一种耦合LSTM算法和云模型的疫情传播风险预测模型     

李照  高惠瑛  代晓奕  孙海 《地球信息科学学报》2021,23(11):1924-1925

模拟传染病时空传播、定量评估疫情风险对科学防控、精准施策具有重要的现实意义。本文融合多源时空数据,构建了耦合LSTM算法和云模型的疫情传播风险预测模型。该模型首先基于GIS和LSTM算法构建疫情空间演变模拟模型,通过学习历史疫情数据中的规律,以1 km×1 km为空间尺度、天为时间尺度模拟传染病时空传播过程。其次,基于模拟传染病例数据和疫情传播时空影响因素构建风险评价指标,应用云模型和自适应策略构建疫情风险评估模型,实现多空间尺度的疫情风险评价。在实证研究阶段,应用该模型对北京2020年6月份突发COVID-19疫情空间演变过程进行模拟和风险评估,并引入常规机器学习模型作比较验证。结果表明：应用于疫情时空传播模拟,相较其它常规的机器学习模型,考虑时序关系的LSTM模型的模拟精度更高（MAE为0.00261）,拟合度更好（R-square为0.9455）;耦合模型不仅能充分考虑传染源因素、天气因素、疫情扩散因素及疫情防御因素对疫情风险传播的影响,反映风险演变趋势,还能快速量化区域风险等级,实现不同空间分辨率下的疫情风险评估。因此,基于LSTM算法和云模型的耦合模型可有效预测疫情的传播风险,同时,也为传染病时空传播建模与风险评估提供了方法参考。  相似文献   

Application of a memory surface model to predict whole-life settlements of a sliding foundation     

《Computers and Geotechnics》2017

In this paper a novel modelling procedure is proposed to estimate whole-life settlements of tolerably mobile sliding foundations. A new kinematic hardening-critical state-state parameter constitutive model, the Memory Surface Hardening model, is implemented in a one-dimensional analysis to predict accumulated vertical settlements under drained lateral cyclic loading. The Memory Surface Hardening model performance is compared with the Modified Cam Clay and Severn-Trent Sand models. The Memory Surface Hardening model is adopted to simulate available experimental data from centrifuge tests to predict the settlement of a sliding foundation at the final stable state (i.e. no further volume changes occur).  相似文献   

(Re)Connecting spatial literacy with children’s geographies: GPS,Google Earth and children’s everyday lives     

《Geoforum》2017

This article sets out an agenda for research that (re)connects research on children’s geographies and childhood studies with studies of spatial literacy. Research on children’s environmental cognition and, latterly, spatial literacy, has been artificially and problematically separated from the majority of research in childhood studies. Our fundamental aim in this article is to argue for – and to evidence – greater attention to how spatial literacy and children’s everyday lives are embedded in one another. To support our broader call for a synthetic research agenda, we draw on some more focussed, qualitative empirical material taken from a large-scale project about children’s mobilities and everyday lives in newly-built urban communities. Our analysis focuses upon children’s interpretations of Global Positioning Systems (GPS) tracks of their mobilities, set against a background of Google Earth imagery. In doing so, we showcase one suite of ways in which research on environmental cognition and children’s geographies might proceed together. We demonstrate that children not only displayed analytical skills (for instance, in relation to scaling effects and pattern recognition) but that many also exercised higher-level, critical analysis, especially in relation to errors on Google Earth outputs. Simultaneously, we interrogate the recursive articulation of a range of qualitative indicators of spatial literacy, with children’s everyday mobilities, routines, emotions and memories. The paper analyses how new conceptual languages and technologies being propounded by spatial literacy scholars could afford a more enriched understanding of key contemporary concerns for children’s geographers, and, recursively, what spatial literacy scholars might gain from engaging with (especially qualitative) research prompted by those concerns.  相似文献   

基于BiLSTM-CRF的中文层级地址分词     

程博  李卫红  童昊昕 《地球信息科学学报》2019,21(8):1143-1151

中文地址分词是中文地址标准化的基础工作和地理编码的重要手段,同时也是中文分词和地理研究领域中关注的热点问题之一。针对当前中文地址分词方法缺乏地址层级切分和过多依赖词典和特征的问题,本研究结合四词位标注集和中文层级地址特点,构建针对中文层级地址分词的地址标注体系,并提出融合双向长短时记忆网络和条件随机场(BiLSTM-CRF)的中文层级地址分词模型。该模型既考虑了BiLSTM模型能够记忆上下文地址的特性,也保留了CRF算法可以通过转移概率矩阵控制地址标注输出的能力。针对该地址标注体系标注的训练地址样本,分别使用CRF、LSTM、BiLSTM与BiLSTM-CRF模型进行训练对比。结果表明：① 基于中文地址标注体系的模型分词效果更佳,地址标注更为精细,符合实际地址分布情况;② BiLSTM-CRF模型精确度达到93.4%,高于CRF（90.4%）、LSTM（89.3%）和BiLSTM（91.2%）,其整体地址分词性能和各层级地址分词效果相对于其他模型更突出;③ 各模型分词性能与地址层级保持一致,即地址层级越高,分词效果越好。本研究提出的中文地址标注体系和分词模型为开展中文地址标准化工作提供了方法参考,同时也为进一步提升地理编码技术的精准度提供了可能。  相似文献   

Aeromonas veronii, a tributyltin (TBT)-degrading bacterium isolated from an estuarine environment, Ria de Aveiro in Portugal   总被引：1，自引：0，他引：1  

Cruz A  Caetano T  Suzuki S  Mendo S 《Marine environmental research》2007,64(5):639-650

Organotin compounds are used in a variety of industrial processes therefore their subsequent discharge into the environment is widespread. Bacteria play an important role in biogeochemical transformations acting as natural decontamination agents. Therefore, screening for tributyltin (TBT)-resistant and -degrading bacteria is relevant for the selection of isolates with decontamination ability of these polluted areas. With this purpose, 50 strains were isolated from sediment and water from Ria de Aveiro and their tolerance to TBT, up to 3mM, was evaluated. Generally, occurrence of highly TBT-resistant bacteria was observed, and Gram negative bacteria exhibited more tolerance to TBT than Gram positive bacteria. A memory response was observed when bacteria were progressively exposed to increasingly higher TBT concentrations. One isolate, Aeromonas veronii Av27, highly resistant to TBT (3mM) uses this compound as carbon source and degrades it to less toxic compounds.  相似文献   

Looking for the future in the rubble of Palmyra: Destruction,reconstruction and identity     

《Geoforum》2016

The destruction of the ancient ruins of Palmyra by the terrorist group Islamic State (IS) in September 2015 shocked the world, with some going so far as to decry it as a war crime. This paper explores why the razing of Palmyra resonated so strongly with the international community, demonstrating how the relationship between urban space and collective memory made this event so powerful. Looking to the future, it suggests that the toughest test for Palmyra is yet to come. The challenge of post-conflict reconstruction in sites such as this is inextricably bound up with questions of identity, memory and power, all of which will need to be worked out when the war in Syria eventually comes to an end.  相似文献   

Angels of memory: photography and haunting in Guatemala City     

Steven Hoelscher 《GeoJournal》2008,73(3):195-217

This article explores the relationship between historical memory, urban space, and photography by way of a case study: the place-specific public art of the Guatemalan photographer and human rights activist, Daniel Hernández-Salazar. As one of a growing number of Latin American artists committed to combating the “institutionalized forgetfulness” of human rights violations throughout the hemisphere, Hernández-Salazar deploys geographically-rich photographic installations to help his society remember its difficult past. The installations, known as Street Angel, are like ghosts haunting the graves of the murdered, fortresses of the powerful, bastions of the complicit. By shedding light on these ghostly angels, this article reveals the important role of photography, as a crucial vehicle of memory, in bearing witness to the unimaginable horrors that consumed much of the twentieth century, as well as that technology’s limitations. It also shows how remembrances of those atrocities depend on urban space for their grounding, articulation, and maintenance. Finally, by probing the artistic impulse and political sensibility that created Guatemala City’s angels of memory, it makes the case that, in the combustible political climate of post-war Central America, the work of remembering the past is not an antiquarian exercise: the labor of memory is a fundamental component of building a just society.

Steven HoelscherEmail:

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Movement,memory, landscape: an excursion in non-representational thought     

Kevin E. McHugh 《GeoJournal》2009,74(3):209-218

This paper is an excursion in non-representational thought. The primacy of movement charges this creative geography. Movement as sensation, thought, matter and memory crystallizes in ongoing assemblages (effects) we term selves and landscapes. This movement ontology is animated by a stream of thought running through Bergson, Deleuze, and Massumi, and by Ingold’s temporality of landscape. Memory is vital, as past (virtual) and present (actual) coexist, pushing forward in duration, the dynamic continuation of movement and sensation. David Lynch’s film, The Straight Story, offers dramatic illustration of the entanglement of movement, memory, and landscape. Landscape is emergent as relational lines of movement, an ongoing meshwork of practices and movement signatures. Alvin Straight’s paced journey through Iowa on a John Deere lawn mower during autumn harvest is a road to reminiscence and reconciliation, an American sublime. Lynch’s movement-images and soundscapes are sensorial undulations that illumine landscape as movement of incorporation, ‘dwelling’ in the moment to moment, geographies of care. The take-home message is that we are nothing more and nothing less than agents, next selves, ‘passing’ through. The collective trace of our ‘passings’ constitutes the making and remaking of place.

Kevin E. McHughEmail:

  相似文献   

煤岩变形破坏电磁辐射记忆效应实验研究   总被引：6，自引：1，他引：6       下载免费PDF全文

撒占友  何学秋  王恩元  于广明 《地球物理学报》2005,48(2):379-385

实验研究了原煤、型煤单轴压缩电磁辐射记忆效应特征、记忆内容及变化规律，探讨并分析了煤岩电磁辐射记忆效应机理.结果表明，煤岩变形破坏电磁辐射具有记忆先期最大应力、纵向应变、横向应变和体应变的能力，最直接的记忆内容是先期受到的应力、纵向应变和横向应变；当先期施加的应力水平大于70%～80%时，电磁辐射记忆能力迅速减弱，甚至根本失去记忆能力；煤岩损伤破坏过程的不可逆决定了电磁辐射过程的不可逆，电磁辐射过程的不可逆是煤岩变形破坏电磁辐射记忆效应的直接原因.煤岩电磁辐射记忆效应理论在地应力测试、巷道围岩不同应力区范围的确定及煤岩动力灾害预测等方面具有广阔的应用前景.  相似文献   

Influence of a cyclic and dynamic loading history on dynamic properties of dry sand, part I: cyclic and dynamic torsional prestraining     

T. Wichtmann  Th. Triantafyllidis 《Soil Dynamics and Earthquake Engineering》2004,24(2):127-147

Initial fabric of a soil induced by its cyclic strain history is an important parameter together with the void ratio, state of stress and amplitude in respect to further accumulation of deformations under drained cyclic loading. It is of importance for the further deformation prediction to determine the initial fabric of the grain skeleton or the cyclic loading history of the soil. An attempt is made within this paper to correlate small strain stiffness of non-cohesive soil with its cyclic loading history. The results of performed cyclic and dynamic torsional tests show that small strain shear modulus is only moderately affected by cyclic prestraining even if high amplitudes are applied. A signature of prestraining history is observed in the tests since the sand memorizes its prestraining amplitude and the number of applied cycles.  相似文献