Timed Multiparty Session Types

We propose a typing theory, based on multiparty session types, for modular verification of real-time choreographic interactions. To model real-time implementations, we introduce a simple calculus with delays and a decidable static proof system. The proof system ensures type safety and time-error freedom, namely processes respect the prescribed timing and causalities between interactions. A decidable condition on timed global types guarantees time-progress for validated processes with delays, and gives a sound and complete characterisation of a new class of CTAs with general topologies that enjoys progress and liveness

On the Behaviour of General-Purpose Applications on Cloud Storages

Managing data over cloud infrastructures raises novel challenges with respect to existing and well studied approaches such as ACID and long running transactions. One of the main requirements is to provide availability and partition tolerance in a scenario with replicas and distributed control. This comes at the price of a weaker consistency, usually called eventual consistency. These weak memory models have proved to be suitable in a number of scenarios, such as the analysis of large data with Map-Reduce. However, due to the widespread availability of cloud infrastructures, weak storages are used not only by specialised applications but also by general purpose applications. We provide a formal approach, based on process calculi, to reason about the behaviour of programs that rely on cloud stores. For instance, one can check that the composition of a process with a cloud store ensures `strong' properties through a wise usage of asynchronous message-passing

School Climate: Parents\u2019, Students\u2019 And Teachers\u2019 Perceptions

Because of the importance of individual perceptions, schools often assess how students or teachers or parents feel about their school, and school climate has often been associated with improved school achievement, but rarely they take into account all these \u201cactors\u201d at the same time. The main aim of this work is to compare the results obtained in a population study on school climate that involves students, parents, teachers and non-teaching staff. In this paper, we will present the results of parents\u2019, students\u2019, teachers\u2019 and no-teacher personnel's perception. We have administered 13,500 structured questionnaires addressed to students, parents, teachers, educational assistance personnel, involved in the four orders of schools (Pre-school, Elementary, Middle, High) of the province of Bolzano. Parental permission was obtained for young people. The present study has been conducted in the province of Bolzano, northern Italy, between January and April 2012. A School Climate Perception Questionnaire (SCPQ), that can be completed in 10 minutes, has been developed to assess environments and climate of all Italian language schools. In order to determine the interrelationships among the questionnaire items, a Principal-Axis Factor Analysis was performed. The final scale was used for Confirmatory Factor Analysis that was done to assess its construct validity. We will present the results regarding the school climate perceptions of teachers, parents and students and their comparison

Monitoring Networks through Multiparty Session Types

In large-scale distributed infrastructures, applications are realised through communications among distributed components. The need for methods for assuring safe interactions in such environments is recognized, however the existing frameworks, relying on centralised verification or restricted specification methods, have limited applicability. This paper proposes a new theory of monitored π-calculus with dynamic usage of multiparty session types (MPST), offering a rigorous foundation for safety assurance of distributed components which asynchronously communicate through multiparty sessions. Our theory establishes a framework for semantically precise decentralised run-time enforcement and provides reasoning principles over monitored distributed applications, which complement existing static analysis techniques. We introduce asynchrony through the means of explicit routers and global queues, and propose novel equivalences between networks, that capture the notion of interface equivalence, i.e. equating networks offering the same services to a user. We illustrate our static-dynamic analysis system with an ATM protocol as a running example and justify our theory with results: satisfaction equivalence, local/global safety and transparency, and session fidelity

The Sensoria Approach Applied to the Finance Case Study

This chapter provides an effective implementation of (part of) the Sensoria approach, specifically modelling and formal analysis of service-oriented software based on mathematically founded techniques. The ‘Finance case study’ is used as a test bed for demonstrating the feasibility and effectiveness of the use of the process calculus COWS and some of its related analysis techniques and tools. In particular, we report the results of an application of a temporal logic and its model checker for expressing and checking functional properties of services and a type system for guaranteeing confidentiality properties of services

The Reversible Temporal Process Language

Reversible debuggers help programmers to quickly find the causes of misbehaviours in concurrent programs. These debuggers can be founded on the well-studied theory of causal-consistent reversibility, which allows one to undo any action provided that its consequences are undone beforehand. Till now, causal-consistent reversibility never considered time, a key aspect in real world applications. Here, we study the interplay between reversibility and time in concurrent systems via a process algebra. The Temporal Process Language (TPL) by Hennessy and Regan is a well-understood extension of CCS with discrete-time and a timeout operator. We define revTPL, a reversible extension of TPL, and we show that it satisfies the properties expected from a causal-consistent reversible calculus. We show that, alternatively, revTPL can be interpreted as an extension of reversible CCS with time

Real-time optical manipulation of cardiac conduction in intact hearts

Optogenetics has provided new insights in cardiovascular research, leading to new methods for cardiac pacing, resynchronization therapy and cardioversion. Although these interventions have clearly demonstrated the feasibility of cardiac manipulation, current optical stimulation strategies do not take into account cardiac wave dynamics in real time. Here, we developed an all‐optical platform complemented by integrated, newly developed software to monitor and control electrical activity in intact mouse hearts. The system combined a wide‐field mesoscope with a digital projector for optogenetic activation. Cardiac functionality could be manipulated either in free‐run mode with submillisecond temporal resolution or in a closed‐loop fashion: a tailored hardware and software platform allowed real‐time intervention capable of reacting within 2 ms. The methodology was applied to restore normal electrical activity after atrioventricular block, by triggering the ventricle in response to optically mapped atrial activity with appropriate timing. Real‐time intraventricular manipulation of the propagating electrical wavefront was also demonstrated, opening the prospect for real‐time resynchronization therapy and cardiac defibrillation. Furthermore, the closed‐loop approach was applied to simulate a re‐entrant circuit across the ventricle demonstrating the capability of our system to manipulate heart conduction with high versatility even in arrhythmogenic conditions. The development of this innovative optical methodology provides the first proof‐of‐concept that a real‐time optically based stimulation can control cardiac rhythm in normal and abnormal conditions, promising a new approach for the investigation of the (patho)physiology of the heart

Canopy Changes of Brachiaria Managed Under Continuous Stocking in the Dry-Water Transition

Pasture supplementation is an alternative to take advantage of the forage mass deferred in the rainy season and maintain or provide weight gain in periods of rain absence. The objective was to compare the structural characteristics, mass production, density and population dynamics of tillers of Urochloa brizantha cv. ‘Paiaguas’ and U. spp. cv. ‘Convert’ under fixed and continuous stocking with steers supplemented in the trough or on the ground in the water/dry transition period. The experiment was carried out at Jatai Federal University, from March to June, in a completely randomized design and a 2x2 factorial scheme, using six paddocks/treatment. The completely randomized design was adopted and variance analysis was performed with software SAS following the GLM procedure, were compared using repeated-measures. There was a significant interaction between Brachiaria and the method of supplementation for basal, aerial, and total tiller density. Convert had an average of 551 basal and 577 total tiller/m2. Paiaguas grass presented higher tiller density (1,03 vs. 582 tiller/m2) and higher tiller birth rate (12.92 vs. 9.14%) than Convert. No significant difference was observed between brachiarias. The average height of Paiaguas was 62.34 and 50.70 cm for Convert. The average height was 57.83 and on the ground it was 54.90 cm. Supplementation offer method changed Paiaguas canopy. The Convert showed higher leaf and dead mass production but lower weeds despite its smaller tillering