Multi-kw dc power distribution system study program

The first phase of the Multi-kw dc Power Distribution Technology Program is reported and involves the test and evaluation of a technology breadboard in a specifically designed test facility according to design concepts developed in a previous study on space vehicle electrical power processing, distribution, and control. The static and dynamic performance, fault isolation, reliability, electromagnetic interference characterisitics, and operability factors of high distribution systems were studied in order to gain a technology base for the use of high voltage dc systems in future aerospace vehicles. Detailed technical descriptions are presented and include data for the following: (1) dynamic interactions due to operation of solid state and electromechanical switchgear; (2) multiplexed and computer controlled supervision and checkout methods; (3) pulse width modulator design; and (4) cable design factors

Research study on multi-KW-DC distribution system

A detailed definition of the HVDC test facility and the equipment required to implement the test program are provided. The basic elements of the test facility are illustrated, and consist of: the power source, conventional and digital supervision and control equipment, power distribution harness and simulated loads. The regulated dc power supplies provide steady-state power up to 36 KW at 120 VDC. Power for simulated line faults will be obtained from two banks of 90 ampere-hour lead-acid batteries. The relative merits of conventional and multiplexed power control will be demonstrated by the Supervision and Monitor Unit (SMU) and the Automatically Controlled Electrical Systems (ACES) hardware. The distribution harness is supported by a metal duct which is bonded to all component structures and functions as the system ground plane. The load banks contain passive resistance and reactance loads, solid state power controllers and active pulse width modulated loads. The HVDC test facility is designed to simulate a power distribution system for large aerospace vehicles

The effect of different module configurations on the radiation tolerance of multijunction solar cells

The effect of different module configurations on the performance of multijunction (MJ) solar cells in a radiation environment was investigated. Module configuration refers to the electrical circuit in which the subcells of the multijunction cell are wired. Experimental data for AlCaAs, GaAs, InGaAs, and silicon single-junction concentrator cells subjected to 1 MeV electron irradiation was used to calculate the expected performance of AlGaAs/InGaAs, AlGa/silicon, GaAs/InGaAs, and GaAs/silicon Mj concentrator cells. These calculations included independent, series, and voltage-matched configurations. The module configuration was found to have a significant impact on the radiation tolerance characteristic of the MJ cells

Enrichment of raw sensor data to enable high-level queries

Sensor networks are increasingly used across various application domains. Their usage has the advantage of automated, often continuous, monitoring of activities and events. Ubiquitous sensor networks detect location of people and objects and their movement. In our research, we employ a ubiquitous sensor network to track the movement of players in a tennis match. By doing so, our goal is to create a detailed analysis of how the match progressed, recording points scored, games and sets, and in doing so, greatly reduce the eort of coaches and players who are required to study matches afterwards. The sensor network is highly efficient as it eliminates the need for manual recording of the match. However, it generates raw data that is unusable by domain experts as it contains no frame of reference or context and cannot be analyzed or queried. In this work, we present the UbiQuSE system of data transformers which bridges the gap between raw sensor data and the high-level requirements of domain specialists such as the tennis coach

Five regions, five retinopathy screening programmes: a systematic review of how Portugal addresses the challenge

Background: The implementation of a population-based screening programme for diabetic retinopathy involves several challenges, often leading to postponements and setbacks at high human and material costs. Thus, it is of the utmost importance to promote the sharing of experiences, successes, and difficulties. However, factors such as the existence of regional programmes, specificities of each country’s health systems, organisational and even linguistic barriers, make it difficult to create a solid framework that can be used as a basis for future projects. Methods: Web of Science and PubMed platforms were searched using appropriate key words. The review process resulted in 423 articles adherent to the search criteria, 28 of which were accepted and analysed. Web sites of all Portuguese governmental and non-governmental organisations, with a relevant role on the research topic, were inspected and 75 official documents were retrieved and analysed. Results: Since 2001, five regional screening programmes were gradually implemented under the guidelines of Portuguese General Health Department. However, complete population coverage was still not achieved. Among the main difficulties reported are the complex articulation between different levels of care providers, the low number of orthoptic technician in the national health system, the high burden that images grading, and treatment of positive cases represents for hospitals ophthalmology services, and low adherence rates. Yet, the comparison between strategies adopted in the different regions allowed the identification of potential solutions: hire orthoptic technician for primary health care units, eliminating the dependence of hospital professionals; use artificial intelligence algorithms for automatic retinographies grading, avoiding ophthalmologists overload; adoption of proximity strategies, as the use of portable retinographers, to promote adherence to screening. Conclusion: Access to diabetic retinopathy screening remains remarkably variable in Portugal and needs urgent attention. However, several characteristics of effective screening programmes were found in Portuguese screening programmes, what seems to point toward promising outcomes, especially if each other highlights are considered. The findings of this research could be very useful for the other countries with similar socio-political characteristics.info:eu-repo/semantics/publishedVersio

Differential relationships of childhood trauma and violent behaviour in adolescents with cognitive-emotional deficits

Konvergierende neurobiologische Studien zeigen, dass Negative Kindheitserfahrungen (Adverse Childhood Experiences, ACEs) mehrere dicht miteinander verknüpfte Hirnsysteme beeinflussen und die Entwicklung von Exekutivfunktionen stören, insbesondere die Fähigkeit, unangemessene Affekte und Handlungen zu unterdrücken. In der vorliegenden Arbeit wurde zunächst untersucht, wie Exekutivfunktionen in nicht-emotionalen (kühlen) und emotionalen (heißen) Situationen (d. h. Emotionsregulation) mit einer hohen Exposition gegenüber ACEs zusammenhängen und ob solche Beziehungen durch akuten Stress verstärkt werden. Unsere Ergebnisse zeigen, dass gewalttätiges Verhalten bei Opfern von Kindheitstraumata eher mit Defiziten in heißen Exekutivfunktionen als mit Defiziten in kühlen Exekutivfunktionen verbunden sein könnte, insbesondere unter Stressbedingungen. Insgesamt zeigt diese Studie erstens die Nützlichkeit von OpenFace, einem kostengünstigen und dennoch effektiven Instrument zur Untersuchung des mimischen Verhaltens bei der Emotionsregulation. Zweitens eröffnet sie Perspektiven für eine gezieltere Erforschung von und Interventionen bei ACEs. Drittens bezieht sie Jugendliche ein, eine wenig erforschte Altersgruppe, die sich in einer sensiblen Phase der Entwicklung von Exekutivfunktionen befinden.Converging neurobiological studies show that Adverse Childhood Experiences (ACEs) affect multiple densely interconnected neurobiological systems and disrupt the development of executive functions (EFs), especially the ability to inhibit inappropriate affects and actions, potentially modulating factors in the relationship between ACEs and violent behaviour. This study first sought to assess how EFs under non-emotional (cool) and emotional (hot) situations (i.e. emotion regulation) are related with high-exposure to ACEs, and whether any such relationships would be aggravated by acute stress. Our findings show that violent behavior among victims of childhood trauma might be associated more with deficits in hot EFs than it is with deficits in cool EFs, especially more so under conditions of stress. Altogether, this study first shows the usefulness of OpenFace, a low cost yet effective tool to study facial behaviour in emotion regulation. Second, it opens perspectives towards more targeted research on, and interventions for ACEs, and third, it involves adolescents, a little researched age group, yet a sensitive period of EFs development

The Iray Light Transport Simulation and Rendering System

While ray tracing has become increasingly common and path tracing is well understood by now, a major challenge lies in crafting an easy-to-use and efficient system implementing these technologies. Following a purely physically-based paradigm while still allowing for artistic workflows, the Iray light transport simulation and rendering system allows for rendering complex scenes by the push of a button and thus makes accurate light transport simulation widely available. In this document we discuss the challenges and implementation choices that follow from our primary design decisions, demonstrating that such a rendering system can be made a practical, scalable, and efficient real-world application that has been adopted by various companies across many fields and is in use by many industry professionals today

Laser interferometric measurement of ion electrode shape and charge exchange erosion

A projected fringe profilometry system was applied to surface contour measurements of an accelerator electrode from an ion thrustor. The system permitted noncontact, nondestructive evaluation of the fine and gross structure of the electrode. A 3-D surface map of a dished electrode was generated without altering the electrode surface. The same system was used to examine charge exchange erosion pits near the periphery of the electrode to determine the depth, location, and volume of material lost. This electro-optical measurement system allowed rapid, nondestructive, digital data acquisition coupled with automated computer data processing. In addition, variable sensitivity allowed both coarse and fine measurements of objects having various surface finishes

Bayesian Methods for Radiometric Calibration in Motion Picture Encoding Workflows

A method for estimating the Camera Response Function (CRF) of an electronic motion picture camera is presented in this work. The accurate estimation of the CRF allows for proper encoding of camera exposures into motion picture post-production workflows, like the Academy Color Encoding Specification (ACES), this being a necessary step to correctly combine images from different capture sources into one cohesive final production and minimize non-creative manual adjustments. Although there are well known standard CRFs implemented in typical video camera workflows, motion picture workflows and newer High Dynamic Range (HDR) imaging workflows have introduced new standard CRFs as well as custom and proprietary CRFs that need to be known for proper post-production encoding of the camera footage. Current methods to estimate this function rely on the use of measurement charts, using multiple static images taken under different exposures or lighting conditions, or assume a simplistic model of the function’s shape. All these methods become problematic and tough to fit into motion picture production and post-production workflows where the use of test charts and varying camera or scene setups becomes impractical and where a method based solely on camera footage, comprised of a single image or a series of images, would be advantageous. This work presents a methodology initially based on the work of Lin, Gu, Yamazaki and Shum that takes into account edge color mixtures in an image or image sequence, that are affected by the non-linearity introduced by a CRF. In addition, a novel feature based on image noise is introduced to overcome some of the limitations of edge color mixtures. These features provide information that is included in the likelihood probability distribution in a Bayesian framework to estimate the CRF as the expected value of a posterior probability distribution, which is itself approximated by a Markov Chain Monte Carlo (MCMC) sampling algorithm. This allows for a more complete description of the CRF over methods like Maximum Likelihood (ML) and Maximum A Posteriori (MAP). The CRF function is modeled by Principal Component Analysis (PCA) of the Database of Response Functions (DoRF) compiled by Grossberg and Nayar, and the prior probability distribution is modeled by a Gaussian Mixture Model (GMM) of the PCA coefficients for the responses in the DoRF. CRF estimation results are presented for an ARRI electronic motion picture camera, showing the improved estimation accuracy and practicality of this method over previous methods for motion picture post-production workflows