Twinning automata and regular expressions for string static analysis

In this paper we formalize and prove the soundness of Tarsis, a new abstract domain based on the abstract interpretation theory that approximates string values through finite state automata. The main novelty of Tarsis is that it works over an alphabet of strings instead of single characters. On the one hand, such approach requires a more complex and refined definition of the widening operator, and the abstract semantics of string operators. On the other hand, it is in position to obtain strictly more precise results than than state-of-the-art approaches. We implemented a prototype of Tarsis, and we applied it on some case studies taken from some of the most popular Java libraries manipulating string values. The experimental results confirm that Tarsis is in position to obtain strictly more precise results than existing analyses

Twinning Automata and Regular Expressions for String Static Analysis

In this paper we formalize Tarsis, a new abstract domain based on the abstract interpretation theory that approximates string values through finite state automata. The main novelty of Tarsis is that it works over an alphabet of strings instead of single characters. On the one hand, such an approach requires a more complex and refined definition of the widening operator, and the abstract semantics of string operators. On the other hand, it is in position to obtain strictly more precise results than state-of-the-art approaches. We implemented a prototype of Tarsis, and we applied it to some case studies taken from some of the most popular Java libraries manipulating string values. The experimental results confirm that Tarsis is in position to obtain strictly more precise results than existing analyses

FREEDA: Failure-Resilient, Energy-aware, and Explainable Deployment of Microservice-based Applications over Cloud-IoT Infrastructures

FREEDA is an Italian research project aimed at supporting DevOps engineers in achieving failure-resilient and environmentally sustainable deployments of microservice-based applications over the Cloud-edge computing continuum. In this article, we describe motivations, objectives and first results of the FREEDA project, and discuss how FREEDA relates to the Information Systems Engineering community

FREEDA: Failure-Resilient, Energy-aware, and Explainable Deployment of Microservice-based Applications over Cloud-IoT Infrastructures

FREEDA is an Italian research project aimed at supporting DevOps engineers in achieving failure-resilient and environmentally sustainable deployments of microservice-based applications over the Cloud-edge computing continuum. In this article, we describe motivations, objectives and first results of the FREEDA project, and discuss how FREEDA relates to the Information Systems Engineering community

Taking care of people experiencing homelessness: a community case study on the practice of the Volunteer Association “A doctor for you” in Brescia, Italy

IntroductionAlthough homelessness is a much-studied phenomenon today, statistics indicate a steady increase in homelessness globally. UN General Assembly itself recommends implementing strategies through the commitment of the various stakeholders involved, among which health services are at the forefront. This current community case study details a specific research-practice partnership strategy—led in Brescia (Italy) in 2023 by the Association of volunteer doctors “Un Medico x Te” (A doctor for you) and the Research Center on Family and Childhood Education (CESPEFI) of the Università Cattolica del Sacro Cuore—as an attempt to deepen the evaluation of peoples experiencing homelessness' health conditions in Brescia urban area and to promote best practices in granting population experiencing homelessness sustainable health-care approaches.MethodIn phase 1, since chronic liver diseases are very common in people experiencing homelessness, to investigate the presence of these pathologies, the Association “Un Medico x Te” carried out a preliminary observational retrospective echocardiographic cohort study in the population experiencing homelessness hosted in Brescia's housing services. In phase 2, CESPEFI led a research project to investigate the way health and healthcare is conceived by the homeless population living in Brescia urban area, according to the ethnographic methodological framework. Qualitative data were coded to explore emerging themes concerning the best practices to approach the population experiencing homelessness and to grant them appropriate care. At the end of the process internal guidelines were drawn up, based on greater attention to the relationship between doctors and patients experiencing homelessness and to the sustainability of the care-process.ResultsChronic hepatic diseases were more common and severe in people experiencing homelessness than general population and it was related to the duration of the homeless condition. Taking care of the particular aspects of the relationships between doctors and patients experiencing homelessness made clinical research and health care more effective.DiscussionThis study demonstrates that a multi-disciplinary approach is strategic in order to respond to such a complex phenomenon as homelessness is; not-adopting a multidisciplinary approach may itself represent an additional mechanism of exclusion. Further studies are needed to explore innovative strategies to better face the problem of how: 1) to approach patients experiencing homelessness and 2) to implement appropriate medical assistance

SUNNY-CP : a Sequential CP Portfolio Solver

International audienceThe Constraint Programming (CP) paradigm allows to model and solve Constraint Satisfaction / Optimization Problems (CSPs / COPs). A CP Portfolio Solver is a particular constraint solver that takes advantage of a portfolio of different CP solvers in order to solve a given problem by properly exploiting Algorithm Selection techniques. In this work we present sunny-cp: a CP portfolio for solving both CSPs and COPs that turned out to be competitive also in the MiniZinc Challenge, the reference competition for CP solvers

Portfolio Approaches for Constraint Optimization Problems

International audienceWithin the Constraints Satisfiability Problems (CSP) context, a methodology that has proved to be particularly performant consists in using a portfolio of different constraint solvers. Nevertheless, comparatively few studies and investigations has been done in the world of Constraint Optimization Problems (COP). In this work, we provide a generalization to COP as well as an empirical evaluation of different state of the art existing CSP portfolio approaches properly adapted to deal with COP. Experimental results confirm the effectiveness of portfolios even in the optimization field, and could give rise to some interesting future research

Sequential Time Splitting and Bounds Communication for a Portfolio of Optimization Solvers

Scheduling a subset of solvers belonging to a given portfolio has proven to be a good strategy when solving Constraint Satisfaction Problems (CSPs). In this paper, we show that this approach can also be effective for Constraint Optimization Problems (COPs). Unlike CSPs, sequential execution of optimization solvers can communicate information in the form of bounds to improve the performance of the following solvers. We provide a hybrid and flexible portfolio approach that combines static and dynamic time splitting for solving a given COP. Empirical evaluations show the approach is promising and sometimes even able to outperform the best solver of the porfolio. \ua9 2014 Springer International Publishing Switzerland

JSetL User's Manual - Version 2.3

This manual describes JSetL 2.3, a Java library that offers a number of facilities to support declarative programming like those usually found in constraint logic programming languages: logical variables, list and set data structures (possibly partially specfied), unfication, constraint solving over integers and sets, nondeterminism. JSetL is intended to be used as a general-purpose tool, not devoted to any specific application. The manual describes all the features of JSetL and it shows, through simple examples, how to use them. JSetL has been developed at the Department of Mathematics of the University of Parma (Italy). It is completely written in Java. The full Java code of the JSetL library, along with sample programs and related material, is available at the JSetL WEB page http://cmt.math.unipr.it/jsetl.html

Propagating Regular membership with dashed strings

Using dashed strings is an approach recently introduced in Constraint Programming (CP) to represent the domain of string variables, when solving combinatorial problems with string constraints. One of the most important string constraints is that of regular membership: regular (x, R) imposes string x to be a member of the regular language defined by automaton R. The regular constraint is useful for specifying complex constraints on fixed length finite sequences, and regularly appears in CP models. Dealing with regular is also desirable in software testing and verification, because regular expressions are often used in modern programming languages for pattern matching. In this paper, we define a regular propagator for dashed string solvers. We show that this propagator, implemented in the G-Strings solver, is substantially better than the current state-of-the-art. We also demonstrate that many regular constraints appearing in string solving benchmarks can actually be tackled by dashed strings solvers without explicitly using REGULAR