Hand-eye calibration made easy through a closed-form two-stage method

© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksAn analysis of the existing hand-eye calibration methods reveals that most of them are far from trivial. And, what is worse, their intrinsic complexity makes it difficult to elucidate under which circumstances they fail to provide an accurate solution. Thus, although it might seem that hand-eye calibration problem is uninspiring because it is assumed to be well-solved, we show in this paper that there was still room for improvement, both in terms of simplicity and robustness. After reviewing the most representative methods, we analyze the situations in which they fail, and we introduce a simpler closed-form alternative that accurately solves the problem in all the identified critical circumstances. Its performance is evaluated using simulated and real experimental data.Peer ReviewedPostprint (author's final draft

Multi-task multiple kernel learning reveals relevant frequency bands for critical areas localization in focal epilepsy

The localization of epileptic zone in pharmacoresistant focal epileptic patients is a daunting task, typically performed by medical experts through visual inspection over highly sampled neural recordings. For a finer localization of the epileptogenic areas and a deeper understanding of the pathology both the identification of pathogenical biomarkers and the automatic characterization of epileptic signals are desirable. In this work we present a data integration learning method based on multi-level representation of stereo-electroencephalography recordings and multiple kernel learning. To the best of our knowledge, this is the first attempt to tackle both aspects simultaneously, as our approach is devised to classify critical vs. non-critical recordings while detecting the most discriminative frequency bands. The learning pipeline is applied to a data set of 18 patients for a total of 2347 neural recordings analyzed by medical experts. Without any prior knowledge assumption, the data-driven method reveals the most discriminative frequency bands for the localization of epileptic areas in the high-frequency spectrum (>=80 Hz) while showing high performance metric scores (mean balanced accuracy of 0.89 +- 0.03). The promising results may represent a starting point for the automatic search of clinical biomarkers of epileptogenicity

Space transfer vehicle concepts and requirements. Volume 2, book 2: Appendix

This appendix describes the work that was performed to define the Lunar transfer vehicle and Lunar excursion vehicle which were part of the 'Report of the 90-Day Study on Human Exploration of the Moon and Mars.' A detailed concept definition of both vehicles including overall dimensions, mass properties, subsystem definition, and operational flight sequences is included

Comparative and statistical analysis between the CERN conference database and three other bases

This is a comparison between three scientific conference databases and CERN data. High Energy Physics institutes DESY and SLAC databases and the STN-FIZ commercial one's are described and analysed by statistical tables. We plan to work out a co-operation policy especially with DESY for exchange or data import

Atwater Kent Power Panel Console

The focuses of this Major Qualifying Project (MQP) are: the upgrade of media displayed on the Atwater Kent Power Panels, the addition of a Smart Mirror, and the relocation of the Independent Grid Solar Charging Station. Changes were made to the features of two past MQP’s: Atwater Kent Power Panel (2016) and Grid Independent Charging Station with Power FlowDisplay (2012). These projects are accessible to everyday users and highlight the awareness of energy usage within Atwater Kent. A Smart Mirror will be able to reduce the amount of power consumed by the Power Panels by not allowing the system to be on for a long period of time. This new combination of systems provides the Atwater Kent community with an interactive method of conveyed energy usage and previous MQP’s

A novel genotyping approach to improve transfusion support for patients with HLA and/or HPA alloantibodies

Patients who require platelet transfusion support but have become sensitised to Human Leucocyte Antigens (HLA) or Human Platelet Antigens (HPA) require suitably matched or selected products to avoid adverse transfusion reactions resulting from antibodies reacting with the transfused product. Provision of compatible products for these patients is often challenging, and requires significant resources from the blood service. This study set out to develop and implement next generation sequencing (NGS) technology to enhance the HLA and HPA definition of both platelet donors and recipients.An NGS based method was designed and developed for high throughput, allele level HLA class I genotyping and used to evaluate the impact of NGS technology on the selection of platelet donors using HLA epitope matching (HEM). In addition, an alternative NGS approach was designed to simultaneously sequence the six genes that code for glycoproteins expressing HPA in order to define all known HPA systems in both donor and patient samples.Allele level HLA-A, -B and –C genotypes were generated for 519 platelet donors by NGS. A critical evaluation of algorithms used to predict alleles from low to medium resolution HLA types demonstrated that NGS was more accurate when determining HLA epitopes for the selection of platelets by HEM. The HLA genotyping data obtained was used to establish previously undefined HLA allele and haplotype frequencies at third field resolution in the English platelet donor population. This thesis also includes the first reported NGS based method for the simultaneous genotyping of HPA-1 to HPA-29, with the additional capability of novel HPA detection. NGS has been shown to significantly improve the definition of both HLA and HPA genetic systems and will provide a number of future benefits for laboratories and the patients they support, including provision of well matched transfusion products, the detection of rare or novel polymorphisms and increased knowledge of HLA and HPA frequencies

Solving the nearest rotation matrix problem in three and four dimensions with applications in robotics

Aplicat embargament des de la data de defensa fins ei 31/5/2022Since the map from quaternions to rotation matrices is a 2-to-1 covering map, this map cannot be smoothly inverted. As a consequence, it is sometimes erroneously assumed that all inversions should necessarily contain singularities that arise in the form of quotients where the divisor can be arbitrarily small. This misconception was clarified when we found a new division-free conversion method. This result triggered the research work presented in this thesis. At first glance, the matrix to quaternion conversion does not seem to be a relevant problem. Actually, most researchers consider it as a well-solved problem whose revision is not likely to provide any new insight in any area of practical interest. Nevertheless, we show in this thesis how solving the nearest rotation matrix problem in Frobenius norm can be reduced to a matrix to quaternion conversion. Many problems, such as hand-eye calibration, camera pose estimation, location recognition, image stitching etc. require finding the nearest proper orthogonal matrix to a given matrix. Thus, the matrix to quaternion conversion becomes of paramount importance. While a rotation in 3D can be represented using a quaternion, a rotation in 4D can be represented using a double quaternion. As a consequence, the computation of the nearest rotation matrix in 4D, using our approach, essentially follow the same steps as in the 3D case. Although the 4D case might seem of theoretical interest only, we show in this thesis its practical relevance thanks to a little known mapping between 3D displacements and 4D rotations. In this thesis we focus our attention in obtaining closed-form solutions, in particular those that only require the four basic arithmetic operations because they can easily be implemented on microcomputers with limited computational resources. Moreover, closed-form methods are preferable for at least two reasons: they provide the most meaningful answer because they permit analyzing the influence of each variable on the result; and their computational cost, in terms of arithmetic operations, is fixed and assessable beforehand. We have actually derived closed-form methods specifically tailored for solving the hand-eye calibration and the pointcloud registration problems which outperform all previous approaches.Dado que la función que aplica a cada cuaternión su matrix de rotación correspondiente es 2 a 1, la inversa de esta función no es diferenciable en todo su dominio. Por consiguiente, a veces se asume erróneamente que todas las inversiones deben contener necesariamente singularidades que surgen en forma de cocientes donde el divisor puede ser arbitrariamente pequeño. Esta idea errónea se aclaró cuando encontramos un nuevo método de conversión sin división. Este resultado desencadenó el trabajo de investigación presentado en esta tesis. A primera vista, la conversión de matriz a cuaternión no parece un problema relevante. En realidad, la mayoría de los investigadores lo consideran un problema bien resuelto cuya revisión no es probable que proporcione nuevos resultados en ningún área de interés práctico. Sin embargo, mostramos en esta tesis cómo la resolución del problema de la matriz de rotación más cercana según la norma de Frobenius se puede reducir a una conversión de matriz a cuaternión. Muchos problemas, como el de la calibración mano-cámara, el de la estimación de la pose de una cámara, el de la identificación de una ubicación, el del solapamiento de imágenes, etc. requieren encontrar la matriz de rotación más cercana a una matriz dada. Por lo tanto, la conversión de matriz a cuaternión se vuelve de suma importancia. Mientras que una rotación en 3D se puede representar mediante un cuaternión, una rotación en 4D se puede representar mediante un cuaternión doble. Como consecuencia, el cálculo de la matriz de rotación más cercana en 4D, utilizando nuestro enfoque, sigue esencialmente los mismos pasos que en el caso 3D. Aunque el caso 4D pueda parecer de interés teórico únicamente, mostramos en esta tesis su relevancia práctica gracias a una función poco conocida que relaciona desplazamientos en 3D con rotaciones en 4D. En esta tesis nos centramos en la obtención de soluciones de forma cerrada, en particular aquellas que solo requieren las cuatro operaciones aritméticas básicas porque se pueden implementar fácilmente en microcomputadores con recursos computacionales limitados. Además, los métodos de forma cerrada son preferibles por al menos dos razones: proporcionan la respuesta más significativa porque permiten analizar la influencia de cada variable en el resultado; y su costo computacional, en términos de operaciones aritméticas, es fijo y evaluable de antemano. De hecho, hemos derivado nuevos métodos de forma cerrada diseñados específicamente para resolver el problema de la calibración mano-cámara y el del registro de nubes de puntos cuya eficiencia supera la de todos los métodos anteriores.Postprint (published version

Investigación de la distribución de los alelos HLA en poblaciones sanas y enfermas mediante la aplicación de nuevas metodologías de secuenciación

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Medicina, Departamento de Inmunología, Oftalmología y ORL, leída el 09/03/2021Increasing our knowledge of the HLA system, including both the complete sequence description and the assessment of its diversity at the worldwide human population-level, is of great importance for elucidating the molecular functional mechanisms of the immune system and its regulation in health and disease. Furthermore, assessment of HLA allelic and haplotypic diversity of each human population is essential in the clinical histocompatibility and transplantation setting as well as in the pharmacogenetics, immunotherapy and anthropology fields. Nevertheless, the inherent vast polymorphism and high complexity presented by the HLA system have been an important challenge for its unambiguous and in-depth (high-resolution) characterization by previously available legacy molecular HLA genotyping methods (e.g. SSP, SSO and even SBT). Recent application of novel next-generation sequencing (NGS) technology for high-resolution molecular HLA genotyping has enabled to obtain, at a high-throughput mode and larger scale, full-length and/or extended sequences and genotypes of all major HLA genes, thus overcoming most of these previous limitations. Objectives: I) Characterization of HLA allele and haplotype diversity of all major classical HLA genes (HLA-A, -B, -C, -DPA1, -DPB1, -DQA1, -DQB1, -DRB1 and -DRB3/4/5) by application of NGS of a first representative cohort of the Spanish population that could also serve as a healthy control reference group. Respective statistical analyses were performed for this immunogenetic population data. II) Characterization of HLA allele and haplotype diversity of all major classical HLA genes (HLA-A, -B, -C, -DPA1, -DPB1, -DQA1, -DQB1, -DRB1 and -DRB3/4/5) by application of NGS of a respective cohort of multiple sclerosis (MS) patients in the Spanish population (recruited at the Department of Neurology, Hospital Clínic, Barcelona, Catalonia, Spain). A first case-control study was carried out to examine HLA-disease associations with MS in these Spanish population cohorts as well as to attempt a fine-mapping of these allele and haplotype associations by full gene resolution level via NGS. In addition, a second analysis exercise (i.e. test case) of this case-control study was carried out using an alternative healthy control group dataset, exclusively from the Spanish northeastern region of Catalonia in this second case, to evaluate possible differences in the findings of HLA-disease association with MS due to plausible regional HLA genetic variation within mainland Spain (i.e. as a statistical way to try controlling for any possible existing population stratification)...El estudio del sistema HLA, incluyendo la descripción completa de su secuencia y de la diversidad de este complejo HLA a nivel poblacional, es de gran importancia de cara a poder entender los mecanismos moleculares y funciones del sistema inmune así como su regulación en individuos sanos y enfermos. Además, la caracterización exhaustiva de la diversidad de alelos y haplotipos HLA de cada población humana es esencial en el campo de la inmunología de trasplante e histocompatibilidad al igual que en las áreas de farmacogenética e inmunoterapia. El inmenso polimorfismo y gran complejidad que presenta el sistema HLA han sido hasta ahora importantes barreras de cara a poder caracterizarlo en gran detalle (por alta resolución) y sin ambigüedades mediante métodos de genotipaje HLA tradicionales disponibles (como son SSP, SSO o incluso SBT). La reciente aplicación de la novedosa tecnología de secuenciación masiva NGS para el genotipaje molecular HLA por alta resolución ha posibilitado obtener secuencias completas o mucho más extendidas para genotipos de los principales genes de HLA, superándose así estas previas limitaciones. Objetivos: I) Caracterización de la diversidad alélica y haplotípica de los principales genes HLA (HLA-A, -B, -C, -DPA1, -DPB1, -DQA1, -DQB1, -DRB1 y -DRB3/4/5) mediante la aplicación de NGS en una primera cohorte representativa de la población española que, igualmente, constituirá una población control de referencia para estudios de asociación de HLA y enfermedades. También, respectivos análisis estadísticos se realizaron para estos resultados de genotipaje HLA. II) Caracterización de la diversidad alélica y haplotípica de los principales genes HLA (HLA-A, -B, -C, -DPA1, -DPB1, -DQA1, -DQB1, -DRB1 y -DRB3/4/5) mediante la aplicación de NGS en una correspondiente cohorte de pacientes con esclerosis múltiple (EM) de la población española (reclutados y procedentes del Departamento de Neurología del Hospital Clínic (Barcelona, Cataluña)). Un primer estudio de asociación HLA tomando casos (pacientes EM) frente a controles sanos se llevó a cabo para examinar la asociación de genes HLA y la enfermedad de EM en estas cohortes de población española antes mencionadas. Así se buscaba realizar un mapeo fino de las respectivas asociaciones alélicas y haplotípicas de HLA mediante la gran resolución alélica proporcionada por esta metodología de secuenciación masiva. De modo adicional, y como un segundo ejercicio de análisis en este estudio de asociación HLA, se utilizó un grupo control sano alternativo al previo, que incluía individuos procedentes de la región de Cataluña (situada al noreste de España) exclusivamente en este caso, para evaluar así posibles diferencias dadas en la asociación de HLA con EM debido a la probable variación genética en HLA existente a nivel regional dentro del territorio de España...Fac. de MedicinaTRUEunpu

A country with non-existent unemployment: The special characteristics of the Czech labour market. OSW Report July 2019

The low unemployment rate in the Czech Republic is an effect of a number of structural and political factors which have generated a certain economic potential. This potential was achieved when external stimuli occurred in the form of economic boom, which has been visible especially since 2014. The policy adopted by each of the Czech governments during the recent recession and stagnation was of great significance, alongside the support for the economic policy through actions taken by the National Bank of the Czech Republic (above all the low interest rate policy and interventions on the currency market). One of the reasons why the unemployment rate in the Czech Republic continues to be low is the relatively low labour costs and the high level of the country’s industrialisation where the automotive industry, which heavily relies on the market situation, has an essential share. So-called ‘assembly plants’, i.e. industrial plants generating numerous jobs with low added value, also play an important role in reducing the scale of unemployment. A great number of such plants have been created in effect of investment incentives over the past twenty years (the wave reached its peak in 1998–2007). They were often created with the intention of reducing unemployment. At the same time, the Czech Republic, a developed country heavily reliant on exports, is extremely sensitive to changes in the economic situation in Europe. The Czech economy is particularly strongly influenced by the situation in other EU member states, which are the outlet for almost 85% of the Czech exports. Germany is a major player in this context as it accounts for a third of Czech exports and a quarter of its imports, and has engaged its capital fairly intensively in the Czech Republic