From ternary relationship to relational tables: a case against common beliefs

The transformation from n-ary relationships to a relational database schema has never been really fully analyzed. This paper presents one of the several ternary cases ignored by the ER-to-RM literature. The case shows that the following common belief is wrong: Given a set of FDs over a table resulting in a non-3NF situation, it is always possible to obtain a fully equivalent set of 3NF tables, without adding other restrictions than candidate keys and inclusion dependencies.Postprint (published version

Transforming N-ary relationships to database schemas: an old and forgotten problem

The N-ary relationships, have been traditionally a source of confusion and still are. One important source of confusion is that the term cardinality in a relationship has several interpretations, two of them being very popular. But none of the two approaches, nor the two together, allow us to express all the possible cardinality patterns. The transformations from all the possible relationships to database schemas have never been described by the existing literature. Using the 14 ternary patterns as example, we discuss these transformations particularly the transformations from the patterns ignored in the literature.Postprint (published version

Searching by approximate personal-name matching

We discuss the design, building and evaluation of a method to access theinformation of a person, using his name as a search key, even if it has deformations. We present a similarity function, the DEA function, based on the probabilities of the edit operations accordingly to the involved letters and their position, and using a variable threshold. The efficacy of DEA is quantitatively evaluated, without human relevance judgments, very superior to the efficacy of known methods. A very efficient approximate search technique for the DEA function is also presented based on a compacted trie-tree structure.Postprint (published version

“She didn’t ask me about my grandma”. Using process drama to explore issues of cultural exclusion and educational leadership.

Purpose – This purpose of this paper is to describe a collaborative project from the University of Waikato, Hamilton New Zealand, in which the authors used process drama to engage final year teaching students with complex issues of cultural diversity, enabling them to “grow into” different kinds of leadership positions in an imagined educational setting. The paper describes the project and makes a case for process drama as a means of providing opportunities for leadership and as a potent tool for learning about issues of social justice. Design/methodology/approach – The drama was based on a fictional scenario described by Hall and Bishop, where a beginner teacher (of European descent) unwittingly diminishes the experiences of Maori and other non-European children in her class. Using a three-phase process planning model and with facilitators in role alongside the students, the drama explored the scenario from all points of view. Students were encouraged to build empathy for the beginner teacher and for the children and also to explore the dilemma faced by the teacher's tutor in deciding whether, and how, to confront the teacher on the issue. Findings – Through the drama, students built a sense of empathy for all sides of the issue and engaged in deep thinking about the experience of cultural exclusion. The safety and distance provided by the drama “frame” spurred students to take leadership roles and “stand up” for issues of social justice. The authors suggest that through such dramas students gain skills and perspectives that they may carry into their professional lives. Research limitations/implications – The paper describes a small project, over one lesson with a specific group of students. More research is needed into the effectiveness of process drama as a sustained strategy for teacher education. Originality/value – This scenario explored in the drama has currency in Aotearoa New Zealand, where the population is increasingly culturally diverse, where underachievement of Maori students continues to be of concern, and where research has shown the centrality of teacher-student relations in raising educational achievement for Maori. The authors believe this paper makes a compelling case for the value of drama as a tool for student teachers to encounter social justice issues in a meaningful way, and suggest that the paper is a valuable contribution to more than one discipline, as it straddles the fields of professional practice and drama as pedagogy

Funciones de comparación de carácteres para APNM: la distancia DEA

A typical application of the ASM (Approximate String Matching) is the matching of personal names, as for example to search people in the DB of an Information System. Through the years, several similarity functions have been proposed:phonetic codes, simple edit distance, n-gram distances, etc.A typical application of the ASM (Approximate String Matching) is the matching of personal names, as for example to search people in the DB of an Information System. Through the years, several similarity functions have been proposed: phonetic codes, simple edit distance, n-gram distances, etc. In this report a function is presented, DEA, having substantially better efficacy than existing ones, and mainly oriented to spanish surnames. The DEA distance is an edit distance, with costs based on the probabilities of the operations, characters and positions. The distance threshold is defined as a function of the lenght of the string. The efficacy of DEA is evaluated objectively, without human relevance judgements.Postprint (published version