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RadixInsert, a much faster stable algorithm for sorting floating-point numbers
Get PDFThe problem addressed in this paper is that we want to sort an array a[] of n floating point numbers conforming to the IEEE 754 standard, both in the 64bit double precision and the 32bit single precision formats on a multi core computer with p real cores and shared memory (an ordinary PC). This we do by introducing a new stable, sorting algorithm, RadixInsert, both in a sequential version and with two parallel implementations. RadixInsert is tested on two different machines, a 2 core laptop and a 4 core desktop, outperforming the not stable Quicksort based algorithms from the Java library – both the sequential Arrays.sort() and a merge-based parallel version Arrays.parallelsort() for 500. The RadixInsert algorithm resembles in many ways the Shell sorting algorithm [1]. First, the array is pre-sorted to some degree – and in the case of Shell, Insertion sort is first used with long jumps and later shorter jumps along the array to ensure that small numbers end up near the start of the array and the larger ones towards the end. Finally, we perform a full insertion sort on the whole array to ensure correct sorting. RadixInsert first uses the ordinary right-to-left LSD Radix for sorting some left part of the floating-point numbers, then considered as integers. Finally, as with Shell sort, we perform a full Insertion sort on the whole array. This resembles in some ways a proposal by Sedgewick [10] for integer sorting and will be commented on later. The IEE754 standard was deliberately made such that positive floating-point numbers can be sorted as integers (both in the 32 and 64 bit format). The special case of a mix of positive and negative numbers is also handled in RadixInsert. One other main reason why Radix-sort is so well suited for this task is that the IEEE 754 standard normalizes numbers to the left side of the representation in a 64bit double or a 32bit float. The Radix algorithm will then in the same sorting on the leftmost bits in n floating-point numbers, sort both large and small numbers simultaneously. Finally, Radix is cache-friendly as it reads all its arrays left-to right with a small number of cache misses as a result, but writes them back in a different location in b[] in order to do the sorting. And thirdly, Radix-sort is a fast O(n) algorithm – faster than quicksort O(nlogn) or Shell sort O(n1.5). RadixInsert is in practice O(n), but as with Quicksort it might be possible to construct numbers where RadixInsert degenerates to an O(n2) algorithm. However, this worst case for RadixInsert was not found when sorting seven quite different distributions reported in this paper. Finally, the extra memory used by RadixInsert is n + some minor arrays whereas the sequential Quicksort in the Java library needs basically no extra memory. However, the merge based Arrays.parallelsort() in the Java library needs the same amount of n extra memory as RadixInsert
Translating 2D art into Virtual Reality and comparing the user experiences
Get PDFRecent advancements in virtual reality on the hardware and software front have made high-quality virtual reality experiences both cheaper, and easier to obtain. This paper explores how virtual reality changes the way a user experiences art and if virtual reality is suited as a medium for expressing art. Based on two existing artworks, we have created VR versions using a game engine, and conducted a user study to get a comparison of how the experience of the traditional artworks differ from the VR versions. The artworks have been created in 3D using algorithmic modelling techniques
Finite element method application of ERBS triangles
Get PDFIn this paper we solve an eigenvalue problem on a circular membrane with fixed outer boundary by using a finite element method, where an element is represented as an expo-rational blending triangle. ERBS triangles combine properties of B-spline finite elements and standard polynomial triangular elements. The overlapping of local triangles allows us to provide a flexible handling of the surface while preserving the smoothness of the initial domain, also over the nodes and edges. Blending splines accurately approximate the outer boundary, while keeping a coarse discretization of the domain. We consider a mesh construction for such type of elements, evaluating of basis functions and their directional derivatives, local-to-global mapping, assembling of element matrices
Datos para una historia compleja: normas curriculares y producciones editoriales: El caso argentino (1960–2014)
Get PDFI propose to present contributions to interpret the relations between curricular prescriptions of the Argentine primary education system and the textbooks, educational means that present courses or systematized subjects in the last five decades. Apart from a linear political and pedagogical reading, their stories show signs of congruent acceptance and development, as well as parallelism, “ascending” influences, productive exchanges, and merely formal acceptances. I justify the diachronic reading of these relations in the continuity of editorial productions, despite the social and political conflicts reflected in the changes of norms. I also consider the editorial contributions to curriculum policies, as well as their declines. We seek the intelligibility of intertextual relations in the complexity of the existence of curricular norms and textbooks, focusing on the interpretation of pedagogical approaches to norms and their development in the textbooks, in the articulation with aspects of the political context. I also propose to begin readings that link our history with that of international institutions relevant to research in the field of textbook research.Me propongo realizar algunos aportes para interpretar las relaciones entre las prescripciones curriculares del sistema educativo de nivel primario argentino y los libros de texto, medios educativos que desarrollan cursos o disciplinas sistematizadas, durante las últimas cinco décadas. El eje de reflexión general será la índole de las vinculaciones. Lejos de aparecer a la lectura política y pedagógica como lineales, sus historias muestran indicios de adopciones y desarrollos congruentes, así como también de paralelismos, influencias “ascendentes”, intercambios productivos y adopciones meramente formales. Justifico la lectura diacrónica de dichas relaciones en la continuidad de las producciones editoriales, a pesar de la conflictividad social y política reflejada en los cambios de normas. Considero también los aportes editoriales a las políticas curriculares, así como sus declinaciones. Se trata, en síntesis, de intentar una mayor inteligibilidad de las relaciones intertextuales en la complejidad de la coexistencia de normas curriculares y libros de texto. Los focos para proponer interpretaciones de esas relaciones son los enfoques pedagógicos de las normas y de sus desarrollos en los libros. Estas relaciones serán abordadas intentando perfilar algunos aspectos del contexto político que puedan contribuir a profundizar sus sentidos. También propongo iniciar lecturas que vinculen nuestra historia con las de instituciones internacionales relevantes por su aporte a la investigación manualística.Proponho apresentar aportes para interpretar as relações entre prescrições curriculares do sistema educativo primário argentino e os livros didáticos, meios educativos que apresentam cursos ou disciplinas sistematizadas nas últimas cinco décadas. Distanciadas de uma leitura política e pedagógica linear, suas histórias mostram indícios de aceitações e desenvolvimentos congruentes, bem como de paralelismos, influências “ascendentes”, intercâmbios produtivos e aceitações meramente formais. Justifico a leitura diacrônica dessas relações na continuidade das produções editoriais, apesar dos conflitos de ordem social e política refletidos nas mudanças de normas. Considero também as contribuições editoriais para as políticas curriculares, bem como seus declínios. Busca-se a inteligibilidade das relações intertextuais na complexidade da existência de normas curriculares e livros didáticos, focalizando na interpretação os enfoques pedagógicos das normas e seu desenvolvimento nos livros, na articulação com aspectos do contexto político. Proponho também dar início a leituras que vinculem nossa história com a de instituições internacionais relevantes para a investigação no campo da manualística
Some methods of problem solving in historical mathematical textbooks
Get PDFThis paper makes an excursion into the history of mathematics as presented in mathematics textbooks. We describe some components of mathematical notions in textbooks by Jakub Kresa (1648-1715) as well as some approaches to the problem solving in textbooks by Franz Mo?nik (1814-1892). These historical approaches are connected to modern mathematics education because many international studies, such as The Programme for International Student Assessment (PISA) support the use of problem solving and real-life problems in mathematics education. Word tasks have an important place in school mathematics. There are three important stages for solving these tasks: mathematization, calculation and interpretation of the tasks’ results. We also highlight divergent thinking in problem solving during the educational process.Este artículo hace un recorrido por la historia de las matemáticas presentada en los libros de matemáticas. Describimos algunos componentes de las nociones matemáticas en los libros didácticos escritos por Jakub Kresa (1648-1715), así como algunos enfoques para la resolución de problemas en los libros didácticos escritos por Franz Mo?nik (1814-1892). Estos enfoques históricos se conectan con la educación matemática moderna porque muchos estudios internacionales, como el Programa Internacional de Evaluación de Estudiantes (PISA), apoyan el uso de la resolución de problemas y los problemas de la vida real en la educación matemática. Las tareas con palabras tienen un lugar importante en las matemáticas escolares. Hay tres pasos importantes para resolver estas tareas: matematización, cálculo e interpretación de los resultados de las tareas. También destacamos el pensamiento divergente en la resolución de problemas durante el proceso educativo.Este artigo faz um percurso na história da matemática apresentada em livros de matemática. Descrevemos alguns componentes de noções matemáticas em livros didáticos de autoria de Jakub Kresa (1648-1715), bem como algumas abordagens para a resolução de problemas em livros didáticos de autoria de Franz Mo?nik (1814- 1892). Essas abordagens históricas se conectam à educação matemática moderna porque muitos estudos internacionais, como o Programa de Avaliação Internacional de Estudantes (PISA), apoiam o uso de resolução de problemas e de problemas da vida real na educação matemática. Tarefas com palavras têm um lugar importante na matemática escolar. Existem três etapas importantes para resolver essas tarefas: matematização, cálculo e interpretação dos resultados das tarefas. Também destacamos o pensamento divergente na resolução de problemas durante o processo educacional
How the textbook is inserted in the pedagogical practice of Biology high school teachers in Sobradinho, Distrito Federal, Brazil
Get PDFTextbooks have been present in teaching practices for a long time. It is commonplace to find students and teachers carrying several textbooks to school every day. However, does their presence in classes ensure their use? What roles do they play? Textbooks are teaching resources that are freely distributed by the Brazilian Federal government to public school students, by the National Textbook Program (Programa Nacional do Livro Didático - PNLD) and teachers choose the books to be delivered to their schools. These were factors that motivated the research about if these books become part of the teacher’s pedagogic practice and, if confirmed, how. Observations were made during biology lessons in some high schools in Sobradinho, Federal District (central Brazil), and questionnaires were distributed to the teachers, who were interviewed. The results show that the use of biology textbooks by teachers was restricted to planning the activities to be developed during the classes, thus pointing to their underutilisation in classrooms. Teachers do not often use the teacher’s guide, instrument that is part of the textbook. More studies about this subject are necessary in the teaching of biologyOs livros didáticos estão presentes no ensino há muito tempo. É comum encontrar estudantes e professores carregando vários livros didáticos todos os dias para a escola, mas a presença deles nas aulas garante seu uso? Quais papéis eles desempenham? Os livros didáticos são recursos distribuídos gratuitamente pelo governo federal para estudantes de escolas públicas pelo Programa Nacional do Livro Didático e os professores podem escolher os livros que são entregues às escolas. Esses foram os fatores que motivaram a pesquisa sobre se e como esses livros se tornam parte da prática pedagógica do professor e, se confirmados, como. Observações foram feitas durante aulas de biologia em algumas escolas de ensino médio em Sobradinho, Distrito Federal, e foram distribuídos questionários aos professores entrevistados. Os resultados mostram que o uso de livros didáticos de biologia pelos professores se restringiu ao planejamento das atividades desenvolvidas durante a aula, apontando, assim, para sua subutilização nas salas de aula. Os professores não costumam usar o manual do professor, instrumento que faz parte do livro didático. Mais estudos sobre esse assunto são necessários no ensino de biologia.Los libros de texto están presentes en la enseñanza desde hace mucho tiempo. Es común encontrar estudiantes y profesores cargando varios libros de texto todos los días para la escuela, pero su presencia en las clases garantiza su uso? ¿Qué roles desempeñan? Los libros de texto son recursos distribuidos gratuitamente por el gobierno federal para estudiantes de escuelas públicas, por el Programa Nacional del Libro Didáctico y los profesores pueden elegir los libros que se entregan para las escuelas. Estos fueron los factores que motivaron la investigación sobre si y cómo esos libros se convierten en parte de la práctica pedagógica del profesor y, si se confirman, ¿como?. Las observaciones fueron realizadas durante clases de biología en algunas escuelas de enseñanza secundaria en Sobradinho, Districto Federal, y se distribuyeron cuestionarios a los profesores entrevistados. Los resultados muestran que el uso de los libros de texto de biología por los profesores se restringió a la planificación de las actividades desarrolladas durante la clase, apuntando así a su infrautilización en las aulas. Los profesores no suelen usar el manual del profesor, instrumento que forma parte del libro de texto en el Programa Nacional. Más estudios sobre este tema son necesarios en la enseñanza de la biología
Unveiling the Data Shadow: A Scalable Software Architecture for Public Health and Electronically Assessed Data
Get PDFIn 2017, health expenditure in Norway amounted to 10,4 percent of GDP, and it increases by approx. 0,3 percent annually. Medical treatment and rehabilitation include treatment in hospitals, medical services, dental services, etc., and about half of Norway's health expenses are related to these services. In total, 97 percent of the budget is spent on treating disorders and support functions. Despite studies have shown that the greatest effect on health is within preventive health, only 3 percent of the Norwegian health expenses is used for that purpose. Computer-based technology is used to measure a large amount of health-related information as activity level, heartrate, sleep rhythms, eating habits, exercise habits and emotions. These large amounts of data collected by patients are available in electronic recording equipment and social media but are not shared with the physician or other healthcare professionals – in fact establishing a data shadow. The volume of data is massive, and health personnel do not know how to break the data down to sensible and usable information. This research project is founded in this perspective of preventive health and synthesizes available personal health information by utilizing commodity mobile and wearable hardware to gain a comprehensive insight into the health data shadow of an individual. This is further used to give individuals a fact-based awareness of own health and make informed choices, showcased through a persuasive technologies experiment, and secondly by a built prototype solution upon which health workers and medical doctors can be provided with a comprehensive, unfiltered data foundation to base diagnoses, treatment and council upon. Our major contribution is a proof of concept implementation and leveraging state of the art cloud based function as a service approach to build a scalable software architecture for a ubiquitous and heterogeneous environment harvesting the data shadow through activity tracking devices
Evaluating Population Based Training on Small Datasets
Get PDFRecently, there has been an increased interest in using artificial neural networks in the severely resource-constrained devices found in Internet-of-Things networks, in order to perform actions learned from the raw sensor data gathered by these devices. Unfortunately, training neural networks to achieve optimal prediction accuracy requires tuning multiple hyper-parameters, a process which has traditionally taken many times the computation time of a single training run of the neural network. In this paper, we empirically evaluate the Population Based Training algorithm, a method which simultaneously both trains and tunes a neural network, on datasets of similar size to what we might encounter in an IoT scenario. We determine that the population based training algorithm achieves prediction accuracy comparable to a traditional grid or random search on small datasets, and achieves state-of-the-art results for the Biodeg dataset
Pass/Fail Grading and Educational Practices in Computer Science
Get PDFBinary (pass/fail) grading have been shown to have benefits with respect to mental health and collaboration, and is argued to promote a deep approach to learning. However, diverging results with respect to academic achievement suggests that the full benefits of binary grading are contingent on underlying factors, such as how the teaching and learning activities in the course are designed. We here present experiences and student feedback for an intermediate level course in computer science that is graded using pass/fail, and which is highly successful both in terms of of student enjoyment and academic achievement. Survey results also indicate that students apply a deeper learning approach towards the course than average. Drawing on examples and findings from this course, we argue that the following three practices makes a binary graded course in computer science successful: a) a sufficiently high bar for passing, b) clear course requirements, and c) the use of formative assessment