urban site - the city of Barn. Selected due to its Pre-Islamic and Islamic occupations, its excellent state of preservation allows a full testing of the above assumptions through archaeological analysis. The results of this research indicate a continuation of patterns of Sasanian space and society into the Islamic period. In addition, the space and society of Bam, documented in this research, provides an important step towards a further understanding of the social and spatial organisation of Sasanian and Early-Islamic cities, as well as providing a foundation for additional research in this field.
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Quelques applications de l'algébre différentielle et aux différences pour le télescopage créatifChen, Shaoshi 16 February 2011 (has links) (PDF)
Depuis les années 90, la méthode de création télescopique de Zeilberger a joué un rôle important dans la preuve automatique d'identités mettant en jeu des fonctions spéciales. L'objectif de long terme que nous attaquons dans ce travail est l'obtension d'algorithmes et d'implantations rapides pour l'intégration et la sommation définies dans le cadre de cette création télescopique. Nos contributions incluent de nouveaux algorithmes pratiques et des critères théoriques pour tester la terminaison d'algorithmes existants. Sur le plan pratique, nous nous focalisons sur la construction de télescopeurs minimaux pour les fonctions rationnelles en deux variables, laquelle a de nombreuses applications en lien avec les fonctions algébriques et les diagonales de séries génératrices rationnelles. En considérant cette classe d'entrées contraintes, nous parvenons à mâtiner la méthode générale de création télescopique avec réduction bien connue d'Hermite, issue de l'intégration symbolique. En outre, nous avons obtenu pour cette sous-classe quelques améliorations des algorithmes classiques d'Almkvist et Zeilberger. Nos résultats expérimentaux ont montré que les algorithmes à base de réduction d'Hermite battent tous les autres algorithmes connus, à la fois en ce qui concerne la complexité au pire et en ce qui concerne les mesures de temps sur nos implantations. Sur le plan théorique, notre premier résultat est motivé par la conjecture de Wilf et Zeilberger au sujet des fonctions hyperexponentielles-hypergéométriques holonomes. Nous présentons un théorème de structure pour les fonctions hyperexponentielles-hypergéométriques de plusieurs variables, indiquant qu'une telle fonction peut s'écrire comme le produit de fonctions usuelles. Ce théorème étend à la fois le théorème d'Ore et Sato pour les termes hypergéométriques en plusieurs variables et le résultat récent par Feng, Singer et Wu. Notre second résultat est relié au problème de l'existence de télescopeurs. Dans le cas discret à deux variables, Abramov a obtenu un critère qui indique quand un terme hypergéométrique a un télescopeur. Des résultats similaires ont été obtenus pour le $q$-décalage par Chen, Hou et Mu. Ces résultats sont fondamentaux pour la terminaison des algorithmes s'inspirant de celui de Zeilberger. Dans les autres cas mixtes continus/discrets, nous avons obtenu deux critères pour l'existence de télescopeurs pour des fonctions hyperexponentielles-hypergéométriques en deux variables. Nos critères s'appuient sur une représentation standard des fonctions hyperexponentielles-hypergéométriques en deux variables, sur sur deux décompositions additives.
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