Efficient mining of association rules based on formal concept analysis

Association rules are a popular knowledge discovery technique for warehouse basket analysis. They indicate which items of the warehouse are frequently bought together. The problem of association rule mining has first been stated in 1993. Five years later, several research groups discovered that this problem has a strong connection to Formal Concept Analysis (FCA). In this survey, we will first introduce some basic ideas of this connection along a specific algorithm, TITANIC, and show how FCA helps in reducing the number of resulting rules without loss of information, before giving a general overview over the history and state of the art of applying FCA for association rule mining.

Algorithmic Computation of Formal Fourier Series

KAAD (Katholischer Akademischer Ausländer-Dienst)

Quality Criteria for Enterprise Modelling in the context of networked Enterprises

The capability for collaboration is a key success factor for networked enterprises. The paper introduces a methodology supporting the application of Enterprise Modelling in order to improve the maturity for collaboration. The methodology considers the current status of maturity for interoperability for deducing the right modelling approach. The approach is combined with quality criteria of the models in order to guide the modelling process. Both the deducing approach and the quality criteria are related to the levels of interoperability proposed by the ATHENA Interoperability Framework.

Farmers’ desired traits and selection criteria for maize varieties and their implications for maize breeding: A case study from KwaZulu-Natal Province, South Africa

Adoption of hybrids and improved varieties has remained low in the smallholder farming sector of South Africa, despite maize being the staple food crop for the majority of households. The objective of this study was to establish preferred maize characteristics by farmers which can be used as selection criteria by maize breeders in crop improvement. Data were collected from three villages of a selected smallholder farming area in South Africa using a survey covering 300 households and participatory rural appraisal methodology. Results indicated a limited selection of maize varieties grown by farmers in the area compared to other communities in Africa. More than 97% of the farmers grew a local landrace called Natal-8-row or IsiZulu. Hybrids and improved open pollinated varieties were planted by less than 40% of the farmers. The Natal-8-row landrace had characteristics similar to landraces from eastern and southern Africa and closely resembled Hickory King, a landrace still popular in Southern Africa. The local landrace was preferred for its taste, recycled seed, tolerance to abiotic stresses and yield stability. Preferred characteristics of maize varieties were high yield and prolificacy, disease resistance, early maturity, white grain colour, and drying and shelling qualities. Farmers were willing to grow hybrids if the cost of seed and other inputs were affordable and their preferences were considered. Our results show that breeding opportunities exist for improving the farmers’ local varieties and maize breeders can take advantage of these preferred traits and incorporate them into existing high yielding varieties.

Decent work?

Pastoralism and ranching are two different rangeland-based livestock systems in dryland areas of East Africa. Both usually operate under low and irregular rainfall and consequently low overall primary biomass production of high spatial and temporal heterogeneity. Both are usually located far from town centres, market outlets and communication, medical, educational, banking, insurance and other infrastructure. Whereas pastoralists can be regarded as self-employed, gaining their livelihood from managing their individually owned livestock on communal land, ranches mostly employ herders as wage labourers to manage the livestock owned by the ranch on the ranches’ own land property. Both production systems can be similarly labour intensive and – with regard to the livestock management – require the same type of work, whether carried out as self-employed pastoralist or as employed herder on a work contract. Given this similarity, the aim of this study was to comparatively assess how pastoralists and employed herders in northern Kenya view their working conditions, and which criteria they use to assess hardship and rewards in their daily work and their working life. Their own perception is compared with the concept of Decent Work developed by the International Labour Organisation (ILO). Samburu pastoralists in Marsabit and Samburu Districts as well as herders on ranches in Laikipia District were interviewed. A qualitative analysis of 47 semi-structured interviews yielded information about daily activities, income, free time, education and social security. Five out of 22 open interviews with pastoralists and seven out of 13 open interviews with employed herders fully transcribed and subjected to qualitative content analysis to yield life stories of 12 informants. Pastoralists consider it important to have healthy and satisfied animals. The ability to provide food for their family especially for the children has a high priority. Hardships for the pastoralists are, if activities are exhausting, and challenging, and dangerous. For employed herders, decent conditions are if their wages are high enough to be able to provide food for their family and formal education for their children. It is further most important for them to do work they are experienced and skilled in. Most employed herders were former pastoralists, who had lost their animals due to drought or raids. There are parallels between the ILO ‘Decent Work’ concept and the perception of working conditions of pastoralists and employed herders. These are, for example, that remuneration is of importance and the appreciation by either the employer or the community is desired. Some aspects that are seen as important by the ILO such as safety at work and healthy working conditions only play a secondary role to the pastoralists, who see risky and dangerous tasks as inherent characteristics of their efforts to gain a livelihood in their living environment.

Formal Multilevel Hierarchical Verification of Synchronous MOS Circuits

I have designed and implemented a system for the multilevel verification of synchronous MOS VLSI circuits. The system, called Silica Pithecus, accepts the schematic of an MOS circuit and a specification of the circuit's intended digital behavior. Silica Pithecus determines if the circuit meets its specification. If the circuit fails to meet its specification Silica Pithecus returns to the designer the reason for the failure. Unlike earlier verifiers which modelled primitives (e.g., transistors) as unidirectional digital devices, Silica Pithecus models primitives more realistically. Transistors are modelled as bidirectional devices of varying resistances, and nodes are modelled as capacitors. Silica Pithecus operates hierarchically, interactively, and incrementally. Major contributions of this research include a formal understanding of the relationship between different behavioral descriptions (e.g., signal, boolean, and arithmetic descriptions) of the same device, and a formalization of the relationship between the structure, behavior, and context of device. Given these formal structures my methods find sufficient conditions on the inputs of circuits which guarantee the correct operation of the circuit in the desired descriptive domain. These methods are algorithmic and complete. They also handle complex phenomena such as races and charge sharing. Informal notions such as races and hazards are shown to be derivable from the correctness conditions used by my methods.

Familia y educación formal : implicación de la familia en el proceso de enseñanza-aprendizaje.

Examinar la importancia que concede la familia, padres e hijos, a la Educación Formal. Para ello analiza la implicación de los padres en el proceso de enseñanza-aprendizaje de los hijos explorando su conducta en algunas variables de proceso familiar relativas al estudio y sondea, al mismo tiempo, la conducta que los hijos esperan de ellos. Pretende identificar aspectos de proceso familiar relativos al estudio donde padres e hijos muestren concordancia y discrepancia. Alumnos de séptimo de EGB y sus padres de 4 centros públicos de Oviedo, de dos zonas diferenciadas de la ciudad, elegidos dentro de cada zona según la posibilidad de acceso a los mismos, por lo que la muestra no es aleatoria. El número de alumnos fue el de dos aulas pero no siempre fueron los mismos sujetos en las tres aplicaciones del cuestionario. Variables procesuales (intereses, comportamientos) y evaluativas-perceptivas (actitudes, expectativas, percepciones) relativas al estudio, examinadas en padres y en hijos que, en conjunto, informan sobre las formas de implicación de los padres en el proceso de enseñanza-aprendizaje de los hijos y las formas de implicación de los padres esperadas por los hijos en dicho proceso. Variables de clasificación de dos tipos: estructurales como el nivel de estudios de los padres y de producto como el rendimiento escolar. Cuestionario ad hoc y entrevistas semiestructuradas a padres, con preguntas sobre intereses, actitudes, opiniones y expectativas. Los padres mantienen un nivel de implicación considerable sobre todo en las cuestiones referidas a actitudes, comportamiento que es esperado por los hijos. No todos los hijos esperan que sus padres se impliquen en aspectos de tipo afectivo y material del modo tan frencuente en que los hacen. A pesar de la coincidencia entre ellos, hay variables en las que los hijos esperan mayor implicación que el mostrado por sus padres como en aspectos relacionales, control del estudio diario, etc. La tipología de las variables relevantes en ambos colectivos, los aspectos intelectuales-culturales, cognitivo-perceptivos y de estatus son los mas asociados al rendimiento escolar. Padres e hijos conceden un gran valor a la educación formal. Ello lleva a los padres a implicarse en el proceso de enseñanza-aprendizaje y a los hijos a demandar esa implicación. Las formas de implicación suelen ser comunes entre padres e hijos por lo que se podría hablar de pautas de conducta configuradas en un contexto social, e incluso de pautas de conducta familiar. A la vista de los resultados se ofrece una serie de orientaciones y prácticas educativas que pueden ser relevantes para profesores, padres o alumnos.

Refinement criteria for global illumination using convex funcions

In several computer graphics areas, a refinement criterion is often needed to decide whether to go on or to stop sampling a signal. When the sampled values are homogeneous enough, we assume that they represent the signal fairly well and we do not need further refinement, otherwise more samples are required, possibly with adaptive subdivision of the domain. For this purpose, a criterion which is very sensitive to variability is necessary. In this paper, we present a family of discrimination measures, the f-divergences, meeting this requirement. These convex functions have been well studied and successfully applied to image processing and several areas of engineering. Two applications to global illumination are shown: oracles for hierarchical radiosity and criteria for adaptive refinement in ray-tracing. We obtain significantly better results than with classic criteria, showing that f-divergences are worth further investigation in computer graphics. Also a discrimination measure based on entropy of the samples for refinement in ray-tracing is introduced. The recursive decomposition of entropy provides us with a natural method to deal with the adaptive subdivision of the sampling region

Material didáctico de educación ambiental no formal para el programa “yo, sí puedo cuidar el ambiente”, en Nicaragua

El presente trabajo ha consistido en elaborar el material didáctico para la educación ambiental no formal de los ciudadanos de Nicaragua, con nivel escolar equivalente a sexto grado. Este material en un futuro cercano será la base del programa de alfabetización ambiental “Yo, Sí Puedo Cuidar el Ambiente”,coordinado por la “Red Universitaria Yo, Sí Puedo” en distintas partes de Nicaragua. El resultado del proyecto es una cartilla destinada al alumno y una Guía Metodológica para el educador. Para la realización de este proyecto ha sido necesaria una estancia de tres meses y medio para la recopilación de información y la elaboración de material didáctico. El principal objetivo del material elaborado es contribuir en la sensibilización y la formación de valotres ambientales de los participantes, mejorando asi su calidad de vida y su entorno

How to improve the formal analytic reasoning and scientific motivation in the intellectual training of medical students

A review article of the The New England Journal of Medicine refers that almost a century ago, Abraham Flexner, a research scholar at the Carnegie Foundation for the Advancement of Teaching, undertook an assessment of medical education in 155 medical schools in operation in the United States and Canada. Flexner’s report emphasized the nonscientific approach of American medical schools to preparation for the profession, which contrasted with the university-based system of medical education in Germany. At the core of Flexner’s view was the notion that formal analytic reasoning, the kind of thinking integral to the natural sciences, should hold pride of place in the intellectual training of physicians. This idea was pioneered at Harvard University, the University of Michigan, and the University of Pennsylvania in the 1880s, but was most fully expressed in the educational program at Johns Hopkins University, which Flexner regarded as the ideal for medical education. (...)

Educaci??n formal, no formal e informal en el Espacio Europeo : nuevas exigencias para los procesos de formaci??n en educaci??n

Resumen tomado de la publicaci??n

El Aprendizaje del derecho inglés en modo cooperativo formal

En primer curso de Derecho económico de la Universidad de Vigo, se planteó la posibilidad de llevar a cabo un proyecto piloto de aprendizaje cooperativo. Nos pareció interesante la idea y propusimos que la asignatura “Introducción a los Sistemas Jurídicos” se impartiese en aprendizaje cooperativo formal, como requisito previo a la realización de un examen final. Nuestro objetivo era conseguir una mayor implicación del discente en su propio proceso de aprendizaje, al mismo tiempo que la adquisición de determinadas destrezas necesarias en el ámbito jurídico, como la interacción cara a cara, la interdependencia positiva, la responsabilidad personal, el saber desenvolverse en público y la capacidad de autoanálisis o evaluación de los resultados del grupo. En este caso concreto, era necesario dotar de las destrezas necesarias a los discentes para que el aprendizaje del Derecho Inglés, como sistema jurídico diferente al nuestro, resultase atractivo y suscitase el interés de los estudiantes a la hora de abordar el conocimiento del Common Law. La diferencia fundamental, reflejada en "Judge made Law", en referencia a la labor creadora del derecho que realizan los jueces en el mundo jurídico anglosajón, puede ser explicada mucho mejor en un contexto de creatividad como el que ofrece una metodología docente activa como es el Aprendizaje Cooperativo, y por ello resultó elegida. Elegimos el Aprendizaje Cooperativo Formal porque nos pareció adecuada su vocación de continuidad, en el sentido de formar grupos para una determinada tarea que puede durar desde una clase a varias semanas. En un grupo formal los estudiantes trabajan juntos para conseguir objetivos compartidos, intentando maximizar su aprendizaje y el de sus propios compañeros. El número de miembros que conforman un grupo formal es pequeño, 2 o 4 estudiantes, organizado por el profesor, a menudo al azar, y en ellos se espera que el estudiante interaccione con sus compañeros, compartiendo los conceptos y estrategias que aprendan, y que se consideren mutuamente responsables de la tarea asignada, acudiendo sólo en último término al profesor en caso de dudas. Pero teníamos dudas con respecto a la realidad del proyecto, por el elevado número de estudiantes en el grupo de “Introducción a los Sistemas Jurídicos”. Con todo, la ilusión y un gran esfuerzo hicieron posible llevar a cabo el proyecto previsto, y los resultados fueron totalmente positivos

La educaci??n formal de los hijos e hijas de familias homoparentales : familia y escuela a contracorriente

Resumen tomado de la publicaci??n

Pensamiento formal y resoluci??n de problemas matem??ticos

Resumen tomado de la publicaci??n