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Seung-Hyun Jeong Norman W. Paton Alvaro A. A. Fernandes Tony Griffiths 《Transactions in GIS》2005,9(2):129-156
Many applications capture, or make use of, spatial data that changes over time. This requirement for effective and efficient spatio‐temporal data management has given rise to a range of research activities relating to spatio‐temporal data management. Such work has sought to understand, for example, the requirements of different categories of application, and the modelling facilities that are most effective for these applications. However, at present, there are few systems with fully integrated support for spatio‐temporal data, and thus developers must often construct custom solutions for their applications. Developers of both bespoke solutions and of generic spatio‐temporal platforms will often need to support the fusion of large spatio‐temporal data sets. Supporting such requests in a database setting involves the use of join operations with both spatial and temporal conditions – spatio‐temporal joins. However, there has been little work to date on spatio‐temporal join algorithms or their evaluation. This paper presents an evaluation of several approaches to the implementation of spatio‐temporal joins that build upon widely available indexing techniques. The evaluation explores how several algorithms perform for databases with different spatial and temporal characteristics, with a view to helping developers of generic infrastructures or custom solutions in the selection and development of appropriate spatio‐temporal join strategies. 相似文献
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Bergur Sigfusson Sigurdur R. Gislason Graeme I. Paton 《Journal of Geochemical Exploration》2006,88(1-3):321
Histic Andosol in Western Iceland was studied using laboratory based repacked microcosms conjointly with sampling of field soil solution. The main primary phase of the 205 cm thick soil profile was basaltic glass, allophane content ranged from 2 to 22 wt.% and the soil carbon content ranged from 11 to 42 wt.%. At constant temperature, the dissolution rate of the basaltic glass, and probably allophane and imogolite, was dictated by the aH+3 / aAl3+ activity ratio only, which in turn is governed by the pH, total dissolved Al and the anions capable of complexing Al3+; SO42−, F− and organic anions (DOC). Dissolution rate was slowed down by up to 20% by decreasing undersaturation in the field. Dissolution rate of basaltic glass was stable after an initial flushing event at the beginning of microcosm experiments. Predicted dissolution rates increased up to a factor of 7 and 30 by speciating Al3+ with oxalate in field and microcosms respectively. Speciation with oxalate generally had more effect in shallow horizons than deep horizons. 相似文献
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Traditional approaches to risk communication ignore the emotional, cognitive and social factors that interact to influence the meaning people attribute to hazards and protective actions. The aim of this study was to investigate the emotional and cognitive factors predicting preparedness intention and community’s preparedness for flood hazards. A cross-sectional study was conducted between June and July 2015, in Dire Dawa town, Ethiopia. Using stratified systematic random sampling, a structured questionnaire was administered to individuals aged 18 and over in 660 households. Data were analyzed using structural equation modeling (SEM) (STATA version 13.0). The study participants’ mean age was 34 years, ranging from 18 to 80 (SD?=?12) with equal gender balance. SEM analysis revealed that the total effects of preparedness intention (path coefficient (β)?=?0.202, 95% CI: [0.036, 0.369]), past flood disaster experience (β?=?0.034, 95% CI: [0.008, 0.061]), trust (β?=?0.100, 95% CI: [0.059, 0.142]), anxiety (β?=?0.026, 95% CI: [0.018, 0.034), positive outcome expectancy (β?=???0.139, 95% CI: [??0.253, ??0.026]), negative outcome expectancy (β?=?0.105, 95% CI: [0.062, 0.149]), perceived flood likelihood (β?=?0.049, 95% CI: [0.012, 0.086]) and consequence (β?=???0.040, 95% CI: [??0.077, ??0.003]) on community preparedness for flood hazards were statistically significant. The main implication of these findings is that people affected by hazard events in the past experience more anxiety and are more likely to participate in community preparedness activities than those who were not affected. 相似文献
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Predicting community earthquake preparedness: a cross-cultural comparison of Japan and New Zealand 总被引：1，自引：1，他引：0
This paper reports on a study investigating cross-cultural equivalence in predictors of earthquake preparedness. Data were
collected from Napier (New Zealand) and Kyoto (Japan). These locations were selected because they face comparable levels of
seismic risk but differ with respect to their cultural characteristics. This mix of hazard similarity and cultural differences
provided an opportunity to assess the degree of cross-cultural equivalence in predictors of earthquake preparedness. Cross-cultural
equivalence was examined by assessing the degree to which individual hazard beliefs (outcome expectancies) and social characteristics
(community participation, collective efficacy, empowerment, trust) could explain levels of hazard preparedness in each location.
Structural equation modelling analyses revealed similarity in the pattern of relationships between predictor variables and
intention prepare in the Napier and Kyoto data. It is argued that this provides support for the existence of some universal,
cross-cultural equivalence in how hazard beliefs and social characteristics interact to predict the degree to which people
adopt earthquake preparedness measures. Differences between the data sets are discussed in the context of the fundamental
cultural differences between Japan and New Zealand. The theoretical and practical implications of the findings are discussed. 相似文献
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A model of household preparedness for earthquakes: how individuals make meaning of earthquake information and how this influences preparedness 总被引：4，自引：3，他引：1
One way to reduce the risk from earthquakes is for individuals to undertake preparations for earthquakes at home. Common preparation measures include gathering together survival items, undertaking mitigation actions, developing a household emergency plan, gaining survival skills or participating in wider social preparedness actions. While current earthquake education programmes advocate that people undertake a variety of these activities, actual household preparedness remains at modest levels. Effective earthquake education is inhibited by an incomplete understanding of how the preparedness process works. Previous research has focused on understanding the influence individual cognitive processes have on the earthquake preparedness process but has been limited in identifying other influences posed by the wider social contextual environment. This project used a symbolic interactionism perspective to explore the earthquake preparedness process through a series of qualitative interviews with householders in three New Zealand urban locations. It investigated earthquake information that individuals are exposed to, how people make meaning of this information and how this relates to undertaking actual preparedness measures. During the study, the relative influence of cognitive, emotive and societal factors on the preparedness process was explored and the interactions between these identified. A model of the preparedness process based on the interviews was developed and is presented in this paper. 相似文献
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D.?JohnstonEmail author D.?Paton G.?L.?Crawford K.?Ronan B.?Houghton P.?Bürgelt 《Natural Hazards》2005,35(1):173-184
A survey of over 300 residents and visitors (non-residents) perceptions of tsunami hazards was carried out along the west coast of Washington State during August and September 2001. The study quantified respondents preparedness to deal with tsunami hazards. Despite success in disseminating hazard information, levels of preparedness were recorded at low to moderate levels. This finding is discussed in regard to the way in which people interpret hazard information and its implications for the process of adjustment adoption or preparedness. These data are also used to define strategies for enhancing preparedness. Strategies involve maintaining and enhancing hazard knowledge and risk perception, promoting the development of preparatory intentions, and facilitating the conversion of these intentions into sustained preparedness. A second phase of work began in February 2003, consisting of a series of focus groups which examined beliefs regarding preparedness and warnings, and a school survey. Preliminary findings of this work are presented. 相似文献
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An evaluation of acid deposition on cation leaching and weathering rates of an Andosol and a Cambisol 总被引：1，自引：0，他引：1
An evaluation of the response of an Andosol and a Cambisol to acid deposition and weathering rates was studied by using a controlled laboratory leaching experiment. Both soils where derived from mafic parent material, a Histic Andosol from Western Iceland and a Cambisol from North East Scotland. De-ionized water and water acidified with H2SO4 (pH 3) was leached through reconstructed soil columns to simulate 34 years of precipitation.Acidic input increased cation leaching and weathering rates in both soil types and reduced pH levels. The Andosol proved generally to have higher weathering rates, leaching potential, ion exchange and acid-buffering capacity as well as maintaining a relatively steady pH despite intense acidic input. This was due to differences in parent material and mineral composition. The Andosol was developed from basaltic volcanic tephra, which had higher dissolution rates due to its amorphous mineral structures. The Cambisol was developed from gabbro with more stable mineral structures. 相似文献