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A Common Work Space to Support the Air Traffic Control
Copyright @ IFAC Automated Systems Based on Human Skill, Aachen, Germany, 2000
A COMMON WORK SPACE TO SUPPORT THE AIR TRAFFIC CONTROL
M.P. Pacaux-Lemoine and S. Debernard
LAMIH, UMR CNRS 8530 Universite de Va/enciennes et du Hainaut-Cambresis Le Mont Houy, 59313 Valenciennes Cedex 9, France e-mail: marie-pierre.lemoine@univ-valenciennes.fr.serge.debernardriiJ.univ-valenciennes.fr
Abstract: This paper deals with the research of means to build a Human-Machine Cooperation in the Air Traffic Control. The experiment described aims at evaluating a principle of dynamic allocation of conflict resolution on a large scale simulator of air traffic control. Artificial and human agents have to cooperate to exchange information, to take decision and to command the air traffic. To analyse and define cooperation between agents, the know-how and the know-how-to-cooperate are defined. These concepts give a structure which allows to build a Common Work Space to support more efficiently the cooperation. Copyright @2000 IFAC Keywords: Air Traffic Control, Human-Machine Cooperation, Dynamic Allocation of Tasks, Common Work Space
1.
INTRODUCTION
A way to study cooperation between agents is to defme them with two concepts, the know-how and the know-how-to-cooperate. The first one deals with the individual model of an agent, from the information gathering to the action. The second one deals with the agent interaction with others agents. The know-howto-cooperate tries to integrate different forms, functions, means and controls to support cooperation between artificial agent (AA) and/or human agent (HA). After a description of these concepts, an example of human-machines cooperation (HMC) is presented: the Dynamic Allocation of Tasks (DAOT). This sort of HMC has been implemented in the Air Traffic Control (ATC) field for helping air controllers facing increase. This paper presents the assistance tools and the platform they are integrated on, and the experiments achieved with experienced controllers. The experiments underline the interest to define to a Common Work Space (CWS) where each agent is able to take into account the activity of the other agent so as to manage his/her/its own activity.
2.
COOPERATION
2.1. Dynamic Allocation a/Tasks
Dynamic allocation of tasks is a sort HMC which consists in sharing dynamically all the tasks to be performed between a human agent and an automated system. The main advantage expected is the regulation of the human workload (Millot, 1988). So, the automated system must be able to take care of some tasks, and provides a decision aid but also an action aid to the AA. The integration of this cooperation in a human-machine system requires to answer to different questions. The main questions are: Which interactions between the HA and the AA must be setting up to obtain an efficient cooperation? How assess this efficiency ? Which minimal interactions must be setting up between the two decision makers for building a CWS for avoiding interference on their current representation situation or diagnosis ? How display this CWS on a humanmachine interface and how update it in an optimal way for the HA (human model, automatic recognition of human intentions, etc.) ? An another question is: How allocate the shareable tasks between the decision-makers ? This allocation
can be managed by the HA himself/herself or by an AA (Rieger and Greenstein, 1982): - The former is called explicit allocation and the HA allocates the shareable tasks with a specific humanmachine interface. So the HA uses its own criteria for allocating shareable tasks to the support system. - The latter is called implicit allocation. An AA performs the allocations from an algorithm and criteria defmed by the designer (human workload, global performance, etc). The implicit allocation presents the ergonomic advantage to decrease the human workload but the AA can not modify the allocations. However, it is possible to adopt an intermediate type of task allocation - the explicit assisted allocation - which consists in an automatic allocation by the AA, but the HA can modify the allocations if it is necessary.
2.3. The know-how-to-cooperate A lot of definitions of the cooperation exist, but two definitions have caught our attention. From the sociology point of view, three cooperative forms are distinguished: the augmentative, debative and integrative cooperation (Schmidt, 1994). Differences between these forms come from the inability and/or the incapacity of an agent to perform alone a task. The augmentative form: this form appears when the capacity of an alone agent is not sufficient to realise a task (for example in the case of an overload). The know-how of each agent are similar and the task is decomposed into similar sub-tasks allocated to each agent. The integrative form : this know-how of an alone agent is not sufficient to realised a task. Others agents with different know-how have to participate to the task realisation. The task is decomposed into different sub-tasks and allocated to each agent according their/its know-how. The debativeform : the know-how of each agent is the same, the task is not decomposed into sub-tasks but realised by each agent in parallel to underline the differences and to choose the better result.
2.2. The know-how The know-how is the cleverness to solve problem. A human or artificial agent has the abilities, the experiences to build a know-how. It is composed of four main activities (Hoc and Lemoine, 98), the information elaboration, the diagnosis, the intervention decision, and the action. These classes of activity will be decomposed into sub-classes describing the evolution of the state of an information. Information Elaboration: It is the reading of the information provided by captors on the process. It is an information gathering goal if the information research doesn't succeed. An other state of the information is the information recovery if it is recorded in memory. Diagnosis: It is an identification or an inference or a testing. The identification is the interpretation of an information into a categorised one. Inference is also an interpretation, but it is uncertain. Testing is the test of an inference with new information. Decision Making: A decision is schematic or precise and will be evaluated. A Schematic Decision specifies a goal to be reached. It reflects the schematic feature of intervention decision planning. A Precise Decision is used when the decision is fully specified. A Decision Evaluation corresponds to the control or evaluation of one's own action or another agent's action.
From the psychology point of view, Hoc (Hoc, 1996) gives a definition of the cooperation according to two ideas, the interference management when two agents have to discuss a difference in their/its understanding of the process evolution, and the facilitation, action to make easier the activity of the other agent. These two points defme the functions of the cooperation. The interference management includes the detection and the management of an interference which appears between the activities of each agent. It would be necessary to build of a common frame of reference, a representation of a larger context to share to make easier the interference management and the mutual control between agents. The facilitation is composed of two main activities: the identification of the other agent's activity, the facilitation by helping the other agent, which will be realised by a task sharing. In addition to these functions of the cooperation, the control and the means of the cooperation are defined (Lemoine, 98). The control of the cooperation is decided according to the cooperation form, i.e. how an agent can interact with the other. The means of the cooperation are the means of communication between agents. It would be a display, verbalisations for the human agents, and computer structures for the artificial agents.
This list of sub-classes is certainly not exhaustive and the number of states of activity is dependent on the type of process and the control the agent is able to do. The know-how gives a model of the individual activity of an agent. But he/she/it has to supervise and control the process according to the activity of the others agents interacting with the same process. it is the reason why it is necessary to analyse the interaction between all the agents included in the process control and supervision by analysing the cooperation between them/its. A mean is to consider that the cooperation activity is a second type of activity, complementary to the first one, which allows to take into account the activity of the others agents.
2.4. Consequences for Dynamic Allocation of Tasks The DAOT can be defined with both concepts. A task is allocated to an agent according to his/her/its knowhow, but the rules of allocation are built according to the know-how-to-cooperate. A task is a part or all of the know-how. If the DAOT deals with a task sharing between a human and an artificial agent, the artificial 76
is defmed to refer to a conflict solvable by the human operator as well as SAINTEX. The latter - PLAF (French acronym for Planning of Allocation) (Crevits, 1993) - is dedicated to PCs and helps them to anticipate the influence on the existing traffic of entering aircraft, to measure the influence of the implementation of solutions from SAINTEX on the RC's conflict resolution. Three experimental conditions have been implemented to allow the evaluation of the assistance tools (Figure 2).
one can be dedicated to ensure the diagnostic tasks, or to apply a command specified by the human agent for example. The know-how-to-cooperate defines the task is better to allocate to an agent then an other according to rules (workload, efficiency, safety among others). It defmes the way to present the information about the allocation (how, when and what).
3.
APPLICATION TO AIR TRAFFIC CONTROL PLAF
Air Traffic Control is really a good experimental domain to apply and evaluate the cooperation and especially a Shared Work Space. Many ATC studies seem to underline the interest of a work space shared between many air traffic controllers and pilots (Boudes, 1996). So, in this paper, an experiment of DAT is described, two HA (a radar and a planning controller), and two AA (one artificial agent for each controller), have to ensure the security and the free flow of the air traffic. Figure 2 : Dynamic Allocation of Tasks
3. J. The experiment
The No Aid condition (NA) . The NA condition is used as a control condition and is similar to a real situation. The Explicit condition (EX) : In the explicit condition, allocation can be controlled either by PC or RC. Shareable conflicts are allocated, by default, to RC. They can be allocated to SAINTEX before a deadline defined by temporal constraints. In addition to SAINTEX, traffic and conflict prediction is performed by PLAF. The Assisted Explicit condition (AE) : In the assisted explicit condition, PLAF automatically proposes conflict allocations, on the basis of workload prediction. When it allocates a conflict, PC can change the allocation, but RC cannot directly control the allocation, apart from a request to
For this research an experimental platform SPECTRA V2 - was built to simulate a real control (Lemoine, et af., 1996). It integrates two control suites, the first for the radar controller (RC), and the second for the planning controller (PC). Each controller works with a radar and an electronic strip screen. A strip describes the flight plan of each aircraft entering the controlled sector. The tasks of each controller are different and complementary. PCs have a strategic role because they ensure the aircraft's entering and exiting while regulating RC's workload. RCs fill a tactical role because they have to fulfil aircraft's flight plans and provide traffic safety by conflict resolution (Figure I).
r
Pc.
The experiment took place during three weeks in the Eastern En-Route Control Centre of France, with three pairs (teams) of experienced controllers. Three similar scenarios were constructed with samples of real traffic of the Eastern sector of France airspace.
Entering traffic filtering
Strategical level Coordination between sectors Planning controller { Exiting traffic preparation
AIR-TRAFFIC CONTROL
From the methodology point of view, the know-how model and how-how-to-cooperate model are used to code the individual and cooperative activities of each AA and HA. The coding is based on the simultaneous and self-confrontation verbalisations of the air traffic controllers, and on the effective activity of all the agents.
L
. I Ieve I iTraffiC supervision T actlca Radar controller Aircraft guidance Data integration
Figure 1: Controllers' functions There are two types of assistance tools. The first SAINTEX (Angerand and Le Jeannic, 1992)assists aircraft guidance by conflict detection and resolution. It can detect all conflicts, and solve those between two level flights (aircraft with no change of flight level) by deflecting one of them, and those between a level flight and aircraft climbing or descending. Later, the notion of "shareable" conflict
3.2. Results The results of the activity analysis are in favour of the assisted explicit condition (Hoc and Lemoine, 1998). The performance is better, and the cooperation between the agents seems to be more operational. It would be the effect of the allocation mode which
77
prescribes a precise tasks allocation, and the involvement of an agent to facilitate the cooperation between one AA and one HA. An other main point of these results is the infonnation carrying by graphical displays, which constitute a reduced CWS, where SAfNTEX and PLAF give its results about the traffic analysis, and where RC and PC could display symbols to mark important infonnation, especially their conflicts detection and solving.
4.
more cooperative system than SAfNTEX and PLAF, more cooperative because the AA is able: - to take into account some schematic decision (directive) from the HA to implement it, - to communicate by the mean of a CWS, the understanding of the situation by the AA to the HA, - to detect the interference between the agents. The challenge of this research is to minimise for the HA, the cost to update the CWS, by identifying the controllers' intention from the traffic state and the directives given to AMANDA.
THE COMMON WORK SPACE
Each HA, for managing situations, builds himself7herself a frame of reference (FR). This FR is looked upon as a state of the situation and is made up of some different attributes: infonnation (stemming from activities of infonnation elaboration); problems (stemming from activities of diagnosis); strategies (stemming from activities of schematic decision making); solutions (stemming from activities of precise decision making); implementation of solutions.
REFERENCES Angerand L. and H. Le Jeannic, (1992) Bilan du projet SAINTEX, Note R92009, Centre d'Etudes de la Navigation Aerienne. Boudes N. and J.M. Cellier (1996) Functional biases in anticipation : the case of air traffic control. In: First International Conference on Applied Ergonomics, ICAE'96, Istanbul, Turkey, May 21-24, pp.882-885 Crevits, I. , S. Debernard, F. Vanderhaegen, P. Millot (1993). Multi-level cooperation in air traffic control. In: Fourth International Conference on Human-Machine Interaction and Artificial Intelligence in AeroSpace, Toulouse, France, September 28-30. Hoc J.M. (1996) Supervision et controle de processus: la cognition en situation dynamique. P.U.G, Grenoble, Collection Sciences & Technologie de la connaissance. Hoc J.-M. and M.P. Lemoine (1998) Cognitive evaluation of human-human and human-machine cooperation modes in Air Traffic Control. The International Journal of Aviation Psychology, Vo!. 8, N°t, pl-32. Lemoine M.-P, S. Debernard, I. Crevits, P. Millot (1996) Cooperation between humans and machines: first results of an experimentation of a multi-level cooperative organisation in air traffic control. Cooperative Supported Cooperative Work: ThejournalofCollaborative Computing, Vo!. 5, N°2-3, p299-321. Lemoine M.P. (1998) Cooperation HommesMachines dans les procedes complexes : modeles techniques et cognitift pour le Controle de Trafic Aerien. Memoire de Doctorat Specialite Automatique des Systemes Industriels et Humains. MilIot P. (1987). Supervision des procMes automatises, Edition Hennes, Paris. Schrnidt K. (1994) Cooperative work and its articulation : requirements for computer support. Le travail humain, tome 57, 0°4, pp.345-366. Rieger C.A. and Greenstein J.S. (1982). The allocation of tasks between human and computer in automated systems. In: IEEE International Conference on Cybertenics and Society, pp. 204-208, New York.
When two HA cooperate (this is the case in ATC), they build a virtual common frame of reference (CFR). For implementing a CFR on a machine (called CWS), it is necessary to understand how the HA builds a CFR. This construction requires some different human activities: - to update the CFR: correspond to the human activities for updating each CFR's attributes from their FR. - to control the CFR: the human activities aim to compare the CFR and their FR. These activities correspond to the mutual control and allow the interference detection on one or more attributes. - To manage the interference: firstly, the human activities correspond to a diagnosis on the differences between the CFR and the FR of an HA. Secondly, it is necessary to solve the interference. Three fonns of solving may be used by the HA: negotiation, acceptance, imposition. These fonns imply for HA cognitive and communication costs which are different. The negotiation aims at reducing the differences between the CFR and the FR by modifying one of them, on the basis of explanations between the agents. The acceptance is the update of the FR from the CFR. This acceptance is chosen when the cost of a negotiation is too important or when an agent wants to facilitate the activities of the other. The imposition corresponds to the opposite of the acceptance.
5.
CONCLUSION
The experiments SPECTRA V2 underlined the interest of one CWS. The concepts presented in this paper are at the moment implemented in AMANDA project. This project is realised in collaboration with the CENA (French acronym for Center of Study of Aerial Navigation). This project consists in building a
78
A COMMON WORK SPACE TO SUPPORT THE AIR TRAFFIC CONTROL
M.P. Pacaux-Lemoine and S. Debernard
LAMIH, UMR CNRS 8530 Universite de Va/enciennes et du Hainaut-Cambresis Le Mont Houy, 59313 Valenciennes Cedex 9, France e-mail: marie-pierre.lemoine@univ-valenciennes.fr.serge.debernardriiJ.univ-valenciennes.fr
Abstract: This paper deals with the research of means to build a Human-Machine Cooperation in the Air Traffic Control. The experiment described aims at evaluating a principle of dynamic allocation of conflict resolution on a large scale simulator of air traffic control. Artificial and human agents have to cooperate to exchange information, to take decision and to command the air traffic. To analyse and define cooperation between agents, the know-how and the know-how-to-cooperate are defined. These concepts give a structure which allows to build a Common Work Space to support more efficiently the cooperation. Copyright @2000 IFAC Keywords: Air Traffic Control, Human-Machine Cooperation, Dynamic Allocation of Tasks, Common Work Space
1.
INTRODUCTION
A way to study cooperation between agents is to defme them with two concepts, the know-how and the know-how-to-cooperate. The first one deals with the individual model of an agent, from the information gathering to the action. The second one deals with the agent interaction with others agents. The know-howto-cooperate tries to integrate different forms, functions, means and controls to support cooperation between artificial agent (AA) and/or human agent (HA). After a description of these concepts, an example of human-machines cooperation (HMC) is presented: the Dynamic Allocation of Tasks (DAOT). This sort of HMC has been implemented in the Air Traffic Control (ATC) field for helping air controllers facing increase. This paper presents the assistance tools and the platform they are integrated on, and the experiments achieved with experienced controllers. The experiments underline the interest to define to a Common Work Space (CWS) where each agent is able to take into account the activity of the other agent so as to manage his/her/its own activity.
2.
COOPERATION
2.1. Dynamic Allocation a/Tasks
Dynamic allocation of tasks is a sort HMC which consists in sharing dynamically all the tasks to be performed between a human agent and an automated system. The main advantage expected is the regulation of the human workload (Millot, 1988). So, the automated system must be able to take care of some tasks, and provides a decision aid but also an action aid to the AA. The integration of this cooperation in a human-machine system requires to answer to different questions. The main questions are: Which interactions between the HA and the AA must be setting up to obtain an efficient cooperation? How assess this efficiency ? Which minimal interactions must be setting up between the two decision makers for building a CWS for avoiding interference on their current representation situation or diagnosis ? How display this CWS on a humanmachine interface and how update it in an optimal way for the HA (human model, automatic recognition of human intentions, etc.) ? An another question is: How allocate the shareable tasks between the decision-makers ? This allocation
can be managed by the HA himself/herself or by an AA (Rieger and Greenstein, 1982): - The former is called explicit allocation and the HA allocates the shareable tasks with a specific humanmachine interface. So the HA uses its own criteria for allocating shareable tasks to the support system. - The latter is called implicit allocation. An AA performs the allocations from an algorithm and criteria defmed by the designer (human workload, global performance, etc). The implicit allocation presents the ergonomic advantage to decrease the human workload but the AA can not modify the allocations. However, it is possible to adopt an intermediate type of task allocation - the explicit assisted allocation - which consists in an automatic allocation by the AA, but the HA can modify the allocations if it is necessary.
2.3. The know-how-to-cooperate A lot of definitions of the cooperation exist, but two definitions have caught our attention. From the sociology point of view, three cooperative forms are distinguished: the augmentative, debative and integrative cooperation (Schmidt, 1994). Differences between these forms come from the inability and/or the incapacity of an agent to perform alone a task. The augmentative form: this form appears when the capacity of an alone agent is not sufficient to realise a task (for example in the case of an overload). The know-how of each agent are similar and the task is decomposed into similar sub-tasks allocated to each agent. The integrative form : this know-how of an alone agent is not sufficient to realised a task. Others agents with different know-how have to participate to the task realisation. The task is decomposed into different sub-tasks and allocated to each agent according their/its know-how. The debativeform : the know-how of each agent is the same, the task is not decomposed into sub-tasks but realised by each agent in parallel to underline the differences and to choose the better result.
2.2. The know-how The know-how is the cleverness to solve problem. A human or artificial agent has the abilities, the experiences to build a know-how. It is composed of four main activities (Hoc and Lemoine, 98), the information elaboration, the diagnosis, the intervention decision, and the action. These classes of activity will be decomposed into sub-classes describing the evolution of the state of an information. Information Elaboration: It is the reading of the information provided by captors on the process. It is an information gathering goal if the information research doesn't succeed. An other state of the information is the information recovery if it is recorded in memory. Diagnosis: It is an identification or an inference or a testing. The identification is the interpretation of an information into a categorised one. Inference is also an interpretation, but it is uncertain. Testing is the test of an inference with new information. Decision Making: A decision is schematic or precise and will be evaluated. A Schematic Decision specifies a goal to be reached. It reflects the schematic feature of intervention decision planning. A Precise Decision is used when the decision is fully specified. A Decision Evaluation corresponds to the control or evaluation of one's own action or another agent's action.
From the psychology point of view, Hoc (Hoc, 1996) gives a definition of the cooperation according to two ideas, the interference management when two agents have to discuss a difference in their/its understanding of the process evolution, and the facilitation, action to make easier the activity of the other agent. These two points defme the functions of the cooperation. The interference management includes the detection and the management of an interference which appears between the activities of each agent. It would be necessary to build of a common frame of reference, a representation of a larger context to share to make easier the interference management and the mutual control between agents. The facilitation is composed of two main activities: the identification of the other agent's activity, the facilitation by helping the other agent, which will be realised by a task sharing. In addition to these functions of the cooperation, the control and the means of the cooperation are defined (Lemoine, 98). The control of the cooperation is decided according to the cooperation form, i.e. how an agent can interact with the other. The means of the cooperation are the means of communication between agents. It would be a display, verbalisations for the human agents, and computer structures for the artificial agents.
This list of sub-classes is certainly not exhaustive and the number of states of activity is dependent on the type of process and the control the agent is able to do. The know-how gives a model of the individual activity of an agent. But he/she/it has to supervise and control the process according to the activity of the others agents interacting with the same process. it is the reason why it is necessary to analyse the interaction between all the agents included in the process control and supervision by analysing the cooperation between them/its. A mean is to consider that the cooperation activity is a second type of activity, complementary to the first one, which allows to take into account the activity of the others agents.
2.4. Consequences for Dynamic Allocation of Tasks The DAOT can be defined with both concepts. A task is allocated to an agent according to his/her/its knowhow, but the rules of allocation are built according to the know-how-to-cooperate. A task is a part or all of the know-how. If the DAOT deals with a task sharing between a human and an artificial agent, the artificial 76
is defmed to refer to a conflict solvable by the human operator as well as SAINTEX. The latter - PLAF (French acronym for Planning of Allocation) (Crevits, 1993) - is dedicated to PCs and helps them to anticipate the influence on the existing traffic of entering aircraft, to measure the influence of the implementation of solutions from SAINTEX on the RC's conflict resolution. Three experimental conditions have been implemented to allow the evaluation of the assistance tools (Figure 2).
one can be dedicated to ensure the diagnostic tasks, or to apply a command specified by the human agent for example. The know-how-to-cooperate defines the task is better to allocate to an agent then an other according to rules (workload, efficiency, safety among others). It defmes the way to present the information about the allocation (how, when and what).
3.
APPLICATION TO AIR TRAFFIC CONTROL PLAF
Air Traffic Control is really a good experimental domain to apply and evaluate the cooperation and especially a Shared Work Space. Many ATC studies seem to underline the interest of a work space shared between many air traffic controllers and pilots (Boudes, 1996). So, in this paper, an experiment of DAT is described, two HA (a radar and a planning controller), and two AA (one artificial agent for each controller), have to ensure the security and the free flow of the air traffic. Figure 2 : Dynamic Allocation of Tasks
3. J. The experiment
The No Aid condition (NA) . The NA condition is used as a control condition and is similar to a real situation. The Explicit condition (EX) : In the explicit condition, allocation can be controlled either by PC or RC. Shareable conflicts are allocated, by default, to RC. They can be allocated to SAINTEX before a deadline defined by temporal constraints. In addition to SAINTEX, traffic and conflict prediction is performed by PLAF. The Assisted Explicit condition (AE) : In the assisted explicit condition, PLAF automatically proposes conflict allocations, on the basis of workload prediction. When it allocates a conflict, PC can change the allocation, but RC cannot directly control the allocation, apart from a request to
For this research an experimental platform SPECTRA V2 - was built to simulate a real control (Lemoine, et af., 1996). It integrates two control suites, the first for the radar controller (RC), and the second for the planning controller (PC). Each controller works with a radar and an electronic strip screen. A strip describes the flight plan of each aircraft entering the controlled sector. The tasks of each controller are different and complementary. PCs have a strategic role because they ensure the aircraft's entering and exiting while regulating RC's workload. RCs fill a tactical role because they have to fulfil aircraft's flight plans and provide traffic safety by conflict resolution (Figure I).
r
Pc.
The experiment took place during three weeks in the Eastern En-Route Control Centre of France, with three pairs (teams) of experienced controllers. Three similar scenarios were constructed with samples of real traffic of the Eastern sector of France airspace.
Entering traffic filtering
Strategical level Coordination between sectors Planning controller { Exiting traffic preparation
AIR-TRAFFIC CONTROL
From the methodology point of view, the know-how model and how-how-to-cooperate model are used to code the individual and cooperative activities of each AA and HA. The coding is based on the simultaneous and self-confrontation verbalisations of the air traffic controllers, and on the effective activity of all the agents.
L
. I Ieve I iTraffiC supervision T actlca Radar controller Aircraft guidance Data integration
Figure 1: Controllers' functions There are two types of assistance tools. The first SAINTEX (Angerand and Le Jeannic, 1992)assists aircraft guidance by conflict detection and resolution. It can detect all conflicts, and solve those between two level flights (aircraft with no change of flight level) by deflecting one of them, and those between a level flight and aircraft climbing or descending. Later, the notion of "shareable" conflict
3.2. Results The results of the activity analysis are in favour of the assisted explicit condition (Hoc and Lemoine, 1998). The performance is better, and the cooperation between the agents seems to be more operational. It would be the effect of the allocation mode which
77
prescribes a precise tasks allocation, and the involvement of an agent to facilitate the cooperation between one AA and one HA. An other main point of these results is the infonnation carrying by graphical displays, which constitute a reduced CWS, where SAfNTEX and PLAF give its results about the traffic analysis, and where RC and PC could display symbols to mark important infonnation, especially their conflicts detection and solving.
4.
more cooperative system than SAfNTEX and PLAF, more cooperative because the AA is able: - to take into account some schematic decision (directive) from the HA to implement it, - to communicate by the mean of a CWS, the understanding of the situation by the AA to the HA, - to detect the interference between the agents. The challenge of this research is to minimise for the HA, the cost to update the CWS, by identifying the controllers' intention from the traffic state and the directives given to AMANDA.
THE COMMON WORK SPACE
Each HA, for managing situations, builds himself7herself a frame of reference (FR). This FR is looked upon as a state of the situation and is made up of some different attributes: infonnation (stemming from activities of infonnation elaboration); problems (stemming from activities of diagnosis); strategies (stemming from activities of schematic decision making); solutions (stemming from activities of precise decision making); implementation of solutions.
REFERENCES Angerand L. and H. Le Jeannic, (1992) Bilan du projet SAINTEX, Note R92009, Centre d'Etudes de la Navigation Aerienne. Boudes N. and J.M. Cellier (1996) Functional biases in anticipation : the case of air traffic control. In: First International Conference on Applied Ergonomics, ICAE'96, Istanbul, Turkey, May 21-24, pp.882-885 Crevits, I. , S. Debernard, F. Vanderhaegen, P. Millot (1993). Multi-level cooperation in air traffic control. In: Fourth International Conference on Human-Machine Interaction and Artificial Intelligence in AeroSpace, Toulouse, France, September 28-30. Hoc J.M. (1996) Supervision et controle de processus: la cognition en situation dynamique. P.U.G, Grenoble, Collection Sciences & Technologie de la connaissance. Hoc J.-M. and M.P. Lemoine (1998) Cognitive evaluation of human-human and human-machine cooperation modes in Air Traffic Control. The International Journal of Aviation Psychology, Vo!. 8, N°t, pl-32. Lemoine M.-P, S. Debernard, I. Crevits, P. Millot (1996) Cooperation between humans and machines: first results of an experimentation of a multi-level cooperative organisation in air traffic control. Cooperative Supported Cooperative Work: ThejournalofCollaborative Computing, Vo!. 5, N°2-3, p299-321. Lemoine M.P. (1998) Cooperation HommesMachines dans les procedes complexes : modeles techniques et cognitift pour le Controle de Trafic Aerien. Memoire de Doctorat Specialite Automatique des Systemes Industriels et Humains. MilIot P. (1987). Supervision des procMes automatises, Edition Hennes, Paris. Schrnidt K. (1994) Cooperative work and its articulation : requirements for computer support. Le travail humain, tome 57, 0°4, pp.345-366. Rieger C.A. and Greenstein J.S. (1982). The allocation of tasks between human and computer in automated systems. In: IEEE International Conference on Cybertenics and Society, pp. 204-208, New York.
When two HA cooperate (this is the case in ATC), they build a virtual common frame of reference (CFR). For implementing a CFR on a machine (called CWS), it is necessary to understand how the HA builds a CFR. This construction requires some different human activities: - to update the CFR: correspond to the human activities for updating each CFR's attributes from their FR. - to control the CFR: the human activities aim to compare the CFR and their FR. These activities correspond to the mutual control and allow the interference detection on one or more attributes. - To manage the interference: firstly, the human activities correspond to a diagnosis on the differences between the CFR and the FR of an HA. Secondly, it is necessary to solve the interference. Three fonns of solving may be used by the HA: negotiation, acceptance, imposition. These fonns imply for HA cognitive and communication costs which are different. The negotiation aims at reducing the differences between the CFR and the FR by modifying one of them, on the basis of explanations between the agents. The acceptance is the update of the FR from the CFR. This acceptance is chosen when the cost of a negotiation is too important or when an agent wants to facilitate the activities of the other. The imposition corresponds to the opposite of the acceptance.
5.
CONCLUSION
The experiments SPECTRA V2 underlined the interest of one CWS. The concepts presented in this paper are at the moment implemented in AMANDA project. This project is realised in collaboration with the CENA (French acronym for Center of Study of Aerial Navigation). This project consists in building a
78