José Viterbo

Open government data in Brazil

This article discusses the current status of open government data in Brazil and summarizes the lessons learned from publishing Brazilian government data as linked data.

A Middleware Architecture for Context-Aware and Location-Based Mobile Applications

The development of location and context-aware applications is greatly facilitated by the use of context-provisioning middleware. However, development of such applications still remains a challenge from the point of view of software engineering. In this paper we present MoCA, a service-oriented middleware architecture that supports the development and deployment of distributed context-aware applications for mobile users. Besides explaining its main services and APIs, we discuss in which ways the MoCA architecture supports some well-known software engineering principles that apply to the design and implementation of context-aware applications. Furthermore, we give an overview of its usage and present the most notable prototype applications that have been developed on the top of MoCA.

ContextNet: context reasoning and sharing middleware for large-scale pervasive collaboration and social networking

In this paper, we describe ContextNet, a middleware architecture with context services for wide- and large-scale pervasive collaborative applications. It also provides context-based reasoning over data and events generated by autonomously moving users or their vehicles.

StdTrip: Promoting the Reuse of Standard Vocabularies in Open Government Data

Linked Data is the standard generally adopted for publishing Open Government Data. This operation requires that a myriad of public information datasets be converted to a set of RDF triples. A major step in this process is deciding how to represent the database schema concepts in terms of RDF classes and properties. This is done by mapping database concepts to a vocabulary, which will be used as the base for generating the RDF representation. The construction of this vocabulary is extremely important, because it determines how the generated triples interlink the resulting dataset with other existing ones. However, most engines today provide support only to the mechanical process of transforming relational to RDF data. In this chapter, we discuss this process and present the StdTrip framework, a tool that supports the conceptual modeling stages of the production of RDF datasets, promoting the reuse of W3C recommended standard RDF vocabularies or suggesting the reuse of non-standard vocabularies already adopted by other RDF datasets.

RDB2RDF plugin: relational databases to RDF plugin for eclipse

RDB2RDF is the process by which a relational database schema (RDB) is transformed into a set of RDF triples. A major step in this process is deciding how to represent database schema concepts in terms of RDF classes and properties. This correlation is described in the RDB2RDF mapping file, which is used as the base for the generation of RDF triples. Most RDB2RDF engines today provide support to the mechanical process of transforming RDB to RDF, each with its own mapping language. Due to this fact, the W3C RDB2RDF Working Group has been working to standardize a language to map relational data to RDF called R2RML. Part of their efforts is directed to fostering the development of methods, tools and techniques to support standard RDB2RDF mapping strategies. In this paper, we introduce an Eclipse plug-in that supports the standard RDB to RDF Mapping Language (R2RML) to produce Direct Mappings in RDF.

A Formal Framework for Modeling Context-Aware Behavior in Ubiquitous Computing

A formal framework to contextualize ontologies, proposed in [3], provides several ways of composing ontologies, contexts or both. The proposed algebra can be used to model applications in which the meaning of an entity depends on environment constraints or where dynamic changes in the environment have to be considered. In this article we use this algebra to formalize the problem of interpreting context information in ubiquitous systems, based on a concrete scenario. The main goal is to verify, on one hand, how the formal approach can contribute with a better understanding of the fundamental concepts of ubiquitous computing and, on the other hand, if this formal framework is flexible and rich enough to adequately express specific characteristics of the concrete application domain and scenario.

A multi-agent architecture to support ubiquitous applications in smart environments

The implementation of Ambient Intelligence (AmI) requires the support of tools and technologies capable of interpreting large quantities of data collected from different sources comprising sensors networks, mobile devices, social networks and other systems. The agent-oriented paradigm is particularly appropriate for such a scenario, because agents offer some important features, like proactive and reactive reasoning, autonomy, social abilities and learning. In this work we propose a middleware architecture to support the development of applications in the scope of Smart Cities, describing its main characteristics and requirements. The Devices, Environments and Social networks Integration Architecture (DESIA) proposal includes emerging technologies such as social networks, cloud computing and digital ecosystems, emphasizing security and privacy, key aspects not always covered by other architectures.

RDB2RDF: A relational to RDF plug-in for Eclipse

The process of transforming data stored in relational databases (RDBs) into sets of Resource Description Framework (RDF) triples is known as triplification or RDB2RDF. It consists of two consecutive operations, schema extraction and data conversion. Schema extraction is a process similar to creating an external schema, and contains a collection of database views. The data conversion is divided into two steps. The first step consists of deciding how to represent database schema concepts in terms of RDF classes and properties, defining an RDB2RDF mapping. The second step consists of the actual conversion of relational data to RDF data instances, based on the mapping previously defined. Although the schema extraction is very well understood, the data conversion operation is still murky. Indeed, the World Wide Web Consortium RDB2RDF Working Group has been working to define a standard language, called R2RML, to describe RDB2RDF mapping files. The definition of the R2RML, however, is still undergoing changes. In this paper, we introduce an Eclipse plug‐in that supports the entire conversion process. Its architecture takes into consideration the specificities of the triplification process by providing a modular structure that encapsulates the stable and well‐understood components separately from the volatile, change‐prone mapping strategies. The latter are accessible via a well‐defined interface to promote information hiding and separation of concerns and to facilitate evolution. Copyright

A Two-Tiered Approach for Decentralized Reasoning in Ambient Intelligence

This article proposes a two-tiered model for decentralized reasoning in which two interacting parties with access to different context information perform a cooperative strategy to infer situations.

Visualizing Aedes aegypti infestation in urban areas: A case study on open government data mashups

Publishing open government data and displaying the related information is a task that requires systematization and the use of various technologies. Due to technical limitations (dependence on technological platforms, for example), this is not a standard practice among government system developers. In this work, we present a case study that involves the creat ion of a map to visualiz e information about the infestation of Aedes aegypti (dengue vector) in the municipality of Cuiaba , based on the selection and analysis of open data . This case study not only demo nstrates that offering an easy way for presenting information on public health brings benefits to the community, but it also discusses a solution that serves as a strategy for government agencies to make use of resources related to open data.