Luca Spalazzi

A minimalist approach to semantic annotations for web processes compositions

In this paper we propose a new approach to the automated composition of distributed processes described as semantic web services. Current approaches, such as those based on owl-s and wsmo, in spite of their expressive power, are hard to use in practice. Indeed, they require comprehensive and usually large ontological descriptions of the processes, and rather complex (and often inefficient) reasoning mechanisms. In our approach, we reduce to the minimum the usage of ontological descriptions of processes, so that we can perform a limited, but efficient and useful, semantic reasoning for composing web services. The key idea is to keep separate the procedural and the ontological descriptions, and to link them through semantic annotations. We define the formal framework, and propose a technique that can exploit simple reasoning mechanisms at the ontological level, integrated with effective reasoning mechanisms devised for procedural descriptions of web services.

Model Checking Semantically Annotated Services

Model checking is a formal verification method widely accepted in the web service world because of its capability to reason about service behavior at process level. It has been used as a basic tool in several scenarios such as service selection, service validation, and service composition. The importance of semantics is also widely recognized. Indeed, there are several solutions to the problem of providing semantics to web services, most of them relying on some form of Description Logic. This paper presents an integration of model checking and semantic reasoning technologies in an efficient way. This can be considered the first step toward the use of semantic model checking in problems of selection, validation, and composition. The approach relies on a representation of services at process level that is based on semantically annotated state transition systems (asts) and a representation of specifications based on a semantically annotated version of computation tree logic (anctl). This paper proves that the semantic model checking algorithm is sound and complete and can be accomplished in polynomial time. This approach has been evaluated with several experiments.

An Internet of Things ontology for earthquake emergency evaluation and response

Recent years have seen the fast-diffusion of internet-connected devices and the rise of the Internet of Things (IoT) research and application area. Research works are dealing with technologies that enable the so-called things to communicate among them and with users in order to provide data and/or accomplish tasks. This scenario is posing several challenges so that more and more researchers are dealing with them. Our work deals with the definition of both machine and human understandable descriptions of things by means of ontologies in order to enable the collaboration among physical objects and IT systems. Indeed, recent works highlighted how the IoT technology may be profitably used in several scenarios in order to accomplish complex tasks where physical objects are active participants. First, we extend the Semantic Sensor Network ontology defined by the W3C Semantic Sensor Networks Incubator Group with concepts and roles that describe actuators. This leads to the definition of a comprehensive Internet of Things ontology. Then, with the support from domain experts, we analyze the earthquake emergency scenario in order to define for it a domain ontology by means of adding domain-related concepts to the IoT ontology. Furthermore, we compare our work with others that use ontologies to formally describes things.

Semantic Web Service Selection at the Process-Level: The eBay/Amazon/PayPal Case Study

Several approaches have been proposed to tackle the selection of distributed processes described as semantic Web services. However, their practical applicability in real composition scenarios is still an open question. Addressing this problem requires on the one hand to deal with services described as stateful business processes and, on the other hand, to consider complex selection requirements concerning both the service interface and its behavior. In fact, in most existing approaches the selection is performed on the basis of the ldquofunctionalrdquo description of a service, i.e. in terms of its inputs, outputs, preconditions and effects. In this paper, we present our approach for the process-level service selection and evaluate it on a real world scenario that entails a high level of complexity: the eBay Web Services,the Amazon E-Commerce Services and the e-payment service offered by PayPal. The approach is based on a representation of services at the process level that is based on BPEL and WSDL specifications and that extends these standard specifications with minimal semantic annotations that permit to perform an efficient and yet useful, semantic reasoning for the process-level selection of Web services.

FCFA: A semantic-based federated cloud framework architecture

Cloud Computing is a paradigm that applies a service model on infrastructures, platforms and software. In the last few years, this new idea has been showing its potentials and how, in the long run, it will affect Information Technology and the act of interfacing to computation and storage. This article introduces the FCFA project, a framework for an ontology-based resource life-cycle management and provisioning in a federated Cloud Computing infrastructure. Federated Clouds are presumably the first step toward a Cloud 2.0 scenario where different providers will be able to share their assets in order to create a free and open Cloud Computing marketplace. The contribution of this article is a redesign of a Cloud Computing infrastructure architecture from the ground-up, leveraging semantic web technologies and natively supporting a federated resource provisioning.

Cooperation Strategies for Information Integration

We discuss and analyse cooperation strategies for rewriting queries in a mediator architecture. According to this approach, the mediated schema of each mediator is dynamically updated through the cooperation with information sources and other mediators, strongly influenced by the queries submitted by a consumer. This approach allows a mediator to face systems where information sources and consumer needs are dynamic. From the analysis of different cooperation strategies arises that it is more efficient and effective to directly cooperate with information sources when the sources are few. Otherwise, it is more efficient to cooperate with other mediators.

A Logic of Belief and a Model Checking Algorithm for Security Protocols

Model checking is a very successful technique which has been applied in the design and verification of finite state concurrent reactive processes. In this paper we show how this technique can be used for the verification of security protocols using a logic of belief. The underlying idea is to treat separately the temporal evolution and the belief aspects of principals. In practice, things work as follows: when we consider the temporal evolution of a principal we treat belief atoms (namely, atomic formulae expressing belief) as atomic propositions. When we deal with the beliefs of a principal A, we model its beliefs about another principal B as the fact that A has access to a representation of B as a process. Then, any time it needs to verify the truth value of some belief atom about B, e.g., B B o, A simply tests whether, e.g., o holds in its (appropriate) representation of B. Beliefs are essentially used to control the “jumping” among processes. Our approach allows us to reuse the technology and tools developed in model checking.

A dynamic logic for acting, sensing, and planning

This paper is a first attempt towards a theory for reactive planning systems, i.e. systems able to plan and control execution of plans in a partially known and unpredictable environment. We start from an experimental real world application developed at IRST, discuss some of the fundamental requirements and propose a formal theory based on these requirements. The theory takes into account the following facts: (1) actions may fail, since they correspond to complex programs controlling sensors and actuators which have to work in an unpredictable environment; (2) actions need to acquire information from the real world by activating sensors and actuators; (3) actions need to generate and execute plans of actions, since the planner needs to activate different special purpose planners and to execute the resulting plans.

Gait parameter and event estimation using smartphones

BACKGROUND AND OBJECTIVES The use of smartphones can greatly help for gait parameters estimation during daily living, but its accuracy needs a deeper evaluation against a gold standard. The objective of the paper is a step-by-step assessment of smartphone performance in heel strike, step count, step period, and step length estimation. The influence of smartphone placement and orientation on estimation performance is evaluated as well. METHODS This work relies on a smartphone app developed to acquire, process, and store inertial sensor data and rotation matrices about device position. Smartphone alignment was evaluated by expressing the acceleration vector in three reference frames. Two smartphone placements were tested. Three methods for heel strike detection were considered. On the basis of estimated heel strikes, step count is performed, step period is obtained, and the inverted pendulum model is applied for step length estimation. Pearson correlation coefficient, absolute and relative errors, ANOVA, and Bland-Altman limits of agreement were used to compare smartphone estimation with stereophotogrammetry on eleven healthy subjects. RESULTS High correlations were found between smartphone and stereophotogrammetric measures: up to 0.93 for step count, to 0.99 for heel strike, 0.96 for step period, and 0.92 for step length. Error ranges are comparable to those in the literature. Smartphone placement did not affect the performance. The major influence of acceleration reference frames and heel strike detection method was found in step count. CONCLUSION This study provides detailed information about expected accuracy when smartphone is used as a gait monitoring tool. The obtained results encourage real life applications.

Agent-based transactions into decentralised P2P

The Peer-to-Peer (P2P) approach is considered an innovative paradigm in distributed computing. Nevertheless, P2P tools are not able to exchange complex data and to deal with heterogeneity and data management problems. In order to overcome some of these limitations, this paper proposes to use an agent based cooperative information system. We describe the fundamental agent roles inside the system: mediator, facilitator, planner and wrapper. In particular, the mediator plays the main role in generating simple data management operations (transactions) according to its local knowledge.