236 research outputs found
A quantum computational semantics for epistemic logical operators. Part I: epistemic structures
Some critical open problems of epistemic logics can be investigated in the framework
of a quantum computational approach. The basic idea is to interpret sentences like
“Alice knows that Bob does not understand that π is irrational” as pieces of quantum information
(generally represented by density operators of convenient Hilbert spaces). Logical
epistemic operators (to understand, to know. . .) are dealt with as (generally irreversible)
quantum operations, which are, in a sense, similar to measurement-procedures. This approach
permits us to model some characteristic epistemic processes, that concern both human
and artificial intelligence. For instance, the operation of “memorizing and retrieving
information” can be formally represented, in this framework, by using a quantum teleportation
phenomenon
Designing assistive technology for getting more independence for blind people when performing everyday tasks: an auditory-based tool as a case study
Everyday activities and tasks should in theory be easily carried by everyone, including the blind. Information and Communication Technology (ICT) has been widely used for supporting solutions. However, the solutions can be problematic for the visually impaired since familiarity with digital devices is often required. Or, indeed the procedure can be perceived as fiddly or impractical particularly for repetitive tasks due to the number/type of steps required to complete the task. This paper introduces a simple audio-based tool aimed at supporting visually-impaired people in the seemingly simple activity of checking whether the light in a room is on or off. It is an example of potential low tech devices that can be designed without the need for specific skills or knowledge by the user, and that functions in a practical way. In this context, we discuss the main issues and considerations for totally blind users in identifying whether a light is switched on. The proposed prototype is based on a simple circuit and a form of auditory feedback which informs the user whether they are switching on or off the light. Two prototypes have been designed and built for two different kinds of installation. For the subsequent second prototype, three different versions are proposed to provide a blind person with further support in easily identifying the light status at home. The new design includes enhanced auditory feedback and modifications to the dimensions. The evaluation conducted by involving various groups of end-users revealed the usefulness of the proposed tool. In addition, a survey conducted with 100 visually-impaired people reported the limitations and difficulties encountered by the blind in using existing devices. Moreover, the study revealed the interest from 94% of the participants for a potential (new) basic tool integrable with the existing lighting system. This study gives a contribution in the ambient intelligence field by (1) showing how an auditory-based tool can be used to support totally blind people to check the lights in an autonomous and relatively simple way; (2) proposing an idea that can be exploited in other application cases that use light feedback; and (3) proposing seven potential recommendations for designing assistive technology tools and common everyday devices, based on information gathered from the online survey
Enriquecimiento cognoscitivo: el hombre visto como sistema abierto
Texto sobre las aportaciones y los beneficios de la perspectiva psicolĂłgica del enriquecimiento cognoscitivo para la intervenciĂłn educativa y terapĂ©utica con personas que demuestran desempeño retardado y otros tipos de desviaciĂłn emocional o conductual. Se incluye tambiĂ©n texto sobre el Primer Coloquio Internacional de PsicologĂa Comunitaria y la DĂ©cima Semana de PsicologĂa en el ITESO
Competition of the connectivity with the local and the global order in polymer melts and crystals
The competition between the connectivity and the local or global order in
model fully-flexible chain molecules is investigated by molecular-dynamics
simulations. States with both missing (melts) and high (crystal) global order
are considered. Local order is characterized within the first coordination
shell (FCS) of a tagged monomer and found to be lower than in atomic systems in
both melt and crystal. The role played by the bonds linking the tagged monomer
to FCS monomers (radial bonds), and the bonds linking two FCS monomers (shell
bonds) is investigated. The detailed analysis in terms of Steinhardt's
orientation order parameters Q_l (l = 2 - 10) reveals that increasing the
number of shell bonds decreases the FCS order in both melt and crystal.
Differently, the FCS arrangements organize the radial bonds. Even if the
molecular chains are fully flexible, the distribution of the angle formed by
adjacent radial bonds exhibits sharp contributions at the characteristic angles
{\theta} = 70{\deg}, 122{\deg}, 180{\deg}. The fractions of adjacent radial
bonds with {\theta} = 122{\deg}, 180{\deg} are enhanced by the global order of
the crystal, whereas the fraction with 70{\deg} < {\theta} < 110{\deg} is
nearly unaffected by the crystallization. Kink defects, i.e. large lateral
displacements of the chains, are evidenced in the crystalline state.Comment: J. Chem. Phys. in pres
A first-order epistemic quantum computational semantics with relativistic-like epistemic effects
Quantum computation has suggested new forms of quantum logic, called quantum computational logics. In these logics well-formed formulas are supposed to denote pieces of quantum information: possible pure states of quantum systems that can store the information in question. At the same time, the logical connectives are interpreted as quantum logical gates: unitary operators that process quantum information in a reversible way, giving rise to quantum circuits. Quantum computational logics have been mainly studied as sentential logics (whose alphabet consists of atomic sentences and of logical connectives). In this article we propose a semantic characterization for a first-order epistemic quantum computational logic, whose language can express sentences like "Alice knows that everybody knows that she is pretty". One can prove that (unlike the case of logical connectives) both quantifiers and epistemic operators cannot be generally represented as (reversible) quantum logical gates. The "act of knowing" and the use of universal (or existential) assertions seem to involve some irreversible "theoretic jumps", which are similar to quantum measurements. Since all epistemic agents are characterized by specific epistemic domains (which contain all pieces of information accessible to them), the unrealistic phenomenon of logical omniscience is here avoided: knowing a given sentence does not imply knowing all its logical consequences
Coincident correlation between vibrational dynamics and primary relaxation of polymers with strong or weak johari-goldstein relaxation
The correlation between the vibrational dynamics, as sensed by the Debye-Waller factor, and the primary relaxation in the presence of secondary Johari-Goldstein (JG) relaxation, has been investigated through molecular dynamics simulations. Two melts of polymer chains with different bond length, resulting in rather different strength of the JG relaxation are studied. We focus on the bond-orientation correlation function, exhibiting higher JG sensitivity with respect to alternatives provided by torsional autocorrelation function and intermediate scattering function. We find that, even if changing the bond length alters both the strength and the relaxation time of the JG relaxation, it leaves unaffected the correlation between the vibrational dynamics and the primary relaxation. The finding is in harmony with previous studies reporting that numerical models not showing secondary relaxations exhibit striking agreement with experimental data of polymers also where the presence of JG relaxation is known
Glassforming Liquids, Amorphous and Semicrystalline Polymers: Exploring their Energy Landscape and Dynamical Heterogeneity by Multi-frequency High-Field EPR
We review past and recent work carried out on viscous liquids, amorphous and semicrystalline polymers by multifrequency high-field electron paramagnetic resonance (HF-EPR) facility in Pisa. The emphasis is on the enhanced ability to provide fine details of the reorientation process of the paramagnetic guest, the spin probe, revealing features driving the dynamics of the host system, including the energy-barrier distribution of glassy polymers, the dynamical heterogeneity of semicrystalline polymers, and the dynamical changes occurring at the critical temperature predicted by the ideal mode-coupling theory
Glassforming Liquids, Amorphous and Semicrystalline Polymers: Exploring their Energy Landscape and Dynamical Heterogeneity by Multi-frequency High-Field EPR
AbstractWe review past and recent work carried out on viscous liquids, amorphous and semicrystalline polymers by multifrequency high-field electron paramagnetic resonance (HF-EPR) facility in Pisa. The emphasis is on the enhanced ability to provide fine details of the reorientation process of the paramagnetic guest, the spin probe, revealing features driving the dynamics of the host system, including the energy-barrier distribution of glassy polymers, the dynamical heterogeneity of semicrystalline polymers, and the dynamical changes occurring at the critical temperature predicted by the ideal mode-coupling theory
A study of the deep structure of the energy landscape of glassy polystyrene: the exponential distribution of the energy-barriers revealed by high-field Electron Spin Resonance spectroscopy
The reorientation of one small paramagnetic molecule (spin probe) in glassy
polystyrene (PS) is studied by high-field Electron Spin Resonance spectroscopy
at two different Larmor frequencies (190 and 285 GHz). The exponential
distribution of the energy-barriers for the rotational motion of the spin probe
is unambigously evidenced at both 240K and 270K. The same shape for the
distribution of the energy-barriers of PS was evidenced by the master curves
provided by previous mechanical and light scattering studies. The breadth of
the energy-barriers distribution of the spin probe is in the range of the
estimates of the breadth of the PS energy-barriers distribution. The evidence
that the deep structure of the energy landscape of PS exhibits the exponential
shape of the energy-barriers distribution agrees with results from
extreme-value statistics and the trap model by Bouchaud and coworkers.Comment: Final version in press as Letter to the Editor on J.Phys.:Condensed
Matter. Changes in bol
Ceiba speciosa (A. St.-Hil.) seeds oil: Fatty acids profiling by GC-MS and NMR and bioactivity
This study aimed to evaluate the chemical composition by gas chromatography-mass spectrometry (GC-MS) and Nuclear Magnetic Resonance (NMR) analyses, the antioxidant activities evaluated by different in vitro assays namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,20-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), Ferric Reducing Ability Power (FRAP), and β-carotene bleaching tests, and the inhibitory effects of enzymes linked to obesity (lipase, α-amylase, and α-glucosidase) of fixed seed oil of Ceiba speciosa (A. St.-Hil.). Fourteen compounds were identified. Linoleic acid (28.22%) was the most abundant followed by palmitic acid (19.56%). Malvalic acid (16.15%), sterculic acid (11.11%), and dihydrosterculic acid (2.74%) were also detected. C. speciosa fixed oil exerted a promising ABTS radicals scavenging activity with an IC50 value of 10.21 µg/mL, whereas an IC50 of 77.44 µg/mL against DPPH+ radicals was found. C. speciosa fixed oil inhibited lipase with an IC50 value of 127.57 µg/mL. The present investigation confirmed the functional properties of C. speciosa fixed oil, and proposes its use as valuable source of bioactive constituents
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