Quality management in MSIS

This paper presents our first incursion in the problem of quality management in Multi-Source Information System (MSIS). We state the problem and experiment with the definition and classification of quality properties. We also experiment with a solution for the problem of quality evaluation in a MSIS considering a few selected properties

Inferring user goals from sets of independent queries in a multidatabase environment

Loosely coupled data integration among networked sources has become so ubiquitous over the recent years that many of the services and applications used daily are actually not monolithic information systems but rather collections of sources tied together. Instead of building centralized and large data sources (i.e., the Extract- Transform-Load method), many organizations and individuals are opting for a virtual database approach. Especially along with the advent of service-oriented architectures, it has become very easy to leave data in its original source and to instead recruit the service provided by that source as needed. This structure is seen in a variety of scenarios such as hybrid web applications (mash-ups), enterprise information integration models, aggregation services and federated information retrieval systems. Furthermore, individual users are often forced to procure and assemble the information they need from sources distributed across a network. © 2010 Springer-Verlag Berlin Heidelberg

Manejo de cambios en la calidad de las fuentes en sistemas de integración de datos

Los Sistemas de Integración de Datos (DIS) integran información desde un conjunto de Fuentes de Datos heterogéneas y autónomas, y proveen dicha información a un conjunto de Vistas de Usuario. Consideramos un sistema donde se toman en cuenta las propiedades de calidad. En las fuentes existen los valores reales de las propiedades de calidad y en el sistema integrado existen los valores requeridos de estas propiedades. En este tipo de sistema, considerando la gran cantidad posible de fuentes y su autonomía, aparece un nuevo problema: los cambios en la calidad de las fuentes. Los valores reales de los elementos de las fuentes pueden cambiar con mucha frecuencia y de forma impredecible. Nos interesan las consecuencias que pueden tener los cambios en la calidad de las fuentes sobre la calidad global del sistema, e incluso sobre el esquema del DIS y la forma de procesar su información. Analizamos estas consecuencias basándonos en las diferentes posibilidades existentes para manejar los cambios en los esquemas de las fuentes en sistemas de este tipo. Además estudiamos dos propiedades en particular; frescura y precisión, y definimos estrategias para el manejo de los cambios en estas propiedades

Data quality maintenance in Data Integration Systems

A Data Integration System (DIS) is an information system that integrates data from a set of heterogeneous and autonomous information sources and provides it to users. Quality in these systems consists of various factors that are measured in data. Some of the usually considered ones are completeness, accuracy, accessibility, freshness, availability. In a DIS, quality factors are associated to the sources, to the extracted and transformed information, and to the information provided by the DIS to the user. At the same time, the user has the possibility of posing quality requirements associated to his data requirements. DIS Quality is considered as better, the nearer it is to the user quality requirements. DIS quality depends on data sources quality, on data transformations and on quality required by users. Therefore, DIS quality is a property that varies in function of the variations of these three other properties. The general goal of this thesis is to provide mechanisms for maintaining DIS quality at a level that satisfies the user quality requirements, minimizing the modifications to the system that are generated by quality changes. The proposal of this thesis allows constructing and maintaining a DIS that is tolerant to quality changes. This means that the DIS is constructed taking into account previsions of quality behavior, such that if changes occur according to these previsions the system is not affected at all by them. These previsions are provided by models of quality behavior of DIS data, which must be maintained up to date. With this strategy, the DIS is affected only when quality behavior models change, instead of being affected each time there is a quality variation in the system. The thesis has a probabilistic approach, which allows modeling the behavior of the quality factors at the sources and at the DIS, allows the users to state flexible quality requirements (using probabilities), and provides tools, such as certainty, mathematical expectation, etc., that help to decide which quality changes are relevant to the DIS quality. The probabilistic models are monitored in order to detect source quality changes, strategy that allows detecting changes on quality behavior and not only punctual quality changes. We propose to monitor also other DIS properties that affect its quality, and for each of these changes decide if they affect the behavior of DIS quality, taking into account DIS quality models. Finally, the probabilistic approach is also applied at the moment of determining actions to take in order to improve DIS quality. For the interpretation of DIS situation we propose to use statistics, which include, in particular, the history of the quality models

Machine Learning

Machine Learning can be defined in various ways related to a scientific domain concerned with the design and development of theoretical and implementation tools that allow building systems with some Human Like intelligent behavior. Machine learning addresses more specifically the ability to improve automatically through experience

Datenqualität in Sensordatenströmen

Die stetige Entwicklung intelligenter Sensorsysteme erlaubt die Automatisierung und Verbesserung komplexer Prozess- und Geschäftsentscheidungen in vielfältigen Anwendungsszenarien. Sensoren können zum Beispiel zur Bestimmung optimaler Wartungstermine oder zur Steuerung von Produktionslinien genutzt werden. Ein grundlegendes Problem bereitet dabei die Sensordatenqualität, die durch Umwelteinflüsse und Sensorausfälle beschränkt wird. Ziel der vorliegenden Arbeit ist die Entwicklung eines Datenqualitätsmodells, das Anwendungen und Datenkonsumenten Qualitätsinformationen für eine umfassende Bewertung unsicherer Sensordaten zur Verfügung stellt. Neben Datenstrukturen zur effizienten Datenqualitätsverwaltung in Datenströmen und Datenbanken wird eine umfassende Datenqualitätsalgebra zur Berechnung der Qualität von Datenverarbeitungsergebnissen vorgestellt. Darüber hinaus werden Methoden zur Datenqualitätsverbesserung entwickelt, die speziell auf die Anforderungen der Sensordatenverarbeitung angepasst sind. Die Arbeit wird durch Ansätze zur nutzerfreundlichen Datenqualitätsanfrage und -visualisierung vervollständigt

Designing Cross-Company Business Intelligence Networks

Business Intelligence (BI) ist der allgemein akzeptierte Begriff für Methoden, Konzepte und Werkzeuge zur Sammlung, Aufbereitung, Speicherung, Verteilung und Analyse von Daten für Management- und Geschäftsentscheidungen. Obwohl unternehmensübergreifende Kooperation in den vergangenen Jahrzehnten stets an Einfluss gewonnen hat, existieren nur wenige Forschungsergebnisse im Bereich unternehmensübergreifender BI. Die vorliegende Arbeit stellt eine Arbeitsdefinition des Begriffs Cross-Company BI (CCBI) vor und grenzt diesen von gemeinschaftlicher Entscheidungsfindung ab. Auf Basis eines Referenzmodells, das existierende Arbeiten und Ansätze verwandter Forschungsbereiche berücksichtigt, werden umfangreiche Simulationen und Parametertests unternehmensübergreifender BI-Netzwerke durchgeführt. Es wird gezeigt, dass eine Peer-To-Peer-basierte Gestaltung der Netzwerke leistungsfähig und kompetitiv zu existierenden zentral-fokussierten Ansätzen ist. Zur Quantifizierung der Beobachtungen werden Messgrößen geprüft, die sich aus existierenden Konzepten zur Schemaüberführung multidimensionaler Daten sowie Überlegungen zur Daten- und Informationsqualität ableiten oder entwickeln lassen.Business Intelligence (BI) is a well-established term for methods, concepts and tools to retrieve, store, deliver and analyze data for management and business purposes. Although collaboration across company borders has substantially increased over the past decades, little research has been conducted specifically on Cross-Company BI (CCBI). In this thesis, a working definition and distinction from general collaborative decision making is proposed. Based on a reference model that takes existing research and related approaches of adjacent fields into account a peer-to-peer network design is created. With an extensive simulation and parameter testing it is shown that the design proves valuable and competitive to centralized approaches and that obtaining a critical mass of participants leads to improved usefulness of the network. To quantify the observations, appropriate quality measures rigorously derived from respected concepts on data and information quality and multidimensional data models are introduced and validated