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Stagnation point flow of viscous nanofluid towards a shrinking sheet with quadratic buoyancy and thermophoresis influence: convection through porous media 受二次浮力和热泳影响的粘性纳米流体向收缩片的滞留点流动:多孔介质对流
Pub Date : 2024-07-07 DOI: 10.46481/jnsps.2024.1970
Ademola Agunbiade, Usman Abubakar, T. Oyekunle, M. Akolade
This study investigates the dynamics of heat and mass transfer, focusing on the impact of nonlinear convection and thermophoresis in the flow of viscous nanofluid towards a shrinking sheet embedded with a porous matrix. To facilitate understanding of the flow behavior, the study employs similarity variables to simplify the resulting nonlinear partial differential equations. Numerical analysis utilizing the collocation method with Legendre polynomials as basis functions reveals distinct distributions of velocity, temperature, and concentration. The results demonstrate that the dimensionless suction coefficient amplifies nanoparticle volume fraction and momentum along the stretching surface. In addition, an increase in internal frictional force leads to heightened injection of heat energy, accelerates the temperature field, and impedes nanoparticle diffusion due to heat absorption. Elevation of convection terms augments momentum, reduces energy dispersion, and enhances nanoparticle diffusion. Moreover, an increase in the dimensionless Eckert number (Ec) correlates with intensified energy and diminished diffusion concentration of the nanoparticle volume fraction.
本研究探讨了热量和质量传递的动力学,重点是粘性纳米流体流向嵌入多孔基质的收缩薄片时非线性对流和热泳的影响。为了便于理解流动行为,研究采用了相似变量来简化由此产生的非线性偏微分方程。利用 Legendre 多项式作为基函数的配位法进行的数值分析揭示了速度、温度和浓度的不同分布。结果表明,无量纲吸力系数会沿拉伸表面放大纳米粒子的体积分数和动量。此外,内摩擦力的增加导致热能注入增加,加速了温度场,并由于吸热而阻碍了纳米粒子的扩散。对流项的增加会增强动量,减少能量分散,并增强纳米粒子的扩散。此外,无量纲埃克特数(Ec)的增加与纳米粒子体积分数的能量增强和扩散浓度降低相关。
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引用次数: 0
Identifying heterogeneity for increasing the prediction accuracy of machine learning models 识别异质性以提高机器学习模型的预测准确性
Pub Date : 2024-06-16 DOI: 10.46481/jnsps.2024.2058
Paavithashnee Ravi Kumar, Majid Khan Majahar Ali, O. Ibidoja
In recent years, the significance of machine learning in agriculture has surged, particularly in post-harvest monitoring for sustainable aquaculture. Challenges like heterogeneity, irrelevant variables and multicollinearity hinder the implementation of smart monitoring systems. However, this study focuses on investigating heterogeneity among drying parameters that determine the moisture content removal during seaweed drying due to its limited attention, particularly within the field of agriculture. Additionally, a heterogeneity model within machine learning algorithms is proposed to enhance accuracy in predicting seaweed moisture content removal, both before and after the removal of heterogeneity parameters and also after the inclusion of single-eliminated heterogeneity parameters. The dataset consists of 1914 observations with 29 independent variables, but this study narrows down to five: Temperature (T1, T4, T7), Humidity (H5), and Solar Radiation (PY). These variables are interacted up to second-order interactions, resulting in 55 variables. Variance inflation factor and boxplots are employed to identify heterogeneity parameters. Two predictive machine learning models, namely random forest and elastic net are then utilized to identify the 15 and 20 highest important parameters for seaweed moisture content removal. Evaluation metrics (MSE, SSE, MAPE, and R-squared) are used to assess model performance. Results demonstrate that the random forest model outperforms the elastic net model in terms of higher accuracy and lower error, both before and after removing heterogeneity parameters, and even after reintroducing single-eliminated heterogeneity parameters. Notably, the random forest model exhibits higher accuracy before excluding heterogeneity parameters.
近年来,机器学习在农业领域的重要性急剧上升,尤其是在可持续水产养殖的收获后监测方面。异质性、不相关变量和多重共线性等挑战阻碍了智能监测系统的实施。然而,本研究侧重于调查决定海藻干燥过程中水分去除率的干燥参数之间的异质性,因为其关注度有限,尤其是在农业领域。此外,还提出了机器学习算法中的异质性模型,以提高预测海藻含水量去除的准确性,包括去除异质性参数之前和之后,以及纳入单一去除的异质性参数之后。数据集由 1914 个观测值和 29 个自变量组成,但本研究将其缩减为 5 个:温度(T1、T4、T7)、湿度(H5)和太阳辐射(PY)。这些变量的交互作用达到二阶交互作用,从而产生 55 个变量。采用方差膨胀因子和方框图来确定异质性参数。然后利用两种预测性机器学习模型,即随机森林和弹性网,来确定海藻含水量去除中最重要的 15 个和 20 个参数。评估指标(MSE、SSE、MAPE 和 R 平方)用于评估模型性能。结果表明,无论是在去除异质性参数之前还是之后,甚至是在重新引入单一去除的异质性参数之后,随机森林模型在更高的准确度和更低的误差方面都优于弹性网模型。值得注意的是,随机森林模型在剔除异质性参数之前表现出更高的准确性。
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引用次数: 0
Throughflow effect on bi-disperse convection in Rivlin-Ericksen fluid 里夫林-埃里克森流体中双分散对流的通流效应
Pub Date : 2024-06-04 DOI: 10.46481/jnsps.2024.2052
P. Sharma, Deepak Bains Sharma, Dr Pankaj Thakur
In this investigation, we delve into the influence of throughflow on the phenomenon of bi-disperse convection within Rivlin-Ericksen fluid. In the context of examining bi-disperse convection within this specific type of fluid, the throughflow effect is considered to have a uniform vertical distribution. The primary focus of this study centers on evaluating the system’s linear stability. To achieve this, we employ normal mode analysis to compute the Darcy-Rayleigh number at the onset of convection. This Darcy-Rayleigh number is computed for both stationary and oscillatory convection modes. Furthermore, we conduct a comprehensive analysis and present the results in graphical form to illustrate the impact of various parameters, including Peclet number and kinematic viscoelastic parameter, on both stationary and oscillatory convection. Our research findings demonstrate that when Peclet number Pr1 < 0, it leads to destabilising effect on both stationary and oscillatory convections. Conversely, when Peclet number Pr1 > 0, it induces stabilising effect on both stationary as well as oscillatory convections.
在本研究中,我们深入探讨了里夫林-埃里克森流体中的贯通流对双分散对流现象的影响。在研究这种特定类型流体中的双分散对流时,我们认为通流效应具有均匀的垂直分布。本研究的主要重点是评估系统的线性稳定性。为此,我们采用法模分析法计算对流开始时的达西-雷利数。该达西-雷利数是针对静止和振荡对流模式计算得出的。此外,我们还进行了综合分析,并以图表形式展示了结果,以说明各种参数(包括佩克莱特数和运动粘弹性参数)对静止对流和振荡对流的影响。我们的研究结果表明,当佩克莱特数 Pr1 < 0 时,会对静止对流和振荡对流产生破坏稳定的影响。相反,当佩克莱特数 Pr1 > 0 时,则会对静止对流和振荡对流产生稳定作用。
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引用次数: 0
The dynamics of hybrid-immune and immunodeficient susceptible individuals and the three stages of COVID-19 vaccination 混合免疫和免疫缺陷易感个体的动态变化以及 COVID-19 疫苗接种的三个阶段
Pub Date : 2024-06-04 DOI: 10.46481/jnsps.2024.2001
E. A. Nwaibeh, M. K. M. Ali, M. O. Adewole
The World Health Organization has disclosed that the hybrid-immune and immunodeficient individuals are two distinct classes of individuals susceptible to the COVID-19 virus. To model this unique characteristics of two distinct categories of susceptible individuals and the dynamics of the three phases of a vaccination program implemented by the World Health Organization in Malaysia, which have not been accounted for in previous studies, a twelve compartmental SSVEIHQR-D epidemiological model was developed. This model aimed to accurately capture the spread of the COVID-19 virus by fitting real-life  data to the model and obtaining updated estimates of the reproduction number. The study also focused on assessing current control measures and exploring strategies to eradicate the virus and mitigate future outbreaks. Mathematical analyses of the model included investigations into stability, equilibrium points, the basic reproduction number R0, optimal control strategies, and sensitivity analyses. Estimation and fitting of the model parameters were conducted using daily situation reports from the Ministry of Health of Malaysia. The obtained value of the basic reproduction number, based on fitted parameter values, indicated stability and reflected the current pandemic situation more realistically. Additionally, the herd immunity threshold was calculated and interpreted in the context of the study findings. Finally, practical insights and recommendations derived from the model’s results were provided to inform government agencies, public health organizations, and intervention bodies, aimed at controlling the spread of the COVID-19 virus.
世界卫生组织披露,混合免疫个体和免疫缺陷个体是两类不同的 COVID-19 病毒易感个体。为了模拟世界卫生组织在马来西亚实施的疫苗接种计划的三个阶段中两类不同的易感人群的独特特征和动态变化,我们开发了一个十二区 SSVEIHQR-D 流行病学模型。该模型旨在通过将现实生活中的数据拟合到模型中,并获得最新的繁殖数量估计值,从而准确捕捉 COVID-19 病毒的传播情况。研究还重点评估了当前的控制措施,并探讨了根除病毒和减少未来爆发的策略。对模型的数学分析包括对稳定性、平衡点、基本繁殖数 R0、最佳控制策略和敏感性分析的研究。模型参数的估算和拟合使用了马来西亚卫生部的每日情况报告。根据拟合参数值得到的基本繁殖数值显示了稳定性,并更真实地反映了当前的疫情。此外,还根据研究结果计算并解释了群体免疫阈值。最后,从模型结果中得出的实用见解和建议为政府机构、公共卫生组织和干预机构提供了信息,旨在控制 COVID-19 病毒的传播。
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引用次数: 0
Constructive approach and randomization of a two-parameter chaos system for securing data 用于数据安全的双参数混沌系统的建设性方法和随机化
Pub Date : 2024-05-21 DOI: 10.46481/jnsps.2024.1747
Olalekan Taofeek Wahab, Salaudeen Alaro Musa, Abdulazeez Jimoh, K. Dauda
Secure communication techniques are important due to the increase in the number of technology users across the world. Likewise, a more random encryption algorithm suitable to secure data from unauthorised users is highly expected. This paper proposes a two-parameter nonlinear chaos map that is sensitive to the trio seed (s0, alpha, lambda) and has better information encryption. We introduce the parameter alpha to linearise the conventional chaos system, which in turn brings a delay in the cryptosystems. The delay is a phenomenon that changes the chaotic features of a system. A small delay in the system leads to more aperiodicity and the unpredictability of the chaotic attractions. We normalise the new chaos map and use the Lipschitz and pseudo-contractive operators to obtain its irregularity region in Hilbert spaces. We also analyse the chaos map in terms of trajectory, Lyapunov exponent, complexity, and information entropy. Results obtained show that the new chaos map has a wide chaotic range and better statistical properties. It also maintains low complexity due to its linearity and produces more key spaces than most existing chaotic maps.
随着全球技术用户数量的增加,安全通信技术显得尤为重要。同样,人们也非常期待一种更随机的加密算法,以防止未经授权的用户窃取数据。本文提出了一种双参数非线性混沌图,它对三元种子(s0, alpha,lambda)敏感,并具有更好的信息加密效果。我们引入参数 alpha 来使传统混沌系统线性化,这反过来又会给密码系统带来延迟。延迟是一种改变系统混沌特征的现象。系统中的小延迟会导致更多的非周期性和混沌吸引力的不可预测性。我们对新的混沌图进行归一化处理,并使用 Lipschitz 和伪收缩算子来获得其在希尔伯特空间中的不规则区域。我们还从轨迹、Lyapunov 指数、复杂性和信息熵等方面分析了混沌图。结果表明,新的混沌图具有较宽的混沌范围和较好的统计特性。由于其线性,它还能保持较低的复杂度,并比大多数现有的混沌图产生更多的关键空间。
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引用次数: 0
A model for the control of transmission dynamics of human monkeypox disease in Sub-Saharan Africa 撒哈拉以南非洲人类猴痘传播动态控制模型
Pub Date : 2024-05-13 DOI: 10.46481/jnsps.2024.1800
Bolarinwa Bolaji, Abdullahi Ibrahim, Favour Ani, B. Omede, Godwin Acheneje
The Human Monkeypox virus has received significant research interest in recent times. While few researchers have studied the effects of vaccination on human-to-animal or animal-to-human Monkeypox transmission, others just studied the effects of treatment on human Monkeypox. In this article, we made the proposition of a deterministic vaccine model that deals with the dynamics of the effects of vaccination and treatment on human Monkeypox in sub-Saharan Africa. We investigated the effects of vaccination on the various epidemiological classes qualitatively. The findings from the analysis of the model are that the model possesses two equilibria, locally asymptotically stable disease-free equilibrium (DFE) when an epidemiological threshold - the effective reproductive number is less than unity, and locally asymptotically stable endemic equilibrium when the number is greater than unity. We then corroborated the theoretical findings with numerical simulations, which reveal that when the rate of vaccination is increased resulting in many newly born persons in the populace being vaccinated, the prevalence of the deadly scourge is significantly reduced, while newly born individuals that miss vaccination experience a drastic torment of the deadly disease that often occasion death. Further revelation from the simulations is that when greater efforts
近来,人类猴痘病毒引起了研究人员的极大兴趣。很少有研究人员研究接种疫苗对猴痘病毒在人与动物或动物与人之间传播的影响,其他研究人员只是研究治疗对猴痘病毒的影响。在本文中,我们提出了一个确定性疫苗模型,该模型涉及疫苗接种和治疗对撒哈拉以南非洲人类猴痘影响的动态变化。我们定性研究了疫苗接种对各种流行病类别的影响。对模型的分析结果表明,该模型有两个均衡点,即当流行病学临界值--有效繁殖数量小于一的时候,局部渐近稳定的无病均衡(DFE);当有效繁殖数量大于一的时候,局部渐近稳定的流行均衡(DFE)。我们随后通过数值模拟证实了这一理论发现,结果表明,当疫苗接种率提高,导致人口中许多新出生的人接种疫苗时,致命疾病的流行率会显著降低,而错过疫苗接种的新出生的人则会经历致命疾病的剧烈折磨,往往导致死亡。模拟实验的进一步启示是,如果加大力度
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引用次数: 0
Deep convolutional neural network based synthetic minority over sampling technique: a forfending model for fraudulent credit card transactions in financial institution 基于合成少数过度采样技术的深度卷积神经网络:金融机构欺诈性信用卡交易的防范模型
Pub Date : 2024-05-12 DOI: 10.46481/jnsps.2024.2037
L. G. Salaudeen, D. Gabi, M. Garba, H. Suru
Fraudulent credit card transactions are committed by unauthorized individuals and organizations employing methods such as phishing and social engineering fraud tactics. Researchers propose several Machine Learning (ML) techniques to deter the challenges of credit card fraud. However, the ML approaches are endorsed with some challenges, which makes the detection of credit card fraud extremely difficult. This study proposes a Deep Convolutional Neural Network (DCNN) with Synthetic Minority Oversampling Techniques (SMOTE) as an ideal solution. Kaggle datasets with 284,807 records and 31 features were exploited. Implementation was performed on the Google Colab cloud-based platform, embedding a Jupyter notebook setting with Graphical Processing Units (GPUs). Two experiments were conducted; the first was probed to determine suitable models among baseline models: Logistic Regression (LR), Random Forest (RF), Isolation Forest, and a single Deep Learning (DL) model of Multiple Layer Perceptron (MLP). The baseline models yielded an overfitting accuracy score, with recall, specificity, precision, and F1-score all presenting 1.00% respectively. This outcome is not sufficient in establishing findings on imbalanced data distribution as it's biased. This led to the construction of a new ML model incorporating Light Gradient Boosting Machine (LGBM), with Artificial Neural Network (ANN) and the proposed DCNN+SMOTE for the second experimental phase alongside baseline models. Experimental results via simulation show the proposed DCNN+SMOTE yielded awesome superclass performance across the board, displaying 1.00% results respectively. Its Error Rate (ER) and Null Error Rate (NER) are 0.00% distinctly. Meanwhile, the False Positive Rate (FPR) yields a 0.001% result, lesser and better than the baseline models.
未经授权的个人和组织采用网络钓鱼和社交工程欺诈策略等方法进行欺诈性信用卡交易。研究人员提出了多种机器学习(ML)技术,以应对信用卡欺诈的挑战。然而,机器学习方法也面临着一些挑战,使得信用卡欺诈的检测变得异常困难。本研究提出了一种采用合成少数群体过采样技术(SMOTE)的深度卷积神经网络(DCNN)作为理想的解决方案。本研究利用了包含 284 807 条记录和 31 个特征的 Kaggle 数据集。实施工作在谷歌 Colab 云平台上进行,嵌入了图形处理器(GPU)的 Jupyter 笔记本设置。共进行了两项实验:第一项实验是在基线模型中确定合适的模型:逻辑回归(LR)、随机森林(RF)、隔离森林以及多层感知器(MLP)的单一深度学习(DL)模型。基线模型的精确度得分过高,召回率、特异性、精确度和 F1 分数均分别为 1.00%。这一结果不足以确定不平衡数据分布的结论,因为它存在偏差。因此,在第二实验阶段,除了基线模型外,我们还构建了一个新的多线性模型,其中包括轻梯度提升机(LGBM)、人工神经网络(ANN)和拟议的 DCNN+SMOTE 模型。模拟实验结果表明,拟议的 DCNN+SMOTE 全面提高了超类性能,分别达到了 1.00%。其错误率(ER)和无效错误率(NER)分别为 0.00%。同时,误报率(FPR)为 0.001%,比基线模型低且更好。
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引用次数: 0
Modelling the co-infection of malaria and zika virus disease 模拟疟疾和寨卡病毒疾病的共同感染
Pub Date : 2024-05-12 DOI: 10.46481/jnsps.2024.1938
E. C. Duru, Godwin Christopher Ezike Mbah, M. Anyanwu, Nicholas Topman Nnamani
In this work, a new model for the co-infection of malaria and zika virus disease incorporating vaccination, treatment and vector control using sterile-insect technology (SIT) is formulated. The importance of this study is to highlight the possibility of the co-infection of humans with malaria and zika virus disease in any environment where both diseases co-circulate. Also, to suggest a new and comprehensive method for controlling the individual diseases and their co-infection. Through stability analysis, we showed that the disease-free equilibrium, (DFE) point of the co-infection model is locally asymptotically stable when the basic reproduction numbers, Rmz is less than one, and unstable otherwise. But, the DFE failed to be globally stable when Rmz < 1 which is an indication of existence of backward bifurcation in the model. This shows that bringing down the reproduction number, Rmz to less than one is not enough to eradicate the co-infection of the two diseases. Furthermore, it is shown that the two diseases have positive impact on the spread of each other, which could be attributed to misdiagnoses of one disease as the other. We also showed that effective treatment of infectious humans, increasing the rate of vaccination and employing sterile-insect technique to control the vectors significantly helped to control the individual diseases as well as the co-infection. From the results obtained in the study, it can be concluded that effective control of malaria and zika virus disease requires measures that will control their spread in both human and mosquito populations.
在这项研究中,我们利用昆虫不育技术(SIT)建立了一个疟疾和寨卡病毒疾病共同感染的新模型,其中包括疫苗接种、治疗和病媒控制。这项研究的重要性在于强调在疟疾和寨卡病毒疾病共同流行的任何环境中,人类都有可能同时感染这两种疾病。同时,提出一种新的、全面的方法来控制疟疾和寨卡病毒疾病。通过稳定性分析,我们发现当基本繁殖数 Rmz 小于 1 时,共同感染模型的无病平衡(DFE)点是局部渐近稳定的,反之则不稳定。但是,当 Rmz 小于 1 时,DFE 点无法达到总体稳定,这表明模型中存在向后分叉。这表明,将繁殖数 Rmz 降至小于 1 并不足以根除两种疾病的共同感染。此外,模型还显示这两种疾病会对彼此的传播产生积极影响,这可能是由于一种疾病被误诊为另一种疾病所致。我们还发现,有效治疗感染者、提高疫苗接种率和采用昆虫不育技术控制病媒,对控制单种疾病和合并感染有很大帮助。从研究结果中可以得出结论,要有效控制疟疾和寨卡病毒疾病,就必须采取措施控制它们在人类和蚊子群体中的传播。
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引用次数: 0
Enhancing cellulose fiber properties from chromolaena odorata and anana comosus through novel pulping chemical mixtures 通过新型制浆化学混合物提高臭椿和芒果的纤维素纤维性能
Pub Date : 2024-05-08 DOI: 10.46481/jnsps.2024.2033
O. Oluwasina, Mochamad Zakki Fahmi, O. Oluwasina
The production of cellulose with exceptional properties has led to the modification of chemical pulping methods and the development of newer chemical pulping methods. This study developed mixtures of sodium hydroxide, ethanol, and anthraquinone as new pulping chemicals to produce alpha-cellulose from pineapple leaves and Saim weed stems. The addition of anthraquinone was noticed to influence the pulp yield positively and the FTIR of all the cellulose has the characteristic cellulose bands. Calculated Total crystallinity index (TCI), (Lateral order index) LOI., and Hydrogen bond intensity (HBI) from the FTIR presented PLSHAEC (68.38 %) and SWSHQEC (67.74 %) having high crystallinity. From the XRD, the 2? by all the materials is attributed to cellulose I diffraction, and the crystallinity index aligned with FTIR determined crystallinity. The determined particle average diameter using ImageJ software showed that PLSHQEC 3.00 had the smallest value, followed by 5.17 for PLSHQC, 5.32 for SWSHQEC, and 6.03 for SWSHQEC. From the thermal analysis, the onset of the degradation of all the cellulose occurred at different temperatures: 247.10? (PLSHQC), 253.38? (PLSHQEC), 240.20? (SWSHQC) and 242.58? (SWSHQEC). The increase in yield, higher crystallinity index, and smaller fiber diameter of the cellulose demonstrated anthraquinone as a better additive to produce quality cellulose that would undergo easy chemical modification.
生产具有特殊性能的纤维素促使人们改变化学制浆方法,并开发出更新的化学制浆方法。本研究开发了氢氧化钠、乙醇和蒽醌的混合物作为新的制浆化学品,用于从菠萝叶和赛马草茎中生产α-纤维素。添加蒽醌对纸浆产量有积极影响,所有纤维素的傅立叶变换红外光谱都具有纤维素的特征带。根据傅立叶变换红外光谱计算的总结晶度指数(TCI)、侧序指数(LOI)和氢键强度(HBI)显示,PLSHAEC(68.38 %)和 SWSHQEC(67.74 %)具有较高的结晶度。从 XRD 中可以看出,所有材料中的 2.0% 都是纤维素 I 衍射的结果,结晶度指数与傅立叶变换红外光谱测定的结晶度一致。使用 ImageJ 软件测定的颗粒平均直径显示,PLSHQEC 3.00 的值最小,其次是 PLSHQC 5.17、SWSHQEC 5.32 和 SWSHQEC 6.03。从热分析结果来看,所有纤维素的降解都发生在不同的温度下:247.10?(PLSHQC)、253.38?(PLSHQEC)、240.20?(SWSHQC) 和 242.58? (SWSHQEC)。纤维素产量的增加、结晶度指数的提高和纤维直径的缩小表明,蒽醌是一种更好的添加剂,可用于生产易于进行化学改性的优质纤维素。
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引用次数: 0
Iterative method for the numerical solution of optimal control model for mosquito and insecticide 蚊虫和杀虫剂优化控制模型数值求解的迭代法
Pub Date : 2024-04-23 DOI: 10.46481/jnsps.2024.1965
S. Adamu, O. Aduroja, A. S. Onanaye, M. R. Odekunle, Pankaj Thakur
A linear multistep method is transformed into an iterative method based on Patade and Bhalekar's technique for the numerical solution of the optimal control problem modeled for mosquito and insecticide management using forward-backward sweep methods via Pontryagin's principle. Stability and convergence analysis of the iterative method are carried out, and it is found to be stable, convergent, and of order four. Results obtained by the method clearly show that the population of mosquitoes can be minimized to a large extent using the new iterative method while reducing the harmful effects of the insecticide, subsequently reducing the spread of malaria.
基于 Patade 和 Bhalekar 的技术,将线性多步法转化为迭代法,通过 Pontryagin 原理,用前向后扫方法对蚊虫和杀虫剂管理的最优控制问题模型进行数值求解。对迭代法进行了稳定性和收敛性分析,发现该方法是稳定、收敛和四阶的。该方法得到的结果清楚地表明,使用新的迭代方法可以在很大程度上减少蚊子数量,同时降低杀虫剂的有害影响,从而减少疟疾的传播。
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引用次数: 0
期刊
Journal of the Nigerian Society of Physical Sciences
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