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Few More Series of Reciprocals with Binomial Coefficients and Their Evaluations 更多具有二项式系数的倒数数列及其求值
4区 工程技术 Q1 Mathematics Pub Date : 2024-01-16 DOI: 10.1155/2024/6640697
Shruthi C. Bhat, M. Krithi, B. R. Srivatsa Kumar
In the present work, utilizing the known series, new series involving reciprocals of binomial coefficients, alternating positive, and negative binomial coefficients are constructed. Further, several new series of reciprocals of binomial coefficients with two odd terms in the denominator are obtained. In the end, we use these to establish the closed form evaluations of hypergeometric functions for the argument 1/16.
本研究利用已知数列,构建了涉及二项式系数倒数、交替正二项式系数和负二项式系数的新数列。此外,我们还得到了分母中有两个奇数项的二项式系数倒数的几个新数列。最后,我们利用这些方法建立了参数 1/16 的超几何函数的封闭式求值。
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引用次数: 0
Splitting Long Event Sequences Drawn from Cyclic Processes for Discovering Workflow Nets 拆分循环流程中的长事件序列以发现工作流程网络
4区 工程技术 Q1 Mathematics Pub Date : 2024-01-03 DOI: 10.1155/2024/7033048
Yolanda Alvarez-Pérez, Ernesto López-Mellado
This paper addresses the preprocessing of event sequences issued from cyclic discrete event processes, which perform activities continuously whose delimitation of jobs or cases is not explicit. The sequences include several occurrences of the same events due to the iterative behaviour, such that discovery methods conceived for workflow nets (WFN) cannot process such sequences. In order to handle this issue, a novel technique for splitting a set of long event traces S = {Sk} (|S| ≥ 1) exhibiting the behaviour of cyclic processes is presented. The aim of this technique is to obtain from S a log λ = {σi} of event traces representing the same behaviour, which can be processed by methods that discover WFN. The procedures derived from this technique have polynomial-time complexity.
本文探讨了如何预处理循环离散事件流程发出的事件序列,这些流程连续执行活动,其工作或案例的划分并不明确。由于迭代行为,这些序列包括相同事件的多次发生,因此为工作流网络(WFN)设计的发现方法无法处理此类序列。为了解决这个问题,我们采用了一种新颖的技术来分割一组长事件轨迹 S = {Sk} 。(|S| ≥ 1) 的新技术。该技术的目的是从 S 中获得代表相同行为的事件轨迹对数 λ = {σi},这些对数可通过发现 WFN 的方法进行处理。由该技术衍生出的程序具有多项式时间复杂性。
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引用次数: 0
Numerical Study of Wax Deposition from Multiphase Flow in Oil Pipelines with Heat and Mass Transfer 石油管道多相流蜡沉积的传热传质数值研究
4区 工程技术 Q1 Mathematics Pub Date : 2023-12-30 DOI: 10.1155/2023/1173505
Francis Oketch Ochieng, Mathew Ngugi Kinyanjui, Phineas Roy Kiogora, Jeconia Okelo Abonyo
Wax deposition in field-scale crude oil pipelines poses a significant challenge to the oil and gas industry, leading to reduced flow rates, increased pressure drops, and potential blockages. Understanding the mechanisms governing wax deposition is crucial for developing effective mitigation strategies. This study investigates the impact of multiphase flow conditions, including water-in-oil emulsion, wax precipitation kinetics, shear dispersion, and molecular diffusion, on wax deposition in field-scale crude oil pipelines. A numerical model is developed that employs second-order semi-implicit temporal discretization schemes, such as Crank–Nicolson and Adams–Bashforth methods, in conjunction with a bivariate spectral collocation scheme using Chebyshev–Gauss–Lobatto grid points. The impact of various flow parameters, including Reynolds number (Re), mass Grashof number (Gr), Schmidt number (Sc), and Weber number (We), on the flow variables, wall shear stress, and heat and mass fluxes are investigated. The numerical simulations demonstrate that flow parameters significantly influence the flow behavior, wall shear stress, wall heat flux, and wall mass flux in waxy crude oil pipelines. Specifically, the aggregation of wax crystals in the pipeline decreases by at most 2.5% with increasing Reynolds number from 2.2361 to 3.1361. Conversely, it increases by at most 3.4% with increasing mass Grashof number from 5 to 11 and by at most 4.8% with increasing Weber number from 1.0 to 2.5. Furthermore, the Nusselt number increases from 1.9907 to 4.9834 with increasing Reynolds number from 2.2361 to 5.2361 and from 1.9907 to 2.0225 with increasing mass Grashof number from 5 to 20. It also increases from 1.9907 to 2.0434 with increasing Weber number from 1.0 to 2.5. The insights gained from this study can be applied to optimize pipeline design, operational parameters, and wax deposition mitigation strategies, leading to enhanced pipeline performance and reduced operational costs. The numerical model developed in this work serves as a valuable tool for simulating and predicting wax deposition behavior under various operating conditions.
蜡沉积在野外规模的原油管道中给石油和天然气行业带来了巨大挑战,导致流速降低、压降增加以及潜在的堵塞。了解蜡沉积的机理对于制定有效的缓解策略至关重要。本研究探讨了油包水乳化液、蜡沉淀动力学、剪切分散和分子扩散等多相流条件对现场规模原油管道中蜡沉积的影响。所开发的数值模型采用了二阶半隐式时间离散方案,如 Crank-Nicolson 和 Adams-Bashforth 方法,并结合使用 Chebyshev-Gauss-Lobatto 网格点的双变量光谱配位方案。研究了各种流动参数(包括雷诺数 (Re)、质量格拉肖夫数 (Gr)、施密特数 (Sc) 和韦伯数 (We))对流动变量、壁面剪应力以及热通量和质量通量的影响。数值模拟结果表明,流动参数对含蜡原油管道中的流动行为、管壁剪应力、管壁热通量和管壁质量通量有显著影响。具体来说,随着雷诺数从 2.2361 增加到 3.1361,管道中蜡晶体的聚集最多会减少 2.5%。相反,随着质量格拉肖夫数从 5 增加到 11,聚集最多增加 3.4%;随着韦伯数从 1.0 增加到 2.5,聚集最多增加 4.8%。此外,随着雷诺数从 2.2361 增加到 5.2361,努赛特数从 1.9907 增加到 4.9834;随着质量格拉肖夫数从 5 增加到 20,努赛特数从 1.9907 增加到 2.0225。随着韦伯数从 1.0 增加到 2.5,它也从 1.9907 增加到 2.0434。从本研究中获得的启示可用于优化管道设计、运行参数和蜡沉积缓解策略,从而提高管道性能并降低运行成本。本研究开发的数值模型是模拟和预测各种运行条件下蜡沉积行为的重要工具。
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引用次数: 0
Stabilization and Discretization of the Coupled Heat and Wave Equations 热方程和波方程耦合的稳定化和离散化
4区 工程技术 Q1 Mathematics Pub Date : 2023-12-27 DOI: 10.1155/2023/8901825
Kun-Yi Yang, Xu Zhang
In this paper, we consider the stabilization of the coupled heat and wave equations under the static feedback or the dynamic feedback. Moreover, we make the coupled systems discretized by using the finite-volume approach, and then we consider the stabilized properties of the discrete systems. First, for the coupled system under the static feedback, it is shown that the system is exponentially stable by using the Lyapunov method, and then the corresponding discrete system can be shown to be exponentially stable by constucting the discretized Lyapunov function. Second, for the coupled system under the dynamic feedback, we also show that both of the system and its discrete scheme are exponentially stable. Third, numerical simulations are given to show the effectiveness of the stable controllers.
本文考虑了热方程和波方程在静态反馈或动态反馈下的稳定问题。此外,我们利用有限体积方法将耦合系统离散化,然后考虑离散系统的稳定化特性。首先,对于静态反馈下的耦合系统,利用李亚普诺夫方法证明系统是指数稳定的,然后通过构造离散化的李亚普诺夫函数可以证明相应的离散系统是指数稳定的。其次,对于动态反馈下的耦合系统,我们也证明了系统及其离散方案都是指数稳定的。第三,我们给出了数值模拟,以显示稳定控制器的有效性。
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引用次数: 0
A Two-Archive Algorithm with Interactive Mechanism for Many-Objective Optimization 带互动机制的多目标优化双卷算法
4区 工程技术 Q1 Mathematics Pub Date : 2023-12-19 DOI: 10.1155/2023/2005465
Shuren Liu, Shuping Li, Changchun Li, Changning Cai, Guojian Cheng
This paper proposes an interactive two-archive method to solve many-objective optimization problems. Two updating strategies based on the aggregation-based framework are presented and incorporated into a two-archive framework. In addition, we further extend this method by introducing an interactive mechanism in which evolutionary information is passed from the diversity archive to the convergence archive. Given the requirement to balance convergence and diversity, a mating selection method is proposed to regulate the evolutionary speed of these two archives collaboratively. The proposed algorithm has been tested extensively on several problems with different peer algorithms to validate its effectiveness. The results show that the proposed method can outperform several state-of-the-art evolutionary algorithms for handling many-objective optimization.
本文提出了一种交互式双档案方法来解决多目标优化问题。本文提出了基于聚合框架的两种更新策略,并将其纳入双档案框架。此外,我们通过引入一种互动机制进一步扩展了这种方法,在这种机制中,演化信息从多样性档案传递到收敛性档案。考虑到平衡收敛性和多样性的要求,我们提出了一种交配选择方法,以协同调节这两个档案的进化速度。为了验证所提算法的有效性,我们在多个问题上用不同的同行算法进行了广泛测试。结果表明,在处理多目标优化方面,所提出的方法优于几种最先进的进化算法。
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引用次数: 0
Detection of Human Stress Using Optimized Feature Selection and Classification in ECG Signals 利用心电信号中的优化特征选择和分类检测人体压力
4区 工程技术 Q1 Mathematics Pub Date : 2023-12-13 DOI: 10.1155/2023/3356347
Narmadha G, Deivasigamani S, Muthukumar Vellaisamy, Lídio Inácio Freitas, Badlishah Ahmad R, Sakthivel B
An autonomic nervous system (ANS) of humans is majorly affected by psychological stress. The changes in ANS may cause several chronic diseases in humans. The electrocardiogram (ECG) signal is used to observe the variation in ANS. Numerous techniques are presented for an ECG stress signal handling feature extraction and classification. This work managed a heart rate variability feature acquired from smaller peak waveforms such as P, Q, S, and T waves. Also, the R peak is detected, which is a significant part of the ECG waveform. In this work, the proposed stress classification work has been categorized into two main processes: feature selection (FS) and classification. The main aim of the proposed work is to propose an optimized FS and classifier model for the detection of stress in ECG signals. The Metaheuristics model of the African vulture optimization (AVO) technique is presented to perform an FS. This selection is made to choose the required features and minimize the data for classification. The AVO-based modified Elman recurrent neural network (MERNN) technique is proposed to perform an efficient classification. The AVO is used for fine-tuning the weight of the MERNN technique. The experimental result of this technique is evaluated in terms of Recall (91.56%), Accuracy (92.43%), Precision (92.78%), and F1 score (95.86%). Thus, the proposed performance achieved a superior result than the conventional techniques.
人类的自律神经系统(ANS)主要受到心理压力的影响。自律神经系统的变化可能导致人类多种慢性疾病。心电图(ECG)信号可用于观察自律神经系统的变化。针对心电图压力信号处理特征提取和分类提出了许多技术。这项工作管理从较小的峰值波形(如 P、Q、S 和 T 波)中获取的心率变异性特征。此外,还检测到了 R 峰,这是心电图波形的重要组成部分。在这项工作中,拟议的压力分类工作主要分为两个过程:特征选择(FS)和分类。这项工作的主要目的是提出一种优化的 FS 和分类器模型,用于检测心电信号中的压力。提出了非洲秃鹫优化(AVO)技术的元启发式模型来执行 FS。这种选择是为了选择所需的特征并尽量减少分类数据。提出了基于 AVO 的修正 Elman 循环神经网络(MERNN)技术,以执行高效分类。AVO 用于微调 MERNN 技术的权重。该技术的实验结果以召回率(91.56%)、准确率(92.43%)、精确率(92.78%)和 F1 分数(95.86%)进行评估。因此,建议的性能比传统技术取得了更优异的结果。
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引用次数: 0
Forecasting Credit Risk of SMEs in Supply Chain Finance Using Bayesian Optimization and XGBoost 利用贝叶斯优化和 XGBoost 预测供应链金融中的中小企业信用风险
4区 工程技术 Q1 Mathematics Pub Date : 2023-12-11 DOI: 10.1155/2023/5609996
Chen Zhang, Xinmiao Zhou
Supply chain finance plays a crucial role as a financing channel for small- and medium-sized enterprises (SMEs). However, issues such as financial problems and credit defaults have led to disruptions in this channel. To address credit risk control in SME financing within the field of supply chain finance, this paper focuses on a sample of 506 equipment manufacturing companies listed on the SME board of the Shenzhen Stock Exchange from 2016 to 2020. Taking into consideration, the overall risks faced by these enterprises, the study establishes seven first-level indicators and identifies 84 candidate second-level indicators. Partial correlation and variance analysis are then used for the first round of indicator screening, followed by the use of a BP neural network for the second round of selection. As a result, a system of 26 indicators for supply chain financial risk is constructed. The XGBoost model is employed to evaluate the constructed risk index system, while SVM and random forest models are used as comparison models. Bayesian optimization is utilized for parameter tuning of the three models. Empirical results demonstrate that the BO-XGBoost model reduces prediction errors in comparison to the control models. Furthermore, statistical tests reveal that the predicted values of the BO-XGBoost model significantly differ from those of the other control models. Compared to other individual models, the BO-XGBoost model exhibits increased accuracy in credit risk prediction and a significant discriminative effect. These findings highlight the effectiveness of constructing an efficient risk indicator system and utilizing Bayesian optimization for parameter tuning in XGBoost to better differentiate between risky and normal enterprises, thereby minimizing default losses. The research results underscore the advantages of employing Bayesian optimization in XGBoost, which can be applied in credit default prediction for SMEs and serves as a valuable tool in financial risk management and control.
供应链融资作为中小企业的融资渠道,发挥着至关重要的作用。然而,财务问题和信贷违约等问题导致了这一渠道的中断。为解决供应链金融领域中小企业融资中的信用风险控制问题,本文以 2016 年至 2020 年在深圳证券交易所中小企业板上市的 506 家装备制造企业为样本。考虑到这些企业面临的整体风险,本研究建立了 7 个一级指标,并确定了 84 个候选二级指标。然后采用偏相关分析和方差分析进行第一轮指标筛选,再利用 BP 神经网络进行第二轮筛选。最终,构建了由 26 个指标组成的供应链财务风险指标体系。采用 XGBoost 模型对构建的风险指标体系进行评估,同时使用 SVM 和随机森林模型作为比较模型。贝叶斯优化法用于三个模型的参数调整。实证结果表明,与对照模型相比,BO-XGBoost 模型减少了预测误差。此外,统计测试表明,BO-XGBoost 模型的预测值与其他控制模型的预测值存在显著差异。与其他单个模型相比,BO-XGBoost 模型提高了信用风险预测的准确性,并具有显著的区分效果。这些研究结果凸显了构建一个高效的风险指标体系并利用贝叶斯优化技术对 XGBoost 进行参数调整的有效性,从而更好地区分风险企业和正常企业,最大限度地减少违约损失。研究结果凸显了在 XGBoost 中采用贝叶斯优化技术的优势,该技术可应用于中小企业信用违约预测,是金融风险管理和控制的重要工具。
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引用次数: 0
Feature Aggregation with Two-Layer Ensemble Framework for Multilingual Speech Emotion Recognition 利用双层集合框架进行特征聚合,实现多语言语音情感识别
4区 工程技术 Q1 Mathematics Pub Date : 2023-12-11 DOI: 10.1155/2023/8837465
Sangho Ough, Sejong Pyo, Taeyong Kim
In this study, we present a framework for improving the accuracy of speech emotion recognition in a multilingual environment. In our prior experiments, where machine learning (ML) models were trained to predict emotions in Korean and then tested in English, as well as vice versa, we observed a dependency on language in emotion recognition, resulting in poor accuracy. We suspect that this may be related to the spectral differences in certain emotions between Korean and English and to the tendency for different formant values to have different acoustic frequencies. For this study, we investigated several different methods, including models with mixed databases, a single database, and bagging, boosting, and voting ML algorithms. Finally, we developed a framework consisting of two branches: one for the aggregation of high-dimensional features from multilingual data and one for a two-layered ensemble framework for emotion classification. In the ensemble framework for Korean and English (EF-KEN), features are extracted and ensemble models are trained, boosted, and evaluated by applying them to different spoken languages (English and Korean). The final experimental result demonstrates a meaningful improvement in an environment with two different languages.
在本研究中,我们提出了一个在多语言环境中提高语音情感识别准确性的框架。在我们之前的实验中,我们对机器学习(ML)模型进行了训练,以预测韩语中的情绪,然后用英语进行测试,反之亦然。我们猜测这可能与韩语和英语中某些情绪的频谱差异有关,也与不同的共振值具有不同声频的趋势有关。在这项研究中,我们研究了几种不同的方法,包括混合数据库模型、单一数据库模型以及袋式算法、提升算法和投票式 ML 算法。最后,我们开发了一个由两个分支组成的框架:一个用于聚合多语言数据的高维特征,另一个用于情感分类的双层集合框架。在韩语和英语的集合框架(EF-KEN)中,我们提取了特征,并对集合模型进行了训练、提升,然后将其应用于不同的口语(英语和韩语)进行评估。最终的实验结果表明,在使用两种不同语言的环境中,情绪分类效果得到了显著改善。
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引用次数: 0
An Energy Efficient Evolutionary Approach for Smart City-Based IoT Applications 基于智慧城市的物联网应用的高能效进化方法
4区 工程技术 Q1 Mathematics Pub Date : 2023-12-07 DOI: 10.1155/2023/9937949
Rashmi Prava Das, Tushar Kanta Samal, Ashish Kr. Luhach
Internet of Things (IoT) has been used in smart cities, agriculture, weather forecasting, smart grids, and waste management. The IoT has huge potential but needs refinement. The paper focuses on lowering IoT sensor power consumption to improve network life. This work selects the best IoT cluster header (CH) to maximize energy consumption. The suggested technique uses particle swarm optimization (PSO) with artificial neural networks (ANNs). The optimal CH in an IoT network cluster was identified by taking into account the number of active nodes, the load, the residual energy, and the cost function. This work compares the suggested method with artificial bee colony, genetic, and adaptive gravity search algorithms. The hybrid solution beats conventional methods.
物联网(IoT)已被用于智慧城市、农业、天气预报、智能电网和废物管理。物联网潜力巨大,但需要完善。本文的重点是降低物联网传感器功耗,提高网络寿命。这项工作选择最佳的物联网簇头(CH),以最大限度地提高能耗。建议的技术使用粒子群优化(PSO)和人工神经网络(ANN)。考虑到活动节点数量、负载、剩余能量和成本函数,确定了物联网网络集群中的最佳 CH。这项工作将建议的方法与人工蜂群、遗传和自适应重力搜索算法进行了比较。混合解决方案优于传统方法。
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引用次数: 0
A Chaotic Multi-Objective Runge–Kutta Optimization Algorithm for Optimized Circuit Design 用于优化电路设计的混沌多目标 Runge-Kutta 优化算法
4区 工程技术 Q1 Mathematics Pub Date : 2023-12-07 DOI: 10.1155/2023/6691214
Owen M. Nyandieka, Davies R. Segera
Circuit design plays a pivotal role in engineering, ensuring the creation of efficient, reliable, and cost-effective electronic devices. The complexity of modern circuit design problems has led to the exploration of multi-objective optimization techniques for circuit design optimization, as traditional optimization tools fall short in handling such problems. While metaheuristic algorithms, especially genetic algorithms, have demonstrated promise, their susceptibility to premature convergence poses challenges. This paper proposes a pioneering approach, the chaotic multi-objective Runge–Kutta algorithm (CMRUN), for circuit design optimization, building upon the Runge–Kutta optimization algorithm. By infusing chaos into the core RUN structure, a refined balance between exploration and exploitation is obtained, critical for addressing complex optimization landscapes, enabling the algorithm to navigate nonlinear and nonconvex optimization challenges effectively. This approach is extended to accommodate multiple objectives, ultimately generating Pareto Fronts for the multiple circuit design goals. The performance of CMRUN is rigorously evaluated against 11 multiobjective algorithms, encompassing 15 benchmark test functions and practical circuit design scenarios. The findings of this study underscore the efficiency and real-world applicability of CMRUN, offering valuable insights for tailoring optimization algorithms to the real-world circuit design challenges.
电路设计在工程学中起着举足轻重的作用,它确保了高效、可靠和经济高效的电子设备的诞生。由于现代电路设计问题的复杂性,传统的优化工具在处理此类问题上存在不足,因此人们开始探索用于电路设计优化的多目标优化技术。虽然元启发式算法,尤其是遗传算法,已显示出良好的前景,但其容易过早收敛的特性也带来了挑战。本文在 Runge-Kutta 优化算法的基础上,提出了一种用于电路设计优化的开创性方法--混沌多目标 Runge-Kutta 算法(CMRUN)。通过将混沌注入 RUN 的核心结构,在探索和利用之间实现了精巧的平衡,这对解决复杂的优化问题至关重要,使该算法能够有效地应对非线性和非凸优化挑战。这种方法可扩展至多个目标,最终为多个电路设计目标生成帕累托前沿(Pareto Fronts)。CMRUN 的性能对照 11 种多目标算法进行了严格评估,包括 15 种基准测试功能和实际电路设计场景。这项研究的结果强调了 CMRUN 的效率和实际应用性,为针对实际电路设计挑战定制优化算法提供了宝贵的见解。
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引用次数: 0
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Mathematical Problems in Engineering
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