Multi-strategy

  • 文章类型: Journal Article
    对算法更新方程的改进是最改进的技术之一。由于缺乏搜索能力,均衡优化器(EO)在求解复杂优化问题时计算复杂度高,可操作性差,本文提出了一种改进的EO,即综合环氧乙烷(MS-EO)更新的多策略。
    首先,在EO中采用了简化的更新策略,以提高可操作性并降低计算复杂度。其次,信息共享策略在简化的EO中使用动态调整策略更新早期迭代阶段的浓度,以形成简化的共享EO(SS-EO)并增强勘探能力。第三,利用迁移策略和黄金分割策略对黄金粒子进行更新,构造黄金SS-EO(GS-EO),提高搜索能力。最后,对后期最差的粒子更新实施精英学习策略,形成MS-EO,增强开发能力。这些策略被嵌入到EO中,通过充分发挥各自的优势,在勘探与开发之间取得平衡。
    来自CEC2013和CEC2017测试集的复杂函数的实验结果表明,MS-EO在搜索能力方面优于EO和相当多最先进的算法,运行速度和可操作性。在多个数据集上进行特征选择的实验结果表明,MS-EO还提供了更多的优势。
    UNASSIGNED: Improvement on the updating equation of an algorithm is among the most improving techniques. Due to the lack of search ability, high computational complexity and poor operability of equilibrium optimizer (EO) in solving complex optimization problems, an improved EO is proposed in this article, namely the multi-strategy on updating synthetized EO (MS-EO).
    UNASSIGNED: Firstly, a simplified updating strategy is adopted in EO to improve operability and reduce computational complexity. Secondly, an information sharing strategy updates the concentrations in the early iterative stage using a dynamic tuning strategy in the simplified EO to form a simplified sharing EO (SS-EO) and enhance the exploration ability. Thirdly, a migration strategy and a golden section strategy are used for a golden particle updating to construct a Golden SS-EO (GS-EO) and improve the search ability. Finally, an elite learning strategy is implemented for the worst particle updating in the late stage to form MS-EO and strengthen the exploitation ability. The strategies are embedded into EO to balance between exploration and exploitation by giving full play to their respective advantages.
    UNASSIGNED: Experimental results on the complex functions from CEC2013 and CEC2017 test sets demonstrate that MS-EO outperforms EO and quite a few state-of-the-art algorithms in search ability, running speed and operability. The experimental results of feature selection on several datasets show that MS-EO also provides more advantages.
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  • 文章类型: Journal Article
    2-KGA,合成维生素C的前体,目前在中国采用“两步发酵”技术生产。然而,这种方法表现出许多固有的约束。本研究提出了一种综合的代谢工程策略,以建立和优化恶臭假单胞菌KT2440中D-山梨糖醇的一步2-KGA发酵工艺。总的来说,筛选内源启动子以鉴定启动子P1用于随后在KT2440中的异源基因表达。在筛选和确认合适的异源基因元件如sldh后,sdh,cytcc551,pqqAB,还有irre,在KT2440中进行基因重组.与最初在KT2440中仅表达sldh和sdh的结果相比,仅获得0.42g/L的产量。然而,通过实施四种代谢工程策略,重组菌株KT20的生产2-KGA的能力显着提高,产量高达6.5g/L,提高了15.48倍。
    2-KGA, a precursor for the synthesis of Vitamin C, is currently produced in China utilizing the \"two-step fermentation\" technique. Nevertheless, this method exhibits many inherent constraints. This study presents a comprehensive metabolic engineering strategy to establish and optimize a one-step 2-KGA fermentation process from D-sorbitol in Pseudomonas putida KT2440. In general, the endogenous promoters were screened to identify promoter P1 for subsequent heterologous gene expression in KT2440. Following the screening and confirmation of suitable heterologous gene elements such as sldh, sdh, cytc551, pqqAB, and irrE, genetic recombination was performed in KT2440. In comparison to the initial achievement of expressing only sldh and sdh in KT2440, a yield of merely 0.42 g/L was obtained. However, by implementing four metabolic engineering strategies, the recombinant strain KT20 exhibited a significant enhancement in its ability to produce 2-KGA with a remarkable yield of up to 6.5 g/L - representing an impressive 15.48-fold improvement.
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  • 文章类型: Journal Article
    在本文中,引入综合学习算法,提出了一种多策略自适应综合学习粒子群优化算法,多种群并行,和参数自适应。在提出的算法中,多种群并行策略旨在改善种群多样性并加速融合。实现了种群粒子交换和变异,保证了粒子间的信息共享。然后,将全局最优值添加到速度更新中,设计了一种新的速度更新策略,以提高局部搜索能力。综合学习策略用于构建学习样本,从而有效促进信息交流,避免陷入局部极值。通过线性改变学习因素,制定了新的因素调整策略,以增强全球搜索能力,并开发了一种基于S形递减函数的自适应惯性权重调整策略,以平衡搜索能力。最后,选择了一些基准函数和光伏参数优化。所提出的算法在10个函数中的6个上获得最佳性能。结果表明,所提出的算法具有较好的多样性,解决方案的准确性,与粒子群算法和其他算法的一些变体相比,搜索能力强。为光伏复杂的工程问题提供了更有效的参数组合,从而提高能量转换效率。
    In this paper, a multi-strategy adaptive comprehensive learning particle swarm optimization algorithm is proposed by introducing the comprehensive learning, multi-population parallel, and parameter adaptation. In the proposed algorithm, a multi-population parallel strategy is designed to improve population diversity and accelerate convergence. The population particle exchange and mutation are realized to ensure information sharing among the particles. Then, the global optimal value is added to velocity update to design a new velocity update strategy for improving the local search ability. The comprehensive learning strategy is employed to construct learning samples, so as to effectively promote the information exchange and avoid falling into local extrema. By linearly changing the learning factors, a new factor adjustment strategy is developed to enhance the global search ability, and a new adaptive inertia weight-adjustment strategy based on an S-shaped decreasing function is developed to balance the search ability. Finally, some benchmark functions and the parameter optimization of photovoltaics are selected. The proposed algorithm obtains the best performance on 6 out of 10 functions. The results show that the proposed algorithm has greatly improved diversity, solution accuracy, and search ability compared with some variants of particle swarm optimization and other algorithms. It provides a more effective parameter combination for the complex engineering problem of photovoltaics, so as to improve the energy conversion efficiency.
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  • 文章类型: Journal Article
    The real-time location of pollution sources is the process of inverting pollution sources based on the dynamic optimization model constructed by the time-varying pollution concentration detected by the water quality sensor. Due to the vast quantities of the water supply networks, the water quality sensors will only be placed on critical nodes, resulting in multiple solutions. However, the increased monitoring data enhances the uniqueness of the solution. Combined with the real-time location of pollution sources, this work proposed a multi-strategy dynamic multi-mode optimization algorithm based on domain knowledge, which could guide the population search and avoid trapped into local optimal. The merging mechanism was used to keep the diversity of the population and prevent sub-population clustering on the same optimal solution. The simulation results showed that the algorithm could effectively solve the real-time location problem of pollution sources in different pipe networks and pollution scenarios.
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  • 文章类型: Journal Article
    Nicotinamide adenine dinucleotide (NAD+) is an essential coenzyme involved in numerous physiological processes. As an attractive product in the industrial field, NAD+ also plays an important role in oxidoreductase-catalyzed reactions, drug synthesis, and the treatment of diseases, such as dementia, diabetes, and vascular dysfunction. Currently, although the biotechnology to construct NAD+-overproducing strains has been developed, limited regulation and low productivity still hamper its use on large scales. Here, we describe multi-strategy metabolic engineering to address the NAD+-production bottleneck in E. coli. First, blocking the degradation pathway of NAD(H) increased the accumulation of NAD+ by 39%. Second, key enzymes involved in the Preiss-Handler pathway of NAD+ synthesis were overexpressed and led to a 221% increase in the NAD+ concentration. Third, the PRPP synthesis module and Preiss-Handler pathway were combined to strengthen the precursors supply, which resulted in enhancement of NAD+ content by 520%. Fourth, increasing the ATP content led to an increase in the concentration of NAD+ by 170%. Finally, with the combination of all above strategies, a strain with a high yield of NAD+ was constructed, with the intracellular NAD+ concentration reaching 26.9 μmol/g DCW, which was 834% that of the parent strain. This study presents an efficient design of an NAD+-producing strain through global regulation metabolic engineering.
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