1,845 research outputs found
Declutter and Resample: Towards parameter free denoising
In many data analysis applications the following scenario is commonplace: we
are given a point set that is supposed to sample a hidden ground truth in a
metric space, but it got corrupted with noise so that some of the data points
lie far away from creating outliers also termed as {\em ambient noise}. One
of the main goals of denoising algorithms is to eliminate such noise so that
the curated data lie within a bounded Hausdorff distance of . Popular
denoising approaches such as deconvolution and thresholding often require the
user to set several parameters and/or to choose an appropriate noise model
while guaranteeing only asymptotic convergence. Our goal is to lighten this
burden as much as possible while ensuring theoretical guarantees in all cases.
Specifically, first, we propose a simple denoising algorithm that requires
only a single parameter but provides a theoretical guarantee on the quality of
the output on general input points. We argue that this single parameter cannot
be avoided. We next present a simple algorithm that avoids even this parameter
by paying for it with a slight strengthening of the sampling condition on the
input points which is not unrealistic. We also provide some preliminary
empirical evidence that our algorithms are effective in practice
Going Below Minimums: The Efficacy of Display Enhanced/Synthetic Vision Fusion for Go-Around Decisions during Non-Normal Operations
The use of enhanced vision systems in civil aircraft is projected to increase rapidly as the Federal Aviation Administration recently changed the aircraft operating rules under Part 91, revising the flight visibility requirements for conducting approach and landing operations. Operators conducting straight-in instrument approach procedures may now operate below the published approach minimums when using an approved enhanced flight vision system that shows the required visual references on the pilot's Head-Up Display. An experiment was conducted to evaluate the complementary use of synthetic vision systems and enhanced vision system technologies, focusing on new techniques for integration and/or fusion of synthetic and enhanced vision technologies and crew resource management while operating under these newly adopted rules. Experimental results specific to flight crew response to non-normal events using the fused synthetic/enhanced vision system are presented
Commercial Flight Crew Decision-Making during Low-Visibility Approach Operations Using Fused Synthetic/Enhanced Vision Systems
NASA is investigating revolutionary crew-vehicle interface technologies that strive to proactively overcome aircraft safety barriers that would otherwise constrain the full realization of the next-generation air transportation system. A fixed-based piloted simulation experiment was conducted to evaluate the complementary use of Synthetic and Enhanced Vision technologies. Specific focus was placed on new techniques for integration and/or fusion of Enhanced and Synthetic Vision and its impact within a two-crew flight deck on the crew's decision-making process during low-visibility approach and landing operations. Overall, the experimental data showed that significant improvements in situation awareness, without concomitant increases in workload and display clutter, could be provided by the integration and/or fusion of synthetic and enhanced vision technologies for the pilot-flying and the pilot-not-flying. During non-normal operations, the ability of the crew to handle substantial navigational errors and runway incursions were neither improved nor adversely impacted by the display concepts. The addition of Enhanced Vision may not, unto itself, provide an improvement in runway incursion detection without being specifically tailored for this application. Existing enhanced vision system procedures were effectively used in the crew decision-making process during approach and missed approach operations but having to forcibly transition from an excellent FLIR image to natural vision by 100 ft above field level was awkward for the pilot-flying
The Traffic-Alert and Collision Avoidance System (TCAS) in the glass cockpit
This volume contains the contributions of the participants in the NASA Ames Research Center workshop on the traffic-alert and collision avoidance system (TCAS) implementation for aircraft with cathode ray tube (CRT) or flat panel displays. To take advantage of the display capability of the advanced-technology aircraft, NASA sponsored this workshop with the intent of bringing together industry personnel, pilots, and researchers so that pertinent issues in the area could be identified. During the 2-day workshop participants addressed a number of issues including: What is the optimum format for TCAS advisories. Where and how should maneuver advisories be presented to the crew. Should the maneuver advisories be presented on the primary flight display. Is it appropriate to have the autopilot perform the avoidance maneuver. Where and how should traffic information be presented to the crew. Should traffic information be combined with weather and navigation information. How much traffic should be shown and what ranges should be used. Contained in the document are the concepts and suggestions produced by the workshop participants
Social work intervention with adults who self-neglect in England: responding to the Care Act 2014
Purpose – The paper reports on findings from an evaluative research study which looked at a timed intervention model of practice comprising of up to 24 weeks of intensive meetings with adult service users set up by one local authority in England, to prevent and delay the need for care and support. A particular focus of this paper is adults who hoard. Design/methodology/approach – The study employed a mixed-methods design, consisting of interviews with service users (n=13); social workers (n=3); social work managers (n=2); and stakeholders from external services and agencies (n=6). It included a costings analysis of staff time and an analysis of service users’ goals and of ‘satisfaction with life’ self-report questionnaires (n=20), completed at pre- and post-intervention stages. Findings – There was evidence that social workers used strengths, relationship-based and outcome-focused approaches in their work. The techniques used by social workers to engage, achieve change and assess effectiveness with service users varied. These included the use of photographs to enable the service user to map and assess their own progress over time, encouraging hoarders to declutter and reclaim their living space. The service users valued the time the social workers spent with them and the way that they were treated with sensitivity and respect. Research limitations/implications – The study focused on one local authority in England; there was no comparison group. This, and the small sample size, means that statistical generalisations cannot be made and only limited conclusions can be drawn from the quantitative data
Crew and Display Concepts Evaluation for Synthetic / Enhanced Vision Systems
NASA s Synthetic Vision Systems (SVS) project is developing technologies with practical applications that strive to eliminate low-visibility conditions as a causal factor to civil aircraft accidents and replicate the operational benefits of clear day flight operations, regardless of the actual outside visibility condition. Enhanced Vision System (EVS) technologies are analogous and complementary in many respects to SVS, with the principle difference being that EVS is an imaging sensor presentation, as opposed to a database-derived image. The use of EVS in civil aircraft is projected to increase rapidly as the Federal Aviation Administration recently changed the aircraft operating rules under Part 91, revising the flight visibility requirements for conducting operations to civil airports. Operators conducting straight-in instrument approach procedures may now operate below the published approach minimums when using an approved EVS that shows the required visual references on the pilot s Head-Up Display. An experiment was conducted to evaluate the complementary use of SVS and EVS technologies, specifically focusing on new techniques for integration and/or fusion of synthetic and enhanced vision technologies and crew resource management while operating under the newly adopted FAA rules which provide operating credit for EVS. Overall, the experimental data showed that significant improvements in SA without concomitant increases in workload and display clutter could be provided by the integration and/or fusion of synthetic and enhanced vision technologies for the pilot-flying and the pilot-not-flying
Aspects of Synthetic Vision Display Systems and the Best Practices of the NASA's SVS Project
NASA s Synthetic Vision Systems (SVS) Project conducted research aimed at eliminating visibility-induced errors and low visibility conditions as causal factors in civil aircraft accidents while enabling the operational benefits of clear day flight operations regardless of actual outside visibility. SVS takes advantage of many enabling technologies to achieve this capability including, for example, the Global Positioning System (GPS), data links, radar, imaging sensors, geospatial databases, advanced display media and three dimensional video graphics processors. Integration of these technologies to achieve the SVS concept provides pilots with high-integrity information that improves situational awareness with respect to terrain, obstacles, traffic, and flight path. This paper attempts to emphasize the system aspects of SVS - true systems, rather than just terrain on a flight display - and to document from an historical viewpoint many of the best practices that evolved during the SVS Project from the perspective of some of the NASA researchers most heavily involved in its execution. The Integrated SVS Concepts are envisagements of what production-grade Synthetic Vision systems might, or perhaps should, be in order to provide the desired functional capabilities that eliminate low visibility as a causal factor to accidents and enable clear-day operational benefits regardless of visibility conditions
Gaze modulated disambiguation technique for gesture control in 3D virtual objects selection
© 2017 IEEE. Inputs with multimodal information provide more natural ways to interact with virtual 3D environment. An emerging technique that integrates gaze modulated pointing with mid-air gesture control enables fast target acquisition and rich control expressions. The performance of this technique relies on the eye tracking accuracy which is not comparable with the traditional pointing techniques (e.g., mouse) yet. This will cause troubles when fine grainy interactions are required, such as selecting in a dense virtual scene where proximity and occlusion are prone to occur. This paper proposes a coarse-to-fine solution to compensate the degradation introduced by eye tracking inaccuracy using a gaze cone to detect ambiguity and then a gaze probe for decluttering. It is tested in a comparative experiment which involves 12 participants with 3240 runs. The results show that the proposed technique enhanced the selection accuracy and user experience but it is still with a potential to be improved in efficiency. This study contributes to providing a robust multimodal interface design supported by both eye tracking and mid-air gesture control
Factorization of Seiberg-Witten Curves and Compactification to Three Dimensions
We continue our study of nonperturbative superpotentials of four-dimensional
N=2 supersymmetric gauge theories with gauge group U(N) on R^3 x S^1, broken to
N=1 due to a classical superpotential. In a previous paper, hep-th/0304061, we
discussed how the low-energy quantum superpotential can be obtained by
substituting the Lax matrix of the underlying integrable system directly into
the classical superpotential. In this paper we prove algebraically that this
recipe yields the correct factorization of the Seiberg-Witten curves, which is
an important check of the conjecture. We will also give an independent proof
using the algebraic-geometrical interpretation of the underlying integrable
system.Comment: laTeX, 14 pages, uses AMSmat
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