The Age of Advancing PocketQube Technology

The PocketQube Standard (5cm cube) is a quickly advancing technology branch which can trace it origins back to the CubeSat standard. The community has grown from a handful of builders to in excess of 25 with most of the developments coming from Europe. Alba has pioneered standardized deployers called AlbaPods, capable of launching 6p and 96p worth of up mass. 9 PocketQubes are scheduled to launch in 2019 on two separate Alba Launch Clusters, offering the community an outlet to get to orbit regularly for the first time. In addition, Alba has developed the most advanced PocketQube in its class, Unicorn-2. Unicorn-2 can generate 20 watt peak, 10-15w OAP, 200kb/s downlink and 5 degrees pointing on a full ADCS

Compact and Planar End-fire Antenna for PicoSat and CubeSat Platforms to Support Deployable Systems

A miniaturized planar Yagi-Uda antenna for integration with PicoSats or other SmallSat missions is proposed. Miniaturization techniques, such as meandering and 1-D artificial dielectric concepts to reduce the guided wavelength, are employed to overcome space constraints imposed by the SmallSat footprint while still maintaining good performance for the FR-4 antenna. Simulations and measurements have been carried out on the Unicorn-2 PicoSat chassis from Alba Orbital and are in good agreement. Also, antenna dimensions have been reduced between 15% and 66% when compared to a more conventional planar Yagi-Uda antenna working at the same frequency. This compactness allows for simple integration with the deployable solar panel array of the Unicorn-2 PicoSat spacecraft. Full end-fire radiation is achieved and peak gain values are about 5 dBi for the antenna when fully integrated on the satellite chassis, offering an attractive solution for downlink connectivity. This compact antenna design can also be used within an array for beam steering or integrated within the solar cell modules of other PicoSats, CubeSats and SmallSats. Applications include Earth observation, remote sensing, as well as SmallSat to ground station communications. The planar Yagi-Uda antenna may also be useful wherever end-fire radiation is required from a compact antenna structure

Improved estimation of the left ventricular ejection fraction using a combination of independent automated segmentation results in cardiovascular magnetic resonance imaging

—This work aimed at combining different segmenta-tion approaches to produce a robust and accurate segmentation result. Three to five segmentation results of the left ventricle were combined using the STAPLE algorithm and the reliability of the resulting segmentation was evaluated in comparison with the result of each individual segmentation method. This comparison was performed using a supervised approach based on a reference method. Then, we used an unsupervised statistical evaluation, the extended Regression Without Truth (eRWT) that ranks different methods according to their accuracy in estimating a specific biomarker in a population. The segmentation accuracy was evaluated by focusing on the left ventricular ejection fraction (LVEF) estimate resulting from the LV contour delineation using a public cardiac cine MRI database. Eight different segmentation methods, including three expert delineations, were studied, and sixteen combinations of the five automated methods were investigated. The supervised and unsupervised evaluations demonstrated that in most cases, STAPLE results provided better estimates of the LVEF than individual automated segmentation methods. In addition, LVEF obtained with STAPLE were within inter-expert variability. Overall, combining different automated segmentation methods improved the reliability of the segmenta-tion result compared to that obtained using an individual metho

Swift trust and commitment: the missing links for humanitarian supply chain coordination?

Coordination among actors in a humanitarian relief supply chain decides whether a relief operation can be or successful or not. In humanitarian supply chains, due to the urgency and importance of the situation combined with scarce resources, actors have to coordinate and trust each other in order to achieve joint goals. This paper investigated empirically the role of swift trust as mediating variable for achieving supply chain coordination. Based on commitment-trust theory we explore enablers of swift-trust and how swift trust translates into coordination through commitment. Based on a path analytic model we test data from the National Disaster Management Authority of India. Our study is the first testing commitment-trust theory (CTT) in the humanitarian context, highlighting the importance of swift trust and commitment for much thought after coordination. Furthermore, the study shows that information sharing and behavioral uncertainty reduction act as enablers for swift trust. The study findings offer practical guidance and suggest that swift trust is a missing link for the success of humanitarian supply chains

Segmentation automatisée du ventricule gauche en IRM cardiaque : Evaluation supervisée et non supervisée de cette approche et application à l'étude de la viabilité myocardique

The aim of this work is to perform an automated segmentation of the Left Ventricle on short-axis cardiac MR images with as few user interactions as possible. Based on a recently developed semi-automated segmentation method, a fully automated segmentation method is proposed that includes three main steps: the heart localization, the definition of a region of interest around the left ventricle, and finally its segmentation. The algorithm developed here takes into account anatomic and functional a priori information such as the temporal features of the heartbeat, the pseudo-circular shape of the LV, and the 3D continuity, combined with the image intensity features. The segmentation process is achieved using deformable models combined with morphological filters, which improve the model performances when dealing with heterogeneous gray levels within the cavity. The work achieved within the MedIEval group (Medical Imaging Evaluation) allowed to compare both proposed methods with 6 other methods, including 3 manual delineations by experts. In particular, an approach for ranking segmentation methods without using a gold standard was applied to the ejection fractions estimated by the 8 methods. Finally, the proposed segmentation method was used in a clinical research work about the regional contraction and thequantification of the myocardial infarction extent.Future work includes the automated segmentation of the right ventricle as well as the estimation of a robust mutual shape from several segmentation methods.Cette thèse a pour objectif de parvenir à une estimation automatisée des contours du ventricule gauche sur des images IRM en coupes petit-axe, nécessitant un minimum d’interventions de la part de l’utilisateur. En s’appuyant sur une approche semi-automatique récemment développée, une méthode entièrement automatique est proposée, reposant sur la localisation des structures cardiaques et la création d’une région d’intérêt autour du ventricule gauche, puis la segmentation de sa cavité. L’algorithme a été développé en prenant en compte des connaissances anatomiques et fonctionnelles sur le cœur : les caractéristiques temporelles du battement cardiaque, la pseudo-circularité des coupes petit-axe du ventricule gauche, la continuité 3D qui ont été combinées à l’intensité dans les images. La segmentation utilise une approche fondée sur les contours actifs combinée à un filtrage morphologique qui améliore la robustesse de la segmentation vis-à-vis des hétérogénéités au sein de la cavité. Le travail réalisé avec le groupe MedIEval (MedicalImaging Evaluation) a permis de comparer les deux méthodes avec 6 autres méthodes, dont 3 tracés d'experts. Une classification par une approche d’évaluation sans référence a été appliquée à la fraction d’éjection estimée par les 8 méthodes. Enfin, la méthode de segmentation proposée a été utilisée systématiquement dans une étude de recherche clinique combinant l’étude de la contraction régionale et la quantification de la transmuralité de l’infarctus du myocarde. Ces travaux ouvrent des perspectives, sur l’automatisation de la segmentation du ventricule droit et l’estimation d’une forme mutuelle robuste à partir de plusieurs segmentations

Automated segmentation of the left ventricle in cardiac MRI : supervised and non-supervised evaluation of this approach and application to the study of the myocardial viability

Cette thèse a pour objectif de parvenir à une estimation automatisée des contours du ventricule gauche sur des images IRM en coupes petit-axe, nécessitant un minimum d’interventions de la part de l’utilisateur. En s’appuyant sur une approche semi-automatique récemment développée, une méthode entièrement automatique est proposée, reposant sur la localisation des structures cardiaques et la création d’une région d’intérêt autour du ventricule gauche, puis la segmentation de sa cavité. L’algorithme a été développé en prenant en compte des connaissances anatomiques et fonctionnelles sur le cœur : les caractéristiques temporelles du battement cardiaque, la pseudo-circularité des coupes petit-axe du ventricule gauche, la continuité 3D qui ont été combinées à l’intensité dans les images. La segmentation utilise une approche fondée sur les contours actifs combinée à un filtrage morphologique qui améliore la robustesse de la segmentation vis-à-vis des hétérogénéités au sein de la cavité. Le travail réalisé avec le groupe MedIEval (MedicalImaging Evaluation) a permis de comparer les deux méthodes avec 6 autres méthodes, dont 3 tracés d'experts. Une classification par une approche d’évaluation sans référence a été appliquée à la fraction d’éjection estimée par les 8 méthodes. Enfin, la méthode de segmentation proposée a été utilisée systématiquement dans une étude de recherche clinique combinant l’étude de la contraction régionale et la quantification de la transmuralité de l’infarctus du myocarde. Ces travaux ouvrent des perspectives, sur l’automatisation de la segmentation du ventricule droit et l’estimation d’une forme mutuelle robuste à partir de plusieurs segmentations.The aim of this work is to perform an automated segmentation of the Left Ventricle on short-axis cardiac MR images with as few user interactions as possible. Based on a recently developed semi-automated segmentation method, a fully automated segmentation method is proposed that includes three main steps: the heart localization, the definition of a region of interest around the left ventricle, and finally its segmentation. The algorithm developed here takes into account anatomic and functional a priori information such as the temporal features of the heartbeat, the pseudo-circular shape of the LV, and the 3D continuity, combined with the image intensity features. The segmentation process is achieved using deformable models combined with morphological filters, which improve the model performances when dealing with heterogeneous gray levels within the cavity. The work achieved within the MedIEval group (Medical Imaging Evaluation) allowed to compare both proposed methods with 6 other methods, including 3 manual delineations by experts. In particular, an approach for ranking segmentation methods without using a gold standard was applied to the ejection fractions estimated by the 8 methods. Finally, the proposed segmentation method was used in a clinical research work about the regional contraction and thequantification of the myocardial infarction extent.Future work includes the automated segmentation of the right ventricle as well as the estimation of a robust mutual shape from several segmentation methods

Design considerations for frequency scanning transmit antennas in wireless power transmission applications

Scanning transmit antennas can be used in wireless power transmission systems in order to optimize the power budget and energy consumption in the far-field. Here we present a concept for beam scanning that minimizes the need for reconfigurable RF components, such as diodes or varactors, and therefore reduces cost and power handling considerations. Instead the beam steering relies on a frequency scanning principle. In this paper we present the basic theory for designing such a frequency scanning antenna and by means of an example, that conforms with 2.45 GHz ISM band requirements, we evaluate its performance. Analytical and numerical simulations are presented