International Review on Computers and Software 5 (3), 2010
Poorazizi, E., Alesheikh, A. A., and Amini, M.
“Distributing and sharing air pollution information through the Web provides flexible and real time data access, and assists people to discover and use such information. It can also assist authorities and decision makers to collaborate in preventing, controlling, and responding to air pollution and health related issues.
“Virtual globe software systems such as Google Earth are growing rapidly in popularity as a way to visualize and share environmental data. They are changing the way in which scientists and the general public interact with geospatial data in a virtual environment. The appeal of Google Earth provides unprecedented opportunities for public access to data and collaborative engagement over the Web.
“However, while Google Earth provides a number of features to facilitate geospatial data access and visualization, there are currently no readily available tools to support GIS (Geographic Information System) modeling and analysis. Web services provide ubiquitous discovery, access, processing, and visualizing spatial data. In this paper, based on Web services technology, a solution is presented to provide the possibility of performing arbitrary spatial analysis and enhance the functionality of Google Earth. Furthermore, the integration of information provided by such services into Google Earth increases the availability of information for most general users.
“In this research, we have developed an OGC (Open Geospatial Consortium) Web Processing Service to provide on-demand air pollution maps and disseminate real-time air quality information using Web services technology. We also investigate the technological requirements of virtual globes towards web based process integration and propose an approach to integrate processing tasks into such applications. The applicability of the approach is demonstrated by an environmental monitoring scenario.
“This paper explains that the using of Web services technology and OGC framework provide easy access to geospatial data and processing services over the Internet in interoperable manner. It is also concluded that coupling the geospatial Web services with virtual globe applications is an efficient solution to publish environmental data.”
Spatio-Temporal Constraints on Social Networks Workshop, University of California, Santa Barbara, Center for Spatial Studies, 13-14 December 2010
“Homophily as Constraint and Opportunity
“Space–time homophily suggests that many activities are local, in some sense. Localness is a type of constraint that is susceptible of exploitation. In this circumstance techniques such as multidimensional scaling can often yield locational coordinates. It may then be possible to analyze flows of information, or the movement of people, etc, using the space-time coordinates that describe where these events are positioned in this homophilyic environment. The localness of such events implies the possibility of estimating partial derivatives in time and space. If this is valid then a further suggestion is that one can interpret these as gradients, i.e., space-time vectors. An interpolation in space-time of individual vectors can then be performed to obtain a quasi-continuous vector field. The vector field, if it is a gradient field, will be curl free, a situation that should be tested. Integration, in the mathematical sense, of the vector field can then give one a scalar potential. This potential is of course determined only up to a constant of integration. And the potential should be that its gradient coincides with the original vectors; an iteration may be necessary to obtain this result. The final potential forms a compact description of the event situation.
“Numerous indices and statistics have been developed in conjunction with two-way arrays. At the same time such data tables are increasingly available at several instances in time. One such example are from-to tables of geographic movement such as the several decades (1935–1940, 1949–1950, 1955–1960, 1965–1970, 1975–1980, 1985–2090, 1990–2000) of U.S. Census Bureau state to state migration tables. Another example are the regional input/output tables over time. I suspect that network indices have been developed or implemented for the analysis of such sequences, but I am not familiar with any. This needs to be looked at.”
BMC Veterinary Research 2010, Published 30 December 2010
Zvonimir Poljak, Catherine E Dewey, Thomas Rosendal, Robert M Friendship, Beth Young, and Olaf Berke
“Background: The systemic form of porcine circovirus associated disease (PCVAD), also known as postweaning multisystemic wasting syndrome (PMWS) was initially detected in the early 1990s. Starting in 2004, the Canadian swine industry experienced considerable losses due to PCVAD, concurrent with a shift in genotype of porcine circovirus type 2 (PCV2). Objectives of the current study were to explore spatial characteristics of self-reported PCVAD distribution in Ontario between 2004 and 2008, and to investigate the existence and nature of local spread.
“Results: The study included 278 swine herds from a large disease-monitoring project that included porcine reproductive and respiratory syndrome (PRRS) virus-positive herds identified by the diagnostic laboratory, and PRRS virus-negative herds directly from the target population. Herds were included if they had growing pigs present on-site and available geographical coordinates for the sampling site. Furthermore, herds were defined as PCVAD-positive if a producer reported an outbreak of circovirus associated disease, or as PCVAD-negative if no outbreak was noted. Spatial trend was investigated using generalized additive models and time to PCVAD outbreak in a herd using Cox’s proportional hazard model; spatial and spatio-temporal clustering was explored using K-functions; and location of most likely spatial and spatio-temporal clusters was investigated using scan statistics. Over the study period, the risk of reporting a PCVAD-positive herd tended to be higher in the eastern part of the province after adjustment for herd PRRS status (P = 0.05). This was partly confirmed for spread (Partial P < 0.01). Local spread also appeared to exist, as suggested by the tentative (P = 0.06) existence of spatio-temporal clustering of PCVAD and detection of a spatio-temporal cluster (P = 0.04).
“Conclusions: In Ontario, PCVAD has shown a general trend, spreading from east-to-west. We interpret the existence of spatio-temporal clustering as evidence of spatio-temporal aggregation of PCVAD-positive cases above expectations and, together with the existence of spatio-temporal and spatial clusters, as suggestive of apparent local spread of PCVAD. Clustering was detected at small spatial and temporal scales. Other patterns of spread could not be detected; however, survival rates in discrete Ontario zones, as well as a lack of a clear spatial pattern in the most likely spatio-temporal clusters, suggest other between-herd transmission mechanisms.”