Towards a management framework for data semantic conflicts : a financial applications perspective

Includes bibliographical references (p. 23-25).Raphael Yahalom and Stuart E. Madnick

Implementing a universal relation interface using access scripts with binding patterns

We propose the use of the universal relation as a user interface to provide transparent access to a network of distributed, heterogeneous, and autonomous information sources. We implement this interface in two layers. The lower layer consists of access scripts, which encapsulate knowledge about information sources and are capable of answering basic queries. The upper layer uses combinations of these scripts to answer user queries phrased in terms of a universal relation. Access scripts know how to obtain information either directly from sources or from service providers (mediators, traders, and the like). They present this information in relational form, but with an inherent direction, in the sense that whenever values for a fixed subset of attributes of the relation are given, the access script will deliver values for the rest of the attributes in the relation. In this paper, we address the problem of defining the semantics of a user query posed against the universal relation and of finding a sequence of access script invocations that gathers the information requested in the query

JUpdate: A JSON Update Language

Although JSON documents are being used in several emerging applications (e.g., Big Data applications, IoT, mobile computing, smart cities, and online social networks), there is no consensual or standard language for updating JSON documents (i.e., creating, deleting or changing such documents, where changing means inserting, deleting, replacing, copying, moving, etc., portions of data in such documents). To fill this gap, we propose in this paper an SQL-like language, named JUpdate, for updating JSON documents. JUpdate is based on a set of six primitive update operations, which is proven complete and minimal, and it provides a set of fourteen user-friendly high-level operations with a well-founded semantics defined on the basis of the primitive update operations

Verteilung und Integration von Informationen im Verkehrsbereich

Verteilung und Mobilität spielen in der Verkehrstelematik eine große Rolle. Die verwendeten Datenquellen sind im Allgemeinen heterogen und von unterschiedlicher Qualität. Im Rahmen des Verbundprojektes OVID der Universität Karlsruhe (TH) bot das Institut für Programmstrukturen und Datenorganisation (IPD) im Sommersemester 2004 ein Seminar mit dem Titel "Verteilung und Integration von Informationen im Verkehrsbereich" an. In diesem Seminar wurden Fragestellungen untersucht, die sich mit den Anforderungen und existierenden Techniken für hochgradige Verteilung und Mobilität von Datenquellen im Verkehrsbereich beschäftigten. Die dabei erzielten Ergebnisse werden in diesem Bericht vorgestellt

Ontological View-driven Semantic Integration in Open Environments

In an open computing environment, such as the World Wide Web or an enterprise Intranet, various information systems are expected to work together to support information exchange, processing, and integration. However, information systems are usually built by different people, at different times, to fulfil different requirements and goals. Consequently, in the absence of an architectural framework for information integration geared toward semantic integration, there are widely varying viewpoints and assumptions regarding what is essentially the same subject. Therefore, communication among the components supporting various applications is not possible without at least some translation. This problem, however, is much more than a simple agreement on tags or mappings between roughly equivalent sets of tags in related standards. Industry-wide initiatives and academic studies have shown that complex representation issues can arise. To deal with these issues, a deep understanding and appropriate treatment of semantic integration is needed. Ontology is an important and widely accepted approach for semantic integration. However, usually there are no explicit ontologies with information systems. Rather, the associated semantics are implied within the supporting information model. It reflects a specific view of the conceptualization that is implicitly defining an ontological view. This research proposes to adopt ontological views to facilitate semantic integration for information systems in open environments. It proposes a theoretical foundation of ontological views, practical assumptions, and related solutions for research issues. The proposed solutions mainly focus on three aspects: the architecture of a semantic integration enabled environment, ontological view modeling and representation, and semantic equivalence relationship discovery. The solutions are applied to the collaborative intelligence project for the collaborative promotion / advertisement domain. Various quality aspects of the solutions are evaluated and future directions of the research are discussed

Ontology-Based Information Sharing in Weakly Structured Environments

Harmelen, F.A.H. van [Promotor]Herzog, O. [Copromotor

Algebraic Query Optimization in Database Systems (Algebraische Anfrageoptimierung in Datenbanksystemen)

The thesis investigates different problem classes in algebraic query optimization. For the problem of computing optimal left-deep processing trees with cross products for chain queries and ASI cost functions we present two efficient algorithms. Although, in practice both algorithms yield identical results we have not been able to prove this. For the case of acyclic query graphs, left-deep processing trees, expensive selection and join predicates and ASI cost functions we describe a polynomial time algorithm which is based on a job sequencing algorithm. The algorithm assumes that the set of expensive selections that can be applied directly to the base relations can be guessed. The cheapest plans can be found within the search space of bushy processing trees with cross products. We prove that the problem is NP-hard in this case. The rest of the thesis deals with the general problem of computing optimal bushy processing trees for arbitrary query graphs and expensive selection and join predicates. For this problem we present three efficient dynamic programming algorithms. Our algorithms can handle different join algorithms, split conjunctive predicates, and exploit structural information from the join graph to speed up computation. The time and space complexities of the algorithms are analyzed carefully and efficient implementations based on bitvector arithmetic are presented

Über die Pragmatik der Graphischen Modellierung

Graphical models help to understand complex systems. However, with the user interaction paradigms established today, activities such as creating, maintaining or browsing graphical models can be very tedious. This thesis presents an approach to enhance productivity by focusing on the pragmatics of model-based design. The contribution includes an interpretation of the notion of pragmatics, orthogonal to syntax and semantics in Model-Driven Engineering (MDE). A proposal on pragmatics-aware modeling is given, employing sophisticated automated layout algorithms to close the gap between MDE and graph drawing theory. Thus, a view management logic presents customized views on models. These concepts get illustrated with the open source Kiel Integrated Environment for Layout Eclipse Rich Client (KIELER) with multiple applications including editing and simulation and shows how view management helps to tame complexity