Abstract

International audience; Increasing the level of automation in air traffic management is seen as a measure to increase the performance of the service to satisfy the predicted future demand. This is expected to result in new roles for the human operator: he will mainly monitor highly automated systems and seldom intervene. Therefore, air traffic controllers (ATCos) would often work in a supervisory or control mode rather than in a direct operating mode. However, it has been demonstrated how human operators in such a role are affected by human performance issues, known as Out-Of-The-Loop (OOTL) phenomenon, consisting in lack of attention, loss of situational awareness and de-skilling. A countermeasure to this phenomenon has been identified in the adaptive automation (AA), i.e., a system able to allocate the operative tasks to the machine or to the operator depending on their needs. In this context, psychophysiological measures have been highlighted as powerful tool to provide a reliable, unobtrusive and real-time assessment of the ATCo’s mental state to be used as control logic for AA-based systems. In this paper, it is presented the so-called “Vigilance and Attention Controller”, a system based on electroencephalography (EEG) and eye-tracking (ET) techniques, aimed to assess in real time the vigilance level of an ATCo dealing with a highly automated human–machine interface and to use this measure to adapt the level of automation of the interface itself. The system has been tested on 14 professional ATCos performing two highly realistic scenarios, one with the system disabled and one with the system enabled. The results confirmed that (i) long high automated tasks induce vigilance decreasing and OOTL-related phenomena; (ii) EEG measures are sensitive to these kinds of mental impairments; and (iii) AA was able to counteract this negative effect by keeping the ATCo more involved within the operative task. The results were confirmed by EEG and ET measures as well as by performance and subjective ones, providing a clear example of potential applications and related benefits of AA. Document type: Article

Abstract

Air traffic controllers simultaneously develop complex and multiple tasks in the course of their activities. In this context, concern is raised over the high level of attention needed by these professionals which can ultimately be affected by stress and fatigue. Objectives: The objective of this study was to assess attention level in air traffic controllers (ATCo). Methods: 45 flight protection professionals were evaluated, comprising 30 ATCo, subdivided into ATCo with ten or more years in the profession (ATCo³10, n=15) and ATCo with less than ten years in the profession (ATCo "10, n=15) and 15 aeronautical information services operators (AIS), subdivided into AIS with ten years or more in the profession (AIS³10, n=8) and AIS with less than ten years in the profession (AIS "10, n=7), who were included as the control group. The digit symbol, d2 (the individual marks the letter d on a specific form containing 14 lines with 47 letters in each, maintaining focus on letter d followed by two dashes), forward digit span, backward digit span and PASAT (paced auditory serial addition test) attention tests were used. Kruskal-Wallis was used and data expressed as Median (Minimum and Maximum) with p"0.05. Results: The ATCo³10 presented greater focus of attention, sustained attention, mental manipulation and resistance to interference capacity compared to the AIS³10. Comparison of ATCo³10 to the AIS"10 showed they presented only greater resistance to interference, and when compared to the ATCo"10 presented lower focus. Conclusions: The air traffic control activity after ten years may be associated with a high level of attention. Resumo Os controladores de tráfego aéreo (CTA) desenvolvem em suas atividades tarefas complexas e múltiplas simultaneamente. Nesse contexto, surge a preocupação com a necessidade de um maior nível de atenção desses profissionais que pode ser afetada pelo estresse e fadiga. Objetivos: O objetivo deste trabalho foi avaliar o nível de atenção em controladores de tráfego aéreo (CTA). Métodos: Foram avaliados 45 profissionais de proteção ao vôo, sendo 30 CTA, subdivididos em CTA com dez ou mais anos na profissão (CTA³10, n=15) e CTA com menos de dez anos na profissão (CTA"10, n=15) e 15 operadores de serviços de informações aeronáuticas (AIS), subdivididos em AIS com dez anos ou mais na profissão (AIS³10, n=8) e AIS com menos de dez anos na profissão (AIS"10, n=7). Foram utilizados os testes de atenção digit symbol, d2 (o indivíduo deve marcar a letra d em um formulário específico, contendo 14 linhas com 47 letras cada, mantendo sempre o foco na letra d que aparece acompanhada de dois traços), span de dígitos em ordem direta e inversa e teste de dependência auditiva para adição em série (PASAT). Foi utilizado o Kruskal-Wallis e os dados expressos em mediana (mínimo e máximo), p"0,05. Resultados: Os CTA³10 apresentaram maior foco de atenção, manutenção do foco, capacidade de manipulação mental e resistência à interferência, quando comparados aos AIS³10, mas quando comparados aos AIS"10 apresentaram somente maior resistência à interferência e quando comparados aos CTA"10, menor foco. Conclusões: A atividade de controle de tráfego aéreo após dez anos pode apresentar um alto nível de atenção. Document type: Article

Abstract

Traffic congestion at bus bays has decreased the service efficiency of public transit seriously in China, so it is crucial to systematically study its theory and methods. However, the existing studies lack theoretical model on computing efficiency. Therefore, the calculation models of bus delay at bays are studied. Firstly, the process that buses are delayed at bays is analyzed, and it was found that the delay can be divided into entering delay and exiting delay. Secondly, the queueing models of bus bays are formed, and the equilibrium distribution functions are proposed by applying the embedded Markov chain to the traditional model of queuing theory in the steady state; then the calculation models of entering delay are derived at bays. Thirdly, the exiting delay is studied by using the queueing theory and the gap acceptance theory. Finally, the proposed models are validated using field-measured data, and then the influencing factors are discussed. With these models the delay is easily assessed knowing the characteristics of the dwell time distribution and traffic volume at the curb lane in different locations and different periods. It can provide basis for the efficiency evaluation of bus bays. Document type: Article

Abstract

Design concepts and algorithms were developed to address the eye tracking analysis issues that arise when (1) participants interrogate dynamic multielement objects that can overlap on the display and (2) visual angle error of the eye trackers is incapable of providing exact eye fixation coordinates. These issues were addressed by (1) developing dynamic areas of interests (AOIs) in the form of either convex or rectangular shapes to represent the moving and shape-changing multielement objects, (2) introducing the concept of AOI gap tolerance (AGT) that controls the size of the AOIs to address the overlapping and visual angle error issues, and (3) finding a near optimal AGT value. The approach was tested in the context of air traffic control (ATC) operations where air traffic controller specialists (ATCSs) interrogated multiple moving aircraft on a radar display to detect and control the aircraft for the purpose of maintaining safe and expeditious air transportation. In addition, we show how eye tracking analysis results can differ based on how we define dynamic AOIs to determine eye fixations on moving objects. The results serve as a framework to more accurately analyze eye tracking data and to better support the analysis of human performance. Document type: Article

Abstract

Background: Achieving clear visibility through a windshield is one of the crucial factors in manufacturing a safe and comfortable vehicle. The optic flow (OF) through the windshield has been reported to divert attention and could impair visibility. Although a growing number of behavioral and neuroimaging studies have assessed drivers' attention in various driving scenarios, there is still little evidence of a relationship between OF, windshield shape, and driver's attentional efficacy. The purpose of this research was to examine this relationship. Methods: First, we quantified the OF across the windshield in a simulated driving scenario with either of two types of the windshield (a tilted or vertical pillar) at different speeds (60 km/h or 160 km/h) and found more upward OF along the tilted pillar than along the vertical pillar. Therefore, we hypothesized that the predominance of upward OF around the windshield along a tilted pillar could distract a driver and that we could observe the corresponding neural activity. Magnetic resonance scans were then obtained while the subjects performed a visual detection task while watching the driving scene used in the OF analysis. The subjects were required to press a button as rapidly as possible when a target appeared at one of five positions (leftmost, left, center, right, and rightmost). Results: We found that the reaction time (RT) on exposure to a tilted pillar was longer than that on exposure to a vertical pillar in the leftmost and rightmost conditions. Furthermore, there was more brain activity in the precuneus when the pillar was tilted than when it was vertical in the rightmost condition near the pillar. In a separate analysis, activation in the precuneus was found to reflect relative changes in the amount of upward OF when the target was at the rightmost position. Conclusions: Overall, these observations suggest that activation in the precuneus may reflect extraneous cognitive load driven by upward OF along the pillar and could distract visual attention. The findings of this study highlight the value of a cognitive neuroscientific approach to research and development in the motor vehicle manufacturing industry. Document type: Article