evolutionary algorithm

进化算法
  • 文章类型: Journal Article
    神经网络修剪是降低深度神经网络计算复杂度的流行方法。近年来,随着越来越多的证据表明,传统的网络修剪方法采用了不适当的代理度量,随着新型硬件越来越多,在网络修剪的循环中结合硬件特性的硬件感知网络修剪已获得越来越多的关注。网络精度和硬件效率(延迟、内存消耗,等。)是网络修剪成功的关键目标,但是多个目标之间的冲突使得不可能找到一个最优解。以前的研究大多将硬件感知的网络修剪转换为具有单一目标的优化问题。在本文中,我们建议使用多目标进化算法(MOEA)来解决硬件感知的网络修剪问题。具体来说,我们将问题表述为多目标优化问题,并提出了一个新颖的模因MOEA,即HAMP,结合了有效的基于投资组合的选择和代理辅助的本地搜索,来解决它。实证研究表明,与最先进的硬件感知网络修剪方法相比,MOEA在同时提供一组替代解决方案方面的潜力以及HAMP的优越性。
    Neural network pruning is a popular approach to reducing the computational complexity of deep neural networks. In recent years, as growing evidence shows that conventional network pruning methods employ inappropriate proxy metrics, and as new types of hardware become increasingly available, hardware-aware network pruning that incorporates hardware characteristics in the loop of network pruning has gained growing attention. Both network accuracy and hardware efficiency (latency, memory consumption, etc.) are critical objectives to the success of network pruning, but the conflict between the multiple objectives makes it impossible to find a single optimal solution. Previous studies mostly convert the hardware-aware network pruning to optimization problems with a single objective. In this paper, we propose to solve the hardware-aware network pruning problem with Multi-Objective Evolutionary Algorithms (MOEAs). Specifically, we formulate the problem as a multi-objective optimization problem, and propose a novel memetic MOEA, namely HAMP, that combines an efficient portfolio-based selection and a surrogate-assisted local search, to solve it. Empirical studies demonstrate the potential of MOEAs in providing simultaneously a set of alternative solutions and the superiority of HAMP compared to the state-of-the-art hardware-aware network pruning method.
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  • 文章类型: Journal Article
    约束多目标优化问题(CMaOP)在各个领域逐渐出现,对该领域具有重要意义。这些问题通常涉及复杂的帕累托边界(PFs),既精致又不均衡,从而使他们的解决方案变得困难和具有挑战性。传统算法倾向于优先考虑收敛,导致决策变量过早收敛,这大大降低了找到受约束的帕累托边界(CPF)的可能性。这导致整体性能差。为了应对这一挑战,我们的解决方案涉及一种基于参考点和角度缓和策略(dCMaOEA-RAE)的新颖的双种群约束多目标进化算法。它依赖于利用参考点和角度的宽松选择策略,通过保留当前可能表现不佳但对整体优化过程有积极贡献的解决方案来促进双种群之间的合作。我们能够引导种群及时移向最优可行解区域,以获得一系列优越的解才能获得。通过对77个测试问题进行的实验结果,证明了我们提出的算法在所有三个评估指标上的竞争力。与其他十种尖端算法的比较进一步验证了其有效性。
    Constrained many-objective optimization problems (CMaOPs) have gradually emerged in various areas and are significant for this field. These problems often involve intricate Pareto frontiers (PFs) that are both refined and uneven, thereby making their resolution difficult and challenging. Traditional algorithms tend to over prioritize convergence, leading to premature convergence of the decision variables, which greatly reduces the possibility of finding the constrained Pareto frontiers (CPFs). This results in poor overall performance. To tackle this challenge, our solution involves a novel dual-population constrained many-objective evolutionary algorithm based on reference point and angle easing strategy (dCMaOEA-RAE). It relies on a relaxed selection strategy utilizing reference points and angles to facilitate cooperation between dual populations by retaining solutions that may currently perform poorly but contribute positively to the overall optimization process. We are able to guide the population to move to the optimal feasible solution region in a timely manner in order to obtain a series of superior solutions can be obtained. Our proposed algorithm\'s competitiveness across all three evaluation indicators was demonstrated through experimental results conducted on 77 test problems. Comparisons with ten other cutting-edge algorithms further validated its efficacy.
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  • 文章类型: Journal Article
    背景:多症是一个重要的公共卫生问题,以多种先前存在的医疗状况共存和相互作用为特征。这种复杂的情况与COVID-19的风险增加有关。感染COVID-19的多病患者通常面临预期寿命的显著降低。大流行后时期也凸显了虚弱的增加,强调将现有多发病率细节纳入流行病学风险评估的重要性。管理包括病史在内的临床数据面临重大挑战,特别是由于多症条件的稀有性所产生的数据的稀疏性。此外,组合多发病率特征的复杂列举引入了与组合爆炸相关的挑战。
    目的:本研究旨在评估患有多种疾病的个体中COVID-19的严重程度,考虑到他们的人口特征,如年龄和性别。我们提出了一种进化机器学习模型,旨在处理稀疏性,根据COVID-19住院患者的病史分析其先前存在的多患病情况。我们的目标是确定与COVID-19严重程度密切相关的多发病率特征组合的最佳集合。我们还将Apriori算法应用于这些进化推导的预测特征组合,以识别具有高支持度的特征。
    方法:我们使用了来自皮埃蒙特3个行政来源的数据,意大利,涉及12,793名年龄在45-74岁之间的人,他们在2020年2月至5月之间检测出COVID-19阳性。根据他们在COVID-19之前的5年病史,我们提取了多浊度特征,包括药物处方,疾病诊断,性别,和年龄。关注COVID-19住院,我们根据年龄和性别将数据分为4个队列.通过随机重采样解决数据不平衡,我们比较了各种机器学习算法,以确定进化方法的最佳分类模型。使用5倍交叉验证,我们评估了每个模型的性能。我们的进化算法,利用深度学习分类器,生成基于预测的适合度评分,以确定与COVID-19住院风险相关的多发病率组合。最终,Apriori算法用于识别高支持度的频繁组合。
    结果:我们确定了与COVID-19住院相关的多发病率预测因子,表明COVID-19结果更严重。最终进化组合中经常出现的发病特征是年龄>53,R03BA(糖皮质激素吸入剂),和N03AX(其他抗癫痫药)在队列1中;A10BA(双胍或二甲双胍)和N02BE(苯胺)在队列2中;N02AX(其他阿片类药物)和M04AA(抑制尿酸产生的制剂)在队列3中;G04CA(α-肾上腺素受体拮抗剂)在队列4中。
    结论:当与其他多浊度特征结合使用时,甚至不那么普遍的医疗条件显示与结果的关联。这项研究提供了超越COVID-19的见解,证明了如何调整重新利用的行政数据,并有助于加强对弱势群体的风险评估。
    BACKGROUND: Multimorbidity is a significant public health concern, characterized by the coexistence and interaction of multiple preexisting medical conditions. This complex condition has been associated with an increased risk of COVID-19. Individuals with multimorbidity who contract COVID-19 often face a significant reduction in life expectancy. The postpandemic period has also highlighted an increase in frailty, emphasizing the importance of integrating existing multimorbidity details into epidemiological risk assessments. Managing clinical data that include medical histories presents significant challenges, particularly due to the sparsity of data arising from the rarity of multimorbidity conditions. Also, the complex enumeration of combinatorial multimorbidity features introduces challenges associated with combinatorial explosions.
    OBJECTIVE: This study aims to assess the severity of COVID-19 in individuals with multiple medical conditions, considering their demographic characteristics such as age and sex. We propose an evolutionary machine learning model designed to handle sparsity, analyzing preexisting multimorbidity profiles of patients hospitalized with COVID-19 based on their medical history. Our objective is to identify the optimal set of multimorbidity feature combinations strongly associated with COVID-19 severity. We also apply the Apriori algorithm to these evolutionarily derived predictive feature combinations to identify those with high support.
    METHODS: We used data from 3 administrative sources in Piedmont, Italy, involving 12,793 individuals aged 45-74 years who tested positive for COVID-19 between February and May 2020. From their 5-year pre-COVID-19 medical histories, we extracted multimorbidity features, including drug prescriptions, disease diagnoses, sex, and age. Focusing on COVID-19 hospitalization, we segmented the data into 4 cohorts based on age and sex. Addressing data imbalance through random resampling, we compared various machine learning algorithms to identify the optimal classification model for our evolutionary approach. Using 5-fold cross-validation, we evaluated each model\'s performance. Our evolutionary algorithm, utilizing a deep learning classifier, generated prediction-based fitness scores to pinpoint multimorbidity combinations associated with COVID-19 hospitalization risk. Eventually, the Apriori algorithm was applied to identify frequent combinations with high support.
    RESULTS: We identified multimorbidity predictors associated with COVID-19 hospitalization, indicating more severe COVID-19 outcomes. Frequently occurring morbidity features in the final evolved combinations were age>53, R03BA (glucocorticoid inhalants), and N03AX (other antiepileptics) in cohort 1; A10BA (biguanide or metformin) and N02BE (anilides) in cohort 2; N02AX (other opioids) and M04AA (preparations inhibiting uric acid production) in cohort 3; and G04CA (Alpha-adrenoreceptor antagonists) in cohort 4.
    CONCLUSIONS: When combined with other multimorbidity features, even less prevalent medical conditions show associations with the outcome. This study provides insights beyond COVID-19, demonstrating how repurposed administrative data can be adapted and contribute to enhanced risk assessment for vulnerable populations.
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  • 文章类型: Journal Article
    自然游泳者和飞行者可以通过改变冲程力学从灾难性的推进器损伤中完全恢复:一些鱼甚至可以失去76%的推进表面而不会失去推力。我们考虑应用这些原理来使机器人拍打推进器能够自动修复功能。然而,由于不相关的进化压力,将这些改变从生物体直接转移到机器人拍打推进器可能不是最佳选择。相反,我们使用机器学习技术将这些变化与机器人系统的最佳变化进行比较。我们实现了一个硬件在环的在线人工进化,用柔性板进行实验评估。为了收回推力,学习的策略增加了幅度,频率和攻角(AOA)振幅,和相移AOA约110°。大多数鱼类文献报道仅振幅增加。当恢复侧向力时,我们发现力的方向与AOA相关。没有明确的振幅或频率趋势,而频率在大多数昆虫文献中增加。这些结果表明,机械拍打推进器如何最有效地适应损坏可能无法与自然游泳者和飞行者保持一致。
    Natural swimmers and flyers can fully recover from catastrophic propulsor damage by altering stroke mechanics: some fish can lose even 76% of their propulsive surface without loss of thrust. We consider applying these principles to enable robotic flapping propulsors to autonomously repair functionality. However, direct transference of these alterations from an organism to a robotic flapping propulsor may be suboptimal owing to irrelevant evolutionary pressures. Instead, we use machine learning techniques to compare these alterations with those optimal for a robotic system. We implement an online artificial evolution with hardware-in-the-loop, performing experimental evaluations with a flexible plate. To recoup thrust, the learned strategy increased amplitude, frequency and angle of attack (AOA) amplitude, and phase-shifted AOA by approximately 110°. Only amplitude increase is reported by most fish literature. When recovering side force, we find that force direction is correlated with AOA. No clear amplitude or frequency trend is found, whereas frequency increases in most insect literature. These results suggest that how mechanical flapping propulsors most efficiently adjust to damage may not align with natural swimmers and flyers.
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  • 文章类型: Journal Article
    作为工程领域,能源,地质变得越来越复杂,决策者面临不断升级的挑战,需要熟练的解决方案来满足实际生产需求。进化算法,受到生物进化的启发,已经成为解决复杂优化问题而不依赖于梯度数据的强大方法。其中,树种子算法(TSA)由于其独特的机制和有效的搜索能力而与众不同。然而,其开发和勘探阶段之间的不平衡可能导致其陷入局部最优,阻碍全局最优解的发现。本研究引入了一种改进的TSA,该TSA结合了水循环和量子旋转门机制。这些增强功能有助于算法摆脱局部峰值并在其开发和勘探阶段之间实现更和谐的平衡。比较实验评估,使用CEC2017基准和著名的元启发式算法,证明了升级后的算法具有更快的收敛速度和增强的全局最优定位能力。此外,它在优化油藏生产模型中的应用强调了其与竞争方法相比的优越性,进一步验证其真实世界的优化能力。
    As the fields of engineering, energy, and geology become increasingly complex, decision makers face escalating challenges that require skilled solutions to meet practical production needs. Evolutionary algorithms, inspired by biological evolution, have emerged as powerful methods for tackling intricate optimization problems without relying on gradient data. Among these, the tree-seed algorithm (TSA) distinguishes itself due to its unique mechanism and efficient searching capabilities. However, an imbalance between its exploitation and exploration phases can lead it to be stuck in local optima, impeding the discovery of globally optimal solutions. This study introduces an improved TSA that incorporates water-cycling and quantum rotation-gate mechanisms. These enhancements assist the algorithm in escaping local peaks and achieving a more harmonious balance between its exploitation and exploration phases. Comparative experimental evaluations, using the CEC 2017 benchmarks and a well-known metaheuristic algorithm, demonstrate the upgraded algorithm\'s faster convergence rate and enhanced ability to locate global optima. Additionally, its application in optimizing reservoir production models underscores its superior performance compared to competing methods, further validating its real-world optimization capabilities.
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  • 文章类型: Journal Article
    围攻算法在单目标优化问题中表现出优异的性能。然而,关于多目标优化问题的BCA算法研究还没有文献。因此,本文提出了一种新的多目标围攻算法来解决多目标优化问题。网格机制,归档机制,并将领导者选择机制集成到BCA中,以估计Pareto最优解并逼近Pareto最优边界。用MOPSO对所提出的算法进行了测试,MOEA/D,和NSGAIII关于基准函数IMOP和ZDT。实验结果表明,该算法在Pareto最优解的准确性方面可以获得有竞争力的结果。
    The besiege and conquer algorithm has shown excellent performance in single-objective optimization problems. However, there is no literature on the research of the BCA algorithm on multi-objective optimization problems. Therefore, this paper proposes a new multi-objective besiege and conquer algorithm to solve multi-objective optimization problems. The grid mechanism, archiving mechanism, and leader selection mechanism are integrated into the BCA to estimate the Pareto optimal solution and approach the Pareto optimal frontier. The proposed algorithm is tested with MOPSO, MOEA/D, and NSGAIII on the benchmark function IMOP and ZDT. The experiment results show that the proposed algorithm can obtain competitive results in terms of the accuracy of the Pareto optimal solution.
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  • 文章类型: Journal Article
    背景:药物设计是一项具有挑战性的重要任务,需要产生能够与特定蛋白质靶标结合的新型有效分子。人工智能算法最近显示出加快药物设计过程的潜力。然而,现有方法采用多目标方法,限制了目标的数量。
    结果:在本文中,我们从多客观的角度扩展了这一研究思路,通过提出一种新颖的框架,该框架集成了基于潜在变压器的分子生成模型,结合吸收的药物设计系统,分布,新陈代谢,排泄,和毒性预测,分子对接,和多目标元启发式。我们比较了两种潜在的Transformer模型(ReLSO和FragNet)在分子生成任务上的性能,并表明ReLSO在重建和潜在空间组织方面优于FragNet。然后,我们基于进化算法和粒子群优化,探索了六种不同的多目标元启发式方法,用于涉及人类溶血磷脂酸受体1(癌症相关蛋白靶标)的潜在候选药物的药物设计任务。
    结论:我们表明,基于优势和分解的多目标进化算法在找到满足许多目标的分子方面表现最佳,如高结合亲和力和低毒性,和高度的药物相似性。我们的框架展示了将变形金刚和多目标计算智能相结合用于药物设计的潜力。
    BACKGROUND: Drug design is a challenging and important task that requires the generation of novel and effective molecules that can bind to specific protein targets. Artificial intelligence algorithms have recently showed promising potential to expedite the drug design process. However, existing methods adopt multi-objective approaches which limits the number of objectives.
    RESULTS: In this paper, we expand this thread of research from the many-objective perspective, by proposing a novel framework that integrates a latent Transformer-based model for molecular generation, with a drug design system that incorporates absorption, distribution, metabolism, excretion, and toxicity prediction, molecular docking, and many-objective metaheuristics. We compared the performance of two latent Transformer models (ReLSO and FragNet) on a molecular generation task and show that ReLSO outperforms FragNet in terms of reconstruction and latent space organization. We then explored six different many-objective metaheuristics based on evolutionary algorithms and particle swarm optimization on a drug design task involving potential drug candidates to human lysophosphatidic acid receptor 1, a cancer-related protein target.
    CONCLUSIONS: We show that multi-objective evolutionary algorithm based on dominance and decomposition performs the best in terms of finding molecules that satisfy many objectives, such as high binding affinity and low toxicity, and high drug-likeness. Our framework demonstrates the potential of combining Transformers and many-objective computational intelligence for drug design.
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  • 文章类型: Journal Article
    用于疾病诊断的治疗靶标或生物标志物的肽的开发是蛋白质工程中的挑战性任务。目前的方法很乏味,由于需要考虑巨大的搜索空间,因此通常耗时且需要复杂的实验室数据。计算机方法可以加速研究并大大降低成本。进化算法是探索大型搜索空间的有前途的方法,可以促进新肽的发现。本研究提出了基于遗传编程的POET算法的新变体的开发和使用,叫做POETRegex,其中个人由正则表达式列表表示。该算法在小的经策划的数据集上进行训练,并用于产生新的肽,以提高肽在具有化学交换饱和转移(CEST)的磁共振成像中的灵敏度。所得到的模型比初始POET模型实现20%的性能增益,并且能够预测与金标准肽相比具有58%性能提高的候选肽。通过将遗传编程的强大功能与正则表达式的灵活性相结合,鉴定了新的肽靶,提高了CEST检测的灵敏度.该方法为有效鉴定具有治疗或诊断潜力的肽提供了有希望的研究方向。
    The development of peptides for therapeutic targets or biomarkers for disease diagnosis is a challenging task in protein engineering. Current approaches are tedious, often time-consuming and require complex laboratory data due to the vast search spaces that need to be considered. In silico methods can accelerate research and substantially reduce costs. Evolutionary algorithms are a promising approach for exploring large search spaces and can facilitate the discovery of new peptides. This study presents the development and use of a new variant of the genetic-programming-based POET algorithm, called POET Regex , where individuals are represented by a list of regular expressions. This algorithm was trained on a small curated dataset and employed to generate new peptides improving the sensitivity of peptides in magnetic resonance imaging with chemical exchange saturation transfer (CEST). The resulting model achieves a performance gain of 20% over the initial POET models and is able to predict a candidate peptide with a 58% performance increase compared to the gold-standard peptide. By combining the power of genetic programming with the flexibility of regular expressions, new peptide targets were identified that improve the sensitivity of detection by CEST. This approach provides a promising research direction for the efficient identification of peptides with therapeutic or diagnostic potential.
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  • 文章类型: Journal Article
    We study the (1:s+1) success rule for controlling the population size of the (1,λ)- EA. It was shown by Hevia Fajardo and Sudholt that this parameter control mechanism can run into problems for large s if the fitness landscape is too easy. They conjectured that this problem is worst for the ONEMAX benchmark, since in some well-established sense ONEMAX is known to be the easiest fitness landscape. In this paper we disprove this conjecture. We show that there exist s and ɛ such that the self-adjusting (1,λ)-EA with the (1:s+1)-rule optimizes ONEMAX efficiently when started with ɛn zero-bits, but does not find the optimum in polynomial time on DYNAMIC BINVAL. Hence, we show that there are landscapes where the problem of the (1:s+1)-rule for controlling the population size of the (1,λ)-EA is more severe than for ONEMAX. The key insight is that, while ONEMAX is the easiest function for decreasing the distance to the optimum, it is not the easiest fitness landscape with respect to finding fitness-improving steps.
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  • 文章类型: Journal Article
    The fitness level method is a popular tool for analyzing the hitting time of elitist evolutionary algorithms. Its idea is to divide the search space into multiple fitness levels and estimate lower and upper bounds on the hitting time using transition probabilities between fitness levels. However, the lower bound generated by this method is often loose. An open question regarding the fitness level method is what are the tightest lower and upper time bounds that can be constructed based on transition probabilities between fitness levels. To answer this question, we combine drift analysis with fitness levels and define the tightest bound problem as a constrained multi-objective optimization problem subject to fitness levels. The tightest metric bounds by fitness levels are constructed and proven for the first time. Then linear bounds are derived from metric bounds and a framework is established that can be used to develop different fitness level methods for different types of linear bounds. The framework is generic and promising, as it can be used to draw tight time bounds on both fitness landscapes with and without shortcuts. This is demonstrated in the example of the (1+1) EA maximizing the TwoMax1 function.
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