Magnetic flux leakage testing is widely used to examine ferromagnetic materials. Considering the importance of estimating the size of surface crack in metals, which is used in nuclear power, railway and piping industr...
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Magnetic flux leakage testing is widely used to examine ferromagnetic materials. Considering the importance of estimating the size of surface crack in metals, which is used in nuclear power, railway and piping industries, a method based on particle swarm optimisation algorithm is proposed in this article. This approach maps the size of crack to the location of particles. After initialising the locations and velocities of the particle population, it evaluates the fitness value of the individual particle and tracks the optimal one. It then updates the positions and velocities of particles with the previous fitness values and repeats these steps until the best possible result is obtained. The fitness value is obtained by summing the absolute measurement error of the magnetic leakage field intensity of the crack. The results of simulation experiments demonstrate the effectiveness of the proposed method.
queue length variation. Yet, these conventional methods have been inefficient so far. Regarding the stochastic attributes of communication networks, AQM methods based on stochastic theory perform better in comparison ...
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queue length variation. Yet, these conventional methods have been inefficient so far. Regarding the stochastic attributes of communication networks, AQM methods based on stochastic theory perform better in comparison with conventional AQM methods. A new stochastic AQM advances is advised for the control of queue length probability density function (PDF) for transmission control protocol (TCP). The Parzen window estimate of PDFs exploitation the kernel function is used to constitute the queue PDFs of the TCP/AQM routers. This study proposes a novel stochastic AQM algorithm called hyperbolic random early detection (PDF-HRED) as an appendage of random early detection (RED). The PDF-HRED is based on a stochastic PDF estimation, an HRED controller and particleswarmoptimisation (PSO). The numerical simulation results by NS2 demonstrate that the PDF-HRED controller outperforms the existing AQM schemes with respect to performance characteristics.
Wastewater treatment plants (WWTPs) are major energy consumers and cause environmental impact on receiving waters. Many WWTPs are operated in a less-than-optimal manner with respect to both treatment and energy effici...
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Wastewater treatment plants (WWTPs) are major energy consumers and cause environmental impact on receiving waters. Many WWTPs are operated in a less-than-optimal manner with respect to both treatment and energy efficiency. A better solution is to optimize the operation and processes of the existing WWTPs. Therefore, the most effective process parameter for providing control strategies was *** South WWTP of Tehran was designed and simulated based on the activated sludge model using MATLAB/ Simulink software for the first time in the country to obtain the factors affecting WWTP. To calibrate this model some kinetic and stoichiometric coefficients were determined. Then the simulator validation was performed by three error calculation methods. Finally, the values of three main controllers, including the optimum rate or return activated sludge (RAS), internal recycle (IR) and oxygen transfer coefficient (KLa) are determined using the particleswarm Optimization algorithm. According to the results, coefficients such as Y, kd, K and KS for Oxidation-Ditch process were in the range of 0.303-0.331mgVSS /mg sCOD, 0.030-0.033 1/day, 1.65-1.93 1/day and 37.6-44.92 mg sCOD/l, respectively and the Mean of COD, BOD5, TSS and TN removal was obtained 94.8 +/- 0.4, 97.3 +/- 0.65, 94.7 +/- 1.5 and 56 +/- 7.46, respectively. Also, the percentage of Root Mean Square for TN, TSS, COD, BOD5 was 3.14%, 2.95%, 3.13% and 5.2%, respectively, Pearson correlation coefficient was 0.88, 0.93, 0.89, 0.99 and absolute mean error of 2.62%, 2.47%, 2.6% and 3.58%, respectively, which shows that the simulation outputs are compatible with the effluent of plant. To achieve the best process performance conditions, RAS and IR must be considered for 1.7 and 0.8 percent of influent wastewater and KLa is suggested to be 154 d(-1). Therefore, by using the optimization performed, the effect of other controllers on the process can be investigated and selected.
algorithms based on the genetic algorithm (GA) and the particleswarmoptimisation (PSO) algorithm were designed for focusing inverse synthetic aperture radar (ISAR) images that suffered from degradation because of Do...
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algorithms based on the genetic algorithm (GA) and the particleswarmoptimisation (PSO) algorithm were designed for focusing inverse synthetic aperture radar (ISAR) images that suffered from degradation because of Doppler smearing. These algorithms optimised the adaptive joint-time-frequency (AJTF) algorithm by replacing the exhaustive search as the primary search tool used to determine focusing parameters. The use of the PSO for ISAR image focusing is a unique application of this evolutionary search. Performance of the GA and the PSO were compared with the PSO producing the optimal results of being able to focus a 2(11) pulse ISAR image with second-order motion error in 9 s or 24% of the cost function calculations required for an exhaustive search. The PSO algorithm was then applied to a 2(11) pulse ISAR image with fourth-order motion error. The PSO algorithm was able to focus this image in 20 s with 33% of the cost function calculations required by the exhaustive search. This study also introduces a new method of determining basis function suitability using the fast Fourier transform.
A standalone wind/solar/battery hybrid power system, making full use of the nature complementarity between wind and solar energy, has an extensive application prospect among various newly developed energy technologies...
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A standalone wind/solar/battery hybrid power system, making full use of the nature complementarity between wind and solar energy, has an extensive application prospect among various newly developed energy technologies. The capacity of the hybrid power system needs to be optimised in order to make a tradeoff between power reliability and cost. In this study, each part of the wind/solar/battery hybrid power system is analysed in detail and an objective function combining total owning cost and loss of power supply probability is built. To solve the problems with non-linearity, complexity and huge computation, an improved particleswarmoptimisation (PSO) algorithm is developed, which integrates the taboo list to broaden the search range and introduces 'restart' and 'disturbance' operation to enhance the global searching capability. The simulation results indicate that the proposed algorithm is more stable and provides better results in solving the optimal allocation of the capacity of the standalone wind/solar/battery hybrid power system compared with the standard PSO algorithm.
The QR decomposition (QRD)-based relaying protocol can achieve both the distributed array gain and the intra-node array gain in multi-input multi-output multi-relay systems. In this paper, the distributed precoding te...
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The QR decomposition (QRD)-based relaying protocol can achieve both the distributed array gain and the intra-node array gain in multi-input multi-output multi-relay systems. In this paper, the distributed precoding technique is first utilised in the QRD-based multi-relay system to further improve the capacity performance of the system. In order to find the optimum distributed precoder, a novel version of the particleswarmoptimisation (PSO) algorithm is presented by redefining the evolution of particles on the spherical surface. Then, the complexity analysis of the proposed PSO algorithm is carried out to show its feasibility. Finally, numerical and simulation results demonstrate the performance gain of the proposed design in terms of the ergodic capacity.
Grey theory explores the use of the PSO algorithm and this paper analysed the feasibility of using this algorithm to forecast the residual life of underground pipeline. It is allowed to offer fewer data while using th...
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Grey theory explores the use of the PSO algorithm and this paper analysed the feasibility of using this algorithm to forecast the residual life of underground pipeline. It is allowed to offer fewer data while using this method to forecast its residual life. Example shows that the method of the PSO algorithm based on grey theory optimisation is superior to the existing forecasting methods such as the grey forecasting method and grey theory based on the GA optimisation method.
To ensure the reliable operation of high voltage cables, it is crucial to routinely inspect the lead sealing using pulsed eddy current. But nevertheless, the signals can be impacted by noise in actual engineering. Whi...
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To ensure the reliable operation of high voltage cables, it is crucial to routinely inspect the lead sealing using pulsed eddy current. But nevertheless, the signals can be impacted by noise in actual engineering. While retaining the useful high-frequency information in the original signal, wavelet denoising can filter the clutter efficiently. However, previous research on wavelet denoising has only used it as a straightforward filtering tool, ignoring the impact of changing the parameters on the actual denoising effect. In this study, a more accurate evaluation index called P-NCC is constructed for pulsed eddy current testing signals with a focus on maintaining the peak information. This index is then adopted as a fitness function for the particle swarm optimisation algorithm to determine the befitting wavelet denoising parameters and denoised signals. The results show that the signal-to-noise ratio of the signals after denoising is approximately 25 dB, and the distortion at the peak position is stable at about 1%. It demonstrates that the comprehensive index P-NCC is a reliable metric for assessing the quality of pulsed eddy current signals. The optimal wavelet denoising parameters for pulsed eddy current signals are found to be the Sym 4 wavelet, 10-layer decomposition and Median threshold function.
The growth of mobile handheld devices promotes sink mobility in an increasing number of wireless sensor networks (WSNs) applications. The movement of the sink may lead to the breakage of existing routes of WSNs, thus ...
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The growth of mobile handheld devices promotes sink mobility in an increasing number of wireless sensor networks (WSNs) applications. The movement of the sink may lead to the breakage of existing routes of WSNs, thus the routing recovery problem is a critical challenge. In order to maintain the available route from each source node to the sink, we propose an immune orthogonal learning particle swarm optimisation algorithm (IOLPSOA) to provide fast routing recovery from path failure due to the sink movement, and construct the efficient alternative path to repair the route. Due to its efficient bio-heuristic routing recovery mechanism in the algorithm, the orthogonal learning strategy can guide particles to fly on better directions by constructing a much promising and efficient exemplar, and the immune mechanism can maintain the diversity of the particles. We discuss the implementation of the IOLPSOA-based routing protocol and present the performance evaluation through several simulation experiments. The results demonstrate that the IOLPSOA-based protocol outperforms the other three protocols, which can efficiently repair the routing topology changed by the sink movement, reduce the communication overhead and prolong the lifetime of WSNs with mobile sink.
This paper involves the application of particleswarmoptimisation in the optimisation problem of reactive power. The optimisation model of reactive power is first introduced and the improved strategy of particle swar...
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This paper involves the application of particleswarmoptimisation in the optimisation problem of reactive power. The optimisation model of reactive power is first introduced and the improved strategy of particleswarmoptimisation is proposed for the problem of optimisation of reactive power in this paper. In order to improve the local search ability, the disturbance item is given for the updating equation of the particle in the improved strategy. The numerical examples of standard IEEE-6 and IEEE-30 power systems for the improved strategy of particleswarmoptimisation are performed for the reactive power optimisation. The effectiveness of the improved strategy proposed in this paper has been demonstrated preliminarily from the numerical examples.
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