With today’s focus on Continuous Integration, test cases are used to ensure the software’s reliability when integrating and developing code. Test cases that behave in an undeterministic manner are known as flaky tests, which threatens the software’s reliability. Because of flaky test’s undeterministic nature, they can be troublesome to detect and correct. This is causing companies to spend great amount of resources on flaky tests since they can reduce the quality of their products and services. The aim of this thesis was to develop a usable tool that can automatically detect flakiness in the Randomness category. This was done by initially locating and rerunning flaky tests found in public Git repositories. By scanning the resulting pytest logs from the tests that manifested flaky behaviour, noting indicators of how flakiness manifests in the Randomness category. From these findings we determined tracing to be a viable option of detecting Randomness as a cause of flakiness. The findings were implemented into our proposed tool FlakyReporter, which reruns flaky tests to determine if they pertain to the Randomness category. Our FlakyReporter tool was found to accurately categorise flaky tests into the Randomness category when tested against 25 different flaky tests. This indicates the viability of utilizing tracing as a method of categorizing flakiness.

Laminated carbon fibre-reinforced polymer (CFRP) composites are already well established in structural applications where high specific strength and stiffness are required. Damage in these laminates is usually localised and may involve numerous mechanisms, such as matrix cracking, laminate delamination, fibre debonding or fibre breakage. Microstructures in CFRPs are non-uniform and irregular, resulting in an element of randomness in the localised damage. This may in turn affect the global properties and failure parameters of components made of CFRPs. This raises the question of whether the inherent stochasticity of localised damage is of significance for application of such materials. This PhD project is aimed at developing numerical models to analyze the effect of material randomness on delamination damage in CFRP materials by the implementation of the cohesive-zone model (CZM) within the framework of the finite-element (FE) method. Both the unidirectional and cross-ply laminates subjected to quasi-static loading conditions were studied. The initiation and propagation in delamination of unidirectional CFRP laminates were analyzed. The CZM was used to simulate the progress of that failure mechanism in a pre-cracked double-cantilever beam (DCB) specimen loaded under mode-I employing initially, a two-dimensional FE model. Model validation was then carried out comparing the numerical results with experimental data. The inherent microstructural stochasticity of CFRP laminates was accounted for in the simulations, and various statistical realizations for a half-scatter of 50% of fracture energy were performed, based on the approximation of that parameter with the Weibull s two-parameter probability density function. More detailed analyses were undertaken employing three-dimensional DCB models, and a number of statistical realizations based on variation of fracture energy were presented. In contrast to the results of two-dimensional analyses, simulations with 3D models demonstrated a lower load-bearing capacity for most of the random models as compared to the deterministic model with uniform material properties. The damaged area and the crack lengths in laminates were analyzed, and the results showed higher values of those parameters for random realizations compared to the uniform case for the same levels of applied displacement. The effect of material randomness on delamination in CFRP cross-ply laminates was also investigated. Initially, two-dimensional finite-element analyses were carried out to study the effect of microstructural randomness in a cross-ply laminate under bending with the direct introduction of matrix cracks with varying spacings and delamination zones. A considerable variation in the stiffness for cases with different crack spacings suggested that the assumption of averaged distributions of defects can lead to unreliable predictions of structural response. Three-dimensional uniform, deterministic cross-ply laminate models subjected to a tensile load were analyzed to study the delamination initiation and propagation from the tips of a pre-existing matrix crack. The material s stochasticity was then introduced, and a number of random statistical realizations were analyzed. It was observed that by neglecting the inherent material randomness of CFRP laminates, the initiation conditions for delamination as well as the character of its propagation cannot be properly detected and studied. For instance, the delamination crack length value for all the simulated random statistical realizations predicted its higher magnitudes compared to the uniform (deterministic) case for the same value of applied strain. Furthermore, the location of delamination initiation was shown to be different for different random statistical realizations. Another aspect, emphasizing the importance of microstructural randomness, was the scatter in the magnitudes of global strain at the instance of initiation and subsequent propagation of delamination. In summary, the material randomness in CFRPs can induce randomness in localised damage and it can affect the global properties of laminates and critical failure parameters. These effects can be investigated computationally through the use of stochastic cohesive-zone elements.

Pseudorandom generators belong to the primary focus of cryptology. The key to every cipher has to be generated at random, otherwise the security of the whole cipher is threatened. Another point of importance is the pseudorandom generators' close relationship to the stream ciphers. In this work, we first introduce statistical theory related to randomness testing. Then, we describe 8 classical statistical tests. We introduce a concept of next bit testing and derive variants of previous tests. Moreover, with this new battery of tests we examine the randomness of SHA-3 second round candidates and present the results. Also a sensitivity of tests is investigated and several useful transformations are shown. Powered by TCPDF (www.tcpdf.org)

L’évolution du vivant est un concept majeur pour les sciences biologiques contemporaines, mais également un objet d’enseignement complexe. En France, l'évolution du vivant est introduit dès l’école primaire. Cet enseignement ne devient explicite qu’en fin de la scolarité obligatoire. Cette étude vise à mieux comprendre comment les conceptions de collégiens français sur l’évolution du vivant se modifient tout au long du collège et comment leurs conceptions du hasard peuvent influencer leur acceptation et leur compréhension de ce concept. Pour cela, un questionnaire, UnRESt est élaboré et permet d’étudier les conceptions de plus de 1600 collégiens de l'évolution du vivant et du hasard, et d’établir les relations éventuelles entre ces deux types de conceptions. Il est construit sur la base des résultats obtenus dans des études exploratoires (questionnaire ouvert, discussion à visée philosophique). L’étude révèle que, quel que soit le niveau de classe, la moitié des collégiens interrogés acceptent l’évolution du vivant, et un tiers d’entre eux semblent avoir une compréhension en désaccord avec une pensée évolutionniste. Selon les espèces étudiées, une vision explicative 'transformiste' subsiste chez les élèves. L’étude révèle également que l’acceptation et la compréhension de l’évolution du vivant sont en lien avec les conceptions du hasard. En particulier, les résultats témoignent d’un obstacle dans l’utilisation du mot hasard au sens de contingence, ainsi qu’une influence de leur vision du hasard ‘probabliste’ sur leur compréhension des mécanismes d’évolution. Cette recherche appelle à laisser une place plus importante au hasard dans l’enseignement au collège. / Evolution of living species is a major concept for the contemporary biological sciences, but also a complex object of teaching. In France, the evolution of living species starts in primary school. This teaching becomes well identified only at the end of compulsory schooling. This study aims a better understanding on the change of the conceptions of secondary school students along junior high school and how their conceptions of randomness can influence their acceptation and their understunding of this concept. Consequently, a questionnaire, UnRESt has been elaborated to study the mainstream conceptions of more than 1600 students about the evolution of living and randomness and to find potential links between these two types of conceptions. The UnRESt ingineering is based on exploratory studies (open-ended questions, philosophical discussion). The study shows that a half of the students accept the evolution of living species and a third of them seems to have an understanding in opposition with an evolutionist understanding. According to the species studied, a ‘transformist’ vision is favoured by student. They highlights also that the acceptation and the understanding of the evolution are related to the students’ conceptions of randomness. More specifically, the results show an obstacle in the use of the word randomness with the meaning of contingency and an influence of their vision of ‘probabilist’ randomness on their understanding of the evolution mechanisms. The research concludes on the place to give to the scientific concept of randomness in the teaching in secondary school.

The Wind Projects are based around ideas about materialization. They are an attempt at combining factors related to textiles, such as patterns, structure, materials and body with abstract ideas about movement, change, unpredictability and interrelated relationships between materials, environments objects and actions. / Program: Master in Textile Design

Em nossa prática docente no ensino da Estatística para os cursos de engenharia temos constatado a dificuldade dos alunos no entendimento dos conceitos envolvidos nos métodos estatísticos, tendo como conseqüência a falta de motivação para a sua aprendizagem e, em geral, um elevado índice de reprovação. Passamos, então, a refletir sobre as causas dessa dificuldade e os meios de eliminá-las. Verificamos que o caráter problemático do ensino da Estatística decorre de uma equivocada visão da realidade, conseqüência da pouca familiaridade dos alunos com os fenômenos aleatórios que, embora estejam presentes em seu cotidiano, devido ao caráter excessivamente determinista dos currículos escolares, em geral, não são estudados no ensino fundamental e médio. Os objetivos do presente trabalho consistem em: (1) explicitar uma concepção da realidade em que o equilíbrio determinístico/aleatório seja restaurado; (2) repensar o ensino da Probabilidade e da Estatística nos diversos níveis tendo em vista tal equilíbrio e, a partir dele; (3) propor uma nova organização da disciplina Estatística nos cursos de graduação em Engenharia. Fomos buscar no pensamento filosófico e na evolução das idéias da ciência física a concepção predominante sobre os aspectos determinísticos e aleatórios dos fenômenos naturais, e constatamos que esses aspectos convivem e interagem continuamente e que a aleatoriedade é uma característica intrínseca da natureza. Apresentamos algumas reflexões sobre o conceito de Probabilidade e o conhecimento estatístico, destacando sua importância para se alcançar uma adequada compreensão da realidade e do mundo que nos cerca. Uma formação deficiente no conhecimento probabilístico e estatístico pode conduzir o aluno a uma visão distorcida da realidade. Entendendo que o livro didático utilizado pelo professor é um indicador importante de sua concepção sobre a Estatística e, conseqüentemente, de sua forma de ação docente, fizemos um estudo dos principais livros didáticos utilizados pelos professores de Estatística nos cursos de Engenharia. Constatamos que, salvo algumas poucas exceções, esses livros são baseados em uma concepção predominantemente determinística da realidade. Nessa concepção, priorizam-se o aspecto matemático e a aplicação das técnicas, em relação à construção dos significados dos conceitos necessários ao entendimento da realidade. A verificação desse desequilíbrio entre os aspectos determinísticos e aleatórios no ensino da Estatística nos cursos de Engenharia nos conduziu à proposta de uma nova prática docente, com a qual imaginamos que o desejado equilíbrio seja restaurado. Em sintonia com o fato de que a aleatoriedade é uma característica importante da realidade, propõe-se uma organização do processo de ensino aprendizagem partindo-se de exemplos contextualizados nas áreas de interesse dos alunos, valorizando-se o trabalho em grupos com a utilização de programas estatísticos para computador e permitindo-se a participação ativa do aluno na construção do conhecimento. Para viabilizar a implantação dessa nova prática são necessárias algumas ações relacionadas com a inclusão do estudo dos fenômenos aleatórios na educação básica e com a formação de professores. Acreditamos que com a nova prática docente proposta se conseguirá uma maior compreensão da realidade, promovendo-se o equilíbrio entre as técnicas e os significados dos conceitos, restaurando-se o equilíbrio entre os aspectos determinísticos e aleatórios da realidade, e aumentando no aluno a motivação pela aprendizagem da Estatística. / In our daily teaching experience in Statistics in Engineering curricula we notice the student\'s difficulties to understand the concepts related to the statistics methods that give rise to lack of motivation in learning, and consequently to high rates of failure. We reflected on the causes of these difficulties and on means to surpass them. We observed that the problematic aspect of teaching Statistics is due to a wrong vision of reality, as a consequence of the low familiarity of the students with random phenomena, although their presence in the every day lives of the students, are not studied in colleges and schools because of the excessive deterministic character of the various curricula. The objectives of this work are: (1) to give an explicit conception of reality in which the deterministic/random equilibrium is restored; (2) to reconsider the teaching of Probability and Statistics in all levels keeping in mind that equilibrium, and, after that; (3) suggest a new organization of the discipline Statistics in undergraduate Engineering curriculum. We looked into the philosophical thinking and into the evolution of ideas in the physical sciences about the dominant conception of deterministic and random aspects of the natural phenomena; we then became aware that these aspects interact and continually live side by side and that the randomness is a intrinsic characteristic of nature. We present some reflections about the concept of Probability and the Statistics knowledge, highlighting its importance to achieve an adequate comprehension of reality and the world which surrounds us. A deficient training in probabilistic and statistic knowledge can guide the student to a distorted comprehension of reality. As we think that the textbook adopted in a course indicates how the instructor has his/her own conception about Statistics, and consequently how he/she teaches the subject, we established that, with few exceptions, the textbooks are based on a deterministic conception of reality; they pay more attention to the mathematics and application of techniques than to the building of the necessary concepts to understand it. The observation of this unbalance between deterministic and random aspects in the teaching of the subject in engineering made us propose a new teaching practice to recover it. Being aware that randomness is an important characteristic of reality, we propose an organization in the teaching-learning process starting from examples taken from the student\'s areas of interest, placing a high value on jobs taken in groups with the help of statistics computer software which enables an active participation of the student in the building of knowledge. For doing so it is necessary to take some actions related to the inclusion of the study of random phenomena in basic education and in the training of instructors. We believe that, with this new approach, a better understanding of reality will be achieved, with the equilibrium between techniques and the comprehension of concepts, as well as the equilibrium between deterministic and random aspects of reality, increasing the student motivation to learn Statistics.

For all the successes of the two edifices of modern physics, quantum theory and Einstein's relativity, a fundamental description of the Universe as a whole -- a theory that informs as to the true nature of reality -- has continued to elude science. This thesis describes the development and evolution of a new paradigm called Process Physics, a radical information-theoretic modelling of reality. It is argued that the failure of the extant approaches in physics is the direct consequence of limitations stemming from the mathematization, language and methodology of theoretical physics: the limitations of the postulated background spatial concepts and geometric modelling of time, the limitations of quantum theory in its failure to account for the measurement process and classicality; and the limitations of formal systems. In contrast, Process Physics utilizes the limitations of logic first identified by Godel and asserts the priority of process and relational endophysics, realized via a stochastic, autopoietic bootstrap system whose properties emerge a posteriori rather than being assumed a priori. The work is arranged in two parts. Part I discusses the historical, philosophical, and metaphysical foundations of physics to consider how the prevailing views in modern physics arose and what this revealed and contributed to the development of Process Physics. Part II describes the fundamentals of the new theory and its implementation, and demonstrates the viability of looking outside the current paradigms by showing that Process Physics yields unified emergent phenomena that permit an understanding of fundamental processes and penultimately motivate both quantum theory and relativity as relevant higher-level descriptors within their respective domains.

A micro-world is described, in which many analogies involving strikingly different concepts and levels of subtlety can be made. The question "What differentiates the good ones from the bad ones?" is discussed, and then the problem of how to implement a computational model of the human ability to come up with such analogies (and to have a sense for their quality) is considered. A key part of the proposed system, now under development is its dependence on statistically emergent properties of stochastically interacting "codelets" (small pieces of ready-to-run code created by the system, and selected at random to run with probability proportional to heuristically assigned "urgencies"). Another key element is a network of linked concepts of varying levels of "semanticity", in which activation spreads and indirectly controls the urgencies of new codelets. There is pressure in the system toward maximizing the degree of "semanticity" or "intensionality" of descriptions of structures, but many such pressures, often conflicting, must interact with one another, and compromises must be made. The shifting of (1) perceived oundaries inside structures, (2) descriptive concepts chosen to apply to structures, and (3) features perceived as "salient" or not, is called "slippage". What can slip, and how are emergent consequences of the interaction of (1) the temporary ("cytoplasmic") structures involved in the analogy with (2) the permanent ("Platonic") concepts and links in the conceptual proximity network, or "slippability network". The architecture of this system is postulated as a general architecture suitable for dealing not only with fluid analogies, but also with other types of abstract perception and categorization tasks, such as musical perception, scientific theorizing, Bongard problems and others.

This thesis aims at exploring how probabilistic reasoning arises in explorative learning situations that are random in nature. The focus is especially on what learners with scant experience of formal theories of probability do and can do when dealing with compound random situations in which they are offered opportunities to integrate different probabilistic lines of reasoning. Three studies were carried out for the purpose of gaining an understanding of how learners’ probabilistic reasoning is organised and re-organised in explorative, random-dependent situations. In two of the studies 12 to 13 year-old students acted within a dice-game setting, which was based on the total of two dice. The third study examined 14 to 16 year-old students’ ways of dealing with ICT-versions of compound, independent events viewed in a random-dependent ramified structure. To uncover the basis and the content of the students’ reasoning, behaviour has been regarded in terms of intentions. That is, to understand and make sense of the students’ reasoning, their activities have been matched and re-matched with conjectures about their intents to fulfil certain goals. Although the students were acting on the same learning material, the analyses revealed various kinds of probabilistic reasoning among the students. It has been argued that students’ various ways of dealing with chance encounters may be understood and explained with reference to the ways in which they interpret the learning situations. Thus, this thesis suggests that probabilistic reasoning takes form through a process of contextualisation, i.e. through a compound process where the cognitive activity oscillates between interpretations and reflections about context, the focal event and new information that comes into play. This thesis reveals that students, prior to instruction, are able to devise ideas of an underlying probability distribution in the case of compound random phenomena. The students bring into the discussion geometrical and numerical considerations, as well as arguments reflecting principles of the law of large numbers.

The study looked at how misperceptions of randomness (the gambler’s fallacy or the hot-hand fallacy) would show differences in self-serving-bias through different levels of perceived control. In order to investigate this relationship between misperceptions of randomness, self-serving bias, and perceived control, the study manipulated perceived control by varying who threw the coin (experimenter/participant) and by showing a skill prime to some participants. Thus, in the experiment, participants either saw a skill prime or not by random assignment. Afterwards, the participants predicted an outcome, rated the confidence of the prediction, then the participants would throw a coin for half of the trials while the experimenter would for the other trials. Due to little variability of the self-serving bias, the analysis could not test the hypothesis. However, the study found that other variable such as confidence was able to predict the misperception of randomness when the participants threw the coin.