Data Warehouses and on-line analytical processing (OLAP) systems are a promising area for the application of Abstract State Machines (ASMs). In this paper a ground model specification for data warehouses is sketched that is based on the fundamental idea of separating input from operational databases and output to OLAP systems. On this basis we start defining formal refinement rules for such sys...

Differently from OLTP workloads, OLAP workloads are hardly predictable due to their inherently extemporary nature. Besides, obtaining real OLAP workloads by monitoring the queries actually issued in companies and organizations is quite hard. On the other hand, hardware and software benchmarking in the industrial world, as well as comparative evaluation of novel approaches in the research commun...

Résumé. Les systèmes décisionnels reposent sur des bases de données multidimensionnelles qui offrent un cadre adéquat aux analyses OLAP. L’article présente un nouvel opérateur OLAP nommé « BLEND » rendant possible des analyses multigraduelles. Il s'agit de transformer la structuration multidimensionnelle lors des interrogations pour analyser les mesures selon des niveaux de granularité différen...

Résumé — les systèmes OLAP facilitent l’analyse en offrant un espace multidimensionnelle des données que les décideurs explorent interactivement par une succession d’opérations Olap. Cependant ces systèmes OLAP sont élaborés pour un groupe de décideurs ou un sujet d’analyse « subject-oriented », pour lesquels sont présumés des besoins parfaitement identiques. Ce qui les rend mal adapté à un usa...

On-Line Analytical Processing (OLAP) is a trend in database technology, based on the multidimensional view of data. The aim of this paper is twofold: (a) to list general problems and solutions applicable to the design of any OLAP system and (b) to present the specific design decisions that we made for a prototype under development at NTUA, which we call ERATOSTHENES. The paper addresses require...

Online analytical processing (OLAP) as a modern business intelligence (BI) concept provides support for representing vast amounts of data for supporting management’s decisions. Though, there is no inherent support for the representation of causal structures which could provide a foundation for advanced analysis like what-if or scenario techniques. System Dynamics (SD) is an approach with a long...

A context-aware system is a system that uses context to provide relevant information or services to its users. While there has been a variety of context middleware infrastructures and context-aware applications, little work has been done in integrating context into database management systems. In this paper, we consider a preference system that facilitates context-aware OLAP queries, that is OL...

This paper introduces a visual method in order to explore a document collection. In this approach, a domain is represented under the form of a set of concepts hierarchies that structures the domain knowledge. Users express their points of interest through these hierarchies. One key points of the approach is the use of a data cube representation (which can be found in OLAP systems). Each concept...

OLAP queries (i.e. group-by or cube-by queries with aggregation) have proven to be valuable for data analysis and exploration. Many decision support applications need very complex OLAP queries, requiring a fine degree of control over both the group definition and the aggregates that are computed. For example, suppose that the user has access to a data cube whose measure attribute is Sum(Sales)....

Web usage mining is the application of data mining techniques to discover usage patterns and behaviors from web data (clickstream, purchase information, customer information etc) in order to understand and serve e-commerce customers better and improve the online business. In this paper we present a general Data Warehouse/OLAP framework for web usage mining and business intelligence reporting. W...