A Logical Verification Methodology for Service-Oriented Computing

We introduce a logical verification methodology for checking behavioural properties of service-oriented computing systems. Service properties are described by means of SocL, a branching-time temporal logic that we have specifically designed to express in an effective way distinctive aspects of services, such as, e.g., acceptance of a request, provision of a response, and correlation among service requests and responses. Our approach allows service properties to be expressed in such a way that they can be independent of service domains and specifications. We show an instantiation of our general methodology that uses the formal language COWS to conveniently specify services and the expressly developed software tool CMC to assist the user in the task of verifying SocL formulae over service specifications. We demonstrate feasibility and effectiveness of our methodology by means of the specification and the analysis of a case study in the automotive domain

Regulating Data Exchange in Service Oriented Applications

We define a type system for COWS, a formalism for specifying and combining services, while modelling their dynamic behaviour. Our types permit to express policies constraining data exchanges in terms of sets of service partner names attachable to each single datum. Service programmers explicitly write only the annotations necessary to specify the wanted policies for communicable data, while a type inference system (statically) derives the minimal additional annotations that ensure consistency of services initial configuration. Then, the language dynamic semantics only performs very simple checks to authorize or block communication. We prove that the type system and the operational semantics are sound. As a consequence, we have the following data protection property: services always comply with the policies regulating the exchange of data among interacting services. We illustrate our approach through a simplified but realistic scenario for a service-based electronic marketplace

Papular-purpuric gloves and socks syndrome due to parvovirus B19: a report of two simultaneous cases in cohabitant families.

The so-called papular-purpuric gloves and socks syndrome (PPGSS) is a condition characterized by acute onset of intense erythema, edema and petechiae with a typical localization on the hands and feet, besides mucosal lesions of the oral cavity. The syndrome has a favorable and self-limited course, requiring only a symptomatic therapy. In the 50% of the cases described in literature (ninety cases in 22 years), is documented an acute infection caused by parvovirus B19 and in only two cases the onset of PPGSS is reported among different members of the same family. The aim of the work is to describe two cases of PPGSS arisen during a short time period in two family members affected by an acute parvovirus B19 infection found by serum sampling. The peculiarity of the study was the infrequence of the syndrome and the rareness of the description of PPGSS in rheumatology. This syndrome is usually described in dermatology, but it is also interesting for the rheumatologist because it comes in differential diagnosis with various autoimmune diseases

Safety of anti-tumor necrosis factor-α therapy in patients with rheumatoid arthritis and chronic hepatitis C virus infection

The prevalence of concurrent rheumatoid arthritis (RA) and hepatitis C virus (HCV) infection is probably underestimated because of the increasing spread of this virus worldwide, especially in developing countries. In these patients, anti-tumor necrosis factor-alpha (anti-TNF-alpha) therapy may aggravate hepatitis and increase viremia. We evaluated the safety of these treatments, which remain controversial. Thirty-one HCV-positive patients (23 women, 8 men, mean age 59+/-13 yrs, mean disease duration 13+/-11.5 SD yrs) with active RA [Disease Activity Score 28 (DAS28)>3.2] unresponsive to conventional therapies were treated with TNF-alpha blockers (infliximab 11, etanercept 17, adalimumab 3) at standard dosages. Safety and efficacy were evaluated at the third month of treatment and at the patient's last observation. A significant clinical-serological improvement was recorded at the 3-month reevaluation. Mean values of patients assessment of general health on visual analog scale (range 0.100) decreased from 69+/-29 (SD) to 35+/-27 (por=2 log10) in 4 cases. Previous observations had suggested the safety of TNF-alpha blockers for treatment of RA in patients with concurrent HCV infection. Given the clinical-therapeutic implications, our results support the safety of TNF-alpha blockers in patients with HCV, provided there is close monitoring of clinical and virological data (mainly ALT and HCV viremia)

Orchestrating Tuple-based Languages

The World Wide Web can be thought of as a global computing architecture supporting the deployment of distributed networked applications. Currently, such applications can be programmed by resorting mainly to two distinct paradigms: one devised for orchestrating distributed services, and the other designed for coordinating distributed (possibly mobile) agents. In this paper, the issue of designing a pro- gramming language aiming at reconciling orchestration and coordination is investigated. Taking as starting point the orchestration calculus Orc and the tuple-based coordination language Klaim, a new formalism is introduced combining concepts and primitives of the original calculi. To demonstrate feasibility and effectiveness of the proposed approach, a prototype implementation of the new formalism is described and it is then used to tackle a case study dealing with a simplified but realistic electronic marketplace, where a number of on-line stores allow client applications to access information about their goods and to place orders

Reasoning About a Service-oriented Programming Paradigm

This paper is about a new way for programming distributed applications: the service-oriented one. It is a concept paper based upon our experience in developing a theory and a language for programming services. Both the theoretical formalization and the language interpreter showed us the evidence that a new programming paradigm exists. In this paper we illustrate the basic features it is characterized by

A criterion for separating process calculi

We introduce a new criterion, replacement freeness, to discern the relative expressiveness of process calculi. Intuitively, a calculus is strongly replacement free if replacing, within an enclosing context, a process that cannot perform any visible action by an arbitrary process never inhibits the capability of the resulting process to perform a visible action. We prove that there exists no compositional and interaction sensitive encoding of a not strongly replacement free calculus into any strongly replacement free one. We then define a weaker version of replacement freeness, by only considering replacement of closed processes, and prove that, if we additionally require the encoding to preserve name independence, it is not even possible to encode a non replacement free calculus into a weakly replacement free one. As a consequence of our encodability results, we get that many calculi equipped with priority are not replacement free and hence are not encodable into mainstream calculi like CCS and pi-calculus, that instead are strongly replacement free. We also prove that variants of pi-calculus with match among names, pattern matching or polyadic synchronization are only weakly replacement free, hence they are separated both from process calculi with priority and from mainstream calculi.Comment: In Proceedings EXPRESS'10, arXiv:1011.601