Causality and replication in concurrent processes

The replication operator was introduced by Milner for obtaining a simplified description of recursive processes. The standard interleaving semantics denotes the replication of a process P, written !P, a shorthand for its unbound parallel composition, operationally equivalent to the process P | P | …, with P repeated as many times as needed. Albeit the replication mechanism has become increasingly popular, investigations on its causal semantics has been scarce. In fact, the correspondence between replication and unbound parallelism makes it difficult to recover basic properties usually associated with these semantics, such as the so-called concurrency diamond. In this paper we consider the interleaving semantics for the operator proposed by Sangiorgi and Walker, and we show how to refine it in order to capture causality. Furthermore, we prove it coincident with the standard causal semantics for recursive process studied in the literature, for processes defined by means of constant invocations

Model checking usage policies

We study usage automata, a formal model for specifying policies on the usage of resources. Usage automata extend finite state automata with some additional features, parameters and guards, that improve their expressivity. We show that usage automata are expressive enough to model policies of real-world applications. We discuss their expressive power, and we prove that the problem of telling whether a computation complies with a usage policy is decidable. The main contribution of this paper is a model checking technique for usage automata. The model is that of usages, i.e. basic processes that describe the possible patterns of resource access and creation. In spite of the model having infinite states, because of recursion and resource creation, we devise a polynomial-time model checking technique for deciding when a usage complies with a usage policy

Indefinites and free choice:When the past matters

Indefinites display a great functional variety and they give rise to different pragmatic effects. We focus on free choice indefinites and in particular on the Italian qualsiasi. Our aim is to reconstruct the grammaticalization path of this item and understand how diachronic data might shed some light on existing semantic theories of free choice. We employ corpus-based tools to build a database containing occurrences of qualsiasi from its origin and early forms to its current usage. We show that qualsiasi emerged from a particular unconditional construction and we outline the different stages which led to its grammaticalization. We analyze the compatibility of our diachronic study with formal accounts of free choice inferences, with a focus on Alternative Semantics analyses for indefinite pronouns and so-called grammatical theories of free choice. Our work shows that an integration between formal semantics and historical linguistics is fruitful and worth pursuing

Selection criteria and robust optimization of a traction PM-Assisted Synchronous Reluctance motor

In the coming years, the electrification and the deployment of the electric motors in the urban transports will become a more and more widespread reality. The optimization stage of the electric motors usually does not consider in detail the real driving conditions of the car in which the motor is installed. It follows that the actual motor performance in operating points, particularly as regards the torque ripple and the efficiency, might be worse than expected. A robust solution is a required target. This paper deals with the design and optimization of a high-speed permanent-magnet-assisted synchronous reluctance motor for traction applications, taking into account both city and highway driving cycles. A procedure is employed in order to evaluate the most representative operating points, which have to be considered when a global optimization is required. An analysis of the solution robustness has been performed. Both results and advantages of the adopted methodology are highlighted

Control-flow flattening preserves the constant-time policy

Obfuscating compilers protect a software by obscuring its meaning and impeding the reconstruction of its original source code. The typical concern when defining such compilers is their robustness against reverse engineering and the performance of the produced code. Little work has been done in studying whether the security properties of a program are preserved under obfuscation. In this paper we start addressing this problem: we consider control-flow flattening, a popular obfuscation technique used in industrial compilers, and a specific security policy, namely constant-time. We prove that this obfuscation preserves the policy, i.e., that every program satisfying the policy still does after the transformation

Smart transportation systems (STSs) in critical conditions

In the context of smart transportation systems (STSs) in smart cities, the use of applications that can help in case of critical conditions is a key point. Examples of critical conditions may be natural-disaster events such as earthquakes, hurricanes, floods, and manmade ones such as terrorist attacks and toxic waste spills. Disaster events are often combined with the destruction of the local telecommunication infrastructure, if any, and this implies real problems to the rescue operations.The quick deployment of a telecommunication infrastructure is essential for emergency and safety operations as well as the rapid network reconfigurability, the availability of open source software, the efficient interoperability, and the scalability of the technological solutions. The topic is very hot and many research groups are focusing on these issues. Consequently, the deployment of a smart network is fundamental. It is needed to support both applications that can tolerate delays and applications requiring dedicated resources for real-time services such as traffic alert messages, and public safety messages. The guarantee of quality of service (QoS) for such applications is a key requirement.In this chapter we will analyze the principal issues of the networking aspects and will propose a solution mainly based on software defined networking (SDN). We will evaluate the benefit of such paradigm in the mentioned context focusing on the incremental deployment of such solution in the existing metropolitan networks and we will design a "QoS App" able to manage the quality of service on top of the SDN controller

A mass spectrometric study on tannin degradation within dyed woolen yarns

Natural tannins from various plants have been used throughout human history in textile dyeing, often as mordant dyes. The ageing behavior of these dyes is a challenge in conservation science, requiring a thorough knowledge of the textile–mordant-dye system. In this work, we analyzed reference wool yarns dyed with natural tannins from oak gallnuts, walnut (Juglans regia), and catechu (Acacia catechu), after artificial ageing. To gain insights on the composition of the dyestuffs and on how they aged, an analytical procedure based on extraction with Na2EDTA/DMF (ethylenediaminetetraacetic acid/dimethylformamide) and high-performance liquid chromatography (HPLC) analysis using high-resolution mass spectrometry detection was used. Since conventional reversed-phase (RP) columns usually show poor retention efficiency of highly polar compounds such as tannins, an RP-amide embedded polar group stationary phase was used to achieve optimal retention of the most polar compounds. Tannins from oak gallnuts showed little degradation after ageing, while a significant increase in the content of hydroxybenzoic acids was observed for tannins from walnut and catechu. Finally, the analytical procedure was applied to characterize the tannin dyes in historical tapestries from the 15th to 16th century, and the results were discussed in comparison with the reference yarns