Les travaux de recherches sur la commande, le diagnostic et la tolérance aux défauts appliqués aux drones deviennent de plus en plus populaires. Il est judicieux de concevoir des lois de commande qui garantissent la stabilité et les performances du drone, non seulement dans le cas nominal, mais également en présence de fortes perturbations et de défauts.Dans cette thèse, un nouvel algorithme bio-inspiré adapté pour la recherche de solutions dans des problèmes d’optimisation est développé. Cet algorithme est utilisé pour trouver les gains des différents contrôleurs conçus pour les drones. La commande par mode glissant est utilisée pour développer deux contrôleurs passifs tolérants aux défauts pour les quadrirotors: un contrôleur par mode glissant augmentée avec un intégrateur, et un contrôleur par mode glissant implémenté en cascade. Parce que les commandes passives ont une robustesse réduite, une commande active par mode glissant est développée. Pour traiter les défauts extrêmes, un contrôleur d’urgence basé sur la conversion du quadrirotor en trirotor est développé. Les commandes actives, passives, et le contrôleur d’urgences sont ensuite intégrés pour former un contrôleur tolérant aux défauts capable de gérer un grand nombre de défaillances tout en garantissant les ressources actionneur et en limitant la charge de calcul du processeur. Finalement, des contrôleurs tolérants aux défauts, actifs et passifs, basés sur des méthodes par mode glissant du premier et deuxième ordre sont développées pour les octorotors. La commande active utilise des méthodes d’allocation de contrôles pour redistribuer les efforts sur les actionneurs sains, réduisant ainsi l’effet du défaut. / Unmanned Aerial Vehicles (UAV) are more and more popular for their civil and military applications. Classical control laws usually show weaknesses in the presence of parameter uncertainties, environmental disturbances, and actuator and sensor faults. Therefore, it is judicious to design a control law capable of stabilizing the UAV not only in the fault-free nominal cases, but also in the presence of disturbances and faults. In this thesis, a new bio-inspired search algorithm called Ecological Systems Algorithm (ESA) suitable for engineering optimization problems is developed. The algorithm is used over the thesis to find optimal gains for the fault tolerant controllers. Sliding Mode Control theory is used to develop two Passive Fault Tolerant Controllers for quadrotor UAVs: Regular and Cascaded SMC. Because Passive Controllers handle a few numbers of faults, an Active Sliding Mode Fault Tolerant Controller using Kalman Filter is developed. To overcome severe faults and failures, an emergency controller based on the Quadrotor-to-Trirotor conversion maneuver is developed. The Controllers developed so far (Passive, Active, and emergency controllers) are then integrated to form the Integrated Fault Tolerant Controller (IFTC). The IFTC is a powerful controller that is able to handle a wide number of faults, and save actuator resources as well as processor computational effort. Finally, Passive and Active Fault Tolerant Controllers are designed for octorotor UAVs based on First Order and Second Order Sliding Mode Control. The AFTC uses Dynamic and Pseudo-Inverse Control Allocation methods to redistribute the control effort among healthy actuators reducing the effect of fault.

This thesis examines the foreign policy of the 44th President of the United States of America, Barack Obama. A significant theme of Barack Obama's candidacy for presidency was "change"; more specifically change in policy from previous administration. Therefore, the thesis looks at the changes brought about by President Obama once he was elected. First, we look at foreign policy of the United States under President George W. Bush, then we look at foreign policy-related assertions of Barack Obama during his candidacy, and lastly we look at the actual policies of the new administration, with particular focus on the wars in Iraq and Afghanistan, drones and extrajudicial killing, Guantanamo detention facility and extraordinary rendition, and NSA surveillance.

Unmanned Aerial Vehicle (UAV), also called drones, are used for Search And Rescue (SAR) missions, mainly in the form of a pilot manoeuvring a single drone. However, the increase in labour to cover larger areas quickly would result in a very high cost and time spent per rescue operation. Therefore, there is a need for an easy to use, low-cost, and highly autonomous swarm of drones for SAR missions where the detection and rescue times are kept to a minimum. In this thesis, a Subsumption-based architecture is proposed, which combines multiple behaviours to create more complex behaviours. An investigation of (1) what are the critical aspects of controlling a swarm of drones, (2) how can a combination of different behavioural algorithms increase the performance of a swarm of drones, and (3) what benchmarks are necessary when evaluating the fitness of the behavioural algorithms. The proposed architecture was simulated in AirSim using the SimpleFlight flight controller through experiments that evaluated the individual layers and missions that simulated real-life scenarios. The results validate the modularity and reliability of the architecture, where the architecture has the potential for improvements in future iterations. For the search area of 400×400meters, the swarm consistently produced an average area coverage of at least 99.917% and found all the missing people in all missions, with the slowest average being 563 seconds. Compared to related work, the result produced similar or better times when scaled to the same proportions and higher area coverage. As comparisons of results in SAR missions can be difficult, the introduction of Active time can serve as a benchmark for others in future swarm performance measurements.

No description available.

<p dir="ltr">This dissertation presents the design, development, and testing environment of a low-cost, self-built ground based Counter Unmanned Aerial or Aircraft Vehicle (CUAV) system aimed at providing effective aerial security solutions in resource-limited environments. The kinetic CUAV technique was selected and identified for the current study as it is the most feasible, low-cost and reusable mitigation path as last-resort defense. Utilizing commonly available materials, including parts from online retailers and hardware stores, and incorporating a self-made pneumatic system with a reusable 3D-printed projectile and interchangeable parts design. This study explores the feasibility of cost-effective drone defense and introduces a short-range accuracy metric to evaluate the system’s trajectory behavior. Through rigorous indoor testing in Purdue University Hangar 4, the research evaluates the system's performance in terms of projectile height, range, and accuracy under various environmental conditions. A 90 degrees field of view of pneumatic launcher was tested with a small error margin comparison table to highlight on areas for potential technical refinement. TPU filament was found to be the best material for this study, with 10% infill, printing temperature in 225°C (437°F), and 70 mm/s printing speed settings for the 3D-printed projectile (4.16a). These findings in Figures 4.10, 4.11, 4.12, 4.13 will significantly advance the research of low-cost drone defense technologies by providing empirical evidence on material and design choices that will impact the system performance. Findings indicate that the system’s performance is affected by the climate temperatures, which influences its consistency in different settings. This offers practical implications for enhancing security measures against unauthorized drones using similar technology. The study fills a significant gap in current drone defense technologies with kinetic apprehension by proving that effective solutions can be both affordable and accessible. This work not only contributes to the advancement of counter drone technology but also encourages ongoing design innovation in the field, paving the way for further research and development into scalable and adaptable drone defense systems.</p>

<p>This dissertation examines the impact of active shooters upon patrons attending large outdoor events. There has been a spike in shooters targeting densely populated spaces in recent years, to include open-air venues. The 2019 Gilroy Garlic Festival was selected for modeling replication using AnyLogic software to test various experiments designed to reduce casualties in the event of an active shooter situation. Through achievement of validation to produce identical outcomes of the real-world Gilroy Garlic Festival shooting, the researcher established a reliable foundational model for experimental purposes. This active shooter research project identifies the need for rapid response efforts to neutralize the shooter(s) as quickly as possible to minimize casualties. Key findings include the importance of armed officers patrolling event grounds to reduce response time, the need for adequate exits during emergency evacuations, incorporation of modern technology to identify the shooter’s location, and applicability of a 1:548 police to patron ratio.</p>

Sjöräddning i Sverige sker genom samverkan mellan statliga verksamheter, kommuner och frivilligorganisationer för ett gemensamt mål att rädda personer som råkat i sjönöd. Tid är ofta en kritisk faktor i räddningsuppdragen men ett snabbt och oplanerat utryck riskerar samtidigt att sätta räddningsaktörerna själva i farozonen. Utvecklingen av obemannade autonoma farkoster för SAR (eng. Search And Rescue) ses som en lösning på behovet att kunna snabbt skicka hjälp till samt få ögon på incidentplatsen utan att försätta räddningsaktörerna för onödig risk. Nuvarande kommunikationssystem inom svensk sjöräddning kan dock inte hantera annan typ av information än muntlig varav räddningsaktörer endast känner till riktlinjer för hantering av muntlig information. Med ett framtida införande av autonoma farkoster kommer dock fler informationstyper att behöva hanteras i sjöräddningar varav oklarheten om vilka informationstyper autonoma farkoster samlar in och vilka datahanteringskrav som finns är problematiskt. Oklarhet om informationstyperna och deras datahanteringskrav är vidare problematiskt för utvecklingen och implementeringen av autonoma farkoster då risken finns att farkoster och tekniker utvecklas men inte får användas för att de inte är anpassade efter lagkraven på hantering av olika datatyper. I denna studie undersöks därför vilka informationstyper som autonoma farkoster kan samla in vid sjöräddning. Detta för att komma fram till vilka riktlinjer för datahantering som gäller vid sjöräddning med autonoma farkoster. Studien undersöker också vilka informationstyper som är kritiska för en SAR-sjöräddningssamverkan samt vilka informationsdelningsutmaningar som finns i dagens sjöräddning. Studien genomfördes i form av en kvalitativ fallstudie och har tillämpat ett socio-tekniskt systemperspektiv för att bättre se till helheten och besvara frågeställningarna. Resultatet av denna studie visar att autonoma farkoster kan samla in information om sin omgivning, vilket utgör grunden för att skapa en medvetenhet om situationen som är kritiskt för SAR-operationer, och kan även samla in information om sitt eget tillstånd. De lagverk som identifierats utgöra de huvudsakliga restriktionerna är kamerabevakningslagen, lagen för skydd av geografisk information, offentlighets- och sekretesslagen, GDPR och dataskyddslagen. Dessa lagverk innehåller riktlinjer för delning av information och personuppgiftsbehandling i SAR-sjöräddning. Kunskapsbidrag studien har genererat inkluderar bland annat identifiering av datatyper som kan samlas in av autonoma farkoster i en SAR-sjöräddning, och sannolikt andra typer av räddningsinsatser, och delning och hanteringskraven på de datatyperna i räddningsinsatser och därmed kunskap om vilka datatyper som är mest reglerade. Vidare kunskapsbidrag är kunskap om vilka informationstyper som är mest kritiska för SAR-sjöräddningar, och därför bör prioriteras att samlas in och delas, och identifieringen av utmaningar för informationsdelning mellan statliga verksamheter och frivilligorganisationer. / Maritime rescue in Sweden is performed through a cooperation between government agencies, municipalities and non-governmental organisations (NGOs) with the common goal of saving people in distress. Time is often a critical factor in the rescue missions but a fast and unplanned response may at the same time put the rescue workers in danger. The development of unmanned autonomous vehicles for SAR is seen as a solution to the need of being able to quickly sendhelp as well as get eyes on the scene of the incident without exposing the rescue workers for unnecessary risks. However, the current communications systems in Swedish maritime rescue are unable to handle any other type of information except verbal, meaning that rescue workers only know guidelines for handling verbal information. However, with a future implementation of autonomous vehicles, there will be a need to handle more information types in maritime rescue whereas the uncertainty regarding what kind of information autonomous vehicles collect and which data management requirements exist is problematic. The uncertainty about the information types and their data management requirements is also problematic for the development and implementation of autonomous vehicles as there is a risk that vehicles and technologies are developed but not allowed to be used because they are not adapted to the legal requirements on management of the different types of data. Therefore, in this study I examine what information types that autonomous vehicles can collect in a maritime rescue to find out what guidelines for data management that applies during a maritime rescue with autonomous vehicles. The study also examines what kind of information’s are critical for a SAR maritime rescue cooperation as well as what information sharing challenges exist in current maritime rescue. The study was performed as a qualitative case study and has used a socio-technical systems perspective so as to better see the overall picture and answer the research questions. The result shows that autonomous vehicles can collect information about their surroundings, which is the foundation for establishing situation awareness that is critical for SAR-operations, and that they can collect information about their own status. The main laws and regulations that have been identified as constituting the main restrictions are (translated from Swedish) the law of camera surveillance, the law for protection of geographical information, the public access to information and secrecy act, the GDPR and the data protection act. These contains guidelines for sharing information and the processing of personal data in SAR maritime rescue. The knowledge contributions of this study includes among others the identification of datatypes that can be collected by autonomous vehicles in SAR maritime rescue, and probably other types of rescue operations, and the sharing and management requirements on those datatypes in rescue operations and thus knowledge of what datatypes that are the most restricted. Further knowledge contributions is knowledge about which information types that are the most critical for SAR maritime rescue and thus should be prioritised for collection and sharing as well as the identification of challenges for information sharing between government agencies and NGOs.

During the last century, various countries' armed forces have used unmanned aerial vehicles, commonly known as drones. In recent years, strives have been made to develop small commercial drones that have allowed the general public to afford and use them for recreational purposes. The availability of drones has led to immoral applications of the technology. Such applications need to be faced with anti-measures and effective detection methods. Therefore, this thesis aims to develop a mobile reconnaissance robot that can detect commercial drones with radar. It describes integrating radar sensors with single-board computers to detect and localise air-bound objects. The finished product aims to be used for educational and exhibition purposes at the Swedish Armed Forces technical school to increase awareness of the technology. / <p>Försvarsmaktens tekniska skola i Halmstad var intressenter för uppsatsen.</p>

The advent of unoccupied aerial systems (UAS) as disruptive technology has a lasting impact on remote sensing, geophysics and most geosciences. Small, lightweight, and low-cost UAS enable researchers and surveyors to acquire earth observation data in higher spatial and spectral resolution as compared to airborne and satellite data. UAS-based applications range from rapid topographic mapping using photogrammetric techniques to hyperspectral and geophysical measurements of surface and subsurface geology. UAS surveys contribute to identifying metal deposits, monitoring of mine sites and can reveal arising environmental issues associated with mining. Further, affordable UAS technology will boost exploration data availability and expertise in the global south. This thesis investigates the application of UAS-based multi-sensor data for mineral exploration, in particular the integration of hyperspectral imagers, magnetometers and digital cameras (covering the visible red, green, blue light spectrum). UAS-based research is maturing, however the aforementioned methods are not unified effectively. RGB-based photogrammetry is used to investigate topography and surface texture. Image spectrometers measure mineral-specific surface signatures. Magnetometers detect geomagnetic field changes caused by magnetic minerals at surface and depth. The integration of such UAS sensor-based methods in this thesis augments exploration potential with non-invasive, high-resolution, safe, rapid and practical survey methods. UAS-based surveying acquired, processed and integrated data from three distinct test sites. The sites are located in Finland (Fe-Ti-V at Otanmäki; apatite at Siilinjärvi) and Greenland (Ni-Cu-PGE at Qullissat, Disko Island) and were chosen as geologically diverse areas in subarctic to arctic environments. Restricted accessibility, unfavourable atmospheric conditions, dark rocks, debris and vegetation cover and low solar illumination were common features. While the topography in Finland was moderately flat, a steep landscape challenged the Greenland field work. These restraints meant that acquisitions varied from site to site and how data was integrated and interpreted is dependent on the commodity of interest. Iron-based spectral absorption and magnetic mineral response were detected using hyperspectral and magnetic surveying in Otanmäki. Multi-sensor-based image feature detection and classification combined with magnetic forward modelling enabled seamless geologic mapping in Siilinjärvi. Detailed magnetic inversion and multispectral photogrammetry led to the construction of a comprehensive 3D model of magmatic exploration targets in Greenland. Ground truth at different intensity was employed to verify UAS-based data interpretations during all case studies. Laboratory analysis was applied when deemed necessary to acquire geologic-mineralogic validation (e.g., X-ray diffraction and optical microscopy for mineral identification to establish lithologic domains, magnetic susceptibility measurements for subsurface modelling), for example for trace amounts of magnetite in carbonatite (Siilinjärvi) and native iron occurrence in basalt (Qullissat). Technical achievements were the integration of a multicopter-based prototype fluxgate-magnetometer data from different survey altitudes with ground truth, and a feasibility study with a high-speed multispectral image system for fixed-wing UAS. The employed case studies transfer the experiences made towards general recommendations for UAS application-based multi-sensor integration. This thesis highlights the feasibility of UAS-based surveying at target scale (1–50 km2) and solidifies versatile survey approaches for multi-sensor integration. / Ziel dieser Arbeit war es, das Potenzial einer Drohnen-basierten Mineralexploration mit Multisensor-Datenintegration unter Verwendung optisch-spektroskopischer und magnetischer Methoden zu untersuchen, um u. a. übertragbare Arbeitsabläufe zu erstellen. Die untersuchte Literatur legt nahe, dass Drohnen-basierte Bildspektroskopie und magnetische Sensoren ein ausgereiftes technologisches Niveau erreichen und erhebliches Potenzial für die Anwendungsentwicklung bieten, aber es noch keine ausreichende Synergie von hyperspektralen und magnetischen Methoden gibt. Diese Arbeit umfasste drei Fallstudien, bei denen die Drohnengestützte Vermessung von geologischen Zielen in subarktischen bis arktischen Regionen angewendet wurde. Eine Kombination von Drohnen-Technologie mit RGB, Multi- und Hyperspektralkameras und Magnetometern ist vorteilhaft und schuf die Grundlage für eine integrierte Modellierung in den Fallstudien. Die Untersuchungen wurden in einem Gelände mit flacher und zerklüfteter Topografie, verdeckten Zielen und unter oft schlechten Lichtverhältnissen durchgeführt. Unter diesen Bedingungen war es das Ziel, die Anwendbarkeit von Drohnen-basierten Multisensordaten in verschiedenen Explorationsumgebungen zu bewerten. Hochauflösende Oberflächenbilder und Untergrundinformationen aus der Magnetik wurden fusioniert und gemeinsam interpretiert, dabei war eine selektive Gesteinsprobennahme und Analyse ein wesentlicher Bestandteil dieser Arbeit und für die Validierung notwendig. Für eine Eisenerzlagerstätte wurde eine einfache Ressourcenschätzung durchgeführt, indem Magnetik, bildspektroskopisch-basierte Indizes und 2D-Strukturinterpretation integriert wurden. Fotogrammetrische 3D-Modellierung, magnetisches forward-modelling und hyperspektrale Klassifizierungen wurden für eine Karbonatit-Intrusion angewendet, um einen kompletten Explorationsabschnitt zu erfassen. Eine Vektorinversion von magnetischen Daten von Disko Island, Grönland, wurden genutzt, um großräumige 3D-Modelle von undifferenzierten Erdrutschblöcken zu erstellen, sowie diese zu identifizieren und zu vermessen. Die integrierte spektrale und magnetische Kartierung in komplexen Gebieten verbesserte die Erkennungsrate und räumliche Auflösung von Erkundungszielen und reduzierte Zeit, Aufwand und benötigtes Probenmaterial für eine komplexe Interpretation. Der Prototyp einer Multispektralkamera, gebaut für eine Starrflügler-Drohne für die schnelle Vermessung, wurde entwickelt, erfolgreich getestet und zum Teil ausgewertet. Die vorgelegte Arbeit zeigt die Vorteile und Potenziale von Multisensor-Drohnen als praktisches, leichtes, sicheres, schnelles und komfortabel einsetzbares geowissenschaftliches Werkzeug, um digitale Modelle für präzise Rohstofferkundung und geologische Kartierung zu erstellen.

[ES] Esta tesis investiga las oportunidades, desafíos y limitaciones para la investigación en el campo de la ecología vegetal, en el contexto de los acantilados mediterráneos. En concreto, las especies casmofiticas, cuyos hábitats naturales se caracterizan por su acusada pendiente. Las laderas de las montañas de piedra caliza en la proximidad del mar, en la parte central y occidental del área mediterránea se consideran objetos de estudio. Los estudios se llevaron a cabo en los cinturones costeros de montaña de las costas del noroeste de Sicilia y la costa diánica en la Comunidad Valenciana. El primer capítulo, titulado "The complexity of environmental factors: cliff microclimate", investiga la variabilidad del microclima del acantilado en tres áreas diferentes en Sicilia y España, analizando las condiciones ambientales creadas por el acantilado en una escala muy estrecha. Se recopilaron seis conjuntos de datos independientes y comparables que recogen las principales variables meteorológicas a lo largo de un período total de 18 meses. La gama resultante de condiciones ambientales se compara por pares a lo largo de dos gradientes ambientales principales: la orientación del acantilado Norte/Sur y la proximidad al mar. Además, los rasgos foliares intraespecíficos se utilizan para estudiar la variación en la respuesta funcional de las plantas que viven en las orientaciónes opuestas en una misma área de investigación. La variación resultante se correlaciona con la influencia de las condiciones microclimáticas creadas por la pendiente y el aspecto en los rasgos de la planta antes mencionados. El segundo capítulo, titulado "Compositional data and analyses of areas and plant communities in the coastal cliffs of the Valencian Community (Spain)", presenta una ordenación de los sitios de estudio y de las especies vegetales que habitan en las zonas de acantilados del cinturón montañoso a lo largo de las costas de la región diánica en el este de España. El estudio reveló correlaciones significativas entre las unidades de vegetación y los sitios con referencia a la amplia orientación geográfica Norte/Sur. Sin embargo, fue poco informativo con respecto a revelar las principales diferencias observadas en la estructura del conjunto de plantas relacionadas con laa variaciones microtopográficas registradas en el conjunto de datos. En el tercer capítulo, titulado "UAV (drone) surveys for the study of plant- microtopography relationships and for the conservation of rare species", se describe la metodología propuesta para investigar entornos verticales poco accesibles. También se analizaron los desafíos y las oportunidades de la investigación ecológica vegetal en estas áreas tipicamente inaccesibles. Un primer conjunto de datos comprende un censo visual parcial y total de dos especies endémicas de acantilados estrechos en las áreas de estudio españolas e italianas. Mediante el uso de la fotogrametría aérea de corto alcance y el modelado 3D, fue posible estudiar los efectos de la micro topografía en la segregación de nichos, tanto a nivel de comunidad como de especie. Se utilizaron métodos de ordenación para correlacionar las especies endémicas seleccionadas y conjuntos de plantas con factores ambientales como el aspecto local y global, la pendiente y la distancia desde los bordes de los acantilados. En el cuarto capítulo, titulado "Distribution, ecology, conservation status and phylogeography of Pseudoscabiosa limonifolia, a paleo-endemic chasmophytic species from Sicily (Italy)", se analiza en detalle la estructura filogeográfica de una especie endémica de acantilados, Pseudoscabiosa limonifolia (Caprifoliaceae, subfamilia Dipsacaceae), también considerando las relaciones filogeográficas con sus taxones más próximos. Además, su distribución total se determinó mediante observaciones de campo, caracterizando su hábitat y evaluando su estado de conservación como Vulnerable de acuerdo con las / [CA] Aquesta tesi va investigar les oportunitats, reptes i limitacions per a la investigació en el camp de l'ecologia vegetal, en el context dels penya-segats mediterranis. En concret, les espècies casmofitiques, amb hàbitats naturals que es caracteritzen pel seu acusat pendent. Les vessants de les muntanyes de pedra calcària en la proximitat del mar, a la part central i occidental de l'àrea mediterrània són considerats objectes d'estudi. Els estudis es portaren a terme als cinturons costers de muntanya de les costes del nord de Sicília i la costa diànica a la Comunitat Valenciana. El primer capítol, titulat "The complexity of environmental factors: cliff microclimate", investiga la variabilitat del microclima del penya-segat en tres àrees diferents de Sicília i Espanya, analitzant les condicions ambientals creades pel penya-segat a una escala molt estreta. Es recopilen sis conjunts de dades independents i comparables que reconeixen les principals variables meteorològiques a llarg termini durant un període total de 18 mesos. Les dades resultants de les condicions ambientals es comparen per parells al llarg de dos gradients ambientals principals: l'orientació del penya-segat Nord/Sud i la proximitat a la mar. A més, els trests foliars intraespecífics s'utilitzen per estudiar la variació en la resposta funcional de les plantes que habiten orientacions oposades dins d'un àrea d' investigació. La variació resultant es correlaciona amb la influència de les condicions microclimàtiques creades pel vessant i els aspectos funcionals dels trets vegetals esmentats. El segon capítol, titulat "Compositional data and analyses of areas and plant communities in the coastal cliffs of the Valencian Community (Spain)", presenta una ordenació dels llocs d'estudi i de les espècies de plantes que habiten a les zones de penya- segats del cinturó de muntanya al llarg de les costes de la regió diànica de España. L'estudi va a revelar correlacions significatives entre les unitats de vegetació i els llocs amb referència a l'amplias orientació geogràfica Nord/Sud. No obstant aixó, va ser poc informatiu per poder revelar les diferències observades en l'estructura del conjunt de plantes relacionades amb les variacions microtopogràfiques registrades al conjunt de dades Al tercer capítol, titulat "UAV (drone) surveys for the study of plant-microtopography relationships and for the conservation of rare species", es descriu la metodologia proposada per a investigar entorns verticals poc accessibles. També es van analitzar els reptes i les oportunitats de la investigació ecològica vegetal en aquestes àrees normalment inaccesibles. Un primer conjunt de dades inclou el cens visual parcial i el total de dues espècies endèmiques de penya-segats a les àrees d'estudi espanyoles i italianes. Mitjançant la fotogrametria aèrea a curt abast i el modelat 3D, va ser possible estudiar els efectes de la microtopografia en la segregació de nínxols, tant a nivell comunitari com d'espècies. Es van utilitzar mètodes d'ordenació per a correlacionar les espècies endèmiques seleccionades i conjunts vegetals sencers amb factors ambientals com ara l'aspecte local i global, el pendent i la distància de les vores dels penya-segats. En el quart capítol, titulat "Distribution, ecology, conservation status and phylogeography of Pseudoscabiosa limonifolia, a paleo-endemic chasmophytic species from Sicily (Italy)", que s'analitza en detall l'estructura filogeográfica d'una espècie endèmica de penya-segats, Pseudoscabiosa limonifolia (Caprifoliaceae, subfamilia Dipsacaceae), considerant tambè les relacions filogeogràfiques amb els seus taxons més propers. A més, la seva distribució total es va determinar mitjançant observacions de camp, caracteritzant el seu hàbitat i avaluant el seu estat de conservació com a Vulnerable, d'acord amb les directrius de la llista roja de la UICN. / [EN] This thesis investigated opportunities, challenges and limitations for plant ecological research in the context of Mediterranean cliffs. In particular, chasmophytic species, whose natural habitats are very steep, limestone mountain slopes in the proximity of the sea, in the Central and Western part of the Mediterranean area are considered as study objects. Studies were carried out in the coastal mountain belts of both North-western Sicily and Dianic coasts in the Valencian Community (Spain). The first chapter, entitled "The complexity of environmental factors: cliff microclimate", investigates the variability of cliff microclimate in three different areas in Sicily and Spain, analysing the environmental conditions created by the cliff at very fine scale. Six independent and comparable datasets including the main meteorological variables were compiled in a total period of 18 months. The resulting spectra of environmental conditions are compared pairwise along two key environmental gradients: North/South cliff orientation and proximity to the sea. Intraspecific leaf traits are used in order to investigate variations in the functional response of plants living on opposite orientations. The resulting variation is then correlated with the influence of microclimatic conditions created by slope and functional aspects of the aforementioned plant traits. The second chapter, entitled "Compositional data and analyses of areas and plant communities in the coastal cliffs of the Valencian Community (Spain)", presents an ordination of the study sites and of the plant species inhabiting the cliff zones of the mountain belt along the coasts of the Dianic region in Eastern Spain. The study revealed significant correlations between the vegetation units and the sites with reference to the broad North/South geographical orientation. However, it was poorly informative in respect to reveal the major differences observed in the structure of the plant assemblage related to the micro- topographic variations recorded in the dataset. In the third chapter, entitled "UAV (drone) surveys for the study of plant- microtopography relationships and for the conservation of rare species", a proposed survey methodology for investigating inaccessible vertical environments is described. Challenges and opportunities of plant ecological research in these typically inaccessible areas were also analysed. A first set of data is comprised of partial and total visual census of two narrow endemic cliff species in the Spanish and Italian study areas. Through the use of aerial close- range photogrammetry and 3D modelling, it was possible to study the effects of micro-topography on niche segregation, both at community and species level. Ordination methods were used to correlate selected endemic species and entire plant assemblages to environmental factors such as local and global aspect, slope and distance from cliff edges. The fourth chapter, entitled "Distribution, ecology, conservation status and phylogeography of Pseudoscabiosa limonifolia, a paleo-endemic chasmophytic species from Sicily (Italy)", is addressed to analyse in details the phylogeographic structure of a cliff narrow endemic species, Pseudoscabiosa limonifolia (VAHL) DEVESA (Caprifoliaceae, subfamily Dipsacaceae), also taking in consideration its closest sister taxa. Furthermore, its total distribution was determined by field surveys, characterizing its habitat, and assessing its conservation status as Vulnerable according to IUCN red list guidelines. / De Simone, L. (2020). Ecological aspects of plants inhabiting Mediterranean cliffs. Challenges and prospects of life in vertical environments [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/159877