615 research outputs found
Laser tuning parameters and concentration retrieval technique for wavelength modulation spectroscopy based on the variable-radius search artificial bee colony algorithm
A novel wavelength modulation spectroscopy (WMS) laser tuning parameters and
concentration retrieval technique based on the variable-radius-search
artificial bee colony(VRS-ABC) algorithm is proposed. The technique imitates
the foraging behavior of bees to achieve the retrieval of gas concentration and
laser tuning parameters in a calibration-free WMS system. To address the
problem that the basic artificial bee colony(ABC) algorithm tends to converge
prematurely, we improve the search method of the scout bee. In contrast to
prior concentration retrieval methods that utilized the Levenberg-Marquardt
algorithm, the current technique exhibits a reduced dependence on the
pre-characterization of laser parameters, leading to heightened precision and
reliability in concentration retrieval. We validated the simulation with the
VRS-ABC-based technique and the LM-based technique for the target gas C2H2. The
simulation results show that the VRS-ABC-based technique performs better in
terms of convergence speed and fitting accuracy, especially in the
multi-parameter model without exact characterization
Concentration retrieval in a calibration-free wavelength modulation spectroscopy system using particle swarm optimization algorithm
This paper develops a spectral fitting technology based on the particle swarm
optimization (PSO) algorithm, which is applied to a calibration-free wavelength
modulation spectroscopy system to achieve concentration retrieval. As compared
with other spectral fitting technology based on the Levenberg-Marquardt (LM)
algorithm, this technology is relatively weakly dependent on the
pre-characterization of the laser parameters. The gas concentration is
calculated by fitting the simulated spectra to the measured spectra using the
PSO algorithm. We validated the simulation with the LM algorithm and PSO
algorithm for the target gas C2H2. The results showed that the convergence
speed of the spectral fitting technique based on the PSO algorithm was about 63
times faster than the LM algorithm when the fitting accuracy remained the same.
Within 5 seconds, the PSO algorithm can produce findings that are generally
consistent with the values anticipated.Comment: arXiv admin note: text overlap with arXiv:2210.1654
Dynamic Demand Forecast and Assignment Model for Bike-and-Ride System
Bike-and-Ride (B&R) has long been considered as an effective way to deal with urbanization-related issues such as traffic congestion, emissions, equality, etc. Although there are some studies focused on the B&R demand forecast, the influencing factors from previous studies have been excluded from those forecasting methods. To fill this gap, this paper proposes a new B&R demand forecast model considering the influencing factors as dynamic rather than fixed ones to reach higher forecasting accuracy. This model is tested in a theoretical network to validate the feasibility and effectiveness and the results show that the generalised cost does have an effect on the demand for the B&R system.</p
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