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7 Victory and Defeat Conditions, Scoring and Feedback

7 Victory and Defeat Conditions, Scoring and Feedback

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SPRITE



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allows the user to play the role of the mayor and manage the island for a number

of years, with the mission of finding an appropriate balance between popularity, economy, attractivity, safety and ecology. SPRITE has a double pedagogical mission: informing the player about a major but often under-estimated risk

(coastal flood); and forcing him to reflect on policies for managing this risk. It

provides elected representatives with elements of reflection to design an efficient

and balanced management strategy, and allows residents to better understand

(and therefore accept) the policy carried out by their representatives.

The model is fully implemented in GAMA and the game is already playable.

The evaluation of engagement and learning is still preliminary but encouraging.

Short term future work will mainly be dedicated to this evaluation and subsequently improving the model, while longer term prospects include the refinement

of the mechanisms involved in the residents’ decision-making.

Acknowledgements. SPRITE was initially developed by a multidisciplinary

team at the CNRS MAPS 8 thematic school (https://maps.hypotheses.org/

evenements-maps-passes/maps-8) organised by the MAPS network dedicated to multiagent modelling applied to spatial phenomena. SPRITE then served as a basis for the

LittoSim project (directed by Nicolas B´ecu and Marion Amalric) funded by CNRS

D´efi Littoral call 2015, that developed a new, refined, and multiplayer model. Further

refinement of SPRITE (in particular with hydrological and political factors) is ongoing

in the MAGIL project (directed by Eric Barthelemy) funded by CNRS D´efi Littoral

call 2016.



References

1. Bersani, C., Coll.: Tempˆete Xynthia: retour d’exp´erience, ´evaluation et propositions

d’action. Technical report, Minist´ere ´ecologie, d´ev. durable et mer (2010)

2. Vinet, F., et al.: Le processus de production du risque “submersion marine” en

zone littorale: l’exemple des territoires Xynthia. NOROIS 222, 11–26 (2012)

3. Duvat-Magnan, V.: Les impacts de la tempˆete Xynthia sur les plages de l’ˆıle

d’ol´eron: les r´ealit´es du terrain. Institut du Littoral et de l’Environnement, Technical report (2010)

4. Le Cozannet, G., et al.: Evaluating uncertainties of future marine flooding occurrence as sea-level rises. Environ. Model. Softw. 73, 44–56 (2015)

5. Michael, D., Chen, S.: Serious Games: Games that Educate, Train, and Inform.

Thomson Course Technology, Boston (2006)

6. Sauve, L., Renaud, L., Gauvin, M.: Une analyse des ´ecrits sur les impacts du jeu

´

sur l’apprentissage. Revue des Sciences de l’Education

33(1), 89–107 (2007)

7. Crovato, S., Pinto, A., Giardullo, P., Mascarello, G., Neresini, F., Ravarotto, L.:

Food safety and young consumers: testing a serious game as a risk communication

tool. Food Control 62, 134–141 (2016)

8. Chadli, A.: Micro jeux et simulation multi-agents participative : apprentissage

des proc´edures de lutte contre les rongeurs arvicoles. Ph.D. thesis, Universit´e des

Sciences et de la Technologie d’Oran (2015)

9. Wouters, P., Spek, E., Oostendorp, H.: Current practices in serious game research:

a review from a learning outcomes perspective. In: Games-based learning advancements for multi-sensory human computer interfaces: techniques and effective practices, pp. 232–250. IGI Global (2009)



46



C. Adam et al.



10. Grignard, A., Taillandier, P., Gaudou, B., Vo, D.A., Huynh, N.Q., Drogoul, A.:

GAMA 1.6: advancing the art of complex agent-based modeling and simulation.

In: Boella, G., Elkind, E., Savarimuthu, B.T.R., Dignum, F., Purvis, M.K. (eds.)

PRIMA 2013. LNCS (LNAI), vol. 8291, pp. 117–131. Springer, Heidelberg (2013).

doi:10.1007/978-3-642-44927-7 9

11. Brandtzaeg, P.B., Folstad, A., Heim, J.: Enjoyment: lessons from karasek. In:

Blythe, M.A., Overbeeke, K., Monk, A.F., Wright, P.C. (eds.) Funology: From

Usability to Enjoyment. HCI, vol. 3, pp. 55–65. Springer, Rotterdam (2006)

12. Garris, R., Ahlers, R., Driskell, J.E.: Games, motivation, and learning: a research

and practice model. Simul. Gaming 33(4), 441–467 (2002)

13. Koster, R.: A Theory Of Fun For Game Design. Paraglyph Press, Scottsdale (2005)

14. van Ruijven, T.: Serious games as experiments for emergency management

research: a review. In: ISCRAM, May 2011



BDI Modelling and Simulation of Human

Behaviours in Bushfires

Carole Adam1(B) , Geoffrey Danet1 , John Thangarajah3 , and Julie Dugdale1,2

1



Grenoble Alpes University, LIG, 38000 Grenoble, France

{carole.adam,julie.dugdale}@imag.fr,

geoffrey.danet@gmail.com

2

University of Agder, Kristiansand, Norway

3

RMIT University, Melbourne, Australia

john.thangarajah@rmit.edu.au



Abstract. Each summer in Australia, bushfires burn many hectares of

forest, causing deaths, injuries, and destruction of property. Emergency

management strategies rely on expected citizens’ behaviour which differs

from reality. In order to raise their awareness about the real population

behaviour, we want to provide them with a realistic agent-based simulation. The philosophically-grounded BDI architecture provides a very

suitable approach but is little used due to the lack of adapted tools. This

paper uses this case study to illustrate two new tools to fill this gap: the

Tactics Development Framework (TDF) and GAMA BDI architecture.

Keywords: ABMS



1



· BDI architecture · Bushfires · Human behaviour



Introduction



Societies can manage crisis and emergency situations in several ways: adopt

urban and territory planning policies to reduce the risks (e.g. forbid construction

in exposed areas); raise awareness and prepare the population in advance; or

create efficient emergency management policies to deal with crisis when they

happen. Modelling and simulation offer tools to test the effects and complex

interactions of these different strategies without waiting for an actual crisis to

happen, without putting human lives at risk, with limited cost, and with a great

degree of control on all conditions and the possibility to reproduce exactly the

same situation as many times as needed.

When modelling human behaviour, mathematical, equation-based models are

too limited [1]; on the contrary, agent-based models offer many benefits [2].

They allow to capture emergent phenomena that characterise such complex systems; they provide an intuitive and realistic description of their behaviour; they

are flexible, offering different levels of abstraction by varying the complexity of

agents. However, the agents used are often too simplistic, reacting to environmental stimuli without any long-term reasoning. On the contrary, crisis situations

involve complex individual decision making, influenced by emotions (sometimes

causing irrational actions), and by the social context (effect of group, family).

c Springer International Publishing AG 2016

P. Diaz et al. (Eds.): ISCRAM-med 2016, LNBIP 265, pp. 47–61, 2016.

DOI: 10.1007/978-3-319-47093-1 5



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C. Adam et al.



The BDI (belief, desire, intention [3]) architecture is more sophisticated and

realistic. It describes agent behaviour in terms of mental attitudes, and has also

been used to formalise emotions [4]. BDI provides the perfect level of abstraction to describe human behaviour in terms of folk psychology, which is the preferred level of description for humans [5]. It therefore addresses the problem of

the scarcity of (quantitative) behaviour data by using qualitative data such as

witness statements or expert reports. Despite these advantages making it very

suitable for social simulation, BDI has had limited use in this field due to the

lack of adapted tools to harness its complexity [6]. We propose to fill this gap

by introducing to the emergency management community two new tools that

are still under development in the field of agent-based modelling and simulation

(ABMS): the TDF methodology that allows the designer to capture informal

descriptions of human behaviour into a conceptual agent-based model; and the

GAMA simulation platform that allows even non-computer scientists to implement a BDI model in an intuitive modelling language and conduct simulations.

We illustrate these tools on a particular case study: modelling the population

behaviour during the bushfires that burn every summer across many states in

Australia. Concretely, we focus on the so-called Black Saturday, 7th February

2009, when particularly strong bushfires killed 173 people and destroyed hectares

of bush and many properties in the state of Victoria. Reports [7] showed that

emergency management policies were designed based on an (ideal) expected

behaviour that differed from the residents’ actual behaviour on the day. It is

therefore important to provide deciders with a simulation to raise their awareness

about residents’ decision making, and let them try different strategies. For such

a simulation to lay valid results, it is important that the underlying human

behaviour model be as realistic as possible [8]. Currently, the available data

is mostly in the form of witness statements [9]. Given all of this, BDI based

agent-models are an ideal choice.

In previous work [10], we have shown how the TDF methodology could be

adapted to capture civilians’ behaviour in the fires. We used this methodology to

model the 6 archetypes of behaviours identified in the population [7] as 6 possible

roles for the agents of the system, each with their own goals and plans. However,

that report did not provide any statistics about the representation of the profiles

in the population, or their possible links with demographics attributes, so it

did not make it possible to initialise a representative simulation with the real

distribution of profiles. As a result, in the current paper we adopt a different

approach: we develop a single general behaviour for all of the civilians that

captures the different ways in which a civilian could behave in the case of a fire.

We then randomly initialise civilian agents with different beliefs that will guide

them along different paths of the possible behaviours at runtime. We observe and

log the behaviour of the agents, and use these logs to infer the different profiles

that emerge from them. The profiles are therefore not prescribed but observed.

Our hypothesis is that if our general behaviour model of the population is valid,

then we should observe the emergence of the same profiles of behaviour as the

ones identified from the population interviews after the Black Saturday bushfires.



BDI Modelling and Simulation of Human Behaviours in Bushfires



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BDI Modelling Methodology: TDF



In this case study, we aim to model the behaviour of the civilian population in the

Black Saturday bushfires, as gathered from witness statements from the affected

population following the bushfires [9]. When designing a conceptual model for

computational simulation, UML is the most widely used tool, mostly because

of its generality and ease of use, allowing one to describe entities in terms of

attributes and actions; but it is not well suited for modeling human behaviour

which is what is often required in disaster management and evacuation simulations such as our case study. On the other hand, as mentioned earlier, agentbased software development methodologies that develop systems using mental

attitudes of goals, events, plans, beliefs, capabilities etc. are well suited for these

systems. This is particularly relevant when transcribing behaviours described

by human witnesses as is the case here, since humans naturally tend to explain

their behaviour in terms of mental attitudes. For instance, take this extract: “I

looked out the window and saw some hazy smoke to the north-west. Gary said

that he thought it was just dust but we went outside and straight away we noticed

that we could smell smoke. It was about 12.45pm when we smelt the smoke and

as soon as that happened, Gary agreed to go and get the fire pump”. We can

make the mental attitudes involved more explicit: Gary (wrongly) believed for

a while that the smoke was just dust, but planned to get more information;

after going outside they perceived smoke and realised that it was coming from

a fire (belief update). As a result, he adopted the goal to get ready for the

fire, and started on their plan whose first action is to get the fire pump.

Whilst there are several agent-oriented software engineering methodologies

such as Prometheus, Tropos, O-MaSE, GAIA and others [11] here we introduce a more recent methodology purpose built for eliciting and encoding tactical/strategic behaviour in dynamic domains – TDF (Tactics Development

Framework) [12,13]. TDF is based on the Prometheus methodology [14], a

mature and popular agent-oriented software engineering methodology. A pilot

study has shown that TDF significantly improves comprehension of behavior

models, compared to UML [12]. Although TDF was initially designed to capture

and model military behaviour, we have shown in previous work [10] that this

framework can be adapted to model civilians’ descriptions of their behaviour in

crisis situations. The TDF methodology proceeds in following 3 phases as relevant to our case study: System specification: Identification of system-level artefacts, namely goals, scenarios, percepts, actions, data, actors and roles; Architectural design: Specification of the internals of the system, namely the agents that

play the different roles, the interactions between the agents (via protocols) if any,

and messages between agents; and Detailed design: Definition of the internals of

the agents, namely capabilities, plan diagrams and internal messages/sub-goals.

We now illustrate how we modelled our case study in TDF below.

2.1



System Specification: Analysis Overview



The purpose of this diagram is to identify the actors (entities external to the

system), the inputs (percepts) to and outputs (actions) from the system, and



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C. Adam et al.



identify scenarios (use-cases) that describe possible runs of the system. In our

case, the scenarios are examples of behaviours that we want to observe. A

given scenario will comprise a sequence of steps, where a step could include

goals, actions, percepts and sub-scenarios. Figure 1 illustrates part of the analysis overview diagram related to a scenario where the civilian defends his property

and Fig. 2 illustrates the detailed steps of the “Defend Property” scenario.

2.2



System Specification: Goal Overview



In the next step, we develop the goals for the agents (civilians) in the system.

The goal overview diagram illustrates how the high-level goals are decomposed

into more concrete goals. Figure 3 illustrate the goals that civilians adopted,

as extracted from the interviews. The different behaviours described in these

interviews result from two high-level goals: Defend Property (stay and defend

it), and Stay Alive (protect life of self and family). The relative priorities of

these goals depend on individual differences in various factors: awareness of

fire risk, fire training, physical condition, family situation (children to protect),

motivations to defend property (family house, livelihood), etc. These two highlevel goals are then decomposed as shown. The sub-goals of a goal can be either

OR, AND or CON decompositions. OR goals are a disjunction: a civilian can try to

stay alive by either taking cover at home, or by going to a shelter. AND goals are

a (possibly ordered) conjunction: to get to a shelter, one must first prepare their

house and themselves, then know a shelter location, then know a safe route to get

there, then finally follow that route. CON goals are concurrent goals where several

sub-goals must be pursued in parallel: to fight the fire, one must concurrently

monitor their health, the state of their house, and fight the fire (spraying water).



Fig. 1. Partial analysis overview diagram



Fig. 2. Example scenario: civilian defending property (detailed steps)



BDI Modelling and Simulation of Human Behaviours in Bushfires



51



Fig. 3. Goal overview for civilians: decomposition of 2 main high-level goals, “Stay

Alive” and “Defend Property”



2.3



System Specification: Role Overview



Having identified the goals, we next determine the roles to which these goals are

relevant: the 6 profiles of behaviour identified by [7] from the witness statements.

Usually, these roles will then be assigned to agents, however, in our case we only

model a single agent that can play any of these roles at run-time.

2.4



Architectural Design: System Overview



Figure 4 outlines the system overview, which shows the inputs and outputs to the

Civilian agent type. In general, when there are multiple agent types, this diagram

also captures the interactions between the agents via protocols. However, in our

case we have only one (type of) agent.

2.5



Detailed Design: Agent Overview



The next step consists in designing the agent overview for each agent type which

details the capabilities and plans of the agents used to achieve their goals. The

plans can be distributed in several capabilities, and each agent can be endowed

with one or more capabilities. Figure 5 shows the different capabilities that civilians are endowed with and the inputs and outputs relevant to each capability.



Fig. 4. System overview



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C. Adam et al.



Fig. 5. Agent overview, illustrating the capabilities of a Civilian agent



2.6



Detailed Design: Capability Overview



Figure 6 details the plans and sub-goals involved in the “defend property” capability. This diagram shows the flow of activities and also specifies the data elements required, for example the “FireData” that is read by the “DefendProperty” and written to by the “ContactFireStation” and “ObserveSurroundings”

plans. Note that this capability contains a sub-capability called “FightFire” that

handles the “fight fire” goal.



Fig. 6. Details of the “DefendProperty” capability



BDI Modelling and Simulation of Human Behaviours in Bushfires



2.7



53



Detailed Design: Plan Diagrams



Finally, each plan is detailed in a plan diagram, that is essentially a process

diagram, that can be directly translated into implementation code. A plan can

be triggered by external percepts or by internal goals, and is composed of several

(sequential or concurrent) steps. Steps can be atomic actions (external), activities

(internal processes, e.g. write data), or sub-goals. TDF allows to design one plan

diagram per plan; these diagrams are quite similar to UML activity diagrams.

Figure 7 shows the plan diagram for the “Defend Property” plan. It illustrates

that the plan is triggered by the “FireAlert” percept, and then concurrently

adopts goals to “PrepareProperty” and “Seek Fire Info”. Having adopted the

goals, it monitors the “FireData” information for when the fire is close enough

to adopt the goal to “Fight Fire”.

Figure 8 shows the plan diagram for the “ObserveSurroundings” plan. It illustrates a decision node where the agent considers if it safe outside before choosing

a mode of observation, followed by a merge node where the plan proceeds to the

next step, which is an activity that updates the agent’s fire data.



Fig. 7. DefendPropertyPlan



3

3.1



Fig. 8. ObserveSurroundingsPlan



Simulation Platform: GAMA

GIS and Agent-Based Modelling Architecture (GAMA)



GAMA [15,16] is an open source platform for agent-based modelling and simulation of complex spatialised systems. It provides built-in functions for using Geographical Information Systems (GIS) data, such as OpenStreetMap (OSM) for

fast and precise mapping of the environment. Simulations built with GAMA are

scalable, since the platform can deal with several thousands of agents, depending



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on the level of complexity of their architecture. Further, GAMA provides a very

simple and high level programming language called GAML, that allows even

non-programmers to simply build and maintain their own models. As a result,

it is widely used by designers from many different fields. Finally, it is supported

by an active development team that is progressively improving the software.

In particular, GAMA was recently extended with a BDI plugin [17,18] to

allow designers to easily create BDI agent models in the GAML language. They

can specify logical predicates, initialise their agents with beliefs and desires,

describe the effect of new percepts on the agent beliefs, and provide them with

a plan library. The BDI engine then lets the agents perceive their environment,

update their beliefs and desires, select an intention based on relative priorities

of their goals, and choose and execute an adapted plan to reach that goal.

3.2



Implementation of the Model



Environment. The BDI implementation for this particular case study is based

on our previous simulation [19] which used a finite-state machine (FSM) for

the agent architecture. Only the environment is the same: a square grid of 50

by 50 cells with two safe shelters and a number of houses each inhabited by

one resident, where a fire starts in a few initial cells and then propagates to

neighbouring cells at a speed that can be set as a parameter. The focus of this

paper is not on the realism of the environment or the fire behaviour, but on

illustrating the use of the GAMA BDI plugin to simply design complex human

behaviour models such as that developed using the TDF methodology.

Population. Residents are represented by a GAMA species Civilian. Their

attributes include: a health value which decreases due to injuries caused by the

fire or its radiant heat; a velocity when moving; a random awareness of risks

(perception radius); a random ability to fight fires (defense radius); a level of

determination to protect their property; a random risk aversion; and a reference

to its property. Civilians also maintain their own list of known fires and known

shelters. At the start of the simulation, all agents are unaware of any fires (since

there is none yet) and are waiting at home until they perceive one.

The next paragraphs illustrate how the model designed with TDF precisely

map with concepts provided by the BDI agent architecture of GAMA.

3.3



Mapping TDF Design with GAML Code



Predicates. In GAML, the designer first needs to describe the different logical

predicates that will be manipulated by the agent. This is basically the ontology

of the domain. The code snippet in Fig. 9 illustrates some predicates for our

bushfire domain. Predicates can be associated with a priority: here staying alive

has a priority based on the agent’s danger aversion, while protecting the property

has a priority based on the agent’s determination.



BDI Modelling and Simulation of Human Behaviours in Bushfires



55



predicate fire position ← new predicate(’’Know the fire

position’’);

...

predicate stay alive ← new predicate(’’Stay alive’’)

with priority rnd(danger aversion);

predicate protect property ← new predicate(’’Protect property’’)

with priority rnd(determination);



Fig. 9. Code snippet: predicates for domain ontology



Percepts. Agents can then be given perceptions, that explain how they interpret

stimuli coming in. These perceptions can add new beliefs or goals. They match

the percepts in TDF that represent the stimuli coming in from the environment

and triggering the agent’s plans. The code snippet in Fig. 10 shows how the

civilian agents perceive new fires (that are not yet in their list of known fires):

they add them to their list, and create a belief that there is a fire, and a desire

to get more information.



perceive target:(list(fire) - known fires) in: perception radius

{



}



add self to: myself.known fires;

ask myself

{

do add belief(fire position);

do add desire(get information);

}



Fig. 10. Code snippet: perception of an unknown fire



Actions. Agents are endowed with a number of actions, as specified in TDF.

There is no concept of capability to group actions together in GAML. The snippet in Fig. 11 illustrates 2 actions of civilians: prepare their building (the effect

value is computed based on some parameters not detailed here, and added to

their building resistance); and prepare themselves (similarly, a value is computed

and added to their total health, to simulate e.g. wearing protective clothes).

Plan Library. Similarly to TDF, actions are combined in plans. The agents are

endowed with a library of plans to achieve their goals. Each GAML plan is

defined with several features: the goal that it achieves (keyword intention); a

context condition (keyword when) that describes when this plan is applicable;

and a success condition (keyword finished when). The code snippet in Fig. 12



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