23 research outputs found

    Management of spatial data for visualization on mobile devices

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    Vector-based mapping is emerging as a preferred format in Location-based Services(LBS), because it can deliver an up-to-date and interactive map visualization. The Progressive Transmission(PT) technique has been developed to enable the ecient transmission of vector data over the internet by delivering various incremental levels of detail(LoD). However, it is still challenging to apply this technique in a mobile context due to many inherent limitations of mobile devices, such as small screen size, slow processors and limited memory. Taking account of these limitations, PT has been extended by developing a framework of ecient data management for the visualization of spatial data on mobile devices. A data generalization framework is proposed and implemented in a software application. This application can signicantly reduce the volume of data for transmission and enable quick access to a simplied version of data while preserving appropriate visualization quality. Using volunteered geographic information as a case-study, the framework shows exibility in delivering up-to-date spatial information from dynamic data sources. Three models of PT are designed and implemented to transmit the additional LoD renements: a full scale PT as an inverse of generalisation, a viewdependent PT, and a heuristic optimised view-dependent PT. These models are evaluated with user trials and application examples. The heuristic optimised view-dependent PT has shown a signicant enhancement over the traditional PT in terms of bandwidth-saving and smoothness of transitions. A parallel data management strategy associated with three corresponding algorithms has been developed to handle LoD spatial data on mobile clients. This strategy enables the map rendering to be performed in parallel with a process which retrieves the data for the next map location the user will require. A viewdependent approach has been integrated to monitor the volume of each LoD for visible area. The demonstration of a exible rendering style shows its potential use in visualizing dynamic geoprocessed data. Future work may extend this to integrate topological constraints and semantic constraints for enhancing the vector map visualization

    Continuous and Adaptive Cartographic Generalization of River Networks

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    The focus of our research is on a new automated smoothing method and its applications. Traditionally, the application of a smoothing method to a collection of polylines produces a new smoothed dataset. Although the new dataset was derived from the original dataset, it is stored independently. Since many smoothing methods are slow to execute, this is a valid trade-off. However, this greatly increases the data storage requirements for each new smoothing. A consequence of this approach is that interactive map systems can only offer maps at a discrete set of scales. It is desirable to have a fast enough method that would support the reuse of a single base dataset for on-the-fly smoothing for the production of maps at any scale.We were able to create a framework for the automated smoothing of river networks based on the following major contributions:– A wavelet--based method for polyline smoothing and endpoint preservation– Inverse Mirror Periodic (IMP) representation of functions and signals, and dimensional wavelets– Smoothing of features that does not change abruptly between scales– Features are pruned in a continuous manner with respect to scale– River network connectedness is maintained for all scales– Reuse of a base geographic dataset for all scales– Design and implementation of an interactive map viewer for linear hydrographic features that renders in subsecond timeWe have created an interactive map that can smoothly zoom to any region. Numerical experiments show that our wavelet-based method produces cartographically appropriate smoothing for tributaries. The system is implemented to view hydrographic data, such as the USGS National Hydrography Dataset (NHD). The map demonstrates that a wavelet--based approach is well suited for basic generalization operations. It provides smoothing and pruning that is continuously dependent on map scale

    Magnetic Fields and Cancer: Epidemiology, Cellular Biology, and Theranostics

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    Humans are exposed to a complex mix of man-made electric and magnetic fields (MFs) at many different frequencies, at home and at work. Epidemiological studies indicate that there is a positive relationship between residential/domestic and occupational exposure to extremely low frequency electromagnetic fields and some types of cancer, although some other studies indicate no relationship. In this review, after an introduction on the MF definition and a description of natural/anthropogenic sources, the epidemiology of residential/domestic and occupational exposure to MFs and cancer is reviewed, with reference to leukemia, brain, and breast cancer. The in vivo and in vitro effects of MFs on cancer are reviewed considering both human and animal cells, with particular reference to the involvement of reactive oxygen species (ROS). MF application on cancer diagnostic and therapy (theranostic) are also reviewed by describing the use of different magnetic resonance imaging (MRI) applications for the detection of several cancers. Finally, the use of magnetic nanoparticles is described in terms of treatment of cancer by nanomedical applications for the precise delivery of anticancer drugs, nanosurgery by magnetomechanic methods, and selective killing of cancer cells by magnetic hyperthermia. The supplementary tables provide quantitative data and methodologies in epidemiological and cell biology studies. Although scientists do not generally agree that there is a cause-effect relationship between exposure to MF and cancer, MFs might not be the direct cause of cancer but may contribute to produce ROS and generate oxidative stress, which could trigger or enhance the expression of oncogenes

    Revised Full Proposal

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    Paths of inequality: migration, inter-relationships and the gender division of labour

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    International migration and modern means of transportation and communication make it easier for people to meet and form relationships across borders and national origins. The growth of academic interest in marriage migration and family migration has led to greater attention being paid to (im)migrant families and couples and the formation of mixed unions between migrants and natives. While migrant women were long overlooked in migration studies, they are now established subjects of research. However, the (re)production of gender inequalities through migration remains neglected, especially in quantitative research. This PhD research seeks to address this gap through a comparative study of migrants’ couple formation and gendered dynamics in France and the United Kingdom. Starting with a critical, historical and political examination of survey data on mixedness and migration in both countries, it investigates the difficulty and the necessity of considering migration as a gendered experience of mobility. That is, not simply who migrates or how many migrate, but how they migrate, with whom and at what point in their life. Using Understanding Society and Trajectoires et Origines data, this PhD models and weighs the complex interlocking of migration in the life course through sequences of migration and family formation, which it ultimately connects to patterns of paid and unpaid labour division between partnered women and men. Through sequence analysis, it constructs a typology of union-migration trajectories which reveals the gendered paths of migration and mixedness. These trajectories, in turn, help make sense of why, for migrant women, both migration and mixing can be associated with heightened gender-specialisation of housework and care work on the one hand, and paid work on the other. By presenting an analysis which emphasizes trajectories and intermarriage (rather than profiles and endogamous unions), this PhD offers a complex analysis of how gender relations frame migration and how migration re-defines but often entrenches gender inequalities

    Plant Biodiversity and Genetic Resources

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    The papers included in this Special Issue address a variety of important aspects of plant biodiversity and genetic resources, including definitions, descriptions, and illustrations of different components and their value for food and nutrition security, breeding, and environmental services. Furthermore, comprehensive information is provided regarding conservation approaches and techniques for plant genetic resources, policy aspects, and results of biological, genetic, morphological, economic, social, and breeding-related research activities. The complexity and vulnerability of (plant) biodiversity and its inherent genetic resources, as an integral part of the contextual ecosystem and the human web of life, are clearly demonstrated in this Special Issue, and for several encountered problems and constraints, possible approaches or solutions are presented to overcome these
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