To see the other types of publications on this topic, follow the link: Structure analysis – Prognostic spatial modelling.
Journal articles on the topic 'Structure analysis – Prognostic spatial modelling'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Structure analysis – Prognostic spatial modelling.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Ponzano, Matteo, Bruno Joly, Laurent Descamps, and Philippe Arbogast. "Systematic error analysis of heavy-precipitation-event prediction using a 30-year hindcast dataset." Natural Hazards and Earth System Sciences 20, no. 5 (May 20, 2020): 1369–89. http://dx.doi.org/10.5194/nhess-20-1369-2020.
Full textAbstract:
Abstract. The western Mediterranean region is prone to devastating flash floods induced by heavy-precipitation events (HPEs), which are responsible for considerable human and material losses. Quantitative precipitation forecasts have improved dramatically in recent years to produce realistic accumulated rainfall estimations. Nevertheless, there are still challenging issues which must be resolved to reduce uncertainties in the initial condition assimilation and the modelling of physical processes. In this study, we analyse the HPE forecasting ability of the multi-physics-based ensemble model Prévision d’Ensemble ARPEGE (PEARP) operational at Météo-France. The analysis is based on 30-year (1981–2010) ensemble hindcasts which implement the same 10 physical parameterizations, one per member, run every 4 d. Over the same period a 24 h precipitation dataset is used as the reference for the verification procedure. Furthermore, regional classification is performed in order to investigate the local variation in spatial properties and intensities of rainfall fields, with a particular focus on HPEs. As grid-point verification tends to be perturbed by the double penalty issue, we focus on rainfall spatial pattern verification thanks to the feature-based quality measure of structure, amplitude, and location (SAL) that is performed on the model forecast and reference rainfall fields. The length of the dataset allows us to subsample scores for very intense rainfall at a regional scale and still obtain a significant analysis, demonstrating that such a procedure is consistent to study model behaviour in HPE forecasting. In the case of PEARP, we show that the amplitude and structure of the rainfall patterns are basically driven by the deep-convection parametrization. Between the two main deep-convection schemes used in PEARP, we qualify that the Prognostic Condensates Microphysics and Transport (PCMT) parametrization scheme performs better than the B85 scheme. A further analysis of spatial features of the rainfall objects to which the SAL metric pertains shows the predominance of large objects in the verification measure. It is for the most extreme events that the model has the best representation of the distribution of object-integrated rain.
2
Pritchard, David M. W., Nathan Forsythe, Greg O'Donnell, Hayley J. Fowler, and Nick Rutter. "Multi-physics ensemble snow modelling in the western Himalaya." Cryosphere 14, no. 4 (April 14, 2020): 1225–44. http://dx.doi.org/10.5194/tc-14-1225-2020.
Full textAbstract:
Abstract. Combining multiple data sources with multi-physics simulation frameworks offers new potential to extend snow model inter-comparison efforts to the Himalaya. As such, this study evaluates the sensitivity of simulated regional snow cover and runoff dynamics to different snowpack process representations. The evaluation is based on a spatially distributed version of the Factorial Snowpack Model (FSM) set up for the Astore catchment in the upper Indus basin. The FSM multi-physics model was driven by climate fields from the High Asia Refined Analysis (HAR) dynamical downscaling product. Ensemble performance was evaluated primarily using MODIS remote sensing of snow-covered area, albedo and land surface temperature. In line with previous snow model inter-comparisons, no single FSM configuration performs best in all of the years simulated. However, the results demonstrate that performance variation in this case is at least partly related to inaccuracies in the sequencing of inter-annual variation in HAR climate inputs, not just FSM model limitations. Ensemble spread is dominated by interactions between parameterisations of albedo, snowpack hydrology and atmospheric stability effects on turbulent heat fluxes. The resulting ensemble structure is similar in different years, which leads to systematic divergence in ablation and mass balance at high elevations. While ensemble spread and errors are notably lower when viewed as anomalies, FSM configurations show important differences in their absolute sensitivity to climate variation. Comparison with observations suggests that a subset of the ensemble should be retained for climate change projections, namely those members including prognostic albedo and liquid water retention, refreezing and drainage processes.
3
Barbu, A. L., J. C. Calvet, J. F. Mahfouf, and S. Lafont. "Integrating ASCAT surface soil moisture and GEOV1 leaf area index into the SURFEX modelling platform: a land data assimilation application over France." Hydrology and Earth System Sciences Discussions 10, no. 7 (July 11, 2013): 9057–103. http://dx.doi.org/10.5194/hessd-10-9057-2013.
Full textAbstract:
Abstract. The land monitoring service of the European Copernicus programme has developed a set of satellite-based biogeophysical products, including surface soil moisture (SSM) and leaf area index (LAI). This study investigates the impact of joint assimilation of remotely sensed SSM derived from ASCAT backscatter data and the GEOV1 satellite-based LAI into the ISBA-A-gs land surface model within the SURFEX modelling platform of Meteo-France. The ASCAT data were bias corrected with respect to the model climatology by using a seasonal-based CDF (Cumulative Distribution Function) matching technique. A multivariate multi-scale land data assimilation system (LDAS) based on the Extended Kalman Filter (EKF) is used for monitoring the soil moisture, terrestrial vegetation, surface carbon and energy fluxes across the France domain at a spatial resolution of 8 km. Each model grid box is divided in a number of land covers, each having its own set of prognostic variables. The filter algorithm is designed to provide a distinct analysis for each land cover while using one observation per grid box. The updated values are aggregated by computing a weighted average. In this study, it is demonstrated that the assimilation scheme works effectively within the ISBA-A-gs model over a four-year period (2008–2011). The EKF is able to extract useful information from the data signal at the grid scale and to distribute the root-zone soil moisture and LAI increments among the mosaic structure of the model. The impact of the assimilation on the vegetation phenology and on the water and carbon fluxes varies from one season to another. The spring drought of 2011 is an interesting case study showing the potential of the assimilation to improve drought monitoring. A comparison between simulated and in situ soil moisture gathered at the twelve SMOSMANIA stations shows improved anomaly correlations for eight stations.
4
Barbu, A. L., J. C. Calvet, J. F. Mahfouf, and S. Lafont. "Integrating ASCAT surface soil moisture and GEOV1 leaf area index into the SURFEX modelling platform: a land data assimilation application over France." Hydrology and Earth System Sciences 18, no. 1 (January 14, 2014): 173–92. http://dx.doi.org/10.5194/hess-18-173-2014.
Full textAbstract:
Abstract. The land monitoring service of the European Copernicus programme has developed a set of satellite-based biogeophysical products, including surface soil moisture (SSM) and leaf area index (LAI). This study investigates the impact of joint assimilation of remotely sensed SSM derived from Advanced Scatterometer (ASCAT) backscatter data and the Copernicus Global Land GEOV1 satellite-based LAI product into the the vegetation growth version of the Interactions between Soil Biosphere Atmosphere (ISBA-A-gs) land surface model within the the externalised surface model (SURFEX) modelling platform of Météo-France. The ASCAT data were bias corrected with respect to the model climatology by using a seasonal-based CDF (Cumulative Distribution Function) matching technique. A multivariate multi-scale land data assimilation system (LDAS) based on the extended Kalman Filter (EKF) is used for monitoring the soil moisture, terrestrial vegetation, surface carbon and energy fluxes across the domain of France at a spatial resolution of 8 km. Each model grid box is divided into a number of land covers, each having its own set of prognostic variables. The filter algorithm is designed to provide a distinct analysis for each land cover while using one observation per grid box. The updated values are aggregated by computing a weighted average. In this study, it is demonstrated that the assimilation scheme works effectively within the ISBA-A-gs model over a four-year period (2008–2011). The EKF is able to extract useful information from the data signal at the grid scale and distribute the root-zone soil moisture and LAI increments throughout the mosaic structure of the model. The impact of the assimilation on the vegetation phenology and on the water and carbon fluxes varies from one season to another. The spring drought of 2011 is an interesting case study of the potential of the assimilation to improve drought monitoring. A comparison between simulated and in situ soil moisture gathered at the twelve SMOSMANIA (Soil Moisture Observing System–Meteorological Automatic Network Integrated Application) stations shows improved anomaly correlations for eight stations.
5
Zhu, Wenyue, Jae Yee Ku, Yalin Zheng, Paul C. Knox, Ruwanthi Kolamunnage-Dona, and Gabriela Czanner. "Spatial Linear Mixed Effects Modelling for OCT Images: SLME Model." Journal of Imaging 6, no. 6 (June 5, 2020): 44. http://dx.doi.org/10.3390/jimaging6060044.
Full textAbstract:
Much recent research focuses on how to make disease detection more accurate as well as “slimmer”, i.e., allowing analysis with smaller datasets. Explanatory models are a hot research topic because they explain how the data are generated. We propose a spatial explanatory modelling approach that combines Optical Coherence Tomography (OCT) retinal imaging data with clinical information. Our model consists of a spatial linear mixed effects inference framework, which innovatively models the spatial topography of key information via mixed effects and spatial error structures, thus effectively modelling the shape of the thickness map. We show that our spatial linear mixed effects (SLME) model outperforms traditional analysis-of-variance approaches in the analysis of Heidelberg OCT retinal thickness data from a prospective observational study, involving 300 participants with diabetes and 50 age-matched controls. Our SLME model has a higher power for detecting the difference between disease groups, and it shows where the shape of retinal thickness profiles differs between the eyes of participants with diabetes and the eyes of healthy controls. In simulated data, the SLME model demonstrates how incorporating spatial correlations can increase the accuracy of the statistical inferences. This model is crucial in the understanding of the progression of retinal thickness changes in diabetic maculopathy to aid clinicians for early planning of effective treatment. It can be extended to disease monitoring and prognosis in other diseases and with other imaging technologies.
6
Bennett, R. J., and R. P. Haining. "Spatial Structure and Spatial Interaction: Modelling Approaches to the Statistical Analysis of Geographical Data." Journal of the Royal Statistical Society. Series A (General) 148, no. 1 (1985): 1. http://dx.doi.org/10.2307/2981508.
Full text
7
Soulié, M., P. Montes, and V. Silvestri. "Modelling spatial variability of soil parameters." Canadian Geotechnical Journal 27, no. 5 (October 1, 1990): 617–30. http://dx.doi.org/10.1139/t90-076.
Full textAbstract:
The purpose of this study is to show that geostatistics can help in finding the structure of the spatial variability of the undrained shear strength within a clay deposit. The site under study, B-6, owes its name to the earth dam that will be constructed on it; the site is located on the shore of the Broadback River in the James Bay area of Quebec. The geostatistical analysis is carried out on the unaltered zone of the B-6 clay; it shows an anisotropic structure for the spatial variability. The knowledge of the structure (variogram) of the undrained shear strength is used in the kriging theory to compute estimations at points of the deposit where experimental measurements are not available. Kriging is also used to identify weak zones within the B-6 clay. The geostatistical analysis of the B-6 clay gives the opportunity to test the capability of the method. Even if the errors of measurements were small, the variogram has permitted detection and correction of a bias that affected a certain number of vane profiles. Key words: clay, geostatistics, undrained shear strength, variogram, measurements errors, kriging.
8
Zimeras, Stelios, and Yiannis Matsinos. "Spatial Uncertainty Analysis in Ecological Biology." International Journal of Systems Biology and Biomedical Technologies 2, no. 1 (January 2013): 14–24. http://dx.doi.org/10.4018/ijsbbt.2013010102.
Full textAbstract:
Uncertainty analysis is the part of risk analysis that focuses on the uncertainties in the data characteristics. Important components of uncertainty analysis include qualitative analysis that identifies the uncertainties, quantitative analysis of the effects of the uncertainties on the decision process, and communication of the uncertainty. (Funtowwicz & Ravetz 1990; Petersen, 2000; Regan et a1., 2002; Katz 2002). The analyses include simple descriptive procedures till quantitative estimation of uncertainty, and decision-based procedures. The analysis may be qualitative or quantitative, depending on the stage of analysis required and the amount of information available. When a neighbourhood structure lattice system is applied, a spatial connectivity between regions is defined where investigation of that structure includes modelling of the spatial homogeneity is introduced. Spatial investigation involves stochastic modelling especially in cases where the incomplete data involves hide information’s. In this work a spatial analysis methodology was introduced and procedures to solve the problem with spatial variability are described.
9
Chen, Xia, and Jianmin Liu. "Fiscal Decentralization and Environmental Pollution: A Spatial Analysis." Discrete Dynamics in Nature and Society 2020 (March 26, 2020): 1–10. http://dx.doi.org/10.1155/2020/9254150.
Full textAbstract:
Based on annual data over the period 2003 to 2017 covering 31 provinces in China, the environmental pollution index and environmental regulation index are constructed. Moran’s I, the widely used spatial autocorrelation index, is used to analyze the spatial distribution of environmental pollution, which provides a fairly high stability of the positive spatial correlation of environmental pollution. Then, the 0-1 matrix, distance weighting matrix, and economic distance mixed matrix are carried out to weigh space separately. To analyze the impact of fiscal decentralization on environmental pollution, the spatial Durbin model is employed. In the meanwhile, fiscal decentralization is measured from the perspective of both fiscal expenditure decentralization and fiscal revenue decentralization. The results show that the impact of fiscal decentralization on environmental pollution is positive and appears the phenomenon of “race to bottom.” To improve environmental quality, appropriate environmental regulation target, implementing green GDP accounting, and adjusting economic structure should be adopted.
10
Yakimov, Basil N., Dmitry I. Iudin, Leonid A. Solntsev, and David B. Gelashvili. "Multifractal analysis of neutral community spatial structure." Journal of Theoretical Biology 343 (February 2014): 44–53. http://dx.doi.org/10.1016/j.jtbi.2013.10.011.
Full text
11
Matisziw, T. C., T. H. Grubesic, and H. Wei. "Downscaling spatial structure for the analysis of epidemiological data." Computers, Environment and Urban Systems 32, no. 1 (January 2008): 81–93. http://dx.doi.org/10.1016/j.compenvurbsys.2007.06.002.
Full text
12
Wieland, Ralf, Marion Voss, Xenia Holtmann, Wilfried Mirschel, and Igbekele Ajibefun. "Spatial Analysis and Modeling Tool (SAMT): 1. Structure and possibilities." Ecological Informatics 1, no. 1 (January 2006): 67–76. http://dx.doi.org/10.1016/j.ecoinf.2005.10.005.
Full text
13
Galacho-Jiménez, Federico Benjamín, David Carruana-Herrera, Julián Molina, and José Damián Ruiz-Sinoga. "Tempo-Spatial Modelling of the Spread of COVID-19 in Urban Spaces." International Journal of Environmental Research and Public Health 19, no. 15 (August 8, 2022): 9764. http://dx.doi.org/10.3390/ijerph19159764.
Full textAbstract:
The relationship between the social structure of urban spaces and the evolution of the COVID-19 pandemic is becoming increasingly evident. Analyzing the socio-spatial structure in relation to cases may be one of the keys to explaining the ways in which this contagious disease and its variants spread. The aim of this study is to propose a set of variables selected from the social context and the spatial structure and to evaluate the temporal spread of infections and their different degrees of intensity according to social areas. We define a model to represent the relationship between the socio-spatial structure of the urban space and the spatial distribution of pandemic cases. We draw on the theory of social area analysis and apply multivariate analysis techniques to check the results in the urban space of the city of Malaga (Spain). The proposed model should be considered capable of explaining the functioning of the relationships between societal structure, socio-spatial segregation, and the spread of the pandemic. In this paper, the study of the origins and consequences of COVID-19 from different scientific perspectives is considered a necessary approach to understanding this phenomenon. The personal and social consequences of the pandemic have been exceptional and have changed many aspects of social life in urban spaces, where it has also had a greater impact. We propose a geostatistical analysis model that can explain the functioning of the relationships between societal structure, socio-spatial segregation, and the temporal evolution of the pandemic. Rather than an aprioristic theory, this paper is a study by the authors to interpret the disparity in the spread of the pandemic as shown by the infection data.
14
Olejnik, Alicja. "An Empirical Study Of Productivity Growth In EU28 - Spatial Panel Analysis." Comparative Economic Research. Central and Eastern Europe 17, no. 4 (December 30, 2014): 187–202. http://dx.doi.org/10.2478/cer-2014-0040.
Full textAbstract:
This paper investigates the spatial process of productivity growth in the European Union on the foundations of the theory of New Economic Geography. The proposed model is based on the study of NUTS 2 regions and takes into consideration a spatial weights matrix in order to better describe the structure of spatial dependence between EU regions. Furthermore, our paper attempts to investigate the applicability of some new approaches to spatial modelling including parameterization of the spatial weights matrix. Our study presents an application of the spatial panel model with fixed effects to Fingleton’s theoretical framework. We suggest that the applied approach constitutes an innovation to spatial econometric studies providing additional information hence, a deeper analysis of the investigated problem.
15
Dutkowski, Gregory W., João Costa e Silva, Arthur R. Gilmour, Hubert Wellendorf, and Alexandre Aguiar. "Spatial analysis enhances modelling of a wide variety of traits in forest genetic trials." Canadian Journal of Forest Research 36, no. 7 (July 1, 2006): 1851–70. http://dx.doi.org/10.1139/x06-059.
Full textAbstract:
Spatial analysis of progeny trial data improved predicted genetic responses by more than 10% for around 20 of the 216 variables tested, although, in general, the gains were more modest. The spatial method partitions the residual variance into an independent component and a two-dimensional spatially autocorrelated component and is fitted using REML. The largest improvements in likelihood were for height. Traits that exhibit little spatial structure (stem counts, form, and branching) did not respond as often. The spatial component represented up to 50% of the total residual variance, usually subsuming design-based blocking effects. The autocorrelation tended to be high for growth, indicating a smooth environmental surface, it tended to be small for measures of health, indicating patchiness, and otherwise the autocorrelation was intermediate. Negative autocorrelations, indicating competition, were present in only 10% of diameter measurements for the largest diameter square planted trials, and between nearest trees with rectangular planting at smaller diameters. Bimodal likelihood surfaces indicate that competition may be present, but not dominant, in other cases. Modelling of extraneous effects yielded extra genetic gain only in a few trials with severely asymmetric autocorrelations. Block analysis of resolvable incomplete-block or row–column designs was better than randomized complete-block analysis, but spatial analysis was even better.
16
Hua, Y. P., G. W. Lan, and Y. L. Du. "MULTI-SCALE SPATIAL MODELLING OF ELECTRIC POWER DISTRIBUTION NETWORKS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W10 (February 8, 2020): 1121–25. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w10-1121-2020.
Full textAbstract:
Abstract. The research proposes a multi-scale spatial data model of electric power distribution networks (EPDNs) to address the problem that the single-scale EPDN data cannot meet the needs of data representation and spatial analysis of multiple levels of detail (LODs). This study comprehensively analyses the equipment used in the EPDN, summarizes the detailed information of EPDN elements and constructs a reasonable EPDN structure system. Based on the analysis of a large number of use cases in the operation and maintenance field of EPDN, this research identifies the elements of the graphic data and attribute data relating to the EPDN. According to the needs of different users and different application modes of EPDN data in multi-scale data representation, the EPDN data models are divided into four LODs, and the simplification principle of constructing different LODs is put forward and the elements contained in each LOD are carefully modelled. This study divides the EPDN elements information into graphic attribute and functional attribute, and then the attribute information of the EPDN data models in different LODs is described in detail. In addition, the EPDN data of Yan Shan campus of Guilin University of Technology is modelled with the proposed method, which has achieved good visualization results.
17
Dogančić, Bruno, Marko Jokić, Neven Alujević, and Hinko Wolf. "Structure Preserving Uncertainty Modelling and Robustness Analysis for Spatially Distributed Dissipative Dynamical Systems." Mathematics 10, no. 12 (June 18, 2022): 2125. http://dx.doi.org/10.3390/math10122125.
Full textAbstract:
The paper deals with uncertainty modelling, robust stability and performance analysis of multi-input multi-output (MIMO) reduced order spatially distributed dissipative dynamical systems. While researching the topic of modern robust control of such systems, two key findings were discovered: (i) systematic modelling of the uncertainty and model order reduction (MOR) at the level of a subsystem gives both modelling freedom and the ability for obtaining less conservative uncertainties on the level of a subsystem; (ii) for a special class of interconnected dissipative dynamical systems, uncertainty conservatism at the subsystem level can be reduced—a novel, structure preserving algorithm employing subsystem partitioning and subsystem MOR by means of balanced truncation method (BTM) is used to obtain low-order robustly stable interconnected systems. Such systems are suitable for practical decentralized and distributed robust controller synthesis. Built upon a powerful framework of integral quadratic constraints (IQCs), this approach gives uncertainty modelling flexibility to perform robustness analysis of real world interconnected systems that are usually affected by multiple types of uncertainties at once. The proposed uncertainty modelling procedure and its practical application are presented on the numerical example. A spatially discretized vibration dynamical system comprised of a series of simply supported Euler beams mutually interconnected by springs and dampers is examined. Spatial discretization of the mathematical model is carried out using the finite element method (FEM).
18
LIU, CHAO, QINGLING ZHANG, JAMES HUANG, and WANSHENG TANG. "DYNAMICAL ANALYSIS AND CONTROL IN A DELAYED DIFFERENTIAL-ALGEBRAIC BIO-ECONOMIC MODEL WITH STAGE STRUCTURE AND DIFFUSION." International Journal of Biomathematics 05, no. 02 (March 2012): 1250010. http://dx.doi.org/10.1142/s1793524511001519.
Full textAbstract:
Nowadays, biological resource in prey-predator ecosystem is commercially harvested and sold with aim of achieving economic interest. Furthermore, harvest effort is usually influenced by variation of economic interest of harvesting and spatial heterogeneous environment. In this paper, a delayed differential-algebraic bio-economic model is proposed, which is utilized to investigate interaction and coexistence mechanism of biological population in the harvested ecosystem due to the variation of economic interest of harvesting as well as the change of population spatial diffusion and gestation delay. Local stability analysis of the proposed model without gestation delay and diffusion reveals that there is a phenomenon of singularity induced bifurcation due to the variation of economic interest of harvesting, and state feedback controllers are designed to stabilize the proposed model at the interior equilibrium. Furthermore, local stability of the proposed model with gestation delay and diffusion is studied, which reveals that the interior equilibrium loses its stability at some critical values of gestation delay and corresponding cycle occurs. It is also shown that population spatial diffusion and harvesting have a stabilizing effect on population dynamics. Finally, numerical simulations are carried out to show consistency with theoretical analysis obtained in this paper.
19
Anderson, Taylor, and Suzana Dragićević. "Representing Complex Evolving Spatial Networks: Geographic Network Automata." ISPRS International Journal of Geo-Information 9, no. 4 (April 20, 2020): 270. http://dx.doi.org/10.3390/ijgi9040270.
Full textAbstract:
Many real-world spatial systems can be conceptualized as networks. In these conceptualizations, nodes and links represent system components and their interactions, respectively. Traditional network analysis applies graph theory measures to static network datasets. However, recent interest lies in the representation and analysis of evolving networks. Existing network automata approaches simulate evolving network structures, but do not consider the representation of evolving networks embedded in geographic space nor integrating actual geospatial data. Therefore, the objective of this study is to integrate network automata with geographic information systems (GIS) to develop a novel modelling framework, Geographic Network Automata (GNA), for representing and analyzing complex dynamic spatial systems as evolving geospatial networks. The GNA framework is implemented and presented for two case studies including a spatial network representation of (1) Conway’s Game of Life model and (2) Schelling’s model of segregation. The simulated evolving spatial network structures are measured using graph theory. Obtained results demonstrate that the integration of concepts from geographic information science, complex systems, and network theory offers new means to represent and analyze complex spatial systems. The presented GNA modelling framework is both general and flexible, useful for modelling a variety of real geospatial phenomena and characterizing and exploring network structure, dynamics, and evolution of real spatial systems. The proposed GNA modelling framework fits within the larger framework of geographic automata systems (GAS) alongside cellular automata and agent-based modelling.
20
Tamilmani, Rajesh, and Emmanuel Stefanakis. "Modelling and Analysis of Semantically Enriched Simplified Trajectories Using Graph Databases." Advances in Cartography and GIScience of the ICA 1 (July 3, 2019): 1–8. http://dx.doi.org/10.5194/ica-adv-1-20-2019.
Full textAbstract:
<p><strong>Abstract.</strong> Geospatial databases are utilized in modelling the huge volume of spatial-temporal data generated by tracking moving objects equipped with positioning devices. This data can be used in performing trajectory analysis such as optimum path finding or identification of collision risk. At the same time, this massive data becomes difficult to handle using traditional databases as raw trajectories contain a lot of unnecessary data points. Thus, trajectory simplification techniques are applied to reduce the number of vertices representing a trajectory. However, elimination of intermediate points by simplification process leads to a loss of semantics associated with the trajectories. These semantics are dependent on the application domain. For example, a trajectory of a moving vessel can convey information about time, distances travelled, bearing, or velocity. This research proposes a graph data model that enriches the simplified geometry of trajectories with the semantics lost in the simplification process. Raw trajectories, initially modelled and stored in a PostgreSQL/PostGIS database, are simplified according to both their spatial and temporal characteristics using the Synchronized Euclidean Distance (SED), while the Semantically Enriched Line simpliFication (SELF) data structure is adopted to preserve the semantics of the vertices eliminated in the simplification process. Then, enriched simplified trajectories are transferred to a Neo4j database and modelled in terms of nodes and edges using graphs. Trajectories can then be further processed using Cypher query language and Neo4j spatial procedures. A visualization tool has been developed on top of Neo4j graph database to support the semantic retrieval and visualization of trajectories.</p>
21
Krutskikh, Natalya. "Modelling the Structure of Terrestrial Landscapes in Urban Areas." Quaestiones Geographicae 40, no. 1 (January 29, 2021): 39–49. http://dx.doi.org/10.2478/quageo-2021-0003.
Full textAbstract:
Abstract The study of internal and external factors in the formation of an urban geosystem is determined by its complex structure and multiple connections. Based on geoinformation modelling, an analysis of the landscape structure of the city territory is carried out, which can be a basis for further geoecological research. Morphometric indicators, which make it possible to determine the elementary geochemical landscapes, are indicated according to the data of the digital elevation model. A standardised topographic position index (TPI) is used to determine locations. Spatial zoning according to the type of land use reflects the qualitative features of the external load and technogenic impact. The data on the composition of the lithogenic base show the properties of the depositing medium and determine the natural background. Number of categories of landscapes identified are 58, characterised by a homogeneous geological composition, technogenic load and conditions for the migration of matter. The ratios of various landscape zones have been calculated. The study area as a whole is characterised by the predominance of migration processes over accumulation.
22
GARCÍA DOMÍNGUEZ, LUIS, R. GUEVARA ERRA, RICHARD WENNBERG, and JOSE L. PEREZ VELAZQUEZ. "ON THE SPATIAL ORGANIZATION OF EPILEPTIFORM ACTIVITY." International Journal of Bifurcation and Chaos 18, no. 02 (February 2008): 429–39. http://dx.doi.org/10.1142/s0218127408020379.
Full textAbstract:
The generation and progression of epileptiform activity, especially that associated with ictal paroxysmal neuronal discharges (seizures), is usually studied in terms of its temporal evolution rather than its spatial organization. The characterization of the spatio-temporal dynamics of epileptiform activity represents a major challenge in neuroscience, due to the very intricate nature of brain structure and function. Our study is an initial attempt to reveal the structure hidden under the spatial organization of the synchronization patterns in neuronal activity associated with epilepsy. Analysis of the phase synchronization patterns from magnetoencephalographic recordings in an epileptic patient revealed a decrease in complexity during seizures. Distinct patterns of synchronized activity were observed during interictal and ictal (seizure) activity, and new tools to quantify and visualize the information contained in a synchrony pattern are proposed. The results reported here support previous observations on the high local synchronization in seizures.
23
Skakauskas, Vladas. "ON AGE‐SPACE STRUCTURE OF AN AUTOSOMAL DIPLOID POPULATION DYNAMICS MODEL." Mathematical Modelling and Analysis 3, no. 1 (December 15, 1998): 203–13. http://dx.doi.org/10.3846/13926292.1998.9637103.
Full textAbstract:
We discuss an age‐structured autosomal polylocal multiallelic diploid population dynamics deterministic model taking into account random mating of sexes, females’ pregnancy and its dispersal in whole space. Dispersal mechanism is described by the diffusion one with constant dispersal moduli while the birth moduli depend on the spatial density of the total population with a time delay. It is assumed that the population consists of male, single (nonfertilized) female, and fertilized female subclasses. Using the method of the fundamental solution for the uniformly parabolic second‐order differential operator with bounded Hölder continuous coefficients we prove the existence and uniqueness theorem for the classic solution of the Cauchy problem for this model. We analyze population's growth and decay, too. Mutation is not considered in this paper.
24
Tenzer, Robert, Vladislav Gladkikh, Pavel Novák, and Peter Vajda. "Spatial and Spectral Analysis of Refined Gravity Data for Modelling the Crust–Mantle Interface and Mantle-Lithosphere Structure." Surveys in Geophysics 33, no. 5 (February 3, 2012): 817–39. http://dx.doi.org/10.1007/s10712-012-9173-3.
Full text
25
Fan, Yong, Shengdi Zhang, Zongyi He, Biao He, Haicong Yu, Xiaoxiao Ye, Hao Yang, Xiangmin Zhang, and Zhifeng Chi. "Spatial Pattern and Evolution of Urban System Based on Gravity Model and Whole Network Analysis in the Huaihe River Basin of China." Discrete Dynamics in Nature and Society 2018 (June 27, 2018): 1–11. http://dx.doi.org/10.1155/2018/3698071.
Full textAbstract:
The spatial pattern and evolution of urban system have been hot research issues in the field of urban research. In this paper, the network analysis method based on the gravity model and the related measurements were used to reveal the properties of the spatial pattern and evolution of the urban system in the HRB (Huaihe River Basin) of China. The findings of this study are as follows: During the period from 2006 to 2014, the economic contact between the HRB cities has been strengthened, but the differences between cities have been expanding. In general, the HRB cities have not yet formed a close network structure, and a trend of economic integration has not been found. This paper expresses the spatial pattern and evolution of urban system in an intuitive way and helps to explain the evolution mechanism of urban system. The method was confirmed by empirical research. Because of the operational and visual expression, this method has broad application prospects in the urban system research.
26
Guénard, Guillaume, and Pierre Legendre. "Bringing multivariate support to multiscale codependence analysis: Assessing the drivers of community structure across spatial scales." Methods in Ecology and Evolution 9, no. 2 (September 18, 2017): 292–304. http://dx.doi.org/10.1111/2041-210x.12864.
Full text
27
Russo, M., and V. Russo. "GEOMETRIC ANALYSIS OF A SPACE GRID STRUCTURE BY AN INTEGRATED 3D SURVEY APPROACH." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVI-2/W1-2022 (February 25, 2022): 465–72. http://dx.doi.org/10.5194/isprs-archives-xlvi-2-w1-2022-465-2022.
Full textAbstract:
Abstract. The survey and modeling of spatial grid structures is often a challenging task to solve, due to the many bottlenecks present in the reverse modelling process. Geometrical and material complexity, scale variation, shadows effects, low accessibility, mismatch between similar elements, metrical validation, data management are all critical passages. They must be solved to obtain a reliable data able to solve the system maintenance and intervention requirements. In these cases, in particular, when the structure is difficult to be accessed, it is essential to plan an integrated survey approach. This paper shows how the survey and modelling of an impressive structure was carried out using both TLS and RPAS photogrammetry. After being validated, the data is integrated into a single point cloud that completely describes the structure, eliminating shadow areas and hidden parts. In the modeling process, particular attention was paid to verifying the correspondence between as-built and project. Finally, an element of particular interest is represented by the attempt to recognize the individual construction components belonging to specified geometric and dimensional classes, with the advantage of obtaining a complete model that is as faithful as possible to the real situation of the structure.
28
BIKTASHEV, V. N., A. V. HOLDEN, S. F. MIRONOV, A. M. PERTSOV, and A. V. ZAITSEV. "ON TWO MECHANISMS OF THE DOMAIN STRUCTURE OF VENTRICULAR FIBRILLATION." International Journal of Bifurcation and Chaos 11, no. 04 (April 2001): 1035–51. http://dx.doi.org/10.1142/s0218127401002596.
Full textAbstract:
Analysis of optically recorded irregular electrical wave activity on the surface of the heart during experimentally induced fibrillation reveals a strong local temporal periodicity. The spatial distribution of the dominant temporal frequencies of excitation has a domain organization. The domains are large (≈1 cm 2) and they persist for minutes. We demonstrate that these data can be reproduced in a two-dimensional excitable medium governed by the FitzHugh–Nagumo equations with a spatial inhomogeneity. We identified two potential mechanisms that may contribute to the observed experimental dynamics: coexistence of stable spiral waves with noncommensurate frequencies of rotation, and Wenckebach-like frequency division from a single spiral source due to inhomogeneity. The number of domains is not an index of the number of wave sources. Both mechanisms reproduce the uniformity of the dominant frequency within individual domains and sharp boundaries between domains. The possibility of distinguishing between different mechanisms using Lissajous figures is discussed.
29
Cichulska, Aneta, and Radosław Cellmer. "Analysis of Prices in the Housing Market Using Mixed Models." Real Estate Management and Valuation 26, no. 4 (December 1, 2018): 102–11. http://dx.doi.org/10.2478/remav-2018-0040.
Full textAbstract:
Abstract Hedonic models, commonly applied for analyzing prices in the property market, do not always fulfil their role, mainly due to the application of simplified assumptions concerning the distribution of variables, the nature of relations or spatial heterogeneity. Classical regression models assumed that the variation of the explained variable (price) is explained by the effect of market features (fixed effects) and the residual component. The hierarchical structure of market data, both as regards market segments and the spatial division, suggests that statistical models of prices should also include random effects for selected subgroups of properties and interactions between variables. The mixed model provides an alternative for constructing various regression models for individual groups or for using binary variables within one model. With its appropriate structure, it makes it possible to take into account both the spatial heterogeneity and to examine the effects of individual features on prices within various property groups. It can also identify synergy effects. The article presents the issue of mixed modelling in the property market and an example of its application in a market of dwellings in Olsztyn. The research used transaction data from the price and value register, supplemented with spatial data. The obtained model was compared with classical regression models and geographically weighted regression. The study also covered the usefulness of mixed models in the mass evaluation of properties, and the possibility of using them in spatial analyses and for the development of property value maps.
30
Bazaras, Jonas. "INTERNAL NOISE MODELLING PROBLEMS OF TRANSPORT POWER EQUIPMENT." TRANSPORT 21, no. 1 (March 31, 2006): 19–24. http://dx.doi.org/10.3846/16484142.2006.9638035.
Full textAbstract:
The acoustic analysis of transport vehicles is presented in this article. Two types of vehicles of Russian production (TEP‐60 and M62) were selected for this research. Using ANSYS/Multiphysic software acoustic noise of different power units in the engine sector was simulated. In this paper we present the modelling results of the locomotive internal noise. In ANSYS/Multiphysic anbience the problems of acoustics are solved on the basis of harmonic response analysis by providing harmonic pressure excitation (sine type) at some points of fluid structure and obtaining the pressure distribution in the fluid. By changing the agitation frequency variable sound distribution at the interval of different frequencies is obtained. Constructing the calculation scheme for a three dimensional locomotive model, spatial structure of finite elements is used. The whole construction was described by 3D finite elements FLUID30 designed for a specified acoustic analysis. The presented acoustic calculation model of rolling‐stock cabin allows the evaluation of structural solutions and, in case of emergency, taking extra measures in the process of rolling‐stock design. The results of acoustic calculation were compared with experimental measurements.
31
Malinin, Yuri, Nikolai Grib, Pavel Kuznetsov, and Zhang Ze. "Prediction of the spatial variability of coal-bearing rocks at the Elginsky coal mine." E3S Web of Conferences 192 (2020): 04007. http://dx.doi.org/10.1051/e3sconf/202019204007.
Full textAbstract:
The article presents a brief analysis of the key methods used for spatial modelling of mining and geological indicators describing the composition, structure and state of rock deposits. The main limitations of the analysed methods when applied under real conditions are outlined. It is proposed to overcome these limitations using Markov nonlinear algorithms. By applying the principles of multi-dimensional Markov modelling to a geological object, interval types were determined for modelling mining and geological parameters of the Elginsky coal mine. As an example, the article presents the results of predicting the ash content for the U5 section of the Elginsky coal mine on the basis of one of the cross-sections of the developed three-dimensional model.
32
Zhu, Qing, Kaihua Liao, Yan Xu, Guishan Yang, Shaohua Wu, and Shenglu Zhou. "Monitoring and prediction of soil moisture spatial–temporal variations from a hydropedological perspective: a review." Soil Research 50, no. 8 (2012): 625. http://dx.doi.org/10.1071/sr12228.
Full textAbstract:
Accurate prediction of soil moisture spatial–temporal variations remains critical in agronomic, hydrological, pedological, and environmental studies. Traditional approaches of soil moisture monitoring and prediction have limitations of being time-consuming, labour-intensive, and costly for direct field observation; and having low spatial resolution for remote sensing, and inconsistent accuracy and reliability for landscape feature (e.g. topography, land use, vegetation) modelling. Innovative and effective approaches for accurate soil moisture simulation are needed. Pedological properties, including soil structure, particle size distribution, porosity, horizon, redox feature, and organic matter content, have been accepted as important factors controlling soil moisture and can be potentially used in soil moisture prediction. However, pedological properties mostly lack quantification (e.g. redox feature, horizon, soil structure), and soil sampling and analysis are time-consuming and costly, especially at large spatial scale. These limitations have restricted the utilisation of pedological information to predict soil moisture spatial–temporal variations at different spatial scales. To overcome these difficulties, new tools including geophysical tools and computed tomography, and new methods including mining soil survey information and integrating pedological information with landscape features and modelling, are proposed in this paper.
33
Quiroz-Martínez, Benjamín, Pablo Hernández-Alcántara, David Alberto Salas-de-León, and Vivianne Solís-Weiss. "Polychaete (Annelida) Diversity Patterns in Southern Gulf of Mexico: The Influence of Spatial Structure and Environmental Variables." Diversity 13, no. 9 (September 3, 2021): 425. http://dx.doi.org/10.3390/d13090425.
Full textAbstract:
A comprehensive database was built to examine the spatial diversity patterns of polychaete species from the continental shelf in Southern Gulf of Mexico. Using Cluster and nMDS analysis we found the composition of polychaete species to be different between the terrigenous and carbonate regions of the Gulf. To test the relative importance of spatial and environmental components in the polychaetae community structure in the Southern Gulf of Mexico, we examined the spatial relationships between polychaetae assemblages and environmental variables over broad geographical scales. A distance-based redundancy analysis (dbRDA) and variation partitioning was used to quantify the relative importance of these explanatory variables on the spatial variations of species richness and composition. Variation partitioning is an important tool to investigate the importance of spatial structure to species distribution in communities, but it has not yet been used in marine ecosystems. The significance level of spatial and environmental components to the distribution of polychaete species showed that the combined effect of spatial processes and sediment characteristics explained a higher percentage of variance than those parameters could alone.
34
Kirste, L., K. M. Pavlov, S. T. Mudie, V. I. Punegov, and N. Herres. "Analysis of the mosaic structure of an ordered (Al,Ga)N layer." Journal of Applied Crystallography 38, no. 1 (January 19, 2005): 183–92. http://dx.doi.org/10.1107/s0021889804030675.
Full textAbstract:
The mosaic structure of an (Al,Ga)N layer grown on (0001) sapphire showing natural ordering was studied by high-resolution X-ray diffraction (HRXRD) reciprocal-space mapping. The direction-dependent mosaicity of the layer has been elaborated using maps of symmetrical and asymmetrical reflections. The reciprocal-lattice points show significant broadening depending on the direction in reciprocal space, the diffraction order and the reflection type (fundamental or superstructural). The evaluation followed two paths: (i) a procedure based on the Williamson–Hall plot and (ii) a new approach based on the statistical diffraction theory (SDT). Here, the transformed Takagi equations were implemented for the simulation of the reciprocal-space maps (RSM) for symmetrical and asymmetrical reflections. The reconstruction comprised the mosaic block size, their average rotation angle and the spatial distribution of some components of the microdistortion tensor. The results based on the SDT modelling agree well with those obtained by the Williamson–Hall method, while providing a higher degree of precision and detail.
35
Moskvichev, Egor. "Distribution of material properties in finite element models of inhomogeneous elements of structures." EPJ Web of Conferences 221 (2019): 01034. http://dx.doi.org/10.1051/epjconf/201922101034.
Full textAbstract:
This paper discusses an approach to finite element modelling of structure elements considering material inhomogeneity. This approach is based on the functional dependence of mechanical properties on the spatial coordinates of finite elements. It allows modelling gradient transitions between different materials, which avoid stress discontinuities during strength analysis. The finite element models of cold formed angle, welded joint and thermal barrier coating, created by this method, have been presented.
36
Chen, Shaopei, Dachang Zhuang, and Huixia Zhang. "Urban Metro Network Topology Evolution and Evaluation Modelling Based on Complex Network Theory: A Case Study of Guangzhou, China." MATEC Web of Conferences 232 (2018): 01034. http://dx.doi.org/10.1051/matecconf/201823201034.
Full textAbstract:
As urban metro network is generally referred as a significant component of the modem urban transport system, the spatiotemporal evolution of spatial layout and topology structure of the network should be investigated and evaluated in order to promote urban transport services and optimize urban spatial pattern. This paper takes a case study of the city of Guangzhou, China, and applies the complex network theory and integrates geography information system (GIS) to explore and discuss the growth and topological structure characteristics of the Guangzhou metro network. Importantly, this paper focuses on accessing the formation process of the topology structure of the Guangzhou metro network from 1997 to 2016 on the basis of spatio-temporal sequence data analysis. This aims to provide scientific references for the future development and planning of urban metro network in China.
37
Zaleckis, Kestutis, Ausra Mlinkauskiene, and Nijole Steponaityte. "Research on Changes of Spatial Structure Genotype of a Former Artillerymen’ Military Town of Kaunas Fortress." Landscape architecture and art 16 (December 30, 2020): 16–30. http://dx.doi.org/10.22616/j.landarchart.2020.16.02.
Full textAbstract:
Immovable cultural heritage creates a background for sustainable cultural development of cities. As a cultural artefact, it appears in two-fold situation in the above-mentioned context. Firstly, the continuity of the valuable features as carriers of cultural content should be preserved. Secondly, the possibility of the evolution (functional, spatial or social) of the object should be assured. Now the valuable features of the immovable cultural heritage are described in a static, quantitative ways with focus on phenotype, e.g. spatial volume, place, details of architectural style, number and places of windows, etc. Such type of description without any argumentations is practically closing any possibilities for further evolution of the protected objects. It is especially true if we speak about urban valuable structures. The authors of the article present a proposal for dynamic, genotype oriented modelling of the possible evolution of the former military town of Kaunas Fortress as an example of immovable urban cultural heritage. The model is based on the evaluation of changes in the cognition of urban structure with presentation of complex numerical values. Research included the following parts: historical urban development analysis of heritage territory, current state analysis, investigation and modelling of territory spatial structure genotypic changes. The results of the presentation demonstrate the limitations and subjectivity of the present system of description of valuable features of the objects of immovable cultural heritage and present the possible way for the improvement of the situation.
38
Sulekan, Ayuna, and Shariffah Suhaila Syed Jamaludin. "Review on Geographically Weighted Regression (GWR) approach in spatial analysis." Malaysian Journal of Fundamental and Applied Sciences 16, no. 2 (April 15, 2020): 173–77. http://dx.doi.org/10.11113/mjfas.v16n2.1387.
Full textAbstract:
In spatial analysis, it is important to identify the nature of the relationship that exists between variables. Normally, it is done by estimating parameters with observations which taken from different spatial units that across a study area where parameters are assumed to be constant across space. However, this is not so as the spatial non-stationarity is a condition in which a simple model cannot explain the relationship between some sets of variables. The nature of the model must alter over space to reflect the structure within the data. Non-stationarity means that the relationship between variables under study varies from one location to another depending on physical factors of the environment that are spatially autocorrelated. Geographically Weighted Regression (GWR) is a technique in which it applied to capture the variation by calibrating a multiple regression model, which allows different relationships to exist at different points in space. A robust algorithm has been successfully used in spatial analysis. GWR can theoretically integrate geographical location, altitude, and other factors for spatial analysis estimations, and reflects the non-stationary spatial relationship between these variables. The main goal of this study is to review the potential of the GWR in modelling the spatial relationship between variables either dependent or independent and its used as the spatial prediction models. Based on the application of GWR such as house property indicates that GWR is the best model in estimating the parameters. Hence, from the GWR model, the significance of the variation can also be tested
39
Maulit, A., A. S. Tlebaldinova, A. B. Nugumanova, and Ye M. Baiburin. "Computer Modelling of Temporal Networks for Bike Sharing Usage Patterns Analysis." Izvestiya of Altai State University, no. 4(114) (September 9, 2020): 102–7. http://dx.doi.org/10.14258/izvasu(2020)4-16.
Full textAbstract:
This paper presents the results of analyzing the time load of stations in bike-sharing systems using temporal networks. Temporal networks have many applications in the study of the behavior of complex dynamic systems that have a network structure. In particular, they can be used to analyze and predict many dynamic indicators of transport networks, for example, such as the intensity of transport and passenger flows, traffic congestion, capacity of transport nodes, turnover of vehicles, etc. In this work, the indicators of the centrality of stations and clusters of a bike-sharing network are estimated using temporal networks. Based on the obtained estimates, visual models (Heat maps and Time Series) are constructed to demonstrate the spatial and temporal features of the bike network in a clear and compact form. The station centralities are estimated on the basis of the betweenness measure, and the cluster centralities are estimated on the basis of the Freeman centralization. Experiments confirming the applicability of the built models are conducted using open data from the CitiBike New York system for April 2019. They demonstrated the presence of daily and monthly patterns among both individual stations and more large station clusters.
40
Pantousa, Daphne, and Euripidis Mistakidis. "Interface modelling between CFD and FEM analysis: the dual-layer post-processing model." Engineering Computations 34, no. 4 (June 12, 2017): 1166–90. http://dx.doi.org/10.1108/ec-06-2015-0146.
Full textAbstract:
Purpose The primary purpose of this paper is the development of a fire–structure interface (FSI) model, which is referred in this study as a simplified “dual-layer” model. It is oriented for design purposes, in the cases where fire-compartments exceed the “regular” dimensions, as they are defined by the guidelines of the codes (EN 1991-1-2). Design/methodology/approach The model can be used at the post-processing stage of computational fluid dynamics (CFD) analysis and it is based on the gas-temperature field (spatial and temporal) of the fire-compartment. To use the “dual-layer” model, first the gas-temperature (discrete) function along the height of the fire-compartment, at discrete plan–view points should be determined through the output of the CFD analysis. The model “compresses” the point data to (spatial) virtual zones, which are divided into two layers (with respect to the height of the fire-compartment) of uniform temperature: the upper (hot) layer and the lower (cold) layer. Findings The model calculates the temporal evolution of the gas-temperature in the fire compartment in every virtual zone which is divided in two layers (hot and cold layer). Originality/value The main advantage of this methodology is that actually only three different variables (height of interface upper-layer temperature and lower-layer temperature) are exported during the post-processing stage of the CFD analysis, for every virtual zone. Next, the gas-temperature can be used for the determination of the temperature profile of structural members using simple models that are proposed in EN 1993-1-2.
41
Samson, Grace L., Joan Lu, and Aminat A. Showole. "Mining Complex Spatial Patterns: Issues and Techniques." Journal of Information & Knowledge Management 13, no. 02 (June 2014): 1450019. http://dx.doi.org/10.1142/s0219649214500191.
Full textAbstract:
Spatial data mining is the quantitative study of phenomena that are located in space. This paper investigates methods of mining patterns of a complex spatial data set (which generally describes any kind of data where the location in space of object holds importance). We based this research on the analysis of some spatial characteristics of certain objects. We began with describing the spatial pattern of events or objects with respect to their attributes; we looked at how to describe the spatial nature/characteristics of entities in an environment with respect to their spatial and non-spatial attributes. We also looked at modelling (predictive modelling/knowledge management of complex spatial systems), querying and implementing a complex spatial database (using data structure and algorithms). Critically speaking, the presence of spatial auto-correlation and the fact that continuous data types are always present in spatial data makes it important to create methods, tools and algorithms to mine spatial patterns in a complex spatial data set. This work is particularly useful to researchers in the field of data mining as it contributes a whole lot of knowledge to different application areas of data mining especially spatial data mining. It can also be useful in teaching and likewise for other study purposes.
42
SCHEUERER, M., R. SCHABACK, and M. SCHLATHER. "Interpolation of spatial data – A stochastic or a deterministic problem?" European Journal of Applied Mathematics 24, no. 4 (February 7, 2013): 601–29. http://dx.doi.org/10.1017/s0956792513000016.
Full textAbstract:
Interpolation of spatial data is a very general mathematical problem with various applications. In geostatistics, it is assumed that the underlying structure of the data is a stochastic process which leads to an interpolation procedure known as kriging. This method is mathematically equivalent to kernel interpolation, a method used in numerical analysis for the same problem, but derived under completely different modelling assumptions. In this paper we present the two approaches and discuss their modelling assumptions, notions of optimality and different concepts to quantify the interpolation accuracy. Their relation is much closer than has been appreciated so far, and even results on convergence rates of kernel interpolants can be translated to the geostatistical framework. We sketch different answers obtained in the two fields concerning the issue of kernel misspecification, present some methods for kernel selection and discuss the scope of these methods with a data example from the computer experiments literature.
43
Okojie, J. A., A. E. Effiom, E. N. Tawiah, and I. J. Akpejiori. "COMPUTATIONAL TIME MODELLING FOR TREE CROWN EXTRACTION FROM HIGH RESOLUTION IMAGERY USING GEOGRAPHIC OBJECT-BASED IMAGE ANALYSIS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W13 (June 4, 2019): 483–88. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w13-483-2019.
Full textAbstract:
<p><strong>Abstract.</strong> Image segmentation, unlike most conventional approaches, assesses image pixel information in relation to image contextual information to extract congruent image objects. A comprehensive review of literature during the research conceptualization phase revealed that while a lot of work has been done into the optimization of the segmentation computational time, there was a conspicuous research gap in the area of computational time modelling and pre-analytical projections.</p><p>The focus of this research was, therefore, to model the computational time requirements of segmentation as a function of variability in image spatial resolutions and pixel counts. The employed methodology integrated structure from motion (SFM), segmentation, and regression modelling into a multiphase workflow to process UAV-acquired imagery into an orthomosaic, which underwent segmentation at multiple resolutions. The segmentation computational time was regressed against the image pixel count and spatial resolution.</p><p>The results showed that the image pixel count was the main determinant of the computational time, expressing a statistically strong linear relationship. However, when the regressors were tested individually, the spatial resolution showed an exponential relationship with computational time which, however, exhibited saturation. It can be inferred that image spatial resolution is not the key determinant of segmentation computational time but the pixel count of the image.</p><p>This research recommends the adoption of statistically viable models to thoroughly assess computational time requirements for image segmentation and a pre-analytics estimation of the time requirements such that image quality &ndash; image processing time adjustments can be made before rather than after analyses have commenced.</p>
44
Colaço, Rui, and João de Abreu e Silva. "Commercial Classification and Location Modelling: Integrating Different Perspectives on Commercial Location and Structure." Land 10, no. 6 (May 28, 2021): 567. http://dx.doi.org/10.3390/land10060567.
Full textAbstract:
Commercial classification is essential to describe and compare the spatial patterns of commercial activity. Most classification systems consider a large set of dimensions that include detailed features such as store ownership or development type. Since new business models are continually being developed, the need to revise classification systems is constant. This makes generalisation hard, thus hindering the comparison of commercial structures in different places and periods. Recent studies have focused on cluster analysis and a smaller number of variables to gain insights into commercial structures, directly addressing this issue. Systematic bottom-up classification generates comparable structures, which is essential to contrast policy results in different situations. Furthermore, since form or accessibility are usually considered in classifications, cluster membership is precluded from most retail location models, often relying on the latter as an explanatory variable. Hence, a new classification system is proposed, based on cluster analysis (k-means) and a minimal set of variables: density, diversity, and clustering. This classification was implemented in 1995, 2002, and 2010 in Lisbon. Cross-sectional analysis of the commercial structures shows the system accurately describes commercial location and change, suggesting it can be generalised as a classification system. Since the minimal dataset also allows for cluster membership to be used on location models, the relationship between commercial classification and location modelling could be strengthened, reinforcing the role of commercial studies in urban planning and policymaking.
45
Nagovitsyna, Ekaterina S., Vassily A. Poddubny, Alexander A. Karasev, Dmitry M. Kabanov, Olga R. Sidorova, and Alexander S. Maslovsky. "Assessment of the Spatial Structure of Black Carbon Concentrations in the Near-Surface Arctic Atmosphere." Atmosphere 14, no. 1 (January 8, 2023): 139. http://dx.doi.org/10.3390/atmos14010139.
Full textAbstract:
The results of the research are numerical estimates of the average fields of black carbon mass concentration in the surface layer of the atmosphere of the Arctic region obtained using the numeric technology referred to as fluid location of the atmosphere (FLA). The modelling has been based on measurements of the black carbon concentrations in the near-surface atmosphere obtained during the two cruises of the Professor Multanovskiy (28 July–7 September 2019) and Akademik Mstislav Keldysh (31 July–24 August 2020) research vessels. These measurements have been supplemented by measurements at stationary monitoring points located on the Spitsbergen and the Severnaya Zemlya archipelagoes. The simulation in the summertime demonstrates that areas of increased black carbon concentrations were observed over Northern Europe and, in 2019, also over the Laptev Sea basin. The obtained spatial distribution of mass concentrations of black carbon qualitatively agreed with the same data derived from the second Modern-Era Retrospective analysis for Research and Applications (MERRA-2) but showed quantitative differences. The average values of mass concentrations of black carbon in the modelling zones are as follows: 85.3 ng/m3 (2019) and 53.6 ng/m3 (2020) for fields reconstructed by the FLA technology; and 261.69 ng/m3 (2019) and 131.8 ng/m3 (2020) for the MERRA-2 data.
46
Feng, Jia, Xiamiao Li, Baohua Mao, Qi Xu, and Yun Bai. "Weighted Complex Network Analysis of the Different Patterns of Metro Traffic Flows on Weekday and Weekend." Discrete Dynamics in Nature and Society 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/9865230.
Full textAbstract:
We present a multilayer model to characterize the weekday and weekend patterns in terms of the spatiotemporal flow size distributions in subway networks, based on trip data and operation timetables obtained from the Beijing Subway System. We also investigate the disparity of incoming and outgoing flows at a given station to describe the different spatial structure performance between transfer and nontransfer stations. In addition, we describe the essential interactions between PFN and TFN by defining an indicator, real load. By comparing with the two patterns on weekday and weekend, we found that the substantial trends have roughly the same form, with noticeable lower sizes of flows on weekend ascribed to the essential characteristics of travel demand.
47
Kondor, Dániel, Sebastian Grauwin, Zsófia Kallus, István Gódor, Stanislav Sobolevsky, and Carlo Ratti. "Prediction limits of mobile phone activity modelling." Royal Society Open Science 4, no. 2 (February 2017): 160900. http://dx.doi.org/10.1098/rsos.160900.
Full textAbstract:
Thanks to their widespread usage, mobile devices have become one of the main sensors of human behaviour and digital traces left behind can be used as a proxy to study urban environments. Exploring the nature of the spatio-temporal patterns of mobile phone activity could thus be a crucial step towards understanding the full spectrum of human activities. Using 10 months of mobile phone records from Greater London resolved in both space and time, we investigate the regularity of human telecommunication activity on urban scales. We evaluate several options for decomposing activity timelines into typical and residual patterns, accounting for the strong periodic and seasonal components. We carry out our analysis on various spatial scales, showing that regularity increases as we look at aggregated activity in larger spatial units with more activity in them. We examine the statistical properties of the residuals and show that it can be explained by noise and specific outliers. Also, we look at sources of deviations from the general trends, which we find to be explainable based on knowledge of the city structure and places of attractions. We show examples how some of the outliers can be related to external factors such as specific social events.
48
Perpiña Castillo, Carolina, Eloína Coll Aliaga, Carlo Lavalle, and José Carlos Martínez Llario. "An Assessment and Spatial Modelling of Agricultural Land Abandonment in Spain (2015–2030)." Sustainability 12, no. 2 (January 11, 2020): 560. http://dx.doi.org/10.3390/su12020560.
Full textAbstract:
This article presents a study based on the outputs from the LUISA Territorial modelling platform (Joint Research Centre of the European Commission) focused on regional and local future projections of land abandonment between 2015 and 2030. Spain is taken as representative of one of the countries highly affected by agricultural land abandonment in the European Union. The most relevant factors driving land abandonment (biophysical, agroeconomics, farm structure and demographic) are described and mapped. Results from the analysis reveal that the Galicia region, northern Spain (Asturias, Cantabria, Gipuzkoa, Bizkaia), north-eastern Spain (Aragón region), central Pyrenees/Ebro basin (Huesca, Navarra, Lleida) and south-eastern Spain (Murcia, Almería, Alicante, Málaga) are expected to undergo important abandonment processes. The study also concludes that land abandonment within mountainous, high nature value farmland and Natura 2000 areas is lower compared to the outside area without conservation and protection measures.
49
Sehnert, C., S. Huang, and K. E. Lindenschmidt. "Quantifying structural uncertainty due to discretisation resolution and dimensionality in a hydrodynamic polder model." Journal of Hydroinformatics 11, no. 1 (January 1, 2009): 19–30. http://dx.doi.org/10.2166/hydro.2009.038b.
Full textAbstract:
In flood modelling, the structure of conceptual models may have a large influence on the simulation results. Hence, the focus of this paper is on the structural uncertainty in hydrodynamic flood modelling systems. Three different conceptual models with an increasing order of complexity of the spatial discretisation of the flow through a polder system were compared in order to investigate the effect of spatial resolution and dimensionality on flood modelling. The hydrodynamic 1D model DYNHYD was used as a basis for the simulations. The model was extended to incorporate a quasi-2D approach and a Monte Carlo analysis was used to show the effect of structural uncertainty on the resulting flow characteristics of the diverted flood waters. Two flood events of the River Elbe were used to calibrate and test the model. The results of the velocity fields indicate that the simplest 1D model revealed more predictive uncertainty than the other two more complex models. The differences in model structure does not cause large differences in the capping of the peak discharges, but may substantially influence the results of subsequent modelling of sediment and contaminant transport.
50
SOARES, LUCAS, ERNAN RUSTIADI, and SRI MULATSIH. "Analisis Disparitas dan Interaksi Spasial di Timor-Leste." Journal of Regional and Rural Development Planning 1, no. 1 (February 28, 2017): 74. http://dx.doi.org/10.29244/jp2wd.2017.1.1.74-86.
Full textAbstract:
Spatial planning is a tool to achieve braden goals of development. To support economic development in Timor Leste, it needs an optimal spatial structure planning that supports connectivities between districts through infrastructures network. This research aimed to analyze and explain disparities, interaction and optimal regional spatial structure using variables of infrastructures and public facilities on national and regional/districts/subnational activities center. This research used Scalogram and gravitation modelling analysis. The results showed that there is a high disparity level between districts in Timor-Leste that caused by the lack of public facilities and lack of access to public services. Moreover, the spatial structure interaction between districts are very weak. To cope with those problems, this research suggested the formulation of one national activity center located in the north (Dili) and three Regional (subnational) Activity Center (RAC) located at Ermera in the west, Baucau in the east and Manufahi in the south of Timor-Leste