KLAIM: A Kernel Language for Agents Interaction and Mobility

We investigate the issue of designing a kernel programming language for mobile computing and describe KLAIM, a language that supports a programming paradigm where processes, like data, can be moved from one computing environment to another. The language consists of a core Linda with multiple tuple spaces and of a set of operators for building processes. KLAIM naturally supports programming with explicit localities. Localities are first-class data (they can be manipulated like any other data), but the language provides coordination mechanisms to control the interaction protocols among located processes. The formal operational semantics is useful for discussing the design of the language and provides guidelines for implementations. KLAIM is equipped with a type system that statically checks access rights violations of mobile agents. Types are used to describe the intentions (read, write, execute, etc.) of processes in relation to the various localities. The type system is used to determine the operations that processes want to perform at each locality, and to check whether they comply with the declared intentions and whether they have the necessary rights to perform the intended operations at the specific localities. Via a series of examples, we show that many mobile code programming paradigms can be naturally implemented in our kernel language. We also present a prototype implementaton of KLAIM in Java

Effects of four Fusarium toxins (fumonisin B(1), alpha-zearalenol, nivalenol and deoxynivalenol) on porcine whole-blood cellular proliferation.

The in vitro effects of four Fusarium toxins, fumonisin B1 (FB1), a-zearalenol (a-ZEA), nivalenol (NIV) and deoxynivalenol (DON), on mitogen-induced cell proliferation were determined in swine whole-blood cultures. Considering the lack of sufficient toxicological data both on single and in combination effects, in vitro studies may contribute to risk assessment of these toxins. Incubation with increasing concentrations of FB1 did not produce any consequence on proliferation; in contrast a-ZEA, NIV and DON showed an inhibitory effect. Dose–response curves for each mycotoxin were generated. NIV was found to be the most potent toxin followed by DON and a-ZEA. The effects of both FB1 þ a-ZEA and NIVþ DON mixtures were also analysed to investigate possible interactions. The results indicated that combination of FB1þ a-ZEA produces a synergistic inhibition of porcine cell proliferation; whereas there is no interaction between DON and NIV on porcine wholeblood proliferation, at tested concentrations

Mobile Applications in X-KLAIM

Networking has turned computers from isolated data processors into powerful communication and elaboration devices, called global computers; an illustrative example is the World–Wide Web. Global computers are rapidly evolving towards programmability. The new scenario has called for new programming languages and paradigms centered around the notions of mobility and location awareness. In this paper, we briefly present X-KLAIM, an experimental programming language for global computers, and show a few programming examples

A Nonsmooth Maximum Principle for Optimal Control Problems with State and Mixed Constraints-Convex Case

Here we derive a nonsmooth maximum principle for optimal control problems with both state and mixed constraints. Crucial to our development is a convexity assumption on the "velocity set". The approach consists of applying known penalization techniques for state constraints together with recent results for mixed constrained problems.Comment: Published in 'Discrete and Continuous Dynamical Systems, Vol. 2011, pp. 174-18

Local quantum thermal susceptibility

Thermodynamics relies on the possibility to describe systems composed of a large number of constituents in terms of few macroscopic variables. Its foundations are rooted into the paradigm of statistical mechanics, where thermal properties originate from averaging procedures which smoothen out local details. While undoubtedly successful, elegant and formally correct, this approach carries over an operational problem: what is the precision at which such variables are inferred, when technical/practical limitations restrict our capabilities to local probing? Here we introduce the local quantum thermal susceptibility, a quantifier for the best achievable accuracy for temperature estimation via local measurements. Our method relies on basic concepts of quantum estimation theory, providing an operative strategy to address the local thermal response of arbitrary quantum systems at equilibrium. At low temperatures it highlights the local distinguishability of the ground state from the excited sub-manifolds, thus providing a method to locate quantum phase transitions.Comment: 9 pages, 9 figures; supplemental material (2 pages). Substantial change

Granular flow through an aperture: influence of the packing fraction

For the last 50 years, the flow of a granular material through an aperture has been intensely studied in gravity-driven vertical systems (e.g. silos and hoppers). Nevertheless, in many industrial applications, grains are horizontally transported at constant velocity, lying on conveyor belts or floating on the surface of flowing liquids. Unlike fluid flows, that are controlled by the pressure, granular flow is not sensitive to the local pressure but rather to the local velocity of the grains at the outlet. We can also expect the flow rate to depend on the local density of the grains. Indeed, vertical systems are packed in dense configurations by gravity but, in contrast, in horizontal systems the density can take a large range of values, potentially very small, which may significantly alter the flow rate. In the present article, we study, for different initial packing fractions, the discharge through an orifice of monodisperse grains driven at constant velocity by a horizontal conveyor belt. We report how, during the discharge, the packing fraction is modified by the presence of the outlet and we analyze how changes in the packing fraction induce variations in the flow rate. We observe that variations of packing fraction do not affect the velocity of the grains at the outlet and, therefore, we establish that flow-rate variations are directly related to changes in the packing fraction

The Equilibrium Dynamics for an Endogeneous Bid-Ask Spread in a Monopolistic financial Market

This paper presents an endogeneous model for the stochastic dynamics of the bid-ask spread of prices of nancial assets. The model is derived introducing an intermediary and inventory costs in the setting of equilibrium financial markets as described by Platen and Rebolledo (1996)Bid-ask spread; intermediary; dynamic equilibrium