In one of our previous papers, the idea of deductive data warehouses has been introduced. It was shown how to use Datalog rules to perform Online Analytical Processing (OLAP) analysis on data. In this paper, we show how to use Datalog rules to specify the data warehouse model (data mart) as well as how to add rules that produce aggregate and derived tables that are normally used to speed up the...

This thesis work describes the design and implementation of an aggregate view maintenance mechanism for web applications in the Cloud. Maintaining consistent views and ensuring fault and partition tolerance is generally hard as the CAP theorem postulates that these three properties cannot hold simultaneously. Nevertheless, web application transactions are often characterized by short-lived tran...

The paper is dealing with data cubes, multidimensional data structures built from data warehouse for OLAP purposes. Performing aggregations over cube dimensions and the way they are stored is considered to be a problem worth optimization. A two-tier multilevel list structure for storing cubes has been proposed. Algorithms for tiers’ setup and maintenance when records are loaded into the data wa...

In this paper, situations in which individuals move through a finite set of states according to a continuous-time Markov process are considered. Only aggregate data are available: these consist of the number of individuals in each state at specified observation times. We develop conditional least squares and approximate maximum-likelihood-estimation procedures for time-homogeneous models, and e...

in the future, competitive advantages will be given to organisations that can extract valuable information from massive data and make better decisions. in most cases, this data comes from multiple sources. therefore, the challenge is to aggregate them into a common framework in order to make them meaningful and useful.this paper will first review the most important multi-criteria decision analy...

A fundamental and well-studied problem in computational geometry is range searching, where the goal is to preprocess a set, S, of geometric objects (e.g., points in the plane) so that the subset S ′ ⊆ S that is contained in a query range (e.g., an axes-parallel rectangle) can be reported efficiently. However, in many situations, what is of interest is to generate a more informative “summary” of...

Privacy concerns can be a major barrier to collecting aggregate data from the public. Recent research proposes negative surveys that collect negative data, which is complementary to the true data. This opens a new direction for privacy-aware data collection. However, the existing approach cannot avoid certain errors when applied to many spatial data collection tasks. The errors can make the dat...

Natural language question/answering over RDF data has received widespread attention. Although there have been several studies that have dealt with a small number of aggregate queries, they have many restrictions (i.e., interactive information, controlled question or query template). Thus far, there has been no natural language querying mechanism that can process general aggregate queries over R...

In a data marketplace, producers of data provide query answers to consumers in exchange for payment. A market for data allows capital to flow from data consumers to data producers. This helps to finance the costs of data collection and dissemination, thereby increasing the availability of data throughout society. While nascent data markets exist on the Web, they are currently limited in the pri...