Geosocial gauge: a system prototype for knowledge discovery from social media     

Arie Croitoru  Andrew Crooks  Jacek Radzikowski  Anthony Stefanidis 《International journal of geographical information science》2013,27(12):2483-2508

The remarkable success of online social media sites marks a shift in the way people connect and share information. Much of this information now contains some form of geographical content because of the proliferation of location-aware devices, thus fostering the emergence of geosocial media – a new type of user-generated geospatial information. Through geosocial media we are able, for the first time, to observe human activities in scales and resolutions that were so far unavailable. Furthermore, the wide spectrum of social media data and service types provides a multitude of perspectives on real-world activities and happenings, thus opening new frontiers in geosocial knowledge discovery. However, gleaning knowledge from geosocial media is a challenging task, as they tend to be unstructured and thematically diverse. To address these challenges, this article presents a system prototype for harvesting, processing, modeling, and integrating heterogeneous social media feeds towards the generation of geosocial knowledge. Our article addresses primarily two key components of this system prototype: a novel data model for heterogeneous social media feeds and a corresponding general system architecture. We present these key components and demonstrate their implementation in our system prototype, GeoSocial Gauge.  相似文献   

Crafting Regional Cultural Production: emergence,crisis and consolidation in the Gold Coast surfboard industry   总被引：1，自引：0，他引：1  

Andrew Warren 《The Australian geographer》2013,44(4):365-381

Surfboard-making is concentrated in regions with vibrant surfing subcultures, suitable waves and sufficient expertise in crafting boards, by hand, to suit prevailing coastal conditions. This article charts the rise of the Gold Coast as Australia's most concentrated cluster of surfboard-making, from its origins as do-it-yourself craft in backyards and sheds, to professional, export-oriented industry. Out of highly informal, subcultural origins, a regional cluster emerged in the 1960s, fuelled by the growth of surfing, tourism and suburban development, and by the needs of surfers for customised boards that suit their body size, surfing style and local wave conditions. What transpired was a vernacular form of coastal creative industry combining craft skills, subcultural knowledge and design flair. Nevertheless, a mix of factors, including automation, increased competition from cheap imports, increasingly aggressive retail trade, and mistrust among board-makers, has threatened viability. Some workshops overextended into export production, marketing and automation, and consequently suffered from exposure to risk (as well as a commensurate decline in regional tourism). Others survived, and in some ways turned full circle: those small workshops continuing to service local markets, within their means, were most able to ride out the industry's turbulent times. Small-scale cultural production persists despite the volatility of the larger brands, geared instead around loyal customers who want hand-crafted boards made by shapers who they know and trust.  相似文献   

Heterogeneous redox conditions, arsenic mobility, and groundwater flow in a fractured-rock aquifer near a waste repository site in New Hampshire, USA     

Philip T. Harte  Joseph D. Ayotte  Andrew Hoffman  Kinga M. Révész  Marcel Belaval  Steven Lamb  J. K. B?hlke 《Hydrogeology Journal》2012,20(6):1189-1201

Anthropogenic sources of carbon from landfill or waste leachate can promote reductive dissolution of in situ arsenic (As) and enhance the mobility of As in groundwater. Groundwater from residential-supply wells in a fractured crystalline-rock aquifer adjacent to a Superfund site in Raymond, New Hampshire, USA, showed evidence of locally enhanced As mobilization in relatively reducing (mixed oxic-anoxic to anoxic) conditions as determined by redox classification and other lines of evidence. Redox classification was determined from geochemical indicators based on threshold concentrations of dissolved oxygen (DO), nitrate (NO ₃ ^– ), iron (Fe²⁺), manganese (Mn²⁺), and sulfate (SO ₄ ^2– ). Redox conditions were evaluated also based on methane (CH₄), excess nitrogen gas (N₂) from denitrification, the oxidation state of dissolved As speciation (As(III) and As(V)), and several stable isotope ratios. Samples from the residential-supply wells primarily exhibit mixed redox conditions, as most have long open boreholes (typically 50–100?m) that receive water from multiple discrete fractures with contrasting groundwater chemistry and redox conditions. The methods employed in this study can be used at other sites to gauge redox conditions and the potential for As mobilization in complex fractured crystalline-rock aquifers where multiple lines of evidence are likely needed to understand As occurrence, mobility, and transport.  相似文献   

Mineralogical, stable isotope, and fluid inclusion studies of spatially related porphyry Cu and epithermal Au-Te mineralization, Fakos Peninsula, Limnos Island, Greece     

Andrew P. Fornadel  Panagiotis Ch. Voudouris  Paul G. Spry  Vasilios Melfos 《Mineralogy and Petrology》2012,105(1-2):85-111

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Evaluation of coastal inundation hazard for present and future climates   总被引：2，自引：1，他引：1  

Andrew J. Condon  Y. Peter Sheng 《Natural Hazards》2012,62(2):345-373

Coastal inundation from hurricane storm surges causes catastrophic damage to lives and property, as evidenced by recent hurricanes including Katrina and Wilma in 2005 and Ike in 2008. Changes in hurricane activity and sea level due to a warming climate, together with growing coastal population, are expected to increase the potential for loss of property and lives. Current inundation hazard maps: Base Flood Elevation maps and Maximum of Maximums are computationally expensive to create in order to fully represent the hurricane climatology, and do not account for climate change. This paper evaluates the coastal inundation hazard in Southwest Florida for present and future climates, using a high resolution storm surge modeling system, CH3D-SSMS, and an optimal storm ensemble with multivariate interpolation, while accounting for climate change. Storm surges associated with the optimal storms are simulated with CH3D-SSMS and the results are used to obtain the response to any storm via interpolation, allowing accurate representation of the hurricane climatology and efficient generation of hazard maps. Incorporating the impact of anticipated climate change on hurricane and sea level, the inundation maps for future climate scenarios are made and affected people and property estimated. The future climate scenarios produce little change to coastal inundation, due likely to the reduction in hurricane frequency, except when extreme sea level rise is included. Calculated coastal inundation due to sea level rise without using a coastal surge model is also determined and shown to significantly overestimate the inundation due to neglect of land dissipation.  相似文献   

Lacustrine records of Holocene flood pulse dynamics in the Upper Paraguay River watershed (Pantanal wetlands,Brazil)     

Michael M. McGlue  Aguinaldo Silva  Hiran Zani  Fabrício A. Corradini  Mauro Parolin  Erin J. Abel  Andrew S. Cohen  Mario L. Assine  Geoffrey S. Ellis  Mark A. Trees  Sidney Kuerten  Frederico dos Santos Gradella  Giliane Gessica Rasbold 《Quaternary Research》2012,78(2):285-294

The Pantanal is the world's largest tropical wetland and a biodiversity hotspot, yet its response to Quaternary environmental change is unclear. To address this problem, sediment cores from shallow lakes connected to the Upper Paraguay River (PR) were analyzed and radiocarbon dated to track changes in sedimentary environments. Stratal relations, detrital particle size, multiple biogeochemical indicators, and sponge spicules suggest fluctuating lake-level lowstand conditions between ~ 11,000 and 5300 cal yr BP, punctuated by sporadic and in some cases erosive flood flows. A hiatus has been recorded from ~ 5300 to 2600 cal yr BP, spurred by confinement of the PR within its channel during an episode of profound regional drought. Sustained PR flooding caused a transgression after ~ 2600 cal yr BP, with lake-level highstand conditions appearing during the Little Ice Age. Holocene PR flood pulse dynamics are best explained by variability in effective precipitation, likely driven by insolation and tropical sea-surface temperature gradients. Our results provide novel support for hypotheses on: (1) stratigraphic discontinuity of floodplain sedimentary archives; (2) late Holocene methane flux from Southern Hemisphere wetlands; and (3) pre-colonial indigenous ceramics traditions in western Brazil.  相似文献   

Harvesting ambient geospatial information from social media feeds   总被引：5，自引：0，他引：5  

Anthony Stefanidis  Andrew Crooks  Jacek Radzikowski 《GeoJournal》2013,78(2):319-338

Social media generated from many individuals is playing a greater role in our daily lives and provides a unique opportunity to gain valuable insight on information flow and social networking within a society. Through data collection and analysis of its content, it supports a greater mapping and understanding of the evolving human landscape. The information disseminated through such media represents a deviation from volunteered geography, in the sense that it is not geographic information per se. Nevertheless, the message often has geographic footprints, for example, in the form of locations from where the tweets originate, or references in their content to geographic entities. We argue that such data conveys ambient geospatial information, capturing for example, people’s references to locations that represent momentary social hotspots. In this paper we address a framework to harvest such ambient geospatial information, and resulting hybrid capabilities to analyze it to support situational awareness as it relates to human activities. We argue that this emergence of ambient geospatial analysis represents a second step in the evolution of geospatial data availability, following on the heels of volunteered geographical information.  相似文献   

Structural and Tectonic Framework of the Qilian Shan-Nan Shan Thrust belt,Northeastern Tibetan Plateau     

Andrew ZUZA  Robin REITH  An YIN  DONG Shuwen  LIU Wencan  ZHANG Yuxiu  WU Chen 《《地质学报》英文版》2013,87(Z1):1-3

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Implementation/optimization of moving least squares response surfaces for approximation of hurricane/storm surge and wave responses     

Alexandros A. Taflanidis  Gaofeng Jia  Andrew B. Kennedy  Jane M. Smith 《Natural Hazards》2013,66(2):955-983

One of the important recent advances in the field of hurricane/storm modelling has been the development of high-fidelity numerical simulation models for reliable and accurate prediction of wave and surge responses. The computational cost associated with these models has simultaneously created an incentive for researchers to investigate surrogate modelling (i.e. metamodeling) and interpolation/regression methodologies to efficiently approximate hurricane/storm responses exploiting existing databases of high-fidelity simulations. Moving least squares (MLS) response surfaces were recently proposed as such an approximation methodology, providing the ability to efficiently describe different responses of interest (such as surge and wave heights) in a large coastal region that may involve thousands of points for which the hurricane impact needs to be estimated. This paper discusses further implementation details and focuses on optimization characteristics of this surrogate modelling approach. The approximation of different response characteristics is considered, and special attention is given to predicting the storm surge for inland locations, for which the possibility of the location remaining dry needs to be additionally addressed. The optimal selection of the basis functions for the response surface and of the parameters of the MLS character of the approximation is discussed in detail, and the impact of the number of high-fidelity simulations informing the surrogate model is also investigated. Different normalizations of the response as well as choices for the objective function for the optimization problem are considered, and their impact on the accuracy of the resultant (under these choices) surrogate model is examined. Details for implementation of the methodology for efficient coastal risk assessment are reviewed, and the influence in the analysis of the model prediction error introduced through the surrogate modelling is discussed. A case study is provided, utilizing a recently developed database of high-fidelity simulations for the Hawaiian Islands.  相似文献   

Bombs behaving badly: unexpected trajectories and cooling of volcanic projectiles     

Lo?c Vanderkluysen  Andrew J. L. Harris  Karim Kelfoun  Costanza Bonadonna  Maurizio Ripepe 《Bulletin of Volcanology》2012,74(8):1849-1858

We collected thermal infrared video of two explosive eruptions at Stromboli in June 2008 and manually traced the trajectories of 95 particles launched during two eruptions. We found that 10–15?% of the analyzed trajectories deviated from predicted curves due to collisions, causing one particle to travel horizontally more than twice as far as expected. Furthermore, we observed an oscillatory cooling behavior for the airborne pyroclasts, with a median period of 0.46?s. Measured cooling was typically much faster than model-predicted cooling with discrepancies of up to 40?% between measured cooling and theoretical modeling. We interpret the measured cooling curves as resulting from the spinning and twisting and tearing of particles during travel: the periodic re-exposing of the hotter core of the pyroclasts to the atmosphere may cause the observed oscillations, and the spinning may accelerate cooling by enhancing convective heat transfer. Current volcanic trajectory and cooling models do not account for projectile collisions, spinning, or tearing and can thus severely underestimate the maximum landing distance and cooling rates of large pyroclasts.  相似文献