The motif discovery problem (MDP) is an important biological optimization problem that has been addressed in numerous ways. However, it is important to note that when we address real complex optimization problems, we ...
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The motif discovery problem (MDP) is an important biological optimization problem that has been addressed in numerous ways. However, it is important to note that when we address real complex optimization problems, we should adequately formulate them in order to provide real applicability to the developed techniques. In the particular case of MDP, as we do not know the size of the motifs and the number of repetitions that can be found in the sequences, we must not make any length or pattern-repetition assumptions. In addition, if we consider that it is practically impossible to adequately formulate an optimization problem with a single-objective function formulation, multiobjective optimization can be a good methodology to be considered. In this paper, we propose a novel hybrid multiobjective algorithm for tackling the MDP. Our main objective is to study the results achieved by our algorithm, analysing its performance when different motif occurrence models are considered. As we will see, experimental results on different sets of real instances will point out the advantages and disadvantages of each model, also checking how a more realistic definition of the optimized problem provides better quality biological results.
This paper presents an efficient and reliable evolutionary-based approach to solve the Optimal Power Flow (OPF) problem by considering the emission issue. The OPF problem has been widely used in power system operation...
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This paper presents an efficient and reliable evolutionary-based approach to solve the Optimal Power Flow (OPF) problem by considering the emission issue. The OPF problem has been widely used in power system operation and planning for determining electricity prices. Therefore, the conventional optimal power flow cannot meet the environmental protection requirements, because it only considers generation cost minimization. The multi-objective optimal power flow considers economical and emission issues. By adding the emission objective in the optimal power flow problem, this problem become more complicated than before and it needs to be solved with an accurate algorithm. This paper proposes an algorithm based on the shuffle frog leaping algorithm (SLFA) to solve the multi-objective OPF problem. Furthermore, this paper presents a modified SLFA called MSLFA algorithm which profits from a mutation in order to reduce the processing time and improve the quality of solutions, particularly to avoid being trapped in local optima. The IEEE 30-bus test system is presented to illustrate the application of the proposed problem. (C) 2011 Elsevier Ltd. All rights reserved.
To address the issues of high energy costs and inadequate system response speed in complex electricity markets, we propose an electricity price optimization model. This model combines an improved Particle Swarm Optimi...
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To address the issues of high energy costs and inadequate system response speed in complex electricity markets, we propose an electricity price optimization model. This model combines an improved Particle Swarm Optimization algorithm, Quantum-behaved Particle Swarm Optimization, and the shuffle frog leaping algorithm. The work was based on multi-regional peak and valley data, and we selected Lanzhou, Guiyang, Beijing, Guangzhou, Shanghai, and Nanjing as typical representatives for systematic validation and analysis. Our findings were as follows: (1) The model demonstrated excellent convergence and stability during the electricity price optimization process, particularly under flat-rate price conditions. This model effectively avoided local optima traps and enhanced global search capability, achieving the dual goals of rapid convergence and high stability, and showed exceptional optimization efficiency and adaptability;(2) building upon its optimization performance, the model further improved the uniformity and diversity of the solution distribution, ensuring robustness and flexibility in global search ability. Moreover, by dynamically adjusting the price function and multi-level evaluation system, the model significantly optimized price elasticity, time-of-use pricing regulation efficiency, energy consumption paths, and the operational stability of the distribution network. The model exhibited high resilience and fine-grained control capabilities in the complex electricity market;(3) finally, based on the optimized electricity price strategy derived from training, the model reduced electricity costs and price volatility. Moreover, its superior performance in economic benefits and market adaptability was comprehensively validated through high-precision power consumption forecasting. We aimed to optimize energy costs, improve system response speed, and reduce price volatility, thereby achieving more efficient energy utilization and economic benefits.
In this paper, an effective and reliable algorithm, based on shuffle frog leaping algorithm (SFLA) and Simulated Annealing (SA) is proposed for solving the optimal power flow (OPF) problem with non-smooth and non-conv...
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In this paper, an effective and reliable algorithm, based on shuffle frog leaping algorithm (SFLA) and Simulated Annealing (SA) is proposed for solving the optimal power flow (OPF) problem with non-smooth and non-convex generator fuel cost characteristics. Also, the proposed OPF formulation contains detailed generator constraints including active and reactive power generation limits, valve loading effects, and Prohibited Operating Zones (POZs) of units. OPF is spontaneously a complicate optimization problem, and becomes more and more complex considering the above constraints. Therefore, it needs to be solved with an accurate algorithm. Recently researchers have presented a new evolutionary method called SFLA algorithm. The original SFLA often converges to local optima. In order to avoid this shortcoming we propose a new method that profits from SA algorithm to improve local search near the global optima. The possibility of convergence to global optima is increased using the proposed method. For validating the proposed algorithm, it has been examined on the standard IEEE 30-bus test systems. The hybrid SFLA-SA provides better results compared to the original SFLA. SA, and other methods recently reported in the literature as demonstrated by simulation results. (C) 2012 Elsevier Ltd. All rights reserved.
This paper presents a new hybrid algorithm based on the Particle Swarm Optimization (PSO) and the shuffle frog leaping algorithms (SFLA) for solving the Optimal Power Flow (OFF) in power systems. In consequence of eco...
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This paper presents a new hybrid algorithm based on the Particle Swarm Optimization (PSO) and the shuffle frog leaping algorithms (SFLA) for solving the Optimal Power Flow (OFF) in power systems. In consequence of economical issues and increasing of the social welfare, the OPF problem is turning into a pretty remarkable problem and getting more and more important in power systems. The proposed optimization problem has considered the real conditions of power generation involving the prohibit zones, valve point effect and multi-fuel type of generation units. Increasing concerns over the environmental issues forced the power system operators to consider the emission problem as a consequential matter beside the economic problems, so the OPF problem has become a multi-objective optimization problem. This paper takes advantages of the Pareto optimal solution and fuzzy decision making method in order to achieve the set of optimal solutions and best compromise solution, respectively. The presented algorithm is applied to 30, 57 and 118-bus test systems and the obtained results are compared with those in literature. (C) 2012 Elsevier Ltd. All rights reserved.
An accurate solution method is essential to the calibration of the nonlinear Muskingum model. Most of the earlier researchers have used inaccurate Euler’s solution method which is manipulated to get a better fit for ...
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An accurate solution method is essential to the calibration of the nonlinear Muskingum model. Most of the earlier researchers have used inaccurate Euler’s solution method which is manipulated to get a better fit for observed Wilson’s data (1974). Euler’s method which is adopted by most previous researchers is not very accurate and results in unsuitable simulation based on the nonlinear Muskingum model as shown in this discussion. This study proposes fourth-order Runge-Kutta method as a suitable and accurate solution method for simulation stage. When more accuracy is needed, the structure of the Muskingum model can be modified to produce more degree of freedom in model calibration procedure. For this purpose, a new five-parameter nonlinear Muskingum model is proposed. The proposed model is easy to formulate and use. The results show that the improvement in the fit of the proposed nonlinear Muskingum model is substantial.
Increasing demand of electrical energy has leaded to utilization of more and more Distributed generation (DG) sources in distribution systems. Since the locations and capacities of the DG sources connected to the dist...
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ISBN:
(纸本)9781479987252
Increasing demand of electrical energy has leaded to utilization of more and more Distributed generation (DG) sources in distribution systems. Since the locations and capacities of the DG sources connected to the distribution system profoundly impact on reducing system loss and improving system reliability, so placement and sizing indication of DGs is the most substantial process in distribution systems. By adding the reliability objective to this problem, it becomes more complicated than before and it needs to be solved with an accurate algorithm. To this reason, to solve the proposed problem a new approach based on the mixture of two algorithms named as Particle Swarm Optimization (PSO) and the shuffle frog leaping algorithm (SFLA) is applied in this paper. A meticulous performance analysis is fulfilled on a 33-bus system in order to demonstrate the effectiveness of the presented methodology.
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