Cognitive process modelling of controllers in en route air traffic control

In recent years, various efforts have been made in air traffic control (ATC) to maintain traffic safety and efficiency in the face of increasing air traffic demands. ATC is a complex process that depends to a large degree on human capabilities, and so understanding how controllers carry out their tasks is an important issue in the design and development of ATC systems. In particular, the human factor is considered to be a serious problem in ATC safety and has been identified as a causal factor in both major and minor incidents. There is, therefore, a need to analyse the mechanisms by which errors occur due to complex factors and to develop systems that can deal with these errors. From the cognitive process perspective, it is essential that system developers have an understanding of the more complex working processes that involve the cooperative work of multiple controllers. Distributed cognition is a methodological framework for analysing cognitive processes that span multiple actors mediated by technology. In this research, we attempt to analyse and model interactions that take place in en route ATC systems based on distributed cognition. We examine the functional problems in an ATC system from a human factors perspective, and conclude by identifying certain measures by which to address these problems. This research focuses on the analysis of air traffic controllers' tasks for en route ATC and modelling controllers' cognitive processes. PRACTITIONER SUMMARY: This research focuses on an experimental study to gain a better understanding of controllers' cognitive processes in air traffic control. We conducted ethnographic observations and then analysed the data to develop a model of controllers' cognitive process. This analysis revealed that strategic routines are applicable to decision making.     

An observation tool to study air traffic control and flightdeck collaboration

The complex systems of the flightdeck (FD) and the Air Traffic Control Centre (ATC) are characterised by numerous concurrently operating and interacting communication channels between people and between people and machines/computer systems. This paper describes work in support of investigating the impact of changes to technologies and responsibilities within this system with respect to human factors. It focuses primarily on the introduction of datalink (text-based communication rather than traditional radio communication) and the move towards freeflight (pilot-mediated air traffic control). Air traffic management investigations have outlined these specific changes as strategies to enable further increases in the volume of air traffic. A systems approach was taken and field studies were conducted. Small numbers of domain experts such as air traffic controllers (ATCOs) were involved in the field-based observations of how people interact with systems and each other. This paper summarises the overall research approach taken and then specifically reports on the field-based observations including the justification, development, and findings of the observation tool used. The observation tool examined information propagation through the air traffic control-flightdeck (ATC-FD) system, and resulted in models of possible information trajectories through the system.     

From crisis to development--analysis of air traffic control work processes

In this study an intervention to improve work processes in air traffic control (ATC) is evaluated. The background was the Finnish air traffic controllers’ strike of 1999. The old ways of thinking and acting did not support development of ATC prompting a need for a new kind of working culture in the organisation. Several actions were started. In one of these, ATC work processes were modelled by personnel and development plans concerning work were delivered to top management. Different actors (management, trade union, stakeholders) were interviewed before (n = 16) and after the project (n = 7). The intervention supported systematic co-operation between different actors in the organisation. However, a follow-up revealed that only a few participants had adopted the idea of continuous work development. Mastery of human factors is crucial in a high reliability work environment such as ATC. But how is the analytical and co-operative aspect kept alive in an organisation that is run by strict international regulation and has a strong technical competence, but is not that strong in collaborative and human aspects?     

Analysis of the performance characteristics of controllers’ strategies in en route air traffic control tasks

For addressing human factor issues in the air traffic control (ATC) domain, further comprehension of controllers’ working methods during actual work is required. The objective of the present research is to analyze the performance characteristics of control strategies, which can be a major means to manage a traffic situation and workload for controllers, by using our process visualization tool of ATC tasks called COMPASi (COMPAS in interactive mode/COMPAS: COgnitive system Model for simulating Projection-based behaviors of Air traffic controllers in dynamic Situations). The computer-based simulation using COMPASi has clearly demonstrated the performance differences in the types of control strategies derived from a high-fidelity human-in-the-loop simulation (HITLS) for safety, efficiency of completing ATC tasks, and fuel economy of aircraft in a specific situation, and also differences in their tolerance of situational variability. The analysis results have been supported by performance evaluations carried out by ATC training instructors. In addition, a comparative analysis between simulation results under several simulation conditions by COMPASi and evaluation results by the instructor has strongly implied that the tolerance for the variability of situations might be a major factor in selection of control strategies by a controller. These contributions of the present research may be useful for practical purposes such as further improvement of education and training for controllers.     

Flightdeck and air traffic control collaboration evaluation (FACE): evaluating aviation communication in the laboratory and field

The challenge to anticipate the human factors impact of introducing new technologies into a safety critical environment can be addressed in a number of ways. This paper presents a research programme that utilised both laboratory- and field-based assessments to examine the way in which datalink and freeflight may affect the communication and collaboration between pilots, air traffic controllers, and other actors and artefacts in the flightdeck-air traffic control (ATC) joint cognitive system. An overview of the results from these studies is presented, and guidance is provided as to the likely situations in which this new technology is most likely to be successfully applied. In addition, the methodological approach of combining results from field and laboratory data is discussed.     

Multifactor interactions and the air traffic controller: the interaction of situation awareness and workload in association with automation

Air traffic controllers must maintain a consistently high level of human performance in order to maintain flight safety and efficiency. In current control environments, performance-influencing factors such as workload, fatigue and situation awareness can co-occur and interact to affect performance. However, multifactor influences and the association with performance are under-researched. This study utilised a high-fidelity, human-in-the-loop, en route air traffic control simulation to investigate the relationship between workload, situation awareness and controller performance. The current study aimed to replicate Edwards et al.’s (in: Proceedings of the 4th AHFE international conference, 21–25th July, San Francisco, USA, 2012) previous finding that factors known to be associated with controller performance do co-vary and can interact, which is associated with a compound influence on performance. In addition, the current study aimed to extend Edwards et al.’s (2012) study by engaging retired controllers as participants and comparing multifactor relationships across four levels of automation. Results suggest that workload and situation awareness may interact to produce a compound (as opposed to cumulative) impact on controller performance. In addition, the effect of the interaction on performance may be dependent on the context and level of automation. Findings have implications for human–automation teaming in air traffic control, and the potential prediction of performance-influencing situations, supporting controller performance in the operational environment.     

Modeling and predicting mental workload in en route air traffic control: critical review and broader implications

OBJECTIVE: We perform a critical review of research on mental workload in en route air traffic control (ATC). We present a model of operator strategic behavior and workload management through which workload can be predicted within ATC and other complex work systems. BACKGROUND: Air traffic volume is increasing worldwide. If air traffic management organizations are to meet future demand safely, better models of controller workload are needed. METHOD: We present the theoretical model and then review investigations of how effectively traffic factors, airspace factors, and operational constraints predict controller workload. RESULTS: Although task demand has a strong relationship with workload, evidence suggests that the relationship depends on the capacity of the controllers to select priorities, manage their cognitive resources, and regulate their own performance. We review research on strategies employed by controllers to minimize the control activity and information-processing requirements of control tasks. CONCLUSION: Controller workload will not be effectively modeled until controllers' strategies for regulating the cognitive impact of task demand have been modeled. APPLICATION: Actual and potential applications of our conclusions include a reorientation of workload modeling in complex work systems to capture the dynamic and adaptive nature of the operator's work. Models based around workload regulation may be more useful in helping management organizations adapt to future control regimens in complex work systems.     

Comparisons of air traffic control implementations on an associative processor with a MIMD and consequences for parallel computing

This paper has two complementary focuses. The first is the system design and algorithmic development for air traffic control (ATC) using an associative SIMD processor (AP). The second is the comparison of this implementation with a multiprocessor implementation and the implications of these comparisons. This paper demonstrates how one application, ATC, can more easily, more simply, and more efficiently be implemented on an AP than is generally possible on other types of traditional hardware. The AP implementation of ATC will take advantage of its deterministic hardware to use static scheduling. The software will be dramatically smaller and cheaper to create and maintain. Likewise, a large AP system will be considerably simpler and cheaper than the MIMD hardware currently used. While APs were used for ATC-type applications earlier, these are no longer available. We use a ClearSpeed CSX600 accelerator to emulate the AP solutions of ATC on an ATC prototype consisting of eight data-intensive ATC real-time tasks. Its performance is compared with an 8-core multiprocessor (MP) using OpenMP. Our extensive experiments show that the AP implementation meets all deadlines while the MP will regularly miss a large number of deadlines. The AP code will be similar in size to sequential code for the same tasks and will avoid all of the additional support software needed with an MP to handle dynamic scheduling, load balancing, shared resource management, race conditions, false sharing, etc. At this point, essentially only MIMD systems are built. Many of the advantages of using an AP to solve an ATC problem would carry over to other applications. AP solutions for a wide variety of applications will be cited in this paper. Applications that involve a high degree of data parallelism such as database management, text processing, image processing, graph processing, bioinformatics, weather modeling, managing UAS (Unmanned Aircraft Systems or drones) etc., are good candidates for AP solutions. This raises the issue of whether we should routinely consider using non-multiprocessor hardware like the AP for applications where substantially simpler software solutions will normally exist. It also raises the question of whether the use of both AP and MIMD hardware in a single hetergeneous system could provide more versatility and efficiency. Either the AP or MIMD could serve as the primary system, but could hand off jobs it could not handle efficiently to the other system.     

浅析空管自动化系统的软件质量保证

从软件开发、质量控制过程的角度分析和探讨了国产空管自动化系统在研制过程中软件的质量形成过程,包括过程控制和软件测试流程,同时分析了影响空管软件质量的因素.     

A visualization tool of en route air traffic control tasks for describing controller’s proactive management of traffic situations

Improvements of aviation systems are now in progress to ensure the safety and efficiency of air transport in response to the rapid growth of air traffic. For providing theoretical and empirical basis for design and evaluation of aviation systems, researches focusing on cognitive aspects of air traffic controllers are definitely important. Whereas various researches from cognitive perspective have been performed in the Air Traffic Control (ATC) domain, there are few researches trying to illustrate ATCO’s control strategies and their effects on task demands in real work situations. The authors believe that findings from these researches can contribute to reveal why ATCOs are capable of handling air traffic safely and efficiently even in the high-density traffic condition. It can be core knowledge for tackling human factors issues in the ATC domain such as development of further effective education and training program of ATCO trainees. However, it is difficult to perform such kinds of researches because identification of ATC task from a given traffic situation and specification of effects of ATCO’s control strategies on task demands requires expert knowledge of ATCOs. The present research therefore aims at developing an automated identification and visualization tool of en route ATC tasks based on a cognitive system simulation of an en route controller called COMPAS (COgnitive system Model for simulating Projection-based behaviors of Air traffic controller in dynamic Situations), developed by the authors. The developed visualization tool named COMPASⁱ (COMPAS in interactive mode) equips a projection process model that can simulate realistic features of ATCO’s projection involving setting extra margins for errors of projection. The model enables COMPASⁱ to detect ATC tasks in a given traffic situation automatically and to identify Task Demand Level (TDL), that is, an ATC task index. The basic validity of COMPASⁱ has been confirmed through detailed comparison between TDLs given by a training instructor and ones by COMPASⁱ in a simulation-based experiment. Since TDL corresponds to demands of ATC tasks, temporal sequences of TDLs can reflect effectiveness of ATCO’s control strategies in terms of regulating task demands. By accumulation and analysis of such kind of data, it may be expected to reveal important aspect of ATCO’s skill for achieving the safety and efficiency of air traffic.     

Determinants of conflict detection: a model of risk judgments in air traffic control

OBJECTIVE: A model of conflict judgments in air traffic control (ATC) is proposed. BACKGROUND: Three horizontal distances determine risk judgments about conflict between two aircraft: (a) Dt(o) is the distance between the crossing of the aircraft trajectories and the first aircraft to reach that point; (b) Dt(h) is the distance between the two aircraft when they are horizontally closest; and (c) Dt(v) is the horizontal distance between the two aircraft when their growing vertical distance reaches 1000 feet. METHODS: Two experiments tested whether the variables in the model reflect what controllers do. In Experiment 1, 125 certified controllers provided risk judgments about situations in which the model variables were manipulated. Experiment 2 investigated the relationship between the model and expertise by comparing a population of certified controllers with a population of ATC students. RESULTS: Across both experiments, the model accounted for 44% to 50% of the variance in risk judgments by certified controllers (N=161) but only 20% in judgments by ATC students (N=88). There were major individual differences in the predictive power of the model as well as in the contributions of the three variables. In Experiment 2, the model described experts better than novices. CONCLUSION: The model provided a satisfying account of the data, albeit with substantial individual differences. It is argued that an individual-differences approach is required when investigating the strategies involved in conflict judgment in ATC. APPLICATION: These findings should have implications for developing user-friendly interfaces with conflict detection devices and for devising ATC training programs.     

Application of HFACS and grounded theory for identifying risk factors of air traffic controllers’ unsafe acts

Unsafe acts of air traffic controllers (ATCers) are caused by various factors. Based on interview data and case reports, human factors analysis and classification system (HFACS) and the grounded theory were adopted to identify the risk factors of ATCers’ unsafe acts comprehensively. The interview data and the case data issued by the authority were first collected. Then, the above data were encoded to obtain the relevant concepts and categories based on the grounded theory, and the HFACS model is used to classify the concepts and categories. Finally, the relationship between the core category and the secondary category was sorted out in the way of storyline. The results show that the risk factors include environmental factors, organizational influences, unsafe supervision and controllers’ states, and the unsafe acts manifest as errors and violations. Among them, the controllers’ states are intermediate variable, and other factors indirectly affect the controllers’ unsafe acts. The first three risk factors with high frequency in unsafe incidents are technical environment, mental states and business ability. The three most common unsafe acts are giving the wrong order, insufficient situational awareness, and poor work order on-site. Through combining HFACS framework and grounded theory to analyze data, a more clear and comprehensive conceptual model of risk factors of ATCers’ unsafe acts can be obtained.     

ATC数字语音通讯模拟系统的设计与实现

设计和实现了一种基于客户／服务器架构和IP协议的全数字信号传输语音通讯模拟系统。系统采用电台的通讯方式实现了一对多半双工通话,采用拨号电话的通讯方式实现了点对点全双工通话。并将系统应用在用于空中交通管制（ATC）的机场塔台模拟机中,逼真地模拟地面指挥员与空中飞行员的无线通讯,以及地面各指挥席间的相互通讯。在语音处理方面,系统采用G．729的音频压缩解码格式,解决了在实际应用中语音信号延迟、通讯声音质量低等问题。总结了此系统的性能与效率,以及为完善系统功能需要做的工作。     

Assessing problem solving in expert systems using human benchmarking

The human benchmarking approach attempts to assess problem solving in expert systems by measuring their performance against a range of human problem-solving performances. We established a correspondence between functions of the expert system GATES and human problem-solving skills required to perform a scheduling task. We then developed process and outcome measures and gave them to people of different assumed problem-solving ability. The problem-solving ability or “intelligence” of this expert system is extremely high in the narrow domain of scheduling planes to airport gates as indicated by its superior performance compared to that of undergraduates, graduate students and expert human schedulers (i.e. air traffic controllers). In general, the study supports the feasibility of using human benchmarking methodology to evaluate the problem-solving ability of a specific expert system.     

Objective Workload and Behavioural Response in Airport Radar Control Rooms

Previous research indicated that peak traffic and the duration of radio-communications were good predictors of behavioural response of air traffic controllers working in air route traffic control centres. In this study we investigated if these two measures of workload were generalisable to controllers (ATCs) working in radar facilities serving major airports. 3,110 observations were made on radar sectors at the 13 major radar control rooms in the U.S.A. A large number of air traffic variables and communication tasks were measured. Behavioural ratings were made by expert-observer ATC's. The results replicated previous findings that peak traffic and the duration of radio-communications functioned as behavioural stressors. Time monitoring and stand-by time also were found to predict behavioural responses. Careful consideration of these and other results led to the conclusion that peak traffic is the most generalisable environmental stressor for ATC's behaviour whereas the other workload measures are more correctly viewed as concomitants of the demand characteristics of ATC work.     

A socio-technical analysis of functional properties in a joint cognitive system: a case study in an aircraft cockpit

Abstract

In a socio-technical work domain, humans, device interfaces and artefacts all affect transformations of information flow. Such transformations, which may involve a change of auditory to visual information & vice versa or alter semantic approximations into spatial proximities from instruments readings, are generally not restricted to solely human cognition. This paper applies a joint cognitive system approach to explore a socio-technical system. A systems ergonomics perspective is achieved by applying a multi-layered division to transformations of information between, and within, human and technical agents. The approach uses the Functional Resonance Analysis Method (FRAM), but abandons the traditional boundary between medium and agent in favour of accepting aircraft systems and artefacts as agents, with their own functional properties and relationships. The joint cognitive system perspective in developing the FRAM model allows an understanding of the effects of task and information propagation, and eventual distributed criticalities, taking advantage of the functional properties of the system, as described in a case study related to the cockpit environment of a DC-9 aircraft.

Practitioner Summary: This research presents the application of one systemic method to understand work systems and performance variability in relation to the transformation of information within a flight deck for a specific phase of flight. By using a joint cognitive systems approach both retrospective and prospective investigation of cockpit challenges will be better understood.

Abbreviations: ATC: air traffic control; ATCO: air traffic controller; ATM: air traffic management; CSE: cognitive systems engineering; DSA: distributed situation awareness; FMS: flight management system; FMV: FRAM model visualize; FRAM: functional resonance analysis method; GF: generalised function; GW: gross weight; HFACS: human factors analysis and classification system; JCS: joint cognitive systems; PF: pilot flying; PNF: pilot not flying; SA: situation awareness; SME: subject matter expert; STAMP: systems theoretic accident model and processes; VBA: visual basic for applications; WAD: work-as-done; WAI: work-as-imagined; ZFW: zero fuel weight     

多重中断技术的软件模拟

多重中断技术在计算机中有着非常重要的地位.本文在软硬件逻辑功能等价性原理的思想指导下,介绍了如何运用软件开发环境模拟中断系统并用可视化界面展示之,实现多重中断工作过程.该中断系统的实现表明,在计算机上用软件模拟硬件,应用于实验、教学和进一步的研究中是具有可行性的.