Traditional spatial queries return, for a given query object q, all database objects that satisfy a given predicate, such as epsilon range and k-nearest neighbors. This paper defines and studies inverse spatial queries, which, given a subset of database objects Q and a query predicate, return all objects which, if used as query objects with the predicate, contain Q in their result. We first sho...

Foundations A cache is a hardware unit that speeds up access to data. Several cache units may be present at various levels of the memory hierarchy, depending on the processor architecture. For example, a processor may have a small but fast Level-1 (L1) cache for data, and another L1 cache for instructions. The same processor may have a larger but slower L2 cache storing both data and instructio...

The user of a Geographical Information System is not limited to conventional spatial selections and joins, but may also pose more complicated and descriptive queries. In this paper we focus on the efficient processing and optimization of complex spatial queries that involve combinations of spatial selections and joins. Our contribution is manifold; we first provide formulae that accurately esti...

This thesis deals with a special subset of multi-dimensional set of points, called the Skyline. These points are the maxima or minima of the complete set and are of special interest for the field of decision support. Coming from basic algorithms for computing the Skyline we will develop ideas and algorithms for “on-the-fly” or online computation of the Skyline. We will also extend the concept o...

For non-collaborative data sources, both cost estimate-based optimization and quality-driven query processing are difficult to achieve because the sources do not export cost information nor data quality indicators. In this paper, we first propose an expressive query language extension using QML syntax for defining in a flexible way dimensions, metrics of data quality and data source quality. We...

This year, the SICS team decided to concentrate on query processing and on the internal topical structure of the query: we have identified this as one of the major bottlenecks for cross-lingual access systems. Previous years, the SICS team has investigated, among other issues, how to translate compounds. Compound translation is non-trivial due to dependencies between compound elements and has b...

Motivated by cloud security concerns, there is an increasing interest in database systems that can store and support queries over encrypted data. A common architecture for such systems is to use a trusted component such as a cryptographic co-processor for query processing that is used to securely decrypt data and perform computations in plaintext. The trusted component has limited memory, so mo...

In this paper, we have shown how we developed a web app for an improved Google map view by inputing queries and processing it. It’s a typical location based service. As the name suggests the system is intelligent because the KNN query applied to the google map, or any random KNN messages is processed in an intelligent manner, intelligent in the sense that it reduces traffic and maintains high a...

With relations growing larger and queries becoming more complex, parallel query processing is an increasingly attractive option for improving the performance of database systems. The objective of this paper is to examine the various issues encountered in parallel query processing and the techniques available for addressing these issues. The focus of the paper is on the join operation with both ...

For a large-scale distributed query engine, which supports long running queries over federated data sources, it is hard to obtain statistics of data sources, servers and other resources. In addition, the characteristics of data sources and servers are changing at runtime. A traditional distributed query optimizer or centralized adaptive techniques is inadequate in this situation. In this paper,...