58,968 research outputs found
Chemical reaction optimization for the set covering problem
The set covering problem (SCP) is one of the representative combinatorial optimization problems, having many practical applications. This paper investigates the development of an algorithm to solve SCP by employing chemical reaction optimization (CRO), a general-purpose metaheuristic. It is tested on a wide range of benchmark instances of SCP. The simulation results indicate that this algorithm gives outstanding performance compared with other heuristics and metaheuristics in solving SCP. © 2014 IEEE.postprin
Electric Vehicle Charging Station Placement: Formulation, Complexity, and Solutions
To enhance environmental sustainability, many countries will electrify their
transportation systems in their future smart city plans. So the number of
electric vehicles (EVs) running in a city will grow significantly. There are
many ways to re-charge EVs' batteries and charging stations will be considered
as the main source of energy. The locations of charging stations are critical;
they should not only be pervasive enough such that an EV anywhere can easily
access a charging station within its driving range, but also widely spread so
that EVs can cruise around the whole city upon being re-charged. Based on these
new perspectives, we formulate the Electric Vehicle Charging Station Placement
Problem (EVCSPP) in this paper. We prove that the problem is non-deterministic
polynomial-time hard. We also propose four solution methods to tackle EVCSPP
and evaluate their performance on various artificial and practical cases. As
verified by the simulation results, the methods have their own characteristics
and they are suitable for different situations depending on the requirements
for solution quality, algorithmic efficiency, problem size, nature of the
algorithm, and existence of system prerequisite.Comment: Submitted to IEEE Transactions on Smart Grid, revise
Parameter estimation in spatially extended systems: The Karhunen-Loeve and Galerkin multiple shooting approach
Parameter estimation for spatiotemporal dynamics for coupled map lattices and
continuous time domain systems is shown using a combination of multiple
shooting, Karhunen-Loeve decomposition and Galerkin's projection methodologies.
The resulting advantages in estimating parameters have been studied and
discussed for chaotic and turbulent dynamics using small amounts of data from
subsystems, availability of only scalar and noisy time series data, effects of
space-time parameter variations, and in the presence of multiple time-scales.Comment: 11 pages, 5 figures, 4 Tables Corresponding Author - V. Ravi Kumar,
e-mail address: [email protected]
Computational Strategy for Graphene: Insight from Odd Electrons Correlation
The correlation of odd electrons in graphene turns out to be significant so
that the species should be attributed to correlated ones. This finding
profoundly influences the computational strategy addressing it to
multireference computational schemes. Owing to serious problems related to the
schemes realization, a compromise can be suggested by using single-determinant
approaches based on either Hartree-Fock or Density-Functional theory in the
form of unrestricted open-shell presentation. Both computational schemes enable
to fix the electron correlation, while only the Hartree-Fock theory suggests a
set of quantities to be calculated that can quantitatively characterize the
electron correlation and be used for a quantitative description of such
graphene properties as magnetism, chemical reactivity, and mechanical response.
The paper presents concepts and algorithms of the unrestricted Hartree-Fock
theory applied for the consideration of magnetic properties of nanographenes,
their chemical modification by the example of stepwise hydrogenation, as well
as a possible governing the electron correlation by the carbon skeleton
deformation.Comment: 17 pages, 11 figures, 3 table
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