Maintaining Quality of Service for Adaptive Mobile Map Clients

Mobile devices must deal with limited and dynamically varying resources, in particular, the network quality of service (QoS). In addition, wireless devices have other constraints such as limited memory, battery power, and physical dimensions. Applications that execute in such environments need to adapt to the dynamic operating conditions in order to preserve an acceptable level of service as close to 100% of the time as possible. Viewing and downloading digital spatial data on mobile devices has become more popular, especially with the availability of location-aware applications that exploit GPS (Global Positioning System) receivers integrated in many of today's mobile devices. Map client applications face many challenges in accessing data across a wireless network. Vector spatial data files tend to be large, and file sizes tend to increase unpredictably depending on the complexity of feature geometry. Due to the limited size of the mobile device display, viewing all the details of the map could cause unreasonable clutter and render the map useless. Even if it is feasible to transmit all the details from a QoS standpoint, this could pose a problem from a usability standpoint. This research effort aims to tackle the issues of QoS and usability on mobile devices through a client-proxy-server model where clients are on mobile devices. The proxy performs two functions. First, it supplies the client with vital data about the status of the system that allows the client to take adaptive decisions aimed at maintaining the QoS. Second, it performs the adaptive actions requested by the client. There are two types of adaptive actions performed by the proxy, activating and deactivating filters. When filters are activated, the amount of data transmitted from the server to the client is reduced. The client may decide to activate one or more filters either to maintain QoS or to limit clutter on the screen and enhance usability. The map client-server application and the proxy were developed in Java (tm), and a number of experiments and real-life scenarios were designed to determine the effectiveness and feasibility of the proposed adaptation model and to evaluate the performance of the proxy

Geo-Information Technology and Its Applications

Geo-information technology has been playing an ever more important role in environmental monitoring, land resource quantification and mapping, geo-disaster damage and risk assessment, urban planning and smart city development. This book focuses on the fundamental and applied research in these domains, aiming to promote exchanges and communications, share the research outcomes of scientists worldwide and to put these achievements better social use. This Special Issue collects fourteen high-quality research papers and is expected to provide a useful reference and technical support for graduate students, scientists, civil engineers and experts of governments to valorize scientific research

Multi-scale modelling of effluent dispersion in the marine environment

This research aimed to investigate whether the unique numerical methods available within CFD model software Fluidity could progress the state– of–the–art in various aspects of modelling effluent dispersion within the marine environment. Fluidity contains a large library of models and numerical methods that enable modelling of flow processes at a wide range of scales. It has been proven to perform well when used for massively– parallel simulations (i.e. it scales well), and it has the un–common facility of unstructured mesh adaptivity, which has the prospect of significantly increasing the efficiency of CFD simulations when guided skillfully. This research also forms part of a longer–term project to create a coupled (or even single) model of effluent dispersion that represents influencing factors from a wide range of scales (from tidal currents down to turbulent eddies) entirely using CFD techniques. As such, one aspect of the research was to validate the numerical methods available within Fluidity for use in modelling effluent dispersion. To facilitate this validation, some of the model studies investigate aspects of effluent dispersion modelling from a hypothetical outfall site off the North–East coast of the United Kingdom. Studies were performed in a series of stages in which key aspects of effluent dispersion modelling were addressed. CFD models were created of near–field jet dispersion, tidal motion, and far–field plume dispersion. Idealised test cases were also performed to investigate the performance of advection–diffusion solver methods. At each stage the aim was to investigate the benefit of novel numerical modelling techniques and compare their accuracy and efficiency to existing methods. A set of near–field buoyant jet dispersion CFD models were created, one representing conditions associated with power, and combined power and desalination plants, and one representing conditions typically associated with desalination discharge. These CFD models utilised a mesh adaptivity algorithm to optimise mesh resolution during the course of the simulation. Model predictions were compared with published laboratory data and the predictions from validated integral models. An assessment was made of when CFD offers a benefit over other modelling options, and when it might be sufficient to use cheaper tools. There was also a discussion of the effectiveness of mesh adaptivity in increasing model efficiency, together with advice for how and when it is best to use mesh adaptivity when modelling buoyant jet dispersion. Model results showed that with modest parallel computing resources and expertise, high–resolution simulations of jet dynamics can be achieved with reasonable accuracy using CFD modelling. A model was created of tidal flow within the European continental shelf and results were compared to a large database of tide gauge measurements. This model took advantage of recently published methods for ocean model meshing and coastline resolution reduction. The purpose of this study was to confirm that these methods offered a benefit to model accuracy and efficient, and also that Fluidity could be used to accurately generate the tidal forcing boundary conditions for a far–field model of effluent dispersion at a hypothetical outfall site. The predictions of M2 tide amplitude in the vicinity of the outfall site had an average error of 10.1% compared with tide gauge measurements. The predictions of S2 tide amplitude in the vicinity of the outfall site were even closer to tide gauge measurements, with an average error of 3.7%. The speed of the model solve showed a vast improvement over a previous comparison model study, with 37 days of tidal motion being simulated in 15.2 hours (58.4 seconds of simulation for each second of solving), compared to the comparison simulation with a similar level of accuracy, which simulated 2 seconds of tidal motion for every second of solver time. A series of simplified test cases were run to assess a commonly–used advection–diffusion solution method from the library of those available within Fluidity. This work was intended to give general confidence that the numerical methods available within Fluidity are suitable for modelling coastal processes and so give confidence in later multi–scale results. The test cases chosen were relevant to coastal dispersion, including those testing tracer advection, diffusion, point sources and stratification. The method compared well with results published using world–leading free surface modelling software, Open TELEMAC. A model was created of the dispersion of neutrally–buoyant dissolved pollutant from a hypothetical outfall. The assumed effluent is typical of that released from a manufacturing plant. The aim of this modelling was to validate the use of Fluidity for modelling effluent dispersion within the coastal zone, and also investigate the benefit of using 2–d horizontal mesh adaptivity to optimise model mesh resolution during the course of the simulation. It was shown that the use of mesh adaptivity improved model efficiency, significantly lowering the effect of numerical diffusion. Finally, a short outline was given of a prospective strategy for producing a coupled–model of effluent dispersion, using as a basis the techniques developed within this thesis. The proposed coupled model of effluent dispersion would include a near–field jet model two–way (i.e. “fully– coupled”) to a far–field plume model. Tidal forcing would be provided by a one–way coupled tidal model. Fluidity is capable of modelling all of these processes and so third party coupling software would be unnecessary.Open Acces

Remote Sensing

This dual conception of remote sensing brought us to the idea of preparing two different books; in addition to the first book which displays recent advances in remote sensing applications, this book is devoted to new techniques for data processing, sensors and platforms. We do not intend this book to cover all aspects of remote sensing techniques and platforms, since it would be an impossible task for a single volume. Instead, we have collected a number of high-quality, original and representative contributions in those areas

Publicationes Instituti Geographici Universitatis Tartuensis 110

Lifelong Learning ProgrammeAntti Roose: Progressing water geography discourses in the framework of the Erasmus seminar series - Silvia Piovan and Pierpaolo Faggi: The tradition of the European Seminar on Geography of Water in Padova: Experience in research and training - Leandro del Moral, Maria Fernanda Pita, Belén Pedregal, Nuria Hernández-Mora, Natalia Limones: Current paradigms in the management of water: Resulting information needs - Arvo Järvet: Morphological assessment of the quality of running water bodies for water management planning - Milada Matoušková and Kateřina Šmerousová: Hydromorphological reference condition of streams based on the European Water Framework Directive - Andrea Corsale and Giovanni Sistu: The changing relations among resources, communities and institutions in Sardinian wetlands - Franca Battigelli and Andrea Guaran: Drinking water(s) in Italy: Bottled, tap or kiosk water? - Levente Ronczyk, Szabolcs Czigány, Zoltan Wilhelm: Urban water damages in Pécs triggered by extreme weather events - Daniela Zlatunova and Panka Babukova: Flood risk assessment – a basis for sustainable spatial development. Case study: the Republic of Bulgaria - Chronicle of European seminars of water geography 2005–2014:Tartu 2005, Sevilla 2006, Sofia 2008, Udine 2009, Cluj-Napoca 2010, Cagliari 2011, Munich–Fischbachau 2012, Zadar 2013, Padova 201

Proceedings of the GIS Research UK 18th Annual Conference GISRUK 2010

This volume holds the papers from the 18th annual GIS Research UK (GISRUK). This year the conference, hosted at University College London (UCL), from Wednesday 14 to Friday 16 April 2010. The conference covered the areas of core geographic information science research as well as applications domains such as crime and health and technological developments in LBS and the geoweb. UCL’s research mission as a global university is based around a series of Grand Challenges that affect us all, and these were accommodated in GISRUK 2010. The overarching theme this year was “Global Challenges”, with specific focus on the following themes: * Crime and Place * Environmental Change * Intelligent Transport * Public Health and Epidemiology * Simulation and Modelling * London as a global city * The geoweb and neo-geography * Open GIS and Volunteered Geographic Information * Human-Computer Interaction and GIS Traditionally, GISRUK has provided a platform for early career researchers as well as those with a significant track record of achievement in the area. As such, the conference provides a welcome blend of innovative thinking and mature reflection. GISRUK is the premier academic GIS conference in the UK and we are keen to maintain its outstanding record of achievement in developing GIS in the UK and beyond

Terrain synthesis: the creation, management, presentation and validation of artificial landscapes

'Synthetic Terrain' is the term used for artificially-composed computer-based Digital Terrain Models (DTMs) created by a combination of techniques and heavily influenced by Earth Sciences applications. The synthetic landscape is created to produce 'geographically acceptable', 'realistic' or 'valid' computer-rendered landscapes, maps and 3D images, which are themselves based on synthetic terrain Digital Elevation Models (OEMs). This thesis examines the way in which mainly physical landscapes can be synthesised, and presents the techniques by which terrain data sets can be managed (created, manipulated, displayed and validated), both for academic reasons and to provide a convenient and cost-effective alternative to expensive 'real world' data sets. Indeed, the latter are collected by ground-based or aerial surveying techniques (e.g. photogrammetry), normally at considerable expense, depending on the scale, resolution and type required. The digital information for a real map could take months to collect, process and reproduce, possibly involving demanding Information Technology (IT) resources and sometimes complicated by differing (or contradictory) formats. Such techniques are invalid if the region lies within an 'unfriendly' or inaccessible part of the globe, where (for example), overflying or ground surveys are forbidden. Previous attempts at synthesising terrain have not necessarily aimed at realism. Digital terrain sets have been created by using fractal mathematical models, as 'special effects' for the entertainment industry (e.g. science fiction 'alien' landscapes' for motion pictures and arcade games) or for artistic reasons. There are no known examples of synthesised DTMs being created with such a wide range of requirements and functionality, and with such a regard to validation and realism. This thesis addresses the whole concept of producing' alternative' landscapes in artificial form - nearly 22 years of research aimed at creating' geographically-sensible' synthetic terrain is described with the emphasis on the last 5 years, when this PhD thesis was conceived. These concepts are based on radical, inexpensive and rapid techniques for synthesising terrain, yet value is also placed on the 'validity', realism and 'fitness for purpose' of such models. The philosophy - or the 'thought processes' - necessary to achieve the development of the algorithms leading to synthesised DTMs is one of the primary achievement of the research. This in turn led to the creation of an interactive software package called GEOFORMA, which requires some manual intervention in the form of preliminary terrain classification. The sequence is thus: the user can choose to create terrain or landform assemblages without reference to any real world area. Alternatively, he can select a real world region or a 'typical' terrain type on a 'dial up' basis, which requires a short period of intensive parametric analysis based on research into established terrain classification techniques (such as fractals and other mathematical routines, process-response models etc.) The creates a composite synthesised terrain model of high quality and realism, a factor examined both qualitatively and quantitatively. Although the physical terrain is the primary concern, similar techniques are applied to the human landscape, noting such attributes as the density, type, nature and distribution of settlements, transport systems etc., and although this thread of the research is limited in scope compared with the physical landscape synthesis, some spectacular results are presented. The system also creates place names based on a simple algorithm. Fluvial landscapes, upland regions and coastlines have been selected from the many possible terrain types for 'treatment', and the thesis gives each of these sample landscapes a separate chapter with appropriate illustrations from this original and extensive research. Finally, and inevitably, the work also poses questions in attempting to provide answers, this is perhaps inevitable in a relatively new genre, encompassing so many disciplines, and with relatively sparse literature on the subject