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Preparing a data set for analysis is generally the most time consuming task in a data mining project, requiring many complex SQL queries, joining tables, and aggregating columns. Existing SQL aggregations have limitations to prepare data sets because they return one column per aggregated group. In general, a significant manual effort is required to build(More)
Statistical tests represent an important technique used to formulate and validate hypotheses on a dataset. They are particularly useful in the medical domain, where hypotheses link disease with medical measurements, risk factors, and treatment. In this paper, we propose to compute parametric statistical tests treating patient records as elements in a(More)
Previous studies suggested that ERP component contralateral delay activity (CDA) tracks the number of objects containing identity information stored in visual short term memory (VSTM). Later MEG and fMRI studies implied that its neural source lays in superior IPS. However, since the memorized stimuli in previous studies were displayed in distinct spatial(More)
Distributed relational databases are used by different organizations located at multiple sites that work together on common projects. In this article, we focus on distributed relational databases with incomplete and inconsistent content. We propose to measure referential integrity errors in them for integration and interoperability purposes. We propose(More)
Since the early 1990s, On-Line Analytical Processing (OLAP) has been a well studied research topic that has focused on implementation outside the database, either with OLAP servers or entirely within the client computers. Our approach involves the computation and storage of OLAP cubes using User-Defined Functions (UDF) with a database management system.(More)
The exploitation of a low-cost catalyst is desirable for hydrogen generation from electrolysis or photoelectrolysis. In this study we have demonstrated that nickel phosphide (Ni12P5) nanoparticles have efficient and stable catalytic activity for the hydrogen evolution reaction. The catalytic performance of Ni12P5 nanoparticles is favorably comparable to(More)
In On-Line Analytical Processing (OLAP), users explore a database cube with roll-up and drill-down operations in order to find interesting results. Most approaches rely on simple aggregations and value comparisons in order to validate findings. In this work, we propose to combine OLAP dimension lattice traversal and statistical tests to discover significant(More)
Association rules is a technique that can detect patterns within the items of a dataset. The constrained version applies several restrictions that reduces the number of rules and also helps improve performance. On the other hand, OLAP statistical tests is an integration of exploratory On-Line Analytical Processing techniques and statistical tests. It uses a(More)
A federated database consists of several loosely integrated databases, where each database may contain hundreds of tables and thousands of columns,interrelated by complex foreign key relationships. In general, there exists a lot of semistructured data elements outside the database represented by documents (files), created and updated by multiple users and(More)