In this paper, we discuss the application of concept of data quality to big data by highlighting how much complex is to define it in a general way. Already data quality is a multidimensional concept, difficult to characterize in precise definitions even in the case of well-structured data. Big data add two further dimensions of complexity: (i) being “ very ” source specific , and for this we adopt the interesting UNECE classification, and (ii) being highly unstructured and schema-less , often without golden standards to refer to or very difficult to access. After providing a tutorial on data quality in traditional contexts, we analyze big data by providing insights into the UNECE classification, and then, for each type of data source, we choose a specific instance of such a type (notably deep Web data, sensor-generated data, and Twitters/short texts) and discuss how quality dimensions can be defined in these cases. The overall aim of the paper is therefore to identify further research directions in the area of big data quality, by providing at the same time an up-to-date state of the art on data quality.

Nowadays services are fast evolving into the coarse-grained composite services by mash up technology in both business and IT levels. It is quite important for both customers and composite service providers (called "broker") to measure whether the offered services would satisfy customers' demands. However, recent researchers use only functional aspects and QoS features to describe customer's demand and provider's capability. QoS are not enough to accurately and comprehensively describe the agreement between the customer and the provider in terms of NFPs of the requested/offered service. Therefore, this paper proposes a formal model to describe the service agreement in terms of functional and non-functional aspects respectively using state transition and service contract. In addition, we discuss the contract conflict detection and contract composition rules, and then we provide an algorithm for generating composite service contract. Finally, the paper uses an entertainment ticketing service as an example to analyze and verifies the validity of the model mentioned above.

This article investigates the evolution of data quality issues from traditional structured data managed in relational databases to Big Data. In particular, the paper examines the nature of the relationship between Data Quality and several research coordinates that are relevant in Big Data, such as the variety of data types, data sources and application domains, focusing on maps, semi-structured texts, linked open data, sensor & sensor networks and official statistics. Consequently a set of structural characteristics is identified and a systematization of the a posteriori correlation between them and quality dimensions is provided. Finally, Big Data quality issues are considered in a conceptual framework suitable to map the evolution of the quality paradigm according to three core coordinates that are significant in the context of the Big Data phenomenon: the data type considered, the source of data, and the application domain. Thus, the framework allows ascertaining the relevant changes in data quality emerging with the Big Data phenomenon, through an integrative and theoretical literature review.

In medium-big enterprise it is quite typical that the database architecture is defined through a sequence of projects and realizations that result a number of different and sometime overlapping data sources. This trend is worsened by merger and acquisition activities that add in existing data architecture new data sources from external organizations. Data fragmentation reduces significantly the possibility to exploit organizational information assets and it needs the building of a data integration architecture. This architecture allows the organization to access to data stored by heterogeneous data sources and to manage updates through a unified view of this data. In this paper we present an original framework able to support the evolution of data architecture by identifying the optimal solution that maximize the quality of the overall architecture within a given cost threshold. In particular, we focus on Publish and Subscribe as solution for data architecture.

Integrated repositories of conceptual schemas provide organizations dealing with a large amount of data sources with an integrated view on the information they manage. Making schema repositories compliant with the Web and with the Web knowledge technologies has become crucial today. In this paper we present an approach to conceptual metadata management based on the design and the publication of repositories of linked Web schemas organized by abstraction. Schemas and schema mappings are represented in the repositories by means of a SKOS extension defined in the paper. The language makes the schemas reciprocally cross-linked, providing native Web-based browsing and search functionalities. Abstraction-based schema integration primitives provide the building blocks for the organization of the repositories: loose schema mappings are based on abstraction relations and the repository is organized into levels of abstraction; the design of the repository is based on the progressive abstraction and integration of source schemas. The approach is compliant with state-of-the-art tools developed in the semantic Web, which provide tool support for the design and publication on the Web of repositories of linked schemas.

Conceptual schema integration can be exploited at the conceptual metadata level to provide organizations that deal with a large amount of data sources with an integrated view on the overall information managed. In this paper we discuss the kind of language that can be exploited for such conceptual-level integration tasks in the large, and we introduce the ER dialect called Abstract ERIA (AERIA). The introduction of such a language is based on theoretical considerations and on past experiences in conceptual schema integration. The language is provided with a Web compliant front-end concrete syntax based on OWL-DL to support the compact design of the schema and the definition of integration and abstraction relations between the schema elements. A formal semantic interpretation of the AERIA language is discussed; this interpretation allows for a translation of AERIA schemas into standard Web ontologies to support model reuse and exchange.

Many available services have been designed for a single-channel world, Web and Internet typically. In a real world scenario, an ever-growing number of users take advantage of different kinds of communication channels and devices. In this paper, we propose a methodology to formalize the re-design process of these services to support multi-channel access in different contexts. The methodology considers the channel characteristics, the location of users and the context of use to characterize the new services. It has been tested in a case study: the Italian National Project of Identification and Registration of Bovine Animals.

In many enterprises the presence of heterogenous legacy information systems is pervasive, nevertheless the different component organizations need to cooperate in order to offer new services. The Distributed Object Computing is a valid approach for the definition of a cooperative model among heterogeneous legacy information systems, but few methodologies and architectures explicitly address these issues. This paper describes a case study (or better, a set of case studies) in which these issues were addressed: it is the Cooperative Architecture over the Unitary Network of the Italian Public Administration. Then it proposes some methodological suggestions, stemming from the case studies, for the development of cooperative systems based on distributed object middleware.

The data dictionary contains the description of all types of data produced, managed, exchanged, and maintained in an organization. Data descriptions (very often hundreds of schemas) should be organized in such a way to allow all the users of the information system to understand the meaning of data and their relationships. To this end, a set of structuring primitives for a dictionary of entity relationship data schemas is presented. The formal properties of such structuring primitives are investigated, and the feasibility of their usage is shown by providing a methodology for dictionary design.>

The state of the art in automatic graph drawing is reviewed, with special attention to the readability of information system diagrams. Existing results in the literature are compared, and a comprehensive algorithmic approach to the problem is proposed. The algorithm presented draws graphs on a grid and is suitable for both undirected graphs and mixed graphs that contain as subgraphs hierarchic structures. Several applications of GIOTTO, a graphic tool that embodies the aforementioned facility, are shown.>

A layout algorithm is presented that allows the automatic drawing of data flow diagrams, a diagrammatic representation widely used in the functional analysis of information systems. A grid standard is defined for such diagrams, and aesthetics for good readability are identified. The layout algorithm receives as input an abstract graph specifying connectivity relations between the elements of the diagram, and produces as output a corresponding diagram according to the aesthetics. The basic strategy is to build incrementally the layout; first, a good topology is constructed with few crossings between edges; subsequently, the shape of the diagram is determined in terms of angles appearing along edges. and finally dimensions are given to the graph, obtaining a grid skeleton for the diagram.

Article Free Access Share on Database design: methodologies, tools, and environments (panel session) Authors: Al Hershey Database Design Inc., 2020 Hogback Road, Ann Arbor, MI Database Design Inc., 2020 Hogback Road, Ann Arbor, MIView Profile , George Gardarin Universite' de Parts VI, 4 place Jussieu, 75230 Paris-Cedex Universite' de Parts VI, 4 place Jussieu, 75230 Paris-CedexView Profile , David Reiner Computer Corporation of America, Four Cambridge Center, Cambridge, MA Computer Corporation of America, Four Cambridge Center, Cambridge, MAView Profile , Editors: Carlo Batini Dipartimento di Informatica e Sistemistica, Universita' di Roma "La Sapienza", Via Buonarroti, 12 - 00184 Roma Dipartimento di Informatica e Sistemistica, Universita' di Roma "La Sapienza", Via Buonarroti, 12 - 00184 RomaView Profile , Stefano Ceri Dipartimento di Flettronica, Politecnico di Milano, Piazza Leonardo Da Vinci, 32 - 20133 Milano Dipartimento di Flettronica, Politecnico di Milano, Piazza Leonardo Da Vinci, 32 - 20133 MilanoView Profile Authors Info & Claims SIGMOD '85: Proceedings of the 1985 ACM SIGMOD international conference on Management of dataMay 1985Pages 148–150https://doi.org/10.1145/318898.318913Published:01 May 1985Publication History 4citation512DownloadsMetricsTotal Citations4Total Downloads512Last 12 Months13Last 6 weeks1 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

The conceptual design of databases is usually seen as divided into two steps: view modeling, during which user requirements are formally expressed by means of several user oriented conceptual schemata, and schema integration, whose goal is to merge such schemata into a unique global conceptual schema. This paper is devoted to describe a methodology for schema integration. An enriched entity relationship model is chosen as the data model. The integration process consists of three steps: first, several types of conflicts between the different user schemata are checked and solved; second, schemata are merged into a draft integrated schema, that is, third, enriched and restructured according to specific goals.