4,083 research outputs found
An improved optimization technique for estimation of solar photovoltaic parameters
The nonlinear current vs voltage (I-V) characteristics of solar PV make its modelling difficult. Optimization techniques are the best tool for identifying the parameters of nonlinear models. Even though, there are different optimization techniques used for parameter estimation of solar PV, still the best optimized results are not achieved to date. In this paper, Wind Driven Optimization (WDO) technique is proposed as the new method for identifying the parameters of solar PV. The accuracy and convergence time of the proposed method is compared with results of Pattern Search (PS), Genetic Algorithm (GA), and Simulated Annealing (SA) for single diode and double diode models of solar PV. Furthermore, for performance validation, the parameters obtained through WDO are compared with hybrid Bee Pollinator Flower Pollination Algorithm (BPFPA), Flower Pollination Algorithm (FPA), Generalized Oppositional Teaching Learning Based Optimization (GOTLBO), Artificial Bee Swarm Optimization (ABSO), and Harmony Search (HS). The obtained results clearly reveal that WDO algorithm can provide accurate optimized values with less number of iterations at different environmental conditions. Therefore, the WDO can be recommended as the best optimization algorithm for parameter estimation of solar PV
進化的及び樹状突起のメカニズムを考慮したソフトコンピューティング技術の提案
富山大学・富理工博甲第117号・宋振宇・2017/03/23富山大学201
A new perspective on the irregular satellites of Saturn - I Dynamical and collisional history
The dynamical features of the irregular satellites of the giant planets argue
against an in-situ formation and are strongly suggestive of a capture origin.
Since the last detailed investigations of their dynamics, the total number of
satellites have doubled, increasing from 50 to 109, and almost tripled in the
case of Saturn system. We have performed a new dynamical exploration of Saturn
system to test whether the larger sample of bodies could improve our
understanding of which dynamical features are primordial and which are the
outcome of the secular evolution of the system. We have performed detailed
N--Body simulations using the best orbital data available and analysed the
frequencies of motion to search for resonances and other possible perturbing
effects. We took advantage of the Hierarchical Jacobian Symplectic algorithm to
include in the dynamical model of the system also the gravitational effects of
the two outermost massive satellites, Titan and Iapetus. Our results suggest
that Saturn's irregular satellites have been significantly altered and shaped
by the gravitational perturbations of Jupiter, Titan, Iapetus and the Sun and
by the collisional sweeping effect of Phoebe. In particular, the effects on the
dynamical evolution of the system of the two massive satellites appear to be
non-negligible. Jupiter perturbs the satellites through its direct
gravitational pull and, indirectly, via the effects of the Great Inequality,
i.e. its almost resonance with Saturn. Finally, by using the Hierarchical
Clustering Method we found hints to the existence of collisional families and
compared them with the available observational data.Comment: 26 Pages, 27 Figures, 4 Table
Chaos embedded opposition based learning for gravitational search algorithm
Due to its robust search mechanism, Gravitational search algorithm (GSA) has
achieved lots of popularity from different research communities. However,
stagnation reduces its searchability towards global optima for rigid and
complex multi-modal problems. This paper proposes a GSA variant that
incorporates chaos-embedded opposition-based learning into the basic GSA for
the stagnation-free search. Additionally, a sine-cosine based chaotic
gravitational constant is introduced to balance the trade-off between
exploration and exploitation capabilities more effectively. The proposed
variant is tested over 23 classical benchmark problems, 15 test problems of CEC
2015 test suite, and 15 test problems of CEC 2014 test suite. Different
graphical, as well as empirical analyses, reveal the superiority of the
proposed algorithm over conventional meta-heuristics and most recent GSA
variants.Comment: 33 pages, 5 Figure
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