Andrea Maurino

Methodologies for data quality assessment and improvement

The literature provides a wide range of techniques to assess and improve the quality of data. Due to the diversity and complexity of these techniques, research has recently focused on defining methodologies that help the selection, customization, and application of data quality assessment and improvement techniques. The goal of this article is to provide a systematic and comparative description of such methodologies. Methodologies are compared along several dimensions, including the methodological phases and steps, the strategies and techniques, the data quality dimensions, the types of data, and, finally, the types of information systems addressed by each methodology. The article concludes with a summary description of each methodology.

Quality assessment for Linked Data: A Survey

The development and standardization of semantic web technologies has resulted in an unprecedented volume of data being published on the Web as Linked Data (LD). However, we observe widely varying data quality ranging from extensively curated datasets to crowdsourced and extracted data of relatively low quality. In this article, we present the results of a systematic review of approaches for assessing the quality of LD. We gather existing approaches and analyze them qualitatively. In particular, we unify and formalize commonly used terminologies across papers related to data quality and provide a comprehensive list of 18 quality dimensions and 69 metrics. Additionally, we qualitatively analyze the 30 core approaches and 12 tools using a set of attributes. The aim of this article is to provide researchers and data curators a comprehensive understanding of existing work, thereby encouraging further experimentation and development of new approaches focused towards data quality, specifically for LD.

Workflow Partitioning in Mobile Information Systems

The increasing success of wireless technologies is sustaining the diffusion of mobile information systems, but the youth of the underlying technology and its peculiar characteristics are impacting the development of such systems. For example, the execution of business processes in such a context must cope with the variable and fluctuating bandwidth available to the different devices. This leads the designer to stress the independence of each actor -- by minimizing interactions and knowledge sharing -- to increase the reliability of the whole system.

A Meta-model for Non-functional Property Descriptions of Web Services

In this paper we propose a meta-model for nonfunctional property descriptions targeted to support the selection of Web Services. The approach is based on the explicit distinction between NFP offered by providers and requested by users, on the concept of policy that aggregates NFP descriptions into single entities with an applicability condition, and finally on a set of constraint operators, which is particularly relevant for NFP requests. The semantic meta-model embracing the above perspective is defined by a BNF syntax whose semantics is formalized by an ontology. The ontology has been formalized in OWL-DL and WSML to provide for logical syntax. The logic upon which the meta-model supports NFP-based selection is discussed in the paper.

Building Multi-device, Content-Centric Applications Using WebML and the W3I3 Tool Suite

In the forthcoming years, two factors will jeopardize the deployment of Web applications: supporting multi-device outputs and one-to-one personalization. These two factors will lead to an explosion of solutions, to be developed, maintained, and kept consistent; meanwhile, Web hosting companies will be subject to growing service demands and will be lacking the technical man-power required to master them. With these premises, the strength of the W3I3 tool suite is to propose a model-driven approach to Web site design. Such an approach is based on WebML, a high-level language for specifying the structure of the content of aWeb application and the organization and presentation of such a content in a Web site. In this paper, after a brief presentation of WebML, we concentrate on the W3I3 tool architecture, shown at work on case-study based on the popular site http://www.softseek.com.

On the diversity and availability of temporal information in linked open data

An increasing amount of data is published and consumed on the Web according to the Linked Data paradigm. In consideration of both publishers and consumers, the temporal dimension of data is important. In this paper we investigate the characterisation and availability of temporal information in Linked Data at large scale. Based on an abstract definition of temporal information we conduct experiments to evaluate the availability of such information using the data from the 2011 Billion Triple Challenge (BTC) dataset. Focusing in particular on the representation of temporal meta-information, i.e., temporal information associated with RDF statements and graphs, we investigate the approaches proposed in the literature, performing both a quantitative and a qualitative analysis and proposing guidelines for data consumers and publishers. Our experiments show that the amount of temporal information available in the LOD cloud is still very small; several different models have been used on different datasets, with a prevalence of approaches based on the annotation of RDF documents.

Linking temporal records

Many data sets contain temporal records which span a long period of time; each record is associated with a time stamp and describes some aspects of a real-world entity at a particular time (e.g., author information in DBLP). In such cases, we often wish to identify records that describe the same entity over time and so be able to perform interesting longitudinal data analysis. However, existing record linkage techniques ignore temporal information and fall short for temporal data.This article studies linking temporal records. First, we apply time decay to capture the effect of elapsed time on entity value evolution. Second, instead of comparing each pair of records locally, we propose clustering methods that consider the time order of the records and make global decisions. Experimental results show that our algorithms significantly outperform traditional linkage methods on various temporal data sets.

Modeling Data Entry and Operations in WebML

Web Modeling Language (WebML http://www.webml.org) is a notation for visually specifying complex Web sites at the conceptual level. All the concepts of WebML are specified both graphically and in XML; in particular, navigation and composition abstractions are based on a restricted number of hypertext components (units) which are assembled into pages and interconnected by links.

GLUE2: A Web Service Discovery Engine with Non-Functional Properties

The increasing availability of Web services asked for investigating ways to automate the discovery process. Discovery processes enhanced with semantics can be recognize to be general, but often they lack the flexibility needed in specific domains. In this paper, we propose the flexible architecture of the discovery engine Glue2, which comes with a powerful set of discovery components (for functional matching, non-functional matching, data fetching, etc.) that can be executed in different order as required by specific execution workflows.

NFP-aware Semantic Web Services Selection

The discovery of a semantic web service (SWS) is the act of locating a machine-processable description of a SWS-related resource that may have been previously unknown and that meets certain functional criteria. The increasing availability of services that offer similar functionalities requires the discovery process to be enhanced with a selection phase that considers non-functional properties (NFPs) of services. This paper proposes a model to describe these properties and a novel approach to service selection. Our approach is based on the design of matching rules by means of mediators defined by sets of rules stating the condition for successful matches. These rules are based on the ontological description of objects representing NFPs that are required and offered. In particular, we define a set of rule schemas to support mediation and matching for a class of user-defined NFP-constraints clustered according to specified constraint operators. Rules support matching for both qualitative and quantitative non-functional properties.