A new approach for semi-automatic rock mass joints recognition from 3D point clouds

Rock mass characterization requires a deep geometric understanding of the discontinuity sets affecting rock exposures. Recent advances in Light Detection and Ranging (LiDAR) instrumentation currently allow quick and accurate 3D data acquisition, yielding on the development of new methodologies for the automatic characterization of rock mass discontinuities. This paper presents a methodology for the identification and analysis of flat surfaces outcropping in a rocky slope using the 3D data obtained with LiDAR. This method identifies and defines the algebraic equations of the different planes of the rock slope surface by applying an analysis based on a neighbouring points coplanarity test, finding principal orientations by Kernel Density Estimation and identifying clusters by the Density-Based Scan Algorithm with Noise. Different sources of information —synthetic and 3D scanned data— were employed, performing a complete sensitivity analysis of the parameters in order to identify the optimal value of the variables of the proposed method. In addition, raw source files and obtained results are freely provided in order to allow to a more straightforward method comparison aiming to a more reproducible research.

The Pliocene Mediterranean infilling of the Messinian Erosional Surface: New biostratigraphic data based on calcareous nannofossils (Bajo Segura Basin, SE Spain)

The Bajo Segura Basin (eastern Betic Cordillera) is a Mediterranean marginal basin where the Messinian Erosional Surface (MES), formed during the Messinian Salinity Crisis sea-level fall, is well developed. Overlying this major discontinuity the lower Pliocene transgressive sediments record the reflooding of the Mediterranean and the return to an open marine environment, the continental shelf being rebuilt after the Messinian erosion. The stratigraphic and biostratigraphic study of six sections allows two transgressive-regressive sequences filling the MES to be distinguished, correlated with the previously distinguished Mediterranean offshore seismic units. Ten calcareous nannofossil bioevents have been identified. The lower sequence can be dated according to nannofossil biozones NN12 to NN14 and the upper sequence by NN15 to NN16. The boundary between both lower Pliocene sedimentary sequences occur after the first common occurrence (FCO) of Discoaster asymmetricus found in the uppermost sediments of the lower sequence and before the first occurrence (FO) of Discoaster tamalis in the lowermost part of the upper sequence. Thus this sequence boundary can be estimated at between 4.1 and 4.0Ma ago.

Uso de nubes de puntos 3D para identificación y caracterización de familias de discontinuidades planas en afloramientos rocosos y evaluación de la calidad geomecánica

En este trabajo se estudia el uso de las nubes de puntos en 3D, es decir, un conjunto de puntos en un sistema de referencia cartesiano en R3, para la identificación y caracterización de las discontinuidades que afloran en un macizo rocoso y su aplicación al campo de la Mecánica de Rocas. Las nubes de puntos utilizadas se han adquirido mediante tres técnicas: sintéticas, 3D laser scanner y la técnica de fotogrametría digital Structure From Motion (SfM). El enfoque está orientado a la extracción y caracterización de familias de discontinuidades y su aplicación a la evaluación de la calidad de un talud rocoso mediante la clasificación geomecánica Slope Mass Rating (SMR). El contenido de la misma está dividido en tres bloques, como son: (1) metodología de extracción de discontinuidades y clasificación de la nube de puntos 3D; (2) análisis de espaciados normales en nubes de puntos 3D; y (3) análisis de la evaluación de la calidad geomecánica de taludes rocoso mediante la clasificación geomecánica SMR a partir de nubes de puntos 3D. La primera línea de investigación consiste en el estudio de las nubes de puntos 3D con la finalidad de extraer y caracterizar las discontinuidades planas presentes en la superficie de un macizo rocoso. En primer lugar, se ha recopilado información de las metodologías existentes y la disponibilidad de programas para su estudio. Esto motivó la decisión de investigar y diseñar un proceso de clasificación novedoso, que muestre todos los pasos para su programación e incluso ofreciendo el código programado a la comunidad científica bajo licencia GNU GPL. De esta forma, se ha diseñado una novedosa metodología y se ha programado un software que analiza nubes de puntos 3D de forma semi-automática, permitiendo al usuario interactuar con el proceso de clasificación. Dicho software se llama Discontinuity Set Extractor (DSE). El método se ha validado empleando nubes de puntos sintéticas y adquiridas con 3D laser scanner. En primer lugar, este código analiza la nube de puntos efectuando un test de coplanaridad para cada punto y sus vecinos próximos para, a continuación, calcular el vector normal de la superficie en el punto estudiado. En segundo lugar, se representan los polos de los vectores normales calculados en el paso previo en una falsilla estereográfica. A continuación se calcula la densidad de los polos y los polos con mayor densidad o polos principales. Estos indican las orientaciones de la superficie más representadas, y por tanto las familias de discontinuidades. En tercer lugar, se asigna a cada punto una familia en dependencia del ángulo formado por el vector normal del punto y el de la familia. En este punto el usuario puede visualizar la nube de puntos clasificada con las familias de discontinuidades que ha determinado para validar el resultado intermedio. En cuarto lugar, se realiza un análisis cluster en el que se determina la agrupación de puntos según planos para cada familia (clusters). A continuación, se filtran aquellos que no tengan un número de puntos suficiente y se determina la ecuación de cada plano. Finalmente, se exportan los resultados de la clasificación a un archivo de texto para su análisis y representación en otros programas. La segunda línea de investigación consiste en el estudio del espaciado entre discontinuidades planas que afloran en macizos rocosos a partir de nubes de puntos 3D. Se desarrolló una metodología de cálculo de espaciados a partir de nubes de puntos 3D previamente clasificadas con el fin de determinar las relaciones espaciales entre planos de cada familia y calcular el espaciado normal. El fundamento novedoso del método propuesto es determinar el espaciado normal de familia basándonos en los mismos principios que en campo, pero sin la restricción de las limitaciones espaciales, condiciones de inseguridad y dificultades inherentes al proceso. Se consideraron dos aspectos de las discontinuidades: su persistencia finita o infinita, siendo la primera el aspecto más novedoso de esta publicación. El desarrollo y aplicación del método a varios casos de estudio permitió determinar su ámbito de aplicación. La validación se llevó a cabo con nubes de puntos sintéticas y adquiridas con 3D laser scanner. La tercera línea de investigación consiste en el análisis de la aplicación de la información obtenida con nubes de puntos 3D a la evaluación de la calidad de un talud rocoso mediante la clasificación geomecánica SMR. El análisis se centró en la influencia del uso de orientaciones determinadas con distintas fuentes de información (datos de campo y técnicas de adquisición remota) en la determinación de los factores de ajuste y al valor del índice SMR. Los resultados de este análisis muestran que el uso de fuentes de información y técnicas ampliamente aceptadas pueden ocasionar cambios en la evaluación de la calidad del talud rocoso de hasta una clase geomecánica (es decir, 20 unidades). Asimismo, los análisis realizados han permitido constatar la validez del índice SMR para cartografiar zonas inestables de un talud. Los métodos y programas informáticos desarrollados suponen un importante avance científico para el uso de nubes de puntos 3D para: (1) el estudio y caracterización de las discontinuidades de los macizos rocosos y (2) su aplicación a la evaluación de la calidad de taludes en roca mediante las clasificaciones geomecánicas. Asimismo, las conclusiones obtenidas y los medios y métodos empleados en esta tesis doctoral podrán ser contrastadas y utilizados por otros investigadores, al estar disponibles en la web del autor bajo licencia GNU GPL.

Characterization of rock slopes through slope mass rating using 3D point clouds

Rock mass classification systems are widely used tools for assessing the stability of rock slopes. Their calculation requires the prior quantification of several parameters during conventional fieldwork campaigns, such as the orientation of the discontinuity sets, the main properties of the existing discontinuities and the geo-mechanical characterization of the intact rock mass, which can be time-consuming and an often risky task. Conversely, the use of relatively new remote sensing data for modelling the rock mass surface by means of 3D point clouds is changing the current investigation strategies in different rock slope engineering applications. In this paper, the main practical issues affecting the application of Slope Mass Rating (SMR) for the characterization of rock slopes from 3D point clouds are reviewed, using three case studies from an end-user point of view. To this end, the SMR adjustment factors, which were calculated from different sources of information and processes, using the different softwares, are compared with those calculated using conventional fieldwork data. In the presented analysis, special attention is paid to the differences between the SMR indexes derived from the 3D point cloud and conventional field work approaches, the main factors that determine the quality of the data and some recognized practical issues. Finally, the reliability of Slope Mass Rating for the characterization of rocky slopes is highlighted.

Implementation Feasibility of a Digital Nervous System for the Construction Industry: For Efficient and Effective Information Management across the Project Lifecycle

The construction industry has long been considered as highly fragmented and non-collaborative industry. This fragmentation sprouted from complex and unstructured traditional coordination processes and information exchanges amongst all parties involved in a construction project. This nature coupled with risk and uncertainty has pushed clients and their supply chain to search for new ways of improving their business process to deliver better quality and high performing product. This research will closely investigate the need to implement a Digital Nervous System (DNS), analogous to a biological nervous system, on the flow and management of digital information across the project lifecycle. This will be through direct examination of the key processes and information produced in a construction project and how a DNS can provide a well-integrated flow of digital information throughout the project lifecycle. This research will also investigate how a DNS can create a tight digital feedback loop that enables the organisation to sense, react and adapt to changing project conditions. A Digital Nervous System is a digital infrastructure that provides a well-integrated flow of digital information to the right part of the organisation at the right time. It provides the organisation with the relevant and up-to-date information it needs, for critical project issues, to aid in near real-time decision-making. Previous literature review and survey questionnaires were used in this research to collect and analyse data about information management problems of the industry – e.g. disruption and discontinuity of digital information flow due to interoperability issues, disintegration/fragmentation of the adopted digital solutions and paper-based transactions. Results analysis revealed efficient and effective information management requires the creation and implementation of a DNS.

Immigration and free movement in an unusual electoral race: what implications for the next political cycle? EPC Policy Brief, 20 May 2014

Immigration and freedom of movement of EU citizens are among the main issues debated throughout the European Parliament election campaign and have some potential in determining who tomorrow’s EU leaders will be. This Policy Brief looks at how the two policies are debated at national level – in France, Germany and the UK – and at EU level between the ‘top candidates’ for European Commission Presidency – Jean-Claude Juncker (EPP), Ska Keller (Greens), Martin Schulz (PES) and Guy Verhofstadt (ALDE) – who have participated in several public debates. Two different campaigns have been unfolding in front of EU citizens’ eyes. The tense debate that can be identified at national level on these issues, is not transferred to the EU level, where immigration and free movement are less controversial topics. Furthermore, although participating in European elections, national parties present agendas responding exclusively to the economic and social challenges of their Member State, while the candidates for the Commission Presidency bring forward ‘more European’ programmes. Hence, several aspects need to be reflected upon: What will the consequences of this discontinuity be? How will this impact the future European agenda in terms of immigration and free movement? What institutional consequences will there be? Answering these questions is not a simple task, however, this paper aims to identify the parameters that need to be taken into account and the political landscape which will determine the future EU agenda in terms of immigration and free movement.

The 2011 Constitutional reform in Morocco: more flaws than merits. Jean Monnet Occasional Paper No. 07/2014

Introduction. In the speech given to both Houses of Parliament on 11 October 2013 during the first parliamentary session, King Mohammed VI said that the “Moroccan democratic model” was “a precursor in the region as well as on the continental level.”1 Similarly, with the purpose of stressing the “democratic exceptionalism”2 of the country, the new government, led by Abdeilah Benkirane, emphasised that Morocco represents a “third way” compared to countries such as Tunisia, Libya or Egypt since it “…has not embarked on a limited process of reform from the top, driven and controlled by the King. Nor has it experienced a revolution brought a angry citizens rising up against the regime. Rather, it has chosen an alternate path based on a genuine partnership between the King and the PJD (Parti de la justice et du développement) that promises to bring about more far-reaching reform than palace alone would grant, without the disruption caused by uncontrolled popular upheaval.”4 It should not be at all surprising that the regime and the new Government consider Morocco a “democratic model” or a “third way.” After all, they are refe country. What is harder to understand is that when discussing the Arab uprisings, even prominent Western political leaders, representatives of the European Union institutions and the mainstream media (when they do not forget about Morocc to praise the process of democratic reform carried out by Mohammed VI. For example, on 12 September 2012, Hillary Clinton, former US Secretary of State, said, “in many ways, the United States looks to Morocco to be a leader and a model […] On political reform, we have all seen remarkable changes taking place across North Africa and the Middle East. I commend Morocco and your government for your efforts to stay ahead of these changes by holding free and fair elections, empowering the elected parliament, taking other steps to ensure that the government reflects the will of the people.”5 Similarly, former French President Nicolas Sarkozy sang the praises of the process that led to the adoption of the new 2011 Constitution: “King Mohammed VI has shown the path towards a profound, peaceful and modern transformation of Moroccan institutions and society […] France fully supports this exemplary process.” Interestingly enough, even at the European Union level the constitutional reform that took more far-reaching reform than palace alone would grant, without the disruption caused by uncontrolled popular upheaval.”4 It should not be at all surprising that the regime and the new Government consider Morocco a “democratic model” or a “third way.” After all, they are refe country. What is harder to understand is that when discussing the Arab uprisings, even prominent Western political leaders, representatives of the European Union institutions and the mainstream media (when they do not forget about Morocc to praise the process of democratic reform carried out by Mohammed VI. For example, on 12 September 2012, Hillary Clinton, former US Secretary of State, said, “in many ways, the United States looks to Morocco to be a leader and a model […] On political reform, we have all seen remarkable changes taking place across North Africa and the Middle East. I commend Morocco and your government for your efforts to stay ahead of these changes by holding free and fair elections, empowering the elected parliament, taking other steps to ensure that the government reflects the will of the people.”5 Similarly, former French President Nicolas Sarkozy sang the praises of the process that led to the adoption of the new 2011 Constitution: “King Mohammed VI has shown the path towards a profound, peaceful and modern transformation of Moroccan institutions and society […] France fully supports this exemplary process.” Interestingly enough, even at the European Union level the constitutional reform that took place in Morocco was considered an extremely positive step taken by the country, as well as a means to strengthen the cooperation between the EU and Morocco. Indeed, according to the High Representative Catherine Ashton, this reform “constitute[s] a significant response to the legitimate aspirations of the Moroccan people and [is] consistent with Morocco’s Advanced Status with the EU.”7 When it comes to the media, it is worth noting that following the ratification of the 2011 Constitution, The New York Times headlined: “All Hail the (Democratic) King.” Even sections of the academic literature have commended the constitutional reform carried out by the Moroccan Sovereign.9 In this paper I argue against the aforementioned idea, according to which Morocco should be considered a model in the region, and in particular I show that the constitution-making process, the 2011 Constitution and its subsequent implementation have more flaws than merits. Accordingly, this paper proceeds in five steps. First of all, I examine the reaction of the regime to the upheavals that broke out in the country after 20 February 2011. Secondly, I analyse the process of constitution showing its main strengths and weaknesses, and comparing it with other constituent processes that took place in the region following the Arab uprisings. In the third section, I highlight the most significant elements of continuity and discontinuity with the previous 1996 Constitution. The fourth section deals with the process of implementation: specifically process is proceeding quite slowly and that in some cases ordinary legislation is in contrast with the new Constitution and international human rights treaties. Moreover, I discuss the role that the judiciary and the Constitutional Court can play in the implementation and interpretation of the Constitution. Finally, I draw some concluding remarks.

Using multiple landscape genetic approaches to test the validity of genetic clusters in a species characterized by an isolation-by-distance pattern

Bayesian clustering methods are typically used to identify barriers to gene flow, but they are prone to deduce artificial subdivisions in a study population characterized by an isolation-by-distance pattern (IbD). Here we analysed the landscape genetic structure of a population of wild boars (Sus scrofa) from south-western Germany. Two clustering methods inferred the presence of the same genetic discontinuity. However, the population in question was characterized by a strong IbD pattern. While landscape-resistance modelling failed to identify landscape features that influenced wild boar movement, partial Mantel tests and multiple regression of distance matrices (MRDMs) suggested that the empirically inferred clusters were separated by a genuine barrier. When simulating random lines bisecting the study area, 60% of the unique barriers represented, according to partial Mantel tests and MRDMs, significant obstacles to gene flow. By contrast, the random-lines simulation showed that the boundaries of the inferred empirical clusters corresponded to the most important genetic discontinuity in the study area. Given the degree of habitat fragmentation separating the two empirical partitions, it is likely that the clustering programs correctly identified a barrier to gene flow. The differing results between the work published here and other studies suggest that it will be very difficult to draw general conclusions about habitat permeability in wild boar from individual studies.

La ruptura epistemológica de Bachelard a Balibar y Pêcheux

En el presente trabajo intentaremos analizar cierta serie o tradición de reflexiones sobre el conocimiento científico que lo caracterizan por su discontinuidad en relación al conocimiento ordinario o sentido común. El origen de esta serie puede localizarse en la obra de Gaston Bachelard y su peculiar estudio de los actos epistemológicos con los que se rompe con el pasado en una disciplina científica. Estos actos contrastan con lo que este autor califica como el "mito continuista" del empirismo. Esta posición será apropiada por Althusser y desarrollada por sus discípulos Balibar y Pêcheux. Intentaremos mostrar que el factor común de la discontinuidad no constituye ;una posición monolítica, sino que cabe reconocer, en las posiciones que consideramos, maneras diversas de entender la naturaleza de la misma. En este sentido, la revisión de las posiciones que Althusser efectuó en su "autocrítica" constituye un punto de observación privilegiado del abanico de alternativas que algunos de sus discípulos desarrollarían sobre bases diversas

La ruptura epistemológica de Bachelard a Balibar y Pêcheux

En el presente trabajo intentaremos analizar cierta serie o tradición de reflexiones sobre el conocimiento científico que lo caracterizan por su discontinuidad en relación al conocimiento ordinario o sentido común. El origen de esta serie puede localizarse en la obra de Gaston Bachelard y su peculiar estudio de los actos epistemológicos con los que se rompe con el pasado en una disciplina científica. Estos actos contrastan con lo que este autor califica como el "mito continuista" del empirismo. Esta posición será apropiada por Althusser y desarrollada por sus discípulos Balibar y Pêcheux. Intentaremos mostrar que el factor común de la discontinuidad no constituye ;una posición monolítica, sino que cabe reconocer, en las posiciones que consideramos, maneras diversas de entender la naturaleza de la misma. En este sentido, la revisión de las posiciones que Althusser efectuó en su "autocrítica" constituye un punto de observación privilegiado del abanico de alternativas que algunos de sus discípulos desarrollarían sobre bases diversas

Short-term spectral analysis of ODP Hole 114-704B

Short-term spectral analysis was carried out on geochemical logging data from ODP Site 704. The FFT was used to compute the amplitude spectra of short-term overlapping segments to produce depth-period-amplitude spectrograms of the logging data. The spectrograms provided a means of evaluating the significance of the observed periodic components. The periodic components that were consistently present and prominent across a given record interval were considered to be significant. Changes in the spectrogram characteristics seem to reflect changes in either lithology, sedimentation rates, or hiatuses and may therefore provide useful information to aid in stratigraphic and paleoenvironmental studies. The dominant periodicity during the late Pleistocene and Brunhes Chron (0.97 to 0.47 Ma) was determined to be > 100,000 yr whereas the upper Matuyama Chron was dominated by the 41,000-yr periodicity. These periodicities suggest that the sedimentation patterns within the upper Matuyama Chron (0.98-1.78 Ma) were influenced by the Milankovitch obliquity cycle and those within the latest Matuyama-Brunhes Chron (<0.98 Ma) by the eccentricity cycle. The Brunhes/Matuyama boundary therefore represents a major discontinuity. Periodicities observed within the lower Matuyama and the upper Gauss Chron did not correlate with any of the periodicities within the Milankovitch frequency bands.

(Table 1) K-Ar age and inert-gas-isotopes at DSDP Holes 68-501, 69-504B and 69-505B

Conventional K-Ar ages have been determined and inert-gas abundances have been measured on representative samples of altered rocks from Deep Sea Drilling Project Holes 501, 504B, and 505B in an attempt to correlate their degree of alteration with inert-gas and K-Ar data. Samples taken from the first 60 meters below the sediment/basalt interface give significantly higher ages than would be expected from the magnetic stratigraphy, though at greater depths the calculated ages are in broad agreement with the expected age. The inert gas ratios 20Ne/36Ar, 36Ar/84Kr, and 84Kr/130Xe also show a marked discontinuity at the 60-meter depth, and all these effects are interpreted as being a consequence of low-temperature alteration produced by burial metamorphism and by interaction with sea water (halmyrolysis).

La ruptura epistemológica de Bachelard a Balibar y Pêcheux

En el presente trabajo intentaremos analizar cierta serie o tradición de reflexiones sobre el conocimiento científico que lo caracterizan por su discontinuidad en relación al conocimiento ordinario o sentido común. El origen de esta serie puede localizarse en la obra de Gaston Bachelard y su peculiar estudio de los actos epistemológicos con los que se rompe con el pasado en una disciplina científica. Estos actos contrastan con lo que este autor califica como el "mito continuista" del empirismo. Esta posición será apropiada por Althusser y desarrollada por sus discípulos Balibar y Pêcheux. Intentaremos mostrar que el factor común de la discontinuidad no constituye ;una posición monolítica, sino que cabe reconocer, en las posiciones que consideramos, maneras diversas de entender la naturaleza de la misma. En este sentido, la revisión de las posiciones que Althusser efectuó en su "autocrítica" constituye un punto de observación privilegiado del abanico de alternativas que algunos de sus discípulos desarrollarían sobre bases diversas

River and Hillslope Response to Localized Uplift Along a Left Bend of the San Andreas Fault, Santa Cruz Mountains, CA

Studying landscape evolution of the Earthís surface is difficult because both tectonic forces and surface processes control its response to perturbation, and ultimately, its shape and form. Researchers often use numerical models to study erosional response to deformation because there are rarely natural settings in which we can evaluate both tectonic activity and topographic response over appropriate time scales (103-105 years). In certain locations, however, geologic conditions afford the unique opportunity to study the relationship between tectonics and topography. One such location is along the Dragonís Back Pressure Ridge in California, where the landscape moves over a structural discontinuity along the San Andreas Fault and landscape response to both the initiation and cessation of uplift can be observed. In their landmark study, Hilley and Arrowsmith (2008) found that geomorphic metrics such as channel steepness tracked uplift and that hillslope response lagged behind that of rivers. Ideal conditions such as uniform vegetation density and similar lithology allowed them to view each basin as a developmental stage of response to uplift only. Although this work represents a significant step forward in understanding landscape response to deformation, it remains unclear how these results translate to more geologically complex settings. In this study, I apply similar methodology to a left bend along the San Andreas Fault in the Santa Cruz Mountains, California. At this location, the landscape is translated through a zone of localized uplift caused by the bend, but vegetation, lithology, and structure vary. I examine the geomorphic response to uplift along the San Andreas Fault bend in order to determine whether predicted landscape patterns can be observed in a larger, more geologically complex setting than the Dragonís Back Pressure Ridge. I find that even with a larger-scale and a more complex setting, geomorphic metrics such as channel steepness index remain useful tools for evaluating landscape evolution through time. Steepness indices in selected streams of study record localized uplift caused by the restraining bend, while hillslope adjustment in the form of landsliding occurs over longer time scales. This project illustrates that it is possible to apply concepts of landscape evolution models to complex settings and is an important contribution to the body of geomorphological study.