2,133 research outputs found
Artificial Intelligence Based Classification for Urban Surface Water Modelling
Estimations and predictions of surface water runoff can provide very useful insights, regarding flood risks in urban areas. To automatically predict the flow behaviour of the rainfall-runoff water, in real-world satellite images, it is important to precisely identify permeable and impermeable areas. This identification indicates and helps to calculate the amount of surface water, by taking into account the amount of water being absorbed in a permeable area and what remains on the impermeable area. In this research, a model of surface water has been established, to predict the behavioural flow of rainfall-runoff water. This study employs a combination of image processing, artificial intelligence and machine learning techniques, for automatic segmentation and classification of permeable and impermeable areas, in satellite images. These techniques investigate the image classification approaches for classifying three land-use categories (roofs, roads, and pervious areas), commonly found in satellite images of the earth’s surface. Three different classification scenarios are investigated, to select the best classification model. The first scenario involves pixel by pixel classification of images, using Classification Tree and Random Forest classification techniques, in 2 different settings of sequential and parallel execution of algorithms. In the second classification scenario, the image is divided into objects, by using Superpixels (SLIC) segmentation method, while three kinds of feature sets are extracted from the segmented objects. The performance of eight different supervised machine learning classifiers is probed, using 5-fold cross-validation, for multiple SLIC values, while detailed performance comparisons lead to conclusions about the classification into different classes, regarding Object-based and Pixel-based classification schemes. Pareto analysis and Knee point selection are used to select SLIC value and the suitable type of classification, among the aforementioned two. Furthermore, a new diversity and weighted sum-based ensemble classification model, called ParetoEnsemble, is proposed, in this classification scenario. The weights are applied to selected component classifiers of an ensemble, creating a strong classifier, where classification is done based on multiple votes from candidate classifiers of the ensemble, as opposed to individual classifiers, where classification is done based on a single vote, from only one classifier. Unbalanced and balanced data-based classification results are also evaluated, to determine the most suitable mode, for satellite image classifications, in this study. Convolutional Neural Networks, based on semantic segmentation, are also employed in the classification phase, as a third scenario, to evaluate the strength of deep learning model SegNet, in the classification of satellite imaging. The best results, from the three classification scenarios, are compared and the best classification method, among the three scenarios, is used in the next phase of water modelling, with the InfoWorks ICM software, to explore the potential of modelling process, regarding a partially automated surface water network. By using the parameter settings, with a specified amount of simulated rain falling, onto the imaged area, the amount of surface water flow is estimated, to get predictions about runoff situations in urban areas, since runoff, in such a situation, can be high enough to pose a dangerous flood risk. The area of Feock, in Cornwall, is used as a simulation area of study, in this research, where some promising results have been derived, regarding classification and modelling of runoff. The correlation coefficient estimation, between classification and runoff accuracy, provides useful insight, regarding the dependence of runoff performance on classification performance. The trained system was tested on some unknown area images as well, demonstrating a reasonable performance, considering the training and classification limitations and conditions. Furthermore, in these unknown area images, reasonable estimations were derived, regarding surface water runoff. An analysis of unbalanced and balanced data-based classification and runoff estimations, for multiple parameter configurations, provides aid to the selection of classification and modelling parameter values, to be used in future unknown data predictions. This research is founded on the incorporation of satellite imaging into water modelling, using selective images for analysis and assessment of results. This system can be further improved, and runoff predictions of high precision can be better achieved, by adding more high-resolution images to the classifiers training. The added variety, to the trained model, can lead to an even better classification of any unknown image, which could eventually provide better modelling and better insights into surface water modelling. Moreover, the modelling phase can be extended, in future research, to deal with real-time parameters, by calibrating the model, after the classification phase, in order to observe the impact of classification on the actual calibration
Remote real-time monitoring of subsurface landfill gas migration
The cost of monitoring greenhouse gas emissions from landfill sites is of major concern for regulatory authorities. The current monitoring procedure is recognised as labour intensive, requiring agency inspectors to physically travel to perimeter borehole wells in rough terrain and manually measure gas concentration levels with expensive hand-held instrumentation. In this article we present a cost-effective and efficient system for remotely monitoring landfill subsurface migration of methane and carbon dioxide concentration levels. Based purely on an autonomous sensing architecture, the proposed sensing platform was capable of performing complex analytical measurements in situ and successfully communicating the data remotely to a cloud database. A web tool was developed to present the sensed data to relevant stakeholders. We report our experiences in deploying such an approach in the field over a period of approximately 16 months
Applications of complex adaptive systems approaches to coastal systems
This thesis investigatesth e application of complex adaptives ystemsa pproaches
(e. g. Artificial Neural Networks and Evolutionary Computation) to the study of coastal
hydrodynamica nd morphodynamicb ehaviour.T raditionally, nearshorem orphologicalc oastal
systems tudiesh ave developeda n understandingo f thosep hysicalp rocesseso ccurringo n both
short temporal, and small spatial scales with a large degree of success. The associated
approachesa nd conceptsu sedt o study the coastals ystema t theses calesh ave Primarily been
linear in nature.H owever,w hent hesea pproachetso studyingt he coastals ystema re extendedto
investigating larger temporal and spatial scales,w hich are commensuratew ith the aims of
coastal managementr, esults have had less success.T he lack of successi n developing an
understandingo f large scalec oastalb ehaviouri s to a large extent attributablet o the complex
behavioura ssociatedw ith the coastals ystem.I bis complexity arises as a result of both the
stochastic and chaotic nature of the coastal system. This allows small scale system
understandingto be acquiredb ut preventst he Largers caleb ehaviourt o be predictede ffectively.
This thesis presentsf our hydro-morphodynamicc ase studies to demonstratet he utility of
complex adaptives ystema pproachesfo r studying coastals ystems.T he first two demonstrate
the application of Artificial Neural Networks, whilst the latter two illustrate the application of
EvolutionaryC omputation.C aseS tudy #I considerst he natureo f the discrepancyb etweent he
observedl ocation of wave breakingp atternso ver submergeds andbarsa nd the actual sandbar
locations.A rtificial Neural Networks were able to quantitativelyc orrectt he observedlo cations
to produce reliable estimates of the actual sand bar locations. Case Study #2 considers the
developmenot f an approachf or the discriminationo f shorelinel ocation in video imagesf or the
productiono f intertidal mapso f the nearshorer egion. In this caset he systemm odelledb y the
Artificial Neural Network is the nature of the discrimination model carried out by the eye in
delineating a shoreline feature between regions of sand and water. The Artificial Neural
Network approachw as shownt o robustly recognisea rangeo f shorelinef eaturesa t a variety of
beaches and hydrodynamic settings. Case Study #3 was the only purely hydrodynamic study
consideredin the thesis.I t investigatedth e use of Evolutionary Computationt o provide means
of developing a parametric description of directional wave spectra in both reflective and nonreflective
conditions. It is shown to provide a unifying approach which produces results which
surpassedth ose achievedb y traditional analysisa pproachese vent hough this may not strictly
have been considered as a fidly complex system. Case Study #4 is the most ambitious
applicationa nd addressetsh e needf or data reductiona s a precursorw hen trying to study large
scalem orphodynamicd ata sets.I t utilises EvolutionaryC omputationa pproachesto extractt he
significant morphodynamic variability evidenced in both directly and remotely sampled
nearshorem orphologiesS. ignificantd atar eductioni s achievedw hilst reWning up to 90% of the
original variability in the data sets.
These case studies clearly demonstrate the ability of complex adaptive systems to be
successfidly applied to coastal system studies. This success has been shown to equal and
sometimess urpasst he results that may be obtained by traditional approachesT. he strong
performance of Complex Adaptive System approaches is closely linked to the level of
complexity or non-linearity of the system being studied. Based on a qualitative evaluation,
Evolutionary Computation was shown to demonstrate an advantage over Artificial Neural
Networks in terms of the level of new insights which may be obtained. However, utility also
needs to consider general ease of applicability and ease of implementation of the study
approach.I n this sense,A rtificial Neural Networks demonstratem ore utility for the study of
coastals ystems.T he qualitative assessmenatp proachu sedt o evaluatet he cases tudiesi n this
thesis, may be used as a guide for choosingt he appropriatenesso f either Artificial Neural
Networks or Evolutionary Computation for future coastal system studies
A Global Human Settlement Layer from optical high resolution imagery - Concept and first results
A general framework for processing of high and very-high resolution imagery for creating a Global Human Settlement Layer (GHSL) is presented together with a discussion on the results of the first operational test of the production workflow. The test involved the mapping of 24.3 millions of square kilometres of the Earth surface spread over four continents, corresponding to an estimated population of 1.3 billion of people in 2010. The resolution of the input image data ranges from 0.5 to 10 meters, collected by a heterogeneous set of platforms including satellite SPOT (2 and 5), CBERS-2B, RapidEye (2 and 4), WorldView (1 and 2), GeoEye-1, QuickBird-2, Ikonos-2, and airborne sensors. Several imaging modes were tested including panchromatic, multispectral and pan-sharpened images. A new fully automatic image information extraction, generalization and mosaic workflow is presented that is based on multiscale textural and morphological image features extraction. New image feature compression and optimization are introduced, together with new learning and classification techniques allowing for the processing of HR/VHR image data using low-resolution thematic layers as reference. A new systematic approach for quality control and validation allowing global spatial and thematic consistency checking is proposed and applied. The quality of the results are discussed by sensor, by band, by resolution, and eco-regions. Critical points, lessons learned and next steps are highlighted.JRC.G.2-Global security and crisis managemen
Collaborative sparse regression using spatially correlated supports - Application to hyperspectral unmixing
This paper presents a new Bayesian collaborative sparse regression method for
linear unmixing of hyperspectral images. Our contribution is twofold; first, we
propose a new Bayesian model for structured sparse regression in which the
supports of the sparse abundance vectors are a priori spatially correlated
across pixels (i.e., materials are spatially organised rather than randomly
distributed at a pixel level). This prior information is encoded in the model
through a truncated multivariate Ising Markov random field, which also takes
into consideration the facts that pixels cannot be empty (i.e, there is at
least one material present in each pixel), and that different materials may
exhibit different degrees of spatial regularity. Secondly, we propose an
advanced Markov chain Monte Carlo algorithm to estimate the posterior
probabilities that materials are present or absent in each pixel, and,
conditionally to the maximum marginal a posteriori configuration of the
support, compute the MMSE estimates of the abundance vectors. A remarkable
property of this algorithm is that it self-adjusts the values of the parameters
of the Markov random field, thus relieving practitioners from setting
regularisation parameters by cross-validation. The performance of the proposed
methodology is finally demonstrated through a series of experiments with
synthetic and real data and comparisons with other algorithms from the
literature
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