318 research outputs found
Thermodynamics of spin systems on small-world hypergraphs
We study the thermodynamic properties of spin systems on small-world
hypergraphs, obtained by superimposing sparse Poisson random graphs with p-spin
interactions onto a one-dimensional Ising chain with nearest-neighbor
interactions. We use replica-symmetric transfer-matrix techniques to derive a
set of fixed-point equations describing the relevant order parameters and free
energy, and solve them employing population dynamics. In the special case where
the number of connections per site is of the order of the system size we are
able to solve the model analytically. In the more general case where the number
of connections is finite we determine the static and dynamic
ferromagnetic-paramagnetic transitions using population dynamics. The results
are tested against Monte-Carlo simulations.Comment: 14 pages, 7 figures; Added 2 figures. Extended result
On metastable configurations of small-world networks
We calculate the number of metastable configurations of Ising small-world
networks which are constructed upon superimposing sparse Poisson random graphs
onto a one-dimensional chain. Our solution is based on replicated
transfer-matrix techniques. We examine the denegeracy of the ground state and
we find a jump in the entropy of metastable configurations exactly at the
crossover between the small-world and the Poisson random graph structures. We
also examine the difference in entropy between metastable and all possible
configurations, for both ferromagnetic and bond-disordered long-range
couplings.Comment: 9 pages, 4 eps figure
Continuous Interaction with a Virtual Human
Attentive Speaking and Active Listening require that a Virtual Human be capable of simultaneous perception/interpretation and production of communicative behavior. A Virtual Human should be able to signal its attitude and attention while it is listening to its interaction partner, and be able to attend to its interaction partner while it is speaking â and modify its communicative behavior on-the-fly based on what it perceives from its partner. This report presents the results of a four week summer project that was part of eNTERFACEâ10. The project resulted in progress on several aspects of continuous interaction such as scheduling and interrupting multimodal behavior, automatic classification of listener responses, generation of response eliciting behavior, and models for appropriate reactions to listener responses. A pilot user study was conducted with ten participants. In addition, the project yielded a number of deliverables that are released for public access
Decay-assisted collinear resonance ionization spectroscopy: Application to neutron-deficient francium
This paper reports on the hyperfine-structure and radioactive-decay studies
of the neutron-deficient francium isotopes Fr performed with the
Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the ISOLDE
facility, CERN. The high resolution innate to collinear laser spectroscopy is
combined with the high efficiency of ion detection to provide a
highly-sensitive technique to probe the hyperfine structure of exotic isotopes.
The technique of decay-assisted laser spectroscopy is presented, whereby the
isomeric ion beam is deflected to a decay spectroscopy station for alpha-decay
tagging of the hyperfine components. Here, we present the first
hyperfine-structure measurements of the neutron-deficient francium isotopes
Fr, in addition to the identification of the low-lying states of
Fr performed at the CRIS experiment.Comment: Accepted for publication with Physical Review
Laser spectroscopy of francium isotopes at the borders of the region of reflection asymmetry
The magnetic dipole moments and changes in mean-square charge radii of the
neutron-rich isotopes were measured with the
newly-installed Collinear Resonance Ionization Spectroscopy (CRIS) beam line at
ISOLDE, CERN, probing the to atomic
transition. The values for
and follow the observed increasing
slope of the charge radii beyond . The charge radii odd-even
staggering in this neutron-rich region is discussed, showing that
has a weakly inverted odd-even staggering while
has normal staggering. This suggests that both isotopes
reside at the borders of a region of inverted staggering, which has been
associated with reflection-asymmetric shapes. The value supports a shell model configuration for the
ground state. The values support the tentative
spin, and point to a intruder ground state configuration.Comment: Accepted for publication with Physical Review
Virtual Reflexes
Virtual Reality is used successfully to treat people for regular phobias. A
new challenge is to develop Virtual Reality Exposure Training for social
skills. Virtual actors in such systems have to show appropriate social behavior
including emotions, gaze, and keeping distance. The behavior must be realistic
and real-time. Current approaches consist of four steps: 1) trainee social
signal detection, 2) cognitive-affective interpretation, 3) determination of
the appropriate bodily responses, and 4) actuation. The "cognitive" detour of
such approaches does not match the directness of human bodily reflexes and
causes unrealistic responses and delay. Instead, we propose virtual reflexes as
concurrent sensory-motor processes to control virtual actors. Here we present a
virtual reflexes architecture, explain how emotion and cognitive modulation are
embedded, detail its workings, and give an example description of an aggression
training application
Survival or Revival: Long-Term Preservation Induces a Reversible Viable but Non-Culturable State in Methane-Oxidizing Bacteria
Knowledge on long-term preservation of micro-organisms is limited and research in the field is scarce despite its importance for microbial biodiversity and biotechnological innovation. Preservation of fastidious organisms such as methane-oxidizing bacteria (MOB) has proven difficult. Most MOB do not survive lyophilization and only some can be cryopreserved successfully for short periods. A large-scale study was designed for a diverse set of MOB applying fifteen cryopreservation or lyophilization conditions. After three, six and twelve months of preservation, the viability (via live-dead flow cytometry) and culturability (via most-probable number analysis and plating) of the cells were assessed. All strains could be cryopreserved without a significant loss in culturability using 1% trehalose in 10-fold diluted TSB (TT) as preservation medium and 5% DMSO as cryoprotectant. Several other cryopreservation and lyophilization conditions, all of which involved the use of TT medium, also allowed successful preservation but showed a considerable loss in culturability. We demonstrate here that most of these non-culturables survived preservation according to viability assessment indicating that preservation induces a viable but non-culturable (VBNC) state in a significant fraction of cells. Since this state is reversible, these findings have major implications shifting the emphasis from survival to revival of cells in a preservation protocol. We showed that MOB cells could be significantly resuscitated from the VBNC state using the TT preservation medium
When to elicit feedback in dialogue: Towards a model based on the information needs of speakers
Buschmeier H, Kopp S. When to elicit feedback in dialogue: Towards a model based on the information needs of speakers. In: Proceedings of the 14th International Conference on Intelligent Virtual Agents. Boston, MA, USA; 2014: 71-80.Communicative feedback in dialogue is an important mechanism that helps interlocutors coordinate their interaction. Listeners pro-actively provide feedback when they think that it is important for the speaker to know their mental state, and speakers pro-actively seek listener feedback when they need information on whether a listener perceived, understood or accepted their message. This paper presents first steps towards a model for enabling attentive speaker agents to determine when to elicit feedback based on continuous assessment of their information needs about a user's listening state
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