91,132 research outputs found
On the convergence of autonomous agent communities
This is the post-print version of the final published paper that is available from the link below. Copyright @ 2010 IOS Press and the authors.Community is a common phenomenon in natural ecosystems, human societies as well as artificial multi-agent systems such as those in web and Internet based applications. In many self-organizing systems, communities are formed evolutionarily in a decentralized way through agents' autonomous behavior. This paper systematically investigates the properties of a variety of the self-organizing agent community systems by a formal qualitative approach and a quantitative experimental approach. The qualitative formal study by applying formal specification in SLABS and Scenario Calculus has proven that mature and optimal communities always form and become stable when agents behave based on the collective knowledge of the communities, whereas community formation does not always reach maturity and optimality if agents behave solely based on individual knowledge, and the communities are not always stable even if such a formation is achieved. The quantitative experimental study by simulation has shown that the convergence time of agent communities depends on several parameters of the system in certain complicated patterns, including the number of agents, the number of community organizers, the number of knowledge categories, and the size of the knowledge in each category
Joint Dynamic Radio Resource Allocation and Mobility Load Balancing in 3GPP LTE Multi-Cell Network
Load imbalance, together with inefficient utilization of system resource, constitute major factors responsible for poor overall performance in Long Term Evolution (LTE) network. In this paper, a novel scheme of joint dynamic resource allocation and load balancing is proposed to achieve a balanced performance improvement in 3rd Generation Partnership Project (3GPP) LTE Self-Organizing Networks (SON). The new method which aims at maximizing network resource efficiency subject to inter-cell interference and intra-cell resource constraints is implemented in two steps. In the first step, an efficient resource allocation, including user scheduling and power assignment, is conducted in a distributed manner to serve as many users in the whole network as possible. In the second step, based on the resource allocation scheme, the optimization objective namely network resource efficiency can be calculated and load balancing is implemented by switching the user that can maximize the objective function. Lagrange Multipliers method and heuristic algorithm are used to resolve the formulated optimization problem. Simulation results show that our algorithm achieves better performance in terms of user throughput, fairness, load balancing index and unsatisfied user number compared with the traditional approach which takes resource allocation and load balancing into account, respectively
Navigation in a small world with local information
It is commonly known that there exist short paths between vertices in a
network showing the small-world effect. Yet vertices, for example, the
individuals living in society, usually are not able to find the shortest paths,
due to the very serious limit of information. To theoretically study this
issue, here the navigation process of launching messages toward designated
targets is investigated on a variant of the one-dimensional small-world network
(SWN). In the network structure considered, the probability of a shortcut
falling between a pair of nodes is proportional to , where is
the lattice distance between the nodes. When , it reduces to the SWN
model with random shortcuts. The system shows the dynamic small-world (SW)
effect, which is different from the well-studied static SW effect. We study the
effective network diameter, the path length as a function of the lattice
distance, and the dynamics. They are controlled by multiple parameters, and we
use data collapse to show that the parameters are correlated. The central
finding is that, in the one-dimensional network studied, the dynamic SW effect
exists for . For each given value of in this
region, the point that the dynamic SW effect arises is ,
where is the number of useful shortcuts and is the average
reduced (effective) length of them.Comment: 10 pages, 5 figures, accepted for publication in Physical Review
Topological Characterization of Non-Abelian Moore-Read State using Density-Matrix Renormailzation Group
The non-Abelian topological order has attracted a lot of attention for its
fundamental importance and exciting prospect of topological quantum
computation. However, explicit demonstration or identification of the
non-Abelian states and the associated statistics in a microscopic model is very
challenging. Here, based on density-matrix renormalization group calculation,
we provide a complete characterization of the universal properties of bosonic
Moore-Read state on Haldane honeycomb lattice model at filling number
for larger systems, including both the edge spectrum and the bulk anyonic
quasiparticle (QP) statistics. We first demonstrate that there are three
degenerating ground states, for each of which there is a definite anyonic flux
threading through the cylinder. We identify the nontrivial countings for the
entanglement spectrum in accordance with the corresponding conformal field
theory. Through inserting the charge flux, it is found that two of the
ground states can be adiabatically connected through a fermionic
charge- QP being pumped from one edge to the other, while the
ground state in Ising anyon sector evolves back to itself. Furthermore, we
calculate the modular matrices and , which contain
all the information for the anyonic QPs. In particular, the extracted quantum
dimensions, fusion rule and topological spins from modular matrices positively
identify the emergence of non-Abelian statistics following the
Chern-Simons theory.Comment: 5 pages; 3 figure
The Fractional Quantum Hall States at and and their Non-Abelian Nature
We investigate the nature of the fractional quantum Hall (FQH) state at
filling factor , and its particle-hole conjugate state at ,
with the Coulomb interaction, and address the issue of possible competing
states. Based on a large-scale density-matrix renormalization group (DMRG)
calculation in spherical geometry, we present evidence that the physics of the
Coulomb ground state (GS) at and is captured by the
parafermion Read-Rezayi RR state, . We first establish that the
state at is an incompressible FQH state, with a GS protected by a
finite excitation gap, with the shift in accordance with the RR state. Then, by
performing a finite-size scaling analysis of the GS energies for
with different shifts, we find that the state has the lowest
energy among different competing states in the thermodynamic limit. We find the
fingerprint of topological order in the FQH and
states, based on their entanglement spectrum and topological entanglement
entropy, both of which strongly support their identification with the
state. Furthermore, by considering the shift-free
infinite-cylinder geometry, we expose two topologically-distinct GS sectors,
one identity sector and a second one matching the non-Abelian sector of the
Fibonacci anyonic quasiparticle, which serves as additional evidence for the
state at and .Comment: 12 pages, 8 figure
Semantic web-based document: editing and browsing in AktiveDoc
This paper presents a tool for supporting sharing and reuse of knowledge in document creation (writing) and use (reading). Semantic Web technologies are used to support the production of ontology based annotations while the document is written. Free text annotations (comments) can be added to integrate the knowledge in the document. In addition the tool uses external services (e.g. a Semantic Web harvester) to propose relevant content to writing
user, enabling easy knowledge reuse. Similar facilities are provided for readers when their task does not coincide with the authorâs one. The tool is specifically designed for Knowledge Management in organisations. In this paper we present and discuss how Semantic Web technologies are designed and integrated in the system
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