Looking for ontology in a search engine, one can find so many different approaches that it can be difficult to understand which field of research the subject belongs to and how it can be useful. The term ontology is employed within philosophy, computer science, and information science with different meanings. To take advantage of what ontology theories have to offer, one should understand what they address and where they come from. In information science, except for a few papers, there is no initiative toward clarifying what ontology really is and the connections that it fosters among different research fields. This article provides such a clarification. We begin by revisiting the meaning of the term in its original field, philosophy, to reach its current use in other research fields. We advocate that ontology is a genuine and relevant subject of research in information science. Finally, we conclude by offering our view of the opportunities for interdisciplinary research.

Resumo Os estudos sobre a organização da informação têm recebido cada vez mais importância à medida que o número crescente de fontes de dados disponíveis dificulta a recuperação da informação. Nos últimos anos, vários trabalhos têm INTRODUÇÃONos últimos anos, o aumento exponencial dos dados disponíveis tem conferido importância significativa às técnicas de organização da informação. Essas técnicas fazem parte de um corpo de disciplinas que busca melhorias no tratamento de dados, atuando na sua seleção, no seu processamento, na sua recuperação e na sua disseminação.Diversos tipos de estruturas são utilizados na organização da informação. Estruturas que se organizam a partir da utilização de termos são os arquivos de autoridade, glossários e dicionários. Estruturas que se organizam com a classificação e a criação de categorias são os cabeçalhos de assunto e os esquemas de classificação (ou taxonomias). As estruturas que se organizam a partir de conceitos e de seus relacionamentos são as ontologias, os tesaurus e as redes semânticas.Nos últimos anos, uma abordagem que tem recebido atenção é a utilização de ontologias na organização do conteúdo das fontes de dados. Uma ontologia é criada por especialistas e define as regras que regulam a combinação entre termos e relações em um domínio do conhecimento. Os usuários formulam consultas usando conceitos definidos pela ontologia. O que se busca, em última instância, são melhorias nos processos de recuperação da informação.Ontologias são utilizadas hoje em diversas áreas para organizar a informação (

He collaborates with Ontology Research Group at University at Buffalo, US, working on medical vocabularies. Currently, his research involves ontologies and information systems.

Inversion of positron annihilation lifetime spectroscopy, based on a neural network Hopfield model, is presented in this paper. From a previous reported density function for lysozyme in water a simulated spectrum, without the superposition of statistical fluctuation and spectrometer resolution effects, was generated. These results were taken as the exact results from which the neural network was trained. The precision of the inverted density function was analyzed taking into account the number of neurons and the learning time of the neural network. A fair agreement was obtained when comparing the neural network results with the exact results. For example, the maximum of the density function, with a precision of 0.4% for the percentual relative error, was obtained for 64 neurons.

Information and knowledge are true assets in modern organizations. In order to cope with the need to manage these assets, corporations have invested in a set of practices that are conventionally called knowledge management. This article presents a case study on the development and the evaluation of ontologies that was conducted within the scope of a knowledge management project undertaken by the second largest Brazilian energy utility. Ontologies have different applications and can be used in knowledge management, in information retrieval, and in information systems, to mention but a few. Within the information systems realm, ontologies are generally used as system models, but their usage has not been restricted to software development. We advocate that, once assessed as to its content, an ontology may provide benefits to corporate communication and, therefore, provide support to knowledge management initiatives. We expect to further contribute by describing possibilities for the application of ontologies within organizational environments.