Measuring oscillating walking paths with a LIDAR

This work describes the analysis of different walking paths registered using a Light Detection And Ranging (LIDAR) laser range sensor in order to measure oscillating trajectories during unsupervised walking. The estimate of the gait and trajectory parameters were obtained with a terrestrial LIDAR placed 100 mm above the ground with the scanning plane parallel to the floor to measure the trajectory of the legs without attaching any markers or modifying the floor. Three different large walking experiments were performed to test the proposed measurement system with straight and oscillating trajectories. The main advantages of the proposed system are the possibility to measure several steps and obtain average gait parameters and the minimum infrastructure required. This measurement system enables the development of new ambulatory applications based on the analysis of the gait and the trajectory during a walk.

Discriminating crop, weeds and soil surface with a terrestrial LIDAR sensor

In this study, the evaluation of the accuracy and performance of a light detection and ranging (LIDAR) sensor for vegetation using distance and reflection measurements aiming to detect and discriminate maize plants and weeds from soil surface was done. The study continues a previous work carried out in a maize field in Spain with a LIDAR sensor using exclusively one index, the height profile. The current system uses a combination of the two mentioned indexes. The experiment was carried out in a maize field at growth stage 12–14, at 16 different locations selected to represent the widest possible density of three weeds: Echinochloa crus-galli (L.) P.Beauv., Lamium purpureum L., Galium aparine L.and Veronica persica Poir.. A terrestrial LIDAR sensor was mounted on a tripod pointing to the inter-row area, with its horizontal axis and the field of view pointing vertically downwards to the ground, scanning a vertical plane with the potential presence of vegetation. Immediately after the LIDAR data acquisition (distances and reflection measurements), actual heights of plants were estimated using an appropriate methodology. For that purpose, digital images were taken of each sampled area. Data showed a high correlation between LIDAR measured height and actual plant heights (R2 = 0.75). Binary logistic regression between weed presence/absence and the sensor readings (LIDAR height and reflection values) was used to validate the accuracy of the sensor. This permitted the discrimination of vegetation from the ground with an accuracy of up to 95%. In addition, a Canonical Discrimination Analysis (CDA) was able to discriminate mostly between soil and vegetation and, to a far lesser extent, between crop and weeds. The studied methodology arises as a good system for weed detection, which in combination with other principles, such as vision-based technologies, could improve the efficiency and accuracy of herbicide spraying.

Päätöspuun käyttö tutkamaalien initialisoinnissa

Suomen ilmatilaa valvotaan reaaliaikaisesti, pääasiassa ilmavalvontatutkilla. Ilmatilassa on lentokoneiden lisäksi paljon muitakin kohteita, jotka tutka havaitsee. Tutka lähettää nämä tiedot edelleen ilmavalvontajärjestelmään. Ilmavalvontajärjestelmä käsittelee tiedot, sekä lähettää ne edelleen esitysjärjestelmään. Esitysjärjestelmässä tiedot esitetään synteettisinä merkkeinä, seurantoina joista käytetään nimitystä träkki. Näiden tietojen puitteissa sekä oman ammattitaitonsa perusteella ihmiset tekevät päätöksiä. Tämän työn tarkoituksena on tutkia tutkan havaintoja träkkien initialisointipisteessä siten, että voitaisiin määritellä tyypillinen rakenne sille mikä on oikea ja mikä väärä tai huono träkki. Tämän lisäksi tulisi ennustaa, mitkä Irakeista eivät aiheudu ilma- aluksista. Saadut tulokset voivat helpottaa työtä havaintojen tulkinnassa - jokainen lintuparvi ei ole ehdokas seurannaksi. Havaintojen luokittelu voidaan tehdä joko neurolaskennalla tai päätöspuulla. Neurolaskenta tehdään neuroverkoilla, jotka koostuvat neuroneista. Päätöspuu- luokittelijat ovat oppivia tietorakenteita kuten neuroverkotkin. Yleisin päätöpuu on binääripuu. Tämän työn tavoitteena on opettaa päätöspuuluokittelija havaintojen avulla siten, että se pystyy luokittelemaan väärät havainnot oikeista. Neurolaskennan mahdollisuuksia tässä työssä ei käsitellä kuin teoreettisesti. Työn tuloksena voi todeta, että päätöspuuluokittelijat ovat erittäin kykeneviä erottamaan oikeat havainnot vääristä. Vaikka tulokset olivat rohkaiseva, lisää tutkimusta tarvitaan määrittelemään luotettavammin tekijät, jotka parhaiten suorittavat luokittelun.

Conditioning of multiple-point statistics facies simulations to tomographic images

Geophysical tomography captures the spatial distribution of the underlying geophysical property at a relatively high resolution, but the tomographic images tend to be blurred representations of reality and generally fail to reproduce sharp interfaces. Such models may cause significant bias when taken as a basis for predictive flow and transport modeling and are unsuitable for uncertainty assessment. We present a methodology in which tomograms are used to condition multiple-point statistics (MPS) simulations. A large set of geologically reasonable facies realizations and their corresponding synthetically calculated cross-hole radar tomograms are used as a training image. The training image is scanned with a direct sampling algorithm for patterns in the conditioning tomogram, while accounting for the spatially varying resolution of the tomograms. In a post-processing step, only those conditional simulations that predicted the radar traveltimes within the expected data error levels are accepted. The methodology is demonstrated on a two-facies example featuring channels and an aquifer analog of alluvial sedimentary structures with five facies. For both cases, MPS simulations exhibit the sharp interfaces and the geological patterns found in the training image. Compared to unconditioned MPS simulations, the uncertainty in transport predictions is markedly decreased for simulations conditioned to tomograms. As an improvement to other approaches relying on classical smoothness-constrained geophysical tomography, the proposed method allows for: (1) reproduction of sharp interfaces, (2) incorporation of realistic geological constraints and (3) generation of multiple realizations that enables uncertainty assessment.

Interferometría SAR en las islas Shetlend del Sur: modelo numérico de elevaciones de la Isla Decepción

La interferometría con imágenes de radar de apertura sintética (SAR: Synthetic Aperture Radar) desde satélite es una técnica que permite obtener información altimétrica del relieve terrestre, siendo especialmente útil en áreas remotas. Este trabajo muestra una aplicación de esta técnica en las islas Shetland del Sur (Antártida). Para ello se han utilizado imágenes SAR obtenidas por los satélites ERS (European Remote Sensing) de la Agencia Espacial Europea (ESA: European Space Agency) y un proceso interferométrico desarrollado entre el Departament de Geodinàmica i Geofísica de la Universitat de Barcelona y el Institut Cartogràfic de Catalunya.

Proportionality and Party Success in Europe

This thesis consists of four articles and an introductory section. The main research questions in all the articles are about proportionality and party success in Europe, at European, national or district levels. Proportionality in this thesis denotes the proximity of seat shares parties receive compared to their respective vote shares, after the electoral system’s allocation process. This proportionality can be measured through numerous indices that illustrate either the overall proportionality of an electoral system or a particular election. The correspondence of a single party’s seat shares to its vote shares can also be measured. The overall proportionality is essential in three of the articles (1, 2 and 4), where the system’s performance is studied by means of plots. In article 3, minority party success is measured by advantage-ratios that reveal single party’s winnings or losses in the votes to seat allocation process. The first article asks how proportional are the European parliamentary (EP) electoral systems, how do they compare with results gained from earlier studies and how do the EP electoral systems treat different sized parties. The reasons for different outcomes are looked for in explanations given by traditional electoral studies i.e. electoral system variables. The countries studied (EU15) apply electoral systems that vary in many important aspects, even though a certain amount of uniformity has been aspired to for decades. Since the electoral systems of the EP elections closely resemble the national elections, the same kinds of profiles emerge as in the national elections. The electoral systems indeed treat the parties differentially and six different profile types can be found. The counting method seems to somewhat determine the profile group, but the strongest variables determining the shape of a countries’ profile appears to be the average district magnitude and number of seats allocated to each country. The second article also focuses on overall proportionality performance of an electoral system, but here the focus is on the impact of electoral system changes. I have developed a new method of visualizing some previously used indices and some new indices for this purpose. The aim is to draw a comparable picture of these electoral systems’ changes and their effects. The cases, which illustrate this method, are four elections systems, where a change has occurred in one of the system variables, while the rest remained unchanged. The studied cases include the French, Greek and British European parliamentary systems and the Swedish national parliamentary system. The changed variables are electoral type (plurality changed to PR in the UK), magnitude (France splitting the nationwide district into eight smaller districts), legal threshold (Greece introducing a three percent threshold) and counting method (d’Hondt was changed to modified Sainte-Laguë in Sweden). The radar plots from elections after and before the changes are drawn for all country cases. When quantifying the change, the change in the plots area that is created has also been calculated. Using these radar plots we can observe that the change in electoral system type, magnitude, and also to some extent legal threshold had an effect on overall proportionality and accessibility for small parties, while the change between the two highest averages counting method had none. The third article studies the success minority parties have had in nine electoral systems in European heterogeneous countries. This article aims to add more motivation as to why we should care how different sized parties are treated by the electoral systems. Since many of the parties that aspire to represent minorities in European countries are small, the possibilities for small parties are highlighted. The theory of consociational (or power-sharing) democracy suggests that, in heterogeneous societies, a proportional electoral system will provide the fairest treatment of minority parties. The OSCE Lund Recommendations propose a number of electoral system features, which would improve minority representation. In this article some party variables, namely the unity of the minority parties and the geographical concentration of the minorities were included among possible explanations. The conclusions are that the central points affecting minority success were indeed these non-electoral system variables rather than the electoral system itself. Moreover, the size of the party was a major factor governing success in all the systems investigated; large parties benefited in all the studied electoral systems. In the fourth article the proportionality profiles are again applied, but this time to district level results in Finnish parliamentary elections. The level of proportionality distortion is also studied by way of indices. The average magnitudes during the studied periodrange from 7.5 to 26.2 in the Finnish electoral districts and this opens up unequal opportunities for parties in different districts and affects the shape of the profiles. The intra-country case allows the focus to be placed on the effect of district magnitude, since all other electoral systems are kept constant in an intra-country study. The time span in the study is from 1962 to 2007, i.e. the time that the districts have largely been the same geographically. The plots and indices tell the same story, district magnitude and electoral alliances matter. The district magnitude is connected to the overall proportionality of the electoral districts according to both indices, and the profiles are, as expected, also closer to perfect proportionality in large districts. Alliances have helped some small parties to gain a much higher seat share than their respective vote share and these successes affect some of the profiles. The profiles also show a consistent pattern of benefits for the small parties who ally with the larger parties.

Sistema de visualización SIG del Servei Meteorològic de Catalunya

El sistema de visualización SIG del Servei Meteorològic de Catalunya (SMC) consiste en un sistema que visualiza la información meteorológica del SMC mediante un visor SIG. La herramienta permitirá a los técnicos del SMC poder consultar productos meteorológicos, como modelos numéricos, productos de Meteosat, radar, descargas eléctricas, etc. El sistema se compone de un servidor MapServer, utilizando MapCache como sistema de caché, y de un visor SIG web implementado en JavaScript, utilizando las librerías Dojo Toolkit y OpenLayers.

From Regional Landslide Detection to Site-Specific Slope Deformation Monitoring and Modelling Based on Active Remote Sensors

Landslide processes can have direct and indirect consequences affecting human lives and activities. In order to improve landslide risk management procedures, this PhD thesis aims to investigate capabilities of active LiDAR and RaDAR sensors for landslides detection and characterization at regional scales, spatial risk assessment over large areas and slope instabilities monitoring and modelling at site-specific scales. At regional scales, we first demonstrated recent boat-based mobile LiDAR capabilities to model topography of the Normand coastal cliffs. By comparing annual acquisitions, we validated as well our approach to detect surface changes and thus map rock collapses, landslides and toe erosions affecting the shoreline at a county scale. Then, we applied a spaceborne InSAR approach to detect large slope instabilities in Argentina. Based on both phase and amplitude RaDAR signals, we extracted decisive information to detect, characterize and monitor two unknown extremely slow landslides, and to quantify water level variations of an involved close dam reservoir. Finally, advanced investigations on fragmental rockfall risk assessment were conducted along roads of the Val de Bagnes, by improving approaches of the Slope Angle Distribution and the FlowR software. Therefore, both rock-mass-failure susceptibilities and relative frequencies of block propagations were assessed and rockfall hazard and risk maps could be established at the valley scale. At slope-specific scales, in the Swiss Alps, we first integrated ground-based InSAR and terrestrial LiDAR acquisitions to map, monitor and model the Perraire rock slope deformation. By interpreting both methods individually and originally integrated as well, we therefore delimited the rockslide borders, computed volumes and highlighted non-uniform translational displacements along a wedge failure surface. Finally, we studied specific requirements and practical issues experimented on early warning systems of some of the most studied landslides worldwide. As a result, we highlighted valuable key recommendations to design new reliable systems; in addition, we also underlined conceptual issues that must be solved to improve current procedures. To sum up, the diversity of experimented situations brought an extensive experience that revealed the potential and limitations of both methods and highlighted as well the necessity of their complementary and integrated uses.

Large slope deformations detection and monitoring along shores of the Potrerillos dam reservoir, Argentina, based on a small-baseline InSAR approach

The Argentina National Road 7 that crosses the Andes Cordillera within the Mendoza province to connect Santiago de Chile and Buenos Aires is particularly affected by natural hazards requiring risk management. Integrated in a research plan that intends to produce landslide susceptibility maps, we aimed in this study to detect large slope movements by applying a satellite radar interferometric analysis using Envisat data, acquired between 2005 and 2010. We were finally able to identify two large slope deformations in sandstone and clay deposits along gentle shores of the Potrerillos dam reservoir, with cumulated displacements higher than 25mm in 5years and towards the reservoir. There is also a body of evidences that these large slope deformations are actually influenced by the seasonal reservoir level variations. This study shows that very detailed information, such as surface displacements and above all water level variation, can be extracted from spaceborne remote sensing techniques; nevertheless, the limitations of InSAR for the present dataset are discussed here. Such analysis can then lead to further field investigations to understand more precisely the destabilising processes acting on these slope deformations.

Sadevälkkeen mallinnus ilmavalvontatutkajärjestelmää varten

Tutkat muodostavat Suomen rauhanajan ilmavalvonnan rungon. Ilmatilassa on lentokoneiden lisäksi paljon muitakin kohteita, jotka ilmavalvontatutka havaitsee. Naita ei toivottuja kaikuja kutsutaan välkkeeksi. Sadevälke on tilavuusvälkettä. Tämän työn tarkoituksena on löytää menetelmä tai malli, jolla voitaisiin mallintaa sadevälkkeen vaikutus ilmavalvontatutkassa. Toisaalta myös sadevälkkeen suodatus on työn keskeinen tavoite. Käytettyjä suodatusmenetelmiä olivat adaptiivinen suodatus ja doppler-suodatus. Suodinpankkiin eli doppler-suodatukseen lisättiin vielä CFAR Työn tuloksena voi todeta, että sadevälkkeen suodatus onnistui hyvin mutta itse sadevälkkeen mallintamista tulee kehittää edelleen. Työssä käytetyt menetelmät on esitetty algoritmimuodossa. Mittausaineiston keräys suoritettiin keskivalvontatutkalla ja SP-testerillä. Varsinaiset suodatuskokeet ja mallin testaus tehtiin Matlab-ohjelmistolla.

Archaeological Excavation Confirms the Geophysical Anomalies Recorded at the Cathedral of Tarragona - A Comparative Study

An integrated geophysical survey was conducted in September 2007 at the Cathedral of Tarragona (Catalonia, NE Spain), to search for archaeological remains of the Roman temple dedicated to the Emperor Augustus. Many hypotheses about its location have been put forward, the most recent ones suggesting it could be inside the present cathedral. Tarragona’s Cathedral, one of the most famous churches in Spain (12th century), was built during the evolution from the Romanesque to Gothic styles. As its area is rather wide, direct digging to detect hidden structures would be expensive and also interfere with religious services. Consequently, the use of detailed non-invasive analyses was preferred. A project including Electrical resistivity tomography (ERT) and Ground probing radar (GPR) was planned for a year and conducted during a week of intensive field survey. Both ERT and GPR provided detailed information about subsoil structures. Different ERT techniques and arrays were used, ranging from standard Wenner-Schlumberger 2D sections to full 3D electrical imaging using the MYG array. Electrical resistivity data were recorded extensively, making available many thousands of apparent resistivity points to obtain a complete 3D image after full inversion. The geophysical results were clear enough to persuade the archaeologists to excavate the area. The excavation confirmed the geophysical interpretation. In conclusion, the significant buried structures revealed by geophysical methods under the cathedral were confirmed by recent archaeological digging as the basement of the impressive Roman Temple that headed the Provincial Forum of Tarraco, seat of the Concilium of Hispania Citerior Province.

O desafio da delimitação de áreas de preservação permanente

A demarcação das áreas de proteção no topo de morros e ao longo dos divisores d'água é um processo complexo, dificultando a fiscalização e, por conseguinte, o fiel cumprimento da legislação. Como alternativa aos métodos tradicionalmente utilizados - mapas topográficos, levantamentos de campo e uso dos restituidores - na execução dessa tarefa, apresenta-se uma nova metodologia, alicerçada na modelagem numérica do relevo e implementada em um sistema de informações geográficas. O processo é todo automatizado e alicerça-se em um conceito relativamente novo de modelos digitais de elevação hidrologicamente consistentes, tendo como vantagens a confiabilidade e a reprodutibilidade dos resultados obtidos, além da economia óbvia de tempo e mão-de-obra. A partir da disponibilização gratuita pela NASA dos dados SRTM (Shuttle Radar Topography Mission) para todo o continente americano, os resultados indicaram claramente que a aplicação da Lei Florestal no Brasil passa a ser tão-somente uma vontade política.

Relações entre qualidade da água e uso do solo em Goiás: uma análise à escala da bacia hidrográfica

Este trabalho teve por objetivo principal investigar possíveis relações entre qualidade da água e uso do solo em bacias hidrográficas de abastecimento público em Goiás. Nesse sentido, foram compilados dados de 174 captações, operadas pelo Saneamento de Goiás entre janeiro/2002 e dezembro/2004. Médias anuais de seca e de cheia, de turbidez, cor aparente, pH, cloretos e índices de coliforme total e fecal foram relacionadas, por análise de componentes principais, em um índice de qualidade de água (IQA). Com base no mapa de cobertura e uso do solo de Goiás, à escala de 1:250.000, e um mosaico de imagens SRTM (Shuttle Radar Topography Mission), foram delimitadas as bacias de 89 das captações, para as quais foi calculado um Índice Normalizado de Vegetação Remanescente (NRVI). Cor aparente, turbidez, pH, ICT e ICF estiveram aquém dos padrões legalmente requeridos em até 62,43% das captações analisadas, principalmente nos períodos de cheia, quando os piores valores de IQA são observados. Os resultados indicaram que o IQA utilizado é sensível às variações sazonais e responde ao aporte de sedimentos e matéria orgânica por escoamento superficial. Da mesma forma, esse índice se relaciona, ainda que de forma tênue, às variações regionais nos valores de NRVI. Assim, novos estudos, levando-se em conta outros parâmetros de qualidade da água (como nitrogênio e fósforo) e diferentes escalas da paisagem (ex. zona ripária), são necessários, com vistas a uma melhor determinação dessas relações.

Análise comparativa de sensores de velocidade de deslocamento em função da superfície

Um dos fatores que influencia diretamente no desempenho de sistemas mecanizados é a velocidade de deslocamento pela sua importância no planejamento e na execução das operações agrícolas. O objetivo deste trabalho foi avaliar a acurácia de quatro sensores de velocidade, em condições de superfície asfáltica, solo com cobertura vegetal, aclives e declives, acelerações e desacelerações, submetidos a velocidades representativas para aplicações agrícolas. Foram ensaiados dois modelos comerciais de sensores de radar, um sensor de GPS e um sensor óptico. Foram identificadas diferenças significativas para as situações de solo com cobertura vegetal, acelerações e desacelerações. Para a superfície asfáltica, em situação de velocidade constante, os sensores avaliados não apresentaram desempenho com diferença significativa. Os sensores tipo radar demonstraram ser influenciados pela superfície com cobertura vegetal. Na superfície asfáltica, sob condições de aceleração e desaceleração, o sensor de GPS apresentou retardo nos valores de velocidade quando comparado com os demais.