It is well-known that the results of analyses of aggregate data, such as those provided as outputs from censuses, are dependent on the size and shape of the zones used to report the data. However, many users of aggregate census data do not consider how far the zones utilised in their analyses capture spatial information about the population sub-groups they are studying. In addition, future data...

We present the TreeScape system which, unlike any other system known to the authors, enables the reuse of pre-computed aggregate query results involving the kinds of irregular dimension hierarchies that occur frequently in practice. The system establishes a foundation for obtaining high-performance query processing while precomputing only few aggregates. It is demonstrated how this reuse of agg...

In relational learning, predictions for an individual are based not only on its own properties but also on the properties of a set of related individuals. Many systems use aggregates to summarize this set. Features thus introduced compare the result of an aggregate function to a threshold. We consider the case where the set to be aggregated is generated by a complex query and present a framewor...

In many practical applications, the need arises to aggregate data of varying dimension. Following from the self-identity property, some recent studies have looked at the stability of aggregation operators in terms of their behavior as the dimensionality is increased from n−1 to n. We use the penalty-based representation of aggregation functions in order to investigate the conditions for weighti...

More than 90% of Malaysian roads are constructed using asphaltic concrete. However, previous investigations of asphaltic concrete have mainly concentrated on the macroscopic properties of the composite materials based on the assumption that the mixtures are homogeneous and isotropic. This paper applies a digital image processing technique to compare the orientations of coarse aggregate particle...

soil characteristics is very important in water erosion processes. the present investigation was conducted in gully lands of ardebil province, iran, to assess the role of soil texture and structure on aggregate stability using wet sieve method. to achieve the study purposes, mean weighted diameter of aggregates was calculated, and its relationships with lime and clay percentages, sodium absorpt...

The sources of aggregate productivity growth are explored using detailed data for four-digit U.S. manufacturing industries during 1958-96 and a decomposition formula which allows to quantify the contribution of structural change. Labor productivity as well as total factor productivity are considered and the aggregation is performed with either value-added or employment shares. It is shown that ...