Models, Theoretical

模型, 理论
  • 文章类型: Journal Article
    世界各地城市的加速城市扩张对城市规划和土地资源管理提出了重大挑战。在这种情况下,这是至关重要的有一个详细的3D表示建筑物丰富的准确的字母数字信息。该提案的一个独特方面是其特别关注与建筑物相对应的空间单元。为了提出用于建筑物的3D表示的领域模型,考虑了厄瓜多尔国家标准和国际标准(ISO19152:2012LADM)。该提案包括详细的属性规范,既适用于建筑物的一般子类,也适用于其基础设施。领域模型提案的应用在位于Riobamba州的研究区中至关重要,由于该地区建筑物的特点。为此,在pgAdmin4中创建了一个带有官方信息的地理数据库,考虑到拟议模型的结构,并将其与地理空间数据链接,以便在开源地理信息系统中对建筑物进行适当的管理和3D表示。此应用程序可改善研究区域的地籍管理,并具有更广泛的意义。该模型旨在作为其他在地籍管理和建筑物3D表示方面面临类似挑战的国家的基准。促进城市高效发展,为全球可持续发展做出贡献。
    The accelerated urban sprawl of cities around the world presents major challenges for urban planning and land resource management. In this context, it is crucial to have a detailed 3D representation of buildings enriched with accurate alphanumeric information. A distinctive aspect of this proposal is its specific focus on the spatial unit corresponding to buildings. In order to propose a domain model for the 3D representation of buildings, the national standard of Ecuador and the international standard (ISO 19152:2012 LADM) were considered. The proposal includes a detailed specification of attributes, both for the general subclass of buildings and for their infrastructure. The application of the domain model proposal was crucial in a study area located in the Riobamba canton, due to the characteristics of the buildings in that area. For this purpose, a geodatabase was created in pgAdmin4 with official information, taking into account the structure of the proposed model and linking it with geospatial data for an adequate management and 3D representation of the buildings in an open-source Geographic Information System. This application improves cadastral management in the study region and has wider implications. This model is intended to serve as a benchmark for other countries facing similar challenges in cadastral management and 3D representation of buildings, promote efficient urban development and contribute to global sustainable development.
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  • 文章类型: Journal Article
    使用反事实情景的基于自然的解决方案在很大程度上取决于用于确定照常业务(BAU)案例的方法,即,“基线”。“减少毁林和森林退化所致排放量(REDD+)项目传统上使用“参考区域”来设定基线,作为估算处理(项目)区域中BAU毁林和排放量的控制。虽然REDD+市场正在从基于项目的方式转向嵌套方式,因为各国加大了努力,以实现国家自主贡献(NDC)对《巴黎协定》全球气候目标,分配国家基线的方法尚未正式确定和测试,尽管迫切需要扩大市场规模。我们提出了一种新的方法来绘制森林砍伐风险图,并将国家森林参考排放水平(FREL)分配给项目:评估风险的基线分配(BAAR)。这种方法使用动态向量提供了未来森林砍伐的空间预测器,以及在项目级别将FREL分配到有区别的风险区域的方法。这里,我们在刚果民主共和国(DRC)使用34个REDD+项目介绍BAAR。我们证明了基于风险的FREL分配对平衡目标适应性和科学严谨性的重要性。我们展示了政府如何利用BAAR将自愿碳市场融资集中在森林砍伐风险最高的地区,同时保持与国家自主贡献(NDC)目标的一致性。
    Nature-based solutions that use a counterfactual scenario depend heavily on the methodology used to determine the business as usual (BAU) case, i.e., the \"baseline.\" Reducing emissions from deforestation and forest degradation (REDD+) projects traditionally set baselines using a \"reference area\" as a control for estimating BAU deforestation and emissions in the treatment (project) area. While the REDD+ market is shifting from project-based to nested approaches as countries increase their efforts to meet nationally determined contributions (NDCs) to the Paris agreement\'s global climate target, methodologies for allocating national baselines are not yet formalized and tested, despite an urgent need to scale the market. We present a novel method for mapping deforestation risk and allocating national forest reference emission levels (FREL) to projects: baseline allocation for assessed risk (BAAR). This approach provides a spatial predictor of future deforestation using a dynamic vector, and a method for allocating a FREL to differentiated risk areas at the project level. Here, we present BAAR using 34 REDD+ projects in the Democratic Republic of the Congo (DRC). We demonstrate the importance of risk-based FREL allocations to balance fitness for purpose and scientific rigor. We show how BAAR can be used by governments to focus voluntary carbon market finance in areas at highest risk of imminent deforestation, while maintaining alignment with nationally determined contribution (NDC) goals.
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  • 文章类型: Journal Article
    目的:使用创新扩散理论模型描述HIV/AIDS患者(PLWHA)如何做出决策。决策发生在个人决策者参与指导选择采用或拒绝特定创新的活动时。
    方法:这是一项使用调查方法的描述性分析研究。使用决策问卷进行数据收集。这项研究的对象是居住在Turen的HIV/AIDS患者(PLWHA),印度尼西亚。2023年1月,使用目的抽样技术获得的研究对象数量为36名受访者。
    结果:研究设计使用具有横截面方法的相关方法和Spearman相关系数统计检验。研究结果显示(2尾)为0.934(p>0.05)。相关系数结果为负。其中相关性产生的方向表现出非常弱的关系,值为0.014,变量之间的分析结果不相同。这是因为说服阶段没有在分析中进行测试。研究表明,有8名(22.2%)患者拒绝了PLWHA使用西方公积金协会Turen基金会的创新理论模型扩散的决策,Turen,印度尼西亚,28例(77.7%)患者接受。可以得出结论,艾滋病毒/艾滋病患者在ADISTurenPeduliWarga基金会做出的大多数决定都被接受。
    结论:艾滋病毒/艾滋病患者的知识处于良好水平,他们的决策大多被接受,并且在使用聊天机器人创新时,知识和决策之间存在有意义的关系。该研究的建议是,这种聊天机器人创新可以成为进一步研究的来源,并有助于为PLWHA患者的日常生活提供教育。
    OBJECTIVE: To describe how people living with HIV/AIDS (PLWHA) make decisions using the diffusion of innovation theory model. Decisions occur when individual decision makers engage in activities that guide choices to adopt or reject a particular innovation.
    METHODS: This is a descriptive analysis research using a survey method. Data collection was carried out using a decision making questionnaire. The subjects in this research were HIV/AIDS sufferers (PLWHA) who lived in Turen, Indonesia. The number of research subjects was 36 respondents obtained using the purposive sampling technique on January 2023.
    RESULTS: The research design used the correlation method with a cross sectional approach and the Spearman correlation coefficient statistical test. The research results show significance (2-tailed) of 0.934 (p>0.05). The correlation coefficient results are negative. Where the direction of the correlation produces showed a very weak relationship with a value of 0.014 and the results of the analysis between variables are not the same. This is because the persuasion stage was not tested in the analysis. Research shows that 8 (22.2%) patients rejected the decision making of PLWHA using the diffusion of innovation theory model at the Western Provident Association Turen Foundation, Turen, Indonesia, while 28 (77.7%) patients accepted it. It can be concluded that the majority of decisions made by HIV/AIDS patients at the ADIS Turen Peduli Warga Foundation are accepted.
    CONCLUSIONS: Knowledge of HIV/AIDS sufferers is at a good level, their decision making is mostly accepted and there is a meaningful relationship between knowledge and decision making in using a chatbot innovation. The suggestion from the research is that this chatbot innovation can be a source of further research and help provide education for PLWHA patients in everyday life.
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  • 文章类型: Journal Article
    改进的Benjamin-Bona-Mahony(mBBM)模型用于视错觉领域,以描述视觉错觉期间长波在非线性色散介质中的传播(Khater2021)。本文通过利用有理[公式:参见正文]-展开技术来研究mBBM方程,以得出新的解析波解。我们获得的解析解包括双曲,三角,和合理的功能。在特定情况下,这些精确解决方案中的一些与先前发布的结果密切相关,确认我们其他解决方案的有效性。为了提供对不同波传播特性的见解,我们使用2D对这些解决方案进行了深入分析,3D,和密度图。我们还研究了各种参数对模型获得的波解特性的影响。此外,我们采用线性稳定性技术对所考虑的模型进行稳定性分析。此外,我们通过应用相平面理论探讨了相关动力系统的稳定性。这项研究还证明了有理[公式:参见正文]-展开方法在从非线性偏微分方程中分析和提取孤子解方面的功效和能力。
    The modified Benjamin-Bona-Mahony (mBBM) model is utilized in the optical illusion field to describe the propagation of long waves in a nonlinear dispersive medium during a visual illusion (Khater 2021). This article investigates the mBBM equation through the utilization of the rational [Formula: see text]-expansion technique to derive new analytical wave solutions. The analytical solutions we have obtained comprise hyperbolic, trigonometric, and rational functions. Some of these exact solutions closely align with previously published results in specific cases, affirming the validity of our other solutions. To provide insights into diverse wave propagation characteristics, we have conducted an in-depth analysis of these solutions using 2D, 3D, and density plots. We also investigated the effects of various parameters on the characteristics of the obtained wave solutions of the model. Moreover, we employed the techniques of linear stability to perform stability analysis of the considered model. Additionally, we have explored the stability of the associated dynamical system through the application of phase plane theory. This study also demonstrates the efficacy and capabilities of the rational [Formula: see text]-expansion approach in analyzing and extracting soliton solutions from nonlinear partial differential equations.
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  • 文章类型: Journal Article
    渔业管理的预防方法要求评估不确定性对实现管理目标的风险的影响。然而,主要数量,例如产卵种群生物量(SSB)和鱼类死亡率(F),管理度量中使用的度量不能直接观察。这就需要使用模型来提供指导,有三种范例:最佳评估,模型合奏,和管理策略评估(MSE)。验证用于提供建议的模型很重要。在这项研究中,我们演示了如何使用诊断工具箱验证股票评估模型,特别关注预测技能。预测技能测量预测值的精度,这是模型未知的,相对于它的观察值。通过根据观测数据评估模型预测的准确性,预测技能建立了一个接受或拒绝模型假设的客观框架,以及为集合中的模型分配权重。我们的分析揭示了传统股票评估方法的局限性。通过不确定性的量化和多个模型的集成,考虑到影响鱼类种群动态的因素的复杂相互作用,我们的目标是提高管理建议的可靠性。
    The Precautionary Approach to Fisheries Management requires an assessment of the impact of uncertainty on the risk of achieving management objectives. However, the main quantities, such as spawning stock biomass (SSB) and fish mortality (F), used in management metrics cannot be directly observed. This requires the use of models to provide guidance, for which there are three paradigms: the best assessment, model ensemble, and Management Strategy Evaluation (MSE). It is important to validate the models used to provide advice. In this study, we demonstrate how stock assessment models can be validated using a diagnostic toolbox, with a specific focus on prediction skill. Prediction skill measures the precision of a predicted value, which is unknown to the model, in relation to its observed value. By evaluating the accuracy of model predictions against observed data, prediction skill establishes an objective framework for accepting or rejecting model hypotheses, as well as for assigning weights to models within an ensemble. Our analysis uncovers the limitations of traditional stock assessment methods. Through the quantification of uncertainties and the integration of multiple models, our objective is to improve the reliability of management advice considering the complex interplay of factors that influence the dynamics of fish stocks.
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  • 文章类型: Journal Article
    在本文中,我们提出了COVID-19的数学模型,其中病毒的多个变种处于最优控制之下.数学建模已被用来更深入地了解COVID-19的传播,并实施了各种预防和控制策略来减轻其传播。我们的模型是基于SEIR的多菌株COVID-19模型,具有7个隔室。我们还考虑了导致COVID-19免疫终止的循环结构。根据解的积极性和有界性以及平衡点的存在性建立了模型,解的局部稳定性。由于加纳的COVID-19数据与模型拟合,原始病毒和Delta变体的基本繁殖数估计为1.9396,Omicron变体的基本繁殖数估计为3.4905,是其1.8倍。我们观察到,具有相同初始传播率的两种菌株的潜伏期和恢复期即使有很小的差异,也会导致受感染个体数量的巨大差异。在COVID-19的情况下,由Omicron变体引起的感染比原始病毒引起的感染多1.5至10倍。在最优控制策略方面,我们制定了三种关注社会距离的控制策略,疫苗接种,和测试治疗。我们使用Pontryagin的最大原理为上述多应变模型的三种策略开发了最优控制模型。通过数值模拟,我们分析了每种应变的三种最优控制策略,并考虑了两种控制策略的组合。作为模拟的结果,所有控制策略都能有效减少疾病传播,特别是,疫苗接种策略比其他两种控制策略更有效。此外,与实施一种策略相比,两种策略的组合还使感染人数减少了1/10,即使实施轻度水平。最后,我们表明,如果测试-治疗策略没有得到正确实施,无症状和身份不明的感染人数可能会激增。这些结果有助于指导政府干预水平和预防策略的制定。
    In this paper, we suggest a mathematical model of COVID-19 with multiple variants of the virus under optimal control. Mathematical modeling has been used to gain deeper insights into the transmission of COVID-19, and various prevention and control strategies have been implemented to mitigate its spread. Our model is a SEIR-based model for multi-strains of COVID-19 with 7 compartments. We also consider the circulatory structure to account for the termination of immunity for COVID-19. The model is established in terms of the positivity and boundedness of the solution and the existence of equilibrium points, and the local stability of the solution. As a result of fitting data of COVID-19 in Ghana to the model, the basic reproduction number of the original virus and Delta variant was estimated to be 1.9396, and the basic reproduction number of the Omicron variant was estimated to be 3.4905, which is 1.8 times larger than that. We observe that even small differences in the incubation and recovery periods of two strains with the same initial transmission rate resulted in large differences in the number of infected individuals. In the case of COVID-19, infections caused by the Omicron variant occur 1.5 to 10 times more than those caused by the original virus. In terms of the optimal control strategy, we formulate three control strategies focusing on social distancing, vaccination, and testing-treatment. We have developed an optimal control model for the three strategies outlined above for the multi-strain model using the Pontryagin\'s Maximum Principle. Through numerical simulations, we analyze three optimal control strategies for each strain and also consider combinations of the two control strategies. As a result of the simulation, all control strategies are effective in reducing disease spread, in particular, vaccination strategies are more effective than the other two control strategies. In addition the combination of the two strategies also reduces the number of infected individuals by 1/10 compared to implementing one strategy, even when mild levels are implemented. Finally, we show that if the testing-treatment strategy is not properly implemented, the number of asymptomatic and unidentified infections may surge. These results could help guide the level of government intervention and prevention strategy formulation.
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  • 文章类型: Journal Article
    在这项研究中,我们采用有效的李群分析技术来推导(31)扩展的Kadomtsev-Petviashvili(3D-EKP)方程的解析解。该方法的系统应用可以识别与方程相关的李点对称性,导致推导与方程相关的一维子代数的最优系统。该最佳系统用于获得多个不变解。随后将李群方法应用于从给定方程导出的简化控制方程。我们用Mathematica模拟补充了我们的发现,说明了一些获得的解决方案。此外,使用直接方法来调查当地的守恒定律。重要的是,我们的研究解决了使用群论方法探索3D-EXP方程的差距,使我们的发现在这种情况下新颖。
    In this research, we employ the potent technique of Lie group analysis to derive analytical solutions for the (3+1)-extended Kadomtsev-Petviashvili (3D-EKP) equation. The systematic application of this method enables the identification of Lie point symmetries associated with the equation, leading to the derivation of an optimal system of one-dimensional subalgebras relevant to the equation. This optimal system is utilized to obtain several invariant solutions. The Lie group method is subsequently applied to the reduced governing equations derived from the given equation. We complement our findings with Mathematica simulations illustrating some of the obtained solutions. Furthermore, a direct approach is used to investigate local conservation laws. Importantly, our study addresses a gap in the exploration of the 3D-EXP equation using group theoretic methods, making our findings novel in this context.
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  • 文章类型: Journal Article
    人为磷(P)的过量排放给水生生态系统带来了持续的压力。通过将P排放联系起来,可以将该压力量化为淡水富营养化潜力(FEP)。环境隔室中的P命运,以及由于淡水中P浓度增加而可能消失的物种部分。然而,先前在全球和区域尺度上的命运建模主要基于八方向算法,而不区分污染源。该算法无法表征通过地下管道和废水处理基础设施的点源排放的命运路径,并且在考虑由河流分叉引起的多向路径方面表现出次优的性能,尤其是在平坦的地形。在这里,我们旨在通过结合各种命运路径和解决多方向场景来改善命运建模。我们还通过补充潜在的未经处理的点源排放(PSu)来更新P估计值。在太湖流域快速城市化地区研究了改进的方法,中国2017年的空间分辨率为100m×100m。结果表明,PSu对FEP的贡献(62.6%)大于对P排放的贡献(58.5%)。通过改进的命运建模,FEP在空间上分布更广泛,促进根据当地情况制定有针对性的监管策略。
    Excessive anthropogenic phosphorus (P) emissions put constant pressure on aquatic ecosystems. This pressure can be quantified as the freshwater eutrophication potential (FEP) by linking P emissions, P fate in environmental compartments, and the potentially disappeared fraction of species due to increase of P concentrations in freshwater. However, previous fate modeling on global and regional scales is mainly based on the eight-direction algorithm without distinguishing pollution sources. The algorithm fails to characterize the fate paths of point-source emissions via subsurface pipelines and wastewater treatment infrastructure, and exhibits suboptimal performance in accounting for multidirectional paths caused by river bifurcations, especially in flat terrains. Here we aim to improve the fate modeling by incorporating various fate paths and addressing multidirectional scenarios. We also update the P estimates by complementing potential untreated point-source emissions (PSu). The improved method is examined in a rapidly urbanizing area in Taihu Lake Basin, China in 2017 at a spatial resolution of 100 m × 100 m. Results show that the contribution of PSu on FEP (62.6%) is greater than that on P emissions (58.5%). The FEP is more spatially widely distributed with the improved fate modeling, facilitating targeted regulatory strategies tailored to local conditions.
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  • 文章类型: Journal Article
    针对COVID-19的疫苗接种是控制随着SARS-CoV-2变体的持续出现而持续存在的大流行的不可或缺的一部分。使用描述SARS-CoV-2宿主内感染动力学的数学模型,我们估计由于感染变异因素而导致的病毒和免疫差异,年龄,和疫苗接种史(疫苗接种品牌,接种疫苗后的剂量和时间)。我们在贝叶斯框架中将我们的模型拟合到从新加坡的Delta和Omicron感染病例获得的上呼吸道病毒载量测量,其中大多数人只有一个鼻咽拭子测量。有了这个数据集,我们能够重现在适合纵向患者数据的过去宿主内建模研究中观察到的URT病毒动力学的相似趋势.我们发现Omicron的R0高于Delta,表明宿主内感染的初始细胞间扩散更大。此外,通过将免疫相关参数拟合为疫苗接种史特异性,可以重建患者亚组之间感染动力学的异质性,有或没有年龄的修改。我们的模型结果与老年人SARS-CoV-2感染的免疫衰老的概念一致,以及自上次疫苗接种以来免疫力随着时间的增加而下降的问题。最后,在Omicron感染和Delta感染中,未发现疫苗接种会抑制病毒动力学。这项研究提供了有关疫苗引发的免疫对SARS-CoV-2宿主内动力学的影响的见解。以及年龄和疫苗接种史之间的相互作用。此外,它表明需要解开宿主因素和病原体的变化,以辨别影响病毒动态的因素。最后,这项工作展示了研究宿主内病毒动力学的前进道路,通过使用包括大量患者的病毒载量数据集,无需重复测量。
    Vaccination against COVID-19 was integral to controlling the pandemic that persisted with the continuous emergence of SARS-CoV-2 variants. Using a mathematical model describing SARS-CoV-2 within-host infection dynamics, we estimate differences in virus and immunity due to factors of infecting variant, age, and vaccination history (vaccination brand, number of doses and time since vaccination). We fit our model in a Bayesian framework to upper respiratory tract viral load measurements obtained from cases of Delta and Omicron infections in Singapore, of whom the majority only had one nasopharyngeal swab measurement. With this dataset, we are able to recreate similar trends in URT virus dynamics observed in past within-host modelling studies fitted to longitudinal patient data.We found that Omicron had higher R0,within values than Delta, indicating greater initial cell-to-cell spread of infection within the host. Moreover, heterogeneities in infection dynamics across patient subgroups could be recreated by fitting immunity-related parameters as vaccination history-specific, with or without age modification. Our model results are consistent with the notion of immunosenescence in SARS-CoV-2 infection in elderly individuals, and the issue of waning immunity with increased time since last vaccination. Lastly, vaccination was not found to subdue virus dynamics in Omicron infections as well as it had for Delta infections.This study provides insight into the influence of vaccine-elicited immunity on SARS-CoV-2 within-host dynamics, and the interplay between age and vaccination history. Furthermore, it demonstrates the need to disentangle host factors and changes in pathogen to discern factors influencing virus dynamics. Finally, this work demonstrates a way forward in the study of within-host virus dynamics, by use of viral load datasets including a large number of patients without repeated measurements.
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  • 文章类型: Journal Article
    夏令时(DST)目前在许多国家/地区使用,其理由是它可以增强白天时间与人口活动高峰之间的一致性。转换进入和离开DST的行为引入了昼夜节律的中断,从而影响睡眠和整体健康。尽管受影响的人数众多,这种昼夜节律中断的后果经常被忽视。这里,我们使用人类昼夜节律起搏器的数学模型来阐明生物钟如何与白天和晚上暴露在自然光和电灯下的相互作用。这种相互作用在确定对DST转换或从DST转换所施加的1小时时区转换的适应中起着至关重要的作用。在关于DST的全球讨论中,尽管一些研究表明人类昼夜节律系统需要几天才能完全适应DST过渡,但人们普遍认为个体很容易适应DST过渡。我们的研究强调,夜间光照变化可能是重新夹带的主要驱动力,与时间生物学模型预测,与具有较短的固有期(即较晚的时间型)的人相比,具有较长的固有期(即较晚的时间型)的人向DST过渡或从DST过渡的速度更慢。此外,该模型预测适应速度的个体间差异很大,特别是在弹簧过渡期间。从我们的模型中得出的预测为基于昼夜节律的光照策略提供了建议,这些建议有助于更快速地适应与DST相关的过渡或跨单个时区旅行。因此,我们的研究为正在进行的DST及其对人类昼夜节律的影响提供了有价值的见解。
    Daylight saving time (DST) is currently utilized in many countries with the rationale that it enhances the alignment between daylight hours and activity peaks in the population. The act of transitioning into and out of DST introduces disruptions to the circadian rhythm, thereby impacting sleep and overall health. Despite the substantial number of individuals affected, the consequences of this circadian disruption have often been overlooked. Here, we employ a mathematical model of the human circadian pacemaker to elucidate how the biological clock interacts with daytime and evening exposures to both natural and electrical light. This interaction plays a crucial role in determining the adaptation to the 1 hour time zone shift imposed by the transition to or from DST. In global discussions about DST, there is a prevailing assumption that individuals easily adjust to DST transitions despite a few studies indicating that the human circadian system requires several days to fully adjust to a DST transition. Our study highlights that evening light exposure changes can be the main driving force for re-entrainment, with chronobiological models predicting that people with longer intrinsic period (i.e. later chronotype) entrain more slowly to transitions to or from DST as compared to people with a shorter intrinsic period (earlier chronotype). Moreover, the model forecasts large inter-individual differences in the adaptation speed, in particular during the spring transition. The predictions derived from our model offer circadian biology-based recommendations for light exposure strategies that facilitate a more rapid adaptation to DST-related transitions or travel across a single time zone. As such, our study contributes valuable insights to the ongoing discourse on DST and its implications for human circadian rhythms.
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