Skyline query processing has been investigated extensively in recent years, mostly for only one query reference point. An example of a single-source skyline query is to find hotels which are cheap and close to the beach (an absolute query), or close to a user-given location (a relatively query). A multi-source skyline query considers several query points at the same time In this paper, we consi...

In recent years, the skyline query paradigm has been established as a reliable method for database query personalization. While early efficiency problems have been solved by sophisticated algorithms and advanced indexing, new challenges in skyline retrieval effectiveness continuously arise. Especially, the rise of the Semantic Web and linked open data leads to personalization issues where skyli...

The skyline queries has received considerable attention from the database community, due to its importance in many applications including multicriteria decision making, preference answering, and so forth. Data collected from different sources in distributed locations exhibit a kind of uncertainty. A skyline query retrieves the set of nondominated data points in a multi-dimensional dataset. For ...

Traditionally, skyline and ranking queries have been treated separately as alternative ways of discovering interesting data in potentially large datasets. While ranking queries adopt a specific scoring function to rank tuples, skyline queries return the set of non-dominated tuples and are independent of attribute scales and scoring functions. Ranking queries are thus less general, but usually c...

Skyline queries are generally considered as a promising technique for mitigating the challenges posed by the ever growing amount of available information. However, despite nearly a decade of research, the application of the Skyline paradigm in real-world information systems still failed to succeed. This fact was mainly attributed to two major problems: the poor performance of the employed algor...

Relaxation skyline queries have been proposed, in the relational context, as a solution to the so-called empty answer problem. Given a query composed of selection and join operations, a relaxation skyline query relies on the usage of a relaxation function (usually, a numeric function) to quantify the distance of each tuple (pair of tuples in case of join) from the specified conditions and uses ...

Given a query tuple q, the dynamic skyline query retrieves the tuples that are not dynamically dominated by any other in the data set with respect to q. A tuple dynamically dominates another, w.r.t. q, if it has closer to q’s values in all attributes, and has strictly closer to q’s value in at least one. The dynamic skyline query can be treated as a standard skyline query, subject to the transf...

The skyline operator is important for multicriteria decision making applications. Although many recent studies developed efficient methods to compute skyline objects in a specific space, the fundamental problem on the semantics of skylines remains open: Why and in which subspaces is (or is not) an object in the skyline? Practically, users may also be interested in the skylines in any subspaces....