Attentional Resource Demands of Traditional and Novel Instrument Landing Systems

A peripherally-located optical flow (POF) instrument landing system (ILS) display affords greater flight performance and sensitivity to a concurrent visual signal detection task, as compared to the display specified by Mil-Std 1787B. This study examined whether such an advantage extends to auditory secondary tasks. During a simulated approach and landing task participants maneuvered an aircraft along a predetermined glide path using either a peripherally-located optical flow instrument landing system or the Mil-Std 1787B landing system. Participants concurrently performed a visual or auditory signal detection task. Participant flight performance and signal detection task sensitivity were measures of the task time-sharing efficiency afforded by the ILS display. The visual task required participants to monitor two engines and identify the simultaneous occurrence of two critical conditions. The auditory task required participants to detect the sequential presentation of an assigned call sign and command line during a stream of call signs and command lines. Sensitivity in visual and auditory monitoring was assessed using the signal detection parameter A, while glide-path deviations served as the measure of landing performance. The mean performance of the flight control task by instrument landing display type matched performance patterns from previous studies. Visual signal detection performance improved while using the POF ILS for the flight task, suggesting a lower visual resource demand in comparison to the Mil-Std ILS. Display type did not affect auditory signal detection task performance. Since the auditory task is similarly affected by both displays in the flight control task but the visual task is more impacted by the Mil-Std display, we conclude the POF ILS imposes a central resource demand like the Mil-Std display but without the same visual processing demands.masters, M.S., Psychology -- University of Idaho - College of Graduate Studies, 2017-1

Peripherally-Located Virtual Instrument Landing Displays

We examined how the location and spatial extent of a peripherally-located virtual instrument landing system (ILS) head-up display (HUD) affects landing precision. Our experiment compared three spatial formats of a peripherally-located virtual ILS HUD: a) a large-format display located within rectangular regions defined relative to the center of the HUD, with the lateral flight indicator subtending +/-5 to 62.5° by +/-0 to 16.875° (HxV) and the vertical flight command indicator subtending +/-0 to 45° by +/-6.875 to 16.875° (HxV); b) near-peripheral displays comprised of roughly the inner half of the large format display; and c) far-peripheral displays, comprised of the remaining outer half. We found that restricting display locations and extents to either the near or far periphery provided landing precision statistically equivalent to the largeformat displays, which suggests that HUD clutter could be reduced by moving virtual ILS displays into the far periphery without negatively impacting landing precision

Evaluation of a Peripherally-Located Instrument Landing Display Under Dual-Task Conditions

Previous research found that a peripherally-located instrument landing system (ILS) embedded in a head-up display (HUD) supported equal or better control of glide-path during simulated approach and landing than the traditional centrally-located MIL-STD ILS. Here, we used a dualtask paradigm to examine whether gains in landing precision with the peripheral ILS are also accompanied by a reduction in mental workload. Participants controlled glide-path during simulated instrument landings while simultaneously performing a secondary task monitoring a head-down engine display for fault states. We varied the type of ILS (peripheral vs. MIL-STD) and assessed mental workload using the NASA-TLX and primary and secondary task performance measures: glide-path errors and engine-fault detection sensitivity, respectively. We found equivalent glide-path errors for the two displays, but the peripheral ILS produced lower subjective estimates of mental workload and significantly less dual-task decrement in engine-monitoring sensitivity, indicating that this display affords effective glide-path control with lower reduced mental demand

Modeling and Detecting Community Hierarchies

Abstract. Community detection has in recent years emerged as an invaluable tool for describing and quantifying interactions in networks. In this paper we propose a theoretical model that explicitly formalizes both the tight connections within each community and the hierarchical nature of the communities. We further present an efficient algorithm that provably detects all the communities in our model. Experiments demonstrate that our definition successfully models real world communities, and our algorithm compares favorably with existing approaches

Local clustering of large graphs by approximate Fiedler vectors

Abstract We address the problem of determining the natural neighbourhood of a given node i in a large nonunifom network G in a way that uses only local computations, i.e. without recourse to the full adjacency matrix of G. We view the problem as that of computing potential values in a diffusive system where node i is fixed at zero potential, and the potentials at the other nodes are then induced by the adjacency relation of G. This point of view leads to a constrained spectral clustering approach. We observe that a gradient method for computing the respective Fiedler vector values at each node can be implemented in a local manner, leading to our eventual algorithm. The algorithm is evaluated experimentally using two types of nonuniform networks: randomised “caveman graphs ” and a scientific collaboration network.

Design of graph filters and filterbanks

International audienceBasic operations in graph signal processing consist in processing signals indexed on graphs either by filtering them or by changing their domain of representation, in order to better extract or analyze the important information they contain. The aim of this chapter is to review general concepts underlying such filters and representations of graph signals. We first recall the different Graph Fourier Transforms that have been developed in the literature, and show how to introduce a notion of frequency analysis for graph signals by looking at their variations. Then, we move to the introduction of graph filters, that are defined like the classical equivalent for 1D signals or 2D images, as linear systems which operate on each frequency of a signal. Some examples of filters and of their implementations are given. Finally, as alternate representations of graph signals, we focus on multiscale transforms that are defined from filters. Continuous multiscale transforms such as spectral wavelets on graphs are reviewed, as well as the versatileapproaches of filterbanks on graphs. Several variants of graph filterbanks are discussed, for structured as well as arbitrary graphs, with a focus on the central point of the choice of the decimation or aggregation operators