Homotopic and Geometric Galois Theory (online meeting)

In his "Letter to Faltings'', Grothendieck lays the foundation of what will become part of his multi-faceted legacy to arithmetic geometry. This includes the following three branches discussed in the workshop: the arithmetic of Galois covers, the theory of motives and the theory of anabelian Galois representations. Their geometrical paradigms endow similar but complementary arithmetic insights for the study of the absolute Galois group $\mathrm{G}_{\mathbb{Q}}$ of the field of rational numbers that initially crystallized into a functorially group-theoretic unifying approach. Recent years have seen some new enrichments based on modern geometrical constructions - e.g. simplicial homotopy, Tannaka perversity, automorphic forms - that endow some higher considerations and outline new geometric principles. This workshop brought together an international panel of young and senior experts of arithmetic geometry who sketched the future desire paths of homotopic and geometric Galois theory

Spacecraft Systems & Navigation

This textbook is steered towards higher educational course entailed in Commercial Space Operations. This textbook will be covering in detail Orbital Satellites, and Spacecraft. These topics are discussed according to their application, design, and environment. The power system, shielding and communication systems are reviewed along with their missions, space, environment and limitations. Any vehicle, whether manned or unmanned, intended for space travel is a spacecraft. A spacecraft\u27s required systems and equipment depend on the information it will acquire and the tasks it will perform. Although their levels of sophistication vary widely, they re all subject to the harsh conditions of space. Depending on the missions that each spacecraft is designed to carry out, they can be broadly classed

A semi-empirical cellular automata model for wildfire monitoring from a geosynchronous space platform

The environmental and human impacts of wildfires have grown considerably in recent years due to an increase in their frequency and coverage. Effective wildfire management and suppression requires real-time data to locate fire fronts, model their propagation and assess the impact of biomass burning. Existing empirical wildfire models are based on fuel properties and meteorological data with inadequate spatial or temporal sampling. A geosynchronous space platform with the proposed set of high resolution infrared detectors provides a unique capability to monitor fires at improved spatial and temporal resolutions. The proposed system is feasible with state-of-the-art hardware and software for high sensitivity fire detection at saturation levels exceeding active flame temperatures. Ground resolutions of 100 meters per pixel can be achieved with repeat cycles less than one minute. Atmospheric transmission in the presence of clouds and smoke is considered. Modeling results suggest fire detection is possible through thin clouds and smoke. A semi-empirical cellular automata model based on theoretical elliptical spread shapes is introduced to predict wildfire propagation using detected fire front location and spread rate. Model accuracy compares favorably with real fire events and correlates within 2% of theoretical ellipse shapes. This propagation modeling approach could replace existing operational systems based on complex partial differential equations. The baseline geosynchronous fire detection system supplemented with a discrete-based propagation model has the potential to save lives and property in the otherwise uncertain and complex field of fire management

Forward and Inverse Modeling of GPS Multipath for Snow Monitoring

Snowpacks provide reservoirs of freshwater, storing solid precipitation and delaying runoff to be released later in the spring and summer when it is most needed. The goal of this dissertation is to develop the technique of GPS multipath reflectometry (GPS-MR) for ground-based measurement of snow depth. The phenomenon of multipath in GPS constitutes the reception of reflected signals in conjunction with the direct signal from a satellite. As these coherent direct and reflected signals go in and out of phase, signal-to-noise ratio (SNR) exhibits peaks and troughs that can be related to land surface characteristics. In contrast to other GPS reflectometry modes, in GPS-MR the poorly separated composite signal is collected utilizing a single antenna and correlated against a single replica. SNR observations derived from the newer L2-frequency civilian GPS signal (L2C) are used, as recorded by commercial off-the-shelf receivers and geodetic-quality antennas in existing GPS sites. I developed a forward/inverse approach for modeling GPS multipath present in SNR observations. The model here is unique in that it capitalizes on known information about the antenna response and the physics of surface scattering to aid in retrieving the unknown snow conditions in the antenna surroundings. This physically-based forward model is utilized to simulate the surface and antenna coupling. The statistically-rigorous inverse model is considered in two parts. Part I (theory) explains how the snow characteristics are parameterized; the observation/parameter sensitivity; inversion errors; and parameter uncertainty, which serves to indicate the sensing footprint where the reflection originates. Part II (practice) applies the multipath model to SNR observations and validates the resulting GPS retrievals against independent in situ measurements during a 1-3 year period in three different environments - grasslands, alpine, and forested. The assessment yields a correlation of 0.98 and an RMS error of 6-8 cm, with the GPS under-estimating in situ snow depth by approximately 15%. GPS daily site averages were found effective in mitigating random noise without unduly smoothing the sharp transitions as captured in new snow events. This work corroborates the readiness of quality-controlled GPS-MR for snow depth monitoring, reinforcing its maturity for operational usage

Tracking and data relay satellite system configuration and tradeoff study. Volume 5: TDRS spacecraft design, part 1

A dual spin stabilized TDR spacecraft design is presented for low data rate (LDR) and medium data rate (MDR) user spacecraft telecommunication relay service. The relay satellite provides command and data return channels for unmanned users together with duplex voice and data communication channels for manned user spacecraft. TDRS/ground links are in the Ku band. Command links are provided at UHF for LDR users and S band for MDR users. Voice communication channels are provided at UHF/VHF for LDR users and at S band for MDR users. The spacecraft is designed for launch on the Delta 2914 with system deployment planned for 1978. This volume contains a description of the overall TDR spacecraft configuration, a detailed description of the spacecraft subsystems, a reliability analysis, and a product effectiveness plan

Design study of Software-Implemented Fault-Tolerance (SIFT) computer

Software-implemented fault tolerant (SIFT) computer design for commercial aviation is reported. A SIFT design concept is addressed. Alternate strategies for physical implementation are considered. Hardware and software design correctness is addressed. System modeling and effectiveness evaluation are considered from a fault-tolerant point of view

Aeronautical Propulsion

Reports on the following technologies are included: engine design, exhaust gases, use of composites, bearings, and supersonic and hypersonic propulsion

Voyager spacecraft. Volume V - Alternate designs, subsystems considerations, appendix II Study report, phase IA

Stability and control, telecommunication system, solar array design, propellant feed system, and infrared model of Mars for Voyager projec

Integration of culture- and molecular-based water quality monitoring tools to protect human health

Monitoring and improving the microbiological quality and safety of surface waters used for various purposes, including drinking water abstraction and recreation is paramount as degradation may pose a serious risk to human health and cause significant economic losses as a result of the closure of beaches and shellfish harvesting areas. With the aim of providing new knowledge and tools with which to manage more effectively faecal contamination of water resources, this study focused on three goals: 1) determining the fate and suitability of new bioindicators for virus removal during wastewater treatment; 2) elucidating the levels and sources of faecal pollution in the River Tagus (Rio Tejo) using a blend of newly-developed and existing microbial source tracking (MST) markers; and 3) critically evaluating various pretreatments to distinguish between infectious and non-infectious viruses. To this end, raw and treated wastewater were collected and tested for the presence of traditional faecal indicator bacteria (FIB), and four viral bio-indicators (namely, somatic coliphages (SC), GB124 phages, human adenovirus (HAdV) and JC Polyomavirus (JCPyV)). In order to demonstrate whether the novel bio-indicators might be suitable indicators of risk to human health, Norovirus genogroup II (NoVGII) were also analysed, in parallel. FIB, SC and GB124 phages were analysed using standardised culture methods (membrane filtration and plaque assays) and HAdV, JCPyV and NoVGII were analysed using widely used molecular (qPCR) methods. Samples of river water were collected over a thirteen-month period and analysed for both non source-specific indicators of faecal contamination (Escherichia coli (EC), intestinal enterococci (IE), and SC) and source-specific contamination markers ((GB124 phages, HAdV) and four mitochondrial DNA markers (HMMit, CWMit, PigMit and PLMit)). EC, IE, SC and GB124 phages were detected by culture methods and HAdV and mitochondrial markers were detected by molecular (qPCR) methods. Furthermore, domestic animal markers (based on the detection of mitochondrial DNA) were also developed for dog and cat and tested during the catchment study. Finally, in order to determine accurately the level of risk to human health, heat-, chlorine-, and UV-inactivated Enterovirus and Mengovirus were subjected to PCR pre-treatments using enzymatic digestion and viability dyes, in order to determine infectivity. Detection of inactivated Mengovirus (MC0) was performed by RT-qPCR and detection of inactivated Enterovirus (EntV) was performed by both RT-qPCR and cell culture. The results demonstrated that the traditional bacterial indicators (FIB) were more effectively removed during wastewater treatment than GB124 phages, SC, HAdV and JCPyV, the removal levels of which were more similar to those of NoVGII. Spearman’s correlation showed that SC and GB124 phages correlated positively with NoVGII at a relatively high level and that HAdV and EC correlated positively at a moderate level. Discriminant analysis revealed that whilst no organism could predict the presence or absence of NoVGII in treated wastewater, GB124 phages in combination with other parameters did result in higher percentages of correct classification. GB124 phages plus HAdV appeared to be good candidates as alternative indicators of enteric virus removal during wastewater treatment. Results from the catchment study demonstrated that certain sites on the River Tagus are relatively highly impacted by faecal contamination (as indicated by EC, IE and SC concentrations). Moreover, the MST markers revealed that this contamination appears to be not only of human origin, but also originates from a range of other animal sources. The HMMit marker was the most prevalent and was found at the highest mean concentrations, followed by the CWMit marker. Two-way ANOVA revealed a correlation between concentrations of non source-specific indicators (and the CWMit marker) and season. Physico-chemical parameters, such as temperature and UV radiation, were found to be related to to levels of the CWMit, EC, IE, and SC. Interestingly, rainfall levels were found to be related to concentrations within the river of the PLMit marker and of the newly-developed dog and cat markers. Weak to no correlations were found between non source-specific indicators and the various MST markers, providing further evidence that these faecal indicators were unsuitable for determining the source(s) of contamination in this study. In contrast, the relatively high sensitivity and specificity of the mitochondrial DNA markers supported their use as appropriate markers of the origin of faecal contamination in this scenario. The results from the viral infectivity study demonstrated that results of ‘viability PCR’ (involving viability dyes) of chlorine- and UV-treated viruses did not correlate with those from cell culture assay. However, data from RNase-RT-qPCR from chlorine- and UV-inactivated viruses were consistent with the cell culture assay, achieving full PCR signal reduction in several instances. Heat treatment appeared to play an important role, since a significant reduction in the RT-qPCR signal was achieved. Different pre-treatments were able to achieve full removal of RT-qPCR signal for non-infectious heat-treated EntV and MC0. Therefore, enzymatic treatment may represent a rapid and inexpensive tool for discriminating between infectious and non-infectious viruses and as such should improve understanding of risks to human health. This research has demonstrated that the currently-used methodologies and approaches to assess the potential human health impact of wastewater discharges to environmental waters are limited in their ability to predict the prevalence of important agents of human waterborne disease. Furthermore, these findings provide evidence to support the development and application of alternative and potentially more effective approaches, which could better protect human health in the future

Designing a robot to evaluate group formations

Robots are making their way in environments inhabited by people. Whether in domestic or public crowded environments, robots should take into consideration social norms and behaviors in order to become a social robot. This dissertation focuses on the problem of how to develop a robotic platform in order to validate human-robot interaction experiences in realistic environments. More specifically, we are concerned with social interactions in human-robot groups in public scenarios, where a variety of people can converge. Our final goal is the develop of a social robot based on certain theories of group behavior and the use of space, known as spatial relationships. The intermediate goals are related with the design and development of the experiences in the wild: as minor changes as possible in the scenario, definition of social tasks, gradual development of a robotic platform as transparent as possible from the robotic side. Initially, this research introduces several preliminary studies of human-robot interaction (HRI) with the PAL Robotics’ REEM robot at the CosmoCaixa Science Museum in Barcelona. Based on certain theories about the use of space as a form of social communication or interaction, the task under study with the commercial robot is as a museum guide, both when the group was in motion (\ie when it was being guided) as well as a group in a static place. Moreover, a second HRI study with REEM robot accomplishing the task of a teacher's assistant was carried out to analyze the perception of the robot's social presence and identity. Likewise, the development of a robotic platform, known as MASHI, for the study of HRI is presented. Based on the service to be completed by the robot, improvements in the experimental robotic platform (structure, morphology, head, face, arms) were carried out in continuous cycles following the development of HRI experiences. This structure should be hold as simple as possible in order to make it `transparent' in the social HRI study. Next, the field study of human-robot social interaction with the MASHI robot with the role of exhibition guide in a cultural center is presented. Based on direct observation techniques, a study is made of the different spatial relationships that are generated when a robot interacts with a person or groups of people. Finally, a novel approach to represent the spatial relationships of HRI in a qualitative way is introduced for future experiences. In this concluding study, we analyze different spatial arrangements generated in a social scenario with a robot within the guide role. As a main conclusion, it can be stated that people follow social norms, in the form of spatial relationships, when interacting with a robot that provide a social service in a public space. Children, however, recurrently challenge these social norms, probably because they are constantly learning about the norms that regulate our coexistence. Spatial relationships are clearly reinforced when the role assigned to the robot is more explicit and understood by people. Spatial relationships can be affected by the characteristics of the environment, either by the available space or by the elements arranged in it, as well as by the number of people who inhabit it. Overall, this dissertation points out that the provided service, and its understanding from the user’s side, is more important that the robotic skills of the robotic platform in order to improve user experiences in public environments.Los robots se abren paso en entornos habitados por personas. Ya sea en entornos domésticos o públicos, los robots deben tener en cuenta ciertas normas y comportamientos sociales para convertirse en un robot social. Esta disertación se centra en el problema de cómo desarrollar una plataforma robótica para validar experiencias de interacción humano-robot en entornos realistas. Más específicamente, nos preocupamos por las interacciones sociales en grupos humano-robot en escenarios públicos, donde una gran variedad de personas puede converger. Nuestro objetivo final es el desarrollo de un robot social basado en ciertas teorías de comportamiento grupal y el uso del espacio, conocidas como relaciones espaciales. Los objetivos intermedios están relacionados con el diseño y desarrollo de las experiencias `en la naturaleza': cambios mínimos como sea posible en el escenario, definición de tareas sociales, desarrollo gradual de una plataforma robótica lo más transparente posible desde el lado robótico. Inicialmente, esta investigación presenta varios estudios preliminares de interacción humano-robot (HRI) con el robot REEM de PAL Robotics en el Museo de Ciencias CosmoCaixa de Barcelona. Basado en ciertas teorías sobre el uso del espacio como una forma de comunicación o interacción social, la tarea en este estudio con el robot comercial es como guía de museo, tanto cuando el grupo estaba en movimiento (es decir, cuando estaba siendo guiado) como cuando el grupo estaba en un lugar estático. Además, se llevó a cabo un segundo estudio de HRI con un robot REEM que realizaba la tarea de un asistente de profesor para analizar la percepción de la presencia e identidad social del robot. Asimismo, se presenta el desarrollo de una plataforma robótica, conocida como MASHI, para el estudio de la HRI. En función del servicio que debe completar el robot, las mejoras en la plataforma robótica experimental (estructura, morfología, cabeza, cara, brazos) se llevaron a cabo en ciclos continuos siguiendo el desarrollo de las experiencias de HRI. Esta estructura debe mantenerse lo más simple posible para que sea 'transparente' en el estudio de HRI social. A continuación, se presenta el estudio de campo de la interacción social humano-robot con el robot MASHI con el papel de guía de exposición en un centro cultural. Con base en técnicas de observación directa, se realiza un estudio de las diferentes relaciones espaciales que se generan cuando un robot interactúa con una persona o grupos de personas. Finalmente, se introduce un enfoque novedoso para representar las relaciones espaciales de la HRI de forma cualitativa para las experiencias futuras. En este estudio final, analizamos diferentes arreglos espaciales generados en un escenario social con un robot con el rol de guía. Como conclusión principal, se puede afirmar que las personas siguen normas sociales, en forma de relaciones espaciales, cuando interactúan con un robot que brinda un servicio social en un espacio público. Los niños, sin embargo, desafían recurrentemente estas normas sociales, probablemente porque están aprendiendo constantemente sobre las normas que regulan nuestra convivencia. Las relaciones espaciales se refuerzan claramente cuando el rol asignado al robot es más explícito y entendido por las personas. Las relaciones espaciales pueden verse afectadas por las características del entorno, ya sea por el espacio disponible o por los elementos dispuestos en él, así como por el número de personas que lo habitan. En general, esta disertación señala que el servicio prestado, y su comprensión del lado del usuario, es más importante que las habilidades robóticas de la plataforma robótica con el fin de mejorar las experiencias del usuario en entornos público