11,223 research outputs found
Strategies for distributing goals in a team of cooperative agents
This paper addresses the problem of distributing goals to individual agents inside a team of cooperative agents. It shows that several parameters determine the goals of particular agents. The first parameter is the set of goals allocated to the team; the second parameter is the description of the real actual world; the third parameter is the description of the agents' ability and commitments. The last parameter is the strategy the team agrees on: for each precise goal, the team may define several strategies which are orders between agents representing, for instance, their relative competence or their relative cost. This paper also shows how to combine strategies. The method used here assumes an order of priority between strategie
Large Area Crop Inventory Experiment (LACIE). Evaluation of multitemporal data enchancements for the identification of winter wheat fields
There are no author-identified significant results in this report
A Stellar Census of the Tucana-Horologium Moving Group
We report the selection and spectroscopic confirmation of 129 new late-type
(K3-M6) members of the Tuc-Hor moving group, a nearby (~40 pc), young (~40 Myr)
population of comoving stars. We also report observations for 13/17 known
Tuc-Hor members in this spectral type range, and that 62 additional candidates
are likely to be unassociated field stars; the confirmation frequency for new
candidates is therefore 129/191 = 67%. We have used RVs, Halpha emission, and
Li6708 absorption to distinguish contaminants and bona fide members. Our
expanded census of Tuc-Hor increases the known population by a factor of ~3 in
total and by a factor of ~8 for members with SpT>K3, but even so, the K-M dwarf
population of Tuc-Hor is still markedly incomplete. The spatial distribution of
members appears to trace a 2D sheet, with a broad distribution in X and Y, but
a very narrow distribution (+/-5 pc) in Z. The corresponding velocity
distribution is very small, with a scatter of +/-1.1 km/s about the mean UVW
velocity. We also show that the isochronal age (20--30 Myr) and the lithium
depletion age (40 Myr) disagree, following a trend seen in other PMS
populations. The Halpha emission follows a trend of increasing EW with later
SpT, as seen for young clusters. We find that members have been depleted of
lithium for spectral types of K7.0-M4.5. Finally, our purely kinematic and
color-magnitude selection procedure allows us to test the efficiency and
completeness for activity-based selection of young stars. We find that 60% of
K-M dwarfs in Tuc-Hor do not have ROSAT counterparts and would be omitted in
Xray selected samples. GALEX UV-selected samples using a previously suggested
criterion for youth achieve completeness of 77% and purity of 78%. We suggest
new selection criteria that yield >95% completeness for ~40 Myr
populations.(Abridged)Comment: Accepted to AJ; 28 pages, 12 figures, 5 tables in emulateapj forma
Kraus representation for density operator of arbitrary open qubit system
We show that the time evolution of density operator of open qubit system can
always be described in terms of the Kraus representation. A general scheme on
how to construct the Kraus operators for an open qubit system is proposed,
which can be generalized to open higher dimensional quantum systems.Comment: 5 pages, no figures. Some words are rephrase
Transition behavior in the capacity of correlated-noisy channels in arbitrary dimensions
We construct a class of quantum channels in arbitrary dimensions for which
entanglement improves the performance of the channel. The channels have
correlated noise and when the level of correlation passes a critical value we
see a sharp transition in the optimal input states (states which minimize the
output entropy) from separable to maximally entangled states. We show that for
a subclass of channels with some extra conditions, including the examples which
we consider, the states which minimize the output entropy are the ones which
maximize the mutual information.Comment: 11 pages, Latex, 4 figures, Accepted for publication in Physical
Review
A Parallel General Purpose Multi-Objective Optimization Framework, with Application to Beam Dynamics
Particle accelerators are invaluable tools for research in the basic and
applied sciences, in fields such as materials science, chemistry, the
biosciences, particle physics, nuclear physics and medicine. The design,
commissioning, and operation of accelerator facilities is a non-trivial task,
due to the large number of control parameters and the complex interplay of
several conflicting design goals. We propose to tackle this problem by means of
multi-objective optimization algorithms which also facilitate a parallel
deployment. In order to compute solutions in a meaningful time frame a fast and
scalable software framework is required. In this paper, we present the
implementation of such a general-purpose framework for simulation-based
multi-objective optimization methods that allows the automatic investigation of
optimal sets of machine parameters. The implementation is based on a
master/slave paradigm, employing several masters that govern a set of slaves
executing simulations and performing optimization tasks. Using evolutionary
algorithms as the optimizer and OPAL as the forward solver, validation
experiments and results of multi-objective optimization problems in the domain
of beam dynamics are presented. The high charge beam line at the Argonne
Wakefield Accelerator Facility was used as the beam dynamics model. The 3D beam
size, transverse momentum, and energy spread were optimized
- …