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21.
Giampiero Sacchetti Paola Pittia Manuela Biserni Gian G. Pinnavaia & Marco D. Rosa 《International Journal of Food Science & Technology》2003,38(2):135-143
Summary Ready‐to‐eat breakfast cereals immersed in milk undergo undesirable changes in texture because of sudden moisture uptake. The textural changes are ascribable to a plasticizing effect of water, which modifies the mechanical strength of products by softening the starch/protein matrix. In this work, some textural parameters of different cereal flakes were derived from the force–displacement curves monitored during 300 s of immersion in milk. Hardness loss, deformability increment and changes in the force–displacement curve profile were calculated and plotted against soaking time. The application of a sugar coating process to a model cereal flake increased the initial product hardness and improved the preservation of the textural parameters during immersion. The Peleg model closely fitted the experimental data, with regression coefficients from 0.967 to 0.999. 相似文献
22.
Gian Piero Zarri 《Artificial Intelligence and Law》2007,15(3):251-279
An application of Narrative Knowledge Representation Language (NKRL) techniques on (declassified) ‘terrorism in Southern Philippines’
documents has been carried out in the context of the IST Parmenides project. This paper describes some aspects of this work:
it is our belief, in fact, that the Knowledge Representation techniques and the Intelligent Information Retrieval tools used
in this experiment can be of some interest also in an ‘Ontological Modelling of Legal Events and Legal Reasoning’ context. 相似文献
23.
The regulation of programmed cell death in the developing nervous system involves target-derived survival factors, afferent synaptic activity, and hormone- and cytokine-dependent signaling. Cultured immature cerebellar granule neurons die by apoptosis within several days in vitro unless maintained in depolarizing (high) concentrations of potassium (25 mM K+). Here we report that transforming growth factors (TGF)-beta1, -beta2, and -beta3 accelerate apoptosis of these neurons when maintained in physiological (low) K+ medium (5mM K+) as assessed by measures of viability, quantitative DNA fragmentation, and nuclear morphology. TGF-beta-induced apoptosis of these neurons is not blocked by CNTF and LIF, cytokines that enhance neuronal survival when applied alone, or by IGF-I, which prevents apoptosis upon potassium withdrawal. In contrast, neurons that differentiate in high K+ medium for several days in vitro acquire resistance to TGF-beta-mediated cell death. Granule neurons maintained in either low or high K+ medium produce latent, but not bioactive, TGF-beta1 and -beta2. Because neutralizing TGF-beta antibodies fail to augment survival of low K+ neurons, the cerebellar neurons are apparently unable to activate latent TGF-beta. Thus, apoptosis of low K+ neurons is not attributable to endogenous production of TGF-beta. Taken together, our data suggest that TGF-beta may limit the expansion of postmitotic neuronal precursor populations by promoting their apoptosis but may support survival of those neurons that have maturated, differentiated, and established supportive synaptic connectivity. 相似文献
24.
Lucia RussoErasmo Mancusi Pier Luca MaffettoneSilvestro Crescitelli 《Chemical engineering science》2002,57(24):5065-5082
In this work, we discuss how periodic forcing may induce symmetry properties into mathematical models of chemical reactors. We define a class of reactors subjected to discontinuous periodic forcing, and show that all the reactors belonging to this class have spatio-temporal symmetry. This symmetry and its influence on the possible bifurcation scenarios are discussed. The bifurcation analysis is carried out with suitable discrete systems that exploit a property of the Poincaré map. In fact, it is shown that the spatio-temporal symmetry induced by the forcing makes the Poincaré map of the continuous system an iterate of another map. On this basis, a technique to implement parameter continuation methods is proposed. With such a technique, it is also possible to characterize symmetric and nonsymmetric regimes and unstable limit sets otherwise undetected with “bruteforce” approaches. Examples for reverseflow reactors and networks of n-reactors with periodically switched feed and discharge positions are presented. 相似文献
25.
Luca Scardovi Marco Baglietto Thomas Parisini 《Neural Networks, IEEE Transactions on》2007,18(4):1172-1184
In this paper, we consider the problem of actively providing an estimate of the state of a stochastic dynamic system over a (possibly long) finite time horizon. The active estimation problem (AEP) is formulated as a stochastic optimal control one, in which the minimization of a suitable uncertainty measure is carried out. Toward this end, the use of the Renyi entropy as an information measure is proposed and motivated. A neural control scheme, based on the application of the extended Ritz method (ERIM) and on the use of a Gaussian sum filter (GSF), is then presented. Simulation results show the effectiveness of the proposed approach. 相似文献
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In this paper, the authors propose two modeling procedures for wind speed simulation. These procedures could be implemented on the structure of a wind turbine simulator during studies concerning stand-alone or hybrid wind systems. The evolution of a horizontal wind speed has been synthesized taking into account two components. The medium- and long-term component is described by a power spectrum associated to a specific site. The turbulence component is assumed to be dependent on the medium- and long-term wind speed evolution. It is considered as a nonstationary process. Two simulation methods for this component, using rational and nonrational filters are proposed. In both procedures, the turbulence model is defined by two parameters, which are either obtained experimentally, or adopted a priori, according to information from the considered site. Numerical results and implementation aspects are also discussed. 相似文献
29.
Timing and causality in process algebra 总被引:4,自引:0,他引:4
There has been considerable controversy in concurrency theory between the ‘interleaving’ and ‘true concurrency’ schools.
The former school advocates associating a transition system with a process which captures concurrent execution via the interleaving
of occurrences; the latter adopts more complex semantic structures to avoid reducing concurrency to interleaving.
In this paper we show that the two approaches are not irreconcilable. We define a timed process algebra where occurrences
are associated with intervals of time, and give it a transition system semantics. This semantics has many of the advantages
of the interleaving approach; the algebra admits an expansion theorem, and bisimulation semantics can be used as usual. Our
transition systems, however, incorporate timing information, and this enables us to express concurrency: merely adding timing
appropriately generalises transition systems to asynchronous transition systems, showing that time gives a link between true
concurrency and interleaving. Moreover, we can provide a complete axiomatisation of bisimulation for our algebra; a result
that is often problematic in a timed setting.
Another advantage of incorporating timing information into the calculus is that it allows a particularly simple definition
of action refinement; this we present. The paper concludes with a comparison of the equivalence we present with those in the
literature, and an example system specification in our formalism.
Received December 20, 1993/February 23, 1995 相似文献
30.
Condia Josie E. Rodriguez Narducci Pierpaolo Sonza Reorda Matteo Sterpone Luca 《The Journal of supercomputing》2021,77(10):11625-11642
The Journal of Supercomputing - General-purpose graphics processing units (GPGPUs) are extensively used in high-performance computing. However, it is well known that these devices’... 相似文献