The 4D-TECS integration for NASA TSRV airplane

The integration of the Total Energy Control System (TECS) concept with 4D navigation is described. This integration was made to increase the operational capacity of modern aircraft and encourage incorporation of this increased capability with the evolving National Airspace System (NAS). Described herein is: 4D smoothing, the basic concepts of TECS, the spoiler integration concept, an algorithm for nulling out time error, speed and altitude profile modes, manual spoiler implementation, 4D logic, and the results of linear and nonlinear analysis

Performance, Control, and Simulation of the Affordable Guided Airdrop System

This paper addresses the development of an autonomous guidance, navigation and control system for a flat solid circular parachute. This effort is a part of the Affordable Guided Airdrop System (AGAS) that integrates a low-cost guidance and control system into fielded cargo air delivery systems. The paper describes the AGAS concept, its architecture and components. It then reviews the literature on circular parachute modeling and introduces a simplified model of a parachute. This model is used to develop and evaluate the performance of a modified bang-bang control system to steer the AGAS along a pre-specified trajectory towards a desired landing point. The synthesis of the optimal control strategy based on Pontryagin's principle of optimality is also presented. The paper is intended to be a summary of the current state of AGAS development. The paper ends with the summary of the future plans in this area

From attosecond to zeptosecond coherent control of free-electron wave functions using semi-infinite light fields

Light-electron interaction in empty space is the seminal ingredient for free-electron lasers and also for controlling electron beams to dynamically investigate materials and molecules. Pushing the coherent control of free electrons by light to unexplored timescales, below the attosecond, would enable unprecedented applications in light-assisted electron quantum circuits and diagnostics at extremely small timescales, such as those governing intramolecular electronic motion and nuclear phenomena. We experimentally demonstrate attosecond coherent manipulation of the electron wave function in a transmission electron microscope, and show that it can be pushed down to the zeptosecond regime with existing technology. We make a relativistic pulsed electron beam interact in free space with an appropriately synthesized semi-infinite light field generated by two femtosecond laser pulses reflected at the surface of a mirror and delayed by fractions of the optical cycle. The amplitude and phase of the resulting coherent oscillations of the electron states in energymomentum space are mapped via momentum-resolved ultrafast electron energy-loss spectroscopy. The experimental results are in full agreement with our theoretical framework for light-electron interaction, which predicts access to the zeptosecond timescale by combining semi-infinite X-ray fields with free electrons.Comment: 22 pages, 6 figure

Sending femtosecond pulses in circles: highly non-paraxial accelerating beams

We use caustic beam shaping on 100 fs pulses to experimentally generate non-paraxial accelerating beams along a 60 degree circular arc, moving laterally by 14 \mum over a 28 \mum propagation length. This is the highest degree of transverse acceleration reported to our knowledge. Using diffraction integral theory and numerical beam propagation simulations, we show that circular acceleration trajectories represent a unique class of non-paraxial diffraction-free beam profile which also preserves the femtosecond temporal structure in the vicinity of the caustic

One-Dimensional “Ghost Imaging” in Electron Microscopy of Inelastically Scattered Electrons

Entanglement and correlation are at the basis of quantum mechanics and have been used in optics to create a framework for “ghost imaging”. We propose that a similar scheme can be used in an electron microscope to exploit the correlation of electrons with the coincident detection of collective mode excitations in a sample. In this way, an image of the sample can be formed on an electron camera even if electrons never illuminated the region of interest directly. This concept, which can be regarded as the inverse of photon-induced near-field electron microscopy, can be used to probe delicate molecules with a resolution that is beyond the wavelength of the collective mode

Distorted maternal mental representations and atypical behavior in a clinical sample of violence-exposed mothers and their toddlers

Objective: To determine whether maternal violence-related posttraumatic stress disorder (PTSD), reflective functioning (RF), and/or quality of mental representations of her child predicts maternal behavior within a referred sample of mothers exposed to interpersonal violence and their children (aged 8–50 months). Method: A total of 41 dyads completed 2 videotaped visits including measures of maternal mentalrepresentations and behavior. Results: Negative and distorted maternal mental representations predicted atypical behavior (Cohen’s d \u3e 1.0). Although maternal PTSD and RF impacted mental representations, no significant relationships were found between PTSD, RF, and overall atypical caregiving behavior. Severity of maternal PTSD was, however, positively correlated with the avoidant caregiving behaviorsubscale. Conclusions: Maternal mental representations of her child are useful risk indicators that mark dysregulation of trauma-associated emotions in the caregiver

Learning to Communicate: A Machine Learning Framework for Heterogeneous Multi-Agent Robotic Systems

We present a machine learning framework for multi-agent systems to learn both the optimal policy for maximizing the rewards and the encoding of the high dimensional visual observation. The encoding is useful for sharing local visual observations with other agents under communication resource constraints. The actor-encoder encodes the raw images and chooses an action based on local observations and messages sent by the other agents. The machine learning agent generates not only an actuator command to the physical device, but also a communication message to the other agents. We formulate a reinforcement learning problem, which extends the action space to consider the communication action as well. The feasibility of the reinforcement learning framework is demonstrated using a 3D simulation environment with two collaborating agents. The environment provides realistic visual observations to be used and shared between the two agents.Comment: AIAA SciTech 201

Interpersonal violence: an important risk factor for disease and injury in South Africa

<p>Abstract</p> <p>Background</p> <p>Burden of disease estimates for South Africa have highlighted the particularly high rates of injuries related to interpersonal violence compared with other regions of the world, but these figures tell only part of the story. In addition to direct physical injury, violence survivors are at an increased risk of a wide range of psychological and behavioral problems. This study aimed to comprehensively quantify the excess disease burden attributable to exposure to interpersonal violence as a risk factor for disease and injury in South Africa.</p> <p>Methods</p> <p>The World Health Organization framework of interpersonal violence was adapted. Physical injury mortality and disability were categorically attributed to interpersonal violence. In addition, exposure to child sexual abuse and intimate partner violence, subcategories of interpersonal violence, were treated as risk factors for disease and injury using counterfactual estimation and comparative risk assessment methods. Adjustments were made to account for the combined exposure state of having experienced both child sexual abuse and intimate partner violence.</p> <p>Results</p> <p>Of the 17 risk factors included in the South African Comparative Risk Assessment study, interpersonal violence was the second leading cause of healthy years of life lost, after unsafe sex, accounting for 1.7 million disability-adjusted life years (DALYs) or 10.5% of all DALYs (95% uncertainty interval: 8.5%-12.5%) in 2000. In women, intimate partner violence accounted for 50% and child sexual abuse for 32% of the total attributable DALYs.</p> <p>Conclusions</p> <p>The implications of our findings are that estimates that include only the direct injury burden seriously underrepresent the full health impact of interpersonal violence. Violence is an important direct and indirect cause of health loss and should be recognized as a priority health problem as well as a human rights and social issue. This study highlights the difficulties in measuring the disease burden from interpersonal violence as a risk factor and the need to improve the epidemiological data on the prevalence and risks for the different forms of interpersonal violence to complete the picture. Given the extent of the burden, it is essential that innovative research be supported to identify social policy and other interventions that address both the individual and societal aspects of violence.</p

Levels of resilience and delivery of HIV care in response to urban violence and crime

Aims To understand the impact of urban violence and crime on HIV care delivery. Background Urban violence and crime can put pressure on the health care system and on nursing staff. Whilst the impact this has at the individual level has been researched, there is less research that places this within the context of the overall social eco system. Design A qualitative design using inductive thematic analysis. Methods Between July 2016 February 2017, in‐depth interviews were conducted with 10 nurses working in two neighbourhoods with high levels of violence in Cape Town, South Africa. Results The effects of crime and violence were evident at multiple levels resulting in participants feeling ‘safe and unsafe’ in a context where crime is viewed as endemic. Resilience emerged as a key concept in the findings. Resilience was apparent at individual, community and organizational levels and enabled continued delivery of HIV care. Conclusion The findings demonstrate the potential role of resilience within the social eco‐health system required to sustain delivery of HIV care in the midst of urban violence and gangsterism. Impact This study examined the impact of and response to urban violence on HIV care delivery. The findings indicate that resilience manifests at all levels of the social eco‐system. Understanding the mechanisms employed to cope with endemic violence helps to address these challenges in the study setting, but also has a much wider application to other areas with endemic urban violence and crime