This dissertation presents an analysis of the angle modulated particle swarm optimisation (AMPSO) algorithm. AMPSO is a technique that enables one to solve binary optimisation problems with particle swarm optimisation (PSO), without any modifications to the PSO algorithm. While AMPSO has been successfully applied to a range of optimisation problems, there is little to no understanding of how and why the algorithm might fail. The work presented here includes in-depth theoretical and emprical analyses of the AMPSO algorithm in an attempt to understand it better. Where problems are identified, they are supported by theoretical and/or empirical evidence. Furthermore, suggestions are made as to how the identified issues could be overcome. In particular, the generating function is identified as the main cause for concern. The generating function in AMPSO is responsible for generating binary solutions. However, it is shown that the increasing frequency of the generating function hinders the algorithm’s ability to effectively exploit the search space. The problem is addressed by introducing methods to construct different generating functions, and to quantify the quality of arbitrary generating functions. In addition to this, a number of other problems are identified and addressed in various ways. The work concludes with an empirical analysis that aims to identify which of the various suggestions made throughout this dissertatioin hold substantial promise for further research. / Dissertation (MSc)--University of Pretoria, 2017. / Computer Science / MSc / Unrestricted

MSCAGR / Department of Agricultural Economics and Agribusiness / The study was conducted in the Mutale Local Municipality, Vhembe District of South Africa on a proportionally randomly selected sample of 153 smallholder farmers after clustering them into agricultural zones and commodity groupings (vegetables under irrigation, dryland maize and citrus fruit farming). Data were collected through a structured qualitative and quantitative questionnaire that was administered face-to-face to respondents and captured into the SPSS Version 24 computer program. The same program was used to analyse data through cross tabulations and logistic regression modelling. In particular, the study focussed on the impact of socio-economic characteristics, challenges that farmers face and views of extension officers on transforming subsistence farmers towards commercialization. The most critical findings of the study were dominance of women, lower youth participation, poor training and educational achievements, non-membership to agricultural organizations, low income levels and dependence on social grants and lack of credit as factors that could impact on farmers’ transformation process. Farmers’ challenges that could impact on transformation were identified as lack of production inputs, water, access to market and supportive infrastructure such as mechanization. However, the views of extension officers regarding transformation centred mostly around insufficient land holdings, climate change and financial support. In contrast to farmers, extension officers viewed market access as a minor challenge. The study recommended for development of strategies that could increase youth participation in farming such as start-up credit, reduction of dependence on social grants by adopting strategies that could increase productivity and thus income, exposure to funding opportunities through training and increased involvement of institutions of higher learning into smallholder farming activities.

Depuis le début du XXème siècle et les avancées théoriques de Freud sur l’inconscient, les sociétés occidentales ont progressivement évolué vers une dépathologisation des sexualités et des sexuations. A tel point que l’année 2014 a vu l’officialisation d’une identité de sex non-specific sur le territoire australien. Cette thèse en psychopathologie et psychanalyse se propose d’interroger la rencontre entre singularités subjectives et déterminants sociétaux afin d’en hypothéquer les possibles résonnances qui ont permis l’avènement de la première citoyenneté adulte de sexuation non-specific. Quelles conséquences la reconnaissance des nouvelles identités non binaires peut-elle engendrer sur la modélisation de l’appareil psychique et quels aménagements théoriques peut-on envisager pour la théorisation psychanalytique du XXIème siècle ? / Since the beginning of the 20th century and Freud's theoretical progresses on the unconscious, Western societies have gradually evolved towards a depathologization of sexualities and sexuations. To such an extent that the year 2014 saw the officialization of a non-specific sex identity on the Australian territory. This thesis in psychopathology and psychoanalysis proposes to question the meeting between subjective singularities and societal determiners in order to hypothecate the possible echoes that led to the emergence of the first adult citizenship with non-specific sex. What consequences can the recognition of new non-binary identities generate on the modeling of the psychic apparatus and what theoretical adjustments can be considered for the psychoanalytic theorization of the 21st century?

In this work, ordered all-binary short-period strained InAs/GaAs superlattice quantum wells were studied as an alternative to strained ternary alloy InGaAs/GaAs quantum wells. InGaAs quantum wells QWs have been of great interest in recent years due to the great potential applications of these materials in future generations of electronic and optoelectronic devices. The all binary structures are expected to have all the advantages of their ternary counterparts, plus several additional benefits related to growth, to the elimination of alloy disorder scattering and to the presence of a higher average indium content.

Digital data has many benefits, but what happens if it’s in error? Moreover, how can we tell if a bit has been flipped? Our discussion begins with parity.

Two applications of a binary tree data type based on a simple pairing function (a bijection between natural numbers and pairs of natural numbers) are explored. First, the tree is used to encode natural numbers, and algorithms that perform basic arithmetic computations are presented along with formal proofs of their correctness. Second, using this "canonical" representation as a base type, algorithms for encoding and decoding additional isomorphic data types of other mathematical constructs (sets, sequences, etc.) are also developed. An experimental application to a memory management system is constructed and explored using these isomorphic types. A practical analysis of this system's runtime complexity and space savings are provided, along with a proof of concept framework for both applications of the binary tree type, in the Java programming language.

Gene evolution is important in several areas, not least the understanding of thehuman body. Since the time of Darwin, researchers have visualized evolution withrooted binary trees. Hence, genes evolve constrained to how species have evolvedand that relationship is interesting to understand and explore. To solve this, onemethod is to infer the gene tree into the species tree, a so called reconciliation, butvisualizing reconciled trees with classical binary trees often results in clutteredvisualizations that quickly become difficult to understand. Therefore, in this thesisI present a new visualization method, Genvo, for reconciled phylogenies, and definea simple tree layout algorithm. I also present a problem characterization for thedomain-specific tasks, performed when working with gene evolution visualizations.A prototype of Genvo is then studied in a small pair analytics study, where fivepairs of master students tested the developed a prototype of Genvo. The results areanalyzed compared to a workshop with three participants, all with prior knowledgein the field of gene evolution. The analysis indicates a faster understanding of thegene data in Genvo, most likely through the pre-attentive features. / Att förstå geners evolution är relevant för flertalet områden, inte minst för attutforska den mänskliga kroppen. Ända sedan Darwin har forskare visualiseratevolution med hjälp av rotade binära träd. Dock utvecklas gener begränsat till hurdess arter utvecklats, och denna relation är av intresse att förstå och utforska. Attgöra en sammanslagning av ett gen-träd med sitt art-träd (reconciliation) är ett sättatt visualisera relationen, men lösningen blir ofta väldigt rörig och svårförståelig.Därför presenterar jag i detta examensarbete Genvo, ett reconciliation programsom använder en simpel träd-layout-algoritm för att visualisera geners evolution irelation till arters evolution i 3D. Jag presenterar även en gedigen problemkarakteriseringför de uppgifter forskarna utför när de jobbar med dagensvisualiseringsverktyg. En prototyp av Genvo testades sedan i en pairanalytics studie, med en testgrupp bestående av fem par. Studien är sedan jämfördmed en workshop där tre testpersoner, med tidigare erfarenhet, jobbade medsamma uppgifter. Analysen av studiernas resultat tyder på en snabbare förståelseav datan när användarna använde sig av Genvo.

Transgender individuals experience daily discrimination, harrasment and are overrepresented in statistics such as poor mental health and suicide rates. This study aims to analyse how transgender individuals write about their identity and identityconstruction in relation to their enviroment. It also set out to find patterns in the experiences of transgender people to analyse them using Erving Goffmans dramaturgy and Judith Butlers concept of gender as performative. To achieve this narrative content analysis was used to analyse fifteen short biographical stories written by transgendered individuals about themselves. The purpose of this was to recognize patterns in the experiences and interactions they choose to put forth when talking about themselves. In creating a better understanding of transgender identity this study hopes to be a path in bettering the care and treatment of transgender people who seek aid from socialworkers. The results brought forward 4 main themes which were titled “defining yourself”, “Questioning of the identity”, “solidarity and support in one's identity” and “identity as a standard breaker”. Defining yourself means that the transgendered individuals saw identity as what you consider yourself to be and that the common experience was that the environments expectations did not match with their gender identity. The results were very unanimous except that the binary transpeople and nonbinary transpeople wrote a differently of how they felt other people reacted to their identity. The theme of questioning of the identity consideres the direct diskrimination, harrasment and questioning the transgender indivudals wrote about wich where reocurring in multiple peoples experiences. These experiences included being expected to conform to norms, being misgendered or insulted and difficulties in getting gender affirming care and diagnosis for gender dysphoria. Solidarity and support in one's identity refers to a recurring theme of people writing about how they felt solidarity and acceptance in groups which did not question their identity. Many wrote that they only felt accepted in exclusively transgender groups. Another aspect of this was that many attributed good health, acceptance of self and courage to come out, to the availability of information about being transgender and transgender support groups. The last theme was less unanimous with a minority expressing feelings of pride and solidarity with them being a standard breaker or deviant. Few even considered it a big part of their identity.

Indiana University-Purdue University Indianapolis (IUPUI) / Dynamic Binary Instrumentation (DBI) is one way to monitor a distributed system in real-time without modifying source code. Previous work has shown it is possible to instrument distributed systems using standards-based distributed middleware. Existing work, however, only applies to a single middleware, such as CORBA. This thesis therefore presents a tool named the Standards-based Distributed Middleware Monitor (SDMM), which generalizes two modern standards-based distributed middleware, the Data Distribution Service (DDS) and gRemote Procedure Call (gRPC). SDMM uses DBI to extract values and other data relevant to monitoring a distributed system in real-time. Using dynamic instrumentation allows SDMM to capture information without a priori knowledge of the distributed system under instrumentation. We applied SDMM to systems created with two DDS vendors, RTI Connext DDS and OpenDDS, as well as gRPC which is a complete remote procedure call framework. Our results show that the data collection process contributes to less than 2% of the run-time overhead in all test cases.

<div><div><div><p>Binary code analysis is widely used in many applications, including reverse engineering, software forensics and security. It is very critical in these applications, since the analysis of binary code does not require source code to be available. For example, in one of the security applications, given a potentially malicious executable file, binary analysis can help building human inspectable representations such as control flow graph and call graph.</p><p>Existing binary analysis can be roughly classified into two categories, that are static analysis, and dynamic analysis. Both types of analysis have their own strengths and limitations. Static binary analysis is based on the result of scanning the binary code without executing it. It usually has good code coverage, but the analysis results are sometimes not quite accurate due to the lack of dynamic execution information. Dynamic binary analysis, on the other hand, is based on executing the binary on a set of inputs. On the contrast, the results are usually accurate but heavily rely on the coverage of the test inputs, which sometimes do not exist.</p><p>In this thesis, we first present a novel systematic binary analysis framework called X-Force. Basically, X-Force can force the binary to execute without using any inputs or proper environment setup. As part of the design of our framework, we have proposed a number of techniques, that includes (1) path exploration module which can drive the program to execute different paths; (2) a crash-free execution model that could detect and recover from execution exceptions properly; (3) overcoming a large number of technical challenges in making the technique work on real world binaries.</p><p>Although X-Force is a highly effective method to penetrate malware self-protection and expose hidden behavior, it is very heavy-weight. The reason is that it requires tracing individual instructions, reasoning about pointer alias relations on-the-fly, and repairing invalid pointers by on-demand memory allocation. To further solve this problem, we develop a light-weight and practical forced execution technique. Without losing analysis precision, it avoids tracking individual instructions and on-demand allocation. Under our scheme, a forced execution is very similar to a native one. It features a novel memory pre-planning phase that pre-allocates a large memory buffer, and then initializes the buffer, and variables in the subject binary, with carefully crafted values in a random fashion before the real execution. The pre-planning is designed in such a way that dereferencing an invalid pointer has a very large chance to fall into the pre-allocated region and hence does not cause any exception, and semantically unrelated invalid pointer dereferences highly likely access disjoint (pre-allocated) memory regions, avoiding state corruptions with probabilistic guarantees.</p></div></div></div>