Numerical Analysis of Passively Mode-Locked Quantum-Dot Lasers With Absorber Section at the Low-Reflectivity Output Facet

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Personalized screening and risk profiles for Mild Cognitive Impairment via a Machine Learning Framework: Implications for general practice.

peer reviewedOBJECTIVES: Diagnosis of Mild Cognitive Impairment (MCI) requires lengthy diagnostic procedures, typically available at tertiary Health Care Centers (HCC). This prospective study evaluated a flexible Machine Learning (ML) framework toward identifying persons with MCI or dementia based on information that can be readily available in a primary HC setting. METHODS: Demographic and clinical data, informant ratings of recent behavioral changes, self-reported anxiety and depression symptoms, subjective cognitive complaints, and Mini Mental State Examination (MMSE) scores were pooled from two aging cohorts from the island of Crete, Greece (N = 763 aged 60-93 years) comprising persons diagnosed with MCI (n = 277) or dementia (n = 153), and cognitively non-impaired persons (CNI, n = 333). A Balanced Random Forest Classifier was used for classification and variable importance-based feature selection in nested cross-validation schemes (CNI vs MCI, CNI vs Dementia, MCI vs Dementia). Global-level model-agnostic analyses identified predictors displaying nonlinear behavior. Local level agnostic analyses pinpointed key predictor variables for a given classification result after statistically controlling for all other predictors in the model. RESULTS: Classification of MCI vs CNI was achieved with improved sensitivity (74 %) and comparable specificity (73 %) compared to MMSE alone (37.2 % and 94.3 %, respectively). Additional high-ranking features included age, education, behavioral changes, multicomorbidity and polypharmacy. Higher classification accuracy was achieved for MCI vs Dementia (sensitivity/specificity = 87 %) and CNI vs Dementia (sensitivity/specificity = 94 %) using the same set of variables. Model agnostic analyses revealed notable individual variability in the contribution of specific variables toward a given classification result. CONCLUSIONS: Improved capacity to identify elderly with MCI can be achieved by combining demographic and medical information readily available at the PHC setting with MMSE scores, and informant ratings of behavioral changes. Explainability at the patient level may help clinicians identify specific predictor variables and patient scores to a given prediction outcome toward personalized risk assessment

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

Finding the place of the artisan in developing Woodstock

Argument - The relationship between Cape Town and its socio-economic change has resulted in developments often disassociated with immediate context ,but rather following capitalist ideals with very little to no variation. This results in social alienation of existing communities with the new developments. These new developments are internalized enclave models with no engagement to their edge conditions but in the case of Woodstock, are selected solely for their proximity to the city center and their low start-up cost. These developments are also restricted to the measures of the urban scale and take a place in the morphology of the city by creating a new dialogue and place. However they do add value to the city and initiate a flurry of similar developments around them using the basic model of the enclave. In this dissertation I propose the existence of a hybrid model that lies between syntactic values learnt from enclaves of malls and the armatures of the main street/s. By engaging with examples like the biscuit mill and Woodstock exchange and looking into their syntactic structure in comparison to the structure of dedicated malls (such as canal walk), I will be able to construct a set of design characteristics from which I can propose a new spatial model. This together with a critical look at the two main roads (Victoria road and Albert road) that run through Woodstock there will be enough local research into the overall form of the two contrasting models. Question - Dealing with an existing urban fabric which has undergone many infrastructural changes over the past 40 years, the new model of the enclave takes on a new form in Woodstock yet is bound by the spatial parameters of the existing morphology. The question of how much how much can we change something without losing its original value whilst working within its limitations? Locating the design intervention - Based on the theoretical research into enclaves and armatures, I isolate "anchors" which facilitate the function of an enclave and act as the main attractors of people. Naturally spaces form around these "anchors" and a series of linear paths leading up to them. In the case of Woodstock I have chosen the Woodstock station, and its adjacent site. The main intervention is this site and its structures climaxing at the stations entrance. The initial diagrams are a series of models and sketches which explore the path/ sand structures supporting this movement. The programme itself builds off the tradition of artisans and craftsmen of the area which manufacture, market and sell in the same space. Tectonics are derived from the typology of the buildings found on site and are tailored related to the artisans who will use these spaces. The existing structure contributes to the overall expression and is explored as an adaptable spatial model. Conclusion - Describing a new model is context dependant and the theory serves as a guiding set of rules which are used to establish the argument. Breaking of these rules creates the new but must be critically analysed for is values or its shortcomings

Evaluation of an Erbium-Doped Fiber Ring Laser as an Edge Filtering Device for Fiber Bragg Grating Sensor Interrogation

An easy-to-implement and cost-effective Fiber Bragg Grating (FBG) sensor interrogation technique based on a ring Erbium-Doped Fiber Laser (EDFL) topology is proposed and experimentally assessed. The FBG sensor is part of the EDFL cavity and must have a central wavelength located within the linear region of the EDF’s amplified spontaneous emission (ASE) spectrum, which occurs at between 1530 and 1540 nm. In this manner, the wavelength-encoded response of the FBG under strain is converted to a linear variation in the laser output power, removing the need for spectrum analysis as well as any limitations from the use of external edge-filtering components. In addition, the laser linewidth is significantly reduced with respect to the FBG bandwidth, thus improving the resolution of the system, whereas its sensitivity can be controlled through pumping power. The performance of the system has been characterized by modeling and experiments for EDFs with different lengths, doping concentrations, and pumping power levels. The influence of mode-hopping in the laser cavity on the resolution and accuracy of the system has also been investigated

Compact optical displacement sensing by detection of microwave signals generated from a monolithic passively mode-locked laser under feedback

A monolithic passively mode-locked laser is proposed as a compact optical sensor for displacements and vibrations of a reflecting object. The sensing principle relies on the change of the laser repetition frequency that is induced by optical feedback from the object under measurement. It has been previously observed that, when a semiconductor passively mode locked laser receives a sufficient level of optical feedback from an external reflecting surface it exhibits a repetition frequency that is no more determined by the mode-locking rule of the free-running operation but is imposed by the length of the external cavity. Therefore measurement of the resulting laser repetition frequency under self-injection permits the accurate and straightforward determination of the relative position of the reflecting object. The system has an inherent wireless capability since the repetition rate of the laser can be wirelessly detected by means of a simple antenna which captures the microwave signal generated by the saturable absorber and is emitted through the wiring of the laser. The sensor setup is very simple as it requires few optical components besides the laser itself. Furthermore, the deduction of the relative position of the reflecting object is straightforward and does not require any processing of the detected signal. The proposed sensor has a theoretical sub-wavelength resolution and its performance depends on the RF linewidth of the laser and the resolution of the repetition frequency measurement. Other physical parameters that induce phase changes of the external cavity could also be quantified

Traitement ultrarapide de signaux optiques par effets non-linéaires quadratiques (échantillonnage optique et commutation spatiale par effet soliton)

Les travaux présentés dans cette thèse portent sur l'étude expérimentale des effets quadratiques et la mise à profit pour la réalisation des fonctions tout-optiques ultra-rapides, telles que l'échantillonnage optique à très haute résolution temporelle, la commutation spatiale, le routage et le démultiplexage en longeur d'onde. La première partie de travaux porte sur la réalisation d'un échantillonneur tout-optique basé sur un processus de somme des fréquences type II. L'objectif visé est l'application à la réflectométrie optique à haute résolution spatiale pour des réseaux multimodes courte distance. Les résultats obtenus laissent espérer une résolution spatiale de 1,2 cm dans une future réelle mesure de réflectométrie. La deuxième partie est consacrée sur l'étude de la propagation autoguidée par doublage de fréquence de type II dans un cristal de KTP. Nous rapportons la toute première mesure du contenu énergétique des solitons spatiaux quadratiques, les premières expériences sur leur génération part des ondes incidentes non-colinéaires et la première observation expérimentale de régimes de fusion, de répulsion ou d'enroulement en spirale de deux solitons quadratiques bicolores en fonction de leur phase relative et de l'écart initial entre les trajectoires des faisceaux. Ces études nous ont permis de proposer et caractériser un moyen pour une remise en forme spatiale des faisceaux, un filtre en intensité pour la remise en forme temporelle d'impulsions déformées, un comparateur optique et un système d'adressage tout-optique de un vers douze canaux. Tous ces dispositifs sont capables de fonctionner à très hauts débits (100Gbits/sec). La réalisation et caractérisation d'un laser impulsionnel à modes bloqués émettant simultanément sur plusieurs longueurs d'onde fait l'objet du dernier chapitre de cette thèse. Ceci est la première étape vers la démonstration de la faisabilité d'un dispositif capable d'effectuer un adressage sensible à la longueur d'onde.LIMOGES-BU Sciences (870852109) / SudocSudocFranceF

Computationally Efficient Context-Free Named Entity Disambiguation with Wikipedia

The induction of the semantics of unstructured text corpora is a crucial task for modern natural language processing and artificial intelligence applications. The Named Entity Disambiguation task comprises the extraction of Named Entities and their linking to an appropriate representation from a concept ontology based on the available information. This work introduces novel methodologies, leveraging domain knowledge extraction from Wikipedia in a simple yet highly effective approach. In addition, we introduce a fuzzy logic model with a strong focus on computational efficiency. We also present a new measure, decisive in both methods for the entity linking selection and the quantification of the confidence of the produced entity links, namely the relative commonness measure. The experimental results of our approach on established datasets revealed state-of-the-art accuracy and run-time performance in the domain of fast, context-free Wikification, by relying on an offline pre-processing stage on the corpus of Wikipedia. The methods introduced can be leveraged as stand-alone NED methodologies, propitious for applications on mobile devices, or in the context of vastly reducing the complexity of deep neural network approaches as a first context-free layer

AUSTRALASIAN JOURNAL OF COMBINATORICS Volume 47 (2010), Pages 11–20 New classes of orthogonal designs and weighing matrices derived from near normal sequences

Directed sequences have been recently introduced and used for constructing new orthogonal designs. The construction is achieved by multiplying the length and type of suitable compatible sequences. In this paper we show that near normal sequences of length n =4m +1 canbe used to construct four directed sequences of lengths 2m +1, 2m +1, 2m, 2m and type (4m +1, 4m +1) = (n, n) with zero NPAF. The above method leads to the construction of many large orthogonal designs. In addition, we obtain new infinite families of weighing matrices constructed by near normal sequences, such as W (156 + 4k,125), W (160 + 4k,144), W (200 + 4k,196) and W (276 + 4k,225) for all k ≥ 0. These families resolve the existence and construction of over 30 weighing matrices which are listed as open in the second edition of the Handbook of Combinatorial Designs. 1 Introduction and preliminary results An orthogonal design of order n and type (s1,s2,...,su) (si> 0), denoted OD(n