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

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

Revealing the trajectories of KLAIM tuples, statically

Klaim (Kernel Language for Agents Interaction and Mobility) has been devised to design distributed applications composed by many components deployed over the nodes of a distributed infrastructure and to offer programmers primitive constructs for communicating, distributing and retrieving data. Data could be sensitive and some nodes could not be secure. As a consequence it is important to track data in their traversal of the network. To this aim, we propose a Control Flow Analysis that over-approximates the behaviour of Klaim processes and tracks how tuple data can move in the network

Short communication: Mid-infrared spectroscopy prediction of fine milk composition and technological properties in Italian Simmental

open4The objective of this study was to evaluate the ability of mid-infrared predictions of fine milk composition and technological traits to serve as a tool for large-scale phenotyping of the Italian Simmental population. Calibration equations accurately predicted the fatty acid profile of the milk, but we obtained moderate or poor accuracy for detailed protein composition, coagulation properties, curd yield and composition, lactoferrin, and concentration of major minerals. To evaluate the role of infrared predictions as indicator traits of fine milk composition in indirect selective breeding programs, the genetic parameters of the traits predicted using mid-infrared spectra need to be estimated.partially_openBonfatti, V; Degano, L; Menegoz, A; Carnier, PBonfatti, Valentina; Degano, Lorenzo; Menegoz, A; Carnier, Paol

Trajectory Based Market Models: Evaluation of Minmax Price Bounds

The paper studies sub and super-replication price bounds for contingent claims defined on general trajectory based market models. No prior probabilistic or topological assumptions are placed on the trajectory space which is of unrestricted cardinality. For a given option, there exists an interval bounding the set of possible fair prices; such interval exists under more general conditions than the usual no-arbitrage requirement. The paper develops a backward recursive method to evaluate the option bounds together with the associated hedging strategies; the global minmax optimization, defining the price interval, is reduced to a local minmax optimization via dynamic programming. Trajectory sets are introduced for which existing probabilistic and non-probabilistic market models are nested as particular cases. Several examples are presented, the effect of the presence of arbitrage on the price bounds is illustrated.Fil: Degano, Iván Leonardo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Sebastián E. Ferrando. Ryerson University; CanadáFil: Alfredo L, González. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentin