Download or read book Database Repairs and Consistent Query Answering written by Leopoldo Bertossi and published by Springer Nature. This book was released on 2022-05-31 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: Integrity constraints are semantic conditions that a database should satisfy in order to be an appropriate model of external reality. In practice, and for many reasons, a database may not satisfy those integrity constraints, and for that reason it is said to be inconsistent. However, and most likely, a large portion of the database is still semantically correct, in a sense that has to be made precise. After having provided a formal characterization of consistent data in an inconsistent database, the natural problem emerges of extracting that semantically correct data, as query answers. The consistent data in an inconsistent database is usually characterized as the data that persists across all the database instances that are consistent and minimally differ from the inconsistent instance. Those are the so-called repairs of the database. In particular, the consistent answers to a query posed to the inconsistent database are those answers that can be simultaneously obtained from all the database repairs. As expected, the notion of repair requires an adequate notion of distance that allows for the comparison of databases with respect to how much they differ from the inconsistent instance. On this basis, the minimality condition on repairs can be properly formulated. In this monograph we present and discuss these fundamental concepts, different repair semantics, algorithms for computing consistent answers to queries, and also complexity-theoretic results related to the computation of repairs and doing consistent query answering. Table of Contents: Introduction / The Notions of Repair and Consistent Answer / Tractable CQA and Query Rewriting / Logically Specifying Repairs / Decision Problems in CQA: Complexity and Algorithms / Repairs and Data Cleaning

Download or read book Database Repairing and Consistent Query Answering written by Leopoldo Bertossi and published by Morgan & Claypool Publishers. This book was released on 2011 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Integrity constraints are semantic conditions that a database should satisfy in order to be an appropriate model of external reality. In practice, and for many reasons, a database may not satisfy those integrity constraints, and for that reason it is said to be inconsistent. However, and most likely, a large portion of the database is still semantically correct, in a sense that has to be made precise. After having provided a formal characterization of consistent data in an inconsistent database, the natural problem emerges of extracting that semantically correct data, as query answers. The consistent data in an inconsistent database is usually characterized as the data that persists across all the database instances that are consistent and minimally differ from the inconsistent instance. Those are the so-called repairs of the database. In particular, the consistent answers to a query posed to the inconsistent database are those answers that can be simultaneously obtained from all the database repairs. As expected, the notion of repair requires an adequate notion of distance that allows for the comparison of databases with respect to how much they differ from the inconsistent instance. On this basis, the minimality condition on repairs can be properly formulated. In this monograph we present and discuss these fundamental concepts, different repair semantics, algorithms for computing consistent answers to queries, and also complexity-theoretic results related to the computation of repairs and doing consistent query answering. Table of Contents: Introduction / The Notions of Repair and Consistent Answer / Tractable CQA and Query Rewriting / Logically Specifying Repairs / Decision Problems in CQA: Complexity and Algorithms / Repairs and Data Cleaning

Download or read book Data Cleaning written by Ihab F. Ilyas and published by Morgan & Claypool. This book was released on 2019-06-18 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an overview of the end-to-end data cleaning process. Data quality is one of the most important problems in data management, since dirty data often leads to inaccurate data analytics results and incorrect business decisions. Poor data across businesses and the U.S. government are reported to cost trillions of dollars a year. Multiple surveys show that dirty data is the most common barrier faced by data scientists. Not surprisingly, developing effective and efficient data cleaning solutions is challenging and is rife with deep theoretical and engineering problems. This book is about data cleaning, which is used to refer to all kinds of tasks and activities to detect and repair errors in the data. Rather than focus on a particular data cleaning task, this book describes various error detection and repair methods, and attempts to anchor these proposals with multiple taxonomies and views. Specifically, it covers four of the most common and important data cleaning tasks, namely, outlier detection, data transformation, error repair (including imputing missing values), and data deduplication. Furthermore, due to the increasing popularity and applicability of machine learning techniques, it includes a chapter that specifically explores how machine learning techniques are used for data cleaning, and how data cleaning is used to improve machine learning models. This book is intended to serve as a useful reference for researchers and practitioners who are interested in the area of data quality and data cleaning. It can also be used as a textbook for a graduate course. Although we aim at covering state-of-the-art algorithms and techniques, we recognize that data cleaning is still an active field of research and therefore provide future directions of research whenever appropriate.

Download or read book Flexible Query Answering Systems written by Henrik Legind Larsen and published by Springer Science & Business Media. This book was released on 2006-05-30 with total page 730 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceeding of the 7th International Conference on Flexible Query Answering Systems, FQAS 2006, held in Milan, Italy in June 2006. The 60 revised full papers presented were carefully reviewed and selected from numerous submissions. The papers are organized in topical sections on flexibility in database management and quering, vagueness and uncertainty in XML quering and retrieval, information retrieval and filtering, multimedia information access, user modeling and personalization, knowledge and data extraction, intelligent information extraction from text, and knowledge representation and reasoning.

Download or read book Flexible Query Answering Systems written by Troels Andreasen and published by Springer Nature. This book was released on 2021-09-15 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 14th International Conference on Flexible Query Answering Systems, FQAS 2021, held virtually and in Bratislava, Slovakia, in September 2021. The 16 full papers and 1 perspective papers presented were carefully reviewed and selected from 17 submissions. They are organized in the following topical sections: model-based flexible query answering approaches and data-driven approaches.

Download or read book Trends in Cleaning Relational Data written by Ihab F Ilyas and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Theory and Applications of Satisfiability Testing SAT 2016 written by Nadia Creignou and published by Springer. This book was released on 2016-06-10 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 19th International Conference on Theory and Applications of Satisfiability Testing, SAT 2016, held in Bordeaux, France, in July 2016. The 31 regular papers, 5 tool papers presented together with 3 invited talks were carefully reviewed and selected from 70 submissions. The papers address different aspects of SAT, including complexity, satisfiability solving, satisfiability applications, satisfiability modulop theory, beyond SAT, quantified Boolean formula, and dependency QBF.

Download or read book Repairing and Querying Databases under Aggregate Constraints written by Sergio Flesca and published by Springer Science & Business Media. This book was released on 2011-10-20 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research has deeply investigated several issues related to the use of integrity constraints on relational databases. In particular, a great deal of attention has been devoted to the problem of extracting "reliable" information from databases containing pieces of information inconsistent with regard to some integrity constraints. In this manuscript, the problem of extracting consistent information from relational databases violating integrity constraints on numerical data is addressed. Aggregate constraints defined as linear inequalities on aggregate-sum queries on input data are considered. The notion of repair as consistent set of updates at attribute-value level is exploited, and the characterization of several data-complexity issues related to repairing data and computing consistent query answers is provided. Moreover, a method for computing “reasonable” repairs of inconsistent numerical databases is introduced, for a restricted but expressive class of aggregate constraints. An extension of this method for dealing with the data repairing problem in the presence of weak aggregate constraints which are expected to be satisfied, but not required to, is presented. Furthermore, a technique for computing consistent answers of aggregate queries in the presence of a wide form of aggregate constraints is provided. Finally, extensions of the framework as well as several open problems are discussed.

Download or read book Elements of Finite Model Theory written by Leonid Libkin and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emphasizes the computer science aspects of the subject. Details applications in databases, complexity theory, and formal languages, as well as other branches of computer science.

Download or read book Complex Pattern Mining written by Annalisa Appice and published by Springer Nature. This book was released on 2020-01-14 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses the challenges facing current research in knowledge discovery and data mining posed by the huge volumes of complex data now gathered in various real-world applications (e.g., business process monitoring, cybersecurity, medicine, language processing, and remote sensing). The book consists of 14 chapters covering the latest research by the authors and the research centers they represent. It illustrates techniques and algorithms that have recently been developed to preserve the richness of the data and allow us to efficiently and effectively identify the complex information it contains. Presenting the latest developments in complex pattern mining, this book is a valuable reference resource for data science researchers and professionals in academia and industry.

Download or read book Flexible Query Answering Systems written by Henrik L. Larsen and published by Springer Science & Business Media. This book was released on 2012-08-27 with total page 617 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume constitutes the proceedings of the Fourth International Conference on Flexible Query Answering Systems, FQAS'2000, held in Warsaw, Poland on October 25 - 28, 2000. The FQAS conference has been the premier conference focusing on one of key issues that the information society faces, namely that of providing easy, flexible, intuitive access to information for everybody. In targeting this issue, the conference draws on several research areas, such as databases, querying, information retrieval, knowledge representation, soft computing, cyberspace, multimedia systems, human-computer interaction, etc. FQAS'2000 has been preceded by the extremely successful FQAS'94, FQAS'96 and FQAS'98 conferences all held in Roskilde, Denmark. The present conference provides a unique opportunity for researchers, developers and practitioners to explore new ideas and approaches in a multidisciplinary forum. As a metaphor for flexible query answering we may consider a human intermediary who has expertise in the topic of the query, and is experienced in identifying the user's information needs and answering the needs from the available information resources. The use of knowledge on relevant contexts, available information resources, etc. , enables the expert to respond rather precisely to the needs, though the query, per se, may be imprecise, incomplete, etc. Thus, a key issue for flexible query answering system is to obtain, maintain, represent, and utilize such knowledge. This comprises domain knowledge and metaknowledge, its representation and organization in ontologies, terminologies, etc.

Download or read book Theory and Applications of Satisfiability Testing SAT 2019 written by Mikoláš Janota and published by Springer. This book was released on 2019-06-28 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 22nd International Conference on Theory and Applications of Satisfiability Testing, SAT 2019, held in Lisbon, Portugal, UK, in July 2019. The 19 revised full papers presented together with 7 short papers were carefully reviewed and selected from 64 submissions. The papers address different aspects of SAT interpreted in a broad sense, including (but not restricted to) theoretical advances (such as exact algorithms, proof complexity, and other complexity issues), practical search algorithms, knowledge compilation, implementation-level details of SAT solvers and SAT-based systems, problem encodings and reformulations, applications (including both novel application domains and improvements to existing approaches), as well as case studies and reports on findings based on rigorous experimentation.

Download or read book Scalable Uncertainty Management written by Eyke Hüllermeier and published by Springer. This book was released on 2012-09-11 with total page 662 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 6th International Conference on Scalable Uncertainty Management, SUM 2012, held in Marburg, Germany, in September 2012. The 41 revised full papers and 13 revised short papers were carefully reviewed and selected from 75 submissions. The papers cover topics in all areas of managing and reasoning with substantial and complex kinds of uncertain, incomplete or inconsistent information including applications in decision support systems, machine learning, negotiation technologies, semantic web applications, search engines, ontology systems, information retrieval, natural language processing, information extraction, image recognition, vision systems, data and text mining, and the consideration of issues such as provenance, trust, heterogeneity, and complexity of data and knowledge.

Download or read book Database Reliability Engineering written by Laine Campbell and published by "O'Reilly Media, Inc.". This book was released on 2017-10-26 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: The infrastructure-as-code revolution in IT is also affecting database administration. With this practical book, developers, system administrators, and junior to mid-level DBAs will learn how the modern practice of site reliability engineering applies to the craft of database architecture and operations. Authors Laine Campbell and Charity Majors provide a framework for professionals looking to join the ranks of today’s database reliability engineers (DBRE). You’ll begin by exploring core operational concepts that DBREs need to master. Then you’ll examine a wide range of database persistence options, including how to implement key technologies to provide resilient, scalable, and performant data storage and retrieval. With a firm foundation in database reliability engineering, you’ll be ready to dive into the architecture and operations of any modern database. This book covers: Service-level requirements and risk management Building and evolving an architecture for operational visibility Infrastructure engineering and infrastructure management How to facilitate the release management process Data storage, indexing, and replication Identifying datastore characteristics and best use cases Datastore architectural components and data-driven architectures

Download or read book Database Theory ICDT 2003 written by Diego Calvanese and published by Springer. This book was released on 2003-07-01 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 9th International Conference on Database Theory, ICDT 2002, held in Siena, Italy in January 2002. The 26 revised full papers presented together with 3 invited articles were carefully reviewed and selected from 92 submissions. The papers are organized in topical sections on reasoning about XML schemas and queries, aggregate queries, query evaluation, query rewriting and reformulation, semistructured versus structured data, query containment, consistency and incompleteness, and data structures.

Download or read book Transactions on Large Scale Data and Knowledge Centered Systems LIV written by Abdelkader Hameurlain and published by Springer Nature. This book was released on 2023-10-23 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: The LNCS journal Transactions on Large-scale Data and Knowledge-centered Systems focuses on data management, knowledge discovery, and knowledge processing, which are core and hot topics in computer science. Since the 1990s, the Internet has become the main driving force behind application development in all domains. An increase in the demand for resource sharing across different sites connected through networks has led to an evolution of data- and knowledge-management systems from centralized systems to decentralized systems enabling large-scale distributed applications providing high scalability. This, the 54th issue of Transactions on Large-Scale Data and Knowledge-Centered Systems, contains three fully revised and extended papers and two additional extended keynotes selected from the 38th conference on Data Management - Principles, Technologies and Applications, BDA 2022. The topics cover a wide range of timely data management research topics on temporal graph management, tensor-based data mining, time-series prediction, healthcare analytics over knowledge graphs, and explanation of database query answers.

Download or read book Flexible Query Answering Systems written by Alfredo Cuzzocrea and published by Springer Nature. This book was released on 2019-09-11 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 13th International Conference on Flexible Query Answering Systems, FQAS 2019, held in Amantea, Italy, in July 2019. The 27 full papers and 10 short papers presented were carefully reviewed and selected from 43 submissions. The papers present emerging research trends with a special focus on flexible querying and analytics for smart cities and smart societies in the age of big data. They are organized in the following topical sections: flexible database management and querying; ontologies and knowledge bases; social networks and social media; argumentation-based query answering; data mining and knowledge discovery; advanced flexible query answering methodologies and techniques; flexible query answering methods and techniques; flexible intelligent information-oriented and network-oriented approaches; big data veracity and soft computing; flexibility in tools; and systems and miscellanea.