475 research outputs found
Belief Revision in Structured Probabilistic Argumentation
In real-world applications, knowledge bases consisting of all the information
at hand for a specific domain, along with the current state of affairs, are
bound to contain contradictory data coming from different sources, as well as
data with varying degrees of uncertainty attached. Likewise, an important
aspect of the effort associated with maintaining knowledge bases is deciding
what information is no longer useful; pieces of information (such as
intelligence reports) may be outdated, may come from sources that have recently
been discovered to be of low quality, or abundant evidence may be available
that contradicts them. In this paper, we propose a probabilistic structured
argumentation framework that arises from the extension of Presumptive
Defeasible Logic Programming (PreDeLP) with probabilistic models, and argue
that this formalism is capable of addressing the basic issues of handling
contradictory and uncertain data. Then, to address the last issue, we focus on
the study of non-prioritized belief revision operations over probabilistic
PreDeLP programs. We propose a set of rationality postulates -- based on
well-known ones developed for classical knowledge bases -- that characterize
how such operations should behave, and study a class of operators along with
theoretical relationships with the proposed postulates, including a
representation theorem stating the equivalence between this class and the class
of operators characterized by the postulates
Explicit Solution to the N-Body Calogero Problem
We solve the N-body Calogero problem, \ie N particles in 1 dimension subject
to a two-body interaction of the form \half \sum_{i,j}[ (x_i - x_j)^2 + g/
{(x_i - x_j)^2}], by constructing annihilation and creation operators of the
form , where is
a modified momentum operator obeying %!!!!!!! Heisenberg-type commutation
relations with , involving explicitly permutation operators. On the other
hand, can be interpreted as a covariant derivative
corresponding to a flat connection. The relation to fractional statistics in
1+1 dimensions and anyons in a strong magnetic field is briefly discussed.Comment: 6 p., latex, USITP-92-
Composability and Predictability for Independent Application Development, Verification and Execution
System-on-chip (SOC) design gets increasingly complex, as a growing number of applications are integrated in modern systems. Some of these applications have real-time requirements, such as a minimum throughput or a maximum latency. To reduce cost, system resources are shared between applications, making their timing behavior inter-dependent. Real-time requirements must hence be verified for all possible combinations of concurrently executing applications, which is not feasible with commonly used simulation-based techniques. This chapter addresses this problem using two complexity-reducing concepts: composability and predictability. Applications in a composable system are completely isolated and cannot affect each other’s behaviors, enabling them to be independently verified. Predictable systems, on the other hand, provide lower bounds on performance, allowing applications to be verified using formal performance analysis. Five techniques to achieve composability and/or predictability in SOC resources are presented and we explain their implementation for processors, interconnect, and memories in our platform
Discrete-time rewards model-checked
This paper presents a model-checking approach for analyzing discrete-time Markov reward models. For this purpose, the temporal logic probabilistic CTL is extended with reward constraints. This allows to formulate complex measures – involving expected as well as accumulated rewards – in a precise and succinct way. Algorithms to efficiently analyze such formulae are introduced. The approach is illustrated by model-checking a probabilistic cost model of the IPv4 zeroconf protocol for distributed address assignment in ad-hoc networks
Finite Temperature Correlators in the Schwinger Model
We discuss the correlation function of hadronic currents in the Schwinger
model at finite temperature . We explicitly construct the retarded
correlator in real time and obtain analytical results for the Euclidean
correlator on a torus. Both constructions lead to the same finite temperature
spectral function. The spatial screening lengths in the mesonic channels are
related to the dynamical meson mass and not even in
the infinite temperature limit. The relevance of our results for the finite
temperature problem in four dimensions is discussed.Comment: in LATEX, 30 pages; two figures available on request from the
authors; USITP-93-19, SUNY-NTG-43, (explanations to the figures have been
clarified
The Effects of Quantum Entropy on the Bag Constant
The effects of quantum entropy on the bag constant are studied at low
temperatures and small chemical potentials. The inclusion of the quantum
entropy of the quarks in the equation of state provides the hadronic bag with
an additional heat which causes a decrease in the effective latent heat inside
the bag. We have considered two types of baryonic bags, and
. In both cases we have found that the bag constant without the
quantum entropy almost does not change with the temperature and the quark
chemical potential. The contribution from the quantum entropy to the equation
of state clearly decreases the value of the bag constant.Comment: 7 pages, 2 figures (two parts each
A quantum mechanical description of the experiment on the observation of gravitationally bound states
Quantum states in the Earth's gravitational field were observed, when
ultra-cold neutrons fall under gravity. The experimental results can be
described by the quantum mechanical scattering model as it is presented here.
We also discuss other geometries of the experimental setup which correspond to
the absence or the reversion of gravity. Since our quantum mechanical model
describes, particularly, the experimentally realized situation of reversed
gravity quantitatively, we can practically rule out alternative explanations of
the quantum states in terms of pure confinement effects.Comment: LaTeX, 10 pages, 4 figures, v2: references adde
Energy Relaxation in Nonlinear One-Dimensional Lattices
We study energy relaxation in thermalized one-dimensional nonlinear arrays of
the Fermi-Pasta-Ulam type. The ends of the thermalized systems are placed in
contact with a zero-temperature reservoir via damping forces. Harmonic arrays
relax by sequential phonon decay into the cold reservoir, the lower frequency
modes relaxing first. The relaxation pathway for purely anharmonic arrays
involves the degradation of higher-energy nonlinear modes into lower energy
ones. The lowest energy modes are absorbed by the cold reservoir, but a small
amount of energy is persistently left behind in the array in the form of almost
stationary low-frequency localized modes. Arrays with interactions that contain
both a harmonic and an anharmonic contribution exhibit behavior that involves
the interplay of phonon modes and breather modes. At long times relaxation is
extremely slow due to the spontaneous appearance and persistence of energetic
high-frequency stationary breathers. Breather behavior is further ascertained
by explicitly injecting a localized excitation into the thermalized array and
observing the relaxation behavior
Mate discrimination among subspecies through a conserved olfactory pathway.
Communication mechanisms underlying the sexual isolation of species are poorly understood. Using four subspecies of Drosophila mojavensis as a model, we identify two behaviorally active, male-specific pheromones. One functions as a conserved male antiaphrodisiac in all subspecies and acts via gustation. The second induces female receptivity via olfaction exclusively in the two subspecies that produce it. Genetic analysis of the cognate receptor for the olfactory pheromone indicates an important role for this sensory pathway in promoting sexual isolation of subspecies, in combination with auditory signals. Unexpectedly, the peripheral sensory pathway detecting this pheromone is conserved molecularly, physiologically, and anatomically across subspecies. These observations imply that subspecies-specific behaviors arise from differential interpretation of the same peripheral cue, reminiscent of sexually conserved detection but dimorphic interpretation of male pheromones in Drosophila melanogaster. Our results reveal that, during incipient speciation, pheromone production, detection, and interpretation do not necessarily evolve in a coordinated manner
Algebra of the observables in the Calogero model and in the Chern-Simons matrix model
The algebra of observables of an N-body Calogero model is represented on the
S_N-symmetric subspace of the positive definite Fock space. We discuss some
general properties of the algebra and construct four different realizations of
the dynamical symmetry algebra of the Calogero model. Using the fact that the
minimal algebra of observables is common to the Calogero model and the finite
Chern-Simons (CS) matrix model, we extend our analysis to the CS matrix model.
We point out the algebraic similarities and distinctions of these models.Comment: 24 pages, misprints corrected, reference added, final version, to
appear in PR
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