Raúl Ruggia

Data warehouse design: a schema-transformation approach

This paper addresses DW design problems, with the goal of improving the DW logical design process. Some of the existing work in transformation oriented methodologies for DW design construct the DW starting from an entity-relationship model of the source database, and arrive to a conceptual or high-level-logical dimensional model of the DW. We propose a mechanism for obtaining the DW logical schema through pre-defined transformations applied to the source logical schema, which can be used as a complement to the existing DW design methodologies. The transformations allow a refined logical design of the DW and provide a trace of the design and a mapping between the source and DW logical structures.

Addressing QoS issues in service based systems through an adaptive ESB infrastructure

As service-based systems operate in an increasingly distributed and dynamic environment, addressing Quality of Service (QoS) issues at runtime has become an important and difficult to achieve challenge. The Enterprise Service Bus (ESB), one of the current preferred middleware technologies to support the development of service-based systems, provides built-in mediation capabilities (e.g. message transformation and routing) that allow addressing several QoS requirements. However, the configuration of these capabilities cannot usually be performed automatically at runtime, which restricts the rapid responsiveness of the system. This paper proposes ESB-based solutions to address QoS issues in service-based systems. More specifically, the paper focuses on dealing with response time and service saturation issues. The solutions leverage ESB mediation capabilities and they can be automatically and dynamically applied at runtime. Additionally, the solutions are based on commonly supported ESB patterns, so they are likely to be applied in most ESB products.

Managing source schema evolution in web warehouses

Web Data Warehouses have been introduced to enable the analysis of integrated Web data. One of the main challenges in these systems is to deal with the volatile and dynamic nature of Web sources. In this work we address the effects of adding/removing/changing Web sources and data items to the Data Warehouse (DW) schema. By managing source evolution we mean the automatic propagation of these changes to the DW. The proposed approach is based on a wrapper/mediator architecture, which reduces the impact of Web source changes on the DW schema. This paper presents this architecture and analyses some selected evolution cases in the context of Web DW.

Towards dynamic adaptation within an ESB-based service infrastructure layer

Service-oriented systems increasingly need to be self-adaptive in order to respond to dynamic business requirements and to satisfy quality of service conditions in a highly distributed context. Achieving such self-adaptive behavior requires a comprehensive approach throughout the different service-oriented architecture (SOA) layers to avoid, for example, conflicting adaptation actions. In turn, Enterprise Service Buses (ESBs) provide several out-of-the-box mediation features (e.g. message transformation, routing, monitoring) that enable adaptation at the infrastructure layer. However, dynamic adaptation (i.e. adaptation at runtime), a fundamental requirement in self-adaptive systems, is still an open issue in ESB-based platforms. This paper presents an approach that leverages ESBs mediation features to provide dynamic adaptation capabilities within an ESB-based service infrastructure layer. This work, which is based on concepts and frameworks defined within the S-Cube project, intends to be a step forward in developing a comprehensive approach to support self-adaptive service-oriented systems.

An Adaptive Enterprise Service Bus Infrastructure for Service Based Systems

Service-based systems (SBS) increasingly need adaptation capabilities to agilely respond to unexpected changes (e.g. regarding quality of service). The Enterprise Service Bus (ESB), a recognized infrastructure to support the development of SBS, provides native mediation capabilities (e.g. message transformation) which can be used to perform adaptation actions. However, the configuration of these capabilities cannot usually be performed at runtime. To deal with this limitation, Adaptive ESB Infrastructures have been proposed which leverage their mediation capabilities to deal with adaptation requirements in SBSs in an automatic and dynamic way at runtime. This paper presents a JBossESB-based implementation of an Adaptive ESB Infrastructure and demonstrates its operation by describing their main functionalities. The paper also presents an evaluation of the implemented solution.

A service-oriented integration platform to support a joined-up e-government approach: the uruguayan experience

E-Government Platforms have become a key tool to support the development of e-government in many countries. They usually provide infrastructure and services that facilitate the interconnection between the information systems of public agencies, provide common services that generate economy of scale, and encourage the implementation of multi-agency services. In particular, the Uruguayan E-Government Platform has the general goal of enabling and promoting the development of e-government services in Uruguay. The platform, which follows a joined-up approach, consists of an Interoperability Platform and a set of Crosscutting Services. It implements a service-oriented architecture, leveraging the Web Services technology, to expose, use and combine government functionality implemented by public agencies. This paper presents the Uruguayan E-Government Platform focusing on two components of the Interoperability Platform: the Middleware Infrastructure and the Security System. It also evaluates its first years of operation which have shown that, although there are still many challenges to be addressed, the platform is a key enabler for developing a joined-up e-government approach in Uruguay.

Run-Time Verification of Behaviour-Aware Mashups in the Internet of Things

With the new vision of the Internet of Things, physical world entities are integrated into virtual world things. Then, the Internet of Things could benefit from the Web Service architecture like today’s Web does; so Future service-oriented Internet things will offer their functionality via service-enabled interfaces. As demonstrated in previous work, there is a need of considering the behaviour of things to develop applications in a more rigorous way. We proposed a lightweight model for representing such behaviour based on the service-oriented paradigm and extending the standard DPWS profile to specify the order with which things can receive messages. To check whether a mashup of things respects the behaviour, specified at design-time, we proposed a static verification. However, at run-time a thing may change its behaviour or receive requests from instances of different mashups. Then, it is required to check and detect dynamically possible invalid invocations provoked by changes of behaviour. Here, we extend our static verification with an approach based on mediation techniques and complex event processing to detect and inhibit invalid invocations. The solution automatically generates the required elements to perform run-time validation of invocations. It may be extended to validate other issues.

Qbox-Services: Towards a Service-Oriented Quality Platform

The data quality market is characterized by a sparse offer of tools, providing individual functionalities which have their own interest with respect to quality assessment. But interoperating among these tools remains a technical challenge because of the heterogeneity of their models and access patterns. On the other side, quality analysts require more and more integration facilities that allow them to consolidate and aggregate multiple quality measures acquired from different observations. The QBox platform, developed within the ANR Quadris project, aims at filling this gap by supplying a service-based integration infrastructure that allows interoperability among several quality tools and provides an OLAP-based quality model to support multidimensional analysis. This paper focuses on the architectural principles of this infrastructure and illustrates its use through specific examples of quality services.

Analyzing and Evaluating Data Freshness in Data Integration Systems

Data freshness has been identified as one of the most important data quality attributes in information systems. This importance increases particularly in the context of systems composed of a large set of autonomous data sources where integrating data having different freshness may lead to semantic problems. This paper addresses the problem of evaluating data freshness in a data integration system and presents a taxonomy to classify different scenarios where data freshness can be evaluated. We propose a framework for modeling the data integration system and performing freshness evaluation and we illustrate the approach for a particular scenario.

A Toolkit for Reuse in Conceptual Modelling

This paper proposes a toolkit for applying Reuse in Conceptual Modelling. The main objective is to cope with the problems of complexity in the Conceptual Modelling activity. In a long-term perspective this proposition intends to settle the basis for a larger application of Reuse in Information System development. While research in Software Reuse has revealed that the application of Reuse in software development is extremely difficult, Conceptual Modelling appears as a more promising area because it manipulates simpler objects: conceptual schemas.