Ivan Bedini

Transforming XML Schema to OWL Using Patterns

One of the promises of the Semantic Web is to support applications that easily and seamlessly deal with heterogeneous data. Most data on the Web, however, is in the Extensible Markup Language (XML) format, but using XML requires applications to understand the format of each data source that they access. To achieve the benefits of the Semantic Web involves transforming XML into the Semantic Web language, OWL (Ontology Web Language), a process that generally has manual or only semi-automatic components. In this paper we present a set of patterns that enable the direct, automatic transformation from XML Schema into OWL allowing the integration of much XML data in the Semantic Web. We focus on an advanced logical representation of XML Schema components and present an implementation, including a comparison with related work.

Modeling performance of a parallel streaming engine: bridging theory and costs

While data are growing at a speed never seen before, parallel computing is becoming more and more essential to process this massive volume of data in a timely manner. Therefore, recently, concurrent computations have been receiving increasing attention due to the widespread adoption of multi-core processors and the emerging advancements of cloud computing technology. The ubiquity of mobile devices, location services, and sensor pervasiveness are examples of new scenarios that have created the crucial need for building scalable computing platforms and parallel architectures to process vast amounts of generated streaming data. In practice, efficiently operating these systems is hard due to the intrinsic complexity of these architectures and the lack of a formal and in-depth knowledge of the performance models and the consequent system costs. The Actor Model theory has been presented as a mathematical model of con- current computation that had enormous success in practice and inspired a number of contemporary work in this area. Recently, the Storm system has been presented as a realization of the principles of the Actor Model theory in the context of the large scale processing of streaming data. In this paper, we present, to the best of our knowledge, the first set of models that formalize the performance characteristics of a practical distributed, parallel and fault-tolerant stream processing system that follows the Actor Model theory. In particular, we model the characteristics of the data flow, the data processing and the system management costs at a fine granularity within the different steps of executing a distributed stream processing job. Finally, we present an experimental validation of the described performance models using the Storm system.

Towards the optimization of a parallel streaming engine for telco applications

Parallel and distributed computing is becoming essential to process in real time the increasingly massive volume of data collected by telecommunications companies. Existing computational paradigms such as MapReduce (and its popular open-source implementation Hadoop) provide a scalable, fault tolerant mechanism for large scale batch computations. However, many applications in the telco ecosystem require a real time, incremental streaming approach to process data in real time and enable proactive care. Storm is a scalable, fault tolerant framework for the analysis of real time streaming data. In this paper we provide a motivation for the use of real time streaming analytics in the telco ecosystem. We perform an experimental investigation into the performance of Storm, focusing in particular on the impact of parameter configuration. This investigation reveals that optimal parameter choice is highly non-trivial and we use this as motivation to create a parameter configuration engine. As first steps towards the creation of this engine we provide a deep analysis of the inner workings of Storm and provide a set of models describing data flow cost, central processing unit (CPU) cost, and system management cost.

A smart campus prototype for demonstrating the semantic integration of heterogeneous data

This paper describes the implementation of a Smart Campus application prototype that integrates heterogeneous data using semantic technologies. The prototype is based on a layered semantic architecture that facilitates semantic data access and integration using OWL, SWRL and SPARQL. The focus of the paper is on the prototype implementation and the lessons learned from its development.

A flexible service selection for executing virtual services

With the adoption of a service-oriented paradigm on the Web, many software services are likely to fulfil similar functional needs for end-users. We propose to aggregate functionally equivalent software services within one single virtual service, that is, to associate a functionality, a graphical user interface (GUI), and a set of selection rules. When an end user invokes such a virtual service through its GUI to answer his/her functional need, the software service that best responds to the end-user’s selection policy is selected and executed and the result is then rendered to the end-user through the GUI of the virtual service. A key innovation in this paper is the flexibility of our proposed service selection policy. First, each selection policy can refer to heterogeneous parameters (e.g., service price, end-user location, and QoS). Second, additional parameters can be added to an existing or new policy with little investment. Third, the end users themselves define a selection policy to apply during the selection process, thanks to the GUI element added as part of the virtual service design. This approach was validated though the design, implementation, and testing of an end-to-end architecture, including the implementation of several virtual services and utilizing several software services available today on the Web.