Integrated Modeling and Verification of Real-Time Systems through Multiple Paradigms

Complex systems typically have many different parts and facets, with different characteristics. In a multi-paradigm approach to modeling, formalisms with different natures are used in combination to describe complementary parts and aspects of the system. This can have a beneficial impact on the modeling activity, as different paradigms an be better suited to describe different aspects of the system. While each paradigm provides a different view on the many facets of the system, it is of paramount importance that a coherent comprehensive model emerges from the combination of the various partial descriptions. In this paper we present a technique to model different aspects of the same system with different formalisms, while keeping the various models tightly integrated with one another. In addition, our approach leverages the flexibility provided by a bounded satisfiability checker to encode the verification problem of the integrated model in the propositional satisfiability (SAT) problem; this allows users to carry out formal verification activities both on the whole model and on parts thereof. The effectiveness of the approach is illustrated through the example of a monitoring system.Comment: 27 page

A Metric Encoding for Bounded Model Checking (extended version)

In Bounded Model Checking both the system model and the checked property are translated into a Boolean formula to be analyzed by a SAT-solver. We introduce a new encoding technique which is particularly optimized for managing quantitative future and past metric temporal operators, typically found in properties of hard real time systems. The encoding is simple and intuitive in principle, but it is made more complex by the presence, typical of the Bounded Model Checking technique, of backward and forward loops used to represent an ultimately periodic infinite domain by a finite structure. We report and comment on the new encoding technique and on an extensive set of experiments carried out to assess its feasibility and effectiveness

Combining dental and skeletal evidence in age classification: Pilot study in a sample of Italian sub-adults

Background: Dental and skeletal maturation have proved to be reliable evidence for estimating age of children and prior studies and internationally accredited guidelines recommend to evaluate both evidence in the same subject to reduce error in age prediction. Nevertheless the ethical and legal justification of procedures that imply a double exposition of children stands as a relevant issue. This study aims to evaluate the accuracy of age estimation provided by a combination of skeletal and dental methods applied in the same sample of children. / Materials and methods: The sample consisted of 274 orthopantomographies and left hand-wrist X-rays of Italian children, (aged between 6 and 17 years) taken on the same day. Greulich and Pyle’s (GP), Tanner-Whitehouse’s version 3 (TW3) and Willems’ (W) and the Demirjian’s (D) methods were respectively applied for estimating skeletal and dental age. A combination of skeletal and dental age estimates through Linear Discriminant Analysis (LDA) is proposed to obtain a classifier respect to an age threshold. / Results: The combination of D and TW3 obtained an improvement of accuracy in classifying female subjects respect to the 12 years threshold respect to the original methods (from about 77% using either original methods to 83.3% combining TW3 + D) as well as a consistent reduction of false positives rate (from 17% to 21% for original methods to 5.6% with TW3 + D). For males the LDA classifier (based on TW3 and W) enable a small improvement in accuracy, whilst the decreasing of false positives was as noticeable as for females (from 17.6 to 14.1% for original methods to 6.2% combining TW3 + W). / Conclusions: Although the study is influenced by the limited size and the uneven age distribution of the sample, the present findings support the conclusion that age assessment procedures based on both dental and skeletal age estimation can improve the accuracy and reduce the occurrence of false positives

A Theory of Sampling for Continuous-time Metric Temporal Logic

This paper revisits the classical notion of sampling in the setting of real-time temporal logics for the modeling and analysis of systems. The relationship between the satisfiability of Metric Temporal Logic (MTL) formulas over continuous-time models and over discrete-time models is studied. It is shown to what extent discrete-time sequences obtained by sampling continuous-time signals capture the semantics of MTL formulas over the two time domains. The main results apply to "flat" formulas that do not nest temporal operators and can be applied to the problem of reducing the verification problem for MTL over continuous-time models to the same problem over discrete-time, resulting in an automated partial practically-efficient discretization technique.Comment: Revised version, 43 pages

Ultrasound-guided percutaneous irrigation of calcific tendinopathy: Technical developments

Rotator cuff calcific tendinopathy (RCCT) is a common and painful shoulder disease character-ised by deposition of calcium into the rotator cuff’s tendond. Different therapeutic options have been proposed, but the ultrasound-guided percutaneous irrigation (US-PICT) is been proved as an effective and safe first-line treatment. It can be performed with a single-of a double-needle tecnique, using warm saline solution to improve the dissolution of the calcific deposit. The procedure is ended with an intrabursal injection of local anaesthetics and slow-release steroids to improve the pain relief and to prevent complications. US-PICT leads to significative improvement in the shoulder funtion and pain relief in the short and long term, with a low complications rate. (www.actabiomedica.it)