Optimal top-k query evaluation for weighted business processes

Abstract

A Business Process (BP for short) consists of a set of activities that achieve some business goal when combined in a flow. Among all the (maybe infinitely many) possible execution flows of a BP, analysts are often interested in identifying flows that are "most important", according to some weight metric. This paper studies the following problem: given a specification of such a BP, a weighting function over BP execution flows, a query, and a number k, identify the k flows with the highest weight among those satisfying the query. We provide here, for the first time, a provably optimal algorithm for identifying the top-k weighted flows of a given BP, and use it for efficient top-k query evaluation.

Goal-oriented web-site navigation for on-line shoppers

“…To address these needs, ShopIT uses a novel, dynamic and adaptive top-k query evaluation algorithm. Our algorithm can be formally proved to be optimal [6] and our experiments show that it is very efficient in practice.…”

“…Then it greedily analyzes the refined representation to obtain the best-ranked flows. (The reader is referred to [6] for details.) The choices made by the user throughout the navigation are modeled as additional constraints/relaxations to the original query, and an efficient adaptive evaluation technique is employed to update the query result.…”

“…The importance of customizable recommendation systems was recently recognized in [9], where such a flexible system was introduced in the context of relational data. The (possibly recursive) semi-structured shape of Web-applications introduces unique challenges for top-k computation, that are not found in a relational environment [6]. We stress that while the demonstration scenario considers a specific example of an on-line computer store, the underlying recommendation system presented here is generic, and an adaptation to other settings will only require the replacement of our Front-End that retrieves application and products data from Yahoo!…”

On models and query languages for probabilistic processes

“…We (informally) depict in this section the model of probabilistic Business Processes (BPs), and a query language over such processes, originally defined and used in [5,16,17,18]. Additional process models and their connection to this model are discussed in Section 4.…”

“…Many models for specifying and querying such processes exist in the literature; a main goal of research in this area is to design models that are expressive enough to capture real-life processes and analysis tasks, but at the same time allow for efficient query evaluation. We depict the model established in [13,16,17,18], and claim that it achieves a good balance between expressivity and query evaluation complexity. We compare and contrast the model with other common models for probabilistic processes, highlighting the different choices made in models design and their effect on expressivity and incurred complexity.…”