3,845 research outputs found
An agent-based intelligent system for information gathering from world wide web environment
To use the vast amount of information efficiently and effectively from Web sites is very important for making informed decisions. There are, however, still many problems that need to be overcome in the information gathering research arena to enable the delivery of relevant information required by users. In this paper, an information gathering system is develop by means of multiple agents to solve those problems. We employed some ideas of Gaia\u27s methodology and an open agent architecture to analyze and design the system. The system consists of a query preprocessing agent, information retrieval agent, information filtering agent, and information management agent. The filtering agent is trained with categorized documents and can provide users with the necessary information. The experimental results show that all agents in the system can work cooperatively to retrieve relevant information from the World Wide Web environment. <br /
Negative entanglement measure for bipartite separable mixed states
We define a negative entanglement measure for separable states which shows
that how much entanglement one should compensate the unentangled state at least
for changing it into an entangled state. For two-qubit systems and some special
classes of states in higher-dimensional systems, the explicit formula and the
lower bounds for the negative entanglement measure have been presented, and it
always vanishes for bipartite separable pure states. The negative entanglement
measure can be used as a useful quantity to describe the entanglement dynamics
and the quantum phase transition. In the transverse Ising model, the first
derivatives of negative entanglement measure diverge on approaching the
critical value of the quantum phase transition, although these two-site reduced
density matrices have no entanglement at all. In the 1D Bose-Hubbard model, the
NEM as a function of changes from zero to negative on approaching the
critical point of quantum phase transition.Comment: 6 pages, 3 figure
catena-Poly[[dichloridonickel(II)]-μ-1,3-di-4-pyridylpropane]
The title compound, [NiCl2(C13H14N2)]n, is a one-dimensional polymer built up from alternating NiCl2 units and bridging 1,3-di-4-pyridylpropane ligands. The Ni atom has a distorted tetrahedral coordination formed by the Cl atoms and two N atoms from two ligands. A mirror plane pases through the central methylene group of the propyl chain
2-(5-Amino-2H-tetrazol-2-yl)acetic acid
In the title molecule, C3H5N5O2, the tetrazole ring and carboxyl group form a dihedral angle of 82.25 (14)°. In the crystal, adjacent molecules are linked through O—H⋯N, N—H⋯O and N—H⋯N hydrogen bonds into layers parallel to the bc plane
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