Propagation of Policies in Rich Data Flows

Governing the life cycle of data on the web is a challenging issue for organisations and users. Data is distributed under certain policies that determine what actions are allowed and in which circumstances. Assessing what policies propagate to the output of a process is one crucial problem. Having a description of policies and data flow steps implies a huge number of propagation rules to be specified and computed (number of policies times number of actions). In this paper we provide a method to obtain an abstraction that allows to reduce the number of rules significantly. We use the Datanode ontology, a hierarchical organisation of the possible relations between data objects, to compact the knowledge base to a set of more abstract rules. After giving a definition of Policy Propagation Rule, we show (1) a methodology to abstract policy propagation rules based on an ontology, (2) how effective this methodology is when using the Datanode ontology, (3) how this ontology can evolve in order to better represent the behaviour of policy propagation rules

Folksonomies and clustering in the collaborative system CiteULike

We analyze CiteULike, an online collaborative tagging system where users bookmark and annotate scientific papers. Such a system can be naturally represented as a tripartite graph whose nodes represent papers, users and tags connected by individual tag assignments. The semantics of tags is studied here, in order to uncover the hidden relationships between tags. We find that the clustering coefficient reflects the semantical patterns among tags, providing useful ideas for the designing of more efficient methods of data classification and spam detection.Comment: 9 pages, 5 figures, iop style; corrected typo

Providing Alternative Declarative Descriptions for Entity Sets Using Parallel Concept Lattices

We propose an approach for modifying a declarative description of a set of entities (e.g., a SPARQL query) for the purpose of finding alternative declarative descriptions for the entities. Such a shift in representation can help to get new insights into the data, to discover related attributes, or to find a more concise description of the entities of interest. Allowing the alternative descriptions furthermore to be close approximations of the original entity set leads to more flexibility in finding such insights. Our approach is based on the construction of parallel formal concept lattices over different sets of attributes for the same entities. Between the formal concepts in the parallel lattices, we define mappings which constitute approximations of the extent of the concepts. In this paper, we formalise the idea of two types of mappings between parallel concept lattices, provide an implementation of these mappings and evaluate their ability to find alternative descriptions in a scenario of several real-world RDF data sets. In this scenario we use descriptions for entities based on RDF classes and seek for alternative representations based on properties associated with the entities

Conceptual Knowledge Processing with Formal Concept Analysis and Ontologies

Cimiano P, Stumme G, Hotho A, Tane J. Conceptual Knowledge Processing with Formal Concept Analysis and Ontologies. In: Eklund PW, ed. Concept Lattices, Second International Conference on Formal Concept Analysis, ICFCA 2004, Sydney, Australia, February 23-26, 2004, Proceedings. Lecture Notes in Computer Science, 2961. Springer; 2004: 189-207

Reverse Pivoting in Conceptual Information Systems

In database marketing, the behavior of customers is analyzed by studying the transactions they have performed. In order to get a global picture of the behavior of a customer, his single transactions have to be composed together. In On-Line Analytical Processing, this operation is known as reverse pivoting. With the ongoing data analysis process, reverse pivoting has to be repeated several times, usually requiring an implementation in SQL. In this paper, we present a construction for conceptual scales for reverse pivoting in Conceptual Information Systems, and also discuss the visualization. The construction allows the reuse of previously created queries without reprogramming and o#ers a visualization of the results by line diagrams