Data integration is the problem of combining data residing at different sources, and providing the user with a unified view of these data. The problem of designing data integration systems is important in current real world applications, and is characterized by a number of issues that are interesting from a theoretical point of view. This document presents on overview of the material to be presented in a tutorial on data integration. The tutorial is focused on some of the theoretical issues that are relevant for data integration. Special attention will be devoted to the following aspects: modeling a data integration application, processing queries in data integration, dealing with inconsistent data sources, and reasoning on queries.

/pdf/data-integration-a-theoretical-perspective-58aesjvhuk.pdf

Data integration: a theoretical perspective

Personalized web services strive to adapt their services (advertisements, news articles, etc.) to individual users by making use of both content and user information. Despite a few recent advances, this problem remains challenging for at least two reasons. First, web service is featured with dynamically changing pools of content, rendering traditional collaborative filtering methods inapplicable. Second, the scale of most web services of practical interest calls for solutions that are both fast in learning and computation.In this work, we model personalized recommendation of news articles as a contextual bandit problem, a principled approach in which a learning algorithm sequentially selects articles to serve users based on contextual information about the users and articles, while simultaneously adapting its article-selection strategy based on user-click feedback to maximize total user clicks.The contributions of this work are three-fold. First, we propose a new, general contextual bandit algorithm that is computationally efficient and well motivated from learning theory. Second, we argue that any bandit algorithm can be reliably evaluated offline using previously recorded random traffic. Finally, using this offline evaluation method, we successfully applied our new algorithm to a Yahoo! Front Page Today Module dataset containing over 33 million events. Results showed a 12.5% click lift compared to a standard context-free bandit algorithm, and the advantage becomes even greater when data gets more scarce.

/pdf/a-contextual-bandit-approach-to-personalized-news-article-13tixfy0pk.pdf

A contextual-bandit approach to personalized news article recommendation

This introduction presents the main motivations for the development of Description Logics (DLs) as a formalism for representing knowledge, as well as some important basic notions underlying all systems that have been created in the DL tradition. In addition, we provide the reader with an overview of the entire book and some guidelines for reading it. We first address the relationship between Description Logics and earlier semantic network and frame systems, which represent the original heritage of the field. We delve into some of the key problems encountered with the older efforts. Subsequently, we introduce the basic features of DL languages and related reasoning techniques. DL languages are then viewed as the core of knowledge representation systems, considering both the structure of a DL knowledge base and its associated reasoning services. The development of some implemented knowledge representation systems based on Description Logics and the first applications built with such systems are then reviewed. Finally, we address the relationship of Description Logics to other fields of Computer Science.We also discuss some extensions of the basic representation language machinery; these include features proposed for incorporation in the formalism that originally arose in implemented systems, and features proposed to cope with the needs of certain application domains.

https://assets.cambridge.org/97805218/76254/frontmatter/9780521876254_frontmatter.pdf

The Description Logic Handbook

We classify data quality problems that are addressed by data cleaning and provide an overview of the main solution approaches. Data cleaning is especially required when integrating heterogeneous data sources and should be addressed together with schema-related data transformations. In data warehouses, data cleaning is a major part of the so-called ETL process. We also discuss current tool support for data cleaning.

/pdf/data-cleaning-problems-and-current-approaches-2c16prrxgi.pdf

Data Cleaning: Problems and Current Approaches.

The problem of answering queries using views is to find efficient methods of answering a query using a set of previously defined materialized views over the database, rather than accessing the database relations. The problem has recently received significant attention because of its relevance to a wide variety of data management problems. In query optimization, finding a rewriting of a query using a set of materialized views can yield a more efficient query execution plan. To support the separation of the logical and physical views of data, a storage schema can be described using views over the logical schema. As a result, finding a query execution plan that accesses the storage amounts to solving the problem of answering queries using views. Finally, the problem arises in data integration systems, where data sources can be described as precomputed views over a mediated schema. This article surveys the state of the art on the problem of answering queries using views, and synthesizes the disparate works into a coherent framework. We describe the different applications of the problem, the algorithms proposed to solve it and the relevant theoretical results.

/pdf/answering-queries-using-views-a-survey-4aug5icc6d.pdf

Answering queries using views: A survey

Most existing work in agent programming assumes an execution model where an agent has a knowledge base (KB) about the current state of the world, and makes decisions about what to do in terms of what is entailed or consistent with this KB. Planning then involves looking ahead and gauging what would be consistent or entailed at various stages by possible future KBs. We show that in the presence of sensing, such a model does not always work properly, and propose an alternative that does. We then discuss how this affects agent programming language design/semantics.

/pdf/on-ability-to-autonomously-execute-agent-programs-with-369loprl9g.pdf

On Ability to Autonomously Execute Agent Programs with Sensing

We study the data complexity of answering conjunctive queries over Description Logic knowledge bases constituted by a TBox and an ABox. In particular, we are interested in characterizing the FO-rewritability and the polynomial tractability boundaries of conjunctive query answering, depending on the expressive power of the DL used to express the knowledge base. What emerges from our complexity analysis is that the Description Logics of the DL-Lite family are essentially the maximal logics allowing for conjunctive query answering through standard database technology.

Data complexity of query answering in description logics

The tutorial aims at providing a deep comprehension of the Web service composition problem and automated techniques to tackle it. Web service composition is currently one the most hyped and addressed issue in the service oriented computing. Starting from an analysis of current technologies and standards for Web service composition, the tutorial will lead the attendees to consider formal models at the base of current proposals, and techniques that can be fruitfully considered to address automatic composition synthesis in each of them. More in detail, attendees will consider: (i) basic technologies and standards for Web service invocation and description (SOAP, UDDI, WSDL,...); (ii) advanced technologies and standards for orchestration and inter-organizational process enactment, in particular WS-BPEL and WS-CDL; (iii) models for Web service composition; (iv) formal tools for both data-centric and process-centric synthesis, including query reformulation a'la data integration, transition-systems based formalisms, trace-based formalisms, logics of programs and processes. In particular, we will show how these formal tools can be applied for automatic Web service composition; (v) current state-of-the-art research results in automatic service composition, drawing a comparison and defining a unifying framework

Tutorial 3: Automatic Web Service Composition

EU STREP project FP6-2005-IST-5-034749 – WORKPAD Deliverable D3.2 (WP3) – This document presents the different algorithms, methods and techniques of the WORKPAD Front-end. Such contributions represent the original scientific contribution of WP3; their architectural and technical design and realization are presented in D3.1 (v1 and v2), whereas the actual software is presented in D3.3. Each chapter is devoted to a specific component of the front-end which presents novel techniques. Copyright c © 2008 The WORKPAD Consortium Document Identifier WORKPAD/2008/D3.2/v1.0 Project FP6-2005-IST-5-034749 Version v1.0 Due date May 30, 2008 Release date June 10, 2008 State FINAL Distribution PUBLIC

G. De Giacomo

Papers

On Ability to Autonomously Execute Agent Programs with Sensing

Data complexity of query answering in description logics

Tutorial 3: Automatic Web Service Composition

D3.2 - Basic Algorithms, Methods and Techniques for the Front-End