Modal Testing And Analysis Techniques And Their Application On A Small Uas

This thesis focuses on experimental structural analysis using contemporary testing techniques. This includes modal testing topics such as data acquisition, data processing, sensor placement, and multiple excitation methods. It also presents a novel sensor placing procedure that uses a laser vibrometer to identify key sensor locations. These techniques are applied in a case study on a small unmanned aerial system, (UAS). The airframe, the BTE Super Hauler, is a small UAS used by the Unmanned Aircraft Systems Engineering (UASE) Laboratory at the University of North Dakota as a test platform for flight testing multiple payloads. An antenna system, designed for use in sense and avoid applications, was developed that requires the addition of wing pods to the current airframe to minimize electro-magnetic interference from the engine of the UAS. Modal testing is used to determine the effect of two wing pods on the structural dynamic behavior of the UAS. Flutter analysis is also performed to ensure that the surface bending and torsional modes of the UAS do not create an unstable airframe. Data acquisition was performed using ModalVIEW, a structural analysis program supported by LabVIEW. ModalVIEW outputs a frequency response function to which various windowing methods can be applied. The aircraft was excited both by an impact hammer and a shaker. The new sensor placement procedure was developed to assist in placing sensors in key locations in an efficient method to reduce the number of channels needed. It is also a fast, non-contact method implementing a laser vibrometer. A statistical method was used to determine appropriate sensor locations

Adaptive kernel estimation of the baseline function in the Cox model, with high-dimensional covariates

The aim of this article is to propose a novel kernel estimator of the baseline function in a general high-dimensional Cox model, for which we derive non-asymptotic rates of convergence. To construct our estimator, we first estimate the regression parameter in the Cox model via a Lasso procedure. We then plug this estimator into the classical kernel estimator of the baseline function, obtained by smoothing the so-called Breslow estimator of the cumulative baseline function. We propose and study an adaptive procedure for selecting the bandwidth, in the spirit of Gold-enshluger and Lepski (2011). We state non-asymptotic oracle inequalities for the final estimator, which reveal the reduction of the rates of convergence when the dimension of the covariates grows

Oracle inequalities for the Lasso in the high-dimensional Aalen multiplicative intensity model

In a general counting process setting, we consider the problem of obtaining a prognostic on the survival time adjusted on covariates in high-dimension. Towards this end, we construct an estimator of the whole conditional intensity. We estimate it by the best Cox proportional hazards model given two dictionaries of functions. The first dictionary is used to construct an approximation of the logarithm of the baseline hazard function and the second to approximate the relative risk. We introduce a new data-driven weighted Lasso procedure to estimate the unknown parameters of the best Cox model approximating the intensity. We provide non-asymptotic oracle inequalities for our procedure in terms of an appropriate empirical Kullback divergence. Our results rely on an empirical Bernstein's inequality for martingales with jumps and properties of modified self-concordant functions

Rethinking Organizational Leader Identity Development: A Social Network and Ethnographic Approach

I propose a nuanced theoretical approach to understanding leader identity development in organizations. Past identity work has ignored or tangentially addressed phases of development that I term `leader identity stagnation' and `leader identity destruction'. Analysis of survey and network data examining West Point cadets' identities and friendship, leadership, and trust networks adds insight into the leader identity development process. Ethnographic research of the institution offers further understanding and helps confirm the new theoretical model of the phases of leader identity development. A concluding chapter examines the application of new social networking technologies and mixed-media interaction to enhance organizational leader identity construction. A gap exists in management literature pertaining to the creation and use of social network technologies for this purpose

Estimation and variable selection in a joint model of survival times and longitudinal outcomes with random effects

This paper considers a joint survival and mixed-effects model to explain the survival time from longitudinal data and high-dimensional covariates. The longitudinal data is modeled using a nonlinear effects model, where the regression function serves as a link function incorporated into a Cox model as a covariate. In that way, the longitudinal data is related to the survival time at a given time. Additionally, the Cox model takes into account the inclusion of high-dimensional covariates. The main objectives of this research are two-fold: first, to identify the relevant covariates that contribute to explaining survival time, and second, to estimate all unknown parameters of the joint model. For that purpose, we consider the maximization of a Lasso penalized likelihood. To tackle the optimization problem, we implement a pre-conditioned stochastic gradient to handle the latent variables of the nonlinear mixed-effects model associated with a proximal operator to manage the non-differentiability of the penalty. We provide relevant simulations that showcase the performance of the proposed variable selection and parameters' estimation method in the joint modeling of a Cox and logistic model

Création, révélation et rédemption dans le rationalisme juif médiéval

Ce qui s’apparente chez les rationalistes juifs du Moyen Âge à une « neutralisation » du messianisme avant l’heure constitue en réalité une authentique pensée du messianisme. Il ne s’agit pas seulement de conforter l’autorité de la loi, mais d’en proposer une certaine compréhension, dans son rapport fondamental à l’exil d’une part et à la vérité de l’autre. Ce dispositif se construit dans l’articulation ou la désarticulation des notions de création, de révélation et de rédemption. De Maïmonide à Yosef Albo, deux voies ont été proposées. La voie maïmonidienne consiste à faire des temps messianiques une garantie de l’éternité et de la perfection de la Torah. La voie de certains post-maïmonidiens consiste au contraire à réduire la rédemption à une croyance révélée dans la Torah, mais en aucun cas indispensable à celle-ci. Le même mouvement s’opère s’agissant de la création.The anti-apocalyptic approach to messianism advocated by Medieval Jewish rationalists shall not be reduced to their will to preserve the authority of the law. It aims rather at offering a certain understanding of the law, envisaged through both its relationship with exile and with truth. This dispositive lies on the articulation or disarticulation of the notions of creation, revelation and redemption. From Maimonides to Yosef Albo, two paths were proposed. Maimonides turned the messianic era into a guaranty of the eternity and of the perfection of the Torah. Some post-Maimonidean thinkers contrarily reduced redemption to the status of a belief that was revealed in the Torah, but that is in no way one of its necessary conditions. An analogous movement might be observed as regards the belief in creation

Spinoza, critique ou lecteur radical de Maïmonide ?

Le traitement de la figure de Moïse reflète la relation ambivalente de Spinoza à Maïmonide. Derrière la polémique manifeste contre le maître médiéval, se cache une lecture ésotérique du Guide des égarés. Que Moïse n’ait été qu’un législateur talentueux à l’imagination particulièrement fertile (et nullement un philosophe) est une thèse que certains de ses lecteurs averroïstes attribuaient déjà à Maïmonide. Spinoza s’inscrit dans leur filiation en transférant vers Jésus les caractéristiques que Maïmonide prête à Moïse tout en reprenant, à son sujet, les mêmes procédés d’écriture complexes que ceux à l’œuvre dans le Guide à propos de Moïse.The treatment he reserves for Moses reflects Spinoza’s ambivalent relationship to Maimonides. The manifest polemic against the Medieval master on this point hides an esoteric reading of the Guide of the Perplexed. That Moses was only a talented lawgiver with a particularly vivid imagination (and in no way a philosopher) is a thesis already ascribed to Maimonides by some of his Averroist readers. Spinoza follows in their footsteps in transferring to Jesus the characteristics Maimonides attributes to Moses and applying to him the same complex writing strategies used in the Guide in relation to Moses

Entre éternité et contingence : la Loi chez Maïmonide

In his Mishneh Torah, Maimonides insists on the immutability of the Torah and describes the messianic era as a time when it will be completely restored. On the contrary, some passages from his Guide of the perplexed seem to draw a conception of the Mitswot (commandments) according to which they are determined, as far as their content is concerned, by the general human behaviours at the time of the revelation of the Torah. In other words, once these specific behaviours disappeared, the commandments became obsolete. In this study, I try to reconcile these two theses, by suggesting that this very contradiction hints at a unitary and original conception of Law, temporarily inapplicable in its entirety, yet absolutely effective and significant at all time, appropriate thus for its principal aim: combating a perverted rapport with the world and with the laws, which is referred to as idolatry

L’aporie de Lorki : une croyance peut-elle être réfléchie ?

Les textes du passé, même marginaux, d’apparence anecdotique, ne sont pas le domaine réservé des «  historiens antiquaires  » de la Deuxième Considération intempestive de Nietzsche. Ils peuvent au contraire constituer pour nous un réservoir de réflexions et une incitation à penser. On trouve ainsi, dans un petit texte de circonstance aux allures de curiosité historique, une réflexion saisissante sur la notion de croyance, à même – à condition toutefois de se mettre à son écoute – de nous mene..

El judaísmo, una tradición rebelde

“La rebelión de los hijos, ese tema tan común en la literatura de principios del siglo [xx], ha alcanzado en el microcosmos familiar judío la dimensión de una verdadera inversión de valores”. El sintagma “rebelión de los hijos”, que emplea Stéphane Mosès acerca de la revuelta de determinados jóvenes intelectuales judíos contra sus padres asimilacionistas en la Alemania de principios del siglo XX, resuena como un eco de la figura bíblica del “hijo obstinado y rebelde”. Pero el hijo rebelde del..