Using the Optical Mouse Sensor as a Two-Euro Counterfeit Coin Detector

In this paper, the sensor of an optical mouse is presented as a counterfeit coin detector applied to the two-Euro case. The detection process is based on the short distance image acquisition capabilities of the optical mouse sensor where partial images of the coin under analysis are compared with some partial reference coin images for matching. Results show that, using only the vision sense, the counterfeit acceptance and rejection rates are very similar to those of a trained user and better than those of an untrained user

Modelling recursion

The purpose of my research is to examine and explore the ways that undergraduate students understand the concept of recursion. In order to do this, I have designed computer-based software, which provides students with a virtual and interactive environment where they can explore the concept of recursion, and demonstrate and develop their knowledge of recursion through active engagement. I have designed this computer-based software environment with the aim of investigating how students think about recursion. My approach is to design digital tools to facilitate students' understanding of recursion and to expose that thinking. My research investigates students' understanding of the hidden layers and inherent complexity of recursion, including how they apply it within relevant contexts. The software design embedded the idea of functional abstraction around two basic principles of: 'functioning' and 'functionality'. The functionality principle focuses on what recursion achieve, and the functioning dimension concerns how recursion is operationalised. I wanted to answer the following crucial question: How does the recursive thinking of university students evolve through using carefully designed digital tools? In the process of exploring this main question, other questions emerged: 1. Do students understand the difference between recursion and iteration? 2. How is tail and embedded recursion understood by the students? 3. To what extent does prior knowledge of the concept of iteration influence students' understanding of tail and embedded recursion? 4. Why is it important to have a clear understanding of the control passing mechanisms in order to understand recursion? 5. What is the role of functional abstraction in both, the design of computer-based tools and the students' understanding of recursion? 6. How are students' mental models of recursion shaped by their engagement with computer-based tools? From a functional abstraction point of view almost all previous research into the concept of recursion has focused on the functionality dimension. Typically, it has focused on procedures for the calculation of the factorial of a natural number, and students were tested to see if they are able to work out the values of the a function recursively (Wiedenbeck, 1988; Anazi and Uesato, 1982) or if they are able to recognize a recursive structure (Sooriamurthi, 2001; Kurland and Pea, 1985). Also, I invented the Animative Visualisation in the Domain of Abstraction (AVDA) which combines the functioning and functionality principles regarding the concept of recursion. In the AVDA environment, students are given the opportunity to explore the hidden layers and the complicated behaviour of the control passing mechanisms of the concept of recursion. In addition, most of the textbooks in mathematics and computer sciences usually fail to explain how to use recursion to solve a problem. Although it is also true that text books do not typically explain how to use iteration to solve problems, students are able to draw on to facilitate solving iterative problems (Pirolli et al, 1988). My approach is inspired by how recursion can be found in everyday life and in real world phenomena, such as fractal-shaped objects like trees and spirals. This research strictly adheres to a Design Based Research methodology (DBR), which is founded on the principle of the cycle of designing, testing (observing the students' experiments with the design), analysing, and modifying (Barab and Squire, 2004; Cobb and diSessa, 2003). My study was implemented throughout three iterations. The results showed that in the AVDA (Animative Visualisation in the Domain of Abstraction) environment students' thinking about the concept of recursion changed significantly. In the AVDA environment they were able to see and experience the complicated control passing mechanism of the tail and embedded recursion, referred to a delegatory control passing. This complicated control passing mechanism is a kind of generalization of flow in the iterative procedures, which is discussed later in the thesis. My results show that, to model a spiral, students prefer to use iterative techniques, rather than tail recursion. The AVDA environment helped students to appreciate the delegatory control passing for tail recursive procedures. However, they still demonstrated difficulties in understanding embedded recursive procedures in modelling binary and ternary trees, particularly regarding the transition of flow between recursive calls. Based on the results of my research, I have devised a model of the evolution of students' mental model of recursion which I have called – the quasi-pyramid model. This model was derived from applying functional abstraction including both functionality and functioning principles. Pedagogic implications are discussed. For example, the teaching of recursion might adopt 'animative' visualization, which is of vitally important for students' understanding of latent layers of recursion

Feature-based methodology for supporting architecture refactoring and maintenance of long-life software systems

Zusammenfassung Langlebige Software-Systeme durchlaufen viele bedeutende Veraenderungen im Laufe ihres Lebenszyklus, um der Weiterentwicklung der Problemdomaenen zu folgen. Normalerweise ist es schwierig eine Software-Systemarchitektur den schnellen Weiterentwicklungen einer Problemdomaene anzupassen und mit der Zeit wird der Unterschied zwischen der Problemdomaene und der Software-Systemarchitektur zu groß, um weitere Softwareentwicklung sinnvoll fortzufuehren. Fristgerechte Refactorings der Systemarchitektur sind notwendig, um dieses Problem zu vermeiden. Aufgrund des verhaeltnismaeßig hohen Gefahrenpotenzials und des zeitlich stark verzoegerten Nutzens von Refactorings, werden diese Maßnahmen normalerweise bis zum letztmoeglichen Zeitpunkt hinausgeschoben. In der Regel ist das Management abgeneigt Architektur-Refactorings zu akzeptieren, außer diese sind absolut notwendig. Die bevorzugte Vorgehensweise ist, neue Systemmerkmale ad hoc hinzuzufuegen und nach dem Motto ”Aendere nie etwas an einem funktionierenden System!” vorzugehen. Letztlich ist das Ergebnis ein Architekturzerfall (Architekturdrift). Die Notwendigkeit kleiner Refactoring-Schritte fuehrt zur Notwendigkeit des Architektur-Reengineerings. Im Gegensatz zum Refactoring, das eine normale Entwicklungstaetigkeit darstellt, ist Reengineering eine Form der Software- ”Revolution”. Reengineeringprojekte sind sehr riskant und kostspielig. Der Nutzen des Reengineerings ist normalerweise nicht so hoch wie erwartet. Wenn nach dem Reengineering schließlich die erforderlichen Architekturaenderungen statt.nden, kann dies zu spaet sein. Trotz der enormen in das Projekt gesteckten Bemuehungen erfuellen die Resultate des Reengineerings normalerweise nicht die Erwartungen. Es kann passieren, dass sehr bald ein neues, kostspieliges Reengineering erforderlich wird. In dieser Arbeit werden das Problem der Softwareevolution und der Zerfall von Softwarearchitekturen behandelt. Eine Methode wird vorgestellt, welche die Softwareentwicklung in ihrer entscheidenden Phase, dem Architekturrefactoring, unterstuetzt. Die Softwareentwicklung wird sowohl in technischer als auch organisatorischer Hinsicht unterstuetzt. Diese Arbeit hat neue Techniken entwickelt, welche die Reverse-Engineering-, Architecture-Recovery- und Architecture-Redesign-Taetigkeiten unterst uetzen. Sie schlaegt auch Aenderungen des Softwareentwicklungsprozesses vor, die fristgerechte Architekturrefactorings erzwingen koennen und damit die Notwendigkeit der Durchfuehrung eines Architektur- Reengineerings vermeiden. In dieser Arbeit wird die Merkmalmodellierung als Hauptinstrument verwendet. Merkmale werden genutzt, um die Abstraktionsluecke zwischen den Anforderungen der Problemdomaene und der Systemarchitektur zu fuellen. Merkmalmodelle werden auch als erster Grundriss fr die Wiederherstellung der verlorenen Systemarchitektur genutzt. Merkmalbasierte Analysen fuehren zu diversen, nuetzlichen Hinweisen fuer den erneuten Entwurf (das Re-Design) einer Architektur. Schließlich wird die Merkmalmodellierung als Kommunikationsmittel zwischen unterschiedlichen Projektbeteiligten (Stakeholdern) im Verlauf des Softwareengineering-Prozesses verwendet und auf dieser Grundlage wird ein neuer Anforderungsde.nitionsprozess vorgeschlagen, der die erforderlichen Architekturrefactorings erzwingt.The long-life software systems withstand many significant changes throughout their life-cycle in order to follow the evolution of the problem domains. Usually, the software system architecture can not follow the rapid evolution of a problem domain and with time, the diversion of the architecture in respect to the domain features becomes prohibiting for software evolution. For avoiding this problem, periodical refactorings of the system architecture are required. Usually, architecture refactorings are postponed until the very last moment, because of the relatively high risk involved and the lack of short-term profit. As a rule, the management is unwilling to accept architecture refactorings unless they become absolutely necessary. The preferred way of working is to add new system features in an ad-hoc manner and to keep the rule ”Never touch a running system!”. The final result is an architecture decay. The need of performing small refactoring activities turns into need for architecture reengineering. In contrast to refactoring, which is a normal evolutionary activity, reengineering is a kind of software ”revolution”. Reengineering projects are risky and expensive. The effectiveness of reengineering is also usually not as high as expected. When finally after reengineering the required architecture changes take place, it can be too late. Despite the enormous invested efforts, the results of the reengineering usually do not satisfy the expectations. It might happen that very soon a new expensive reengineering is required. This thesis deals with the problem of software evolution and the decay of software architectures. It presents a method, which assists software evolution in its crucial part, the architecture refactoring. The assistance is performed for both technical and organizational aspects of the software evolution. The thesis provides new techniques for supporting reverse engineering, architecture recovery and redesigning activities. It also proposes changes to the software engineering process, which can force timely architecture refactorings and thus avoid the need of performing architecture reengineering. For the work in this thesis feature modeling is utilized as a main asset. Features are used to fill the abstraction gap between domain requirements and system architecture. Feature models are also used as an outline for recovering of lost system architectures. Through feature-based analyses a number of useful hints and clues for architecture redesign are produced. Finally, feature modeling is used as a communication between different stakeholders of the software engineering process and on this basis a new requirements engineering process is proposed, which forces the needed architecture refactorings

Mathematical education of young and adults: pedagogical implications of historical-cultural theory

Educação matemática de jovens e adultos: implicações pedagógicas da teoria histórico-cultural O presente estudo aborda algumas implicações pedagógicas da teoria histórico-cultural para a exploração de ideias matemáticas no âmbito da educação de jovens e adultos (EJA). Partindo de uma análise sobre o estado da arte no que se refere às dificuldades de professores e alunos para o ensino e a aprendizagem da Matemática ao longo do processo de escolarização indica elementos ao debate que se voltam à explicação dos problemas elencados e para encaminhamento de um processo de constituição de sujeitos de aprendizagem matemática no âmbito da EJA. Trata-se de pesquisa bibliográfica e documental, além da análise de situações matemáticas usuais em aulas de EJA, cujos resultados mostram as dificuldades da cultura escolar básica para a superação de ações didáticas ainda fortemente marcadas pela associação de modelos. Aponta para o constructo teórico da perspectiva histórico-cultural como perspectiva para a efetivação de um amplo processo de produção de sentidos e de negociação de significados de ensino e de aprendizagem da Matemática na EJA. Palavras-chave: Educação de Jovens e Adultos, EJA, Educação Matemática, Formação de Conceitos, Produção de Sentidos, Negociação de Significados Matemáticos.   Mathematical education of young and adults: pedagogical implications of historical-cultural theory ABSTRACT: The present study addresses some pedagogical implications of historical-cultural theory for the exploration of mathematical ideas in the field of youth and adult education (EJA). Starting from an analysis of the state of the art regarding the difficulties of teachers and students for teaching and learning of Mathematics throughout the schooling process indicates elements to the debate that return to the explanation of the problems listed and to refer a process of constitution of mathematical learning subjects within the scope of the EJA. It is a bibliographical and documentary research, besides the analysis of usual mathematical situations in EJA classes, whose results show the difficulties of the basic school culture to overcome didactic actions still strongly marked by the association of models. It points to the theoretical construct of the historical-cultural perspective as a perspective for the realization of a broad process of production of meanings and negotiation of meanings of teaching and learning of Mathematics in the EJA. Keywords: Youth and Adult Education, EJA, Mathematical Education, Formation of Concepts, Production of Meanings, Negotiation of Mathematical Meanings.   Educación matemática de jóvenes y adultos: implicaciones pedagógicas de La teoría histórico-cultural RESUMEN. El presente estudio aborda algunas implicaciones pedagógicas de la teoría histórico-cultural para la exploración de ideas matemáticas en el ámbito de la educación de jóvenes y adultos (EJA). A partir de un análisis sobre el estado del arte en lo que se refiere a las dificultades de profesores y alumnos para la enseñanza y el aprendizaje de las Matemáticas a lo largo del proceso de escolarización indica elementos al debate que se vuelven a la explicación de los problemas enumerados y para encaminamiento de un proceso el proceso de constitución de sujetos de aprendizaje matemático en el marco de la EJA. Se trata de una investigación bibliográfica y documental, además del análisis de situaciones matemáticas usuales en clases de EJA, cuyos resultados muestran las dificultades de la cultura escolar básica para la superación de acciones didácticas aún fuertemente marcadas por la asociación de modelos. Se apunta al constructo teórico de la perspectiva histórico-cultural como perspectiva para la efectividad de un amplio proceso de producción de sentidos y de negociación de significados de enseñanza y de aprendizaje de las Matemáticas en la EJA. Palabras clave: Educación de Jóvenes y Adultos, EJA, Educación Matemática, Formación de Conceptos, Producción de Sentidos, Negociación de Significados Matemáticos

Analyse et recherche d'oeuvres d'art 2D selon le contenu pictural

État de l'art des méthodes manuelles et automatiques d'analyse des oeuvres d'art 2D -- Recherche d'images selon l'organisation spatiale des couleurs -- Seuil automatique pour la recherche d'images selon l'OSC -- Extraction des contours des traits -- Analyse de l'impact pictural dans les oeuvres au trait -- Conclusion et perspectives

AutoGraff: towards a computational understanding of graffiti writing and related art forms.

The aim of this thesis is to develop a system that generates letters and pictures with a style that is immediately recognizable as graffiti art or calligraphy. The proposed system can be used similarly to, and in tight integration with, conventional computer-aided geometric design tools and can be used to generate synthetic graffiti content for urban environments in games and in movies, and to guide robotic or fabrication systems that can materialise the output of the system with physical drawing media. The thesis is divided into two main parts. The first part describes a set of stroke primitives, building blocks that can be combined to generate different designs that resemble graffiti or calligraphy. These primitives mimic the process typically used to design graffiti letters and exploit well known principles of motor control to model the way in which an artist moves when incrementally tracing stylised letter forms. The second part demonstrates how these stroke primitives can be automatically recovered from input geometry defined in vector form, such as the digitised traces of writing made by a user, or the glyph outlines in a font. This procedure converts the input geometry into a seed that can be transformed into a variety of calligraphic and graffiti stylisations, which depend on parametric variations of the strokes

EXTRACTING FLOW FEATURES USING BAG-OF-FEATURES AND SUPERVISED LEARNING TECHNIQUES

Measuring the similarity between two streamlines is fundamental to many important flow data analysis and visualization tasks such as feature detection, pattern querying and streamline clustering. This dissertation presents a novel streamline similarity measure inspired by the bag-of-features concept from computer vision. Different from other streamline similarity measures, the proposed one considers both the distribution of and the distances among features along a streamline. The proposed measure is tested in two common tasks in vector field exploration: streamline similarity query and streamline clustering. Compared with a recent streamline similarity measure, the proposed measure allows users to see the interesting features more clearly in a complicated vector field. In addition to focusing on similar streamlines through streamline similarity query or clustering, users sometimes want to group and see similar features from different streamlines. For example, it is useful to find all the spirals contained in different streamlines and present them to users. To this end, this dissertation proposes to segment each streamline into different features. This problem has not been studied extensively in flow visualization. For instance, many flow feature extraction techniques segment streamline based on simple heuristics such as accumulative curvature or arc length, and, as a result, the segments they found usually do not directly correspond to complete flow features. This dissertation proposes a machine learning-based streamline segmentation algorithm to segment each streamline into distinct features. It is shown that the proposed method can locate interesting features (e.g., a spiral in a streamline) more accurately than some other flow feature extraction methods. Since streamlines are space curves, the proposed method also serves as a general curve segmentation method and may be applied in other fields such as computer vision. Besides flow visualization, a pedagogical visualization tool DTEvisual for teaching access control is also discussed in this dissertation. Domain Type Enforcement (DTE) is a powerful abstraction for teaching students about modern models of access control in operating systems. With DTEvisual, students have an environment for visualizing a DTE-based policy using graphs, visually modifying the policy, and animating the common DTE queries in real time. A user study of DTEvisual suggests that the tool is helpful for students to understand DTE

Proceedings of the second "international Traveling Workshop on Interactions between Sparse models and Technology" (iTWIST'14)

The implicit objective of the biennial "international - Traveling Workshop on Interactions between Sparse models and Technology" (iTWIST) is to foster collaboration between international scientific teams by disseminating ideas through both specific oral/poster presentations and free discussions. For its second edition, the iTWIST workshop took place in the medieval and picturesque town of Namur in Belgium, from Wednesday August 27th till Friday August 29th, 2014. The workshop was conveniently located in "The Arsenal" building within walking distance of both hotels and town center. iTWIST'14 has gathered about 70 international participants and has featured 9 invited talks, 10 oral presentations, and 14 posters on the following themes, all related to the theory, application and generalization of the "sparsity paradigm": Sparsity-driven data sensing and processing; Union of low dimensional subspaces; Beyond linear and convex inverse problem; Matrix/manifold/graph sensing/processing; Blind inverse problems and dictionary learning; Sparsity and computational neuroscience; Information theory, geometry and randomness; Complexity/accuracy tradeoffs in numerical methods; Sparsity? What's next?; Sparse machine learning and inference.Comment: 69 pages, 24 extended abstracts, iTWIST'14 website: http://sites.google.com/site/itwist1

Of evolution, information, vitalism and entropy: reflections of the history of science and epistemology in the works of Balzac, Zola, Queneau, and Houellebecq

This dissertation proposes the application of rarely-used epistemological and scientific lenses to the works of four authors spanning two centuries: Honoré de Balzac, Émile Zola, Raymond Queneau, and Michel Houellebecq. Each of these novelists engaged closely with questions of science and epistemology, yet each approached that engagement from a different scientific perspective and epistemological moment. In Balzac’s La Peau de chagrin, limits of determinism and experimental method tend to demonstrate that there remains an inscrutable yet guided excess in the interactions between the protagonist Raphaël and his enchanted skin. This speaks to an embodiment of the esprit préscientifique, a framework that minimizes the utility of scientific practice in favor of the unresolved mystery of vitalism. With Zola comes a move away from undefinable mystery to a construction of the novel consistent with Claude Bernard’s deterministic experimental medicine. Yet Zola’s Roman expérimental project is only partially executed, in that the Newtonian framework that underlies Bernard’s method yields to contrary evidence in Zola’s text of entropy, error, and loss of information consistent with the field of thermodynamics. In Queneau’s texts, Zola’s interest in current science not only remains, but is updated to reflect the massive upheaval in scientific thought that took place in the last half of the nineteenth and early part of the twentieth centuries. If Queneau’s texts explicitly mention advances like relativity, however, they often do so in a humorously dismissive manner that values pre-entropic and even early geometric constructs like perpetual motion machines and squared circles. Queneau’s apparent return to the pre-scientific ultimately yields to Houellebecq’s textual abyss. For Houellebecq, science is not only to be embraced in its entropic and relativistic constructs; it is these very constructs - and the style typically used to present them – that serve as a reminder of the abjection, decay, and hopelessness of human existence. Gone is the mystery of life in its totality. In its place remain humans acting as a series of particles mechanically obeying deterministic laws. The parenthesis that opened with Balzac’s positive coding of pre-scientific thought closes with Houellebecq’s negative coding of modern scientific theory