Scientific African最新文献

Oil price shocks and human capital channels in Nigeria 尼日利亚的石油价格冲击和人力资本渠道

IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2024-09-26 DOI: 10.1016/j.sciaf.2024.e02410

Nigeria faces persistent challenges of high unemployment and poverty, worsened by its over-reliance on the oil sector. While many studies have investigated the relationship between oil price volatility and human capital development, few have examined how this relationship impacts both basic and advanced human capital channels in developing economies; this study addresses that gap by using a Structural Vector Auto Regression (SVAR) approach to investigate how oil price shocks influence human capital channels. Co-integration tests reveal significant long-term relationships among the variables. For the basic channel, oil price shocks are negatively associated with secondary school enrollment but positively linked to primary school enrollment. In the advanced channel, oil price has a positive effect on government expenditure on tertiary education but negatively affects tertiary institution enrollment. The impulse response function confirms that oil price fluctuations significantly affect both basic and advanced channels of human capital. The findings show the detrimental impact of oil price shocks on Nigeria's human capital development, which may negatively affect sustainable development. The study emphasises the urgent need for economic diversification to reduce the economy's vulnerability to oil shocks and promote long-term growth and human capital development.

尼日利亚面临着高失业率和贫困的长期挑战，而对石油部门的过度依赖又加剧了这一挑战。虽然许多研究都探讨了石油价格波动与人力资本发展之间的关系，但很少有研究探讨这种关系如何影响发展中经济体的基本人力资本渠道和高级人力资本渠道；本研究采用结构向量自动回归（SVAR）方法，探讨石油价格冲击如何影响人力资本渠道，从而弥补了这一空白。协整检验揭示了变量之间显著的长期关系。就基本渠道而言，石油价格冲击与中学入学率呈负相关，但与小学入学率呈正相关。在高级渠道中，石油价格对政府的高等教育支出有积极影响，但对高等教育机构的入学率有消极影响。脉冲响应函数证实，石油价格波动对人力资本的基本渠道和高级渠道都有显著影响。研究结果表明，石油价格冲击对尼日利亚的人力资本发展产生了不利影响，可能会对可持续发展产生负面影响。这项研究强调了经济多样化的迫切需要，以减少经济对石油冲击的脆弱性，促进长期增长和人力资本发展。

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引用次数: 0

Determinants of an extended metric of agricultural commercialization in Ghana 加纳农业商业化扩展指标的决定因素

IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2024-09-26 DOI: 10.1016/j.sciaf.2024.e02412

For smallholder farmers in sub-Saharan Africa, increasing productivity and agricultural commercialization are mooted as one of the pillars for agricultural development. However, the measurement of agricultural commercialization has been restricted to the household crop commercialization index (HCCI) that focuses on crops neglecting livestock. This study develops an extended metric of agricultural commercialization named household crop-livestock commercialization index (HCLCI), which combines crop and livestock commercialization with the argument that it is superior to the overly used HCCI. Fractional regression is used to estimate the determinants of the extended metric using secondary and primary data from Ghana. Results indicate that agricultural commercialization is low when examined with the HCCI and the HCLCI. However, the HCLCI (at 26.44 % and 29.76 %, respectively, for the GLSS7 and primary data) is much lower relative to the HCCI (at 35.20 % and 38.24, respectively) but higher than the livestock commercialization index (10.93 % and 8.21 %, respectively). The underlying simultaneous factors that boost agricultural commercialization are infrastructure variables (i.e., road, market, transport, and bank), institutional variable (i.e., agricultural cooperatives) and scale of production (i.e., land endowment and crop production diversity). These findings imply that Ghana needs to invest in infrastructure and farmer institutional development to boost agricultural commercialization.

对于撒哈拉以南非洲的小农来说，提高生产率和农业商业化被认为是农业发展的支柱之一。然而，对农业商业化的衡量一直局限于家庭作物商业化指数（HCCI），该指数只关注作物而忽视牲畜。本研究开发了一种扩展的农业商业化度量指标，名为家庭作物-牲畜商业化指数（HCLCI），它将作物和牲畜商业化结合在一起，并认为它优于过度使用的家庭作物商业化指数。利用加纳的二级和一级数据，采用分数回归法估算了扩展指标的决定因素。结果表明，如果使用 HCCI 和 HCLCI 进行检验，农业商业化程度较低。然而，相对于 HCCI（分别为 35.20 % 和 38.24 %），HCLCI（在 GLSS7 和原始数据中分别为 26.44 % 和 29.76 %）要低得多，但高于畜牧业商业化指数（分别为 10.93 % 和 8.21 %）。促进农业商业化的基本同步因素是基础设施变量（即道路、市场、运输和银行）、机构变量（即农业合作社）和生产规模（即土地禀赋和作物生产多样性）。这些研究结果表明，加纳需要投资于基础设施和农民机构发展，以促进农业商业化。

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引用次数: 0

Improvement of the hygrothermal efficiency numerically using CFD modeling in a full-scale ventilated room with Moroccan climates 利用 CFD 建模，在摩洛哥气候条件下的全尺寸通风房间中以数值方式提高湿热效率

IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2024-09-24 DOI: 10.1016/j.sciaf.2024.e02408

The objective of this work is to examine the humidity and the heat transfer distribution in a full scale aerated room in a steady and turbulent flow regime under winter conditions and for six different Moroccan climate types. To assimilate winter conditions, the floor is considered as a heating source and is stabilized at a high temperature (T_H)_, on the other hand, all other walls are subjected to convection heat transfer mode with an external temperature as a function of the climatic region and a surface transmission coefficient required by the Moroccan Agency of Energy Efficiency (AMEE). Four configurations are treated basing on the outlet and inlet openings position on the vertical walls for introducing and extracting air. Computational fluid dynamics was used to resolve the physical processes numerically. The developed physical model was validated on the basis of humidity and temperature distribution of the indoor environment. The primary objective of this study is to analyze the impact of ventilation on the distribution of humidity and temperature, and to seek the best configuration (size and position of entry/exit openings) that provides thermal comfort, as well as the impact of the thermal requirements imposed by the AMEE on residential thermal comfort in the studied Moroccan climatic zones. This work has allowed to find the optimal ventilation configuration during the winter season by analyzing several comfort indicators in the room.

这项工作的目的是研究在冬季条件下，摩洛哥六种不同气候类型的全尺寸充气房间在稳定和湍流状态下的湿度和传热分布情况。为了适应冬季条件，地板被视为热源并稳定在高温（TH）下，另一方面，所有其他墙壁都采用对流传热模式，外部温度是气候区域和摩洛哥能效局（AMEE）要求的表面传输系数的函数。根据垂直墙壁上用于引入和抽出空气的出口和入口位置，对四种配置进行了处理。计算流体动力学用于数值解析物理过程。根据室内环境的湿度和温度分布，对所开发的物理模型进行了验证。这项研究的主要目的是分析通风对湿度和温度分布的影响，并寻求提供热舒适度的最佳配置（入口/出口开口的大小和位置），以及 AMEE 对所研究的摩洛哥气候区住宅热舒适度提出的热要求的影响。这项工作通过分析室内的多项舒适度指标，找到了冬季的最佳通风配置。

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引用次数: 0

Molecular phylogenetic characterization of L-asparaginase-producing endophytic fungi inhabiting Prunus africana and Periploca linearifolia: Effect of incubation time and pH on enzyme production 栖息于非洲李和线叶紫苏的产L-天冬酰胺酶内生真菌的分子系统发育特征：培养时间和 pH 值对酶产量的影响

IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2024-09-24 DOI: 10.1016/j.sciaf.2024.e02368

The therapeutic use of L-asparaginase derived from bacterial sources has been constrained by various challenges, including toxicity and repression. This has prompted the exploration of alternative sources, particularly eukaryotic microorganisms like fungi, to enhance the safety and effectiveness of the L-asparaginase enzyme. This study aims to investigate the fungal endophytes inhabiting Periploca linearifolia and Prunus africana as a potential source of novel L-asparaginase. Additionally, the study seeks to examine the impact of incubation time and pH on L-asparaginase production. Standard surface sterilization techniques were used for isolation of endophytic fungi. Based on the research findings, 24 % of the fungal endophytes demonstrated a positive reaction for L-ASNase activity and were identified as Colletotrichum sydowii, Fusarium sporotrichioides, Fusarium solani, Cercospora canescens, Penicillium crustosum, Penicillium pancosmium, Phoma sp, Penicillium ubiquetum, septoria sp and Penicillium commune. A significant variation in the production of L-asparaginase based on the time of incubation and pH was observed. Most endophytic fungal isolates exhibit optimal enzyme activity on the 6th day of incubation. However, both Septoria sp and Colletotrichum sydowii recorded the highest L-asparaginase activity on the 9th day of incubation. Fusarium solani demonstrated peak activity of 12.4 ± 1.12 UI/mL on the 12th day of incubation. The optimal pH for L-asparaginase production by fungal endophytes was found to be between 5 and 6. The fungal endophytes isolated from medicinal plants have the potential to serve as sources of novel L-asparaginase. Furthermore, it is evident that fungal endophytes display considerable variation in L-asparaginase production, influenced by the duration of incubation and pH conditions.

来自细菌的 L-天冬酰胺酶的治疗用途一直受到各种挑战的限制，包括毒性和抑制作用。这促使人们探索替代来源，特别是真核微生物（如真菌），以提高 L-天冬酰胺酶的安全性和有效性。本研究旨在调查栖息在线叶紫苏（Periploca linearifolia）和非洲李（Prunus africana）中的真菌内生菌，将其作为新型 L-天冬酰胺酶的潜在来源。此外，该研究还试图考察培养时间和 pH 值对 L-天冬酰胺酶生产的影响。分离内生真菌时使用了标准的表面灭菌技术。根据研究结果，24% 的真菌内生菌对 L-ASNase 活性呈阳性反应，并被鉴定为 Colletotrichum sydowii、Fusarium sporotrichioides、Fusarium solani、Cercospora canescens、Penicillium crustosum、Penicillium pancosmium、Phoma sp、Penicillium ubiquetum、septoria sp 和 Penicillium commune。根据培养时间和 pH 值的不同，L-天冬酰胺酶的产量也有很大差异。大多数内生真菌分离物在培养的第 6 天表现出最佳酶活性。然而，Septoria sp 和 Colletotrichum sydowii 在培养第 9 天时的 L-天冬酰胺酶活性最高。Fusarium solani 在培养的第 12 天表现出 12.4 ± 1.12 UI/mL 的峰值活性。研究发现，真菌内生菌产生 L-天冬酰胺酶的最佳 pH 值为 5 至 6。从药用植物中分离出的真菌内生菌有可能成为新型 L-天冬酰胺酶的来源。此外，真菌内生菌的 L-天冬酰胺酶产量显然受培养时间和 pH 值条件的影响而有很大差异。

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引用次数: 0

Energy recovery from solid waste valorisation: Environmental and economic potential for developing countries 从固体废物价值中回收能源：发展中国家的环境和经济潜力

IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2024-09-21 DOI: 10.1016/j.sciaf.2024.e02402

Solid waste management in developing countries faces challenges such as rising populations, inadequate planning, poor collection and storage, improper disposal, insufficient technology, and a lack of basic waste management knowledge. Predominantly, waste is disposed of in open dumps, on vacant land, or burned by residents, leading to significant pollution and health risks. Developing countries should adopt solid waste management techniques used by developed nations, with waste-to-energy (WTE) technology being particularly suitable. WTE reduces waste volume and mass, environmental impact, health risks, and reliance on fossil fuels. Fossil fuel exploitation poses severe environmental risks, highlighting the need for secure, sustainable, and renewable energy sources. Biochemical technologies, ideal for high-moisture waste prevalent in developing countries, offer a promising solution. This study examines the potential of WTE valorization in developing countries, evaluating the pros and cons of various WTE conversion technologies and their feasibility. The findings indicate that WTE technologies are underutilized in developing countries. The review suggests that WTE can provide renewable energy, meet energy demands, and improve solid waste management, thereby addressing environmental pollution in developing countries.

发展中国家的固体废物管理面临着人口增加、规划不足、收集和储存不善、处置不当、技术不足以及缺乏基本废物管理知识等挑战。废物主要被丢弃在露天垃圾场、空地上或被居民焚烧，导致严重污染和健康风险。发展中国家应采用发达国家使用的固体废物管理技术，其中废物变能源（WTE）技术尤为适用。废物变能源技术可以减少废物的数量和质量、环境影响、健康风险以及对化石燃料的依赖。化石燃料的开采带来了严重的环境风险，突出了对安全、可持续和可再生能源的需求。生化技术非常适合发展中国家普遍存在的高水分废物，是一种前景广阔的解决方案。本研究探讨了发展中国家废物变废为宝的潜力，评估了各种废物变废为宝转化技术的利弊及其可行性。研究结果表明，湿热发电技术在发展中国家利用不足。研究表明，废物转化技术可以提供可再生能源，满足能源需求，改善固体废物管理，从而解决发展中国家的环境污染问题。

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引用次数: 0

On bank stock return spillovers in South Africa: Implications for portfolio hedging 南非银行股票回报溢出效应：对投资组合对冲的影响

IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2024-09-21 DOI: 10.1016/j.sciaf.2024.e02406

The purpose of this study is to investigate the return spillovers among the five systemically important banks in South Africa. The study employs a time-varying parameter vector autoregression (TVP-VAR) framework utilising daily data between 2000 and 2024. A minimum return connectedness portfolio is constructed from the spillover indexes and compared with traditional portfolio optimisation methods in terms of risk reduction and reward-to-risk ratios. The research findings reveal that Capitec, the smallest bank in terms of assets, has weaker return connectedness with other banks while ABSA, FirstRand, Nedbank and Standard Bank are moderately connected. Moreover, the two largest banks in terms of assets, Standard and FirstRand, are more connected than any other pairwise connection in the network. During significant events such as national elections, the global financial crisis and the COVID-19 pandemic, system-wide connectedness increases.

本研究旨在调查南非五家具有系统重要性的银行之间的回报溢出效应。研究采用了时变参数向量自回归（TVP-VAR）框架，利用了 2000 年至 2024 年间的每日数据。根据溢出指数构建了最低回报关联性投资组合，并在风险降低和回报风险比方面与传统投资组合优化方法进行了比较。研究结果显示，资产规模最小的 Capitec 银行与其他银行的回报关联度较弱，而 ABSA、FirstRand、Nedbank 和标准银行的关联度适中。此外，资产规模最大的两家银行--标准银行和 FirstRand 银行--在网络中的关联度高于其他任何成对关联。在全国大选、全球金融危机和 COVID-19 大流行等重大事件期间，整个系统的关联性会增加。

引用次数: 0

Spatiotemporal climate variability and food security implications in the Central Ethiopia Region 埃塞俄比亚中部地区时空气候变异性及其对粮食安全的影响

IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2024-09-21 DOI: 10.1016/j.sciaf.2024.e02390

Studies focusing on the spatiotemporal distribution of climatic parameters and meteorological drought are of paramount significance for countries like Ethiopia, where climate change and variability cause major losses to rain-dependent agriculture. In this study, the National Meteorology Institute of Ethiopia provided an Enhanced National Climate Services (ENACTS) dataset at a spatial resolution of approximately 4 km by 4 km over 38 years (1981–2018) was used to study climate trends, spatiotemporal variability, and meteorological drought in the Central Ethiopia Region. Coefficient of variation (CV), Standardized Rainfall Anomaly (SRA), Standardized Precipitation Index (SPI), Mann-Kendall trend test, and Sen's slope were used for the analysis. The findings suggest that Belg rainfall (also known as "small-rain") varied greatly in space and time over the study area, with area-averaged CV of 29 % and pixel-level CVs ranging from 63 to 93 %. The average precipitation during Belg experienced a 15 % decrease from 2000 to 2019 compared to the preceding two decades, from 1981 to 1999. The maximum temperature has increased significantly during the Annual, Belg, and Bega seasons. The SPI and SRA showed that there have been multiple drought episodes with rising negative rainfall anomalies, with a drought occurring every 2.9 years during the Kiremt (also called "big rain", spanning from June to September) and Belg seasons. The growing negative rainfall anomaly, high CV, and highly significant increase in mean maximum temperature during the Belg season is concerning for food security and poverty eradication. The notable rise in rainfall during the June (sowing period) and November (harvesting period) also hurts crop production during the main cropping season. Thus, developing appropriate adaptation strategies and policies oriented toward climate-resilient agriculture is crucial to meet the global sustainable development goals (SDGs) and Africa Union's Agenda 2063.

在埃塞俄比亚等国，气候变化和多变性给依赖降雨的农业造成了重大损失，因此，对气候参数的时空分布和气象干旱进行重点研究意义重大。本研究利用埃塞俄比亚国家气象研究所提供的增强型国家气候服务（ENACTS）数据集（空间分辨率约为 4 千米乘 4 千米，时间跨度为 38 年（1981-2018 年））研究埃塞俄比亚中部地区的气候趋势、时空变异性和气象干旱。分析中使用了变异系数（CV）、标准化降雨异常（SRA）、标准化降水指数（SPI）、Mann-Kendall 趋势检验和森氏斜率。研究结果表明，贝尔格降雨量（又称 "小雨"）在研究区域内的时空变化很大，区域平均 CV 为 29%，像素级 CV 为 63% 至 93%。与前二十年（1981-1999 年）相比，2000-2019 年贝尔格平均降水量减少了 15%。全年、Belg 和 Bega 季节的最高气温明显升高。SPI 和 SRA 显示，在 Kiremt（又称 "大雨"，时间跨度为 6 月至 9 月）和 Belg 季节，每隔 2.9 年就会发生一次干旱。贝尔格季节的降雨负异常值不断增加，CV 值较高，平均最高气温显著升高，这对粮食安全和消除贫困而言令人担忧。6 月（播种期）和 11 月（收获期）降雨量的显著增加也损害了主要耕种季节的作物产量。因此，为实现全球可持续发展目标（SDGs）和非洲联盟《2063 年议程》，制定适当的适应战略和政策，发展具有气候抗御能力的农业至关重要。

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引用次数: 0

The novel Vogel's approximation method integrated with a random forest algorithm in the vibration analysis of a two-directional functionally graded taper porous beam: Assessment 新型 Vogel 近似法与随机森林算法在双向功能分级锥形多孔梁振动分析中的集成：评估

IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2024-09-20 DOI: 10.1016/j.sciaf.2024.e02397

A functionally graded material is a class of composite materials characterized by gradual variations in composition and microstructure, which further induces the respective changes in the material properties. This study focuses on evaluating the vibration behavior of two directional functionally graded taper porous beams (FGTPB). This approach adopts a rectangular cross-section in order to deal with the challenges related to fluctuating material characteristics and geometric tapering in both thickness and width dimensions. The research employs a novel approach that merges Vogel's approximation technique with the Random Forest algorithm, an approach that has not been used in analyzing structural vibrations, establish boundary conditions and solve equations of motion. Comparative results of the suggested beam theory with the existing literature on FGTPB materials such as alumina and SUS304 at various taper, porosity, gradient and width ratios verified it. The material gradation and porosity developed a uniform pattern in the first three modes of fundamental frequencies. Higher gradient indices increased the rigidity and natural frequencies of the beams whereas the porosity index decreased the rigidity, resulting in lower natural frequencies. By combining Vogel's approximation method with machine learning techniques, the study improved vibration behavior analysis in FGTPB. The disciplines of materials and structural engineering are significantly impacted by this.

功能分级材料是一类复合材料，其特点是成分和微观结构逐渐变化，从而进一步引起材料性能的相应变化。本研究的重点是评估双向功能分级锥形多孔梁（FGTPB）的振动行为。该方法采用矩形截面，以应对与材料特性波动以及厚度和宽度尺寸的几何锥度相关的挑战。研究采用了一种新颖的方法，将 Vogel 近似技术与随机森林算法（一种尚未用于分析结构振动、建立边界条件和求解运动方程的方法）相结合。建议的梁理论与现有文献中的 FGTPB 材料（如氧化铝和 SUS304）在不同锥度、孔隙率、梯度和宽度比下的比较结果得到了验证。材料的梯度和孔隙率在前三个基频模式中形成了统一的模式。梯度指数越高，梁的刚度和固有频率就越高，而孔隙度指数则会降低刚度，从而降低固有频率。通过将 Vogel 近似方法与机器学习技术相结合，该研究改进了 FGTPB 的振动行为分析。材料和结构工程学科将因此受到重大影响。

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引用次数: 0

Assessing soil erosion risk through geospatial analysis and magnetic susceptibility: A study in the Oued Ghiss dam watershed, Central Rif, Morocco 通过地理空间分析和磁感应强度评估土壤侵蚀风险：摩洛哥中部里夫省 Oued Ghiss 大坝流域研究

IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2024-09-19 DOI: 10.1016/j.sciaf.2024.e02401

In northern Morocco, water erosion presents a critical risk for soil degradation and dam sedimentation, attributable to extreme climatic conditions, variegated topography, lithological vulnerabilities, and anthropogenic pressures. This study quantitatively and spatially evaluates soil erosion susceptibility within the catchment area of the Oued Ghiss dam in Central Rif, Morocco. Utilizing the Revised Universal Soil Loss Equation (RUSLE) integrated with Geographic Information Systems (GIS) and calibrated through magnetic susceptibility metrics, the study provides a detailed analysis of erosion factors. The model was applied using GIS to spatially analyze data on rainfall, soil type, topography, land cover, and management practices, with magnetic susceptibility measurements used to calibrate the model by identifying stable and erosion-prone areas. The resultant soil loss map reveals a mean erosion rate of 24 t/ha/year. Specifically, 37.28 % of the catchment area exhibits an erosion rate under 5 t/ha/year, 40.16 % between 5 and 10 t/ha/year, 22.77 % between 10 and 20 t/ha/year, and 0.86 % surpasses 20 t/ha/year. Magnetic susceptibility measurements across various soil profiles indicated that stable soils showed increased susceptibility towards the surface, while eroded soils displayed decreased susceptibility, with significant correlations found between magnetic susceptibility variations and the final risk map. This innovative calibration of the RUSLE model through magnetic susceptibility improves erosion vulnerability assessments and results in a more detailed soil loss map. The findings provide critical information for policymakers to develop targeted management plans for erosion-prone areas, particularly benefiting the Ghiss dam watershed, where these insights will aid in preventing dam siltation and enhancing water resource management. This confirms magnetic susceptibility's reliability in assessing soil erosion vulnerability and improving numerical models.

在摩洛哥北部，由于极端的气候条件、多变的地形、岩性的脆弱性以及人为压力，水土流失对土壤退化和大坝沉积构成了严重威胁。本研究对摩洛哥里夫中部 Oued Ghiss 大坝集水区的土壤侵蚀易发性进行了定量和空间评估。该研究利用与地理信息系统 (GIS) 相结合的修订通用土壤流失方程 (RUSLE)，并通过磁感应强度指标进行校准，对侵蚀因素进行了详细分析。该模型利用地理信息系统对降雨量、土壤类型、地形、土地覆盖和管理方法等数据进行空间分析，并通过磁感应强度测量确定稳定区和易受侵蚀区，对模型进行校准。由此绘制的土壤流失图显示，平均侵蚀率为 24 吨/公顷/年。具体而言，37.28%的流域面积的侵蚀率低于 5 吨/公顷/年，40.16%介于 5 至 10 吨/公顷/年之间，22.77%介于 10 至 20 吨/公顷/年之间，0.86%超过 20 吨/公顷/年。不同土壤剖面的磁感应强度测量结果表明，稳定的土壤向地表方向的磁感应强度增加，而侵蚀的土壤磁感应强度降低，磁感应强度变化与最终风险图之间存在显著的相关性。这种通过磁感应强度对 RUSLE 模型进行校准的创新方法改进了侵蚀脆弱性评估，并生成了更详细的土壤流失图。这些发现为政策制定者提供了重要信息，帮助他们为水土流失易发地区制定有针对性的管理计划，特别是吉斯大坝流域，这些发现将有助于防止大坝淤积和加强水资源管理。这证实了磁感应强度在评估土壤侵蚀脆弱性和改进数值模型方面的可靠性。

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引用次数: 0

Stock price prediction using combined GARCH-AI models 使用 GARCH-AI 组合模型预测股价

IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2024-09-19 DOI: 10.1016/j.sciaf.2024.e02374

The non-linear and non-stationary nature of financial time series data poses significant challenges for standalone statistical and neural network methods. While predictive modeling in finance often focuses on volatility, there is a notable lack of research on predicting actual stock prices, particularly in the African market. This study addresses this gap by utilizing Airtel stock data from Yahoo Finance, spanning June 28, 2019, to May 8, 2024. The research employs the GARCH model to extract statistical properties, which are then combined with historical prices and fed into LSTM, GRU, and Transformer models leading to GARCH-LSTM, GARCH-GRU, GARCH-Transfomer hybrid models. These hybrid models are benchmarked against standalone LSTM, GRU and Transfomer models using RMSE, MAE, MAPE, and R-squared metrics. Results indicate that hybrid models, especially GARCH-LSTM, significantly outperform standalone models. This integration of GARCH with advanced AI models offers a more robust framework for stock price prediction, enhancing accuracy and reliability in forecasting future prices.

金融时间序列数据的非线性和非平稳性给独立的统计和神经网络方法带来了巨大挑战。虽然金融领域的预测建模通常侧重于波动性，但对实际股票价格的预测研究却明显不足，尤其是在非洲市场。本研究利用雅虎财经提供的 Airtel 股票数据（时间跨度为 2019 年 6 月 28 日至 2024 年 5 月 8 日）填补了这一空白。研究采用 GARCH 模型提取统计属性，然后将其与历史价格相结合，并输入 LSTM、GRU 和 Transformer 模型，最终形成 GARCH-LSTM、GARCH-GRU、GARCH-Transfomer 混合模型。使用 RMSE、MAE、MAPE 和 R 平方指标对这些混合模型与独立的 LSTM、GRU 和 Transfomer 模型进行了基准测试。结果表明，混合模型，尤其是 GARCH-LSTM 明显优于独立模型。GARCH 与先进人工智能模型的整合为股票价格预测提供了一个更稳健的框架，提高了预测未来价格的准确性和可靠性。

引用次数: 0